Sub-Cell Size Spiky Nanoparticles for Drug Delivery

Array of high aspect-ratio nanowires (NWs) have attracted great interest for biomedical research owing to their one dimensional architecture and unique properties, yet bio-applications with solution-based delivery, such as neccessary in vivo, are limited due to the inherent attachment of NWs to a planar substrate. Celluar uptake of free NWs through endocytosis generally suffers from ineffective endosomal escape and low efficiency of cytosolic access. Here we explore synthesis of nanoparticles covered with stiff NWs, namely "spiky particles", which combine the advantages of NWs' cell penetration capability, and aqueous delivery of suspended nanoparticles. In this work, ZnO NWs covering suspended SiO₂ nanoparticles were developed using a solution-based synthesis approach. These spiky particles can be fabricated with tunable dimensions or sizes, and were successfully dispersed in solution, a challenge for other solid-phase synthesis techniques. Possible applications for materials delivery to cells was explored including the cell-particle interface, spiky particle cytotoxicity, and spiky particle-mediated DNA transfection.