Investigation of the effect of superabsorbent wound dressings with passive antimicrobial mechanism on release of bacterial endotoxins and binding of bacterial endotoxins in vitro

Background Chronic wounds are often delayed in healing due to bacterial colonization and associated inflammation. Rising antimicrobial resistance highlights the need for alternative treatment options like superabsorbent polymer (SAP)-based dressings, which absorb bacteria and endotoxins without inducing bacterial death or resistance. This study evaluates their potential to inhibit microbial growth, reduce biofilms, and minimize endotoxin release. Methods Five wound dressings, including SAP-based dressings, were tested for antimicrobial activity according to JIS L 1902. Reduction of an experimental E. coli biofilm was assessed through bacterial respiratory activity after 24 h of incubation with the dressings. Bacterial binding to different dressing layers was visualized using MTT staining and quantified via absorbance measurements. Additionally, endotoxin release during incubation with planktonic and biofilm E. coli and the binding of endotoxins from P. aeruginosa and E. coli were analyzed through absorbance-based methods after 24 h of incubation. Results All wound dressings exhibited significant or strong antimicrobial activity against E. coli and strong activity against P. aeruginosa . E. coli biofilm biomass was significantly reduced post-treatment. Bacterial binding tests indicated living bacteria primarily on wound contact layers, with fewer bacteria detected on active carbon and SAP layers. Endotoxin release after treatment with planktonic or biofilm E. coli bacteria was minimal. Conclusion In vitro findings suggest that passive antimicrobial wound dressings are promising alternatives to medicated versions, effectively reducing bacterial load and endotoxin release without promoting resistance. Further clinical studies are essential to confirm these results and assess differences among dressings in real-world healthcare settings.