Vincent A. Hackley National Institute of Standards and Technology
Anil K. Patri National Cancer Institute at Frederick
Judith Stein GE Global Research
Brij M. Moudgil University of Florida
FF1: Special Invited Session: The Regulatory and Standards for Nano Biotechnology: Institutional Perspectives and Panel Discussion
Tuesday PM, April 10, 2007
Room 2018 (Moscone West)
9:30 AM - *FF1.1
Health and Medicine in the National Nanotechnology Initiative.
Clayton Teague 1 Show Abstract
1 , National Nanotechnology Coordination Office, Arlington, Virginia, United States
9:45 AM - *FF1.2
Cancer Nanotechnology: An Opportunity for a New Class of Diagnostic and Therapeutic Solutions.
Piotr Grodzinski 1 Show Abstract
1 Office of the Director, National Cancer Institute, Bethesda, Maryland, United States
National Cancer Institute is engaged in efforts to harness the power of nanotechnology to radically change the way we diagnose, image, and treat cancer. Novel and multi-functional nanodevices will be capable of detecting cancer at its earliest stages, pinpointing its location within the body, delivering anticancer drugs specifically to malignant cells, and determining if these drugs are effective. Functionalized nanoparticles would deliver multiple therapeutic agents to tumor sites in order to simultaneously attack multiple points in the pathways involved in cancer. Such nano-therapeutics are expected to increase the efficacy of drugs while dramatically reducing potential side effects. In vivo biosensors would have the capability of detecting tumors and metastatic lesions that are far smaller than those detectable using current, conventional technologies. Furthermore, they will provide rapid information on whether a given therapy is working as expected.In order to further these research goals, NCI Alliance for Nanotechnology in Cancer has been formed in 2004. The Alliance is investing $144.3 million over the next 5 years to pursue applied nanotechnologies for cancer detection, therapy, and prevention with an aim to achieve clinical translational stage of these technologies towards culmination of the program. The Alliance funds Centers of Cancer Nanotechnology Excellence, the development of nanotechnology platforms, and internal Nanotechnology Characterization Laboratory.This presentation will describe the details behind the organization and science and technology of the Alliance.
10:00 AM - *FF1.3
A NIST Perspective on Nanobiotechnology: Standards as an Enabler of Products.
Richard Kayser 1 Show Abstract
1 , NIST, Gaithersburg, Maryland, United States
The National Institute of Standards and Technology, NIST, has an extensive nanotechnology portfolio to serve the measurement needs of its customers during every stage of technological innovation. This presentation will introduce the nanometrology program at NIST, emphasizing its impacts, both current and potential, on the biotechnology area. NIST’s main areas of focus will be described, as well as the influences of the needs of the biotechnology arena on the continual shaping of this program. NIST nanobiotechnology programs relate to the entire technological innovation continuum, from materials discovery/R&D through the end-use (and disposal) of a product. During the materials discovery and applied R&D stages, NIST measurement science provides many of the tools necessary to enable the components that will one day be inserted into commercialized products. NIST resources, such as the Advanced Measurement Laboratory (AML), provide measurement tools needed to increase the nation’s capability to understand phenomena at the nanoscale and accelerate technological innovation. NIST perspectives on measurement needs and solutions in the earlier stages of technological innovation will be discussed in the context of the nanobiotechnology sector. As nanobiotechnology products move toward the marketplace, the need for standards becomes clear, not only for potential FDA regulatory policy, but also for interlaboratory comparisons, and to support the development of assay protocols and other products anticipated from such organizations as NCL and ASTM. NIST work in standards and standard reference materials / reference materials (SRM/RM) will be discussed in this light. NIST priorities at all stages are strongly influenced by an understanding of the needs of the sectors to which it provides services. In this light, partnerships are extremely important in optimizing the path to providing appropriate techniques for application in nanobiotechnology. The NIST role in a NIST-NCI-FDA partnership will be presented as an example.Finally, a NIST perspective on the future of measurement science and technology work for nanobiotechnology will be presented.
10:15 AM - *FF1.4
Characterization of Nanomaterials Intended for Medical Applications.
Scott McNeil 1 Show Abstract
1 Nanotechnology Characterization Laboratory, NCI-Frederick, Inc., Frederick, Maryland, United States
The Nanotechnology Characterization Laboratory (NCL) conducts preclinical efficacy and toxicity testing of nanoparticles intended for cancer therapeutics and diagnostics. The NCL is a collaborating partnership between NCI, the U.S. Food and Drug Administration and the National Institute of Standards and Technology. As part of its assay cascade, NCL characterizes nanoparticles' physical attributes, their in vitro biological properties, and their in vivo compatibility using animal models. The Laboratory facilitates the rapid transition of basic nanoscale particles and devices into clinical applications by providing the critical infrastructure and characterization services to nanomaterial providers. It is a national resource available to investigators from academia, industry and government. The presentation will provide an overview of the NCL; discuss parameters that are critical to biocompatibility, and present assays used for preclinical characterization of nanoparticles.
10:30 AM - *FF1.5
FDA Regulatory Considerations for Nanotechnology Drug Products.
Nakissa Sadrieh 1 , Subhas Malghan 2 Show Abstract
1 Office of Pharmaceutical Science/CDER, FDA, Silver Spring, Maryland, United States, 2 Office of Science Engineering Laboratories, CDRH/FDA, Rockville, Maryland, United States
Tuesday, April 10New Title and New Presenter*FF1.5 @ 9:30 amFDA Regulatory Considerations for Nanotechnology Devices.Subhas Malghan, Office of Science Engineering Laboratories, CDRH/DA, Silver Spring, Maryland.
10:45 AM - *FF1.6
National Toxicology Program Activities Evaluating the Safety of Materials Produced Through Nanotechnology.
Paul Howard 1 Show Abstract
1 Department of Health & Human Services, National Center for Toxicological Research - U. S. Food and Drug Administration, Jefferson, Arkansas, United States
The unique and diverse physico-chemical properties of nanoscale materials suggest that their toxicological properties may differ from materials of similar composition but larger size. Studies suggest that particle size, surface area and surface chemistry of engineered nanoscale materials can impact toxicity equally, if not more so, than chemical composition. The National Toxicology Program (NTP) (ntp.niehs.nih.gov) is a multi agency program headquartered at the NIEHS that coordinates toxicology research and testing programs within the federal government and conducts research to provide information about potentially toxic chemicals to health, regulatory, and research agencies, scientific and medical communities, and the public. The NTP is currently engaged in a research program that is evaluating the toxicological properties of current major nanoscale materials classes. These materials represent a cross-section of composition, size, surface coatings, and physico-chemical properties. The studies are designed to investigate fundamental questions concerning how nanoscale materials are absorbed and distributed in vivo and whether they can adversely impact biological systems. Some of these fundamental questions include: What are the appropriate methods for detection and quantification of nanoscale particles in tissues? How are nanoscale materials absorbed, distributed in the body and taken up by cells? Are there novel toxicological interactions? The NTP's nanotechnology safety initiative (http://ntp.niehs.nih.gov/go/nanotech) is focusing research with respect to specific types or groups of nanoscale materials: Non-medical, commercially relevant/available nanoscale materials to which humans are intentionally being exposed, e.g., cosmetics and sunscreens; Nanoscale materials representing specific classes (e.g., fullerenes and metal oxides) so that information can be extrapolated to other members of those classes; Subsets of nanomaterials to test specific hypotheses about a key physiochemical parameter (e.g., size, composition, shape, or surface chemistry) that might be related to biological activity. Ongoing research activities are addressing (1) the fate and distribution of nanoscale metal oxides and quantum dots in the body following their dermal application to rodents with attention given to the role of surface coating, size, polarity, vehicle, and skin condition on the ability of nanoscale TiO2 to penetrate the skin; (2) whether nanoscale TiO2 and ZnO applied dermally to mice in combination with UVA-containing light affects cell signaling, and (3) the potential for TiO2 applied dermally to haired and hairless mice in combination with UV-containing light to cause skin cancer.
11:15 AM - *FF1.7
ISO Standards and Initiatives in Nanoscale Measurement and the Health, Safety and Environmental Effects of Nanomaterials
Kevin Powers 1 Show Abstract
1 Particle Engineering Research Center, University of Florida, Gainesville, Florida, United States
This presentation reviews existing ISO standards relating to the measurement of nanoscale materials and current ISO initiatives concerning best practices for preserving the occupational health and safety of those involved in the manufacture and use of nanotechnologies. The advent of the nanotechnology revolution has raised serious concerns regarding potential health and safety hazards associated with the production and use of engineered nanomaterials. These issues have prompted widespread calls that regulatory agencies evaluate and take appropriate actions to protect human health and safety, preserve the environment and enable international commerce in nanotechnologies. Both national and international regulatory agencies and standards organizations such as EPA, NIOSH, ANSI, BSI, APPIE, DIN, EEC, ISO and others are collaborating to develop a unified approach to standardization. There are a variety of existing international standards that address the measurement of nanoscale materials and the quantification of exposure to some types of airborne nano or ultrafine materials. Relevant national and ISO documents are often difficult to find due to the large number of technical committees, often linked to specific industrial sectors. Recently, a new ISO committee TC229 entitled “Nanotechnologies” was established to address issues specifically associated with engineered nanomaterials. It is the purpose of this committee to assemble international experts to evaluate current standards, compile relevant materials and develop a strategy for developing international standards relating to nanotechnology. Initially, three working groups will develop international standards and best practices in the areas of terminology, metrology, and occupational health and safety.
11:30 AM - *FF1.8
Standards for Nanotechnology: Essential Tools for Effective Regulation and Risk Communication.
Kristen Kulinowski 1 Show Abstract
1 Department of Chemistry, Rice University, Houston, Texas, United States
The risks and benefits of nanotechnology are being considered carefully by stakeholders from all communities. As part of this discourse it is essential that all parties agree to a shared set of documents that describe the terms of nanotechnology, the methods of characterizing the materials, and where possible agree on the best practices for minimizing nanotechnology’s risks. Such documents are standards, and when drafted and reviewed by diverse stakeholders they are referred to as ‘consensus’ standards. ASTM launched committee E56 on nanotechnology several years ago to produce consensus standards across a wide range of issues in nanotechnology. Any person, from any country, is eligible to join E56 and participate in its largely electronic standards drafting and balloting process; its nearly three hundred plus members work in small teams on specific terminology, characterization, toxicology and risk management documents. This talk will describe the current status of ASTM standards and the role those standards will play in the developing area of nanotechnology policy.
11:45 AM - *FF1.9
The Global Health Program at the Bill & Melinda Gates Foundation.
Steve Buchsbaum 1 Show Abstract
1 , Bill & Melinda Gates Foundation, Seattle, Washington, United States
I will provide a brief overview of the Global Health activities at the Bill & Melinda Gates Foundation with a focus on the strategy and areas of investment in nanotechnologies that contribute to critical technologies for global health. I will focus on the investments made as part of the Grand Challenges in Global Health under the first three Grand Challenges with the goal of Improving Childhood Vaccines. I will describe the process we are currently developing to better establish technical goals and specifications to guide our investments in these areas.
12:00 PM - *FF1.10
CYT-6091 (Aurimune™): A Colloidal Gold-Based Tumor-Targeted Nanomedicine.
Lawrence Tamarkin 1 , Lonni Myer 1 , Ryan Haynes 1 , Guilio Paciotti 1 Show Abstract
1 , CytImmune, Rockville, Maryland, United States
Targeting potent anti-cancer therapeutics to solid tumors is best accomplished by first avoiding recognition and uptake by the immune system and second by limiting the biodistribution of the drug to the tumor. We have achieved these objectives by binding tumor necrosis factor alpha (TNF) to the surface of 30 nm pegylated colloidal gold particles. Pegylation of the gold nanoparticles is accomplished by binding thiolated polyethylene glycol in between the TNF molecules on the surface of the gold nanoparticles. This formulation is termed CYT-6091 (Aurimune). The liver or spleen (the RES) take-up little or no drug 6 hr after CYT-6091 is injected into mice, and TNF levels in the tumors increase over this time period (in contrast to decreasing levels of TNF seen in healthy tissues). Electron micrographs also show gold nanoparticles in the tumors, but few or no particles in healthy tissue. By getting more TNF to the tumors, CYT-6091 is both safer and more effective in causing tumor regression in mice. CYT-6091 has also been given to dogs with naturally occurring cancers. Most notably in both dogs with cancer and in healthy rabbits, CYT-6091 caused fever, but did not induce hypotension. Historically, hypotension has been the dose-limiting toxicity for TNF and the primary reason for its failure in human clinical trials. For human testing, the manufacturing of CYT-6091 was successfully scaled-up and produced under cGMP. CYT-6091 is currently being tested in end-stage disease cancer patients in an NCI sponsored Phase I clinical trial.
