High strength antibacterial membranes consisted of nanofibrous chitosan immobilized silver nanoparticles

Chitosan (CS) has biocompatibility and biodegradability, but the bulk CS hydrogel/membranes with its poor strength and limited antibacterial property could not satisfy the practical application. Here green dissolving/regeneration and in situ reduction strategy was combined to construct high strength antibacterial CS membranes. First nanofibrous CS hydrogels were constructed through dissolving CS in LiOH/KOH/urea aqueous system via freezing-thawing process followed regeneration. Then, Ag NPs were immobilized along CS nanofibers through in situ reductions of Ag + by the NH2 group of CS. The obtained NCM-Ag composite dry membranes are easy for storing and can quick switch to nanofibrous hydrogels as absorbing water. Size of Ag NPs can be controlled to very small until 2 nm by concentration and limited space network. Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer indicated the forceful grasp ability of CS nanofibers to Ag NPs for a stable binding, mechanical property was enhanced over 100Mpa as the nanofibrous structure and chain linked by Ag coordination. The NCM-Ag membranes had excellent antibacterial activities against both Staphylococcus aureus and Escherichia coli. Moreover, such nanofibrous CS membrane exhibited good adhesive ability to tissues. Combining all these properties, NCM-Ag membranes would be potential as antibacterial adhesion barrier to accelerate wound healing.

Automated summary

By combining green dissolving/regeneration and in situ reduction strategy, high strength antibacterial CS membranes were constructed with excellent antibacterial activities and adhesive ability, potentially serving as antibacterial adhesion barrier to accelerate wound healing.