Fabrication and characterization of core–shell TiO2-containing nanofibers of PCL-zein by coaxial electrospinning method as an erythromycin drug carrier

As a novel transdermal delivery system, core–shell nanofibers exhibit a more controlled drug release than mono-structure nanofibers, especially when the hydrophilicity of core and shell polymers is different. Thus, this study aimed to produce biocompatible and antimicrobial erythromycin-loaded poly(caprolactone) (PCL/erythromycin) core with a zein-containing titanium dioxide (zein/TiO2) shell nanofibers. Accordingly, a specified concentration of PCL solution containing erythromycin and zein solution with titanium dioxide nanoparticle was prepared. Then, core–shell nanofibers were fabricated using co-axial electrospinning equipped with nozzles with different inner and outer diameters. The obtained morphology and diameter of core–shell nanofibers were characterized by scanning electron microscope (SEM) and were compared with the SEM images of PCL nanofibers, PCL/erythromycin nanofibers, zein nanofibers, zein/TiO2 nanofibers and PCL@zein core–shell nanofibers. The SEM images of PCL/erythromycin@zein/TiO2 nanofibers show that core–shell nanofibers are clearly fine, narrow, uniform and smooth without any adhesion with an average diameter of 625 nm. The core–shell structure of PCL@zein and PCL/erythromycin@zein/TiO2 nanofibers were confirmed by transmission electron microscope. The structure of nanofibers was approved by Fourier transform infrared and X-ray diffraction, showing the presence of PCL, zein, erythromycin and titanium dioxide in the obtained nanofibers. Moreover, UV–Vis spectroscopy was used to determine the in vitro drug release profile of erythromycin from prepared core–shell nanofibers, indicating the slow-release profile of the drug in 72 h. The antimicrobial properties of the core–shell nanofibers were considered by the zone of inhibition against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella bacteria. The results showed that core–shell nanofibrous mats possess excellent antimicrobial activities.