12:15 PM - *FF1.11
Development and Regulatory Considerations of a Dendrimer-Based Pharmaceutical for Prevention of HIV and Genital Herpes.
Jeremy Paull 1 , Lori Reyna 2 Show Abstract
1 Regulartory & Clinical Affairs, Starpharma Pty Ltd, Melbourne, Victoria, Australia, 2 , Dendritic Nanotechnologies, Inc., Mt. Pleasant, Michigan, United States
FF2: Nanoscale Drug Delivery Systems
Tuesday PM, April 10, 2007
Room 2018 (Moscone West)
2:30 PM - **FF2.1
Nanotechnology in Drug Delivery.
James Baker 1 , Paul Makidon 2 Show Abstract
1 , University of Michigan, Ann Arbor, Michigan, United States, 2 Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, Michigan, United States
3:00 PM - FF2.2
Tumor-Associated Carbohydrate Antigen-Coated Nanoparticles: Synthesis, in vitro and in vivo Characterization.
Joseph Barchi 4 , Kate Rittenhouse-Olson 1 , Jamie Heimburg 1 , Sergei Svarovsky 3 , Anil Patri 2 , Jiwen Zheng 2 , Andreas Sundgren 4 Show Abstract
4 Medicinal Chemistry, National Cancer Institute at Frederick, Frederick, Maryland, United States, 1 Department of Biotechnical and Clinical Laboratory Sciences, University of Buffalo, Buffalo, New York, United States, 3 Center for Glycosciences and Technology, The Biodesign Institute at Arizona State University, Tempe, Arizona, United States, 2 Nanotechnology Characterization Laboratory, National Cancer Institute at Frederick, SAIC-Frederick, Inc., Frederick, Maryland, United States
Cell surface carbohydrates play unique roles in a host of biologically relevant events such as cell differentiation, adhesion and development. They also mediate many undesired processes such as pathogenic infection and tumor metastasis. A common feature of all tumor cells is the altered expression and presentation of surface glycans that serve as “non-self” structures that can be recognized by the immune system. For many years, these tumor-associated carbohydrate antigens (TACA’s) have been employed in the development of tumor vaccines with varying degrees of success. In addition, these sugars may mediate tumor cell adhesion during the metastatic cascade. We have previously succeeded in preparing both gold nanoparticles and quantum dot nanocrystals that were coated with specific TACA’s. We have concentrated on the Thomsen Friedenreich (TF) antigen disaccharide (Galβ1-3GalNAcα-O-Ser/Thr) and have shown that gold particles coated with TF antigen can either promote or inhibit metastasis in vivo. Here we describe our progress toward the synthesis of a number of these multivalent nanoscaffolds and report on our characterization efforts and how the size and surface chemistry of the particles relates to their biological activities.
3:15 PM - FF2.3
A Simple Route To Gold Nanoshell and Liposome Mediated Therapeutics.
Brian Prevo 1 , Joseph Zasadzinski 1 Show Abstract
1 Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California, United States
This project addresses the need for simple, scalable paths to benign core shell particles for photothermal stimulation. Near infrared (NIR) is especially useful for in vivo applications as physiological media are relatively transparent to NIR light. Nanoscopic hollow shells of gold possess a strong NIR plasmon absorption, making them a potentially useful tool for plasmonic heating effects. Recent efforts in this field have demonstrated an array of different imaging and therapeutic applications taking advantage of this effect. Galvanic replacement chemistry offers a facile ‘one pot’ route to metal nanoshell synthesis, providing a distinct advantage over conventional layer by layer nanoshell fabrication techniques. Template metallic nanoparticles (e.g. silver) act as reductants, nucleating the desired metal nanoshell (e.g. gold) around them provided that the template has a lower standard reduction potential. The resulting aqueous core/metal shell particles can be tunably varied from ~ 20 - 100nm shells with varying thickness (depending on reagent ratios). The use of pulsed NIR laser irradiation for inducing plasmonic heating effects minimizes the temperature rise in the surrounding media due to the fast relaxation times (~ ps) of the metal particles. Gold nanoshell absorption characteristics change as a function of time and of laser energy. The kinetics of the laser attenuation by the particles correlates well with the corresponding UV/Vis/NIR spectroscopy, TEM, experimental calorimetry, and heat transfer calculations. While bulk temperatures do not rise appreciably, the energy release per pulse is sufficient to locally vaporize water molecules inducing a microscopic volume change which could serve as an optically activated pressure switch. We are currently exploring the use of these particles as actuators within ~ 100 – 400nm liposomes. While bilayer compartments are quite deformable, they pop like balloons if stretched too far (in excess of approximately 5-10%). This could give both spatial and temporal control of drug delivery from liposomes without the need for specialized liposome compositions or large scale heating of the tissue itself. The use of homing peptides on the external leaflet of the liposomes for active targeting liposomes and liposome composites will briefly be discussed as well.
3:30 PM - **FF2.4
Targeted Perfluorocarbon Nanoparticles for Diagnosis and Therapy.
Gregory Lanza 1 , Patrick Winter 1 , Shelton Caruthers 1 , Tillmann Cyrus 1 , Anne Neubauer 1 , Kathryn Partlow 1 , Anne Schmieder 1 , Samuel Wickline 1 Show Abstract
1 Medicine, Washington University Medical School, St Louis, Missouri, United States
The field of nanomedicine is quickly evolving in response to achievements in genomics, proteomics, molecular biology, bioengineering, and the imaging sciences. New approaches to entrenched medical problems are being studied using a cadre of “nanotools”, one example of which is perfluorocarbon nanoparticles.Perfluorocarbon nanoparticles represent a platform technology with nominal sizes around 250nm, which can be modified to home to thrombi and the neovasculature in vivo after intravenous injection. They can be noninvasively imaged with ultrasound, magnetic resonance (MR, 1H and 19F), or SPECT/CT. In rabbit models, perfluorocarbon nanoparticles have been demonstrated to deliver drug payloads targeted to vascular tissues for anti-angiogenic and anti-restenotic applications and to noninvasively confirm and quantify delivery as well as to follow response to treatment. In canine studies these agents have been demonstrated to target and enhance the MR and ultrasound contrast of intravascular thrombi, and using ex vivo human carotid endarterectomy sections, these results have been extrapolated to human disease where the potential for sensitive detection of microthrombi in the fissures of ruptured plaques is clearly demonstrated. The development of emerging nanotechnology platforms, such as the perfluorocarbon nanoparticles, permits translation of immunohistology techniques from fixed tissue on a slide to live tissue in an animal. These new agents allow biochemical and physiological changes to be studied dynamically in vivo and permit the quest for site-directed therapy to be realized.
4:30 PM - **FF2.5
A Lipid Tool Kit Containing Low pH Sensitive, Reversible, Stabilizing and Metal Chelation Linkers for Assembly of a Drug and Gene Delivery Liposome.
Francis Szoka 1 , Zhaohua Huang 1 , Oana Martin 1 , Weijun Li 1 , Virginia Platt 1 , Joshua Park 1 , Douglas Watson 1 , Mahmoud R. Jaafari 1 Show Abstract
1 , University of California, San Francisco, California, United States
5:00 PM - FF2.6
Applications of Magnetic Nanoparticles for the Treatment of Osteoporosis
Ganesan Balasundaram 1 , Thomas Webster 1 Show Abstract
1 , Brown University, Providence, Rhode Island, United States
5:15 PM - FF2.7
Piroxicam Entrapped In Head-Group Polymerized Liposomes Inhibits Proliferation of IC2 Mast Cells In Vitro
Anu Puri 1 , Glenn Lawson 2 , R. Shivakrupa 3 , Benitra Johnson 1 , Robert Blumenthal 1 , Alok Singh 2 Show Abstract
1 CCRNP, NCI-Frederick, NIH, Frederick, Maryland, United States, 2 Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington DC , District of Columbia, United States, 3 , Nature Publishing Group, Cambridge, Massachusetts, United States
5:30 PM - FF2.8
Heterostructured Bio-Nano Hybrids for Drug and Gene Delivery
Jin-Ho Choy 1 , Jae-Min Oh 1 , Soo-Jin Choi 1 Show Abstract
1 Nanoscience, Center for Intelligent Nano-Bio Materials, Ewha Womans Univeristy, Seoul Korea (the Republic of)
New biomolecular-inorganic nanohybrids with two different functions, one from inorganic moiety and the other from biological one were realized by soft chemical methods such as intercalation, coprecipitation and exfoliation-reassembling reactions. Recently we have been focusing on two-dimensional inorganic compounds like layered double hydroxides (LDHs), since they are biocompatible and can be used as gene or drug delivery inorganic nanovehicles. To the best of our knowledge, such inorganic drug delivery vectors are quite different from conventionally developed ones such as viral based vectors, naked DNA, biodegradable polymers,liposomes, and etc, those which are however limitedly used due to their toxicity, immunogenecity, poor integration, and etc. But we found that such disadvantages can be overcome by immobilizing genes or drug molecules into these new inorganic vectors, which consist of non-toxic metal ions with biological compatibility. Since LDHs are anion exchangeable, negatively charged functional biomolecules can be easily intercalated into hydroxide layers of LDHs by soft chemical reaction methods to form bio-LDHs nanohybrids. In such a way they can gain extra stabilization energy due to the electrostatic interaction between inorganic layers, whatever they are anionic or cationic, and counter-charged biomolecules or drugs. We also found that the hydroxide layers of LDHs could protect the intercalated molecules very efficiently. If necessary, inorganic materials, as reservoir and delivery carrier, can be intentionally removed by dissolving them in an acidic or basic media, which offer a way of recovering the encapsulated biomolecules or drugs. The possible roles of inorganic lattice as the gene and drug delivery carrier will be shown by demonstrating the cellular uptake experiments of FITC, fluorophore, with laser scanning confocal fluorescence microscopy as well as of radioactive isotope-labeled ATP-LDH hybrid. As the typical examples for gene and drug delivery systems, As-myc-LDH and MTX-LDH nanohybrids will be demonstrated along with their endocytic mechanism. In addition, nanotoxicity of LDH and other inorganic nanoparticles will be also discussed in detail.
Vincent A. Hackley National Institute of Standards and Technology
Anil K. Patri National Cancer Institute at Frederick
Judith Stein GE Global Research
Brij M. Moudgil University of Florida
FF3: Multifunctional Nanoscale Platforms for Disease Therapeutics
Wednesday AM, April 11, 2007
Room 2018 (Moscone West)
9:30 AM - **FF3.1
Multifunctional Nanoparticles with Imaging and Therapeutics Functions for Nanomedicine
Paras Prasad 1 Show Abstract
1 Chemistry, SUNY at Buffalo, Buffalo, New York, United States
Nanomedicine encompasses a vast area of biomedical research, from the development of new generation of contrast agents for diagnostic imaging to synthesizing targeted delivery vehicles of therapeutic drugs. This talk will highlight the use of multifunctional nanoparticles with combined imaging, diagnostic and therapeutic functions for nanomedicine. In our Institute we are developing new optical nanoprobes for bioimaging. They include functionalized quantum dots, aggregation-enhanced two photon dyes as well as nanocomposite nanoparticles with combined optical, magnetic, plasmonic and PET imaging capabilities. The goal is to provide targeting nanoprobes for early detection of diseases as well as for real time monitoring of a disease progression or the progress of a therapy. The organically modified silica (ORMOSIL) nanoparticles have been developed as a new-generation drug carrier for photodynamic therapy (PDT) of cancer, as well as for an efficient non-viral gene delivery, capable of transfecting neuronal cells in vivo with superior efficacy over viral vectors.
10:00 AM - **FF3.2
Multifunctional Nanosystems For Targeted Drug And Gene Delivery.
Mansoor Amiji 1 Show Abstract
1 Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States
Nanotechnology is expected to have a revolutionary impact on medical diagnosis and therapy. In cancer therapy, targeting and localized delivery are the key challenges. To wage an effective war against cancer, we have to have the ability to selectively attack the cancer cells, while saving the normal tissue from excessive burdens of drug toxicity. In this presentation, I will discuss the different nanotechnology platforms that we have developed for targeted drug and gene delivery to tumor mass. Special emphasis will be placed on nano-platforms that offer opportunities for multi-functionalization to allow for simultaneous strategic delivery of multiple therapeutic agents or combining imaging and therapeutic modalities. Results from our laboratory at Northeastern University show that polymer- and lipid-based nanosystems can provide versatile platforms for delivery of multiple therapeutic agents, specifically to enhance therapeutic effect and overcome drug resistance in cancer. In addition, polymeric nanoparticles are used for tumor-targeted anti-angiogenic gene therapy. Nanoemulsions, made from oils rich in polyunsaturated fatty acid, offer an opportunity to facilitate transport across biological barriers for targeted delivery of drugs and imaging agents. Lastly, I will discuss our work on gold and iron oxide-gold nanostructures that are functionalized for targeted imaging and drug delivery applications.
