Green synthesis of silver nanoparticles from Delonix regia leaf extracts: In-vitro cytotoxicity and interaction studies with bovine serum albumin

Abstract

Biogenic synthesis is an effective, nontoxic, clean, eco-friendly and cost-effective green chemistry approach to synthesize metal nanoparticles having significant properties and applications in various fields. Herein, we have approached an environment-friendly protocol for the biogenic synthesis of silver nanoparticles (AgNPs) using Delonix regia (D. regia) leaf aqueous extract as bio-reducing and capping agent. The initial reaction progress was observed by the colour change in the reaction mixture and the AgNPs formation was confirmed by the appearance of surface resonance plasmon (SRP) band at 455 nm by UV–visible spectroscopy. The morphology of the biosynthesized AgNPs was further confirmed by using different techniques such as transmission electron microscopy (TEM), selected area electron diffraction (SAED) and scanning electron microscopy (SEM). The crystalline nature of the biogenic AgNPs was analyzed by X-ray diffraction (XRD) technique. We have further shown the in-vitro cytotoxicity of biogenic AgNPs against A459 and SiHa cell line. We have also investigated the esterase like activity of BSA with synthesized AgNPs. Fluorescence results suggested the contribution of static quenching in the complex formation between AgNPs and BSA. The AgNPs are seen to interact with BSA effectively resulting in structural changes of BSA confirmed by far UV-CD and FT-IR techniques.