Exchangeable immobilized enzyme reactor for enzyme inhibition tests in flow-injection analysis using a magnetic device. Determination of pesticides in drinking water

Kindervater, R.; Künnecke, Wolfgang; Schmid, Rolf D.

doi:10.1016/s0003-2670(00)83545-x

Cited by 82 publications

(20 citation statements)

References 10 publications

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“…Numerous prototypes based on potentiometric [13,14], amperometric [15][16][17] and piezoelectric [18,19] transducers have been developed. Because the enzymatic activity in AChE-based biosensors is destroyed upon calibration or in the presence of the analyte, the sensor must be discarded after determination [20,21], or, alternatively, the enzyme must be replaced [22][23][24][25] or reactivated [26,27].…”

Section: Introductionmentioning

confidence: 99%

An acetylcholinesterase biosensor for determination of low concentrations of Paraoxon and Dichlorvos

et al. 2011

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The characterization of an economic and ease-to-use carbon paste acetylcholinesterase (AChE) based biosensor to determine the concentration of pesticides Paraoxon and Dichlorvos is discussed. AChE hydrolyses acetylthiocholine (ATCh) in thiocoline (TC) and acetic acid (AA). When AChE is immobilized into a paste carbon working electrode kept at +410 mV vs. Ag/AgCl electrode, the enzyme reaction rate using acetylthiocholine chloride (ATCl) as substrate is monitored as a current intensity. Because Paraoxon and Dichlorvos inhibit the AChE reaction, the decrease of the current intensity, at fixed ATCl concentration, is a measure of their concentration. Linear calibration curves for Paraoxon and Dichlorvos determination have been obtained. The detection limits resulted to be 0.86 ppb and 4.2 ppb for Paraoxon and Dichlorvos, respectively, while the extension of the linear range was up 23 ppb for the former pesticide and up to 33 ppb for the latter. Because the inhibited enzyme can be reactivated when immediately treated with an oxime, the biosensor reactivation has been studied when 1,1 0 -trimethylene bis 4-formylpyridinium bromide dioxime (TMB-4) and pyridine 2-aldoxime methiodide (2-PAM) were used. TMB-4 resulted more effective. The comparison with the behavior of similar AChE based biosensors is also presented.

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Section: Introductionmentioning

confidence: 99%

An acetylcholinesterase biosensor for determination of low concentrations of Paraoxon and Dichlorvos

et al. 2011

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“…Some of the reports on immobilized AChE-based single enzyme system apply voltages of + 400 to + 700 mV for the oxidation of thiocholine. [7][8][9][10] AChE can be immobilized on electrode surface by using a variety of matrices such as cross-linked polymers, [11] crosslinked bovine serum albumin, [12,13] chitosan [2] and cellulose, [14] different support matrices such as nylon, [5,12,15] controlled pore glass, [16] magnetic particles, [10,17] or the strong affinity linking with concanavalin A [18] and metal ions. [19] To reduce the working potential mediators such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) [19][20][21][22] have been deposited on surface to shuttle electrons between the thiocholine formed and the electrode.…”

Section: Introductionmentioning

confidence: 99%

Binding of Acetylcholinesterase to Multiwall Carbon Nanotube‐Cross‐Linked Chitosan Composite for Flow‐Injection Amperometric Detection of an Organophosphorous Insecticide

Kandimalla

2006

Chemistry A European J

109

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A novel method for immobilization of acetylcholinesterase (AChE) by binding covalently to a cross-linked chitosan-multiwall carbon nanotube (MWNT) composite is described. In addition a sensitive, fast, cheap and automatizable flow injection detection of an organophosphorous insecticide was developed. The MWNTs were homogeneously distributed in the chitosan membrane which showed a homogeneous porous structure. The immobilized AChE could catalyze the hydrolysis of acetylthiocholine with a K(M)app value of 177 microM to form thiocholine, which was then oxidized to produce detectable signal in a linear range of 1.0-500 microM and fast response. MWNTs could catalyze the electrooxidation of thiocholine, thus increasing detection sensitivity. Based on the inhibition of an organophosphorous insecticide on the enzymatic activity of AChE, using Sulfotep as a model compound, the conditions for the flow-injection detection of the insecticide were optimized. Both biocompatibility of chitosan and inherent conductive properties of MWNTs favored the detection of the insecticide from 1.5 to 80 microM along with good stability and reproducibility. 95 % reactivation from inhibited AChE could be regenerated by using 2-pyridinealdoxime methiodide within 15 min for 15 times. The detection of Sulfotep samples exhibited satisfactory results. The proposed flow-injection analysis device can be applied to automated determination and characterization of enzyme inhibitors.

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“…Finally, the background fluid is eluted by a buffer in a washing step, leaving behind the magnetically immobilized particle-target conjugate. 6 In contrast to its batch counterpart, a͒ Author to whom correspondence should be addressed. Electronic mail: ikpuri@vt.edu.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of flow-through immunoassay in a microchannel

Sinha

Ganguly

Puri

2010

Journal of Applied Physics

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Immunomagnetic separation (IMS) is a method to isolate biomaterials from a host fluid in which specifically selected antibodies attached to magnetic particles bind with their corresponding antigens on the surface of the target biological entities. A magnet separates these entities from the fluid through magnetophoresis. The method has promising applications in microscale biosensors. We develop a comprehensive model to characterize the interaction between target species and magnetic particles in microfluidic channels. The mechanics of the separation of target nonmagnetic N particles by magnetic M particles are investigated using a particle dynamics simulation. We consider both interparticle magnetic interactions and the binding of the functionalizing strands of complementary particles. The temporal growth of a particle aggregate and the relative concentrations of M and N particles are investigated under different operating conditions. A particle aggregate first grows and then exhibits periodic washaway about a quasisteady mean size. The washaway frequency and amplitude depend on the initial fractional concentration of N particles while the aggregate size scales linearly with the dipole strength and inversely with the fluid flow rate.

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Exchangeable immobilized enzyme reactor for enzyme inhibition tests in flow-injection analysis using a magnetic device. Determination of pesticides in drinking water

Cited by 82 publications

References 10 publications

An acetylcholinesterase biosensor for determination of low concentrations of Paraoxon and Dichlorvos

An acetylcholinesterase biosensor for determination of low concentrations of Paraoxon and Dichlorvos

Binding of Acetylcholinesterase to Multiwall Carbon Nanotube‐Cross‐Linked Chitosan Composite for Flow‐Injection Amperometric Detection of an Organophosphorous Insecticide

Numerical investigation of flow-through immunoassay in a microchannel

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