Due to the increasing problem in human health of antibiotic resistance in bacteria, novel modifications of the delivery of antibiotics have become an increasingly popular field of study. Nano-graphene is a novel compound in that it is water soluble, and can be modified to work in many different applications, both biologically and mechanically. Our previous experiments confirmed the modification of graphene into nanoscale graphene oxide (NGO) with the successful attachment of polyethylene glycol (PEG) to increase water solubility. This compound was used to deliver the soluble antibiotic, tetracycline hydrochloride, into resistant bacteria. Escherichia coli, a gram-negative bacterium, was used and contained a plasmid coding for antibiotic resistance via an efflux pump. Our results were able to confirm the presence of PEG and tetracycline hydrochloride on the nano-graphene. The amount of tetracycline hydrochloride attached to the NGO-PEG was quantified using UV spectroscopy, and a minimum inhibitory concentration of NGO-PEG TET HCl was calculated for DH5α, the non-resistant E. coli, and DH5α containing pBR322, the resistance plasmid. The goal of this experiment was to increase the antibiotic attachment onto the nano-graphene oxide, in addition to increasing the inhibition of the resistant bacteria at lower concentrations of nano-graphene oxide with attached antibiotic. This was accomplished by using the molecular (not the hydrochloride salt) form of tetracycline, and repeating previous experiments to find the minimum inhibitory concentration of NGO-PEG TET in the presence of the DH5α and DH5α/pBR322. Growth experiments were conducted with bacteria both lacking and containing the resistance plasmid, and the amount of growth was measured using spectrophotometry and viable bacterial counts.

Antibiotic delivery in resistant Escherichia coli using PEG-modified nano-graphene oxide

251st National Meeting (2016)

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