Interaction and effectiveness of antimicrobials along with healing-promoting agents in a novel biocellulose wound dressing

An ideal wound dressing should keep the wound moist, allow oxygen permeation, adsorb wound exudate, accelerate re-epithelialization for wound closure, reduce pain and healing time, and prevent infection. Our novel biocellulose-based wound dressing was composed of three components: 1) biocellulose (BC), intended to create a moist and oxygen-permeated environment with exudate adsorption; 2) silk sericin (SS) known for its enhancement of collagen type I production, which is critical for re-epithelialization; and 3) the antiseptic polyhexamethylene biguanide (PHMB). To deliver an effective BC wound dressing, the interactions between the components (PHMB vs. SS) needed to be thoroughly analyzed. In this study, we investigated important parameters such as the loading sequence, loading concentration, and loading amount of the active compounds to ensure that the BC wound dressing could provide both antimicrobial activity and promote collagen production during healing. The loading sequence of SS and PHMB into BC was critical to maintain PHMB antimicrobial activity; silk sericin needed to be loaded before PHMB to avoid any negative impacts. The minimum PHMB concentration was 0.3% w/v for effective elimination of all tested bacteria (Bacillus subtilis, Staphylococcus aureus, methicillin-resistant S. aureus, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa). The amounts of SS and PHMB in BC were optimized to ensure that the dressings released the optimal amounts of both SS to enhance fibroblast collagen production and PHMB for effective antimicrobial activity.