NanoPhotoChrome - Energy conversion within the hybrid materials engineered from the nanocrystals quantum dots and photochromic membrane proteins

Most photosensitive integral membrane proteins (PIMP) are not able to deal with the excess energy of photons from UV to blue region and normally do not absorb them at all. If high-energy photons were absorbed, they might destroy the light-harvesting chromophores or even induce apoptotic-like cell death. Thus, the energy efficiency of green plants is less than 5% and the energy-producing PIMP bacteriorhodopsin (bR) not possessing specific light-harvesting system utilizes less than 0.5% of solar light. Nanotechnology opens the way to increase performances of biological functions. Summarizing the sources of energy losses provides an idea to optimization through the engineering of a built-on-the-membrane light-harvesting antenna from photoluminescent (PL) quantum dots (QDs) which might be able: (1) to harvest light from deep UV to blue region, (2) to convert this energy to photons that can be absorbed by bR or photosynthetic reaction centers (RC) and (3) to transfer this energy to PIMP’s chromophores thus improving biological function. The QD is a unique nanomaterial able to absorb a lot of light from UV to visible region and to convert it in the photons of PL in a narrow spectral region determined by their size. NanoPhotoChrome will combine the nanotechnology and genetic engineering, where genetic engineering develops RC and bR variants with biological functions adapted to specific application and nanotechnology develops QDs specifically selected to be optically coupled with the PIMP chromophores and with surfaces functionalized to form complexes with biomembranes or to be chemically tagged with desired amino acid residues of bR or RC. Such optical and spatial coupling will form efficient energy transfer donor (QD)/acceptor (PIMP chromophore) pairs. The PIMP-QDs nano-units operating in the FRET-regime will provide new hybrid materials with improved biological functions with the advantages of efficiency of light-controlled operation, stability and low cost production