Conventional food packaging materials often suffer from limited antimicrobial/antioxidant activity, driving demand for multifunctional biopolymer-based alternatives. Herein, chitosan thiourea (CST) was synthesized and characterized through FTIR and elemental analyses. It was then blended with poly(ethylene oxide) (PEO) and functionalized with berberine (BBR) and Ti₃C₂Tₓ MXene (MXene) nanosheets via electrospinning to fabricate active nanofibers (NFs) for strawberry preservation. The composite NFs were comprehensively characterized in terms of morphology, structural interactions, thermal stability, surface wettability, swelling behavior, water vapor permeability (WVP), antioxidant activity, antimicrobial efficacy, and BBR release kinetics. The optimized PEO9,70/CST2,30/BBR5/MXene5 NFs displayed a uniform, bead-free morphology with an average diameter of ~300 nm. MXene incorporation markedly reduced swelling and WVP, while improving thermal stability. The incorporation of BBR significantly enhanced the antioxidant and antimicrobial properties of the NFs. BBR release followed a Fickian diffusion-controlled Korsmeyer–Peppas model, reaching 62.5% after 48 h, which was comparable to the 65.8% release observed from PEO9,70/CST2,30/BBR5 NFs. Over 5 days of storage at room temperature, PEO9,70/CST2,30/BBR5/MXene5 NFs most effectively preserved strawberry quality, limiting weight loss to 18% (versus 39% for unwrapped fruit), maintaining firmness at 1167 mg, total soluble solids at 8.5 °Brix, total phenolic content at 1.5 mg gallic acid/g, and titratable acidity at 0.7 g citric acid/100 g, while delaying visible microbial spoilage. Overall, the developed PEO/CST/BBR/MXene electrospun NFs showed strong potential as active packaging materials designed to preserve quality and prolong the storage stability and shelf life of strawberries, which are highly perishable fruits.
