Facile Synthesis of Thermo-Sensitive Composite Hydrogel with Well Dispersed Ag Nanoparticles for Application in Superior Antibacterial Infections

In this study, we have described a facile process for fabrication of multifunctional composite hydrogel, in which sodium alginate was subjected to cross-linking using Ca2+ derived from ZnO/CaCO3/Ag composite nanospheres. The ZnO/CaCO3/Ag composite nanospheres were prepared based on our previously reported AA-[Zn(OH)(4)](2-) composite nanosphere reaction conducted with silver and calcium salt following hydrothermal method, that led to the disintegration and release of Ca2+ under acidic conditions for application as a cross-linking agent to catalyze reaction with sodium alginate. Ag nanoparticles were well-dispersed in the multifunctional composite hydrogel, exhibiting excellent antibacterial activity. Additionally, polydopamine (PDA) with photothermal effect was also added to obtain a multifunctional composite hydrogel, and this hydrogel showed photothermal conversion performance and facilitated the release of Ag+ to achieve the rapid antibacterial effect. Simultaneously, PDA NPs could scavenge free radicals and improve cell adhesion. All such features would promote wound healing. The potent antimicrobial activity of the prepared composite hydrogel was demonstrated in the mouse model of S. aureus infection, and biosafety of the hydrogel was confirmed by conducting histopathological examination in the mouse model. This type of multifunctional hydrogel wound dressing with photosensitive and antibacterial properties presents with broad applications and prospects in antibacterial treatment.