A glassy carbon electrode modified with graphene oxide, poly(3,4-ethylenedioxythiophene), an antifouling peptide and an aptamer for ultrasensitive detection of adenosine triphosphate.

An antifouling aptasensor is described for voltammetric determination of adenosine triphosphate (ATP). A glassy carbon electrode (GCE) was modified with a graphene oxide and poly(3,4-ethylenedioxythiophene) (GO-PEDOT) composite film by electrodeposition. Next, the zwitterionic peptide (EKEKEKE) was attached. It forms an antifouling layer on the modified GCE and serves as the support for subsequent aptamer immobilization. The resulting aptasensor typically is operated at a potential of 0.18 V (vs. SCE) using hexacyanoferrate as the electrochemical probe. It has a linear response in the 0.1 pM to 1.0 µM ATP concentration range, a 0.03 pM detection limit and a sensitivity of 2674.7 µA·µM-1·cm-2. It has outstanding selectivity, satisfactory reproducibility and desired stability. It was used to quantify ATP in ATP-spiked 10% serum solutions. Graphical abstract Schematic presentation of the construction of the aptamer based electrode for voltammetric determination of ATP.

Direct Detection of Vibrio vulnificus, Vibrio parahaemolyticus, and Vibrio alginolyticus from Clinical and Environmental Samples by a Multiplex Touchdown Polymerase Chain Reaction Assay.

BACKGROUND: Vibrio vulnificus, V. alginolyticus, and V. parahaemolyticus are commonly and opportunistically pathogenic to humans. METHODS: In this study, a novel multiple touchdown polymerase chain reaction method (MT-PCR) was developed to benefit rapid and simultaneous detection of the presence of the three Vibrio species from the enriched clinical and environmental samples. RESULTS: The method showed a sensitivity of 104 colony forming units (CFU)/mL for V. vulnificus, 103 CFU/mL for V. parahaemolyticus and V. alginolyticus, and a specificity of 100% for all the three Vibrio species. All strains of the three Vibrio species were detected in the spiked samples artificially contaminated with reference strains and were identified directly from the enriched clinical and environmental samples within three hours by this MT-PCR assay. All the corresponding bacteria were isolated from these enriched samples in 48 hours by standard microbiologic procedures. CONCLUSIONS: This MT-PCR method, which can detect V. vulnificus, V. parahaemolyticus, and V. alginolyticus directly and simultaneously, was rapid, sensitive, specific, and can be used in clinical diagnostics, food industry studies, and risk assessment of environment.