Andreas Offenhäusser, Forschungszentrum Juelich
Roisin Owens, University of Cambridge
Sahika Inal, King Abdullah University of Science and Technology
Christian B. Nielsen, Queen Mary University of London
BM07.01: Flexible, Stretchable Active/Passive Materials/Devices for Health Monitoring
Christian B. Nielsen
Monday AM, November 26, 2018
Sheraton, 2nd Floor, Constitution B
8:00 AM - BM07.01.01
Bioinspired Wet/Dry Adhesion for Bioelectronics
Changhyun PangShow Abstract
Recently, extraordinary performances of natural creatures living in various conditions have been explored to understand their reversible dry/wet adhesion, including gecko feet, insect secretion, mosquito needles or endoparasitic worm’s proboscis, octopus suction cups, and slug’s footpad with viscous mucus. Extensive studies on the adhesive properties of such animal skins have revealed various multiscale architectures inducing various physical interactions. The attachment phenomena of various hierarchical architectures found in nature have extensively drawn attention for developing highly biocompatible adhesive on skin or wet inner organs without any chemical glue. Structural adhesive systems have become important to address the issues of human-machine interactions by smart outer/inner organ-attachable devices for diagnosis and therapy.
Breakthroughs in flexible and conductive materials have accentuated the development of wearable or organ-attachable bioelectronics for stable biosignal monitoring and drug delivery. For such medical applications, the devices need to manifest conformal contact on human skin even under dynamic movements, as well as repeatable, long-term attachment without skin irritations or chemical contaminations. Here, we investigated an artificial reversible wet/dry adhesion systems biologically inspired by the suction cups of octopi and amphibian’s pad. Our biologically inspired architectures exhibit strong, reversible, highly repeatable adhesion to silicon wafers, glass, and rough skin surfaces under various conditions. Applying these bioinspired architectures to interfacial adhesive layers can attribute to developing skin-attachable or implantable bioelectronics for health diagnosis, controlled drug therapeutics, and achieving multifunctional integrated devices for ubiquitous-healthcare systems.
8:15 AM - BM07.01.02
Nanocellulose Printed Circuit Boards for Human Monitoring
Jonathan Yuen1,Dan Zabetakis1,Lisa Shriver-Lake1,Md Qumrul Hasan2,David Stenger1,Scott Walper1,Gymama Slaughter2
Naval Research Laboratory1,University of Maryland, Baltimore County2Show Abstract
Flexible and ultrathin substrates supporting microelectronic components have the potential to spur the development of pervasive healthcare and the internet of things by providing sensors and bioelectronics that can provide seamless and imperceptible integration. We will describe our ongoing work to develop sensing electronics on microns-thin bacterial nanocellulose for human monitoring applications. The porosity and hydrophobicity of nanocellulose sheets offer advantages that typical plastics cannot provide, such wicking of analytes and absorption of inks. We have developed a printing method to form nanocellulose printed circuit boards (PCBs), and created a simple low temperature soldering process to form circuit structures using standard surface-mount components on our nanocellulose PCBs. This has been used to create nanocellulose decals that measure human body temperature and perform pulse oximetry. We have also developed self-powered electronics for sensing of bioanalytes, such as glucose. For all applications, the fabrication processes are solution-based and requires only ambient processing, and therefore simple, potentially low-cost, and can be aimed for a wide range of applications.
8:30 AM - BM07.01.03
Intrinsically Stretchable Polymer Semiconductors and Electronics as an Emerging Platform for Bioelectronics
The University of Chicago1Show Abstract
The vast amount of biological mysteries and biomedical challenges faced by human provide a prominent drive for seamlessly merging electronics with biological living systems (e.g. human bodies) to achieve long-term stable functions. Towards this trend, the main bottlenecks are the huge mechanical mismatch between the current form of rigid electronics and the soft biological tissues.
