Biosensor For Pesticides Research Articles

Electrochemical (Bio)Sensors for Pesticides Detection Using Screen-Printed Electrodes.

Pesticides are among the most important contaminants in food, leading to important global health problems. While conventional techniques such as high-performance liquid chromatography (HPLC) and mass spectrometry (MS) have traditionally been utilized for the detection of such food contaminants, they are relatively expensive, time-consuming and labor intensive, limiting their use for point-of-care (POC) applications. Electrochemical (bio)sensors are emerging devices meeting such expectations, since they represent reliable, simple, cheap, portable, selective and easy to use analytical tools that can be used outside the laboratories by non-specialized personnel. Screen-printed electrodes (SPEs) stand out from the variety of transducers used in electrochemical (bio)sensing because of their small size, high integration, low cost and ability to measure in few microliters of sample. In this context, in this review article, we summarize and discuss about the use of SPEs as analytical tools in the development of (bio)sensors for pesticides of interest for food control. Finally, aspects related to the analytical performance of the developed (bio)sensors together with prospects for future improvements are discussed.

Docking and Molecular Dynamics Predictions of Pesticide Binding to the Calyx of Bovine β-Lactoglobulin.

Pesticides are used extensively in agriculture, and their residues in food must be monitored to prevent toxicity. The most abundant protein in cow’s milk, β-lactoglobulin (BLG), shows high affinity for diverse hydrophobic ligands in its central binding pocket, called the calyx. Several of the most frequently used pesticides are hydrophobic. To predict if BLG may be an unintended carrier for pesticides, we tested its ability to bind 555 pesticides and their isomers, for a total of 889 compounds, in a rigid docking screen. We focused on the analysis of 60 unique molecules belonging to the five pesticide classes defined by the World Health Organization, that docked into BLG’s calyx with ΔGs ranging from −8.2 to −12 kcal mol−1, chosen by statistical criteria. These “potential ligands” were further analyzed using molecular dynamic simulations, and the binding energies were explored with Molecular Mechanics/Generalized Born/Surface Area (MMGBSA). Hydrophobic pyrethroid insecticides, like cypermethrin, were found to bind as deeply and tightly into the calyx as BLG’s natural ligand, palmitate; while polar compounds, like paraquat, were expelled. Our results suggest that BLG could be a carrier for pesticides, in particular for pyrethroid insecticides, allowing for their accumulation in cow’s milk beyond their solubility restrictions. This analysis opens possibilities for pesticide biosensor design based on BLG.

Modification of Oligo- and Polylactides With Macrocyclic Fragments: Synthesis and Properties.

Products of lactic acid polycondensation (poly- and oligolactic acids) are widely used as packaging materials, drug delivery agents, implants etc. Variety of their applications is caused by a number of practically important properties, e.g., biocompatibility and biodegradability, non-toxicity, and mechanical durability. Modification of these polymers with different additives allows improving their properties and extending future applications. In this manner, stability toward degradation, recognition of some substrates, extended thermal stability etc. can be improved. Macrocyclic compounds are promising candidates as modifiers. They are able to provide polymer materials with additional binding sites, impart certain orientation to spatial arrangement of polymer chains, change hydrophilic-lipophilic balance, and redox properties. The latter one can be used for assembling various electrochemical sensors and biosensors that combine steric discrimination of the analytes caused by oligolactides and highly sensitive response to their quantities caused by redox labels introduced. Different composite materials based on oligolactides as matrices for such redox labels were described in the assemblies of biosensors for drugs, pesticides, and antioxidants detection. In this mini-review, methods for the synthesis of the lactic acid oligomers and those modified with the macrocyclic fragments (porphyrin, cyclodextrin, and cyclophane) have been described. The effects of modifiers on complexation, thermal, and aggregation properties of materials are described. Analytical performance of oligolactide based sensors and biosensors has been considered with particular emphasis to the mechanism of signal generation.

