Hydrogels for Local and Sustained Delivery of Bacteriophages to Treat Wound Infections.

Bacteriophages (phages) are viruses that specifically target and kill bacteria, serving as a promising therapeutic to combat multidrug-resistant (MDR) pathogens such as Pseudomonas aeruginosa ( Pa ). However, delivering adequate concentrations of active phages directly to the infection site over sufficient times to eradicate infections remains an outstanding challenge to phage therapy (PT). Here we present "HydroPhage", a biocompatible hydrogel system for the sustained release of high-titre phages to effectively treat infections caused by MDR pathogens. We develop injectable hydrogels comprised of hyaluronic acid (HA) and polyethylene glycol (PEG) crosslinked through static covalent thioether bonds and hemithioacetal-based dynamic covalent crosslinks (DCC), which encapsulate phages at concentration up to 10 11 PFU per mL gel, and achieve sustained release over a week with more than 60% total phage recovery. In a preclinical mouse model of extended wound infection, we demonstrate enhanced bacterial clearance compared to intravenous treatment. Thus, using hydrogels for local and sustained delivery of phage may represent an effective approach to eradicating MDR infections broadly.