In situ exfoliated silk fibroin nanoribbons enhanced chitin hydrogel for bile duct restoration

The biomaterials exploitation for preventing potential bile leakage caused by the biliary duct injury during hepatobiliary surgery is still challenging. Herein, we developed a"one-pot" method to fabricate the chitin/silk composite hydrogel with superior mechanical properties, biocompatibility and biodegradability via chemically-physically double cross-linked strategy. The resultant hydrogel could be fabricated into bile duct cannula to prevent bile leakage without suturing. The low temperature alkali solvent system simultaneously dissolved the chitin and exfoliated the silk fibroin (SF) into the nanoribbons (SNRs). The in situ exfoliated SNRs served as an enhancement nano-building block to achieve the composite hydrogel with high strength (1.36 Mpa) and toughness (0.71 MJ/m2 of fracture energy). This natural polymer based composite hydrogel exhibited excellent in vitro cytocompatibility when co-cultured with human liver cells and normal human dermal fibroblasts. Moreover, the hydrogel displayed tunable degradability and biochemical properties depending on the degree of bile leakage and thus managed to control the ambient physiological environment around traumatized bile ducts and thus it effectively promoted the bile duct restoration and enhanced the re-vascularization in a rabbit biliary duct injury model. This work provided a whole new perspective for the therapeutic concept of bile duct injury and opened up a new avenue to utilize the natural polymer in the biomedical field.