Spectroscopic characterization of porphyrin supramolecular aggregates on poly-lysine and their application to quantitative DNA determination

Using UV-Vis absorption, fluorescence emission and resonance light scatteri ng (RLS) measurements, we have shown that, under the appropriate conditions , a supramolecular complex is formed between the anionic meso-tetrakis(4-su lfonatophenyl)porphine (H2TPPS) and the protonated form of poly-lysine. Suc h assembly is characterized by an almost complete quenching of the porphyri n's fluorescence. The addition of DNA, which is a poly-anion, causes a disp lacement of the porphyrin bound to the poly-cationic matrix with consequent increase in the fluorescence intensity of the solution. Therefore, since t he variation in fluorescence emission is linearly related to the concentrat ion of DNA added, we have investigated the possibility of employing such a supramolecular system in a simple and rapid method for the quantitative det ermination of DNA in solution. (C) 1999 Elsevier Science S.A. All rights re served.