In vitro evaluation of PEGylated mesoporous MgFe₂O₄ magnetic nanoassemblies (MMNs) for chemo-thermal therapy

A size tunable synthesis of mesoporous MgFe₂O₄ magnetic nanoassemblies (MMNs) through a PEG-diacid mediated polyol method is reported. The PEG-diacid coated MMNs exhibit a significant specific surface area of 92 m² g^-1 and saturation magnetization of 57 emu g^-1. These MMNs exhibit a very good colloidal stability in PBS (pH 7.4) with nonappreciable cytotoxicity in mouse fibroblast (L929) and cervical cancer (HeLa) cells. We demonstrate the potential of MMNs as an integrated nanosystem for drug delivery and magnetic hyperthermia (MHT) through in vitro studies. 80% loading efficiency of doxorubicin (DOX) has been achieved due to the highly negative surface charge and mesoporous nature of MMNs. It is observed that 65-70% of HeLa cells undergo apoptosis through DNA fragmentation after 24 h of incubation with DOX loaded MMNs. MHT alone induces the death of 40-45% of cells, whereas the synergistic effect of a combination of DOX and MHT leads to the death of about 90% of cells. Our results show that MHT significantly increases the therapeutic efficacy of DOX to induce more apoptosis in cancer cells. Hence, a combination of MHT with chemotherapy makes MMNs a powerful multimodal system for synergistic chemo-thermal cancer therapy.