In this talk, I will first describe a new form of electronics with skin-like softness and stretchability, which is built upon a new class of intrinsically stretchable polymer materials and a new set of fabrication technology. As the core material basis, intrinsically stretchable polymer semiconductors have been developed through the physical engineering of polymer chain dynamics and crystallization based on the nanoconfinement effect. This fundamentally-new and universally-applicable methodology enables conjugated polymers to possess both high electrical-performance and extraordinary stretchability. Then, proceeding towards building electronics with this new class of polymer materials, the first polymer-applicable fabrication platform has been designed for large-scale intrinsically stretchable transistor arrays. As a whole, these renovations in the material basis and technology foundation have led to the realization of circuit-level functionalities for the processing of biological signals, with unprecedented mechanical deformability and skin conformability. Equipping electronics with human-compatible form-factors has opened a new paradigm for wearable and implantable bio-electronic tools for biological studies, personal healthcare, medical diagnosis and therapeutics.
 J. Xu#, S. Wang# …… Z. Bao Science 355, 59-64 (2017).
 S. Wang#, J. Xu# …… Z. Bao Nature 555, 83-88 (2018).
 S. Wang#, J. Y. Oh#, J. Xu#, H. Tran, Z. Bao Accounts of Chemical Research 51, 1033–1045 (2018).
8:45 AM - BM07.01.04
Human Inspired Bio-Electronic Sensor Skins
Benjamin TeeShow Abstract
Human sensory organs such as the skin have evolved to have excellent sensing performance and ultra-robustness. Electronic versions of skin have witnessed tremendous interest and development over the last decade1. Functional soft, flexible and stretchable materials are crucial to the continued evolution of skin-like sensor applications in emerging robotic systems2, new human-machine interfaces and life-like prosthetics3.
Here, I will discuss our recent work in next generation technologies for bio-electronic skins using an integrated hybrid materials approach that synergizes the best qualities of organic and inorganic materials. For example, recent developments in self-healing polymeric systems have propelled the exciting notion that electronic systems can repair themselves when damaged4. Bio-inspired digitization of analog signals have also enabled us to develop artificial mechano-receptors that optically interfaces with neurons5. These sensor and materials technologies would be extremely applicable in an increasingly advanced cybernetic and Artificial Intelligence (AI) robotics future.
1. Hammock, M. L., Chortos, A., Tee, B. C. K., Tok, J. B. H. & Bao, Z. 25th anniversary article: The evolution of electronic skin (E-Skin): A brief history, design considerations, and recent progress. Adv. Mater. 25, 5997–6038 (2013).
2. Larson, C. et al. Highly stretchable electroluminescent skin for optical signaling and tactile sensing. Science 351, 1071–4 (2016).
3. Lipomi, D. J. et al. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. Adv. Mater. 23, 1771–1775 (2012).
4. Tan, Y. J., Wu, J., Li, H. & Tee, B. C. K. Self-Healing Electronic Materials for a Smart and Sustainable Future. ACS Appl. Mater. Interfaces 10, 15331–15345 (2018).
5. Tee, B. C. K. et al. A skin-inspired organic digital mechanoreceptor. Science (80-. ). 350, 313–316 (2015).
9:15 AM - BM07.01.05
Fully Printed All-Polymer Tattoo/Textile Electronics for Electromyography
Eloise Bihar1,Timothee Roberts2,Jozina De Graaf2,Mohamed Saadaoui3,Esma Ismailova3,George Malliaras4,Khaled Salama1,Sahika Inal1
King Abdullah University of Science and Technology1, Aix Marseille Universite2,Ecole des Mines de Saint Etienne3,University of Cambridge4Show Abstract
Driven by the ever-growing needs for developing portable, easy-to-use, noninvasive diagnostic tools, biomedical sensors that can be integrated on textiles or even directly on human skin have come to fruition. Wearable sensor technologies that seamlessly interface electronics with human skin can be especially promising for detecting a wealth of biologically relevant signals ranging from neuro-muscular activity, to electrophysiology, even to metabolite profiles.
