| Wounds and burns cause large skin defects and often form wounds that are difficult to heal,which not only affect the integrity of skin tissue,but also significantly increase the risk of bacterial infection.Therefore,based on the polysaccharides and proteins of natural extracellular matrix(ECM)with excellent biocompatibility and the free radical generation of semiconductors excited by visible light,a semiconductor nanoparticles-doped biomimetic cell matrix antibacterial hydrogel with excellent injection performance,rapid in-situ gelation,suitable degradation rate and good cell biocompatibility was designed in this paper.The main research contents and results are as follows:Firstly,the gelatin was modified by methacrylic acid and carbohydrazide to form Gelma-CDH,and then the oxidized sodium alginate(OSA)and Gelma-CDH were formed into double-network hydrogel GCOA according to Schiff base reaction and free radical polymerization.At the same time,zeolite imidazolyl ester frame-8(ZIF-8)and gold nanoparticles(Au NPs,15nm)were used to form Au@ZIF-8 hybrid particles with core-shell structure.Compared with pristine ZIF-8,Au@ZIF-8 has more efficient production of reactive oxygen species(ROS)under the excitation of visible light(>400nm)owing to its reinforced light absorption and charge carrier separation by the Au-mediated surface plasmon resonance and Schottky junction.Finally,the positively charged Au@ZIF-8 was loaded into the negatively charged GCOA hydrogel to form organic semiconductor nanoparticle composite hydrogel(Au@ZIF-8@GCOA).The properties of particles and hydrogels were characterized by UV-Vis absorption spectra detection,X-ray photoelectron spectra detection,Fourier transform infrared spectroscopy,~1H NMR,and field emission scanning electron microscope.The antibacterial experiment in vitro showed that the Au@ZIF-8@GCOA hydrogel exhibited remarkable bactericidal activity against both Escherichia coli and Staphylococcus aureus under visible light irradiation(20 min).In vitro cell experiments including CCK-8 assay and confocal microscopy showed that Au@ZIF-8@GCOA hydrogel had excellent cell adhesion promoting property and cell compatibility.Animal experiments showed that in situ injection of Au@ZIF-8@GCOA hydrogel into the mouse skin wound bacterial infection model could effectively eradicate the bacteria in the skin tissue under visible light irradiation,reducing the inflammatory reaction and accelerating the healing process of the skin tissue.Therefore,Au@ZIF-8@GCOA hydrogel showed excellent antibacterial activities and enhanced accelerated wound healing under visible light irradiation.This study provides a new idea for the development of functional materials for wound skin repair. |
