Coaxial PCL/Gelatin Nanofibers Integrated with Chitosan Hydrogel for Controlled Drug Delivery and Antibacterial Applications

A multifunctional bilayer nanofiber–hydrogel composite was developed to achieve controlled drug delivery with enhanced antibacterial performance. Coaxial electrospun poly(ε-caprolactone) (PCL)/gelatin nanofibers were integrated with a chitosan hydrogel layer for the delivery of Delafloxacin. The core–shell nanofiber structure enabled sequential drug release, where the gelatin shell promoted initial diffusion and the PCL core provided sustained release. The chitosan hydrogel acted as a diffusion-regulating barrier while contributing intrinsic antibacterial activity. Structural and physicochemical properties were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Mechanical strength and moisture management behavior confirmed suitable integrity and fluid handling capability. The composite exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli , with inhibition zones of approximately 51 mm and 35 mm, respectively. A sustained drug release of 73% over 120 h demonstrated effective release control compared to non-hydrogel scaffolds. Cytotoxicity results indicated high cell viability (>93%), confirming good biocompatibility. Overall, the hierarchical nanofiber–hydrogel design provides an effective platform for controlled drug delivery and antibacterial applications in advanced biomaterials.