Conjugation of peptides to a dendrimer surface to promote the proliferation and differentiation of human pluripotent stem cells into cardiomyocytes and retinal pigment epithelium.

Abstract

Human pluripotent stem cells (hPSCs), of which differentiated cells can be used in cell therapy and regenerative medicine, cannot proliferate on traditional polystyrene surfaces. Instead, hPSCs are typically cultivated on surfaces coated with Matrigel, which includes xeno-containing substances. Hence, it is advisable to employ biomaterials conjugated to synthetic peptides to promote hPSCs proliferation. hPSCs have been successfully cultured for more than 10 passages on surfaces conjugated to specific peptides derived from extracellular matrix (ECM) proteins. However, the concentration of peptide solution needed for conjugation is high (typically >1000 μg/mL). To overcome this limitation, novel cell culture biomaterials using a polyamidoamine (PAMAM) dendrimer-based peptide-conjugated surface, which allow high peptide surface density locally, were developed in this study. We successfully cultured hPSCs on a PAMAM dendrimer surface conjugated to a specific peptide designed on the basis of the laminin β4 chain; this surface was generated with a low concentration of peptide (50 μg/mL) that was on the same order of magnitude as that used to coat the surface with ECM solution (5-10 μg/mL). After long-term (10 passages) cultivation on the peptide-conjugated dendrimer surface, hPSCs exhibited pluripotency and the potential to differentiate into cells from all three germ layers, as well as cardiomyocytes for the treatment of myocardial infarction and retinal pigment epithelial cells for the treatment of retinal pigmentosa disease. 3D peptide conjugation (immobilization) at high density on the surface via the PAMAM dendrimer supports maintenance of hPSC pluripotency via low concentrations of peptides during long-term cultivation.