Cyclodextrin induced controlled delivery of a biological photosensitizer from a nanocarrier to DNA

Abstract

In this article, we have addressed to a demanding physicochemical aspect of therapeutic and drug research. We have reported a simple yet prospective technique that can be exploited for the controlled delivery of drugs and/or bioactive small molecules to the most relevant biomolecular target DNA. Exploiting various steady state and time resolved spectroscopic techniques together with the DNA helix melting study, we have shown that a biologically significant photosensitizer, namely, phenosafranin (PSF), can be quantitatively transferred to the DNA from the micellar nanocarrier made up of sodium tetradecyl sulfate (STS) using the external stimulant β-cyclodextrin (β-CD). The complexation property of β-CD with the nanocarrier (STS) has been utilized for the controlled release of the probe from the micelle to the DNA. Non-toxicity of the stimulant and the noninvasive nature of the carrier towards the target are expected to add to the suitability of this approach from a clinical perspective.

A promising strategy for improved solubilization of ionic drugs simply by electrostatic pushing

“…The steady state absorption spectrum of PSF in aqueous medium shows a low energy unstructured broad absorption band with a maximum at 520 nm. 22,40 Upon increasing the SDS concentration, the absorbance of PSF slightly increases with a noteworthy red shi ($10 nm) of the absorption maximum (gure not shown), suggesting the probe-micelle interaction. 41,42 Upon excited at 520 nm, room temperature emission spectrum of PSF in aqueous solution shows a single and unstructured emission band with a maximum at $582 nm, ascribed to the charge transfer (CT) emission.…”

“…Being sensitive to the environment and excited state interactions, uorescence lifetime serves as an important parameter to identify precisely the residence of a probe in a microheterogeneous assembly. 22,32,36,40,41,[50][51][52][53] The uorescence decay proles of PSF with increasing concentration of SDS are provided in Fig. S3 in the ESI † and the corresponding deconvoluted lifetime data are tabulated in Table S1.…”

“…Micelles can enhance the solubility and hence the bioavailability of a variety of drugs and release the payload preferentially at the target site in response to biological stimuli by means of enhanced permeation and retention effect. 8,[21][22][23][24] The extent of solubilization of the drugs into the micellar nanocavity depends on micellar size, aggregation number and the nature of the solute. 25 Partitioning of the drugs between the micelles and the target site controls the sustained release of the drugs from the micellar systems.…”

“…26 Recent studies on a variety of drugs/dyes with various surfactants enlighten our understanding of the probe-micelle binding interaction and the distribution and/or localization of the probes within the micellar environments. 22,[27][28][29] There is, however, another possibility of enhancing the drug efficacy: if the drug molecules can be solubilized more in the target site by some means. This is expected to increase the contact area of the drugs with the target system as well as enhance the concentration of the drug in the target region, resulting in an enhanced efficacy.…”

“…31,32,[34][35][36][37][38] In one of our recent studies, we have shown the quantitative release of PSF from an anionic micellar carrier to natural DNA by exogenous means. 22 In the present work, our objective has been to investigate the effect of different salts on the solubilization of a cationic probe (PSF) within anionic SDS micelle, with a special interest to explore if salts can be exploited for improved cellular internalization of the ionic drugs. To establish the strategy of electrostatic pushing, we have investigated the effect of different salts of varying charge density on the cationic PSF bound to the SDS micelle.…”