Enhancing Biocide Safety of Milk Using Biosensors Based on Cholinesterase Inhibition.

A sensitive and reliable electrochemical biosensor for the detection of benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC), the most commonly used disinfectant biocides in the agri-food industry, is described. Acetylcholinesterase from (DM AChE) and butyrylcholinesterase from horse serum (BChE) were immobilized by entrapment in a photocrosslinkable polymer on the surface of carbon screen-printed electrodes. Preliminary tests conducted in phosphate buffer showed limits of detection (LODs) of 0.

Targeted and untargeted discovery of UV filters and emerging contaminants with environmental risk assessment on the Northwestern Mediterranean coast.

Marine ecosystems, particularly coastal areas, are becoming increasingly vulnerable to pollution from human activities. Persistent organic pollutants and contaminants of emerging concern (CECs) are recognized as significant threats to both human and environmental health. Our study aimed to identify the molecules present in the seawater of two bathing areas in the Western Mediterranean Sea.

Evaluating cholinesterases inhibition by BAC and DDAC biocides: A combined experimental and theoretical approach.

Disinfectant biocides are chemicals that are heavily used for disinfection purposes in households, hospitals, and agrifood industry. The most common type of biocides are quaternary ammonium compounds (QAs), notably benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC), which have been shown to inhibit cholinesterases. This study aims to evaluate the effect of these biocides towards different cholinesterases using both enzyme inhibition and molecular docking experiments.

Acetylcholinesterase- and Butyrylcholinesterase-Based Biosensors for the Detection of Quaternary Ammonium Biocides in Food Industry.

A sensitive and robust electrochemical cholinesterase-based sensor was developed to detect the quaternary ammonium (QAs) biocides most frequently found in agri-food industry wash waters: benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC). To reach the maximum residue limit of 28 nM imposed by the European Union (EU), two types of cholinesterases were tested, acetylcholinesterase (AChE, from ) and butyrylcholinesterase (BChE, from horse serum). The sensors were designed by entrapping AChE or BChE on cobalt phthalocyanine-modified screen-printed carbon electrodes.

Selection of spore-specific aptamers for Geobacillus stearothermophilus, a food spoilage bacterium.

Due to their ability to form extremely heat resistant spores, anaerobic bacteria are responsible for frequent food spoilage. The development of rapid and specific methods for the detection and quantification of spore contamination is therefore of major interest. In this paper, we describe for the first time the selection of aptamers specific to spores of Geobacillus stearothermophilus (Gbs), which induce flat sour spoilage in vegetable cans.

Spectroelectrochemistry as a new tool for the quantification of UV filters in sun creams.

This study focuses on the spectroelectrochemical quantification of four UV filters, butylmethoxy dibenzoylmethane (BM), benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EM) and octocrylene (OC) used as sunscreens in cosmetics. Three of them exhibited electrochemical activity resulting in the modification of their absorption spectrum under the application of an oxidizing potential of +1.8 V vs.

Monoclonal Antibody-Based Immunosensor for the Electrochemical Detection of Chlortoluron Herbicide in Groundwaters.

Chlortoluron (3-(3-chloro-p-tolyl)-1,1-dimethyl urea) is an herbicide widely used in substitution to isoproturon to control grass weed in wheat and barley crops. Chlortoluron has been detected in groundwaters for more than 20 years; and dramatic increases in concentrations are observed after intense rain outbreaks. In this context; we developed an immunosensor for the determination of chlortoluron based on competitive binding of specific monoclonal antibodies on chlortoluron and immobilized biotinylated chlortoluron; followed by electrochemical detection on screen-printed carbon electrodes.

Development of a new dual electrochemical immunosensor for a rapid and sensitive detection of enrofloxacin in meat samples.

A novel dual electrochemical immunosensor was fabricated for the rapid and sensitive detection of enrofloxacin (EF) antibiotic in meat. Anti-quinolone antibody was immobilized onto screen-printed dual carbon electrodes via carbodiimide coupling. A new electrochemical probe was synthesized by conjugating difloxacin and aminoferrocene, whose oxidation was measured at + 0.

Synthesis and Characterization of Bis-1,2,3-Triazole Ligand and its Corresponding Copper Complex for the Development of Electrochemical Affinity Biosensors.

