Monolithically integrated bacteriorhodopsin/semiconductor opto-electronic integrated circuit for a bio-photoreceiver

Photoelectric properties of a detector based on dried bacteriorhodopsin film

“…Due to the large number of variables involved in the process, a mathematical model is more efficient to illustrate the interaction between the variables and the behaviour of bR films. A number of models have been developed to explore the photoelectric properties of bR thin films (Hong, 1999;Der and Keszthelyi, 2001;Huang et al, 2003;Xu et al, 2004;Yao et al, 2003). Most of the models arising from these studies were based on the behaviour of wet bR films, where the kinetics exhibits similar attributes to the wild-type bR in liquid suspension.…”

Enhanced Photocurrent in Engineered Bacteriorhodopsin Monolayer

“…4 The retinal isomerization occurs within a few picoseconds of the photocycle initiation and changes the position of the Schiff base by ∼0.4 Å. 11,12 Even though this charge redistribution induces both an internal photovoltage within ns of illumination 13 and a significant change in the spectral properties of BR (λ max changes from 568 to 412 nm), 14 it results in a relatively minor conformational change (concentrated mainly in the orientation of helices F and G). 15 Here, the M163C mutation on the E-F loop of BR has been designed to exploit this sensitivity, that is to bring the most responsive part of the protein into close proximity to the underlying surface.…”

“…17,18 These characteristics have driven a considerable interest in the incorporation of BR into electronic circuitry; suggested applications have included an artificial retina, photochromic data storage, holographic cameras, and information processing. 13,14,19,20 A diverse range of methods for immobilization of BR have been explored and documented. These have included drop drying, which results in nonorientated multilayers; 21 LangmuirÀ Blodgett approaches, in which films are initially compressed at an airÀwater interface; 22 the use of electrophoretic sedimentation (wherein external electric fields act on the purple membrane ABSTRACT: The integration of the transmembrane protein bacteriorhodopsin (BR) with man-made electrode surfaces has attracted a great deal of interest for some two decades or more and holds significant promise from the perspective of derived photoresponse or energy capture interfaces.…”

Directed evolution of bacteriorhodopsin for applications in bioelectronics

“…The native protein contains no cysteine residues and thus the strategic addition of cysteine residues in the loop regions of BR via site-directed mutagenesis allows BR to rsif.royalsocietypublishing.org J R Soc Interface 10: 20130197 covalently bind to gold. Enhancing the dipole moment of BR is critical for the application of the protein in photovoltaic devices [23,89,115]. Altering the intrinsic dipole moment through charge substitution in the helical loop regions of the protein allows the protein to pack more densely, while enhancing the photovoltaic output or signal from BR.…”