Nanostructured interfaces between photosynthetic bacterial Reaction Center and Silicon electrodes

Optimizing interfaces between photosynthetic natural photoconverters, like photosynthetic
bacterial Reaction Centers (RCs) and electrode surfaces represents a challenge in the
progress of bio-optoelectronic devices. The features of the surfaces may result detrimental for
the tertiary and quaternary structures of the RC, even resulting in the denaturation of the
enzyme. Functional surfaces possessing both confinement capability and conductive features
able to preserve the conformation of the biomolecule and its bioelectronic behaviours are
highly needed. In this work, the RC is adsorbed on diatomaceous silica and plasma treated
hydrophobic silicon based materials. Both the materials are demonstrated to be able to preserve and enhance the RC photoconverting activity. In particular, we evaluate the
functioning of isolated bacterial RC interacting with flat pSi electrode through two
nanotextured interfaces designed to address the RC: a thin conductive silicon film
nanotextured in pillars via plasma treatment, and a cast film of nanostructured dielectric
biosilica obtained from diatomaceous earth. The characterization of these interfaces, together
with the RC photocurrent production measurements, pave the way to new generation RC
based bio-devices for photocurrent investigation.