Antibacterial effects of graphene- and carbon-nanotube-based nanohybrids on Escherichia coli: Implications for treating multidrug-resistant bacteria

Soyoung Baek, Sung Hee Joo, Chunming Su, Michal J Toborek

Research output: Contribution to journalArticle

Abstract

Some nanomaterials including Fe0, Ag0, and ZnO are well known for their antibacterial effects. However, very few studies have examined antibacterial effects of nanohybrids. Given that metal oxides, mainly ZnO and TiO2, are known to increase mobility, surface area, and photocatalysis when combined with carbon-based nanomaterials, ZnO- and TiO2-conjugated carbon nanotube and graphene oxide nanohybrids were investigated for their antibacterial effects on Escherichia coli (DH5α, a multidrug-resistant coliform bacterium). Graphene-oxide (GO)-based nanohybrids (ZnO–GO and TiO2–GO) induced increased dispersion compared to carbon-nanotube (CNT)-based nanohybrids (ZnO–CNT and TiO2–CNT). Among the four types of nanohybrids, ZnO-conjugated nanohybrids exhibited a higher antibacterial property, resulting in the antibacterial effect (measured with growth inhibition of cells) in the order ZnO–GO > ZnO–CNT > TiO2–GO > TiO2–CNT. Among four possible antibacterial mechanisms (generation of reactive oxygen species (ROS), physicochemical characteristics, the steric effect, and release of metal ions), a primary mechanism—ROS generation—was identified; whereas, physicochemical characteristics and the steric effect were part of contributing mechanisms. The increasing dispersion of TiO2/ZnO on GO may have contributed to the antibacterial effects due to increasing surface areas. Similarly, significant damages to E. coli cell membranes were found by the GO sheet with its sharp edges. Our results suggest that applying GO-based ZnO or TiO2 could be an effective antibacterial method, especially for the treatment of multidrug-resistant bacteria in the water.

Original languageEnglish (US)
Pages (from-to)214-223
Number of pages10
JournalJournal of Environmental Management
Volume247
DOIs
StatePublished - Oct 1 2019

Fingerprint

Graphene
Escherichia coli
Carbon nanotubes
Bacteria
bacterium
Oxides
oxide
Nanostructured materials
Coliform bacteria
surface area
Photocatalysis
Cell membranes
coliform bacterium
Metal ions
carbon nanotube
effect
Cells
Carbon
Oxygen
membrane

Keywords

  • Antibacterial activity
  • Antibacterial-resistant bacteria
  • Carbon nanotube
  • E. coli (DH5α)
  • Graphene oxide
  • Nanohybrids

ASJC Scopus subject areas

  • Environmental Engineering
  • Waste Management and Disposal
  • Management, Monitoring, Policy and Law

Cite this

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title = "Antibacterial effects of graphene- and carbon-nanotube-based nanohybrids on Escherichia coli: Implications for treating multidrug-resistant bacteria",
abstract = "Some nanomaterials including Fe0, Ag0, and ZnO are well known for their antibacterial effects. However, very few studies have examined antibacterial effects of nanohybrids. Given that metal oxides, mainly ZnO and TiO2, are known to increase mobility, surface area, and photocatalysis when combined with carbon-based nanomaterials, ZnO- and TiO2-conjugated carbon nanotube and graphene oxide nanohybrids were investigated for their antibacterial effects on Escherichia coli (DH5α, a multidrug-resistant coliform bacterium). Graphene-oxide (GO)-based nanohybrids (ZnO–GO and TiO2–GO) induced increased dispersion compared to carbon-nanotube (CNT)-based nanohybrids (ZnO–CNT and TiO2–CNT). Among the four types of nanohybrids, ZnO-conjugated nanohybrids exhibited a higher antibacterial property, resulting in the antibacterial effect (measured with growth inhibition of cells) in the order ZnO–GO > ZnO–CNT > TiO2–GO > TiO2–CNT. Among four possible antibacterial mechanisms (generation of reactive oxygen species (ROS), physicochemical characteristics, the steric effect, and release of metal ions), a primary mechanism—ROS generation—was identified; whereas, physicochemical characteristics and the steric effect were part of contributing mechanisms. The increasing dispersion of TiO2/ZnO on GO may have contributed to the antibacterial effects due to increasing surface areas. Similarly, significant damages to E. coli cell membranes were found by the GO sheet with its sharp edges. Our results suggest that applying GO-based ZnO or TiO2 could be an effective antibacterial method, especially for the treatment of multidrug-resistant bacteria in the water.",
keywords = "Antibacterial activity, Antibacterial-resistant bacteria, Carbon nanotube, E. coli (DH5α), Graphene oxide, Nanohybrids",
author = "Soyoung Baek and Joo, {Sung Hee} and Chunming Su and Toborek, {Michal J}",
year = "2019",
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AU - Toborek, Michal J

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