Nanocomposites of Pt nanoparticles anchored on UiO66-NH2 as carriers to construct acetylcholinesterase biosensors for organophosphorus pesticide detection

Pt nanoparticle-anchored zirconium-based metal organic framework nanocomposites (Pt@UiO66-NH2) with large surface areas and highly dispersed Pt nanoparticles were synthesized and applied to prepare acetylcholinesterase (AChE) biosensors for organophosphorus pesticides (OPs) detection. Because of integrative impact of excellent electron conduction channels and the increasing of adsorption sites of Pt@UiO66-NH2 as well as the ultrahigh surface area to increase AChE immobilization, the prepared biosensors exhibited high sensitivity towards malathion (as a model for OPs), malathion was detected ranging from 1 × 10−14 M to 1 × 10−9 M and 4.9 × 10−15 M was regarded as limit of detection. The biosensors also displayed accurately. Moreover, the Pt@UiO66-NH2/GCE was used to detect OPs in cabbage and apple samples. This study manifests the profound potential of metal nanoparticle/MOF composites for biosensors with improved electrochemical performance.

Molecular mechanism investigation on the interaction of Clothianidin with human serum albumin

With the widespread application of neonicotinoid insecticides, Clothianidin has received much attention due to the potential harm to human health and ecological environment. However, the mechanism of Clothianidin's underlying toxicity to organisms remains unclear. In this work, the interaction between Clothianidin and human serum albumin was investigated and the intrinsic fluorescence of human serum albumin got quenched via static mechanisms upon the addition of Clothianidin. The binding constants between Clothianidin and human serum albumin at three different temperature were obtained to be 3.543 × 104, 2.995 × 104, and 2.490 × 104 M−1, respectively. Based on the van't Hoff equation, the thermodynamic parameters, ΔH0 and ΔS0 were estimated to be −53.885 KJ mol−1 and −110.535 J mol−1K−1, respectively. A single binding site was predicted from the binding constants at different temperatures by multiple spectroscopic techniques and the negative values of ΔH0 and ΔS0 indicated the binding of human serum albumin with Clothianidin was driven by hydrogen bonds or van der Waals forces. Furthermore, the loose and unfolded secondary structure of human serum albumin along with the addition of clothianidin had been observed through ultraviolet-visible absorption and circular dichroism spectra. In addition, it was also found that Clothianidin had polar effects of structural microenviroment not only on Trp but also Tyr residues from synchronous fluorescence analysis. This study illuminates the molecular mechanism of the interaction between human serum albumin and clothianidin for the first time and helps to construct a specific pesticide biosensor system of human health.

3D graphene/copper oxide nano-flowers based acetylcholinesterase biosensor for sensitive detection of organophosphate pesticides

In the present study, we developed a highly sensitivity electrochemical acetylcholinesterase (AChE, E.C.3.1.1.7) biosensor for organophosphorous pesticides (OPs) detection on the basis of three dimensional graphene-copper oxide nanoflowers nanocomposites (3DG-CuO NFs). The 3DG-CuO NFs nanocomposites with network-like structure not only increase the effective specific surface area, but also provide a favorable microenvironment for AChE loading, which could improve the biosensor performance. The electrochemical performance of the AChE-CS/3DG-CuO NFs/GCE biosensor was thoroughly investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), amperometry (i–t) and square wave voltammetry (SWV). Under the optimal detection conditions, the AChE-CS/3DG-CuO NFs/GCE biosensor exhibits advantages such as a wide linear relationship to malathion ranging from 1 ppt to 15.555 ppb (3 pM-46.665 nM). The theoretical detection limit was calculated to be 0.31 ppt (0.92 pM) with good selectivity and ideal stability. Most importantly, satisfactory recoveries were achieved in real samples analysis, indicating that our developed biosensor has great potential to be an effective platform for pesticides detection.

A broad spectrum amperometric pesticide biosensor based on glutathione S-transferase immobilized on graphene oxide-gelatin matrix

In this work we have fabricated a glutathione-S-transferase based amperometric biosensor for pesticides by immobilizing the enzyme on platinum electrode using graphene oxide-gelatin matrix, evaluated various biosensor parameters, applied the same for detection and quantification of four different classes of pesticides and validated the biosensor results with GC–MS analysis. The enzyme immobilization was confirmed through scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The apparent Michaelis-Menten constant for the immobilized glutathione-S-transferase in the said matrix was found to be 0.083 mmol L−1 and 0.15 mmol L−1 respectively for glutathione and 1-Chloro-2,4-dinitrobenzene. Substrate specificity found to be 2.56 × 107 s−1 M−1 for glutathione and 2.15 × 107 s−1 M−1 for 1-Chloro-2,4-dinitrobenzene. Pesticide analysis was done in 25% methanol solution. The biosensor is a promising new tool for pesticide analysis as it can be applied for analysis of a broad spectrum of pesticides covering at least six different classes namely - benzamidazole, organochlorine, organothiophosphate, organocarbamate, polyphenol and pyrethroid.

