Coaxial PCL-Core/PVA–Silk Fibroin-Shell Nanofibers for Sustained Ciprofloxacin Delivery and Antibacterial Activity: Direct Loading versus Chitosan Nanoparticle-Mediated Delivery

This study developed coaxial poly(ε-caprolactone) (PCL)-core/poly (vinyl alcohol)–silk fibroin (PVA/SF)-shell nanofibers to compare two strategies for delivering ciprofloxacin (CIP): direct loading versus chitosan nanoparticle-encapsulation. Key findings showed that nanoparticle integration produced finer, more uniform fibers (diameter reduced to 178 nm) and improved the material properties. These changes included improved moisture management (OMMC increased to 0.82), enhanced antibacterial activity (40 mm zone against E. coli), better thermal stability (degradation onset at 350°C), and increased tensile strength (2.18 MPa). The drug release profile was improved: while direct loading caused a rapid burst (85% in 10 h), the nanoparticle-mediated system showed a more sustained release pattern (94% over 70 h), while maintaining high cell viability (>90%). The work suggests that incorporating chitosan nanoparticles into a coaxial nanofiber structure may be a useful strategy for achieving sustained antibiotic delivery.