The compositions and methods of the present invention relate to the co-delivery of a molecule and a polypeptide to cells to improve the therapeutic efficacy of the molecules. In one embodiment of the invention, the invention may improve delivery of growth factors by co-delivering these growth factors with their receptors and co-receptors, such as syndecans. Co-delivery of growth factors with syndecans, for example, may protect growth factors from proteolysis, enhance their activity, and target the growth factors to the cell surface to facilitate growth factor signaling. This novel approach to growth factor therapy could be extended to other systems and growth factors enabling the enhancement of multiple signaling pathways to achieve a desired therapeutic outcome.