Stripe‐shaped Electrochemical Biosensor for Organophosphate Pesticide

AbstractDetection of organophosphate pesticides is indispensable to improve the quality of the water and therefore required by the European Union law. Here, we propose a novel architecture of a pesticide biosensor where the enzyme and the electrode are placed into neighboring zones in the stripe form. This separation permits to use the optimal conditions for their immobilization resulting in undisrupted mechanical stability of the biosensor. The enzyme, acetylcholinesterase, generates thiocholine which is further oxidized at the carbon nanoparticles film electrode, exhibiting high electrocatalytic activity. The whole device was tested as a biosensor for malaoxon employing a wild or recombinant acetylcholinesterase. The latter allowed for incubation time decrease down to 10 minutes and lowered the detection limit to 0.25 nM. Moreover, the encapsulated enzyme activity was visualised by a scanning electrochemical microscopy.

Multicolor sensor for organophosphorus pesticides determination based on the bi-enzyme catalytic etching of gold nanorods

Compared with optical density variations, human eyes are more sensitive to color variations. Herein, we develop a multicolor biosensor for organophosphorus pesticides (OPs) detection based on the enzymatic etching of gold nanorods (AuNRs). In the presence of acetylcholinesterase (AChE) and choline oxidase (CHO), the substrate acetylcholine (ACh) is catalyzed to generate H2O2. The resultant H2O2 etches AuNRs and lead to the etching of AuNRs, accompanying with distinct color changes. OPs inhibit the activity of AChE, which prevent the generation of H2O2 and the etching of AuNRs. Visual semi-quantitative determination of OPs is significantly improved due to multiple colors are presented in this biosensor. LSPR shift (ΔW), after and before inhibition, was utilized to quantitatively measure OPs. Under optimum conditions, the LSPR band shift of AuNRs are linearly dependent on the logarithm of inhibitor concentration over the ranges from 0.01 to 50 μg/L and from 1.0 to 500 μg/L, for dichlorvos and demeton, respectively. LOD are much lower than the maximum residue limits specified in the U.S Department of Agriculture and European Union pesticide regulations. They are also lower than those obtained by previously reported colorimetric methods.

Current progress in biosensors for organophosphorus pesticides based on enzyme functionalized nanostructures: a review

Organophosphorus pesticides analysis has become an increasingly significant research area due to their widespread application and contamination of the environment.

A novel biosensor based on ball-flower-like Cu-hemin MOF grown on elastic carbon foam for trichlorfon detection.

In this study, ball-flower-like Cu-hemin MOFs microstructures supported by flexible three-dimensional (3D) nitrogen-containing melamine carbon foam composites (denoted as Cu-H MOFs/NECF) were constructed. They were used for the immobilization of acetylcholinesterase (AChE) to detect trichlorfon, a widely applicable organophosphorus pesticide (OP). The formation of Cu-H MOFs/NECF was confirmed by scanning electron microscopy, X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The results indicated that ball-flower-like Cu-hemin MOF microstructures were evenly grown on the fibers of 3D-NECF via a simple room temperature mixing method, which could greatly increase the effective surface area. The Cu-H MOFs/NECF composites also overcome the disadvantages of carbon foam materials such as too large pore diameters that always lead to the stacking of the protease and poor conductivity. Moreover, the composites contain nitrogen elements not only from melamine but also from hemin, which is bound to greatly increase the biocompatibility. The composites were directly used to immobilize a large number of AChE to prepare integrated AChE/Cu-H MOFs/NECF electrodes. Simultaneously, the integrated electrode showed better performance for trichlorfon detection. The sensor exhibited good stability and toughness, wide linear range (0.25–20 ng mL−1) and low detection limit (0.082 ng mL−1). Hence, the AChE/Cu-H MOFs/NECF trichlorfon sensor could be a valuable platform for the pesticide residues field testing.

Fluorescence Resonance Energy Transfer-based Biosensor Composed of Nitrogen-doped Carbon Dots and Gold Nanoparticles for the Highly Sensitive Detection of Organophosphorus Pesticides.

