Poster O2 - Application of an Antimicrobial Nitric Oxide (NO) Releasing Wound Dressing Combined with a Rapid Blood Clotting Agent

Introduction: About 1 in 38 adults suffer from chronic wounds per year, making wound care management prominent in healthcare practices. More than $28.1 billion is spent on wound management to provide proper care for injuries, post-surgery treatments, and immediate care [1]. If wounds are not treated properly in a timely manner, they can result in chronic infections or impaired tissues leading to serious medical complications. Wound healing is a complex process and is mediated by numerous factors responsible for the regeneration and reorganization of the damaged tissue to its normal structure. Various types of wound dressings including adhesive bandages, antimicrobial dressings, and bioactive dressings have evolved throughout history to facilitate faster wound healing. Wound healing initially depends heavily on the rate of platelet aggregation and blood clot formation to prevent blood loss. Dressings are uniquely developed with synthetic or natural polymers and are loaded with various agents to target specific needs and control exudate, prevent infection, and promote the regeneration of tissues. Nytricx work focuses on developing a wound dressing that combines nitric-oxide (NO) anti-microbial with an anti-fibrinolytic agent to create a synergistic impact in prevention of infection and facilitation of wound healing. A nitric oxide donor (SNAP) and an antifibrinolytic agent, (TXA), are incorporated into the novel wound dressing to prevent infection and promote blood clot formation, respectively. The capabilities of the dressing are assessed by the release rates of both nitric oxide and TXA from the dressings.

Materials and

Methods: The wound dressing films are fabricated in a two-layer casting method. The first layer consists of 5-10 wt% Tranexamic acid (TXA) and 2.5 wt% Propolis in a PDMS (polydimethylsiloxane/silicone)-Tetrahydrofuran (THF) solution. The solution is cast into a Teflon mold, dried in the fume hood for 48 hours, and placed in a vacuum desiccator for 4 hours. The second layer consists of 10 wt% SNAP in a PDMS-THF solution and is cast on top of the first layer. The films are then dried under the fume hood for 48 hours. The release kinetics of the resulting TXA-Propolis-SNAP (TPS) films are then analyzed. NO release of the films is determined by incubating the films in a PBS/EDTA solution at 37°C and measuring the NO release by a chemiluminescence Nitric Oxide Analyzer 280i (Zysense, Frederick, CO). The antimicrobial activity of the films is assessed by exposing the films to bacterial strains (P. aeruginosa and MRSA) for 24 hours and counting bacterial colonies remaining compared to control. Additionally, the films are exposed to cell cultures to assess the cell cytocompatibility of the films. TXA release of the films is determined by Liquid Chromatography and Mass Spectrometry (LCMS). The films are exposed to blood to observe the blood clotting activity of the TXA released from the film. Blood clot formation is observed using SEM imaging.

Results, Conclusions, and Discussions: SNAP-loaded PDMS films released NO at physiological levels 2-4*10^(-10) mol*cm^(-2)* 〖min〗^(-1) over a period of 3 days. There was no significant leaching of SNAP from the PDMS. TXA release prevents endogenous fibrinolytic activity and thus promotes formation of a blood clot at the wound site. The synergistic effect of TXA with NO is expected to prevent blood loss, promote healing, and prevent infection and inflammation.

TXA-Propolis-SNAP incorporated PDMS films reduce bacterial growth in addition to facilitating blood clot formation. This study highlights the importance of the combination of two active components, NO and TXA, to facilitate the wound healing process. The findings of the study demonstrate how NO and TXA work together to promote blood clotting and prevent microbial infection and thus enhance overall wound healing.

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