Activity of silver-zinc nanozeolite-based antibiofilm wound dressings in an in vitro biofilm model and comparison with commercial dressings

Abstract

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 to prevent infection in burn wounds. Presently, many commercial silver dressings 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 ions 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, 3.7, and 221 µg/cm². 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 (ATCC 4708) and methicillin-resistant Staphylococcus aureus (ATCC 33592). 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 wound dressings in a colony biofilm model. Nanozeolite-entrapped silver/zinc antimicrobials in association with quat have the potential for application in biofilm-infected wounds and require animal and clinical studies for definitive proof.

Graphical abstract