Multifunctional chitosan cryogel bandages via column-flow synthesis for simultaneous hemostasis and anti-biofilm therapy.

Bacterial infection and hemorrhage remain significant clinical challenges for chronic wounds, despite advancements in antimicrobial strategies and materials. Herein, 980 nm-laser-responsive photothermal conjugated polymers (CPs) are combined with chitosan-based cryogels (CP@Gel) to achieve rapid hemostasis and efficient anti-infectious performance. CP nanoparticles (CP NPs) were prepared by nanoprecipitation and immobilized into cryogels via a novel column-flow-through method, resulting in high nanoparticle loading capacity and enhanced photothermal effects. The chitosan-based cryogels demonstrated quick blood absorption and rapid hemostatic abilities. Under near-infrared (NIR) exposure, the photothermal effect of CP@Gel induced bacterial membrane disruption and cytoplasmic leakage, nearly eliminating Methicillin-resistant Staphylococcus aureus (MRSA) within 5 min. Moreover, CP@Gel under NIR laser irradiation effectively destroyed mature MRSA biofilms and affected related biofilm-formation genes. Meanwhile, CP@Gel/NIR promoted MRSA-induced wound healing by controlling inflammatory responses, angiogenesis, collagen deposition, and affecting the expression of genes associated with inflammation and immune response. This work provides a promising approach for chronic wound healing by addressing both hemorrhage and MRSA contamination.