Optical detection of paraoxon using single-walled carbon nanotube films with attached organophosphorus hydrolase-expressed Escherichia coli

An electrochemical AChE-based biosensor for organophosphate pesticides using a modified CuNWs/rGO nanocomposite on a screen-printed carbon electrode

An enzymatic electrochemical biosensor was built for the indirect detection of organophosphates (OPs), based on acetylcholinesterase inhibition. The biosensor was fabricated for enhanced performance on a screen-printed carbon electrode (SPCE), modified with copper nanowires (CuNWs) composited with reduced graphene oxide (rGO). The oxidation current was measured using the cyclic voltammogram (CV) method, as generated by the enzymatic interaction between acetylcholinesterase (AChE) and its substrate, acetylthiocholine (ATCh). The biosensing response is the reduction in signal caused by the inhibition of acetylcholinesterase in the presence of an organophosphate inhibitor. Benchmarking shows that the CuNWs/rGO nanocomposite enhanced the signal current considerably and decreased the oxidation potential for electrochemical detection of the OP chlorpyrifos, exhibiting a wide linear detection rangefrom 10 µg/L-200 µg/L, with a limit of detection of 3.1 µg/L and limit of quantification of 12.5 µg/L. This sensor is useful for the analysis of chlorpyrifosin drinking water and orange juice, with high recovery rates and no interference effects.

A Microbial Electrochemical Technology to Detect and Degrade Organophosphate Pesticides

Organophosphate (OP) pesticides cause hundreds of illnesses and deaths annually. Unfortunately, exposures are often detected by monitoring degradation products in blood and urine, with few effective methods for detection and remediation at the point of dispersal. We have developed an innovative strategy to remediate these compounds: an engineered microbial technology for the targeted detection and destruction of OP pesticides. This system is based upon microbial electrochemistry using two engineered strains. The strains are combined such that the first microbe (E. coli) degrades the pesticide, while the second (S. oneidensis) generates current in response to the degradation product without requiring external electrochemical stimulus or labels. This cellular technology is unique in that the E. coli serves only as an inert scaffold for enzymes to degrade OPs, circumventing a fundamental requirement of coculture design: maintaining the viability of two microbial strains simultaneously. With this platform, we can detect OP degradation products at submicromolar levels, outperforming reported colorimetric and fluorescence sensors. Importantly, this approach affords a modular, adaptable strategy that can be expanded to additional environmental contaminants.

Easy-to-use and reliable absorbance-based MPH-GST biosensor for the detection of methyl parathion pesticide

•

Simple, inexpensive, high-efficiency absorbance-based OP biosensor was fabricated.

•

Covalently immobilized methyl parathion hydrolase was used as a biomolecule.

•

The biosensor can be used at room temperature for 100 rounds repetitively.

•

The biosensor could detect MP with the detection limit of 0.1 μM.

•

The biosensor showed high reliability for detecting MP in real samples.

Due to high contamination of organophosphate (OP) insecticides in agricultural products and the environment, efficient and convenient devices for their monitoring are necessary. Here, a simple, inexpensive, efficient, and easy-to-use absorbance-based biosensor was fabricated utilizing recombinant methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST), covalently immobilized onto a chitosan film-coated polystyrene microplate, for the detection of methyl parathion (MP) as a representative of OPs. Having been connected to the transducer system designed to work through an Arduino microcontroller, the biosensor could detect MP as efficiently as the conventional methods, with the detection limit of 0.1 μM, the lowest value ever reported for this method. It was stable at 25 °C for 30 days, could function 100 rounds repetitively, and yielded high recovery with real samples. Hence, this simply designed MPH-GST biosensor could be an easy and inexpensive alternative for efficient OP screening at site to help control its contamination.

Recent Progresses in Nanobiosensing for Food Safety Analysis

With increasing adulteration, food safety analysis has become an important research field. Nanomaterials-based biosensing holds great potential in designing highly sensitive and selective detection strategies necessary for food safety analysis. This review summarizes various function types of nanomaterials, the methods of functionalization of nanomaterials, and recent (2014-present) progress in the design and development of nanobiosensing for the detection of food contaminants including pathogens, toxins, pesticides, antibiotics, metal contaminants, and other analytes, which are sub-classified according to various recognition methods of each analyte. The existing shortcomings and future perspectives of the rapidly growing field of nanobiosensing addressing food safety issues are also discussed briefly.