Electrospun Janus nanofibers loaded with a drug and inorganic nanoparticles as an effective antibacterial wound dressing.

The most important property of a wound dressing is its anti-bacteria performance. Although electrospun nanofibers are frequently demonstrated to be potent candidates as wound dressings, no Janus fibers have been explored for this popular application. In this study, a Janus wound dressing composed of polyvinylpyrrolidone (PVP) and ethyl cellulose (EC) polymer matrices was prepared via a side-by-side electrospinning process, in which ciprofloxacin (CIP) and silver nanoparticles (AgNPs) were loaded in the two sides. A homemade acentric spinneret was exploited to maintain a continuous preparation process. Scanning and transmission electron microscope results demonstrated that the Janus fibers had a uniform and cylindrical morphology with a clear Janus structure, and AgNPs distributed in one side. X-ray diffraction patterns suggested that drug was present in the fibers in an amorphous state owing to rapid drying and its good compatibility with PVP, which was verified by infrared spectroscopy. In vitro tests showed that over 90% of CIP was released within the first 30 min, ensuring a strong antibacterial effect at the initial stages of wound healing. The Janus fibers were demonstrated to have good bactericidal activity against the growth of both Gram-positive S. aureus and Gram-negative E. coli. The PVP-CIP/EC-AgNPs Janus fibers could thus be a promising candidate for effective wound dressings. This work paves a new way for creating Janus structure-based advanced functional nanomaterials.