In this work, we present a simple and low cost platform fabricated on a tattoo paper used for on-skin electromyography (EMG) measurements. The electrodes comprising the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) are directly inkjet-printed on the tattoo paper. Addressing the integration challenge common for stretchable electronic devices, we connect the tattoo electrodes to the acquisition system through a textile in the form of a wristband comprising of printed PEDOT:PSS contacts. While the textile wristband conforms around the “tattooed” skin, it enables a reliable contact with the electrodes beneath due to its conformability around the limb. We show that this tattoo/textile electronics system, which does not rely on gels or expensive metallic materials, is able to detect the biceps activity of the arm during muscle contraction for a period of seven hours, with comparable performance to conventional wet biopotential electrodes. Combining the tattoo electronics with the electronic textile allows for facile integration of skin-like electrodes with external electronics.
9:30 AM - BM07.01.06
Fabrication of Fabric Biomedical Electrode Array with Printable Electronic Ink and Hot-Melt Film for Electromyography
Seiichi Takamatsu1,Toshihiro Itoh1
The University of Tokyo1Show Abstract
We have developed fabric biomedical electrode array where silver paste, conductive polymer and ionic liquid gel are printed and insulation layers are formed with hot melt film on the fabric substrate.
Recently, wearable electronic devices such as Microsoft Hololens, google glass, sportsband, or other tools have been developed and commercialized for human healthcare monitoring and information tools. Among wearable electronic devices, wearable ECG or EMG electrodes are promising for human motion sensing tools. Especially for monitoring human hand or foot motion sensing, the biomedical electrode array which is made of fabric is necessary.
To make biomedical electrodes array, new fabrication process of fabric multilayer electrodes which consists of biomedical electrode parts to contact human skin and the wiring parts from biomedical electrodes parts to the amplifiers are required. Previous study (S. Takamatsu,et.al., "Direct patterning of organic conductors on knitted textiles for long-term electrocardiography," Scientific Reports, vol. 5, 15003(7pp), Oct 2015.) reports single layer fabric electrodes, but the multilayer electrodes has not been fabricated on the fabric and the biomedical electrode array has not been achieved. The most difficult fabrication process to make multilayer electrodes is to construct insulation layer between multiple electrode because most of the insulation inks are dissolved by the solvent of second layer electrode ink(i.e., toluene), or dissolve the first layer electrode with the solvent of the insulation ink. Our new fabrication process of fabric multilayers consists of the electronic ink printing and hot-melt film sticking on the fabric. Laser cut hot melt film is placed on the electrode printed film and heated to stick to the film as insulation layer. Hot melt film has the advantages in which the hot melt film is not dissolved in the solvent of inks and can combine several layers of functional fabric and films.
The developed fabrication process of fabric biomedical electrode array with printable electronic ink and hot-melt film for Electromyography is following steps. 1. Silver paste wiring electrode is printed on the stretchable polyurethane film. 2. Laser cut hot melt film is placed on the electrode and heated. 3. The patterned urethane film is attached on the knit fabric with hot melt film. 4. Conductive polymer of PEDOT PSS and ionic liquid gel is patterned on another knit fabric for making biomedical electrode part. 5. Wiring part fabric and biomedical electrode fabric are attached by hot melt film and glue. By using our process, the 2x5 array biomedical electrode which has 1cm2 biomedical electrodes parts and 0.5 mm wide wiring can be successfully fabricated. The impedance between electrodes and human skin is less than 1 MOhm, which is useful for EMG monitoring. Thus, our process will useful for wearable multi array of EMG measurement.
9:45 AM - BM07.01.07
Sub-300 nm Thin-Film Au/Parylene Dry Electrodes for Motion Artifact-Less sEMG and sECG Monitoring
Robert Nawrocki1,2,3,Hanbit Jin1,Sunghoon Lee1,Tomoyuki Yokota1,Masaki Sekino1,Takao Someya1,4
Univ of Tokyo1,Purdue University2,Birck Nanotechnology Center3,Thin-Film Device Laboratory & Center for Emergent Matter Science (CEMS)4Show Abstract
Accurate, imperceptible and long-term monitoring of vital biopotential signals promises to revolutionize healthcare industry by shifting from costly and uncomfortable hospital visits to in-home usage. Currently available wearable electronics are typically rigid with non-conformal skin contact resulting in poor data quality, necessitating the integration of such bioelectronics  directly onto the skin . Increasing the conformity of the artificial electronic skin to the soft, irregular and stretchable human skin typically results in improved signal quality and user comfort .
