Cranioplasty Using a Novel Osteoconductive Scaffold and Platelet Gel.

BACKGROUND: Commonly used materials for cranioplasty include autogenous bone grafts, methyl methacrylate, and titanium mesh. We evaluated a novel osteoconductive scaffold [N-isopropylacrylamide cross-linked with acrylic acid using γ-rays (ANa powder)] mixed with platelet gel for cranioplasty. METHODS: ANa powder mixed with platelet gel was implanted into a 15 × 15-mm, full-thickness calvarial bone defect in 5 New Zealand white rabbits. ANa powder mixed with phosphate-buffered saline was implanted in 5 rabbits. The calvarial bone defect was left unreconstructed in another 5 rabbits. Twelve weeks after surgery, computed tomography examination was used to evaluate the radiographic evidence of bone healing in vivo. Bone specimens were then retrieved for histologic study. RESULTS: The ANa scaffold mixed with platelet gel is biocompatible, biodegradable, and both osteoconductive and osteoinductive, leading to progressive growth of new bone into the calvarial bone defect. CONCLUSION: The use of this novel osteoconductive scaffold combined with osteoinductive platelet gel offers a valuable alternative for the reconstruction of calvarial bone defects.

Stimulation of wound healing by PU/hydrogel composites containing fibroblast growth factor-2.

In this study, polyurethane (PU)/hydrogel composites were fabricated for wound healing applications. The hydrogel is a copolymer of thermosensitive N-isopropyl acrylamide (NIPAAm) and acrylic acid (AAc). γ-ray irradiation was employed to simultaneously copolymerize NIPAAm with AAc and graft the hydrogel onto porous PU. Fibroblast growth factor-2 (FGF-2) was incorporated into the composite to facilitate wound healing. The physical properties of the composites were characterized, the in vitro release of FGF-2 was examined, and in vivo tests were conducted. The results indicate that the thermosensitive hydrogel can absorb most of the wound exudates due to its high water uptake ability. Due to its thermosensitive properties, the PU/hydrogel composite is easier to strip off than that of commercial wound dressing, which prevents additional injury to the wound when replacing the wound dressing. In vivo results show that the PU/hydrogel composite incorporating FGF-2 could accelerate wound healing and reduce scar formation.

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.