Human osteoblasts within soft peptide hydrogels promote mineralisation in vitro

Biomaterials that provide three-dimensional support networks for culture of cells are being developed for a wide range of tissue engineering applications including the regeneration of bone. This study explores the potential of the versatile ionic-complementary peptide, FEFEFKFK, for such a purpose as this peptide spontaneously self-assembles into beta-sheet rich fibres that subsequently self-associate to form self-supporting hydrogels. Via simple live/dead cell assays we demonstrated that 3 wt.% hydrogels were optimal for the support of osteoblast cells. We went onto show these cells are not only viable within the 3D hydrogel, but they also proliferate and produce osteogenic key proteins, i.e. they behave like in vivo bone cells, over the 14 day period explored here. The gel elasticity increased over time when cells were present – in comparison to a decrease in control samples - indicating the deposition of matrix throughout the peptide scaffold. Moreover, significant quantities of calcium phosphate were deposited. Collectively, these data demonstrate that ionic-complementary octa-peptides offer a suitable 3D environment for osteoblastic cell function.