The enhancement of osteoblast growth and differentiation in vitro on a peptide hydrogel-polyHIPE polymer hybrid material.

The objective of this study was to investigate the effect of combining two biomaterials on osteoblast proliferation, differentiation and mineralised matrix formation in vitro. The first biomaterial has a well-defined architecture and is known as PolyHIPE polymer (PHP). The second biomaterial is a biologically inspired self-assembling peptide hydrogel (RAD16-I, also called PuraMatrix) that produces a nanoscale environment similar to native extracellular matrix (ECM). Our work investigates the effect of combining RAD16-I with two types of PHP (HA (Hydroxyapatite)-PHP and H (Hydrophobic)-PHP) and evaluates effects on osteoblast growth and differentiation. Results demonstrated successful incorporation of RAD16-I into both types of PHP. Osteoblasts were observed to form multicellular layers on the combined biomaterial surface and also within the scaffold. Dynamic cell seeding and culturing techniques were compared to static seeding methods and produced a more even distribution of cells throughout the constructs. Cells were found to penetrate the scaffold to a maximum depth of 3 mm after 35 days in culture. There was a significant increase in cell number in H-PHP constructs coated with RAD16-I compared to H-PHP alone. Our results show that RAD16-I enhances osteoblast differentiation and indicates that the incorporation of this peptide provides a more permissive environment for osteoblast growth. We have developed a microcellular polymer containing a nanoscale environment to enhance cell: biomaterial interactions and promote osteoblast growth in vitro.