Adsorption behavior and photoelectric response characteristics of bacteriorhodopsin thin films fabricated by self-assembly technique

초록

The characteristics of bacteriorhodopsin (bR)-based thin films fabricated by self-assembly (SA) technique were investigated. Self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (11-MUA) were spontaneously formed onto a pretreated gold substrate by soaking it into the ethanolic solution of 11-MUA, and used as a template for the adsorption of bR. Using poly-L-lysine as a bridging molecule for bR adsorption onto SAMs of 11-MUA, bR-embedded purple membrane fragments were adsorbed by electrostatic attractive force. By ellipsometry and atomic force microscopy, the properties of the prepared bR-based thin films were investigated with the various fabrication conditions, such as bR suspension concentration and pH. An artificial photoreceptor was then fabricated with a sandwich-type structure of ITO/electrolyte gel/bR-based thin films/gold substrate. According to the monochromatic light illumination (560 nm) using Xenon lamp system, photoelectric responses of the fabricated photoreceptor were detected and analyzed. The stability of photoreceptors composed of the bR films fabricated by different technique was also examined over the period of 60 days. It is concluded that the SA technique could be usefully applied to the protein-based thin films preparation for the development of bioelectronic devices. (C) 2002 Elsevier Science B.V. All rights reserved.

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