A Novel Porous Butyryl Chitin-Animal Derived Hydroxyapatite Composite Scaffold for Cranial Bone Defect Repair.

Bone defects, a common orthopedic problem in clinical practice, are a serious threat to human health. As alternative materials to autologous bone grafts, synthetic cell-free functionalized scaffolds have been the focus of recent research in designing scaffolds for bone tissue engineering. Butyryl chitin (BC) is a derivative of chitin (CT) with improved solubility. It has good biocompatibility, but few studies have investigated its use in bone repair. In this study, BC was successfully synthesized with a degree of substitution of 2.1. BC films were prepared using the cast film method and showed strong tensile strength (47.8 ± 4.54 N) and hydrophobicity (86.4 ± 2.46°), which was favorable for mineral deposition. An in vitro cytological assay confirmed the excellent cell attachment and cytocompatibility of the BC film; meanwhile, in vivo degradation indicated the good biocompatibility of BC. Hydroxyapatite (HA), extracted from bovine cancellous bone, had good cytocompatibility and osteogenic induction activity for the mouse osteoblast cell line MC3T3-E1. With the aim of combining the advantages of BC and HA, a BC-HA composite scaffold, with a good pore structure and mechanical strength, was prepared by physical mixing. Administered into skull defects of rats, the scaffolds showed perfect bone-binding performance and effective structural support, and significantly promoted the regeneration of new bone. These results prove that the BC-HA porous scaffold is a successful bone tissue engineering scaffold and has strong potential to be further developed as a substitute for bone transplantation.

Study on repair of abdominal wall defect rats with hernia mesh coated with chitosan-based photosensitive hydrogel.

Herein, hydroxypropyl chitosan azide (AZ-HPCTS) was synthesized and prepared as a hydrogel coating applied to a polypropylene mesh (PPM) through UV irradiation. This study confirmed the hypothesis that hydrogels with porous three-dimensional network structures exhibited excellent biocompatibility and biodegradability and adhered well to PPM. During the 180-day follow-up period, the AZ-HPCTS-coated PPM (AH-PPM) promoted wound healing by promoting the secretion of transforming growth factor-beta1 (TGF-beta1) in the acute reaction stage, which was reduced to a lower level at 30 d. The PPM exhibited a lower fibrin lysozyme activity based on the expression of tissue plasminogen activator (tPA) compared with that of AH-PPM (P < 0.05). The intraperitoneal adhesion score of AH-PPM decreased to 2.4 at 180 d in contrast with PPM (P < 0.01), which remained at a high level throughout the study. In conclusion, the AZ-HPCTS hydrogel is a potential coating for hernia patches that deserves further study in the biomaterial field.