The present article reports a novel biosensor for organophosphorus pesticides based on fluorescence resonance energy transfer (FRET) between nitrogen-doped carbon dots (NC-dots) and gold nanoparticles (AuNPs). The effective NC-dots/AuNPs assembly through the Au-N interaction results in good fluorescence quenching. Active acetylcholinesterase (AChE) catalyzes the hydrolysis of acetylthiocholine into -SH containing thiocholine to replace the NC-dots and trigger the aggregation of AuNPs. In the presence of paraoxon, the activity of AChE is inhibited, and thus preventing the generation of thiocholine, causing fewer NC-dots to be replaced. As a consequence, the fluorescence intensity gradually decreases with increasing amount of paraoxon. This biosensor does not require any complex synthesis or modification, and the results show a wide detection range of from 10(-4) to 10(-9) g/L with a detection limit of 1.0 × 10(-9) g/L (3.6 × 10(-12) mol/L). Two linear response regions have been reported with a turning point at about 10(-6) g/L and three different factors that would influence the response behavior. These phenomena discussed in detail so as to explain the special response mechanism.

Nanomaterials in electrochemical biosensors for pesticide detection: advances and challenges in food analysis

This overview (with 114 refs.) covers the progress made between 2010 and 2015 in the field of nanomaterial based electrochemical biosensors for pesticides in food. Its main focus is on strategies to analyze real samples. The review first gives a short introduction into the most often used biorecognition elements. These include (a) enzymes (resulting in inhibition-based and direct catalytic biosensors), (b) antibodies (resulting in immunosensors), and (c) aptamers (resulting in aptasensors). The next main section covers the various kinds of nanomaterials for use in biosensors and includes carbonaceous species (carbon nanotubes, graphene, carbon black and others), and non-carbonaceous species in the form of nanoparticles, rods, or porous materials. Aspects of sample treatment and real sample analysis are treated next before discussing vanguard technologies in tailor-made food analysis.

Studies on electrochemical organophosphate pesticide (OP) biosensor design based on ionic liquid functionalized graphene and a Co3O4nanoparticle modified electrode

In this study, a new type of organophosphate pesticide (OP) biosensor was successfully fabricated based on the immobilization of acetylcholinesterase (AChE) by cross-linking on a glassy carbon electrode (GCE) modified with ionic liquid functionalized graphene (IL-GR), Co3O4nanoparticles and chitosan (CHI).

An Acetylcholinesterase Biosensor Based on Graphene/Polyaniline Composite Film for Detection of Pesticides

AbstractThis work reports a sensitive amperometric biosensor for organophosphate pesticides (OPs) fabricated through modifying glassy carbon electrode with acetylcholinesterase (AChE) immobilized on graphene/polyaniline (G/PANI) composite film. The obtained G/PANI composite films show large specific area, high conductivity, good biocompatibility, and fast redox properties and have perfect layered and encapsulated structures. The as‐prepared biosensor shows high affinity to acetylthiocholine (ATCl) with a Michaelis‐Menten constant value of 0.20 mmol/L. Furthermore, based on the inhibition of the enzymatic activity (immobilized AChE) caused by the model compound of carbaryl (one kind of pesticides), it is found that the inhibition activity of carbaryl is proportional to its concentration ranging from 38 to 194 ng·mL−1. The developed biosensor shows a detection limit of 20 ng·mL−1 (S/N=3) for OPs detection and exhibits good performance such as good reproducibility and acceptable stability, which makes it possible to provide a new and promising tool for the analysis of enzyme inhibitors.

Highly-sensitive organophosphorus pesticide biosensors based on CdTe quantum dots and bi-enzyme immobilized eggshell membranes.

An optical biosensing method using CdTe quantum dots (QDs) and bi-enzyme-immobilized eggshell membranes for the determination of organophosphorus pesticides (OPs) has been developed. Increasing amounts of OPs led to a decrease of the enzymatic activity and thus a decrease in the production of hydrogen peroxide (H2O2), which can quench the fluorescence of the CdTe QDs. Under the optimum conditions, there was a good linear relationship between the enzyme inhibition percentage and the logarithm of paraoxon or parathion concentration in the range of 1.0 × 10(-11)-1.0 × 10(-6) mol L(-1). The detection limit (S/N = 3) of the proposed biosensors were as low as 4.30 × 10(-12) mol L(-1) for paraoxon and 2.47 × 10(-12) mol L(-1) for parathion. The bi-enzyme-immobilized eggshell membrane demonstrated a long shelf-life of at least 2 months and the results showed good repeatability. The proposed method was successfully applied to the determination of the OPs in real fruit samples with satisfactory results.

