Design of a silver-zinc nanozeolite-based antibiofilm wound dressing activity in an in vitro biofilm model

Background Infected wounds are a major health problem as infection can delay wound healing. Wound dressings play an important part in wound care by maintaining a suitable environment that promotes healing. Silver sulfadiazine dressings have been used for preventing infection in burn wounds. Presently, there are many commercial silver dressings that have obtained FDA clearance. Results In this study, we report on a novel silver dressing using microporous aluminosilicate zeolites, termed ABF-XenoMEM. Silver and zinc ion are encapsulated in the zeolite supercages. We show that the silver-zinc zeolite (AM30) alone is effective at inhibiting biofilm formation. The encapsulation protects the silver from rapidly precipitating in biological fluids. We exploit the negatively charged zeolite surface to associate positively charged quaternary ammonium ions (quat) with the zeolite. The combination of the AM30 with the quat enhances the antimicrobial activity. The colloidal nature of the zeolite materials makes it possible to make uniform deposits on a commercial extracellular matrix membrane to develop the final dressing (ABF-XenoMEM). The optimum loading of silver, zinc and quat on the dressing was found to be 30, 6 and 220 µg/cm ² . Using a colony biofilm model, the activity of ABF-XenoMEM is compared with four well-studied silver-based commercial dressings towards mature biofilms of Pseudomonas aeruginosa (PAO1) and methicillin-resistant Staphylococcus aureus (MRSA). Cytotoxicity of the dressings was examined in HepG2 cells using the MTT assay. Conclusion This study shows that the ABF-XenoMEM is competitive with extensively used commercial dressings and demonstrates using a colony biofilm model that nanozeolite-entrapped antimicrobials have potential for alleviating biofilm-infected wounds.