A Photo-Crosslinkable Chitosan Hydrogel for Peripheral Nerve Anastomosis

The predominant therapy for peripheral nerve transection is anastomosis by suture. However, sutures have been known to lead to tissue inflammation, granulomas, and poor functional outcomes. While adhesives offer a promising alternative, fibrin-the predominant bio-glue-can transmit disease. Here we examine a photocrosslinkable chitosan hydrogel for use in surgical therapies for peripheral nerve injury. Prepared by conjugating 4-azidobenzoic acid to amino groups of chitosan using carbodiimide chemistry, this formulation demonstrates a high potential of in-situ photocrosslinking. A 40 mg/mL solution gels under 40 s of UV illumination. This gel is demonstrated to be cytocompatible with neural cell populations and is not acutely toxic to nerve conduction ex vivo. Mechanical testing of nerves anastomosed by this hydrogel had tensile strengths comparable to conventional fibrin glues. These results show chitosan hydrogel to be biocompatible and mechanically suitable for use in nerve repair.