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Nagatani N, Takeuchi A, Anwar Hossain M, Yuhi T, Endo T, Kerman K, Takamura Y, Tamiya E. Rapid and sensitive visual detection of residual pesticides in food using acetylcholinesterase-based disposable membrane chips. Food Control 2007. [DOI: 10.1016/j.foodcont.2006.05.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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52
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A fluorescent biosensor based on acetylcholinesterase and 5-oxazolone derivative immobilized in polyvinylchloride (PVC) matrix. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcatb.2007.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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53
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Shulga O, Kirchhoff JR. An acetylcholinesterase enzyme electrode stabilized by an electrodeposited gold nanoparticle layer. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2006.11.021] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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54
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Vamvakaki V, Chaniotakis NA. Pesticide detection with a liposome-based nano-biosensor. Biosens Bioelectron 2007; 22:2848-53. [PMID: 17223333 DOI: 10.1016/j.bios.2006.11.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 10/06/2006] [Accepted: 11/20/2006] [Indexed: 11/21/2022]
Abstract
Monitoring of the organophosphorus pesticides dichlorvos and paraoxon at very low levels has been achieved with liposome-based nano-biosensors. The enzyme acetylcholinesterase was effectively stabilized within the internal nano-environment of the liposomes. Within the liposomes, the pH sensitive fluorescent indicator pyranine was also immobilized for the optical transduction of the enzymatic activity. Increasing amounts of pesticides lead to the decrease of the enzymatic activity for the hydrolysis of the acetylcholine and thus to a decrease in the fluorescent signal of the pH indicator. The decrease of the liposome biosensors signal is relative to the concentration of dichlorvos and paraoxon down to 10(-10)M levels. This biosensor system has been applied successfully to the detection of total toxicity in drinking water samples. Also a colorimetric screening device for pesticide analysis has been evaluated.
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Affiliation(s)
- Vicky Vamvakaki
- Laboratory of Analytical Chemistry, Department of Chemistry, University of Crete, Vassilika Vouton 71 003, Iraklion Crete, Greece
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55
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Hai A, Ben-Haim D, Korbakov N, Cohen A, Shappir J, Oren R, Spira ME, Yitzchaik S. Acetylcholinesterase–ISFET based system for the detection of acetylcholine and acetylcholinesterase inhibitors. Biosens Bioelectron 2006; 22:605-12. [PMID: 16529923 DOI: 10.1016/j.bios.2006.01.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 01/21/2006] [Accepted: 01/24/2006] [Indexed: 10/24/2022]
Abstract
A bioelectronic hybrid system for the detection of acetylcholine esterase (AChE) catalytic activity was assembled by way of immobilizing the enzyme to the gate surface of an ion-sensitive field-effect transistor (ISFET). Photometric methods used to characterize bonded enzyme and linker layers on silicon substrates confirm the existence of a stable amino-cyanurate containing AChE monolayer. The transduction of the enzyme-functionalized ISFET, in ionic solutions, is detected in response to application of acetylcholine (ACh). Recorded sensitivity of the modified ISFET to ACh has reached levels of up to 10(-5)M. The Michaelis-Menten constant of the immobilized AChE is only moderately altered. Nevertheless, the maximum reaction velocity is reduced by over an order of magnitude. The ISFET response time to bath or ionophoretic application of ACh from a micropipette was in the range of a second. The catalytic activity of the immobilized AChE is inhibited in a reversible manner by eserine, a competitive inhibitor of AChE. We conclude that the immobilized enzyme maintains its pharmacological properties, and thus the described bioelectronic hybrid can serve as a detector for reagents that inhibit AChE activity.
