Thin films and assemblies of photosensitive membrane proteins and colloidal nanocrystals for engineering of hybrid materials with advanced properties

• Published in: Advances in colloid and interface science Vol. 183-184; pp. 14 - 29
• Main Authors: Zaitsev, Sergei Yu, Solovyeva, Daria O., Nabiev, Igor
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2012; Elsevier
• Subjects: Bacteria; Bacteriorhodopsin; Bacteriorhodopsins - chemistry; Bioengineering; Biotechnology; Colloidal nanocrystals; Colloids; Devices; Electronics; Energy Transfer; Engineering Sciences; Halobacterium salinarum - chemistry; Langmuir films; Layer-by-layer; Life Sciences; Light; Membranes; Membranes, Artificial; Micro and nanotechnologies; Microelectronics; Nanoparticles - chemistry; Nanostructure; Nanotechnology; Nano–bio hybrid materials; Photosynthesis; Photosynthetic reaction centres; Polymers - chemistry; Proteins; Purple Membrane - chemistry; Purple membranes; Self-assembly; Semiconductors; Thin films; Bacteriorhodopsin; Self-assembly; Purple membranes; Photosynthetic reaction centres; Langmuir films; Colloidal nanocrystals; Nano–bio hybrid materials; Layer-by-layer
• ISSN: 0001-8686; 1873-3727
• DOI: 10.1016/j.cis.2012.07.003

The development and study of nano–bio hybrid materials engineered from membrane proteins (the key functional elements of various biomembranes) and nanoheterostructures (inorganic colloidal nanoparticles, transparent electrodes, and films) is a rapidly growing field at the interface of materials and life sciences. The mainspring of the development of bioinspired materials and devices is the fact that biological evolution has solved many problems similar to those that humans are attempting to solve in the field of light-harvesting and energy-transferring inorganic compounds. Along this way, bioelectronics and biophotonics have shown considerable promise. A number of proteins have been explored in terms of bioelectronic device applications, but bacteriorhodopsin (bR, a photosensitive membrane protein from purple membranes of the bacterium Halobacterium salinarum) and bacterial photosynthetic reaction centres have received the most attention. The energy harvesting in plants has a maximum efficiency of 5%, whereas bR, in the absence of a specific light-harvesting system, allows bacteria to utilize only 0.1–0.5% of the solar light. Recent nano-bioengineering approaches employing colloidal semiconductor and metal nanoparticles conjugated with biosystems permit the enhancement of the light-harvesting capacity of photosensitive proteins, thus providing a strong impetus to protein-based device optimisation. Fabrication of ultrathin and highly oriented films from biological membranes and photosensitive proteins is the key task for prospective bioelectronic and biophotonic applications. In this review, the main advances in techniques of preparation of such films are analyzed. Comparison of the techniques for obtaining thin films leads to the conclusion that the homogeneity and orientation of biomembrane fragments or proteins in these films depend on the method of their fabrication and increase in the following order: electrophoretic sedimentation < Langmuir–Blodgett and Langmuir–Schaefer methods < self-assembly and layer-by-layer methods. The key advances in the techniques of preparation of the assemblies or complexes of colloidal nanocrystals with bR, purple membranes, or photosynthetic reaction centres are also reviewed. Approaches to the fabrication of the prototype photosensitive nano–bio hybrid materials with advanced photovoltaic, energy transfer, and optical switching properties and future prospects in this field are analyzed in the concluding part of the review. [Display omitted] ► Making assemblies and ordered films is a key step in designing nano–bio hybrid devices. ► Approaches to designing films and assemblies of photosensitive proteins are reviewed. ► Self-assembly and layer-by-layer methods provide highly ordered and homogeneous films. ► Colloid nanocrystals enhance light harvesting and photovoltaic biological functions. ► Nano–bio complexes with enhanced biological function are reviewed.