Poly(acrylic acid)-chitosan-silica hydrogels carrying platelet gels for bone defect repair

Most hydrogels derived from either natural or synthetic sources suffer from the lack of mechanical strength. In this study, high strength poly(acrylic acid)-chitosan-silica (PAA-Ch-Si) hydrogels were prepared by UV polymerization for tissue engineering applications. Compressive strength up to 42 MPa can be achieved by the formation of an interpenetrating network (IPN) structure between PAA and chitosan with nano-silica as the filler. The preliminary cell culture of osteoblast cells (7F2) on PAA-Ch-Si hydrogels indicates good biological safety. The growth factor (platelet glue) is fast and completely released from PAA-Ch-Si hydrogel scaffolds within 620 min. The scaffold starts to degrade after eight months in vitro. Histological examinations demonstrate that the hydrogel incorporated with growth factors and osteoblast cells can promote cell migration. All these results illustrate that PAA-Ch-Si hydrogels are beneficial for tissue engineering applications and can be used as scaffolds for bone defect repair.