New Life for an Old Antibiotic

Abstract

Restoring the antibacterial properties of existing antibiotics is of great concern. Herein, we present, for the first time, the formation and deposition of stable antibiotic nanoparticles (NPs) on graphene oxide (GO) sheets by a facile one-step sonochemical technique. Sonochemically synthesized graphene oxide/tetracycline (GO/TET) composite shows enhanced activity against both sensitive and resistant Staphylococcus aureus (S. aureus). The size and deposition of tetracycline (TET) nanoparticles on GO can be controlled by varying the sonication time. The synthesized NPs ranged from 21 to 180 nm. Moreover, ultrasonic irradiation does not cause any structural and chemical changes to the TET molecule as confirmed by Fourier transform infrared spectroscopy (FTIR). The virtue of π-π stacking between GO and TET additionally facilitate the coating of TET NPs upon GO. A time dependent release kinetics of TET NPs from the GO surface is also monitored providing important insights regarding the mechanism of antibacterial activity of GO/TET composites. Our results show that the GO/TET composite is bactericidal in nature, resulting in similar values of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). This composite is found to be active against TET resistant S. aureus at a concentration four times lower than the pristine TET. The sensitive S. aureus follows the same trend showing six times lower MIC values compared to pristine TET. GO shows no activity against both sensitive and resistant S. aureus even at a concentration as high as 1 mg/mL but influences the biocidal activity of the GO/TET composite. We propose that the unique structure and composition manifested by GO/TET composites may be further utilized for different formulations of antibiotics with GO. The sonochemical method used in this work can be precisely tailored for the stable deposition of a variety of antibiotics on the GO surface to reduce health risks and increase the spectrum of applications.

Preparation and evaluation of effect on Escherichia coli and Staphylococcus aureus of radiolabeled ampicillin‐loaded graphene oxide nanoflakes

“…In contrast, Mishra et al. showed that GO alone did not affect bacteria at a concentration ˃1 mg/ml . In our study, the concentration was lower than mentioned concentration.…”

“…Inactivation of PBPs interferes with the cross‐linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. Hence, the bactericidal activity of ampicillin results from the inhibition of cell wall synthesis and is mediated through ampicillin binding to penicillin‐binding proteins (PBPs) …”

“…Many antimicrobial drugs have been used to kill microbes such as bacteria, fungi, and viruses or inhibit their growth mechanism. In recent years, antimicrobial drug‐loaded nanoparticle systems increase therapeutic effectiveness and decrease undesirable side‐effects of the drugs . In literature antibiotics loaded in bovine serum, in cyanoacrylate, liposomes nanoparticles, calcium sulfate nanocomposites, and graphene oxide nanoparticles have been notified.…”

Strategies to prevent the occurrence of resistance against antibiotics by using advanced materials

“…The nano-sized transformation of another antibiotic TET also improved its bactericidal activity, killing both TET sensitive and resistant bacteria (Shimanovich and Lipovsky 2015). Sonochemically synthesised graphene oxide/TET nanocomposites demonstrated enhanced activity against both sensitive and resistant S. aureus when compared to the same concentration of non-transformed antibiotic (Mishra and Segal 2015). TET loaded in protein microspheres showed high bactericidal effect against E. coli and S. aureus (Avivi and Nitzan 2003).…”

Nanomaterials Based Drinking Water Purification: Comparative Study with a Conventional Water Purification Process

“…There have been many structural alteration studies on antibiotics to struggle against this phenomenon [48]. Because of the potential antibacterial applications of graphene and graphene-based nanocomposites [49], conjugation of existing antibiotics with graphene-based materials is a promising solution to prevent antibacterial resistance [50,51].…”