10:30 AM - FF3.3
Oligonucleotide-Modified Gold Nanoparticles for Intracellular Gene Regulation.
Dwight Seferos 1 , David Giljohann 1 4 , Nathaniel Rosi 1 , C. Thaxton 1 3 , Abigail Lytton-Jean 1 , Min Su Han 1 , Pinal Patel 1 4 , Weston Daniel 1 , Chad Mirkin 1 2 3 Show Abstract
1 Department of Chemistry, International Institute for Nanotechnology, Northwestern University, Evanston, Illinois, United States, 4 Interdepartmental Biological Sciences Program, Northwestern University, Evanston, Illinois, United States, 3 Department of Medicine, Northwestern University, Evanston, Illinois, United States, 2 Deaprtment of Materials Science and Engineering, Northwestern University, Evanston, Illinois, United States
10:45 AM - FF3.4
An Investigation of the Uptake Mechanism and Pathway of Carbon Nanotubes as Intracellular Transporters for DNA and siRNA.
Lifeng Dong 1 , Carrie Vause 2 , Sunny Qiu 3 , Charles Hendrix 2 , Paul Durham 2 Show Abstract
1 Physics, Astronomy, and Materials Science, Missouri State University, Springfield, Missouri, United States, 2 Department of Biology, Missouri State University, Springfield, Missouri, United States, 3 Greenwood Laboratory School, Missouri State University, Springfield, Missouri, United States
11:15 AM - **FF3.5
Plasmon-based Nanoparticle Probes for Multifunctional Diagnostics and Therapeutics.
Naomi Halas 1 Show Abstract
1 ECE Department, Rice University, Houston, Texas, United States
11:45 AM - **FF3.6
Dendrimer Based Nano-Containers/Scaffolding for Targeted Diagnostics and Therapies.
Donald Tomalia 1 2 , Lori Reyna 1 , Sonke Svenson 1 Show Abstract
1 , Dendritic Nanotechnologies, Inc., Mt. Pleasant, Michigan, United States, 2 Chemistry Department, Central Michigan University, Mt. Pleasant, Michigan, United States
Dendrimers are routinely synthesized as tuneable nanostructures that are designed and regulated as a function of their size, shape, surface chemistry and interior void space. They are obtained with structural control approaching that of traditional biomacromolecules such as DNA/RNA or proteins and are distinguishable by their precise nanoscale scaffolding and nano-container properties. This lecture will review progress on the use of these features for both targeted diagnostic and drug delivery applications. Recent efforts have focused on the synthesis and preclinical evaluation of a multi-purpose, STARBURST® poly(amidoamine) (PAMAM) dendrimer prototype that exhibits properties suitable for use as: (i) a targeted, diagnostic MRI contrast agent (ii) and/or for controlled delivery of cancer therapies. Special emphasis will be placed on the lead candidate, namely; (core: 1,4-diaminobutane; G=4.5); [dendri-PAMAM(CO2Na)64]. This dendritic nanostructure was selected based on a very favorable nanotoxicity profile*, the expectation that it will exhibit desirable kidney excretion properties and demonstrated targeting features.*The Nanotechnology Characterization Laboratory (NCL), an affiliate of the National Cancer Institute (NCI) has studied the lead compound and found it to be extraordinarily benign and highly biocompatible.
12:15 PM - FF3.7
Multifunctional Nanobiomedical Platforms based on Nanoparticles and Nanoporous Materials
Taeghwan Hyeon 1 2 , Jaeyun Kim 1 2 , Hyon Bin Na 1 2 , Ji Eun Lee 1 2 , Yong Il Park 1 2 , Nohyun Lee 1 2 Show Abstract
1 School of Chemical and Biological Engineering, Seoul National University, Seoul Korea (the Republic of), 2 National Creative Research Initiative Center for Oxide Nanocrystalline Materials, Seoul National University, Seoul Korea (the Republic of)
Nanotechnology offers tremendous hopes for future bio-medical technology. Clever combination of different nanoscale materials will lead to the development of multifunctional nanomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy. In this presentation, I would like to present some of our group’s recent results on the designed fabrication of multifunctional nanostructured materials based on nanoparticles and nanoporous materials and their bio-medical applications. We reported on the fabrication of monodisperse nanoparticles embedded in uniform pore-sized mesoporous silica spheres (J. Am. Chem. Soc 2006, 128, 688). The magnetic separation (guiding) was demonstrated, and they were also investigated as drug delivery carriers. We developed a simple, reproducible, and general method of preparing multifunctional nanoparticle assembled silica spheres. Magnetite nanoparticles along with other kinds of nanoparticles such as Au, CdSe/ZnS, and Pd were simultaneously assembled on 150 nm sized uniform silica spheres. These multifunctional nanoparticle assembled silica spheres are likely to find many catalytic and biomedical applications derived from their magnetic property combined with surface plasmon resonance, luminescence, and catalysis (Angew. Chem. 2006, 45, 4789). We fabricated magnetic gold nanoshells consisting of gold nanoshells (for NIR photothermal therapy) that are embedded with Fe3O4 nanoparticles (for MRI contrasting agent), and conjugated them with cancer targeting agent (for targeting) (Angew. Chem. 2006, 45, in press). Cancer cells targeted with magnetic gold nanoshells were detectable by a clinical MRI system and rapidly destroyed by exposing them to femtosecond laser pulses of NIR wavelength at a low power. We synthesized Ni/NiO core/shell nanoparticles and applied them to the selective binding and subsequent magnetic separation of histidine-tagged proteins (J. Am. Chem. Soc 2006, 128, 10658). When imidazole stabilized Ni/NiO nanoparticles were incubated with a mixture solution containing His-tagged green fluorescent protein (GFP) and normal mouse IgG labeled by Cy5, His-tagged GFP was selectively removed from the mixture. We synthesized magnetic mesocellular carbon (Mag-MCF-C) through a simple synthetic method and used for the construction of magnetically switchable bioelectrocatalytic system (Angew. Chem. 2005, 44, 7427). Glucose oxidaze immobilized in Mag-MCF-C were successfully utilized in developing a magnetically switchable bioelectrocatalytic system. We will also discuss a new T1 MRI contrast agent for neuroscience using nanoparticles.
12:30 PM - FF3.8
Transportation of Anti-cancer Agents Involving Inorganic Titania Nanotube Substrate.
Harsha Kulkarni 1 2 , Yue Wu 1 2 , Rihe Liu 3 , Baocheng Huang 3 Show Abstract
1 Curriculum in Applied and Material Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 2 Department Of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 3 School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
FF4: Preclinical Characterization of Biomedical Nanomaterials I
Wednesday PM, April 11, 2007
Room 2018 (Moscone West)
2:30 PM - **FF4.1
Characterization of Nanoscale Materials by Analytical Ultracentrifugation.
Tom Laue 1 Show Abstract
1 CAMIS, University of New Hampshire, Durham, New Hampshire, United States
3:00 PM - FF4.2
Characterization of Antibodies – in Batch and Flow.
Ulf Nobbmann 1 , Kevin Mattison 2 Show Abstract
1 , Malvern Instruments Ltd, Malvern United Kingdom, 2 , Malvern Instruments Inc, Southborough, Massachusetts, United States
Antibodies are specialized proteins that function as an essential part of the immune system and usually target specific receptors, making them ideal for the development of drug candidates. They are members of a class of proteins known as immunoglobulins, typically with a molecular size near ~10nm. This preclinical characterization shows the advantages of dynamic light scattering (DLS) both as a standalone method and in conjunction with chromatographic separation. We show data demonstrating the effect of different storage conditions and sample treatment, leading to different size distributions. Behaviour as a function of temperature shows a clear melting or aggregation point, above which the molecules assemble into larger structures. Higher melting points are correlated with higher stability.Size distribution data may be compared with results obtained from analytical ultracentrifugation (AUC) – but at much faster acquisition time of minutes instead of hours.We have also combined light scattering with chromatography to show the separation of antibodies and Fab fragments. Here, the resolving power of the separation method allows us to distinguish the fragments (about ~5nm size) from the ‘intact’ molecules.Dynamic light scattering is a versatile measurement technique and ideally suited as a metrology of choice for size and stability of nano-sized materials.
3:15 PM - FF4.3
Sizing Up Nanoparticles: Batch vs. Flow Mode.
Jeffrey Clogston 1 , Jiwen Zheng 1 , Scott McNeil 1 , Anil Patri 1 Show Abstract
1 Nanotechnology Characterization Lab, NCI-Frederick (SAIC-Frederick), Frederick, Maryland, United States
Interest in nanotechnology is rapidly growing as applications for nanoparticles in drug delivery and as image contrast agents are realized. Nanoparticles, as the name implies, refers to particles with sizes ranging from a few nanometers to hundreds of nanometers. Based on this definition, it is size which differentiates nanoparticles from all other particles. Also, it is size which will contribute to the properties of the nanoparticles and determine ultimately its function and efficacy in real-world applications. Thus it is important to properly characterize the size of nanoparticles. Light scattering (static and dynamic) is a non-invasive technique for measuring particle size and size distribution in solution. Measurements can be made in batch or flow mode. In the case of batch mode, the average size of the nanoparticle is determined. Thus if the sample contains impurities or aggregates, the size would be skewed and inaccurate. To accurately determine size, some type of separation would be needed. Size Exclusion Chromatography (SEC) is a separation technique used for determining purity of a sample and is based on the molecular size of the sample components. Coupled with a multiple angle laser light scattering (MALLS) and inline dynamic light scattering (DLS) apparatus, the size can be determined for the fractionated sample. The sizes of several different nanoparticles were measured in batch and flow mode and the implications of the size results are discussed. Nanoparticles studied include dendrimers, liposomes, and metal particles. Finally, these results are used to establish standard protocols for size characterization of nanoparticles.
3:30 PM - FF4.4
Characterization of Gold Nanoparticles In Aqueous Solution: Asymmetric-Flow Field-Flow Fractionation with MALS, PCS and UV-Vis Detection
Tae Joon Cho 1 , Jiwen Zheng 2 , Jeffrey Clogston 2 , Vincent Hackley 1 , Anil Patri 2 Show Abstract
1 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 2 , Nanotechnolgy Characterization Laboratory, SAIC Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States
Nanoparticles (NPs) are showing great promise in their utility towards biomedical applications in areas such as drug delivery, diagnostics and image contrast enhancement. The standardization of physical characterization protocols for NPs is critical for their eventual approval and use in clinical settings, and for the development of reliable nanosize reference materials. Field-flow fractionation (FFF) is emerging as a powerful tool to obtain information on the composition, size, and molecular weight of fractionated NP solutions. FFF is classified into several sub-techniques based on the applied "field", with the most common and broadly applicable being asymmetric-flow (A-FFF). A-FFF separates constituents according to their hydrodynamic size, and can be coupled with various detectors, such as UV-Vis, multi-angle light scattering (MALS), differential refractive index (DRI), photon correlation spectroscopy (PCS), fluorescence, and, more recently, inductively coupled plasma-mass spectrometry (ICP-MS). Depending on the different detector systems employed, further information such as the number and distribution of ligands or drug molecules attached to a multifunctional nanomaterial and the frequency of dimer, trimer and higher order aggregates can be obtained.In the present work we have employed commercial A-FFF systems customized with various detectors, including MALS, PCS, DRI and UV-Vis, to establish fundamental protocols for the characterization of gold nanoparticles and their bio- or dendridic-conjugates. These protocols are being applied in the development of new gold-based nanosize reference materials intended for the cancer research community. We optimized the experimental conditions by controlling various parameters, such carrier composition, membrane material, and ratios of channel-to-cross flow rates. Also, samples were separated by collection mode from A-FFF, to coincide with the MALS signal, and subsequently investigated for purity and accuracy by further supportive analysis of off-line UV-Vis and PCS measurements. We report on the results of these studies and their implications for biomedical research.NCL is funded by NCI Contract N01-CO-12400
3:45 PM - FF4.5
Absolute Size Exclusion Chromatography - Enhanced Resolution Protein Characterization
Torrey DeLuca 1 , Kevin Mattison 1 Show Abstract
1 , Malvern Instruments, Southborough, Massachusetts, United States
Size exclusion chromatography (SEC) and dynamic light scattering (DLS) are two technologies common to protein laboratories. SEC is routinely used for purification, identification, and quantification of protein mixtures, while batch DLS is routinely used for pre-column size & polydispersity measurements, along with aggregate quantification. The coupling of DLS & SEC technologies has been difficult, due in large part to the fact that eluted protein sample concentrations tend to be well below the detection limit for most dynamic light scattering instruments. As highlighted and discussed in the paper presented here however, the latest generation of DLS systems, specifically the high sensitivity Zetasizer Nano from Malvern Instruments, has proven itself capable of handling this low protein concentration challenge. As a consequence, size exclusion chromatography systems can now be directly coupled with high sensitivity DLS instrumentation, thereby providing an “absolute” measure of the hydrodynamic size and minimizing the common headaches of SEC measurements such as packing material interactions and shape effects.