We report on the fabrication of self-adhesive and conformable to highly irregular three-dimensional soft surfaces, sub-300 nm thin dry electrodes that produce biopotential (sEMG and sECG) recordings of excellent quality (SNR). The electrodes are based on thermally evaporated thin film (100 nm) of Au, sandwiched between two layers (100 nm each) of CVD-deposited biocompatible parylene (parylene/Au/parylene). They are fabricated on glass substrates, with fluorinated polymer (85 nm) and poly(vinyl alcohol) (PVA, 5 µm) sacrificial layers used for delamination and ease of handling. Parylene is etched away at the skin-interface side, allowing for direct Au contact with the skin. Following delamination, electrodes are placed on pre-stretched human skin and sprayed with H2O to remove PVA, forming a skin/Au/parylene structure. The skin is then dried and relaxed, with the ultra-thin film conforming to the skin groves via wan der Waals forces , without any additional adhesives.
These simple-to-fabricate and use, ultra-thin sensors show single-day electrical and mechanical stability of up to ten hours. Their bending stiffness was calculated to be comparable to stratum corneum, the uppermost layer of human skin, at ~0.33 pNm2, which is over two orders of magnitude lower than the bending stiffness of a 3.0 µm thin sensor. Compared with the thicker sensor, its impedance also decreased by almost two orders of magnitude. Laminated on a pre-stretched elastomer, the sensor forms wrinkles with a period of 17 µm and amplitude of 4 µm, agreeing with theoretical calculations.
In contrast to wet adhesive Ag/AgCl electrode, with skin vibrations of up to ~15 µm, the sensor demonstrates motion artifact-less sEMG monitoring. Additional impedance and sEMG measurements reveal that the decrease of impedance, as well as the motion artifact-less operation, is likely due to improved skin adhesion of the sub-300 nm thin sensor.
With compatible fabrication to our previously demonstrated sub-300 nm thin electronics , this demonstrates a path for integration of skin-laminated systems consisting of sensors and electronics.
 M. Irimia-Vladu, et al., Adv. Fun. Mat. 20, 4069-4076 (2010)
 T. Yokota, et al., Science Adv. 2, e1501856 (2016)
 D.H Kim, et al., Nature Mat. 9, 511-517 (2010)
 M. Fernandez, et al., Biomed Inst. Tech. 34, 125 (2000)
 R. Nawrocki, et al., Adv. Ele. Mat. 2, 4 (2016)
10:30 AM - BM07.01.08
Multifunctional Silk Adhesive for Epidermal Electronics
Ji-Won Seo1,Hyojung Kim1,Hyunjoo Lee1
Korea Advanced Institute of Science and Technology1Show Abstract
In order to improve the signal accuracy and long-term monitoring of electronics on biological skin, it is essential to achieve a conformal and robustly adhered electronics/biological skin interface. Here, we suggest a biocompatible calcium (Ca)-modified silk adhesive for robust epidermal electronics on biological skin. At optimized weight ratio of silk:Ca2+ of 70:30, the silk adhesive shows strong adhesion force (> 600 N/m) through enhanced mechanical interlocking at interface. The physical mechanism facilitates a high adhesion on various substrates and a reusability of silk adhesive. Moreover, a water-degradability of silk adhesive shows the easy detachment without any high external force. With the multifunctional characteristics such as reusability, biocompatibility, and water-degradability, we fabricate the practical epidermal electronics: strain sensor, touch sensor, and long-term drug delivery system to demonstrate the potential of the proposed silk adhesive.
