Bacteriophage and Nitric Oxide Combined Release from a Dual Hydrogel Matrix for Wound Healing Applications.

Infection sites and open wounds provide a prime environment for the growth of opportunistic pathogens, leading to persistent infections caused by bacteria that contain antimicrobial-resistant phenotypes. Mistreatment of these wound infections often increases antimicrobial resistance (AMR), thereby decreasing the effectiveness of antibiotics. With the increase in AMR, new antimicrobial therapeutics that target these hard-to-kill pathogens are needed. Herein, naturally harvested bacteriophages (ECΦ) were combined with another established antimicrobial molecule, nitric oxide (NO). This combination has rarely been explored in biomedical devices but shows excellent potential for developing broad-spectrum, antibacterial materials. Bacteriophages were encapsulated in alginate microbeads and suspended in a NO-releasing thermoresponsive hydrogel. The phages were shown to have a delayed release from the alginate beads when incorporated into the gel, compared to the release observed within 24 h in aqueous medium. This delayed release enabled tunable phage delivery by adjusting the viscosity of the bulk gel base. Additionally, we used alginate as the base for microbeads, resulting in a physiologically safe material due to its proven biocompatibility. The final ECΦ and NO-releasing bead-gel matrix demonstrated 5-10 times larger zones of bacterial killing while maintaining low cytotoxicity, enabling further development in various clinical applications, including wound healing.