Novel naturally crosslinked electrospun nanofibrous chitosan mats for guided bone regeneration membranes: material characterization and cytocompatibility.

Guided bone regeneration (GBR) barrier membranes are used to prevent soft tissue infiltration into the graft space during dental procedures that involve bone grafting. Chitosan materials have shown promise as GBR barrier membranes, due to their biocompatibility and predictable biodegradability, but degradation rates may still be too high for clinical applications. In this study, chitosan GBR membranes were electrospun using chitosan (70% deacetylated, 312 kDa, 5.5 w/v%), with or without the addition of 5 or 10 mm genipin, a natural crosslinking agent, in order to extend the degradation to meet the clinical target time frame of 4-6 months. Membranes were evaluated for fibre diameter, tensile strength, biodegradation rate, bond structure and cytocompatibility. Genipin addition, at 5 or 10 mm, resulted in median fibre diameters 184, 144 and 154 nm for uncrosslinked, 5 mm and 10 mm crosslinked, respectively. Crosslinking, examined by Fourier transform infrared spectroscopy, showed a decrease in N-H stretch as genipin levels were increased. Genipin-crosslinked mats exhibited only 22% degradation based on mass loss, as compared to 34% for uncrosslinked mats at 16 weeks in vitro. The ultimate tensile strength of the mats was increased by 165% to 32 MPa with 10 mm crosslinking as compared to the uncrosslinked mats. Finally, genipin-crosslinked mats supported the proliferation of SAOS-2 cells in a 5 day growth study, similar to uncrosslinked mats. These results suggest that electrospun chitosan mats may benefit from genipin crosslinking and have the potential to meet clinical degradation time frames for GBR applications.

Evaluation of biocompatibility and degradation of chitosan nanofiber membrane crosslinked with genipin.

Chitosan, a natural polysaccharide, has demonstrated potential as a degradable biocompatible guided bone regeneration membrane. This study aimed to evaluate the in vivo biocompatibility and degradation of chitosan nanofiber membranes, with and without genipin crosslinking as compared with a commercial collagen membrane in rat model. Chitosan nanofiber membranes, with and without genipin crosslinking, and collagen membrane (control) were implanted subcutaneously in the backs of 30 rats. The membranes were analyzed histologically at 2, 4, 8, 12, 16, and 20 weeks. Sections were viewed and graded by a blinded pathologist using a 4-point scoring system (0 = absent, 1 = mild, 2 = moderate, and 3 = severe) to determine the tissue reaction to the membranes and to observe membrane degradation. There was no statistically significant difference in histological scores among chitosan and collagen membranes at different time points. Absence or minimal inflammation was observed in 57-74% of the membranes across all groups. Most chitosan membranes persisted for 16-20 weeks, whereas most collagen membranes disappeared by resorption at 12-16 weeks. The general tissue response to chitosan nanofiber membranes with and without genipin crosslinking, was similar to that of control commercial collagen membrane. However, the chitosan membranes exhibited slower degradation rates than collagen membranes.