Preferential killing of bacterial cells by hybrid carbon nanotube-MnO2 nanocomposite synthesized by novel microwave assisted processing

Abstract

We present a comprehensive study on the enhanced effect of CNT addition on the structural, optical, morphological and antibacterial properties of CNT-MnO2 nanocomposite synthesized by microwave assisted processing. X-ray diffraction pattern of the hybrid CNT/MnO2 nanocomposite revealed the shifting of highly oriented MnO2 preferential planes. SEM images show porous MnO2 nanospheres uniformly and discretely attached on the walls of carbon nanotube network. Significant variation in the peak shape and IR absorption intensity with CNT addition, indicate the interaction of CNT ions with MnO2 nanoparticles. Optical studies reveal a decrease in energy band gap caused by a significative reduction of electron-hole recombination in manganese activated CNT nanocomposite favouring photocatalytic activity. The antibacterial activity of pure MnO2 and the CNT/MnO2 hybrid was investigated by using both Gram positive and Gram negative bacteria as test organisms. The hybrid nanocomposite revealed higher antibacterial activity compared with pure MnO2 nanoparticles, due to reduced particle size and high specific surface area of CNT. Also, compared to Gram positive bacteria, Gram negative bacteria shows enhanced antibacterial activity due to the improved particle surface reactivity to visible light through effective charge transfer between MnO2 and CNT content of the nanopowder synthesized through microwave processing.Owing to the high surface area, large inner volume and other important physico-chemical properties, the antibacterial activity of carbon-based nanocomposites may interestingly be studied in the near future.