4:15 PM - **FF4.6
What’s The Correct Answer – The Essentials Of DLS Measurements & Data Interpretation
Kevin Mattison 1 Show Abstract
1 , Malvern Instruments, Southborough, Massachusetts, United States
Since its market introduction roughly 30 years back, dynamic light scattering (DLS) has occupied a position of increasing popularity within the area of sub-micron particle and biopolymer characterization, due in large part to the non-invasiveness of the technique, the minimal sample volume & concentration requirements, and the quickness of data collection. Using ISO recommended measurement and analysis procedures, determination of the mean sample size and distribution width from DLS measurements is quite simple. In addition, modern instrumentation design and data interpretation software have removed much of the “mystic” traditionally associated with this somewhat complex particle sizing technology. As a consequence, DLS instruments can now be routinely found in protein and nanoparticle laboratories around the globe.As might be expected, the simplicity of modern DLS instrumentation comes with a caveat. While calculation of the mean particle size for DLS is straight forward, extraction of further information, such as the intensity and/or volume (or mass) distribution is more convoluted, requiring the use of fitting algorithms. Data interpretation can be further complicated by the presence of noise, especially for samples with physical properties that are near the specified limits of the instrument/technique. This seminar covers the dos and don’ts of DLS data interpretation, and addresses the common question of “what is the correct answer”. Topics to be covered include: 1) the basis of DLS measurements, 2) the limitation and advantages of DLS measurements with respect to nanosize particles under biologically relevant conditions, 3) common data inversion methods and how they differ, 4) comparison of DLS size results to those derived from orthogonal technologies, 5) influence of sample characteristics, such as concentration, absorption, and fluorescence on DLS results, and 6) current state of the art and instrument options.
4:45 PM - **FF4.7
Advanced Analytical Microscopy of Engineered Nanoparticle Systems.
John Henry Scott 1 Show Abstract
1 , NIST, Gaithersburg, Maryland, United States
To address the needs of a wide variety of potential application domains, the sophistication and structural complexity of engineered nanoparticle systems has been steadily increasing. Often the unique functionality of these systems depends on the 3-dimensional distribution of multiple phases, ranging from simple coatings to core-shell morphologies to multifunctionalizations for drug delivery. This need for controlled 3-dimensional chemical heterogeneity at the nanoscale presents significant challenges both for the nanomanufacturing of these materials and their metrology and characterization. Even when the nanoparticles have relatively simple structures, the demands of modern process control methodologies and the specifications of end users frequently require increased metrology precision and decreased measurement bias for critical measurands such as coating thicknesses or particle size distributions. Recent advances in electron microscopy and focused ion beam (FIB) technology provide powerful tools for the 3-dimensional structural and elemental characterization of nanomaterials. Dimensional metrology using phase contrast high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) can measure the physical dimensions of nanostructures at the single nanometer level. Elemental mapping using energy-filtered TEM (EFTEM) can be used to map the spatial distribution of different stoichiometries, while electron tomography can reconstruct the 3-dimensional morphology of nanoparticle assemblies. Examples of the above techniques will be presented along with recent NIST efforts to fuse these techniques into a methodology for 3-dimensional chemical imaging of engineered nanostructures.
5:15 PM - FF4.8
Dielectric Relaxation and Dynamic Light Scattering Study of a Liposome in the Aqueous Solution.
Shyamal Kundu 1 , Song gi Choe 1 , Wataru Yamamoto 1 , Rio Kita 1 , Shin Yagihara 1 Show Abstract
1 Department of Physics, Tokai University, Hiratsuka, Kanagawa, Japan
5:30 PM - FF4.9
AFM Metrology for Nanoparticle & Nanostructures Characterization: Visualization, Morphology Quantitation and Probe Artifacts.
Natasha Starostina 1 , Paul West 1 Show Abstract
1 R&D, PacificNanotechnology Inc., Irvine, California, United States
5:45 PM - FF4.10
Analysis of Nanoparticles in Serum by Capillary Electrophoresis.
King Chan 1 , Anil Patri 2 , Timothy Veenstra 1 , Scott McNeil 2 , Haleem Issaq 1 Show Abstract
1 Laboratory of Proteomics and Analytical Technologies, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States, 2 Nanotechnology Characterization Laboratory, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States
The last decade witnessed an increasing interest in using nanoparticles as clinical tools for the delivery of drugs to specific targets. As a result there is a need to develop assays capable of qualitatively and quantitatively determine their presence in biological fluids and tissue. In this study, we developed a capillary electrophoresis approach to analyze two nanoparticles: carboxyfullerene (C3) and dendrofullerene (DF) in both standard solutions and a serum matrix. These highly soluble, charged C60 derivatives were characterized by capillary zone electrophoresis (CZE) using either a bare or dynamically coated fused-silica capillaries. The resolution of both nanoparticles was slightly lower with the coated capillary, however, their migration times were faster. The quantitation of the particles was linear from 0-500 µg/ml with quantitation limits ranging from 0.6 to 6 µg/ml. In this presentation different CE approaches will be discussed and commented upon.ACKNOWLEDGEMENTFunded by NCI Contract N01-CO-12400
FF5: Poster Session: Nanoscale Materials for Imaging, Diagnostics and Therapeutics
Tae Joon Cho
Thursday AM, April 12, 2007
Salon Level (Marriott)
9:00 PM - FF5.1
TEM Observations of Bio-Conjugated Streptavidin-Gold Nanoparticles.
Ai Leen Koh 1 2 , Robert Sinclair 1 Show Abstract
1 Materials Science and Engineering, Stanford University, Stanford, California, United States, 2 Mechanical Engineering, Stanford University, Stanford, California, United States
Biological applications of nanoparticles require that they be functionalized with a biocompatible coating so that they can be conjugated to specific antibodies or proteins of interest. Streptavidin is a protein that is commonly used for this purpose. Its highly specific interaction with the small vitamin biotin allows localization of the conjugated sites, which can have potential applications in areas such as protein targeting and clinical diagnostics. The Transmission Electron Microscope (TEM) is a powerful tool for studying nanoparticles owing to its sub-nanometer resolution. However, TEM imaging of bio-functionalized nanoparticles poses several challenges. First of all, bio-molecules are composed of light elements which do not scatter electrons sufficiently and hence do not produce contrast. Furthermore, biological specimens may be destroyed by the electron beam very rapidly. These issues can be overcome by using the method of negative staining, where electron dense material is introduced onto the specimen to enhance contrast. Using this method, streptavidin-functionalized gold nanoparticles were stained using Phosphotungstic Acid (PTA) at pH 7.0 and were observed using the TEM. The streptavidin proteins appear as light regions/halos surrounding the gold nanoparticles. The widths of the halos are similar to those of streptavidin protein molecules reported. Experiments were performed to conjugate 5nm streptavidin-gold nanoparticles to biotinylated antibodies and proteins, and then negatively staining the samples with PTA for TEM analyses. The bio-conjugation experiment showed an increase in halo lengths in more than 60% of the particles observed. The second experiment involved binding the streptavidin-gold nanoparticles to biotinylated actin, a cytoskeletal protein responsible for the contractile property of muscles and other cells. In this experiment, the nanoparticles were localized around the long actin filaments. Negative staining allows inorganic nanoparticles and their organic coating to be observed simultaneously under the TEM.
9:00 PM - FF5.10
The Use Of Modified Dendrons As Non Viral Vectors For Gene Therapy.
Simon Jones 1 , David Smith 1 Show Abstract
1 Chemistry, University of York, York United Kingdom
There is intense current interest in the development of vectors for the delivery of genetic materials into cells.1 Synthetic vectors have emerged as a genuine alternative to viral vectors with their lower toxicity and ability to carry large amounts of DNA. Recently, Smith et al. showed that dendritic arrays of spermine groups, nature’s own DNA binder, could condense DNA into nanometre sized with high affinity.2 However, transfection studies indicated modest gene delivery profiles.3With the goal of enhancing the ability of these dendrons to act as vectors, we have now designed and synthesised a series of dendrons with varying numbers of aliphatic tails and cholesterol moieties attached as well as different polyamine surface groups. Binding strengths of this new family of dendrons was determined using ethidium bromide displacement assays and complex size was obtained with TEM studies.References: 1.T. Merdan, J. Kopecek, T. Kissel, Adv. Drug Del. Rev. 2002, 54, 715-7582.M. A. Kostiainen, J. G. Hardy, D. K. Smith, Angew. Chem. Int. Ed. 2005, 44, 2556-25593.M. A. Kostiainen, J. G. Hardy, D. K. Smith, D. W. Pack, N. Gabrielson, Bioconjugate Chemistry, 2006, 17, 172-178.
9:00 PM - FF5.11
Micelles Based on Poly(L-glutamic acid)-b-Polylactidewith Paramagnetic Gd Ions Chelated to Shell Layer
Guodong Zhang 1 , Chun Li 1 Show Abstract
1 Experimental Diagnostic Imaging, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States
There is much interest in nanoscaled contrast agents for cellular and molecular MR imaging. MRI has excellent spatial resolution but relatively low sensitivity. Development of nanoparticulate carriers containing a high payload of Gd complex is a promising approach to achieve high sensitivity. Here we report on the successful fabrication of nanoscaled micelles based on poly(L-glutamic acid)-b-polylactide [poly(L-glutamic acid)-b-PLA] block copolymer with paramagnetic Gd ions chelated to their shell. The copolymer poly(L-benzyl glutamate) (PBGL)-b-PLA, precursor of poly(L-glutamic acid)-b-PLA, was first prepared by sequential ring-opening polymerizations. Anionic polymerization of L-lactide with N-Boc-ethanolamine as the initiator in the presence of nephthalene/potassium, followed by removal of t-Boc protecting group yielded PLA with a terminal amino group (NH2-PLA). Subsequent ring-opening polymerization of g-Bzl-L-Glu-NCA with NH2-PLA gave PBGL-b-PLA. After removal of benzyl groups in PBGL block, p-aminobenzyldiethylenetriaminepenta(acetic acid) (DTPA) was conjugated to the side chain carboxylic acid groups of poly(L-glutamic acid). Nanoscaled micelle was formed from poly(L-glutamic acid)(DTPA)-b-PLA using the dialysis method. Finally, Gd ions was chelated to the resulting micelles followed by extensive dialysis. The size of Gd-chelated micelles was characterized by dynamic light scattering and transmission electron microscopy (TEM). The average diameter of spherical micelle containing 5% (w/w) Gd was about 210 nm in aqueous solution, and its critical micelle concentration (CMC) was 0.06 mg/mL, determined by a fluorescence method using pyrene as the hydrophobic probe. The micelle structure was furthermore confirmed by 1H-NMR, which showed the disappearance of proton peaks from PLA segment due to the formation of hydrophobic core consisting of PLA chains. Importantly, the nanoparticles exhibited large spin-lattice relaxivity. Our data suggest that biodegradable micelles based on poly(L-glutamic acid)(DTPA-Gd)-b-PLA may be a suitable platform for the development of targeted MR imaging agents.
9:00 PM - FF5.12
Immunotargeting of MHC Class II-Expressing Cells Using γ-Fe2O3 Nanoparticle MR Contrast Agents
Kristi Hultman 1 , Adrienne Grzenda 2 , Anthony Raffo 3 , Paul Harris 3 , Stephen O'Brien 1 , Truman Brown 4 Show Abstract
1 Applied Physics, Columbia University, New York, New York, United States, 2 Surgery, Columbia University, New York, New York, United States, 3 Medicine-Oncology, Columbia University, New York, New York, United States, 4 Biomedical Engineering and Radiology, Columbia University, New York, New York, United States
The ability to non-invasively detect specific cells in the body would be an invaluable diagnostic tool. The superparamagnetic characteristics and minimal toxicity of γ-Fe2O3 nanoparticles make them an excellent candidate for use as an MR contrast agent. We have developed a technique that allows us to produce a nanoparticle-antibody contrast agent capable of targeting specific cells in concentrations detectable by MR imaging techniques using highly uniform, monodisperse γ-Fe2O3 nanoparticles, a mixture of several types of mPEG phospholipids and modified antibodies. The nanoparticle contrast agent has a plasma lifetime of approximately 3 hours in the rat, which is not significantly affected by the conjugation of antibodies or proteins. This method of conjugation is independent of the specificity of the antibody or protein, allowing us to substitute a wide range antibodies or proteins using the same basic procedure. We are currently utilizing an MHC Class II antibody, which targets antigens expressed on the surface of cells in distress, for the visualization of inflamed tissue in disease model rats.
