Authors: A. Tibuzzi, G. Pezzotti, G. Rea, D. Bianconi and M.T. Giardi
Affilation: Biosensor S.r.l., Italy
Pages: 519 - 522
Keywords: reaction centres, photosynthesis, amperometric detection, oxidants, immobilisation
The goal of this work is the development of specific and sensitive biosensors for the measure of anti-oxidizing agents power, by exploiting the property of Reaction Centres complexes (RCs) to specifically recognize oxidizing chemicals (e.g. H2O2, NO), whose interaction produces changes in RCs physiological activities, such as the light-induced electron transfer. The sensor is based on the amperometric transduction of this chemical interaction into a current/voltage signal, by coupling the biological material with screen-printed electrodes. RC-complexes with different sensitivity and selectivity to oxidants have been extracted from bacteria (Rodobacter sphaeroides), cyanobacteria (Synecococcus elongatus), algae (Chlamydomonas reinhardtii) and higher plants (Spinacea oleracea). Different mutants of the C. reinhardtii D1 protein have been also genetically produced and RCs-hybrids with organic and inorganic compounds have been implemented (immobilisations with magnetic beads and TiO2 nanoparticles). The modular measurement cell is made up by two excitation LEDs (430, 630nm) and a flow channel. Experimental measurements aiming at calibrating the system with known concentrations of antioxidants have been performed and preliminary results show a reduction of the measured light-induced current in the RC samples with a non linear dependence on oxidants concentration. Targeted applications belong to the agro-food, pharmaceutical and biomedical fields.