Bio-Organic hybrid photoconverters

Humankind is in great need of new energy sources. The use of solar radiation for powering the planet would fulfil the energy requirements of Earth's inhabitants as well as greatly mitigate tension flares arising from the uneven distribution of fossil fuels and environmental problems associated to their extraction procedures. How to proceed than? Easy to say! Mother Nature is inspiring: all life on earth is based on the conversion of the solar radiation into high energy molecules, including gas and oil human beings are consuming these days, by mean of the so-called primary photoconverters, i.e. the photosynthetic organisms, plants, algae and some kind of bacteria. So, let's learn from Nature and assemble in our laboratories artificial systems capable of exploiting solar energy for photocatalysis and electrical energy production [1], i.e. mimic photosynthesis. Not an easy task of course, but a large number of laboratory are heavily involved since the last 25 years in the field of artificial photosynthesis and are obtaining encouraging results. The photosynthetic apparatus used by photosynthetic organisms to convert solar energy and drive their metabolism is the photochemical core where photoconversion takes place, and is constituted by a protein portion allocating several pigments directly involved in the harvesting of solar light and in the subsequent sequence of electron transfer reactions which eventually lead to the formation of an electron-hole couple to be used for any energy requiring process. In artificial photosynthesis the role of the protein scaffold in often ignored and attention is devoted to assembly molecular system for optimising light harvest and electron-transfer reactions, focussing to the "less-complex" portion of the photosynthetic apparatus [2]. What would be a different paradigm in artificial photosynthesis? Assemble artificial photoconverters using genuine natural components formed by hybrid organic-biologic systems [3]. The hybrids have a central protein, the so-called photosynthetic reaction center (RC) that converts sunlight into a charge-separated state having a lifetime sufficient to allow ancillary chemistry to take place. The RCs can be eventually garnished with opportune organic moieties to be used for different applications [4,5]. The state of the art of these hybrid organic-biologic photosynthetic assemblies will be reviewed.