Application of multilayer drug-loaded hydrogels in protection of open abdomen wounds

Open abdomen (OA) therapy is crucial for managing severe abdominal infections, intra-abdominal hypertension, and trauma but often faces complications like infections and enteric fistulas. To address this, a novel multilayer drug-loaded hydrogel dressing was designed to promote wound healing. The dressing comprises a bottom layer of a carboxymethyl chitosan/aldehyde-modified hyaluronic acid (CC/HA-CHO) hydrogel loaded with Ag nanoparticles (AgNPs) for rapid gelation and broad-spectrum antibacterial action; a middle polyacrylamide (PAAm) gel layer loaded with interleukin-4 (IL-4) to polarize macrophages toward the M2 phenotype for tissue repair; and a top polydimethylsiloxane (PDMS) antifouling layer treated with oxygen plasma for enhanced adhesion and hydrophilicity. Characterization via FTIR, SEM, swelling tests, and drug release assays confirmed the hydrogel's structure, stability, and sequential release of AgNPs and IL-4. In vivo experimental results show that the percentage of wound closure in the drug-loaded hydrogel group reached approximately 30% on day 7, while that in the control group was only about 10%. Thus, the drug-loaded hydrogel can significantly accelerate wound healing of open abdominal wounds. This multifunctional hydrogel combines antibacterial, anti-inflammatory, and tissue-regenerative properties, offering a promising strategy for OA wound management.