11:00 AM - SB05.01.08
The Photosynthetic Reaction Center Encapsulated in Micro and Nano Containers Based Upon Melalin-like Polymers
Massimo Trotta1,Danilo Vona2,Gabriella Buscemi2,1,Stefania Cicco1,Roberta Ragni2,Angela Agostiano2,1,Francesco Milano1,Marco Lo Presti2,Gianluca Farinola2
Consiglio Nazionale delle Ricerche1,Università degli Studi di Bari Aldo Moro2
The photosynthetic enzyme reaction center (RC) is the photochemical core of the photosynthetic bacterium Rhodobacter sphaeroides, a bacterium able to grow using light as sole energy source. The RC is a transmembrane protein composed by three subunits and nine cofactors involved in a cascade of electron transfer reactions that, upon the absorption of a photon, produce a hole-electron couple. The electrical charges generated within the enzyme are roughly 3 nanometers apart from each other and have a lifetime that can last from tenths to few seconds. The generation of such nanocapacitor has a conversion photons to electrons efficiency close to unity, making this biological trabsduction appealing in principle for bioelectronics applications.  This biological macromolecule are also amenable for the assembly of organic-biological hybrids with improved enzymatic photoconvertion ability. [2-4]
Such photoconverters, either bare or as biohybrids, require an optimised interface with electrode surfaces for their applications . Recently polydopamine (PDA), a self-assembling melanin-like bioinspired polymer, has been exploited to attach and protect enzyme into metal-organic frameworks (MOF)  and graphene nanosheets  on devices substantially maintaining their activities.
We present here PDA nanoparticles containing the photosynthetic RC able to confine the photoenzyme that retains unaltered the photoactivity, i.e. the capability to generate nanocondensers. The RC has been encased into PDA particles of different size from the micrometer to the nanometer, the smaller being characterised by a bright yellow luminescence. These PDA nanocontainers have an intrinsic n type semiconductive  making these organic RC containing nanocapsules highly interesting for bioelectronics purpose.
This work was funded by European Commission through the EU project 800926 - HyPhOE (Hybrid Electronics based on Photosynthetic Organisms)
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