Synthesis, Characterization, and Study of In Vitro Cytotoxicity of ZnO-Fe3O4 Magnetic Composite Nanoparticles in Human Breast Cancer Cell Line (MDA-MB-231) and Mouse Fibroblast (NIH 3T3).

Novel magnetic composite nanoparticles (MCPs) were successfully synthesized by ex situ conjugation of synthesized ZnO nanoparticles (ZnO NPs) and FeO NPs using trisodium citrate as linker with an aim to retain key properties of both NPs viz. inherent selectivity towards cancerous cell and superparamagnetic nature, respectively, on a single system. Successful characterization of synthesized nanoparticles was done by XRD, TEM, FTIR, and VSM analyses. VSM analysis showed similar magnetic profile of thus obtained MCPs as that of naked FeO NPs with reduction in saturation magnetization to 16.63 emu/g. Also, cell viability inferred from MTT assay showed that MCPs have no significant toxicity towards noncancerous NIH 3T3 cells but impart significant toxicity at similar concentration to breast cancer cell MDA-MB-231. The EC50 value of MCPs on MDA-MB-231 is less than that of naked ZnO NPs on MDA-MB-231, but its toxicity on NIH 3T3 was significantly reduced compared to ZnO NPs. Our hypothesis for this prominent difference in cytotoxicity imparted by MCPs is the synergy of selective cytotoxicity of ZnO nanoparticles via reactive oxygen species (ROS) and exhausting scavenging activity of cancerous cells, which further enhance the cytotoxicity of FeO NPs on cancer cells. This dramatic difference in cytotoxicity shown by the conjugation of magnetic FeO NPs with ZnO NPs should be further studied that might hold great promise for the development of selective and site-specific nanoparticles. Schematic representation of the conjugation, characterization and cytotoxicity analysis of FeO-ZnO magnetic composite particles (MCPs).