Cellular Uptake and Magneto-Hyperthermia Induced Cytotoxicity using Photoluminescent Fe3O4 Nanoparticle/Si Quantum Dot Hybrids

The design and fabrication of Si-based multi-functional nanomaterials for biological and biomedical applications is an active area of research. The potential benefits of using Si-based nanomaterials are not only due to their size/surface-dependent optical responses but also the high biocompatibility and low-toxicity of silicon itself. Combining these characteristics with the magnetic properties of Fe₃O₄ nanoparticles (NPs) multiplies the options available for real-world applications. In the current study, biocompatible magnetofluorescent nano-hybrids have been prepared by covalent linking of Si quantum dots to water-dispersible Fe₃O₄ NPs via dicyclohexylcarbodiimide (DCC) coupling. We explore some of the properties of these magnetofluorescent nano-hybrids as well as evaluate uptake, the potential for cellular toxicity, and the induction of acute cellular oxidative stress in a mast cells-like cell line (RBL-2H3) by heat induction through short-term radio frequency modulation (10 min @ 156 kHz, 500 A). We found that the NPs were internalized readily by the cells and also penetrated the nuclear membrane. Radio frequency activated nano-hybrids also had significantly increased cell death where > 50% of the RBL-2H3 cells were found to be in an apoptotic or necrotic state, and that this was attributable to increased triggering of oxidative cell stress mechanisms.