Surface amino-rich GQDs-ε-PL is prepared by changing the addition amount of ε-PL. Then, GQDs-ε-PL@4-arm PEG-BA/QCS hydrogels (GQDs-ε-PL@Gel) are synthesized through dynamic imine bonds cross-linking. The sol can transform quickly to gel and the gelation time can be controlled by adjusting the specific gravity of the input raw materials to water. FT-IR and thermogravimetric analyses indicate the successful synthesis of GQDs-ε-PL and GQDs-ε-PL@Gel. The microstructure observation reveals that GQDs-ε-PL has a sheet-like structure with an average size of 65 nm, while GQDs-ε-PL@Gel has a porous network structure. Both GQDs-ε-PL and GQDs-ε-PL@Gel have good fluorescence stability, photothermal and cytocompatibility, and display better antibacterial effect against Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa through chemical and photothermal synergistic sterilization. More importantly, GQDs-ε-PL@Gel can repeatedly self-heal after being damaged, which is more beneficial to provide an effective wound closure environment for wounds and to be used as wound dressings.
Graphical abstract
Cui Cheng,Haowei Zhong,Yuan Zhang,Xiaoran Gao,Jianmin Wang,Jingfeng Liu,Xiao Han
Clinically, systemic antibiotic therapy and traditional dressings care are not satisfactory in treating chronic diabetic ulcers (DU). Therefore, we presented sprayable antibacterial hydrogel for effective treatment of DU by using antibacterial macromolecules (quaternized chitosan, QCS, Mn ≈ 1.5 × 10 5 ), photothermal antibacterial nanoparticles (ε-poly- l -lysine grafted graphene quantum dots, GQDs-ε-PL) and miocompatible macromolecules (benzaldehyde-terminated four-arm poly(ethylene glycol), 4 arm PEG-BA) as materials. The results revealed that the hydrogel could be in situ formed in 70–89 s through dynamic imine bonds crosslinking and exhibited a pH-dependent swelling ability and degradability. The hydrogel could respond to bacterial triggered acidic environment to play a synergistic effect of chemotherapy and xenon light irradiated PTT, leading to the rupture of the bacterial membrane and the inactivation of bacteria, promoting the migration and proliferation of fibroblast cell, enhancing the adhesion of platelet endothelial cell, and finally accelerating the healing of infected diabetic wound. Moreover, the hydrogel displayed self-healing, hemostatic, and biocompatible abilities, which could provide a better healing environment for wound and further promote wound healing. Hence, the multifunctional hydrogel is expected to be a potential dressing for the clinical treatment of DU.
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