Polyaniline‐Mercaptobenzothiazole Biosensor for Organophosphate and Carbamate Pesticides

Abstract

Organophosphate and carbamate pesticides are powerful neurotoxins that impede the activity of cholinesterase enzyme leading to severe health effects. This study reports the development, characterization, and application of acetylcholinesterase (AChE) biosensors based on a gold electrode modified with mercaptobenzothiazole (MBT) self-assembled monolayer and either poly(o-methoxyaniline) (POMA) or poly(2,5-dimethoxyaniline) (PDMA) in the presence of polystyrene sulfonic acid (PSSA). The pesticide biosensors were applied in the aqueous phase detection of diazinon and carbofuran pesticides using Osteryoung square wave voltammetry (SWV) and differential pulse voltammetry (DPV) at low frequencies. The results of the study showed that up to 94% inhibition of the MBT-polyaniline-based biosensors can be achieved in sample solutions containing 1.19 ppb of these neurotoxin pesticide compounds. Both Au/MBT/PDMA-PSSA/AChE and Au/MBT/POMA-PSSA/AChE biosensors exhibited low detection limits, which were calculated using the percentage inhibition methodology. The Au/MBT/POMA-PSSA/AChE biosensor exhibited lower detection limits of 0.07 ppb for diazinon and 0.06 ppb for carbofuran than did the Au/MBT/PDMA-PSSA/AChE sensor system that had detection limits values of 0.14 ppb for diazinon and 0.11 ppb for carbofuran. The average sensitivity of the pesticide biosensor systems is 4.2 mA/ppb. A combination of the high sensor 1683 sensitivity and low detection limits means that it will be possible to deploy the polyaniline-based sensor systems as alarm devices for carbamate and organophosphate pesticides.

Electrochemical biosensor for pesticides based on acetylcholinesterase immobilized on polyaniline deposited on vertically assembled carbon nanotubes wrapped with ssDNA

“…The high specificity of biomolecules such as enzymes, receptors and antibodies allows for the assembly of the biosensors which can be used for a wide range of applications. Recently, acetylcholinesterase (AChE) enzyme based biosensors have attracted much attention due to their applications for the detection of anticholinesterase compounds or inhibitors including organophosphate and carbamate pesticides (Istamboulie et al, 2007;Castro et al, 2005;Lin et al, 2005;Schulze et al, 2005;Somerset et al, 2006). AChE belongs to the family of hydrolase characterized by a catalytic triad that is a coordinated structure consisting of three essential amino acids: histidine, serine and aspartic acid (Krasinski et al, 2005;Manetsch et al, 2004).…”

“…(Manisankar et al, 2005;Viswanathan et al, 2006;Wei and Ivaska, 2006). Polyaniline (PANI) an important conducting polymer is characterized by ease way of preparation, well-behaved electrochemistry, impressive signal amplification, and elimination of electrode fouling when used in biosensor applications (Somerset et al, 2006).…”

Biosensors based on cholinesterase inhibition for insecticides, nerve agents and aflatoxin B1 detection (review)

“…The affinity of thiols for some metal surfaces, particularly gold, makes alkanethiols ideal for the preparation of modified electrodes. Somerset et al have developed a gold electrode modified with mercaptobenzothiazole and either poly(o-methoxyaniline) or poly(2,5-dimethoxyaniline) [128,129]. An AChE based amperometric biosensor was developed by immobilisation of the enzyme onto a self assembled modified gold electrode using as 3-mercaptopropionic, glutaraldehyde and (N'-cyclohexy-N'-(2-morpholinoethyl) carbodiimide methyl-p-toluenesulfonate by Pedrosa et al [130,131].…”

Mercaptobenzothiazole-on-Gold Organic Phase Biosensor Systems: 3. Thick-Film Biosensors for Organophosphate and Carbamate Pesticide Determination

“…The resulting biosensor will be referred to as Au/MBT/PANI/AChE biosensor.For the Au/MBT/PANI/AChE bioelectrode, after enzyme incorporation the bioelectrode was arranged vertically and then coated with a 2 L drop of poly(vinyl acetate) (PVAc) solution (0.3 M) prepared in acetone and left to dry for 1 min. The resulting biosensor will be referred to as Au/MBT/PANI/AChE/PVAc biosensor (Somerset et al, 2006;Somerset et al, 2009). …”