Preparation and characterization of unidirectional water-transported bilayer PLA/ZnO-PAN/SPA nanofibrous membrane for wound healing

Wound infection caused by excessive exudate leads to overhydration of wounds and prevents wound healing. Thus, there is a need for a wound dressing to be developed that can unidirectionally export excess biological fluid while inhibiting bacterial infection. Herein, a nanofibrous bilayer membrane with a unidirectional water transport function was fabricated by electrospinning as a novel wound dressing, which can export excess biological fluid efficiently and further inhibit bacterial infection. The inner layer of the bilayer nanofiber membrane is polylactic acid (PLA)-zinc oxide (ZnO) nanofibers, which are hydrophobic and antibacterial. The outer layer is polyacrylonitrile (PAN)-sodium polyacrylate (SPA) nanofibers, which are hydrophilic and liquid-absorbent. The bilayer nanofibrous membrane's morphology, mechanics, thermal stability, wettability, water absorption, gas permeability, and unidirectional water transport ability were characterized and evaluated. The study showed that the nanofibrous bilayer membrane exhibited excellent physicochemical properties and biological performance, and its mechanical properties can reach 4.6 MPa. In addition, when the thickness of the hydrophobic layer is 3 µm and the thickness of the hydrophilic layer is 44 µm, the double-layer fiber membrane can effectively export the excess biological fluid in 5.09 s and prevent the wound from wetting again. The nanofibrous bilayer membrane with excellent water absorption, air permeability, thermal stability, and mechanical strength provides a feasible solution for chronic wound healing.