Sustainable Electrospun PCL Nanofibers Reinforced With Eggshell Membrane for Prolonged Cu (II) Complex Release and Bioactivity

Electrospun polymeric nanofibers offer versatile platforms for diffusion‐controlled drug delivery; however, achieving prolonged and tunable release remains a key challenge. Eggshell membrane (ESM) was incorporated as a natural release‐modifying additive into polycaprolactone (PCL) nanofibers containing a Cu(II) Schiff base complex via electrospinning. Scanning and transmission electron microscopy confirm homogeneous fiber morphology and uniform ESM and Cu(II) complex distribution, while energy‐dispersive X‐ray spectroscopy confirms Cu and trace Zn associated with ESM. Fourier‐transform infrared spectroscopy and X‐ray diffraction indicate structural compatibility between PCL and ESM without formation of additional crystalline phases. Increasing ESM content yields higher specific surface area and reduced water contact angle, reflecting enhanced surface roughness and wettability. Release studies demonstrate an approximately 72% reduction in cumulative Cu(II) release compared to ESM‐free PCL nanofibers. Korsmeyer–Peppas kinetic analysis confirms Fickian diffusion (n = 0.173), with ESM markedly reducing the effective diffusion coefficient through increased diffusional tortuosity and reversible Cu(II)–ESM coordination, without altering the fundamental transport mechanism. ESM‐containing nanofibers additionally exhibit improved antibacterial activity against both Gram‐positive and Gram‐negative bacteria and time‐dependent antioxidant activity reaching 35.2% after 24 h for fibers with 5 wt.% ESM. These findings establish ESM as an effective natural excipient for regulating diffusion‐controlled release in electrospun drug‐delivery systems.