Functional Mesostructured Electrospun Polymer Nonwovens with Supramolecular Nanofibers

Mesostructured Polymer and Glass Microfiber Nonwovens with Supramolecular 1,3,5-Benzenetrisamide Nanofibers for Air Filtration

Hierarchically mesostructured nonwovens with complex fiber morphologies are gaining more and more interest for filtration applications as the increased surface area offers improved filtration efficiencies for particulate matter. Several concepts are known to fabricate such complex fiber morphologies; however, the control over the morphology remains challenging. Here, we report on the preparation of mesostructured nonwovens decorated with defined supramolecular nanofibers by physical vapor deposition of a selected commercially available 1,3,5-benzenetrisamide (BTA). Using polymer nonwovens as a support, we show that with this solvent-free process, the supramolecular nanofiber length can be tuned from 5 to 20 μm depending on the evaporation time resembling a bottlebrush-like morphology on the mesoscale. Whereas the model polymer nonwoven is unsuitable to capture particulate matter, the mesostructured nonwovens show an increasingly improved filtration efficiency of up to 87% for 2.0 μm particles at a low pressure drop of 90 Pa. Since the selected BTA has a pronounced thermal stability, this also enables the preparation of more temperature-resistant mesostructured nonwovens using a glass microfiber nonwoven as a support. We show that the morphology as well as the filtration efficiency of the mesostructured glass fiber nonwoven is maintained even after heat treatment at 200 °C for 24 h. This cannot be realized with nonwovens based on commodity polymers and engineering plastics. These results prove the general applicability of vapor-deposited supramolecular nanofibers and broaden the application window for such mesostructured nonwovens in the field of filtration and separation toward more efficient, robust, and also selective filter media.

Dual-Drug-Loaded Core-Shell Electrospun Nanofiber Dressing for Deep Burns

The epidermis of a deep burn wound is entirely absent and the dermal tissue sustains significant damage, accompanied by a substantial amount of tissue exudate. Due to the excessively humid environment, the formation of a scab on the wound becomes challenging, leaving it highly vulnerable to external bacterial invasion. In this work, a core-shell dual-drug-loaded nanofiber dressing was prepared by electrospinning technology for the synergistic treatment of a deep burn. The shell layer consists of polycaprolactone and chitosan encapsulating asiaticoside, with the core layer comprising the clathrate of 2-hydroxypropyl-β-cyclodextrin and curcumin. Upon application to the wound, the dual-drug-loaded nanofiber dressing exhibited rapid release of asiaticoside, stimulating collagen deposition and promoting tissue repair. The core-shell structure and clathrate configuration ensured sustained release of curcumin, providing antibacterial and anti-inflammatory functions for the wound. The mechanical strength, broad-spectrum antibacterial ability, cell proliferation, and adhesion ability of the nanofiber dressing showed its potential as a medical dressing. This dressing also exhibited excellent wound healing promoting effects in the SD rat burn model. This paper provides a strategy for burn wound healing.