Lysozyme-based nanozyme encapsulated in double-network hydrogel for monitoring and repair of MRSA infected wounds

The presence of bacterial infection at the wound site poses a huge socioeconomic burden to public health as it adversely affects the tissue regeneration and thereby prolongs the wound healing process. To overcome the "black-box" status of healing process, the effective monitoring and treatment of infected wound is imperative in clinical practice, which has urged continuous exploration of wound dressings with integrated abilities of antibacterial effect, timely diagnosis and therapy. In this study, a dual-functional hydrogel of antimicrobial and the ability to monitor wound infections was prepared. In the gel, antibacterial protein of lysozyme was used for the sufficient loading of hemin molecules. The obtained lysozyme@Hemin nanopaticles (Ly@He NPs) was co-encapsulated with AgNO3 in the double-network hydrogel composed of gelatin and polyvinyl alcohol, which endows the obtained hydrogel not only desirable mechanical characteristics but dual capabilities of bactericidal effect and bacterial infection monitoring around the wound site. In addition to the sustained bactericidal effects by the silver leveraging from the hydrogel, the generation of abundant reactive hydroxyl radicals induced by the nanozyme of Ly@He NPs contributed significantly to the improved antibacterial activity of hydrogel. Moreover, based on the peroxidase (POD)-like activity, the prepared hydrogel was capable of monitoring the wound infection status by the colorimetric detection of glutathione, a biomarker of bacterial infection. Finally, both in vivo and in vitro experimental results pointed to the satisfying efficacy of the hydrogel to eliminate and monitor bacterial infection. Therefore, the proposed system holds enormous potentials in the development of integrated nanoplatforms for the diagnosis and on-demand treatment of bacteria-infected wounds.