Département de chimie moléculaire

A new class of "polymultivalent" ligands combining several ligand clusters and a water-sol. biocompatible polymer is introduced. These original conjugates bear two levels of multivalency. They were prepd. by covalent coupling of a controlled no. of tetrameric cRGD peptide clusters along a well-defined copolymer synthesized by RAFT polymn. The presence of multiple copies of peptide clusters on the same polymer backbone resulted in a much-higher relative potency than the free cluster ref. Thanks to the "polymultivalency", up to ∼2 orders of magnitude potency enhancement was reached in a competitive cell adhesion assay (nanomolar-range IC50 values). In addn., confocal microscopy and flow cytometry demonstrated that fluorescent "polymultivalent" conjugates (emitting in the far-red/near-IR region) were able to specifically and selectively label cells expressing $\alpha$v$\beta$3-integrin, the natural receptor of cRGD. [on SciFinder(R)]