A new electrochemical aptasensor based on gold/nitrogen-doped carbon nano-onions for the detection of Staphylococcus aureus

Bacterial diseases are serious problems in the world today. The Staphylococcus aureus ( S. aureus) bacterium is one of the most invasive and resistant bacteria that infects humans, making it a common cause of hospital infections. Herein, a very sensitive aptasensor for S. aureus was constructed using nitrogen doped carbon nano-onions, gold nanoparticles (AuNPs) and thiol-terminated, aptamer-modified, screen printed carbon electrodes. The physicochemical characteristics of the nanoparticles and the analytical parameters of the aptasensor were determined by several methods: energy dispersive X-ray spectroscopy, scanning and transmission electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The aptamer was self-assembled on the electrode surface through the covalent modification of thiol groups with AuNPs. The analytical parameters of this sensor were improved by immobilizing a carbon layer on the electrode surface. The developed aptasensor can measure S. aureus quickly with a limit of detection of 3 CFU/mL in the linear range of 10-10(8) CFU/mL. The aptasensor for S. aureus has good repeatability, reproducibility, and long-term stability and can measure S. aureus bacteria in human serum samples. (c) 2021 Elsevier Ltd. All rights reserved.