“Monitor-and-treat” that integrates bacterio-therapeutics and bio-optics for infected wound management

Wound infections are one of the major threats to human health, accounting for millions of deaths annually. Real-time monitoring, accurate diagnosis, and on-demand therapy are crucial to minimizing complications and saving lives. Herein, we propose a "monitor-and-treat" strategy for infected wound management by integrating the emerging development of bacterio-therapeutics and bio-optics. The upper layer consists of gelatin methacryloyl (GelMA)-collagen III methacryloyl (Col₃MA) (GC), Reuterin (Reu) isolated from the probiotic <i>Lactobacillus reuteri</i> (L. reuteri) and microfluidic safflower polysaccharide (SPS)@GelMA microspheres using 3D printing technology. The lower layer is made of acryloylated glycine (ACG) hydrogel with tissue adhesion capability, which enables the hydrogel to adapt to the movement and stretching of the skin. By integrating temperature-sensitive polydimethylsiloxane (PDMS) optical fibers, the ACG-GC/Reu/SPS-PDMS hydrogel could accurately and steadily sense and send wound temperature information to intelligent devices for real-time monitoring of the healing status ("monitor"). The double-layered hydrogel not only inhibited bacterial survival and colonization (97.4 % against <i>E. coli</i> and 99 % against <i>S. aureus</i>), but also exhibited remarkable hemostatic properties. Furthermore, it was conducive to L929 cell proliferation and pro-angiogenesis, and promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype, therefore creating a favorable immune microenvironment at the wound site. Animal experiments using SD rats and Bama minipigs demonstrated that this hydrogel promoted wound closure, directed polarization to M2 macrophages, alleviated inflammation, enhanced neovascularization, therefore accelerating infected wound healing ("treat"). In addition, RNA-Seq analysis revealed the mechanism of action of ACG-GC/Reu/SPS-PDMS hydrogel in modulating key signaling pathways, including down-regulation of AMPK, IL-17, and NF-κB signaling pathways, activation of NLRP3 inflammatory vesicles, and enrichment of MAPK, TGF-β, PI3K-Akt, TNF, and VEGF signaling pathways. The modulation of these signaling pathways suggests that hydrogels play an important role in the molecular mechanisms that promote wound healing and tissue regeneration. Therefore, the design of this study provides an innovative and multifunctional bandage strategy that can significantly improve pathologic diagnosis and wound treatment.