Comparisons of antibacterial performances between electrospun polymer@drug nanohybrids with drug-polymer nanocomposites

Blended electrospinning is frequently utilized to prepare drug-loaded nanocomposites to take advantages of the nanofibers’ small diameters and large surface area. However, the homogeneous distribution of drug makes most of them embedded in the polymeric matrix, which correspondingly limits the functional applications. In the present study, a modified coaxial electrospinning was implemented, in which a pure drug (ciprofloxacin, CIP) solution was explored as a sheath working fluid to coat drug on the surface of polymer (cellulose acetate, CA) nanofibers to form a polymer@drug nanohybrid (NH). For comparison, an electrospun CA-CIP nanocomposite was prepared using a one-fluid blending process. Both NCs and NHs had linear morphologies without beads or spindles on them. CIP were embedded on the surface of CA nanofibers in the NH as crystalline nanoparticles, whereas CIP co-existed with CA in the NCs in an amorphous state. In vitro dissolution tests verified that NHs release the surface CIP in a pulsatile manner and NCs release the loaded CIP in a continuously. Antibacterial tests demonstrated that the NHs with a drug loading of 3.9% (w/w) showed a better zone of inhibition zone for Staphylococcus aureus and Escherichia coli than the NCs with a drug loading of 16.7% (w/w). Thus, the present study pioneered the way for the development of novel nanohybrids with improved functional properties. Graphical abstract