Novel pH-responsive multilayer magnetic nanoparticles for controlled drug delivery

A multifunctional nanocarrier with multilayer core–shell architecture was prepared by chemical modification of Fe 3 O 4 magnetic nanoparticle (MNPs) with acrolein–styrene–polyethyleneimine (AL–St–PEI) via covalent bonding. MNPs were prepared by co-precipitation method, and then, thiol functionalized (MNPs-SH) were synthesized by treating MNPs with the (3-mercaptopropyl) trimethoxysilane. Subsequently, the copolymerization of St and AL was performed in the presence of the MNPs-SH and butyrolactam by thiol-lactam initiated radical polymerization. Finally, PEI was covalently bounded to the aldehyde groups on the surface of AL–St copolymer. The AL–St–PEI MNPs were investigated by FTIR, XRD, TGA, SEM and TEM. The drug release from AL–St–PEI MNPs was evaluated using doxorubicin as the model anticancer. Furthermore, to determine the effect of drug structure in the release profile from the modified MNPs, some lipophilic model drugs were studied in loading and release study. It was found that the nature of the drugs affect the release profile. The in vitro release modeling demonstrated that doxorubicin release is described by zero-order mechanism while release of lipophilic model drugs is controlled by fickian diffusion. Graphical Abstract