Antibacterial activity of PANI coated CoFe2O4 nanocomposite for gram-positive and gram-negative bacterial strains

Abstract

We report on the synthesis of Polyaniline (PANI) coated cobalt ferrite (CoFe2O4) [CoFe2O4/PANI] nanocomposite and study their antibacterial activity for gram-positive (S. aureus, B. subtillis) and gram-negative (E. coli, P. aeruginosa) bacterial strains. PANI coated CoFe2O4 nanocomposites have been synthesized by in-situ chemical oxidative polymerization of aniline monomer on CoFe2O4 nanoparticles, which were synthesized by chemical co-precipitation followed by hydrothermal method. The X-ray diffraction of as-synthesized CoFe2O4 nanoparticles and CoFe2O4/PANI nanocomposite revealed the polycrystalline inverse spinel phase and semi-crystalline nature of PANI. Transmission electron microscope images affirm the incorporation of CoFe2O4 nanoparticles of 5 nm average particle size into the PANI matrix. The saturation magnetization of CoFe2O4/PANI nanocomposites was recorded 50% (54 emu/g to 27 emu/g) in comparison to CoFe2O4 nanoparticles. The antibacterial activity of PANI coated CoFe2O4 nanocomposites were studied by Agar well diffusion method. The results showed a clear inhibition zone, as an antibacterial agent, CoFe2O4/PANI nanocomposites exhibited good antibacterial activity against a different bacterial cell's growth. Growth kinetics studies show that percentage inhibition is relatively higher for P. aeruginosa (~ 92%) than other studied bacteria at 5 mg/ml of the nanocomposites.