Thermoresponsive Poly (N-Isopropylacrylamide)/Polycaprolacton Nanofibrous Scaffolds for Controlled Release of Antibiotics

Abstract

Smart antibacterial materials capable of releasing antibiotic drugs upon exposure to external triggers are highly desired for various medical applications. Herein, the fabrication of thermosensitive drug-loaded core−shell nanofibers using the electrospinning technique combined with in situ UV photopolymerization is reported on. The electrospinning method is used for shaping the core structure comprising biodegradable polymer polycaprolactone (PCL). The PCL fibers are coated with the temperature-responsive poly-N-isopropylacrylamide (PNIPAM) via a UV photopolymerization process that allows to precisely control the shell thickness as verified by transmission electron microscope (TEM) analysis. The temperature-dependent switchable wettability of prepared core−shell fibers is investigated and visualized though water contact angle measurements below and above the lower critical solution temperature. Loading of the antibiotic drug doxycycline hyclate (Doxy) in the PCL core nanofibers results in drug-encapsulating fiber meshes that allow diffusion of drug molecules through the PNIPAM shell in a temperature-dependent manner. The antibacterial activity is examined using Gram-negative Escherichia coli (E. coli) as well as Gram-positive Staphylococcus aureus (S. aureus) bacteria. The results demonstrate the high suitability of prepared biocompatible electrospun core−shell PCL/PNIPAM nanofibers as carriers for antibiotic drugs with temperature-sensitive release behavior.