The bis-triazole ligand and its corresponding copper complexes were synthesized and characterized for the first time and proposed as new labels for the development of electrochemical aptasensors. The bis-triazole ligand was prepared from methyl 1,6-heptadiyne-4-carboxylate and 2-(azidomethyl)phenol using classical CuAAC in presence of different copper salts. The X-ray structure of bis-triazole showed a symmetry center (C1).

Salen/salan metallic complexes as redox labels for electrochemical aptasensors.

This work presents the synthesis and characterization of salen/salan metal complexes for their future application as electrochemical labels in affinity sensors. Due to its stability and electrochemical properties, an oxovanadium salan complex was selected and coupled to an estradiol-specific aptamer. The response of the resulting aptasensor was shown to decrease with increasing estradiol concentration.

Detection of in Food Matrices, from Conventional Methods to Recent Aptamer-Sensing Technologies.

Rapid detection of the foodborne pathogen in food processing is of crucial importance to prevent food outbreaks and to ensure consumer safety. Detection and quantification of species in food samples is routinely performed using conventional culture-based techniques, which are labor intensive, involve well-trained personnel, and are unsuitable for on-site and high-throughput analysis. To overcome these drawbacks, many research teams have developed alternative methods like biosensors, and more particularly aptasensors, were a nucleic acid is used as biorecognition element.

Ultrasensitive label-free electrochemical immunosensor based on PVA-co-PE nanofibrous membrane for the detection of chloramphenicol residues in milk.

An ultrasensitive label-free amperometric immunosensor for the detection of chloramphenicol (CAP) residues in milk has been developed by using a screen-printed carbon electrode laminated with a layer of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane that is covalently immobilized with a CAP antibody (anti-CAP). The performance of the PVA-co-PE nanofiber membrane (PVA-co-PE NFM) on the electrode was compared with a PVA-co-PE casted membrane (PVA-co-PE CM), necessary fabrication steps and performance of the sensors were investigated by electrochemical impedance spectroscopy (EIS). The application of the PVA-co-PE NFM decreased the electron-transfer-resistance by about 4 times compared with a conventional PVA-co-PE casted membrane.

Detection of Bisphenol A in aqueous medium by screen printed carbon electrodes incorporating electrochemical molecularly imprinted polymers.

Electrochemical molecularly imprinted polymers (e-MIPs) were for the first time introduced in screen-printed carbon electrodes (SPCE) as the sensing element for the detection of an organic pollutant. To play this sensing role, a redox tracer was incorporated inside the binding cavities of a cross-linked MIP, as a functional monomer during the synthesis step. Ferrocenylmethyl methacrylate was used for this purpose.

Chemiluminescence immunoassays for estradiol and ethinylestradiol based on new biotinylated estrogen derivatives.

New chemiluminescence-based immunoassays for sensitive detection of 17-β estradiol (E2) and ethinylestradiol (EE2) are described on the basis of the use of biotinylated estrogen derivatives. Estrogen derivatives bearing a carboxylic group (E2-COOH and EE2-COOH) on C-3 position were synthesized, covalently bound to aminated biotin and subsequently immobilized on avidin-coated microtiter plates. The assay principle was based on competition between free and immobilized estrogens for their binding to primary antibodies, with subsequent revelation using horseradish peroxidase (HRP)-labeled secondary antibodies.

Pharmaceuticals released from senior residences: occurrence and risk evaluation.

One of the main pursuits, yet most difficult, in monitoring studies is to identify the sources of environmental pollution. In this study, we have identified health-care facilities from south European countries as an important source of pharmaceuticals in the environment. We have estimated that compounds consumed in by the elderly and released from effluents of senior residences can reach river waters at a concentration higher than 0.

Biosensor-assisted selection of optimal parameters for designing molecularly imprinted polymers selective to phosmet insecticide.

Molecularly imprinted polymers (MIPs) for phosmet insecticide were synthesized by batch polymerization. The affinity of functional monomers to phosmet was tested using an original method involving an electrochemical biosensor based on acetylcholinesterase inhibition. It was demonstrated that association of phosmet with appropriate functional monomers resulted in a decrease of enzyme inhibition.

Selection of DNA aptamers against penicillin G using Capture-SELEX for the development of an impedimetric sensor.

This paper describes for the first time the selection of aptamers selective to penicillin. Aptamers were selected using a specific process called Capture-SELEX (Systematic Evolution of Ligands by Exponential Enrichment). This technique is based on the selection of DNA aptamers using penicillin G in solution while the ssDNA library is fixed on a support.