9:00 PM - FF5.13
Development Of Polymeric Micro/Nanostructures For Gene Delivery.
Kenneth Gonsalves 1 , Dania Alyounes 1 , Christopher Yengo 2 , Qi Lu 3 , Tim Doran 3 , Yang Liu 1 Show Abstract
1 Department of Chemistry , Polymer Chemistry Nanotechnology Laboratory, Center of Optoelectronic and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina, United States, 2 Department of Biology , University of North Carolina at Charlotte, Charlotte, North Carolina, United States, 3 , Carolinas Medical Center, Charlotte, North Carolina, United States
Muscular dystrophies are a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles that control movement Gene therapy for muscular dystrophy has attracted increasing interest over the past decade. A form of therapy is gene delivery to the mutated cell. As of now, the most effective gene delivery method is the viral vector, specifically rAAV-mediated delivery system. However, this delivery method revealed several problems in clinical trials such as disruption of proper gene functions. Also the viral vector produced toxicity caused devastating immune and inflammatory responses. Moreover, it was difficult to produce large quantity of clinical grade virus.The objective of this project is to develop an alternative delivery method where Pluronic® polymers and their analogs are used for binding to plasmid DNA. Here, the polymer molecules improve transgene delivery by binding to the negatively charged DNA to form a lipoplex complex. The lipoplex complexes were analyzed using fluorescence techniques, zeta potential, and light scattering analysis. Initially, varying families of 20 pluronics of polyethyleneglycol co-polypropalyneglycol polyurethane were combined with the plasmid DNA and screened for binding affinity. Pluronics of the highest binding affinity to plasmid DNA were then identified and their structures were used in a series of improvement studies. The improvements included introducing a charge to the formally dipole structure by adding a urethane linkage between building block structures. Next, a combinatorial array was made for these polymer and their derivatives and fluorescence measurements were taken to relate molecular weight of to binding affinity. Also, surface charge analyses were made to observe the effect of the charge on the binding. Zeta potential was also used in the purpose of confirming binding activities between the DNA and the polymer. Further studies and tests were also preformed on several molecules that resemble the characteristics of the Pluronic but vary in their electrostatic forces. These data along with analyses of the binding characteristics of the lipoplexes, in conjunction with their gene delivery abilities will be presented.
9:00 PM - FF5.14
A Nanoscale Immunoassay Device for Electrical Detection of Protein Biomarkers
Kondama Reddy Ravi Kiran 1 , Sujata Iyer 2 , Shalini Prasad 1 Show Abstract
1 Electrical and Computer Engineering, Portland State University, Portland, Oregon, United States, 2 Advanced Technology Group, BD Biosciences, San Jose, California, United States
Traditional Immunoassay techniques such as Enzyme Linked Immunosorbent Assay (ELISA) techniques for detecting and quantifying biomarkers for diagnostic applications are limited by the detection turnaround time and sensitivity due to denaturization of the protein during the wash cycles. We have developed a nano-well technique to improve the sensitivity and reduce the turnaround time by employing nanoscale fabrication methods with electrical detection process. The device prototype comprises of a high-density array of nanowells that are formed by integrating a nanoporous alumina template with a microfabricated base platform. The alumina template is fabricated using the two step anodization technique. The physical dimensions of the template: diameter of the pore, pore density and pore depth can be varied depending on the application. The nanoporous structure is embedded onto a microfabricated platform comprising of microscale gold electrodes. This results in the formation of nanowells with a pico liter volume. The nanowells are “loaded” with the antibodies and the electrochemical signal changes on the gold electrodes are mapped with the addition of the antigen. The formation of the immuno-complex results in the modulation of the electrical double layer at the junction of the antibody binding site and the gold electrode. These interactions at the nanoscale are expected to improve the sensitivity.
9:00 PM - FF5.18
Rapid Release of Liposomal Short Chain C6-Ceramide In Vivo
Banu Zolnik 1 , Scott McNeil 1 , Stephan Stern 1 Show Abstract
1 Nanotechnology Characterization Laboratory , SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States
Ceramide is an endogenous sphingolipid that appears to be involved in cell cycle and apoptosis signaling. Studies of ceramide in vitro have demonstrated antineoplastic activity. However, the chemotherapeutic utility of ceramide in vivo is limited by its hydrophobic nature. To overcome this solubility issue, liposomal delivery systems have been utilized in animal models. The objective of this study was to characterize the pharmacokinetics and tissue distribution of a C6-ceramide liposome system in rats, using 14C-ceramide and 3H-phospholipid as tracers of the ceramide and liposome components, respectively. Ceramide liposomes were administered at 15 mg/kg by jugular vein to female SD rats. The apparent volume of distribution (Vapp) determined by noncompartmental analysis was 50 ml/kg, suggesting that liposome was confined to the plasma volume. By contrast, the Vapp of ceramide was 20 fold higher than that of liposome. This high Vapp of ceramide in relation to liposome indicates the ceramide-liposome interaction is short-lived, and approximately 95% of the encapsulated ceramide was released immediately upon injection. Plasma half-life of ceramide was similar to that of liposome (20 vs.14 h), and the area under the curve of ceramide was 80 µg*hr/mL. Ceramide disposition could not be accounted for by distribution to major organs or renal clearance. Previous in vitro studies suggest a rapid bilayer exchange mechanism for release of short chain ceramide from liposome formulations, which may explain the rapid distribution of ceramide in vivo independent of liposome. Funded by NCI Contract N01-CO-12400
9:00 PM - FF5.19
The Studies of Cytotoxicity and Transfection Efficiency of the Functionalized Gold Nanorods
Chiung Wen Kuo 1 , Peilin Chen 1 Show Abstract
1 Research Center for Applied Sciences, Academia Sinica, Taipei Taiwan
9:00 PM - FF5.2
Fluorescent Ceramic NanoProbes.
Timothy Lambert 1 , Bernadette Hernandez-Sanchez 1 , Timothy Boyle 1 , Harry Pratt 1 , Nicholas Andrews 2 , Diane Lidke 2 , Janet Oliver 2 , Bridget Wilson 2 Show Abstract
1 Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico, United States, 2 Department of Pathology, University of New Mexico, Albuquerque, New Mexico, United States
In an effort to develop new non-cytotoxic luminescent colloidal nanocrystals (NCs) for live cell imaging, we have initiated a NIH-funded program to prepare and evaluate new nanoprobes based on naturally occurring fluorescent (NOF) minerals and lanthanide-doped ceramic oxides. The major goals are to develop new probes that are highly fluorescent, bio-compatible, non-toxic, and tunable and to demonstrate their use in live cell imaging. With this in mind we have prepared sphalerite [(Fe/Zn)S], scheelite [Ca(WO4)], manganoan [(Mn/Ca)CO3] and perovskite (ATiO3, where A =Ca, Sr, Ba) inspired nanomaterials and lanthanide (Dy, Nd, Eu, Tb, Er) doped ceramic oxide nanomaterials, utilizing solution precipitation and solvothermal methods. Sphalerite, scheelite, manganoan, nanomaterials were prepared via two/three component reactions (ex. a three component reaction of [Fe(Mes)2]2, [Zn(Et)(ONep)(py)]2, and elemental S for sphalerite) while perovskite materials where generated from three new alkaline earth titanium single source alkoxide precursors (ATi2(ONep)10(py)2; where A = Ca, Sr or Ba). Lanthanide doped zinc oxides were prepared by incorporating the appropriate lanthanide amides or alkoxide into the reaction mixture. Surface capping of the prepared nanocrystals with functionalized poly(ethyleneglycol) moieties has yielded water soluble NCs that are currently being evaluated for their luminescent properties, as well as their non-toxicity and ability to report on cell-signaling events with various cell lines. The synthesis, materials characterization, water-solubilization methods, biocompatibility and cell-signaling efforts to date will be presented.This work was supported by the National Institutes of Health, through the NIH Roadmap for Medical Research (Grant #1 R21 EB005365-01) and by the United States Department of Energy. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
9:00 PM - FF5.20
Virus Templated Noble Metal Nonorods for Cancer Therapies.
Ju Taek Nam 1 Show Abstract
1 chemistry, POSTECH, Namgu, Pohang Korea (the Republic of)
9:00 PM - FF5.21
Measuring Nanotube Length and Bundle Number using Dynamic Light Scattering.
Malcolm Connah 2 , Michael Kaszuba 2 , Kevin Mattison 1 Show Abstract
2 , Malvern Instruments, Malvern United Kingdom, 1 , Malvern Instruments, Southborough, Massachusetts, United States
9:00 PM - FF5.22
Photocatalytic Effects of TiO2 Nanoparticles for Skin Cancer Cell Treatments
Jung-wook Seo 1 3 , Heawon Cheung 3 1 , Mi-yun Kim 1 3 , Junggi Lee 2 3 , In-hong Choi 2 3 , Jinwoo Cheon 1 3 Show Abstract
1 Chemistry, Yonsei university, Seoul Korea (the Republic of), 3 Nano-medical Core Research Center, Yonsei university, Seoul Korea (the Republic of), 2 Microbiology, Yonsei University, Seoul Korea (the Republic of)
The photocatalytic activity of TiO2 highly depends on several parameters including surface area, crystalline phase, and single crystallinity. Although there have been reports of high quality TiO2 nanoparticles fabricated via non-hydrolytic methods, these are not soluble in aqueous medium and their utilization toward biological applications is rare. Here, we describe the fabrication of water soluble and biocompatible TiO2 nanoparticles which possess excellent size monodispersity, single crystallinity, and highly desired anatase phase. Our water soluble TiO2 nanoparticles are biocompatible, but upon UV irradiation, clearly show highly enhanced photocatalytic effects for skin cancer cell (melanoma cell line: A-375) treatments compared to commercially available Degussa P-25 TiO2 nanoparticles.
9:00 PM - FF5.23
Synthesis of Water-soluble Silicon Nanoparticles for Biological Imaging
Xiaoming Zhang 1 , Angelique Louie 1 , Susan Kauzlarich 2 Show Abstract
1 Department of Biomedical Engineering, University of California, Davis, California, United States, 2 Department of Chemistry, University of California, Davis, California, United States
9:00 PM - FF5.3
Heterodimer Structured FePt-Au Nanocrystal with Multi-functionalities.
Jin-sil Choi 1 , Seung-won Park 1 , Sang-mi Choi 1 , Young-wook Jun 1 , Soo-In Yeon 2 , Jun-su Shin 2 , Jinwoo Cheon 1 Show Abstract
1 Department of Chemistry, Yonsei University , Seoul Korea (the Republic of), 2 Department of Microbiology, College of Medicine, Yonsei University, Seoul Korea (the Republic of)
9:00 PM - FF5.4
Hybrid Atomic Force Microscopy and Near-Field Scanning Optical Microscopy Imaging of Normal and Cancer Breast Cell Endocytosis Study with Superparamagnetic Iron Oxide Nanoparticles
Yu Zhang 1 , Mihri Ozkan 1 , Cengiz Ozkan 1 , Vahid Yazdanpanah 1 , Chao Yang Liu 1 , Nathaniel Portney 1 Show Abstract
1 , UC, Riverside, Riverside, California, United States
Superparamagnetic iron oxide nanoparticles have been widely studied for their potential applications in a variety of biomedical fields including targeted drug delivery, magnetic resonance imaging (MRI) enhancing contrast agents, cell labeling, hyperthermia therapy and diagnostic assays. In cancer research, understanding and controlling iron oxide nanoparicles recognition and capture by specific cells and tissues is crucial to their use in cancer detection, diagnosis and treatment. By using a hybrid atomic force microscopy/nearfield scanning optical microscopy (AFM/NSOM) system, we investigated the endocytosis of iron oxide nanoparticles in both normal breast cells (MCF10A) and cancer breast cells (MCF7) for different incubation time. This hybrid system simultaneous recorded topographical and near-field images, which enables to get complementary information in both morphology and optical analyses of the cellular interior. The resolution of images is observed to be very close to the size of tip. We used both tapping and contact AFM modes and transmission and reflection NSOM modes to visualize the iron oxide nanoparticles cellular interaction with normal and cancer breast cells. For both cell types, the iron oxide nanoparticles without targeting agents were observed to be actively uptaked by a two-step endocytosis process: a first step of binding at the cell membrane and then followed by a subsequent internalization. Vesicles are formed to transport iron oxide nanoparticles inside and outside the cells.
