Conformational Transitions in Silver Nanoparticals: DNA and Photoirradiation

TL;DR

This study investigates how photoirradiation affects silver nanoparticles in water, especially when bound to DNA, revealing desorption and oxidation processes with implications for cancer therapy.

Contribution

It provides new insights into the photo-induced desorption and oxidation mechanisms of silver nanoparticles in DNA solutions, with kinetic parameters estimated.

Findings

Photoirradiation causes desorption of silver atoms from AgNPs-DNA complexes.

An isosbestic point indicates a distinct complex formation.

Kinetic parameters for desorption and oxidation are estimated.

Abstract

Photoirradiation of silver nanoparticles in water solution of NaNO3 (0.01M) and in dissolved DNA was investigated by spectrophotometric and thermodynamic kinetic approaches. It is shown that only the irradiated complexes AgNPs-DNA have distinctly expressed isosbestic point. The test with the free AgNPs demonstrates that as a result of photo-irradiation desorption of silver atoms and their oxidation takes place. We have also observed that at photo-irradiation of the complexes by AgNPs-DNA desorption of silver atoms from the surface of AgNPs takes place. Kinetic study of photo-desorption of silver atoms has allowed to estimate desorption rate constant and the heat of adsorption for free AgNPs and AgNPs bound with DNA. On DNA example toxicity of AgNPs at their application to photo-chemo and photo-thermo therapy of cancer is discussed.