A novel amperometric biosensor for ß-triketone herbicides based on hydroxyphenylpyruvate dioxygenase inhibition: A case study for sulcotrione.

An amperometric biosensor was designed for the determination of sulcotrione, a β-triketone herbicide, based on inhibition of hydroxyphenylpyruvate dioxygenase (HPPD), an enzyme allowing the oxidation of hydroxyphenylpyruvate (HPP) in homogentisic acid (HGA). HPPD was produced by cloning the hppd gene from Arabidopsis thaliana in E. coli, followed by overexpression and purification by nickel-histidine affinity.

Development of an impedimetric aptasensor for the determination of aflatoxin M1 in milk.

An aptasensor was designed for the determination of aflatoxin M1 (AFM1) in milk based on DNA-aptamer recognition and electrochemical impedance spectroscopy detection. A hexaethyleneglycol-modified 21-mer oligonucleotide was immobilized on a carbon screen-printed electrode through carbodiimide immobilization, after diazonium activation of the sensing surface. Cyclic voltammetry and electrochemical impedance spectroscopy in the presence of ferri/ferrocyanide redox probe were used to characterize each step of the aptasensor development.

Biosensor-based real-time monitoring of paracetamol photocatalytic degradation.

This paper presents for the first time the integration of a biosensor for the on-line, real-time monitoring of a photocatalytic degradation process. Paracetamol was used as a model molecule due to its wide use and occurrence in environmental waters. The biosensor was developed based on tyrosinase immobilization in a polyvinylalcohol photocrosslinkable polymer.

Electrochemical impedimetric sensor based on molecularly imprinted polymers/sol-gel chemistry for methidathion organophosphorous insecticide recognition.

We report here a novel method to detect methidathion organophosphorous insecticides. The sensing platform was architected by the combination of molecularly imprinted polymers and sol-gel technique on inexpensive, portable and disposable screen printed carbon electrodes. Electrochemical impedimetric detection technique was employed to perform the label free detection of the target analyte on the designed MIP/sol-gel integrated platform.

Molecularly imprinted polymer cartridges coupled to high performance liquid chromatography (HPLC-UV) for simple and rapid analysis of fenthion in olive oil.

A combination of molecular modelling and a screening of the library of non-imprinted polymers (NIPs) was used to identify acrylamide as a functional monomer with high affinity towards fenthion, organophosphate insecticide, which is frequently used in the treatment of olives. A good correlation was found between the screening tests and modelling of monomer-template interactions performed using a computational approach. Acrylamide-based molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) were thermally synthesised in dimethyl formamide (porogen) using ethylene glycol dimethacrylate as a cross-linker and 1,1-azo-bis (isobutyronitrile) as an initiator.

Novel bacterial bioassay for a high-throughput screening of 4-hydroxyphenylpyruvate dioxygenase inhibitors.

Plant 4-hydroxyphenylpyruvate dioxygenase (HPPD) is the molecular target of a range of synthetic β-triketone herbicides that are currently used commercially. Their mode of action is based on an irreversible inhibition of HPPD. Therefore, this inhibitory capacity was used to develop a whole-cell colorimetric bioassay with a recombinant Escherichia coli expressing a plant HPPD for the herbicide analysis of β-triketones.

Detection of glycoalkaloids using disposable biosensors based on genetically modified enzymes.

In this work we present a rapid, selective, and highly sensitive detection of α-solanine and α-chaconine using cholinesterase-based sensors. The high sensitivity of the devices is brought by the use of a genetically modified acetylcholinesterase (AChE), combined with a one-step detection method based on the measurement of inhibition slope. The selectivity was obtained by using butyrylcholinesterase (BChE), an enzyme able to detect these two toxins with differential inhibition kinetics.

Immunosensors for estradiol and ethinylestradiol based on new synthetic estrogen derivatives: application to wastewater analysis.

Novel electrochemical immunosensors for sensitive detection of 17-β estradiol (E2) and ethinylestradiol (EE2) are described on the basis of the use of magnetic beads (MBs) as solid support and screen-printed electrodes as sensing platforms. Four synthetic estrogen derivatives containing either a carboxylic group or an amine group at the C-3 position were synthesized and covalently bound to MBs functionalized with amine or carboxyl groups, respectively. The assay was based on competition between the free and immobilized estrogen for the binding sites of the primary antibody, with subsequent revelation using alkaline phosphatase-labeled secondary antibody.