Photoabsorption of biomolecules and radiation damage - studies in adenine films

The Layer-by-Layer (LbL) technique has recently been developed as a promising method for production of thin films functional molecular heterostructures since the interactions occurring, essentially ionic and hydrogen bonding patterns, are found to be identical to those observed in biological systems. Such films have been shown to be also potentially good mimics of biological membranes. Also, it is possible that a study of biological relevant molecules assembled in LbL films will provide a closer analogue to their role in cellular systems. Thin films of adenine (A) and the polyelectrolyte poly(vinylsulfonic acid sodium salt) (PVS), were prepared by cast and Layer-by-layer (LbL) techniques. In this article, the experimental results on the UV irradiation of adenine cast films are described and the effect of 140 nm irradiation, with an estimated dose of about 8.5 x 10(-4) W/m(2), is evaluated at the molecular level.