Porous PVA/SA/HA hydrogels fabricated by dual-crosslinking method for bone tissue engineering

In the present work, a new kind of porous polyvinyl alcohol/sodium alginate/hydroxyapatite (PVA/SA/HA) composite hydrogels with tunable structure and mechanical properties have been fabricated by dual-crosslinking method. The morphologies, moisture content, porosity and mechanical properties of the composite hydrogels have been investigated in detail. The PVA/SA/HA hydrogels present uniform, interpenetrating porous structure. The FTIR and XRD results indicate that PVA, SA and HA could be uniformly compounded. The mechanical properties, moisture content and porosity of the samples could be controlled by changing the mass ratio of PVA/SA/HA. The optimized compression modulus (41.74 +/- 7.86 kPa), moisture content (86.99 +/- 0.72%) and porosity (79.98 +/- 1.61%) of the composite hydrogels could be achieved via fixing the weight ratio of PVA/SA/HA at 42:18:40. In vitro biodegradation and mineralization of the composite hydrogels show that the hydrogels could gradually be degraded in PBS solution and sheet-like HA nanocrystals are easily formed on the surface. Moreover, cell culture results indicate that the PVA/SA/HA hydrogels have no negative effects on MC3T3-E1 cell growth and proliferation. Alkaline phosphatase (ALP) activity expressions demonstrate that the nano-HA crystals incorporated composite hydrogels obviously improve the ALP activity of the cells. It confirms that the prepared PVA/SA/HA hydrogels could be a promising candidate for bone repair and bone tissue engineering.