Synthesis and Characterization of Multifunctional Interpenetrating Polymer and Its Applications in Protein Adsorption and Magnetite Loading

In this study, we prepared interpenetrating polymers as nanocarrier systems for protein adsorption and superparamagnetic iron oxide nanoparticles (Fe 3 O 4 NPs) loading. Interpenetrating polymer network (IPN) nanogels composed of crosslinked poly (N‐isopropylacrylamide) (PNIPAM) and poly (acrylic acid) (PAA) were firstly prepared, which possessed both pH and thermo‐responsive properties. On the one hand, the model protein (bull serum albumin (BSA)) was loaded into PNIPAM/PAA IPN nanogels. The effect of PAA content on the amount of BSA loading was investigated by controlling the temperatures and pH values. When the adsorption temperature was higher than the lower critical solution temperature (LCST) of PNIPAM and the pH value was lower than the pKa of PAA, it was more conductive to capture BSA. On the other hand, Fe 3 O 4 NPs were encapsulated by in situ redox of iron cations in the interior of PNIPAM/PAA IPN nanogels. As the PAA content in the IPN nanogels increased and attracted more quantity of iron ions, the amount of loaded Fe 3 O 4 NPs increased, which resulted in larger saturation magnetization of the magnetic nanogels but restricted the deswelling behaviors.