An injectable supramolecular nanofiber-reinforced chitosan hydrogel with antibacterial and anti-inflammatory properties as potential carriers for drug delivery.

The inherent weak mechanical strength of chitosan physical cross-linking hydrogels (CS hydrogels) limits their applications in biomaterials. Hence, puerarin (PUE) as a self-assembly active small molecule in herbal was introduced in CS hydrogels to fabricate CS/PUE composite hydrogels with interpenetrating network structure. The result of rheological measurement showed that storage modulus and loss modulus of CS/PUE composite hydrogels were improved by three orders of magnitude, indicating that the introduction of PUE significantly reinforced CS hydrogels. The results of SEM and BET measurement demonstrated that macromolecular chains of CS intertwined with nanofibers of PUE, which caused the network structure of CS/PUE composite hydrogels to become denser. XRD patterns and FT-IR spectra verified that the amino groups in CS formed hydrogen bonding with the hydroxyl groups in PUE. Degradation and swelling experiments showed that CS/PUE composite hydrogels have pH sensitivity. Moreover, CS/PUE composite hydrogels exhibited multi-functionality including injectability, thixotropy, cytocompatibility, antibacterial and anti-inflammatory properties. The release behavior of berberine chloride hydrate (BCH) and PUE from the resultant CS/PUE composite hydrogels have pH dependence. These results revealed that injectable CS/PUE composite hydrogels with dual antibacterial and anti-inflammatory properties could be potential delivery vehicles for sustained and controlled release.