Silver-loaded carboxymethyl cellulose nonwoven sheet with controlled counterions for infected wound healing

Carboxymethyl cellulose (CMC) is a promising material for moist wound healing, and silver loading onto CMC has been examined for anti-bacterial activity. In this study, we developed silver-loaded CMC nonwoven sheets with different counterions, namely sodium CMC (CMC-Na/Ag) and partially protonated CMC (CMC-H/Ag), to examine their anti-bacterial and wound-healing properties. Owing to the presence of counter protons, CMC-H/Ag showed slower water adsorption, dissolution, and Ag release than CMC-Na/Ag. In addition, CMC-H/Ag and CMC-Na/Ag exhibited differences in anti-bacterial activities in shake-flask and inhibition zone tests in vitro. An in vivo experiment using a pressure ulcer mouse model with Pseudomonas aeruginosa infection showed that CMC-Na/Ag significantly accelerated wound healing compared to CMC-H/Ag and a commercially available Ag-loaded CMC nonwoven sheet, Aquacel Ag. These results suggest the importance of controlling CMC counterions and the therapeutic potential of the developed product as a wound dressing.