Calorimetric and Spectroscopic Studies to Monitor the Interaction of L-Cysteine Functionalized Selenium Nanoparticles with Calf Thymus DNA

Abstract

The focus of the study is to understand the interaction between calf thymus DNA and L-Cysteine capped Selenium nanoparticles (cys-SeNPs) using spectroscopic and calorimetric techniques. The size of the nanoparticles was confirmed using transmission electron microscope (TEM). Isothermal titration calorimerty (ITC) provided the binding energy, the number of binding sites and the thermodynamic parameters. UV-Vis absorption and fluorescence quenching studies established the number of binding sites and binding constant. Stabilization of the ct-DNA in the presence of cys-SeNPs was determined from thermal melting studies. It is confirmed by the spectrophotometric titration and calorimetric studies that, selenium nanoparticles can form a complex with the double–helical DNA. The binding constant of cys-SeNPs with the DNA from fluorescence study was found to be 2.953 × 106 M−1 and is consistent with the value obtained from ITC experiment. The binding energies along with the binding sites symbolize the crucial role of van der Waals forces and hydrogen bonds in the binding of cys-SeNPs with ct-DNA.