10:45 AM - BM07.01.09
Deformable Electronic Materials for Two-Way Communication with Biological Systems
University of California, San Diego1Show Abstract
The goal of this project is to create a class of electronic materials that can measure signals and interface with the nervous system for two-way communication with biological systems. The project is exploring two classes of materials. (1) Metallic nanoislands on single-layer graphene for cellular electrophysiology and wearable sensors. We have used these materials to measure the forces produced by the contractions of cardiomyocytes using a piezoresistive mechanism. Separately, we have developed orthogonal methods of stimulating myoblast cells electrically while measuring the contractions optically (a modality we nicknamed as “piezoplasmonic”). We have also used these sensors to measure the swallowing activity of head-and-neck cancer patients who have received radiation therapy and are at risk of dysphagia arising from fibrosis of the swallowing muscles. The combination of strain sensing, surface electromyography, and machine learning can be used to measure the degree of dysphagia. (2) We have developed ionically conductive organogels for haptic feedback. Medical haptic technology has myriad potential applications, from robotic surgery and surgical training, to tactile therapy for premature infants and patients with neurological impairment.
11:00 AM - BM07.01.10
Ultrasoft, Bio-Compatible Electronic Systems for NeuroScience
Osaka University1Show Abstract
We present an implantable sheet-type flexible electronic sensor system for long-term simultaneous monitoring of an electrocorticogram (ECoG) from the brain surface and local field potential (LFP) from the deep brain. Ultrasoft gel electrodes provide a minimally invasive interface consisting of highly conductive nano-conductive materials including Ag-based nanowires, thermoplastic polymers, and bio-compatible gels. The gel composite shows conductivity greater than 10,000 S/cm and can be stretched more than 100% without any reduction to its electrical and mechanical performance. Hence, it can be stretched across arbitrarily curved surfaces, including the ultrasoft brain surface.
By integrating ultrafsoft gel electrodes, an ultraflexible amplifier, and a wireless Si-LSI platform with a thin-film battery, we intend to demonstrate the applications of long-term implantable wireless sheet sensors, including 64-channel sheet-type electric potential monitoring systems. This wireless system with soft gel electrodes can measure biological signals of less than 1 μV. Taking full advantage of this system, simultaneous signals from the cerebral cortex in the ECoG and LFP have been wirelessly measured in animal experiments including non-human primates for over a month. Long-term biocompatibility, electrical performance, and mechanical stretchability and durability are discussed for the integration of nanomaterials and processes and wireless low-noise sheet-type systems.
This research is partially supported by the Brain Mapping by Integrated Neurotechnologies for Disease Studies (Brain/MINDS) from Japan Agency for Medical Research and development, AMED.
11:30 AM - BM07.01.11
Flexible Biosensors for Non-Invasive Medical Diagnostics
Agostino Romeo1,Paul Eduardo David Soto Rodriguez1,Ana Moya2,3,Gemma Gabriel2,3,Rosa Villa2,3,Rafael Artuch4,5,Samuel Sanchez1,6
Institute of Bioengineering of Catalonia1,National Centre of Microelectronics - Microelectronics Institute of Barcelona2,Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN)3,Hospital Sant Joan de Déu4,CIBER-ER (Biomedical Network Research Center for Rare Diseases), Instituto de Salud Carlos III5,Institucio Catalana de Recerca i Estudis Avancats (ICREA)6Show Abstract
In the last few decades the quality of life has significantly improved due to the achievements of biomedical technology. Innovative healthcare solutions contributed to these advances by decreasing costs and making health assessment easier and more accessible. Versatile biochemical sensors targeted to health biomarkers and bioanalytes (metal ions, proteins, amino acids, glucose, lactate, etc.) can non-invasively monitor the health status of the user by analyzing external body fluids (sweat, saliva, tear fluid) alternative to blood.[1,2] On-demand biosensing is envisaged due to the versatility of sensing platforms that can adapt to specific needs in terms of target biomarkers and health issues to monitor. To this regard, several recognition systems, including antibodies, enzymes, and inorganic nanomaterials can be used to modify the sensors to achieve high selectivity towards target analytes. In this scenario, recent advances in microfabrication, sensor technologies and data transmission led to the developments of point-of-care (PoC) diagnostics.
Here we present few examples of bios