Gelatin-Based Electrospun Nanofibers Varied in Morphologies with Poly(ethylene imine) and Poly(2-ethyl-2-oxazoline): Allantoin-Modified for Antimicrobial Skin Compatibility

This study focuses on developing and thoroughly assessing innovative, nontoxic, antibacterial, and skin-compatible electrospun nanofibrous mats-coated cotton composites. Materials were created by selectively incorporating different polyethylenimine polymers (PEI) and poly(2-ethyl-2-oxazoline)-based (P2Ox) polymers into a gelatin biopolymer matrix, which was then electrospun onto a cotton fabric substrate. Three distinct variants of PEI, such as branched PEI (BPEI), linear PEI (LPEI), and a P2Ox-based copolymer (P2Ox-co-PEI), were systematically integrated to fabricate hybrid, Janus, and core–shell electrospun structures, facilitating prominent change of their effects on the resultant material properties. Morphological investigation indicated that electrospun fibers in hybrid morphology have a smaller average diameter (200 nm) than core–shell counterparts (360 nm), although all produced mats demonstrated intrinsic hydrophilicity. The air permeability of the samples exhibited considerable variation between 41 and 1130 L/m²/s airflow rates. To enhance the biocompatibility and bioactivity of the nanofibrous mat surfaces, the materials were subjected to postprocessing by the chemical bonding of Allantoin (Alla). The antimicrobial effectiveness was also confirmed against Staphylococcus aureus (bacteria) and Candida albicans (Fungi) through the agar diffusion test, with the highest inhibitory impact at 18 and 20 mm, respectively. Notably, all electrospun mats, especially those modified with Alla, promoted L929 fibroblast proliferation, demonstrating superior biocompatibility. Finally, the biocompatibility of the Alla-modified samples was further investigated by a skin irritation test against human epidermal keratinocytes. The developed composites are biocompatible, nontoxic, and highly skin-compatible and have considerable potential for biomedical applications, such as wound dressings, drug delivery systems, and tissue engineering scaffolds.