Optimized Synthesis and Stabilization of Superparamagnetic Iron Oxide Nanoparticles for Enhanced Biomolecule Adsorption.

Monodisperse and colloidally stable magnetic iron oxide nanoparticles have been developed for diverse biotechnology applications. Although promising for the adsorption of organic molecules, the low density of adsorption sites in these nanoparticles has been a significant challenge. In this study, an optimized factorial design with response surface methodology (RSM) was employed to produce small Superparamagnetic Iron Oxide Nanoparticles (SPIONs) stabilized with tetraethoxysilane (TEOS). Bovine Serum Albumin (BSA) was selected for immobilization on the surface of SPIONs to test adsorption capacity. The model was validated by correlating significant factors with experimental responses, enabling the prediction of the smallest nanoparticle size. We obtained superparamagnetic SPIONs (75.12 emu/g) with high surface area and an average diameter of 11.06 ± 0.84 nm, with stability improved by the adsorption of TEOS (-46.24 mV) and suitable for pH values from 2 to 10 and salt concentrations up to 1 M. The maximum adsorption capacity of the nanoparticles was 87.8 ± 1.79 mg of BSA per gram of nanoparticles. The nanomaterial synthesized here presents a favorable platform for anchoring protein molecules via silanol groups on its electrostatically charged surface. This study introduces an effective strategy for the synthesis and stabilization of SPIONs with potential biotechnology applications.