Ligand-clustered "patchy" nanoparticles for modulated cellular uptake and in vivo tumor targeting.

Despite the evident success of using a multivalent approach to increase efficacy of targeted delivery, a clear understanding of how multiple ligands behave collectively to influence the uptake of nanoparticle cell-targeting agents has not been reached. Although when present in large quantity, multivalent ligands can increase binding avidities to cells, it is also conceivable, that the manner in which these ligands are presented to the cell may have a significant effect on uptake. Here we examine this parameter using a linear dendritic polymer construct that enabled us to pattern the surfaces of nanoparticles with variable sized ligand clusters in different spatial arrangements. We demonstrate for the first time the clear impact of folate presentation on intracellular uptake both in vitro and in vivo. The findings presented here suggest that the nature of ligand presentation on a nanoparticle surface may play an important role in drug targeting; the results suggest potential impact for other targeting moieties and provide a framework for further refinement of future multivalent targeting strategies.