Attachment, proliferation, and migration of marrow stromal osteoblasts cultured on biomimetic hydrogels modified with an osteopontin-derived peptide

We prepared oligo(poly(ethylene glycol) fumarate) (OPF) hydrogels modified with a rat osteopontin-derived peptide (ODP), Asp-Val-Asp-Val-Pro-Asp-Gly-Arg- Gly-Asp-Ser-Leu-Ala-Try-Gly (DVDVPDGRGDSLAYG), as well as Gly-Arg-Gly-Asp-Ser (GRGDS) and investigated the modulation of marrow stromal osteoblast function on the peptide-modified hydrogels. Osteoblast attachment was competitively inhibited by a soluble peptide suggesting that the interaction of osteoblasts with the hydrogel was ligand specific. The proliferation index of osteoblasts relative to the initial seeding density was similar on the hydrogels modified with ODP (1.18±0.13) and GRGDS (1.27±0.12). However, fibroblasts proliferated faster on GRGDS-modified hydrogels than on ODP-modified hydrogels as evidenced by the proliferation indices of 4.89±0.03 and 2.42±0.16, respectively. A megacolony migration assay conducted for 3 days with a seeding density of 53,000cells/cm² showed that osteoblasts migrated to a longer distance on ODP-modified hydrogels (0.23±0.06mm/day) than on hydrogels modified with GRGDS (0.15±0.02mm/day). In addition, osteoblasts migrated faster than fibroblasts seeded at the same density on ODP-modified hydrogels (0.15±0.11mm/day). The migration of osteoblasts on the peptide-modified hydrogels was dependent on the peptide concentration of the hydrogels resulting in an increased migration distance with increasing the peptide concentration for the concentrations tested. These results show that OPF-based biomimetic hydrogels hold promise for modulating cell proliferation and migration for specific applications by altering the specific ligand and its concentration in the hydrogels.