<p>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 Fe<sub>3</sub>O<sub>4</sub>
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 Fe<sub>3</sub>O<sub>4</sub> NPs <i>via</i> 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. </p>
