Functionalized Single-Walled Carbon Nanotubes and Nanographene Oxide to Overcome Antibiotic Resistance in Tetracycline-Resistant Escherichia coli

Abstract

Antibiotic resistance is a significant and growing public health problem. This work investigated the use of two different carbon nanomaterials, single-walled carbon nanotubes (SWNTs) and nanographene oxide (NGO), as a means of delivering the antibiotic tetracycline to a strain of Escherichia coli bacterium with an efflux pump resistance mechanism. Both SWNTs and NGO carrying tetracycline were found to inhibit the resistant strain of Escherichia coli, though the amount of tetracycline delivered was much lower than the minimum inhibitory concentration of free tetracycline. Attachment of the tetracycline to the nanomaterials was found to be necessary for the inhibition of bacterial growth, indicating that the nanomaterials were transporting the antibiotic into the cells and subverting the efflux pump. SWNTs were observed to have greater efficacy in delivering tetracycline than graphene oxide, which is attributed to the SWNTs’ needle-like shape. This work demonstrates both the use of carbon nanomaterials as antibiotic-delivery vehicles and the effect of nanomaterial shape on their efficacy. More importantly, it demonstrates that nanomaterials can successfully extend the life of existing antibiotics, making them an important tool for combatting antibiotic resistance mediated by an efflux pump mechanism.

Nanoantibiotics: Functions and Properties at the Nanoscale to Combat Antibiotic Resistance

“…Most MWNCTs need modification to enhance their antibacterial functions. For instance, silver NPs functionalized with a Carver et al (2020) dendrimer modified MWNCTs bring significant broad-spectrum antibacterial functionalities (Yuan et al, 2008). Table 9 summarizes the existing and future potentials of antibioticsnanoparticle conjugate systems, their associated properties, and antibacterial mechanisms.…”

“…The literature on carbon-based nAbts is quite limited ( Carver et al, 2020 ; Singh et al, 2019 ) as they are not being widely studied. However, they have enormous adsorption capacities suitable as delivery vehicle of pharmaceuticals.…”

“…When a CNT or a nanographene oxide (NGO) penetrates the cell membrane by physically breaking the barrier, they are trapped inside. The efflux pumps cannot eject the drug-carrying nAbts ( Carver et al, 2020 ). Table 4 shows two major carbon-based nAbts and their associated functions.…”

State of the Art in the Antibacterial and Antiviral Applications of Carbon-Based Polymeric Nanocomposites

“…Recent work has investigated the use of different carbon nanomaterials as means of delivering antibiotics to hinder the resistant strain of E. coli [ 7 ]. Attachment of an antibiotic, tetracycline, to the nanomaterials was needed for the restriction of bacterial growth, demonstrating that the nanomaterials were carrying the antibiotic into the cells and destabilizing the efflux pump.…”

“…Those with a needle-like shape showed better activity. Nanomaterials can successfully extend the life of current antibiotics, which makes them a key tool for supporting struggling antibiotic resistance through an efflux pump mechanism [ 7 ].…”