9:00 PM - FF5.5
Electrokinetic Formation of ``MicroBridges" for Rapid Detection Of Proteins.
Vindhya Kunduru 1 Show Abstract
1 Electrical & Computer Engg , Portland State University, Portland, Oregon, United States
9:00 PM - FF5.6
Active Polymer Nanoparticles: Delivery of Antibiotics.
Monica Rabinovich 1 , Rajeev Pillai 1 , Kenneth Gonsalves 1 , Michael Hudson 2 , Shankari Somayaji 2 , Kent Ellington 3 , James Horton 3 , Michael Bosse 3 Show Abstract
1 Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina, United States, 2 Department of Biology , University of North Carolina at Charlotte, Charlotte, North Carolina, United States, 3 , Carolinas Medical Center, Charlotte, North Carolina, United States
9:00 PM - FF5.7
Multi-Functional Gold Nanoshell with Superparamagnetic Iron Oxide Cores for Both MR Imaging and Photo-Thermotherapy
Xiaojun Ji 1 , Ruping Shao 1 , Emilio Esparza 1 , Gan Liang 2 , Chun Li 1 Show Abstract
1 Experimental Diagnostic Imaging, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States, 2 Department of Physics, Sam Houston State University, Huntsville, Texas, United States
The synthesis, characterization, and use of a hybrid type of nanoparticles with superparamagnetic iron oxide (SPIO) core and a gold nanoshell (NS) were described in the current investigation. This multi-functional nanoparticulate material, designed as SPIO@Au NSs, displayed superparamagnetic characteristics and a significant absorbance in the near-infrared (NIR) region of the electromagnetic spectrum. In addition, they exhibited significant spin-spin relaxivity r2 and r2/r1 values and therefore, could be imaged by MRI to obtain T2-weighted images. Moreover, SPIO@Au NSs showed efficient photo-thermal effect when exposed to NIR light. The combination of unique magnetic and optical properties of SPIO@Au NSs should enhance the efficacy of nanoshells-mediated photo-thermal therapy by directing more nanoparticles to the tumors through the use of external magnetic field, and by in vivo MRI imaging to monitor in real time the distribution of the nanoparticles before, during, and after photo-thermal therapy.
Vincent A. Hackley National Institute of Standards and Technology
Anil K. Patri National Cancer Institute at Frederick
Judith Stein GE Global Research
Brij M. Moudgil University of Florida
FF6: Preclinical Characterization of Biomedical Nanomaterials II
Thursday AM, April 12, 2007
Room 2018 (Moscone West)
9:30 AM - **FF6.1
The Nanoparticle-Biological Agent Complex: Characterizing and Manipulating the Nano-Bio Interface.
Vicki Colvin 1 Show Abstract
1 , Rice University, Houston, Texas, United States
Semiconductor, metal and ceramic nanocrystals have optical, magnetic and chemical properties that can be radically different from molecular or bulk systems. These unique and tunable features can be leveraged in biomedical applications. As an introduction we will give several examples in which such systems have been used to improve the diagnosis, imaging, and treatment of disease. Then we will discuss both the synthetic and analytical challenges with forming these materials for problems in medicine. We will first present general techniques for imparting water solubility to nanocrystals using amphilphilic co-polymers. Our strategy uses as a starting point high quality nanocrystals that are best formed in organic solvents. We then transfer the materials to water using copolymers generated using a maleic anhydride coupling scheme that permits the coupling of a wide variety of PEG polymers, both unfunctionalized and functionalized, to hydrophobic tails. The hydrodynamic size and concentration of the nanoparticle-polymer complexes requires new techniques, including size-exclusion chromatography, cryogenic transmission electron microscopy and mass spectroscopy. Ultimately, many of the key features of the nanoparticles are defined by their specific and non-specific interactions with biomolecules in complex biological fluids. Characterization of this full ‘nanocrystal-polymer-biomolecule’ complex requires additional methods drawn from both biochemistry and cell biology. In particular, we find analytical ultracentrifugation to be ideally suited for quantitative evaluation of these systems.
10:00 AM - FF6.2
High-resolution Ultra-high Frequency Acoustic Bio-microscopy Technique for Non-invasive Studies of Cells and Bio-materials.
Daniel Wulin 1 , Shriram Ramanathan 2 Show Abstract
1 Department of Physics, Columbia University, New York, New York, United States, 2 Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States
10:15 AM - FF6.3
Electrophoretic Characterization of Particles under Biological Conditions: Analysis of Cells and Viruses.
David Fairhurst 1 , Robert Rowell 2 , Robin Shattock 3 , Fraser McNeil-Watson 4 , Anastasia Morfesis 5 Show Abstract
1 , International Partnership for Microbicides, Silver Spring, Maryland, United States, 2 , University of Massachusetts, Amherst, Massachusetts, United States, 3 , St Georges Hospital Medical School, London United Kingdom, 4 , Malvern Instruments Ltd., Malvern United Kingdom, 5 , Malvern Instruments Inc., Southborough, Massachusetts, United States
One proposed approach to reduce the spread of HIV is to prevent transmission of the virus through the use of a topical microbicide. One microbicide strategy is a charge inhibition based approach using polyanionic compounds designed to interfere with the process of HIV-1 attachment to potential target cells. This strategy however, is predicated on further understanding the charge characteristics of whole virions and the relative contribution of viral and host-cell proteins to such charge. Electrokinetic methods (i.e. ζ-potential) provide information on the surface structure of biological cells without producing significant alteration of the cellular organization. Electrophoretic fingerprinting (EF) is obtained from 3D templates of the mean electrophoretic mobility (the raw data from which ζ-potential is calculated) of a given particle versus pH and solution conductivity at a fixed temperature. The EF thus represents a surface, described by isomobility lines, over all pertinent electrochemical conditions. These initial electrophoretic analyses have been performed using human CD4+ T cell lines. The cell lines are derived from human white blood cells which are the principle targets of the HIV-1 virus. Tissue culture work was carried out under Class II aseptic conditions. Cell types were maintained in RPMI growth medium supplemented with 10% heat inactivated foetal calf serum, 2mM glutamine, 100 i.u./ml penicillin and 100 μg/ml streptomycin at 37°C in a humidified 5% CO2 incubator. The cells were routinely passaged every 3-4 days in 75 cm3 fillter cap tissue culture flasks, by the addition of 4 mls of cells to 16 mls of fresh growth medium.Electrophoretic mobility (ζ-potential) was measured as a function of pH and ionic strength over a range chosen to cover that known for fluids found in the lower female reproductive tract, including vaginal fluid and semen. Measurements were made using a Malvern ZetaSizer NanoZS operating in the fast field reversal mode (PALS). Data was analyzed using SURFER™ software and the results validated from the covariance matrix of the linear fit. Challenges in the measurement and characterization of the cells include the difficulty of the cell preparation, cleanliness of the samples and sample handling required to maintain cell vitality.Overall, the EF’s analyzed under environments characteristic of physiological conditions for each CD4 T cell line resulted in similar zwitterionic surface charge features. These results suggest that the best candidate for a microbicide active needs, itself, to be zwitterionic so as to be able to mirror-image the shift in sign of surface charge as the pH of the vaginal tract changes. Current results suggest that HIV interaction with target cells is enhanced by physiological fluids. The data provides core information on the physico-chemical properties of model cellular targets for HIV-1 infection and pave the way for rational development of charge-based intervention strategies.
10:30 AM - FF6.4
Cell Response and Tissue Scaffold Triggers Investigated by Scanning Probe Recognition Microscopy.
Qian Chen 1 , Yuan Fan 1 , Shiva Arun-Kumar 1 , Andrew Baczewski 1 , Lalita Udpa 1 , Virginia Ayres 1 , Arvin Rice 2 Show Abstract
1 , Michigan State University, Lansing, Michigan, United States, 2 , Veeco Metrology Group, Santa Barbara, California, United States
Tissue scaffolds that enable the entrained re-growth of cells into damaged areas are of great medical importance. Sophisticated tissue scaffolds with properties designed for the re-growth of specific cells types, while maintaining maximum biocompatibility, would greatly increase the quality and number of applications. Such development requires understanding the tissue scaffold properties from the macromolecular perspective of cellular receptors and actuators. In a situation that reproduces its natural biological environment, a cell will extend protrusions towards the scaffold, attach to it, live and reproduce. The initial step, attachment, is triggered through a complex interaction of receptors at the leading edge of the protrusion with the external environment ahead, and with the cell internal environment behind. Much fundamental understanding is needed to design scaffolds with the most appropriate mechanical, topographical and chemical patterns that trigger attachment for particular cells or cell classes.Scanning Probe Recognition Microscopy is a new technique which allows us to adaptively follow, and multiply and repetitively investigate properties, along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected and combined. Cell sensing of rigidity (elasticity), curvature, and surface roughness are all known to trigger cell responses. Using Scanning Probe Recognition Microscopy, we investigate these multiple properties. Tissue scaffold elasticity is investigated using the Force Integration to Equal Limits mapping method to produce a robust measurement of relative elasticity. Curvature is investigated through measurements with slope-based automated tracking optimization, augmented by deconvolution, to include tip-shape broadening and angle-dependence. Confidence maps are developed to determine reliable data as a function of curvature. Independent scanning and transmission electron microscopy diameter measurements are also used as checks. Surface roughness is investigated using a mapping technique developed by our group, in which the roughness is calculated within a user-defined local neighborhood region of each current pixel, entirely within the nanofiber boundaries. Data fusion techniques are then utilized to combine reliable mechanical, topographical and curvature information into a composite picture more nearly like a cell’s perception of its environment. Emerging composite nanoscale patterns are explored, and the in-vitro responses of different cell types to different tissue scaffold characteristics are investigated.
10:45 AM - FF6.5
Stability Examination of PEG Bound to Gold Nanoparticles.
Jiwen Zheng 1 , Jeffrey Clogston 1 , Scott McNeil 1 , Anil Patri 1 Show Abstract
1 Nanotechnology Characterization Lab, National Cancer Institute, Frederick, Maryland, United States
Gold nanoparticles have shown great promise in a variety of biological applications including the use in highly sensitive diagnostic assays 1,2, thermal ablation 3, radiotherapy enhancement 4, as well as drug and gene delivery 5. Such gold particles, however, suffer from losing or reducing sensitivity and selectivity due to aggregation under high ion strength of biological fluids and non-specific interaction with biomolecules, such as proteins or DNA. Poly ethylene glycol (PEG), which is known to lengthen the circulation time of biomedicines in the bloodstream, reducing the non-specific binding of proteins, and increasing efficacy and tolerability, is currently used as coating for different kind of nanoparticles to improve their stability and biocompatibility. The currently used strategy was to attach PEG moelcucles to gold nanoparticle through Au-SH chemical bonding. There is no available information, however, about how the length, conformation and attachment sites of PEG moiety affect the binding stability on gold nanoparticles, which play such critical role in retaining the solubility, while facilitating both selectivity and reactivity. In our present work we examined the stability of thiolated PEG with different length and multi-thiol anchors bound to gold nanoparticle by an assay of PEG displacement with different moities including di-thiolthreitol (DTT) and mercaptoethanol. Dynamic light scattering (DLS), Atomic force microscopy (AFM), multiangle-laser light scattering (MALS) incorporated with refractive index (RI), UV and DLS detectors were employed to characterize size, geometry, and packing density of PEG. This information will enable us to understand, optimize and control their efficacy and distribution of gold nanoparticle-based diagnostic or therapeutic agents under complex physiological environments. 1 Tkachenko, A.G.; Xie, H.; Coleman, D.; Glomm, W.; Ryan, J.; Anderson, M.F.; Franzen, S.; Feldheim, D.L. J.Am. Chem. Soc.2003,125,4700.2 Nam, J.M.; Thxton, C.S.; Mirkin, C.A.; Science 2003, 301, 1884.3 Loo, C.; Lowery, A.; Halas, N.; West, J.; Drezek, R. Nano. Lett. 2005, 5, 709.4 Hainfeld, J.F.; Slatkin, D.N.; Smilowitz, H.M.; Phys. Med. Biol. 2004, 49, N309.5 Thomas, M.; Klibanov, A.; Proc. Natl. Acad. Sci. USA 2003, 100, 9138.
11:30 AM - **FF6.6
Physicochemical Characteristics of Nanoparticles that Affect Cellular and Tissue Responses.
