Development of an aligned nanofiber composite silk fibroin multilayer dressings: Accelerating wound healing and reducing scar formation.

This study developed a novel three-layer composite dressing to accelerate wound healing and reduce hypertrophic scar formation. The dressing features an asymmetric wettability structure fabricated by electrospinning and consists of a hydrophilic outer layer of freeze-dried absorbent cotton, a silk fibroin (SF) transitional layer, and a hydrophobic inner layer of aligned poly(lactic acid) (PLA) nanofibers loaded with retinoic acid (RA). The SF transitional layer plays a critical role by bridging the outer and inner layers, establishing a smooth wettability gradient that facilitates efficient unidirectional fluid transport from the wound surface to the outer absorbent layer. This design not only manages wound exudate to maintain a moist yet non-wet microenvironment but also enhances cell adhesion, proliferation, and directional migration. In vitro evaluations demonstrated improved liquid flow and robust cellular responses, while in vivo tests revealed accelerated wound closure and significantly reduced scar formation in both burn and hypertrophic scar models. Overall, integrating the SF transitional layer with aligned RA-loaded PLA nanofibers offers a promising strategy for advanced wound management and scar minimization.