Acetylcholine biosensors

M. Snejdakova, L. Svobodova, D.P. Nikolelis, J. Wang, and D. Hianik, Acetylcholine biosensor based on dendrimer layers for pesticides detection. Electroanalysis 15, 1185—1191 (2003). 

R.E. Gyurcsanyi, Z. Vagfoldi, K. Toth, and G. Nagy Fast response potentiometric acetylcholine biosensor. Electroanalysis 11, 712-718 (1999). 

L. Doretti, D. Ferrara, S. Lora, F. Schiavon and F.M. Veronese, Acetylcholine biosensor involving entrapment of acetylcholinesterase and poly (ethylene glycol)-modified choline oxidase in a poly(vinyl alcohol) cryogel membrane, Enzyme Microb. Technol., 27 (2000) 279-285. 

Chen, Q., Kobayashi, Y., Tekeshita, H., Hoshi, T., Anzai, J. (1998). Avidin-biotin system-based enzyme multilayer membranes for biosensor applications optimization of loading of choline esterase and choline oxidase in the hienzyme membrane for acetylcholine biosensors. Electroanalysis 10 94-7. 

Shi, H., Zhao, Z., Song, Z., Huang, J., Yang, Y., Anzai, J., Osa, T., Chen, Q. (2005). Fabrication of acetylcholine biosensor by a layer-by-layer deposition technique for determining trichlorfon. Electroanalysis 17 1285-90. 

B. (2012) Amperometric acetylcholine biosensor based on self-assembly... 

Sattarahmady N, Heli H, Moosavi-Movahedi AA (2010) An electrochemical acetylcholine biosensor based on nanoshells of hollow nickel microspheres-carbon microparticles-Nalion nanocomposite. Biosens Bioelectron 25 2329-2335... 

Figure 3.9 pH micro-electrode used in the acetylcholine biosensor. 

Fig. 1. Schematic for chemoreceptor-modified ISFET biosensor for detection of acetylcholine where the source and drain are both n-ty e siHcon.

Absorbance- and reflectance-based measurements are widespread, as there are many enzymatic reaction products or intermediates that are colored or if not, can react with the appropriate indicator. Sensors using acetylcholinesterase for carbamate pesticides detection are an example of indirect optical fiber biosensors. This enzyme catalyses the hydrolysis of acetylcholine with concomitant decrease in pH41 ... 

M. Bernabai, C. Cremisini, M. Mascini, and G. Palleschi, Determination of organophosphorus and car-bamic pesticides with a choline and acetylcholine electrochemical biosensor. Anal. Lett. 24, 1317-1331 (1991). 

H.C. Tsai and R.A. Doong, Simultaneous determination of pH, urea, acetylcholine and heavy metals using array-based enzymatic optical biosensor. Biosens. Bioelectron. 20, 1796-1804 (2005). 

Wang, X.-F., et ah, Signat-on electrochemiluminescence biosensors based on CdS-carbon nanotube nanocomposite for the sensitive detection of choline and acetylcholine. Advanced Functional Materials, 2009.19(9) p. 1444-1450. 

Besides this remarkably fast commercial development, other research groups designed their own laboratory-compatible LAPS systems for similar purposes. The use of, e.g., a nicotinic acetylcholine receptor was reported to create a LAPS-receptor biosensor capable of detecting receptor ligands (acetylcholine, carbamylcholine, succinylcholine, sub-eryldicholine, nicotine as well as d-tubocurarine, a-bungarotoxin and a-Naja toxin) [85]. Another system quite similar to the Cytosensor setup was introduced, where mouse fibroblast fine 3T6 cells were chosen to demonstrate the determination of metabolic processes of these cells [86]. 

Another class of enzymes that has found wide application in the biosensor field in the last decades is that of the cholinesterases which have been mainly used for the detection of pesticides. For the amperometric detection of cholinesterase activity, both the substrates acetylcholine and acetylthiocholine have been extensively used [6-9], the latter being preferred because this avoids the use of another enzyme, choline oxidase, which is usually coupled with acetylcholinesterase. However, the amperometric measurement of thiocholine, produced by... 

The construction and response of amperometric biosensors for glucose, acetylcholine, and glutamate based on these polymeric materials are described, and the dependence of sensor response on the polymer structure is discussed. 

Figure 11. Schematic representation of an amperometric biosensor for acetylcholine based on polymeric electron relay systems.

Nicotinic acetylcholine receptor Receptor, isolated from electro-phorus electricus, was incorporated into a polymeric film formed in situ on an electronic transductor containing two terminal 1.5 cm x 1.5 cm interdigitated gold electrode. The response of the biosensor reached equilibrium within 5 s for ACh and remained stable up to 20 min. Detection limits 25 ng in a 50 pL sample (i.e., 0.5 pg/mL). [93]... 

The detection limit was 4.8 nM, comparable to that obtained by LC with electrochemical detection combined with an enzyme reactor. In the online measurement of acetylcholine standard solutions, the sensitivity of the biosensor was 43.7 nA/pM at a flow rate of 16 pL/min. 

Acetylcholineesterase A stock solution of 0.52mg/mL of the pesticide trichlorophen in lOmM phosphate buffer of pH 7.5 was diluted with buffer to various concentrations. The obtained solutions were then analyzed using an ACh biosensor based on the inhibition effect of trichlorophen on the function AChE which promotes the hydrolysis of the natural neurotransmitter, acetylcholine. The sensor was fabricated by immobilizing AChE onto the surface of an antimony disc electrode, which was then used in conjunction with a double junction Ag/AgCl (0.1 M-KC1) reference electrode with a 0.1 M lithium acetate salt bridge. 

Nicotinic acetylcholine receptor The biosensors were constructed with poly (vinylbutyral) membranes incorporating nicotinic acetylcholine receptor for the determination of ACh. The detection range was 0.1-10 pM acetylcholine. [105]... 

Acetylcholineesterase and choline oxidase A glassy carbon electrode (GCE) modified by electrodepositing sub pm Pt-black particles on the surface. ACh and Ch. micro biosensor arrays were fabricated based on immobilization of AChE—ChO or ChO by cross linking with gentar-aldehyde on Pt-black GCE. Significant enhancement in the performance of these biosensors was achieved. The chronoamperometric response of 1 p biosensor array was linear from 29 to 1200 pM with detection limit of 8.7 pM acetylcholine. [109]... 

Karube and Yokoyama presented an overview on the developments in the biosensor technology [60]. The overview describes the use of micromachining fabrication techniques for the construction of detection units for FIA, electrochemical flow cells and chemiluminescence detectors. Acetylcholine microsensors using carbon fiber electrodes and glutamate microsensors for neuroscience were discussed. 

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