Evaluation of the anti-biofilm activities of bacterial cellulose-tannic acid-magnesium chloride composites using an in vitro multispecies biofilm model

Chronic wounds are a serious worldwide problem,which are often accompanied by wound infections.In this study,bacterial cellulose(BC)-based composites introduced with tannic acid(TA)and magnesium chloride(BC-TA-Mg)were fabricated for anti-biofilm activities.The prepared composites’surface properties,mechanical capacity,thermal stability,water absorption and retention property,releasing behavior,anti-biofilm activities and potential cytotoxicity were tested.Results showed that TA and MgCl_(2) particles closely adhered to the nanofibers of BC membranes,thus increasing surface roughness and hydrophobicity of the membranes.While the introduction of TA and MgCl_(2) did not influence the transparency of the membranes,making it beneficial for wound inspection.BC-TA and BC-TA-Mg composites displayed increased tensile strength and elongation at break compared to pure BC.Moreover,BC-TA-Mg exhibited higher water absorption and retention capacity than BC and BC-TA,suitable for the absorption of wound exudates.BC-TA-Mg demonstrated controlled release of TA and good inhibitory effect on both singly cultured Staphylococcus aureus and Pseudomonas aeruginosa biofilm and co-cultured biofilm of S.aureus and P.aeruginosa.Furthermore,the cytotoxicity grade of BC-TA-6Mg membrane was eligible based on standard toxicity classifications.These indicated that BC-TA-Mg is potential to be used as wound dressings combating biofilms in chronic wounds.