Study of smart antibacterial PCL-xFe₃ O₄ thin films using mouse NIH-3T3 fibroblast cells in vitro

Surface energy plays a major role in prokaryotic and eukaryotic cell interactions with biomedical devices. In the present study, poly(ε-caprolactone)-xFe₃ O₄ nanoparticles (PCL-xFO NPs; x = 0, 10, 20, 30, 40, 60 wt% FO concentration in PCL) composite thin films were developed for skin tissue regeneration. The surface properties in terms of roughness, surface energy, wettability of the thin films were altered with the incorporation of Fe₃ O₄ NPs. These thin films show antimicrobial properties and cyto-compatibility with NIH 3T3 mouse embryonic fibroblast cells. The porosity and thickness of the films were controlled by varying RPM of the spin coater. Interestingly, at 1000 RPM the roughness of the film decreased with increasing concentrations of FO NPs in PCL, whereas the surface energy increased with increasing FO NPs concentrations. Furthermore, the spreading of NIH-3T3 cells grown on PCL-xFO thin films was less as compared to control (TCPS), however cells overcame this effect after 48 h of seeding and cells spread similarly to those grown on TCPS after 48 h. Also, the incorporation of FO NPs in thin films induced inner membrane permeabilization in E. coli bacteria leading to bacterial cell death. The viability of E. coli bacteria decreased with increasing concentration of FO NPs in PCL. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 795-804, 2017.