Multi-hierarchical assemble nano-fibrous dressing for burn wound ultra-fast healing with dynamical exudate regulation, thermal management, and non-leaching sterilisation

Abstract

To endow the nano-fibrous wound dressing with moisture-absorption, moisture-retention, thermal-management and anti-bacterial performances, a multi-hierarchical assemble process including electro-micro-encapsulation, electro-interpenetration and electro-deposition was used to create a structural integration including core–shell structure, interpenetrated structure and in-situ coating. First, a phase-transition thermal-management electro-spun consisting of PVDF shell and n-hexadecane core was fabricated from the coaxial electro-spinning, the heat-absorbing effect from n-hexadecane melting offers a cool feeling to make burn wounds feel comfortable. Second, an interpenetration process between PVA electro-spun and PVDF@n-hexadecane core–shell electro-spun was carried out by a heterologous co-electro-spinning device. By regulating the area density and the continuity of the hydrophilic phase and hydrophobic phase as well, the moisture-absorption and the moisture-retention performances can be manipulated. Third, a nano-capsule consisting of PCL outer shell and dual-component anti-bacterial agents as core was obtained from coaxial electrospray and then was further electro-deposited on the surface of the obtained interpenetrated membrane. After the melting of the PCL outer shell, not only the in-situ immobilization of anti-bacterial particles on the membrane surface (non-leaching sterilisation) was carried out, but also the exposure of anti-bacterial components. Owing to the collaborative integration of multiple functional ingredients and various structural elements, this composite nano-fibrous dressing displays a good moisture-absorption performance for removing exudate, a desired moisture-retention performance for offering wet surrounding to promote tissue regeneration, a comfortable absorption-heat effect and an excellent anti-bacterial performance. Combined with cytotoxicity and animal experiment evaluations, this multi-functional dressing presents a quicker healing period for second-degree burn compared to existed commercial fibrous dressing.