Excitation Energy Migration of Acridine Orange Intercalated into Deoxyribonucleic Acid Thin Films

Abstract

The excitation energy migration of acridine orange (AO) immobilized in deoxyribonucleic acid (DNA) thin film was investigated by time-resolved fluorescence and fluorescence anisotropy decay measurements. Polyvinylalcohol (PVA) was used as a reference matrix. The absorption and fluorescence spectra indicated that the molecular aggregation was depressed in DNA thin films rather than in PVA thin films. Time-resolved fluorescence spectra of AO in DNA films suggested effcient energy transfer from monomer to trap sites, dimers, or aggregates. Fluorescence lifetime of AO in DNA films was decreased with increasing fractions of AO, which suggested efficient energy migration between intercalated AOs. The fluorescence anisotropy measurements directly supported the efficient energy migration between intercalated AOs. These findings indicate that the double-helix DNA contributes to the efficient energy migration between intercalated dyes.