A novel device for in-situ on-demand hydrogen sulfide generation and delivery to increase tissue perfusion to chronic wounds

There is significant evidence linking deficiency in endogenous hydrogen sulfide (H2S) to delayed healing of wounds. Systemic administration of H2S donors has been shown to markedly improve the healing rate of ischemic open wounds. This paper describes a novel H2S therapy approach, namely H2EALS™, as an exogenous supplement to accelerate healing. H2EALS™ employs a controllable process for in-situ conversion of a metal sulfide coating to H2S gas for safe and effective H2S treatment. The core technology topically releases a targeted quantity of H2S molecules within the dressing for absorption into the open wound using control and delivery protocol specified by the end-user. Benchtop studies have evaluated precision in the rate and amount of H2S released and the degree of control, all required for safe treatment. In preclinical studies using rodent and swine models, the potential widespread dispersion of the H2S delivered was evaluated with an H2S sensing approach, while the physiological dose-response in terms of absorption and perfusion within the wound and periwound regions were examined using both H2S measurement and Laser Speckle Contrast Imaging (LSCI). Benchtop studies on H2EALS™ demonstrate clinically relevant performance durability and control over H2S dose administered. With low power requirement, high dosage control, and relatively low dose-to-dose variability, electroactive H2S sources with capacity of > 2 µmol/application were fabricated to last beyond a typical 14-day wound treatment period. In-vivo studies on open wounds in Sprague-Dawley rats treated at 25 to 100 nmol/dose indicated rapid tissue absorption of H2S gas. Real-time breath- and skin-emitted H2S measured on swine revealed no evidence of widespread dispersion when up to 500 nmol/dose was delivered directly to an 8-mm open wound. Our results emphasize the need for informed delivery and absorption of H2S to the target tissue and we demonstrate the potential of the H2EALS™ technology of safe and effective H2S treatment of open wounds and in acceleration of wound healing. The results are a partial contribution to evaluating the impact of H2EALS™ on wound healing acceleration and tissue repair.