Peptide-grafted lactide-based poly(ethylene glycol) porous scaffolds for specific cell adhesion

Abstract

While biodegradable polyesters or their copolymers have been used widely as scaffolding materials in tissue engineering, these polymers intrinsically lack the cell-binding motifs on the surface. In this study, a GL-PEG, which is a poly(ethylene glycol) monoacrylate combined with glycerol (G)-lactide (L) triols, was synthesized and fabricated into a porous three dimensional (3D) structure. In addition, peptide ligands, Arg-Gly-Asp (RGD) or Arg-Glu-Asp-Val (REDV) were grafted directly onto the GL-PEG, producing GL-PEG-GRGD and GL-PEG-GREDV scaffolds to improve the specific cell adhesion. Both GL-PEG and GL-PEG-GRDG scaffolds were also prepared as a control. The ESCA spectra showed that peptide-grafted GL-PEG carried a nitrogen peak, which is indicative of the amine group in the peptide sequence. The nitrogen content in the GL-PEG-peptides was significantly higher than that on the the GL-PEG. When the peptide-grafted GL-PEG scaffolds were seeded with fibroblasts and endothelial cells (ECs) and cultured for up to 4 days, specific cell interactions were identified by scanning electron microscopy (SEM). More fibroblasts were found on the GL-PEG-GRGD scaffold but more ECs were found attached to GL-PEGGREDV. The total protein assay also supported the same trend that the fibroblasts/GL-PEG-GRGD or EC/GL-PEGGREDV constructs had the highest protein content with the specific cells, compared with the other groups. This data suggests that cell adhesion could be specific and dependent on the type of peptide ligands. Such 3D porous and crosslinked peptide-grafted GL-PEG scaffolds can be very useful for harboring specific cell populations for tissue engineering and vascular stents.