Endogenous Activation-Induced Delivery of a Bioactive Photosensitizer from a Micellar Carrier to Natural DNA

Abstract

Photophysics of phenosafranin (PSF), a member of the photosensitizer phenazinium family, has been explored in non-ionic Triton X-165 (TX-165) micelle, calf thymus DNA (ctDNA) and a composite environment consisting of both the micelle and the DNA, using diverse spectroscopic techniques of both steady state and time resolved nature to divulge the binding interaction of the probe with the different hosts. Vivid experimental results demonstrate that PSF binds with both the micelle and the DNA, the binding affinity of the probe, however, is much higher towards the DNA. The micelle carried PSF when comes in the proximity of ctDNA, it gets released from the micellar environment to be intercalated in the DNA base pairs. An endogenous activation in terms of a higher binding affinity of PSF towards ctDNA relative to that with the micelle is ascribed to be responsible for this transfer. The article, thus, demonstrates an endogenous transfer of a bioactive molecular probe from a micellar nanocarrier to the natural DNA. Since the carrier micelle (TX-165) does not perturb the structure of the DNA, the work proposes that it can be promisingly used for the purpose of safe delivery of drugs. The study is expected to stimulate the generation and/or search for advanced micelle based carrier systems for delivery of bioactive molecular systems to the biological targets like DNA.