The design of polyvalent scaffolds for targeted delivery.

Nature makes extensive use of polyvalency-the simultaneous binding of multiple ligands to multiple complementary receptors. The concept of polyvalency can also be used to design synthetic scaffolds for applications ranging from the design of inhibitors for toxins and pathogens to delivery and imaging. This article reviews recent developments in the design of polyvalent constructs suitable for targeted delivery. Specifically, we will discuss recent developments in the design of scaffolds, the identification of ligands for targeting, and the presentation of ligands on the scaffold to optimize affinity and specificity for the target.