posted on 2015-05-13, 00:00authored byEvan A. Gizzie, Gabriel LeBlanc, G. Kane Jennings, David E. Cliffel
In this work, we report for the first
time the entrapment of the biomolecular supercomplex Photosystem I
(PSI) within a conductive polymer network of polyaniline via electrochemical
copolymerization. Composite polymer–protein films were prepared
on gold electrodes through potentiostatic electropolymerization from
a single aqueous solution containing both aniline and PSI. This study
demonstrates the controllable integration of large membrane proteins
into rapidly prepared composite films, the entrapment of such proteins
was observed through photoelectrochemical analysis. PSI’s unique
function as a highly efficient biomolecular photodiode generated a
significant enhancement in photocurrent generation for the PSI-loaded
polyaniline films, compared to pristine polyaniline films, and dropcast
PSI films. A comprehensive study was then performed to separately
evaluate film thickness and PSI concentration in the initial polymerization
solution and their effects on the net photocurrent of this novel material.
The best performing composite films were prepared with 0.1 μM
PSI in the polymerization solution and deposited to a film thickness
of 185 nm, resulting in an average photocurrent density of 5.7 μA
cm–2 with an efficiency of 0.005%. This photocurrent
output represents an enhancement greater than 2-fold over bare polyaniline
films and 200-fold over a traditional PSI multilayer film of comparable
thickness.