Oxygen-Delivering Antimicrobial Janus Hydrogels for Wound Healing Applications

The extended hypoxic microenvironment and ongoing infection in chronic wounds are two interrelated factors that significantly impede the healing process. The presented study develops a multifunctional bilayer hydrogel wound dressing that addresses these issues by combining oxygen production, oxygen transport, and antibacterial properties within a 3D printed bilayer hydrogel system. The bilayer hydrogel system is constructed with an upper layer of alginate loaded with oxygen-releasing CaO₂ and a lower layer of antibacterial polymer integrated with perfluorocarbon-based oxygen-adsorbing and transporting nanoparticles (PMOF). In addition, the resultant scaffold demonstrates 3D printability and enhanced mechanical and degradation properties. Under hypoxic conditions, continuous oxygen release (5.5 mg/L O₂ over 5 days) is achieved. Correspondingly, the bilayer system shows strong antibacterial activity against Gram Positive S. aureus and modest antibacterial activity against Gram negative E. coli bacteria. Furthermore, in vitro cell experiments show enhanced healthy cell viability after 7 days of incubation under hypoxic conditions. Lipid peroxidation results suggested that the bilayer system may provide antibacterial efficacy while maintaining oxidative cellular compatibility. Consistent with these findings, results from the in vitro scratch assay indicate that the Ge-PMOF/Alg-CaO₂ scaffold promotes wound closure, achieving around 90% and 95% closure under normoxic and hypoxic conditions, respectively.