Comparative interaction of silver nanoparticles with diverse classes of proteins: Selectivity toward silk sericin...

Nanotechnology, which investigates matter at the 1-100 nm scale, has led to significant advancements, particularly in biomedical sciences. Among nanomaterials, silver nanoparticles (AgNPs) stand out due to their unique physicochemical properties and promising biological applications. However, the mechanisms underlying AgNPs' interactions with biological molecules-especially proteins-remain key questions. In this study, we examined AgNPs interactions with various protein classes, including bovine serum albumin, bovine hemoglobin, α-amylase, and sericin from Antheraea assama. AgNPs were synthesized and characterized using powder X-ray diffraction, high-resolution transmission electron microscopy, and Zeta Sizer, revealing a crystal size of 15 nm and a zeta potential of -24.4 mV. Techniques such as UV-visible, fluorescence, circular dichroism, time-resolved fluorescence spectroscopy, isothermal titration calorimetry, molecular docking, and enzyme kinetics were used to study AgNPs-protein interactions. Our results showed simultaneous adsorption, secondary structure changes, and enhanced enzyme activity upon AgNPs binding. Notably, sericin, a random coil protein, exhibited dynamic quenching at lower AgNPs concentrations and static quenching at higher concentrations, along with thermodynamically favorable binding and hard corona formation, surrounded by dynamic outer layers due to weak protein-protein interactions. These findings emphasize the need to understand diverse biomolecular interactions before employing AgNPs in biomedical applications.