Ligand-conjugated quantum dots for targeted drug delivery to nerve cells

Increased interest in nanoparticle quantum dots as fluorescent probes possessing extended photostability, multi-color capability, and surface-controllable properties has made apparent their promising potential for biological and therapeutic applications. As an approach towards surface-functionalized nanoparticle drug delivery, here we report the development of quantum dots (QDs) complexed with the small peptide hormone /spl beta/NGF. Surface modification and composition of ligand-conjugated QDs were confirmed using atomic force microscopy. Bioactivity and visual localization of ligand-QD complexes was assayed in live cells. Despite known structural and chemical stringency of ligand-receptor activation, we provide evidence to support activation of cell-surface trkA membrane receptor channels and downstream modulation of neurite sprouting. This QD-based capability bears significance for development of surface-conjugated nanoparticle drug delivery.