The Effects of ultraviolet irradiation on hybrid films of photosynthetic reaction centers and quantum dots in various organic matrices

Resumo

The effects of ultraviolet radiation (up to 0.6 J/cm²) on the absorption spectra and electron transfer in dehydrated films of photosynthetic reaction centers from purple bacteria Rb. sphaeroides and hybrid structures that included reaction centers, quantum dots, and protein structure stabilizers (trehalose, polyvinyl alcohol, and methylcellulose) have been studied. Ultraviolet irradiation led to partial destruction of bacteriochlorophyll molecules (pheophytinization) and the reaction center carotenoid. In this case, ultraviolet irradiation did not exert a significant effect on electron transfer between the photoactive bacteriochlorophyll and quinone electron acceptors. The incorporation of reaction centers into organic matrices reduced pheophytinization. Trehalose was the most efficient in reducing the damage evoked by ultraviolet irradiation of the carotenoid molecule. Hybrid films that contained quantum dots were resistant to pheophytinization upon ultraviolet irradiation, but the presence of quantum dots did not affect the processes of carotenoid destruction upon exposure to ultraviolet radiation. Ultraviolet radiation had an insignificant effect on the characteristics of quantum dots (the fluorescence lifetime).