Fabrication of platelet-rich plasma heparin sulfate/hydroxyapatite/zirconia scaffold

Hydroxyapatite (HA) has been successfully coated on zirconia (ZrO₂) to construct a porous scaffold with higher mechanical strength, but there are still big challenges regarding the delivery of osteogenic growth factors (GFs), local reserve and their sustained release. In this study, the authors fabricated a porous interconnected HA/zirconia scaffold by slurry method with 71·6 ± 0·5% porosity and 310 ± 150 μm pore size. Platelet-rich plasma (PRP) was used as a source of GFs, and heparin sulfate (HS) sequestrated them. After activating PRP with 2·5% calcium chloride (CaCl₂), 5 μg/ml of HS was added and mixed well, followed by impregnation into the porous HA/zirconia scaffold. The PRP/HS-containing scaffolds showed a significantly higher mechanical strength. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability test demonstrated a significantly higher proliferation rate on the PRP/HS-containing scaffolds compared to those without PRP/HS. Culturing MG-63 cell line showed that 100% of cells attached to the PRP/HS-containing scaffolds compared with HA/zirconia ones. The cells also showed a significantly higher alkaline phosphatase activity and calcium mineralization in scaffolds treated with PRP/HS. The scaffolds with PRP/HS seem to provide a superior microenvironment for osteoblast activities and can be suggested as a good vehicle for growth factor and cell delivery in bone tissue engineering applications.