A collagen wound dressing with silver ion exchanged zeolite based active ingredient and its comparison with commercial dressings

Introduction: Biofilm formation has been reported to cause chronic inflammation and delay healing of wounds, especially chronic and acute dermal wounds. Biofilms formed deep in the wound disrupts healing and is hard to eradicate (1). Current clinical treatment includes cleansing, debridement, refashion and dressing. Developing wound dressings that can destroy biofilms with minimum cytotoxicity is an active product development are. We will present data on a dressing which has a 1) collagen matrix that promotes the transition of the wound to a remodeled, healed state; 2) embedded within this matrix are porous nanozeolite crystals with positively charged surfactant molecules 3) these nanozeolite crystals also encapsulate antimicrobial silver ions (2). We will present data comparing the zeolite-dressing with four of the leading silver-based commercial dressings in their ability to reduce bacterial load of mature Pseudomonas aeruginosa (PA01) biofilms using in vitro colony biofilm assay.Methods:Wound dressings were prepared by deposition of silver-zinc ion-exchanged nanozeolites along with benzalkonium chloride on a commercially available ECM matrix. These dressings and the commercial dressings were introduced on top of a SWF (simulated wound fluid) layer on a 48-hour PA01 biofilm grown on a cellulose membrane resting on a nutrient-loaded agar gel. After well-defined periods of time (1-7 days), the bacteria on the dressing and the cellulose membrane were extracted and the bacterial colonies counted.Results:On the already formed biofilms, the zeolite-encapsulated silver-based nanozeolite dressing performed significantly better (p 0.05) than the commercial dressings in reducing the bacterial load. For days 1-4, there was no bacteria detected on the nanozeolite dressing or the cellulose membrane. The four commercial membranes all had residual bacteria on the dressing and the membrane.Discussion: The wound dressing in this study has well balanced efficacy against biofilm and minimized cytotoxicity. By protecting the silver ion inside of zeolite particles, silver participation and deactivation in SWF is minimized. Compared with the commercial dressings, less silver is used for improved efficacy against biofilms. We hypothesize that this advantage will translate to real infected wounds, thus requiring lower amounts of silver to maintain the antimicrobial efficacy as compared to commercial silver-dressings. We also hypothesize that lower amounts of silver will lead to lower cytotoxicity, and that the ECM dressing will promote wound healing. These hypotheses will be confirmed using an infected partial burn thickness porcine model before the poster presentation.References:1. Percival, S.L., Hill, K. E., Williams, D. W., Hooper, S. J., Thomas, D.W., Costerton, J.W., A review of the scientific evidence for biofilms in wounds, Wound Rep Reg 20, 647–657 (2012) 2. Guerrero-Arguero, I., Khan, S. R., Henry, B. M., Garcia-Vilanova, A., Chiem, K., Ye, C., Shrestha, S., Knight, D., Cristner, M., Hill, S., Waldman, W. J., Dutta, P. K., Torrelles, J. B., Martinez-Sobrido, L., & Nagy, A. M. (2023). Mitigation of SARS-CoV-2 by Using Transition Metal Nanozeolites and Quaternary Ammonium Compounds as Antiviral Agents in Suspensions and Soft Fabric Materials. International journal of nanomedicine, 18, 2307–2324 (2023) https://doi.org/10.2147/IJN.S396669 3. May A., Kopecki Z., Carney B., Cowin A., Antimicrobial silver dressings: a review of emerging issues for modern wound care, ANZ J Surg 92, 2022, 379–384, doi: 10.1111/ans.17382