A facile one-pot synthesis of poly(acrylic acid)-functionalized magnetic iron oxide nanoparticles for suppressing reactive oxygen species generation and adsorption of biocatalyst

Functionalized iron oxide nanoparticles (IONPs) have unique physical and chemical properties, which make them potential candidates for biomedical applications. In this study, a facile one-pot method is reported for the preparation of poly(acrylic acid) (PAA) functionalized IONPsthrough in situ free radical solution polymerization of AA and subsequent coprecipitation of Fe³⁺ and Fe²⁺ ions. The FTIR spectroscopic and TGA results indicated the successful formation and surface functionalization of IONPs with PAA. Electron micrographs showed that the prepared particles were of nano-sized and their shape is dependent on the concentration of PAA. pH-dependent variation of average hydrodynamic diameter confirmed the pH-responsivity of PAA-functionalized IONPs. Magnetic measurement suggested that the PAA functionalized IONPs were strongly paramagnetic (53.0 emug⁻¹). Fenton-like catalytic generation is carried out to measure toxicity associated with the nanoparticles. The suppression ability for reactive oxygen species (ROS) generation associated with PAA-functionalized IONPs was studied via methylene blue degradation assay to address their toxicity profile. PAA-functionalized IONPs exhibited better suppression ability than that of the bare IONPs. The adsorption behavior of trypsin was also studied at different pH levels and a maximum adsorption is occurred on PAA-functionalized IONPs at pH 5.0. Catalytic behavior study confirmed higher activity of trypsin immobilized on PAA-functionalized IONPs than that of the reference IONPs. Therefore, the functionalized IONPs can be of high interest for magnetically recyclable biocatalyst carrier. (paper)