ATOMIC FORCE MICROSCOPIC AND ELECTROCHEMICAL CHARACTERIZATION OF THE MODIFIED SCREEN PRINTED CARBON ELECTRODE BY SELF ASSEMBLED DEPOSITION OF CHITOSAN AND ACTIVATED CARBON

The surface topographic characteristics generated after a modification of screen printed carbon electrode (SPCE) with either chitosan or activated carbon blending chitosan were closely investigated by atomic force microscopy and a complementary electrochemical techniques. Eighty five percent deacetylation degree chitosan was used at 1% in 1% acetic acid while the activated carbon blending ratio used was 1:1 in chitosan solution. The modification was performed via self assembled deposition directly onto the working electrode surface area. Growth feature of each modified surface was obviously differentiated by all roughness parameters such as an average roughness, root mean square, height different, grain and fractal. The highest roughness value with the least grain was from chitosan modified SPCE. A good correlation result was obtained with electrochemical cyclic voltammetry that a great change in current response was also appeared. Both the modified SPCE by chitosan and activated carbon blending chitosan could produce comparable higher current sensitivity with up to around 0.5 slope value following by their regression coefficient of 0.99. Thus affordable and efficient platforms for a fabrication of desirable pesticide biosensor could be achieved with these modifications as expected.

Efficient immobilization of acetylcholinesterase onto amino functionalized carbon nanotubes for the fabrication of high sensitive organophosphorus pesticides biosensors

This work introduced an efficient immobilization of acetylcholinesterase (AChE) onto amino functionalized carbon nanotubes (CNT–NH2), in order to fabricate high sensitive and practical organophosphorus pesticide (OPs) biosensors. Compared with the pristine, –COOH and –OH decorated CNTs, there were larger amount of enzymes adsorbed on the surface of CNT–NH2 with a favorable orientation and the best amperometric response was obtained on the AChE/CNT–NH2/GC electrode. Furthermore, the biosensor modified with CNT–NH2 showed a high affinity to acetylthiocholine chloride (ATCh) and could catalyze the hydrolysis of ATCh with an apparent Michaelis–Menten constant (Km) value of 67.4µM. Using paraoxon as a model compound, wide linear ranges from 0.2nM to 1nM and 1nM to 30nM, and a low detection limit of 0.08nM were obtained with satisfactory reproducibility and stability. Moreover, the biosensor had also been successfully employed for the determination of low concentrations of pesticides in real vegetable samples. This method could be extended to other functionalized nano–materials for their application in constructing biosensors.

Application of Cationic Poly(lactic‐co‐glycolic acid) Iron Oxide/Chitosan‐Based Nanocomposite for the Determination of Paraoxon

AbstractThe preparation of stable oleic‐acid‐capped iron‐oxide nanoparticles is reported, which were further coated with cationic poly (d,l‐lactic‐co‐glycolic acid) and chitosan in aqueous media by using a nano‐emulsion technique. The prepared composite was used to modify a glassy carbon electrode and the electrochemical behavior and stability of modified electrode were investigated by using cyclic voltammetry. This platform was then utilized to prepare an electrochemical pesticide biosensor based on the inhibition study of the enzyme acetylcholinesterase. Furthermore, the response characteristics show that this fabricated electrode has a shelf life of about 3–4 months and has good adhesion properties along with homogeneous dispersion at the electrode surface. The linear range and detection limit for paraoxon pesticide detection was found to be 9.55–37.1 nM and 8.91 nM, respectively.

Piezoelectric Biosensors for Organophosphate and Carbamate Pesticides: A Review

Due to the great amount of pesticides currently being used, there is an increased interest for developing biosensors for their detection. Among all the physical transducers, piezoelectric systems have emerged as the most attractive due to their simplicity, low instrumentation costs, possibility for real-time and label-free detection and generally high sensitivity. This paper presents an overview of biosensors based on the quartz crystal microbalance, which have been reported in the literature for organophosphate and carbamate pesticide analysis.