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Affiliation(s)
- Aviad Hai
- Department of Neurobiology, The Life Sciences Institute, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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57
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Stoytcheva M, Zlatev R, Valdez B, Magnin JP, Velkova Z. Electrochemical sensor based on Arthrobacter globiformis for cholinesterase activity determination. Biosens Bioelectron 2006; 22:1-9. [PMID: 16376069 DOI: 10.1016/j.bios.2005.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 11/11/2005] [Accepted: 11/17/2005] [Indexed: 11/19/2022]
Abstract
The sensors applied recently for determination of cholinesterase activity are mostly enzymatic amperometric sensors, in spite of their disadvantages: short life-time at ambient temperature, instability of the response, interferences, as well as passivation of the electrode surface. In the present paper a new approach for determination of cholinesterase activity was proposed, overcoming the main drawbacks of the analysis performed with amperometric enzymatic sensors. Instead of the immobilization of enzymes on a conducting electrode surface, whole cells of Arthrobacter globiformis, containing choline oxidase were fixed on a Clark type oxygen probe. Current proportional to bacteria respiration is registered as a sensor response. The application of whole cells of bacteria as a sensing element permits to achieve high stability of the response and long life-time of the sensor at ambient temperature, due to the conservation of the enzyme in its natural micro-environment inside the immobilized cells. The proposed sensor keeps its functionality more than 7 weeks stored in deionized water at ambient temperature. For the first 2 weeks the amplitude of the response decreases with only 10% and at the end of the studied 7 weeks period the response was 50% of the initial. The other advantages of the proposed sensor are: the dissolved oxygen is used as a mediator which concentration can be reliably and interferences free measured by the aim of a Clark type oxygen probe applied as a transducer; reproducible bacterial membranes can be elaborated by filtration of resuspended bacterial culture after preliminary determination of its activity; application of membranes containing lyophilized bacteria capable to be conserved infinitely long time and activated just before their application; negligible cost compared with the sensors based on immobilized enzymes. The steady-state response of the proposed bacterial sensor to choline obtained in 200 s is linear in the investigated concentration range up to 2 x 10(-4) moldm(-3), with detection limit of 8 x 10(-8) moldm(-3) and sensitivity of 4 x 10(-1) microAcm(3)mol(-1), at pH 6, temperature of 25 degrees C and stirring rate of 300 rpm. Choline is formed as a result of the catalytic hydrolysis (depending on the cholinesterase activity) of the substrate acetylcholine. Linear calibration graph for cholinesterase activity determination was obtained in the range up to 11 mUcm(-3), with a slope of 1.97 x 10(-2) microAcm(3)mU(-1), at pH 6, temperature of 25 degrees C and stirring rate of 300 rpm. The tests with reconstituted lyophilized serum with known activity used as a control sample confirm the accuracy of the proposed method. The relative error of the determination was only 2.82%.
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Affiliation(s)
- Margarita Stoytcheva
- University of Mining and Geology, Department of Chemistry, Studentski grad, 1700 Sofia, Bulgaria.
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58
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Muñoz E, Colina A, Heras A, Ruiz V, Palmero S, López-Palacios J. Electropolymerization and characterization of polyaniline films using a spectroelectrochemical flow cell. Anal Chim Acta 2006; 573-574:20-5. [PMID: 17723500 DOI: 10.1016/j.aca.2006.01.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/09/2006] [Accepted: 01/10/2006] [Indexed: 11/19/2022]
Abstract
A new spectroelectrochemical flow cell is presented and its capability to provide a better understanding of reaction mechanisms is illustrated with the study of the electrosynthesis and characterization of a conducting polymer, polyaniline (PANI). A spectroelectrochemical study of electropolymerization of aniline under flow conditions has been performed for the first time. The significant influence that the flow rate of feeding monomer solution has on the electropolymerization process and, consequently, on the electrochromic properties of the resulting polymer has been demonstrated.
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Affiliation(s)
- Emma Muñoz
- Area de Química Analítica. Universidad de Burgos, Pza. Misael Bañuelos, s/n. 09001 Burgos, Spain
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59
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Okugaichi A, Torigoe K, Yoshimura T, Esumi K. Interaction of cationic gold nanoparticles and carboxylate-terminated poly(amidoamine) dendrimers. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.08.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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60
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Shcharbin D, Jokiel M, Klajnert B, Bryszewska M. Effect of dendrimers on pure acetylcholinesterase activity and structure. Bioelectrochemistry 2006; 68:56-9. [PMID: 15923153 DOI: 10.1016/j.bioelechem.2005.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Revised: 03/21/2005] [Accepted: 04/07/2005] [Indexed: 10/25/2022]
Abstract
The effect of polyamidoamine (PAMAM) dendrimers on activity and fluorescence of pure acetylcholinesterase (EC 3.1.1.7.) was studied. It has been shown that all dendrimers studied decreased the enzymatic activity of acetylcholinesterase. This effect depended on the type of dendrimers. The data on the intrinsic fluorescence have shown that the dendrimers changed acetylcholinesterase conformation and the strongest effect was induced by PAMAM G3.5 dendrimer.
