Antibacterial Performance of PCL-Chitosan Core–Shell Scaffolds

In this study, antibacterial performance of the coaxially electrospun Poly-ε-caprolactone (PCL)-chitosan core–shell scaffolds developed, optimized and identified physically and chemically in our previous study, were evaluated for the suitability in wound healing applications. The aim of utilizing a core–shell fibrous scaffold with PCL as core and chitosan as shell was to combine natural biocompatibility, biodegradability and antibacterial properties of chitosan with mechanical properties and resistance to enzymatic degradation of PCL. The scaffolds were prepared with the optimized parameters, obtained from our previous study. Thickness and contact angle measurements as well as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses confirmed repeated fabrication of PCL-chitosan core–shell scaffolds. In this study, assays specific to wound dressing materials, such as water vapor transmission rate (WVTR), in vitro degradability and antibacterial tests were carried out. WVTR value of PCL-chitosan core–shell scaffolds was higher (2315 ± 3.4 g/m² · day) compared to single PCL scaffolds (1654 ± 3.2 g/m² · day) due to the higher inter-fiber pore size. Additionally, in vitro degradability assays showed that the susceptibility of chitosan to enzymatic degradation can be significantly improved by hybridization with more resistant PCL while still keeping the scaffold to be considered as biodegradable. Finally, inhibition ratio and inhibition zone measurements showed that the PCL-chitosan core–shell polymeric scaffolds had significant antibacterial performance (52.860 ± 2.298% and 49.333 ± 0.719% inhibition ratios; 13.975 ± 0.124 mm and 12.117 ± 0.133 mm clear inhibition zones, against E. coli and S. aureus, respectively), close to the native chitosan. Therefore, the developed scaffolds can be considered as suitable candidates for biodegradable wound dressing applications.