Engineering quaternized chitosan in the 3D bacterial cellulose structure for antibacterial wound dressings

Balancing antibacterial properties with biocompatibility is of paramount importance for wound dressings loaded with antibacterial agents. In this work, a water soluble antibacterial agent, quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) with an appropriate degree of substitution was introduced into the bacterial cellulose (BC) network by adding it into the BC culture medium. Results indicated that the addition of HACC could affect the yield of BC, porous structure, thermal stability, water absorption and antibacterial properties. HBC-1 with a low content of HACC (13.65 ± 0.30%) cannot inhibit the biofilm formation of bacteria, while HBC-3 with a high content of HACC (62.05 ± 0.90%) has a low yield of BC and confused structure. HBC-2 with an optimum concentration of HACC (37.33 ± 0.80%) possessed a typical porous structure, acceptable thermal stability, good water absorption and favorable antibacterial properties against Staphylococcus aureus (S. aureus, ATCC 25923) and methicillin-resistant S. aureus (ATCC 43300). Most importantly, none of the HACC/BC films exhibited cytotoxicity to NIH3T3 cells. We believe that obtained HACC/BC films with favorable bactericidal properties and biocompatibility could be potential candidates for wound dressings in clinical applications.