Fabrication of sub-cell size "spiky" nanoparticles and their interfaces with biological cells

Chip-based arrays of vertical nanowires (NWs) have attracted biomedical research interest for their one dimensional architecture and cell-interface properties, yet delivery of these devices in solution is not possible due to the inherent attachment of NWs to a planar substrate. To overcome this structural limitation, we report synthesis of hierarchical nanoparticles covered with stiff NWs, namely "spiky particles" which combine the advantages of supported vertical nanowires and aqueous delivery of suspended nanoparticles. ZnO NWs were grown onto SiO₂ nanoparticles using a solution-based synthesis to avoid dispersing particles grown on solid substrates, and increase the particle quantity. These spiky particles can be fabricated with tunable particle and nanowire dimensions. The cell membrane interface with these hierarchical nanostructures were examined using scanning electron microscopy to determine the extent of engulfment and interaction.