Alison Elder 1 Show Abstract
1 Department of Environmental Medicine, University of Rochester, Rochester, New York, United States
Manipulation of the physicochemical properties of materials at the nanoscale has the potential to revolutionize electronic, diagnostic, and therapeutic applications. Because of the potential large-scale use of nanomaterials, it is important to determine if there is any unique toxicity of the nanoscale materials as compared to the bulk. It is essential for the purposes of interpreting results from cell culture and animal models that the nanomaterials are thoroughly characterized and that correlations are made between observed toxicological responses and the physicochemical characteristics of the materials. We hypothesize that nanomaterials by virtue of their size and surface activity can induce oxidative stress following exposures in cells or tissues and that they can move beyond the site of original deposition. To test this hypothesis, we use acellular assays (e.g. reactive oxygen species; dissolution; agglomeration analyses) to both identify potential benchmark nanomaterials and to predict responses in cells or tissues. Using in vitro (lung epithelial, endothelial cells) and in vivo assay systems, we have characterized responses, including cellular uptake and tissue distribution, of nanomaterials as a function of shape (using Pt), surface coating (using semiconductor quantum dots), size, and chemical composition. From these studies, it is clear that a dose metric other than mass is required to accurately predict response in acellular, in vitro, or in vivo systems and that surface area is a better predictor, at least within a given particle type. Other factors contribute to reactivity, though, including crystal phase, chemical composition, mode of synthesis, surface coating, and agglomeration state.
12:00 PM - FF6.7
Preclinical Immunological Testing of Engineered Nanoparticles: Regulatory and Methodological Challenges.
Marina Dobrovolskaia 1 , Scott McNeil 1 Show Abstract
1 Nanotechnology Characterization Lab, SAIC-Frederick Inc, Frederick, Maryland, United States
12:15 PM - FF6.8
Studies on the Toxicology of Engineered Nanoscale Materials.
Barbara Tarasevich 1 , Brian Thrall 2 , Jon Jacobs 2 , Justin Teeguarden 2 , Galya Orr 2 , Joel Pounds 2 Show Abstract
1 Materials Science, Pacific Northwest National Laboratory, Richland, Washington, United States, 2 Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, United States
There is increasing recognition of the importance of understanding the effects of engineered particulate matter on biological toxicity and human health due to exposure during manufacturing processes, use in technological products, and use in biomedical applications for the diagnosis and treatment of diseases. The toxicology of particles in the nanometer size regime is of particular interest since these particles have unique physical and chemical properties and may stimulate different biological responses compared to larger particles. We report studies on the development of system level approaches to determine biomarkers associated with signaling pathways stimulated by different types of nanoparticles. Nanoparticle systems including amorphous silica, crystalline silica, and carbon nanotubes were obtained or synthesized and were characterized for size, phase, surface charge, and surface chemistry. Amorphous silica particles were synthesized in sizes ranging from 10 to 1000 nm. The cytotoxicity and inflammation marker induction in RAW 264.7 macrophage cell lines was studied and found to be dependent on particle size and type. Advanced mass spectrometry (MS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR) techniques were used to identify and quantify extracellular proteins (secretome) released by macrophages in response to nanoparticle exposure. Measurements of the dynamic secretome on a global scale were correlated to genomic microarray data in order to give an understanding of how protein and gene expression patterns change as the chemical constituents and size of particulate matter are systematically varied. Issues involving measurements of dose and the development of techniques to study nanoparticle trafficking will also be discussed.
12:30 PM - FF6.9
Effect of Molecular Structure of Stimuli-responsible Nano-gel Particles for the Oral Peptide Delivery on Interaction between Artificial Mucin Layer in Simulated Intestinal Solutions by using Colloid Probe AFM Method.
Hidehiro Kamiya 1 , Motoyasu Yoshimura 1 , Mayumi Tsukada 1 , Hideki Ichikawa 2 , Yoshinobu Fukumori 2 Show Abstract
1 BASE, Tokyo University of Agriculture and Technology, Tokyo Japan, 2 Faculty of Pharmaceutical Sciences and Cooperative Research Center of Life Sciences, Kobe Gakuin University, Arise 518, Ikawadani-cho, Nishi-ku, Kobe Japan
12:45 PM - FF6.10
Understanding Nanoscale Interfaces to the Proteins Cytochrome c and Ribonuclease S.
Kimberly Hamad-Schifferli 1 Show Abstract
1 Biological and Mechanical Engineering, MIT, Cambridge, Massachusetts, United States
Nanoscale interfaces to proteins have been achieved for a variety of applications, in the form of electrodes to measure conductivity, for sensing on cantilevers or fluorescent quantum dots, or nanoparticles that can be used as reporters in receptor-ligand binding assays. One prevailing requirement is that the biological function of the protein is maintained when linked to nanoscale systems. Due to the structure-function relationship of proteins, the protein must maintain its folded structure. We covalently link cytochrome c and Ribonuclease S to Au or magnetic nanoparticles (NPs) and study the interface, with the goal of constructing design rules that govern the interaction. In both cases we devise methods to achieve linkage of a nanoparticle to the protein on a specific amino acid, in addition to chemical treatments that minimize non-specific adsorption. The protein linked to the nanoparticles is biophysically characterized. Protein secondary structure was quantified by circular dichroism spectroscopy (CD). From these measurements we determine that electrostatic forces dominate the NP-protein interaction and minimization of these results in folded proteins with minimal non-specific adsorption. For Ribonuclease S, these findings are integrated with measurements of enzymatic activity and binding constants KM to yield a picture of the how the protein interaction with the NP affects its binding to the substrate and activity. Experiments in which the NP labeling position, NP ligand, size, and material (Au, Fe3O4, CoFe2O4) are systematically varied will be discussed.
FF7: Nanomaterials in Therapeutic and Regenerative Medicine
Thursday PM, April 12, 2007
Room 2018 (Moscone West)
2:30 PM - **FF7.1
Nanoscale Crafting of Matrices for Regenerative Medicine.
Samuel Stupp 1 2 Show Abstract
1 Materials Science, Chemisty, and Medicine, Northwestern University, Evanston, Illinois, United States, 2 Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, Illinois, United States
Advances in regenerative medicine throughout this century will have great impact on human longevity, quality of life, and the economy. The targets may include, brain repair, heart regeneration, insulin-producing tissue to cure diabetes, the possibility to offer humans new cartilage, bone, and teeth in adulthood, among others. One of the scientific challenges in regeneration is the supramolecular crafting of a three-dimensional artificial matrix to actively control cell function. Ideal biomaterials for the extracellular space need to orchestrate information flow to receptors in highly dynamic fashion. This opportunity in materials innovation will be an exciting one as interactions among signaling pathways are unraveled. The signaling targets could include those linked to cell survival, stem cell differentiation, proliferation, specific cell recruitment, or those involved in the growth of blood vessels on demand to feed cells. Self-assembly is a natural strategy to create the matrix so that bioactive networks can spontaneously grow in the extracellular space. This lecture will describe a supramolecular platform for these artificial matrices using a highly diverse set of molecules that self-assemble into one-dimensional nanostructures. Specific molecular designs for these nanostructures have been found effective in the repair of spinal cord injury to avoid paralysis, the restoration of heart function after infarct, bone growth in non-healing defects, islet survival in diabetes therapies, and wound healing.
3:00 PM - FF7.2
Self-assembled Fmoc-peptide Scaffolds for the 3D Culture of Human Dermal Fibroblasts
Mi Zhou 1 , Rein Ulijn 1 , Julie Gough 1 Show Abstract
1 , The University of Manchester, Manchester United Kingdom
A number of Fmoc (fluorenylmethoxycarbonyl) protected dipeptides can self-assemble into transparent hydrogels at neutral pH and physiological temperatures. These gels possess nano-fibers and over 99% water. The self-assembly is directed by π-π stacking of the aromatic rings in Fmoc, hydrogen bonding and electrostatic interactions among ionic residues. Considering the high resemblance of the self-assembled hydrogel to extracellular matrix, the potential of using these gels for skin tissue engineering was investigated by testing: 1) the diffusion of a range of molecules through these gels; 2) incorporation of cell adhesion peptide sequences (RGD) into the gel structure; 3) ability to support human fibroblast growth in these 3D structures. A permeability test was performed by soaking the self-assembled hydrogels in FITC-labeled dextrans (linear saccharide) and FITC-albumin (globular protein). Dextrans with molecular masses of up to 2,000kDa were able to penetrate into the self-assembled peptide gels suggesting that nutrient molecules (commonly less than 250kDa) could diffuse freely within the gel. Fmoc-GGRGD was combined with Fmoc-FF in various molar ratios (0.1-1) to generate self-assembled gels with RGD motifs, and Fmoc-FF alone, Fmoc-GGRGE mixed with Fmoc-FF were used as comparisons. It was found that mixtures in all molar ratios could self-assemble into gels. Through Fmoc protection groups and ionic amino acids (R, G and E), the two functional peptides (RGD and RGE) effectively incorporated with Fmoc-FF and acted as structural components of the gels. With Fmoc-groups forming the backbone of nanofibres in the gel, it is expected that RGD/E sequences extend outwards and are available for interaction with cultured skin cells. When the RGD/E were in high concentration (i.e. 50:50 of Fmoc-GGRGD/E: Fmoc-FF), the self-assembled gels showed higher strength and elasticity. Human adult dermal fibroblasts were seeded into the Fmoc-FF, Fmoc-FF + Fmoc-GGRGD, and Fmoc-FF + Fmoc-GGRGE gels, and cultured up to 14 days. Cell phenotype was observed and viability was tested using LDH assay. In the 3D culture, round cell phenotype and cell death after an initial 3 days were observed in Fmoc-FF gels, but a steady cell number increase happened between 7-14 days. The reason for regain of proliferation was possibly due to gradual gel degradation which made nutrient diffusion better, and a loss of the false ‘cell-cell contact’ of fibroblasts. By incorporating Fmoc-GGRGD, cells appeared differently with flat and spread membranes; they also possessed larger sizes of average 35 microns compared to 20 microns in Fmoc-FF or Fmoc-GGRGE gels. Cell viability was also improved compared to Fmoc-FF or Fmoc-GGRGE gels, according to MTS assay. These results suggest that Fmoc-peptides can be modified with bioactive peptide epitopes to improve cell behavior.
3:15 PM - FF7.3
Computational Strategies for in-silico Characterization of Nanobioparticles.
Raul Cachau 1 , Martin Fritts 2 , Igor Topol 1 , Stanley Burt 1 , Fernando Gonzalez-Nilo 3 , Mark Matties 4 Show Abstract
1 Advanced Biomedical Computing Center, NCI, SAIC-Frederick, Frederick, Maryland, United States, 2 Nanotechnology Characterization Laboratory, NCI, SAIC-Frederick, Frederock, Maryland, United States, 3 CBSM, Universidad de Talca, Talca Chile, 4 Department of Computer Science, Bowie State University, Bowie, Maryland, United States
3:30 PM - FF7.4
Multivalent Semi-Synthetic Proteins for Biomedical Applications.
Sanne Reulen 1 , Ingrid van Baal 1 , Wilco Brusselaars 1 , Maarten Merkx 1 , E. Meijer 1 Show Abstract
1 Laboratory of Macromolecular and Organic Chemistry and Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven Netherlands
In biology the affinity and specificity of binding are often enhanced by combining multiple ligand-receptor interactions, an effect that is known as multivalency. Multivalency plays a major role in cell-surface interactions, in the immune system (e.g. antibodies are inherently multivalent), and in protein-protein interactions. Synthetic multivalent platforms abound in the literature. Those based on cyclodextrins, dendrimers, polymers and liposomes are common, and typically incorporate carboydrates as recognition elements. These biomaterials have been successfully applied in many applications including drug delivery, targeting and molecular imaging. Multivalent constructs based on peptides and proteins, however, are far less common. These typically require protein engineering to generate controlled supramolecular assemblies of bioactive proteins. To our knowledge, surprisingly few examples of multivalent semi-synthetic proteins have been reported. In order to address this deficiency, we have recently pioneered the use of the native chemical ligation as a robust tool for the functionalization of materials with peptides and proteins. The protocols are general, and in a single step generate multivalent proteins on a wide variety of platforms, including dendrimers, micelles and liposomes. In this manner, we are able to produce dynamic multivalent protein assemblies ranging from 5 - 200 nm in diameter. From our most recent results, we will describe the preparation of a multivalent collagen specific probe based on the collagen binding domain (CNA35) from S. Aureus. These biomaterials show promise in the imaging of ischemic heart diseases. We will also describe the ligation of single-domain antibody fragments to our platforms. By multimerizing the single-domain antibody fragments, the multivalent character of full size monoclonal antibodies is restored, if not improved. Moreover, the antibody is immobilized on the platform in a site-specific manner leading to complete retention of activity and a homogeneous distribution of protein conformers in solution.
