Dual-signal amplified electrochemical aptasensor based on Au/MrGO and DNA nanospheres for ultra-sensitive detection of BPA without directly modified working electrode.

Rapid and sensitive analysis of bisphenol A (BPA) is essential for preventing health risks to humans and animals. Hence, a signal-amplified electrochemical aptasensor without repetitive polishing and modification of working electrode was developed for BPA using Au-decorated magnetic reduced graphene oxide (Au/MrGO)-based recognition probe (RP) and DNA nanospheres (DNS)-based signal probe (SP) cooperative signal amplification. The DNS served as a signal molecule carrier and signal amplifier, while Au/MrGO acted as a signal amplifier and excellent medium for magnetic adsorption and separation.

In vitro metabolism of triclosan and chemoprevention against its cytotoxicity.

Triclosan (TCS), a broad-spectrum antibacterial chemical, has been extensively used in personal daily care items, household commodities, and clinical medications; therefore, humans are at risk of being exposed to TCS in their daily lives. This chemical also accumulated in food chains, and potential risks were associated with its metabolism in vivo. The aim of this study was to investigate the difference in metabolic profile of TCS by hepatic P450 enzymes and extrahepatic P450s, and also identify chemical structures of its metabolites.

An ultrasensitive electrochemical biosensor for bisphenol A based on aptamer-modified MrGO@AuNPs and ssDNA-functionalized AuNP@MBs synergistic amplification.

Bisphenol A (BPA) is a harmful endocrine disruptor, sensitive and rapid quantification of BPA is highly desirable. In this work, a novel synergistic signal-amplifying electrochemical biosensor was developed for BPA detection by using a recognition probe (RP) constructed by BPA aptamer modified gold nanoparticles-loaded magnetic reduced graphene oxide (Aptamer-MrGO@AuNPs), and a signal probe (SP) constructed by BPA aptamer-complementary single-stranded DNA (ssDNA) functionalized methylene blue (MB)-loaded gold nanoparticle (ssDNA-AuNP@MBs). The RP and SP can self-assemble to form a stable RP-SP complex through complementary base pairing.

A highly sensitive electrochemical biosensor for Hg based on entropy-driven DNA walker-based amplification.

Herein, a sensitive electrochemical biosensor based on an enzyme-free and entropy-driven DNA walker is presented for the determination of Hg. This biosensor uses Hg as a key to induce a mismatch between thymine-rich oligonucleotides to start the DNA walker, and it utilizes the entropy change of the sensing system to continuously drive the hybridization of oligonucleotides as a driving force for its walking. As the DNA walker runs, the detection signal is amplified to improve the sensitivity of the biosensor.

A fluorescent DNA based probe for Hg(II) based on thymine-Hg(II)-thymine interaction and enrichment via magnetized graphene oxide.

The authors describe a fluorometric assay for the determination of Hg(II). A naphthalimide derivative is used as a label for a thymine (T) rich ssDNA, and graphene oxide magnetized with FeO nanoparticles acts as a quencher and preconcentrators. In the absence of Hg(II), the labeled ssDNA does not separate from the magnetized graphene oxide.

Magnetic separate "turn-on" fluorescent biosensor for Bisphenol A based on magnetic oxidation graphene.

Bisphenol A (BPA) is commonly considered to cause a health hazard to wildlife and humans, acting as an exogenous estrogen. Herein, a magnetic separate "turn-on" fluorescent method for the detection of BPA was proposed based on fluorescence resonance energy transfer (FRET) between fluorescein-labeled BPA aptamer and magnetic oxidation graphene (MGO). At different concentrations of BPA, the fluorescence intensity of the sensing system was varied.

A Fluorescence Sensor for Lead (II) Ions Determination Based on Label-Free Gold Nanoparticles (GNPs)-DNAzyme Using Time-Gated Mode in Aqueous Solution.

This paper describes a label-free 17E DNAzyme-based time-gated fluorescence sensor for Pb detection by unmodified gold nanoparticles (GNPs) and a terbium ternary complex. The fluorophore that used in this paper is a terbium ternary complex. Its signal can be measured in a time-gated manner which could eliminate most of the unspecific fluorescent background.