Highly antibacterial electrospun double-layer mats for preventing secondary wound damage and promoting unidirectional water conduction in wound dressings

Abstract

The efficient absorption of wound exudate and the prevention of soft tissue infection are major concerns in wound repair. Good antibacterial agents and unique wound dressing structures can effectively reduce wound infection, thereby accelerating wound healing. In some double-layer asymmetric wound dressings, antimicrobial agents are incorporated in the hydrophilic layer, and only a small fraction of the antimicrobial agent penetrates the hydrophobic fibre layer towards the interior of the wound. Therefore, in this study, we chose curcumin (Cur.)/cellulose acetate (CA) as the hydrophobic inner layer. Not only does this effectively allow Cur. to make contact with the lining of the wound but it also prevents the wound from sticking. However, the mechanical properties of a single CA/Cur. layer are not ideal. Using polyacrylonitrile as the outer hydrophilic substrate improves the fibre mat mechanical properties. In addition, to further improve the hydrophilicity, the water contact angle was reduced by introducing a hydrophilic group (2-hydroxypropyl-β-cyclodextrin, β-CD) and changing the fibre roughness (nano-TiO2). Thus, wound dressings with high biocompatibility, excellent antibacterial properties, and unidirectional water conduction were constructed for preventing secondary wound damage. In terms of performance, it took 40 minutes for water to enter the hydrophilic fibre layer from the hydrophobic fibre layer (the water contact angle decreased from 121.24° to 85.42°), and it took 25 minutes for water to completely enter the fibre mats (the water contact angle decreased from 85.42°-0°), which is effective for draining wound exudate. In terms of antibacterial properties, the antibacterial rates of Cur. (8 wt%) against Escherichia coli and Staphylococcus aureus were 82.4% and 92.57%, respectively. The Cur./CA@PAN/β-CD/TiO2 bilayer asymmetric nanofibrous mats mimic the semipermeability of the extracellular matrix (ECM) and have high biocompatibility, which is effective for preventing secondary wound damage. It can be used as a low-cost, high-performance wound dressing with medical material potential.