An antibacterial study of a new magnetic carbon nanotube/core-shell nanohybrids

Abstract

Abstract A new magnetic carbon nanotube/core-shell nanohybrid synthesized using Co0.7Zn0.3Fe2O4 as a magnetic core, polyethylene terephthalate (PET) as a binder shell, Silver nanoparticles as antibacterial agents grafted to the shell and carbon nanotube (CNT) as a multifunctional substrate. The synthesized Co0.7Zn0.3Fe2O4/PET/Ag/CNT was characterized using field emission – scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, energy-dispersive X-ray spectroscopy (EDS), Furrier –transform infrared (FT-IR) spectroscopy and Brunauer-Emmett-Teller (BET). FESEM and TEM results confirmed the formation of spherical-like core – shell structures and their distribution on the CNTs. The spinel structure of magnetic ferrite core was demonstrated by XRD analysis. A specific surface area of 58.74 m2/g was recorded by BET measurement. A vibrating sample magnetometer (VSM) was used to determine the magnetic properties of the samples. The saturation magnetization of the nanohybrid was 44.5 emu/g showing its ferro-magnetic behavior. Antibacterial activity of the synthesized nanohybrid against two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and two Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) was assessed by disk diffusion standard and minimal inhibitory concentration method. The zones of inhibition were 14.3 ± 0.6, 15.1 ± 0.6, 18.1 ± 0.6 and 18.2 ± 0.6 mm zone of inhibition (ZOI) for Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively. Also, Zeta potential analysis indicated the good stability of the nanohybrid (100 mV). These finding show that the Co0.7Zn0.3Fe2O4/PET/Ag/CNT nanohybrid is a promising water-dispersible antibacterial material that can easily be removed by applying a suitable magnetic field.