Trilayered Self-Pumping Dressing with Micropore Array for Drug Backflow Release in Diabetic Wound Healing

Excessive exudate in chronic wounds increases the risk associated with tissue hydration, bacterial infection, and increased inflammation. While Janus dressings enable unidirectional exudate transport, current designs overlook the critical need for maintaining optimal wound humidity and providing on-demand antibacterial/anti-inflammatory treatment to support repair. To address this, a self-pumping trilayered dressing (GCSIP) is developed, integrating polyhexamethylene guanidine-grafted triglycidyl glycerol ether (PHMG-GTE)-modified cotton, ibuprofen-loaded silk fibroin (IBU/SF), and polyurethane (PU). This architecture achieves autonomous, unidirectional fluid transport and drug release via a controlled reflux mechanism triggered upon full saturation of the cotton layer. A precisely engineered microporous array (400 µm pores, 6 mm spacing) is used to optimize directional transport and reflux efficiency. Upon saturation, partial reflux through the array facilitates the release of dissolved SF molecules and 87.6% of the encapsulated ibuprofen (IBU) within 72 h. The released components significantly reduced TNF-α and IL-6 expression in M1 macrophages by 90.4% and 87.6%, respectively. The in vivo results demonstrate excellent biocompatibility and nearly complete wound healing within 15 days, with a residual wound area ratio of only 0.8%. This study establishes an on-demand exudate regulation and drug release mechanism for multifunctional dressings to accelerate wound recovery.