Facile synthesis of nanogels modified Fe₃O₄@Ag NPs for the efficient adsorption of bovine & human serum albumin

This article describes the preparation of Fe₃O₄ nanoparticles and its decoration with a layer of tiny Ag nanoparticles at room temperature. Later on, the synthesized Fe₃O₄@Ag heterostructures were protected with Silica and finally modified with Poly(N-isopropyl acrylamide) (PNIPA) nanogels through post-synthesis method to get multifunctional (superparamagnetic, plasmonic and thermosensitive) nanocomposite. The structural characteristics of Fe₃O₄@Ag@SiO₂–PNIPA nanogels composite were investigated by instrumental techniques such as Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Vibrating Sample Magnetometer (VSM). The average particles diameter was calculated from XRD data through Scherer formula and it was found as 14 nm. The Fe₃O₄@Ag@SiO₂–PNIPA polymeric composites were assessed for the adsorption of Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA) proteins from aqueous media. The adsorption data of BSA and HSA were best explained by Langmuir isotherm model with maximum adsorption capacities of 322 and 166 (mg/g) respectively showing mono-layer adsorption. The kinetics data for both the proteins were fairly interpreted by pseudo-second-order model. Thermodynamics studies revealed that the adsorption phenomena of BSA and HSA on the surface of Fe₃O₄@Ag@SiO₂–PNIPA nanogels composite are spontaneous and exothermic.