Fabrication of water-resistant, thermally stable, and antibacterial fibers through in situ multivalent crosslinking

Fibers are emerging materials for biomedical applications, including drug delivery, sensing, tissue engineering, and wound dressing. However, fibers produced from water-soluble polymers usually lose their morphology and quickly dissolve after exposure to water. Here, we developed a combined strategy of using multivalent crosslinkers along with in situ crosslinking to synthesize water-resistant and thermally stable hybrid fibers. In our design, polyvinyl alcohol (PVA), aldehyde-modified polyxylitol sebacate-co-polyethylene glycol (Ald_PXS-co-PEG, APP), and neomycin (Neo) were mixed to fabricate hybrid fibers through electrospinning. Several crosslinking chemistries were occurred in the hybrid fibers of PVA/APP/Neo, including the acetal bonds between PVA and APP, imine bonds between APP and Neo, and hydrogen bonds between PVA, APP, and Neo. These multiple chemical bonds allowed the PVA/APP/Neo fibers to maintain their fiber morphology after the immersion in the PBS solution, preserving the advantages of fibers (e.g., large surface-to-volume ratio and porosity) for applications in aqueous media. Particularly, the presence of Neo also provided the hybrid fibers with antimicrobial ability. Taken together, the in situ multivalent crosslinking has been demonstrated as a promising strategy to prepare stable and functional fibers for advanced applications.