Stabilization and controlled release of micro-encapsulated hydrogen peroxide for wound treatment applications

Hydrogen peroxide (H₂ O₂ ) disinfection applications are limited by its rapid inactivation. The aims of this study were to (i) micro-encapsulate H₂ O₂ in silica hydrogels to obtain controlled release up to 72 h, (ii) test hydrogel antimicrobial activity against four common pathogens and (iii) assess H₂ O₂ release kinetics and antimicrobial activity in 35-65% relative humidity and 37°C to approximate bandaged wound conditions.

Hydrogels were characterized using scanning electron microscopy, nitrogen sorption porosimetry, Brunauer Emmet Teller analysis and the Barret-Joyner-Halenda method. Hydrogels formed at lower pH demonstrated increased surface area and decreased pore size, resulting in H₂ O₂ release lasting 72 h. Using agar well diffusion for antimicrobial activity, statistically significant zones of inhibition (as compared to controls) were seen for Escherichia coli, Staphylococcus aureus, Pseudomona aeruginiosa and Vancomycin-resistant Enterococcus faecalis. Activity remained for hydrogels aged for 72 h in humid, 37°C conditions.

Hydrogels can be synthesized to provide a continuous, controlled release of H₂ O₂ for up to 72 h.

Stable, controlled-release H₂ O₂ hydrogels have potential applications for wound treatment and disinfection of medical equipment, through bonding to bandages or materials such as catheter lumens.