3:45 PM - FF7.5
Micro Patterning of Self-Assembling Peptide Amphiphile Nanostructures for the Manipulation of Stem Cells
Alvaro Mata 1 , Shuming Zhang 1 , Lorraine Hsu 1 , Karl Henrikson 1 , Samuel Stupp 1 Show Abstract
1 , Northwestern University, Chicago, Illinois, United States
The combination of microfabrication with molecularly designed self-assembling materials offers the possibility to integrate nano- and micro-meter scale control of biological events. This approach could allow the development of biomimetic environments with multi-dimensional resolution that are designed for optimal biochemical and physical cellular stimuli. In this report, we describe our work concerning the geometrical control of self-assembling peptide amphiphiles (PA) to fabricate nano- and micro-structures for selective stimulation of mesenchymal stem cells (MSCs). PA materials containing specific peptide sequences were designed to self-assemble into well defined nanofibers that form highly hydrated gels. Two PA systems were developed which contained bioactive epitopes such as arginine-glycine-aspartic acid (RGD) for cell adhesion or phosphorylated serine for nucleation of mineral. The first PA system comprised a diacetylene molecule on the alkyl tail that increases intra-fiber cross-linking when exposed to UV irradiation (254 nm) and subsequent gel strength. This system was combined with microfabrication techniques to realize precise microtextures made completely from the self-assembled PA material. The second PA system comprised an amino acid sequence that includes 3 valines, 3 alanines, and 3 glutamic acids (3V3A3E). This system facilitated the alignment of individual of PA nanofibers into larger nanofiber bundles by controlling processing parameters such as temperature conditions and shear stresses. The surfaces were then used as substrates for in vitro culture of MSCs to investigate the effect on cell behavior. Cell growth characteristics were analyzed with immunofluorescent staining, confocal, scanning electron (SEM), and time-lapse microscopy. PA materials comprising the diacetylene molecule self-assembled within the microfabricated molds and formed three-dimensional PA microtextures with either 10 μm high, 20 μm wide channels or 10 μm deep holes ranging between 20 – 40 μm diameters. PA microtextures were rigid enough to provide contact guidance and significantly direct MSC morphology and migration. Cells aligned and migrated along the direction of the PA channels as was evident by the actin cytoskeleton, focal adhesion alignment, and time-lapse microscopy. On the PA hole microtextures cells were confined within the holes and interacted with the 10 μm high vertical walls as was evident by SEM observations and focal adhesion staining. PA materials comprising the amino acid sequence 3V3A3E presented increased nanofiber alignment when pre-heated to 85° C. The individual PA nanofibers formed PA bundles that were ~ 50 nm in diameter and up to ~ 5 μm in length. Confocal and SEM observations revealed that MSCs growing on these bundles exhibited an overall aligned morphology in the direction of the PA bundles. Moreover, cells migrated in the direction of the aligned PA bundles as was evident by time-lapse microscopy.
4:15 PM - **FF7.6
Oligonucleotide-Modified Gold Nanoparticles for Biodiagnostics and Therapeutics
Chad Mirkin 1 Show Abstract
1 Chemistry, Northwestern University, Evanston, Illinois, United States
Oligonucleotide-modified gold nanoparticles (Au NPs) have shown great promise in the area of biodetection and genetic control. DNA-Au NPs are the focal point of the Bio-Barcode Assay, which is capable of detecting attomolar target concentrations (protein or nucleic acid) in a rapid and multiplexed manner. The tremendous detection capability of DNA-Au NPs is currently being expanded to detect metal ions and small molecules. Additionally, DNA-Au NP aggregates have been developed as a colorimetric sensor to screen for duplex and triplex DNA binding molecules. Beyond biological sensing applications, oligonucleotide-modified Au NPs have recently been used as antisense agents for control of protein expression. These antisense particles exhibit a range of unique properties that make them very well-suited for gene regulation. In particular, the particles are highly resistant to nuclease digestion, have high and tailorable binding constants for target mRNA, and exhibit high entry efficiency into multiple cell types.These antisense nanoparticles are a potentially powerful new way of regulating cellular gene expression, and thus hold promise for genetic therapies. By using rationally designed gold nanoparticle complexes as platforms for delivery of oligonucleotides, we have been able to add functionality as well take advantage of the cooperative properties for other methods of gene regulation, and have demonstrated their use in the in vivo control of eGFP expression, thus making oligonucleotide-modified gold nanoparticles attractive candidates for antisense studies and gene therapies.
4:45 PM - **FF7.7
Multivalency at Work.
Brett Helms 1 , Ingrid van Baal 1 , Maarten Merkx 1 , E. Meijer 1 Show Abstract
1 Laboratory of Macromolecular and Organic Chemistry and Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven Netherlands
We will describe our most recent research towards functional materials for targeting and molecular imaging. Particular focus will be given to the design and synthesis of hybrid molecules with interesting biomedical properties. Such hybrids are derived from branched, multivalent platforms – primarily, dendrimers and dendrons. These materials are functionalized with targeting peptides and recombinant proteins using native chemical ligation. Our peptide/protein display approach has been identified as both general and highly robust for the synthesis of biomaterials for many applications in our group. Moreover, the multivalent nature of the ligand-receptor interactions in our systems has been used to enhance the affinity and specificity of the targeting agent. We have since applied this methodology towards more functional systems that offer a broader platform for the further incorporation of imaging groups in addition to the multivalent targeting scheme offered by the display of multiple peptides or proteins at the molecule’s periphery. With this in mind, we will describe a series of dendritic wedges whose termini are functionalized with N-terminal cysteine residues for coupling to C-terminal thioesters (e.g. recombinant proteins or peptides identified from phage libraries) via native chemical ligation. A chemically orthogonal group at the focal point of the dendron has allowed us to further manipulate the material so as to incorporate a wide variety of anchoring and imaging groups. These dendrimer-peptide bioconjugates are attractive targets for studying multivalency in aqueous media, particularly from the perspective of developing tissue specific agents for bioimaging and drug delivery. We will also describe how this methodology is currently being implemented in other constructs for biomedical applications, including tissue engineering and biosensors. The design concepts presented here will be placed in a larger context of how multivalent, dynamic, noncovalent interactions may be harnessed in biomaterials such as ours for more effective molecular medicines in the identification and treatment of disease.
5:15 PM - FF7.8
Magnetic Hyperthermia Study of Mn-Zn-Fe, Co-Gd-Zn and Zn-Gd-Fe Nanoparticle Composits
Saleh Hayek 1 2 , Ching-Jen Chen 1 2 , Glen Flores 3 , Christopher Batich 3 , Yousef Haik 4 Show Abstract
1 Mechanical Engineering, Florida State University, Tallahassee, Florida, United States, 2 FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, United States, 3 Material Science and Engineering, University of Florida, Gainsville, Florida, United States, 4 Department of Mechanical Engineering, United Arab Emirates University, Al Ain United Arab Emirates
Magnetic nanoparticles have found utility in many biological applications, including imaging, cancer therapy, drug delivery, sensing and hyperthermia for tumor therapy. Hyperthermia is raising the tissue temperature between 41.5 - 46 degrees Celcius to kill cancerous cells while preserving the normal cells. Due to the fact that many robust synthetic starategies exist for iron oxides which results in high quality, monodisperse and crystalline nanoparticles, hyperthermia applications have traditionally used magnetic oxide nanoparticles. On the other hand, new materials for hyperthermia that combine the advantages of stability with those of magnetic behavior are desirable. We report the synthesis of MnZnFe, CoGdZn and ZnGdFe nanoparticle composits which are ideal for biological applications over magnetic oxides due to their conjugation chemistry, and surface chemistry. We present an AC magnetic heating studies of these nanoparticle composites which exhibit magnetic field heating. The frequency dependence of the heating follows general trends predicted by power loss equations and is similar to traditional materials.The heating pattern of Zn-Gd-Fe (20mg/ml) using alcohol thermometer at 961 kHz and 433KHz and the heating pattern of Mn-Zn-Fe[Zn = 0.5 conc](20mg/ml) using alcohol thermometer at 961 kH and finally the heating pattern of Co-Gd-Zn [Zn = 0.2 conc Gd(1-X)](20mg/ml) using alcohol thermometer at 961 kHz are reported. X-Ray Diffraction studies and SQUID magnetic measurments and TEM and EDX particle size and constituents measurments are also included for all three nanoparticle compsites. In conclusion, high quality heating nanoparticle composits were developed for hyperthermia treatment of cancer. The composites generate sufficient heat at room temperature and stops heating at the Curie temperature Tc of the respective nanoparticle composit.
5:30 PM - FF7.9
Functionalization and Effect of Hydroxyl Groups on the Stability of Oxidation State in Ceria Nanoparticles.
Ajay Karakoti 1 , Satyanarayana Kuchibhatla 1 2 , Sameer Deshpande 1 , Sureshbabu Krishnamoothy 1 , Sudipta Seal 1 3 Show Abstract
1 Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, Florida, United States, 2 , Environmental Molecular Sciences Laboratory,Pacific Northwest National Laboratory, Richland, Washington, United States, 3 Nanosciece and Technology Center, University of Central Florida, Orlando, Florida, United States
Cerium oxide (ceria) can be considered as one of the most important rare earth oxides. In conjunction with the benefits of nanotechnology, it has found enormous applications in catalysis, sensors and biomedical applications. These applications stem from its ability to switch oxidation states between +3 and +4 depending on ambient conditions. Nanoceria has been shown to impart protection to cells against the reactive oxygen species (ROS) by our group. We have also established a preferential protection of the normal cells against radiation damage as compared to the tumor cells. These stimulating properties of nanoceria make it imperative to stabilize it in various aqueous and non-aqueous solvents for practical applications. Systematic engineering of nanoceria in media like poly (ethylene glycol) (PEG), dextran and glucose can be of great importance in biological applications. Dextran and PEG have been used extensively to stabilize nanoparticles in solution. Biocompatibility of these media can be exploited to disperse nanoceria inside the body to provide cell protection. Unlike most of the reported work, where a two step synthesis and re-dispersion strategy is used, nanoceria prepared under room temperature wet chemical synthesis shows active switching of oxidation states. In the present work we report the successful synthesis of nanoceria in glucose, dextran and their effect on stability of nanoparticles in acidic and basic media. The role of polyhydroxyl group in complexing ceria and their subsequent oxidation/hydrolysis is monitored using UV-VIS spectroscopy. The nanoparticle characterization using high resolution transmission electron microscopy (HRTEM) for structure and morphology and X-ray Photoelectron Spectroscopy (XPS) for oxidation states will be reported. An effort will be made to present the quantitative analysis of various results.
5:45 PM - FF7.10
Engineered Nanoparticulate Sysyems For Biomedical Applications.
Brij Moudgil 1 , Parvesh Sharma 1 2 , Scott Brown 1 , Swadeshmukul Santra 4 , Glenn Walter 3 , Edward Scott 5 Show Abstract
1 Department of Materials Science & Engineering and Particle Engineering Research Center, University of Florida, Gainesville, Florida, United States, 2 Department of Chemistry, St. Stephen's College, Delhi, Delhi, India, 4 Department of Chemistry and Burnett College of Biomedical Sciences, University of Central Florida, Orlando, Florida, United States, 3 Department of Physiology and Functional Genomics and McKnight Brain Institute, University of Florida, Gainesville, Florida, United States, 5 Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States
Engineered nanoparticulate systems are anticipated to lead to advances in understanding biological processes at the molecular level and progress in the development of diagnostic tools and innovative therapies. Nanoparticle based imaging agents such as fluorescent dye-doped silica nanoparticles, quantum dots, gold nanoparticles, etc. have overcome many of the limitations of conventional contrast agents (organic dyes) such as poor photostability, low quantum yield and insufficient in vitro and in vivo stability. Additionally, the development of multifunctional nanoparticles, which can be detected simultaneously by multiple techniques e.g. Magnetic Resonance Imaging (MRI) and Optical Imaging integrate the advantages of high sensitivity (from optical method of detection, e.g., fluorescence) with the potential of true three dimensional imaging of biological structures and processes at cellular resolution (e.g. via MRI). Microemulsions have attracted considerable interest as potential delivery vehicles for drugs with poor aqueous solubility as well as for drug detoxification. Several favorable properties of microemulsions such as transparency, easy of preparation, sterilization and nanometer droplets size (providing a relatively high interfacial area and low interfacial energy) have made them suitable for drug detoxification applications. In this presentation, highlights of advances made in synthesis, characterization and performance evaluation of nanoengineered particulate systems in targeted areas such as imaging of biological specimens using photostable nanoparticle based imaging probes, pulmonary therapeutics, and microemulsion mediated detoxification of drugs will be discussed. The toxicological assessment of selected systems will also be presented.