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Affiliation(s)
- D Shcharbin
- Department of General Biophysics, University of Lodz, 12/16 Banacha St., 90-237 Lodz, Poland
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61
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Shi X, Lesniak W, Islam MT, MuÑiz MC, Balogh LP, Baker JR. Comprehensive characterization of surface-functionalized poly(amidoamine) dendrimers with acetamide, hydroxyl, and carboxyl groups. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.07.031] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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62
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Longobardi F, Solfrizzo M, Compagnone D, Del Carlo M, Visconti A. Use of electrochemical biosensor and gas chromatography for determination of dichlorvos in wheat. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:9389-94. [PMID: 16302752 DOI: 10.1021/jf051882u] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Two methods for the determination of dichlorvos in durum wheat by electrochemical assay and gas chromatography, respectively, have been developed. Dichlorvos, an organophosphorus anticholinesterase pesticide, was extracted from wheat with hexane, and the filtered extract was directly analyzed by gas chromatography with nitrogen-phosphorus flame detection (NPD). Recoveries of dichlorvos from milled wheat spiked at 0.25-1.5 microg/g ranged from 96.5 to 100.9%, and the limit of detection was 0.02 microg/g. The electrochemical assay was based on the detection of choline, the acetylcholinesterase product, via a choline oxidase biosensor. An aliquot of the filtered hexane extract was partitioned with phosphate buffer solution, and the organic layer was evaporated prior to electrochemical analysis. A limit of detection of 0.05 microg/g of dichlorvos was obtained with mean recoveries of 97-103% at spiking levels of 0.25-1.5 microg/g. A good correlation (r = 0.9919) was found between the results obtained with the electrochemical and those obtained with the gas chromatographic methods. The electrochemical method was peer-validated in two laboratories that analyzed 10 blind samples (5 duplicates), including a blank and 4 spiked samples with dichlorvos at levels of 0.25, 0.60, 1.00, and 1.50 microg/g. Within-laboratory repeatability (RSDr) and between-laboratory reproducibility (RSDR) ranged from 5.5 to 7.8% and from 9.9 to 17.6%, respectively.
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63
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Nikolelis DP, Simantiraki MG, Siontorou CG, Toth K. Flow injection analysis of carbofuran in foods using air stable lipid film based acetylcholinesterase biosensor. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2004.12.086] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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64
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Del Carlo M, Pepe A, Mascini M, De Gregorio M, Visconti A, Compagnone D. Determining pirimiphos-methyl in durum wheat samples using an acetylcholinesterase inhibition assay. Anal Bioanal Chem 2005; 381:1367-72. [PMID: 15747116 DOI: 10.1007/s00216-004-3013-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 11/30/2004] [Accepted: 12/03/2004] [Indexed: 10/25/2022]
Abstract
An electrochemical assay used for detecting acetylcholinesterase (AChE) inhibitors has been optimised to detect pirimiphos-methyl in durum wheat. Pirimiphos-methyl is a phosphothionate insecticide and so it needs to be transformed into the corresponding oxo form to act as an effective AChE inhibitor. The inhibition assay was based on the electrochemical detection of the product of AChE, choline, via choline oxidase biosensors obtained with Prussian-Blue modified screen printed electrodes. The procedure for the oxidation of pirimiphos methyl via N-bromosuccinimide (NBS) and AChE inhibition was optimised for reagent concentrations and inhibition time in a buffer solution. A calibration of the pirimiphos-methyl (25-1,000 ng/ml) was obtained in the buffer. The intra-electrode CV ranged between 1.6 and 15.0, whereas the inter-electrode CV ranged between 4.6 and 16.0. The detection limit (LOD) was 38 ng/ml, and the I(50%) was 360 ng/ml. The assay conditions were then re-optimised to work with durum wheat extracts, and the calibrations were obtained under different experimental conditions, such as sample pretreatment (milled or whole grains) and extract concentration. The calibrations were slightly affected by the sample matrix, resulting in an increased LOD (65-133 ng/ml) and I(50%) (640-1,650 ng/ml). The LOD found for the sample, determined under optimal conditions, was 3 mg/kg. Spiked samples were prepared at the EU regulated level (5 mg/kg) and analysed with the optimised protocol, resulting in an average recovery of 70.3%.
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Affiliation(s)
- Michele Del Carlo
- Department of Food Science, University of Teramo, Via Carlo R. Lerici 1, Mosciano Stazione, 64023 Teramo, Italy.
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65
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Chao CM, Wang GP, Wu KH, Chang TC. Synthesis and characterization of polyaniline-polyamidoamine dendrimer blends. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/polb.20633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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