A highly sensitive and rapid organophosphate biosensor based on enhancement of CdS - decorated graphene nanocomposite. Anal Chim Acta

Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China.
Analytica chimica acta (Impact Factor: 4.51). 06/2011; 695(1-2):84-8. DOI: 10.1016/j.aca.2011.03.042
Source: PubMed


This work reports a rapid and sensitive organophosphates (OPs) amperometric biosensor based on acetylcholinesterase (AChE) immobilized on CdS-decorated graphene (CdS-G) nanocomposite. The as-prepared biosensor shows high affinity to acetylthiocholine (ATCl) with a Michaelis-Menten constant (K(m)) value of 0.24 mM. A rapid inhibition time (2 min) is obtained due to the integration of the CdS-G nanocomposite. Based on the inhibition of OPs on the enzymatic activity of the immobilized AChE, and used carbaryl as the model compound, the resulting biosensor exhibits excellent performance for OPs detection including good reproducibility, acceptable stability, and a reliable linear relationship between the inhibition and log[carbaryl] from 2 ng mL⁻¹ up to 2 μg mL⁻¹ with a detection limit of 0.7 ng mL⁻¹,which provides a new promising tool for analysis of enzyme inhibitors.

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    • "These carbon nanotubes are highly conductive and have large surface area. Different supports used for immobilization of enzyme (Table 7) are AuNPs-CaCO3/Au electrode, Iron(Fe) NP/MWCNTs/Au electrode, FeNP/MWCNTs/indium tin oxide (ITO) electrode, AuNPs/PB/GCE [93], MWCNTs-Au nanocomposites/GCE [94], ZrO2/CHIT/GCE [95], Au-Pt bimetallic NPs/GCE [96], AuNPs/GCE [97], AuNPs-MWCNTs/GCE [98], PB/CHIT/GCE [99], TiO2 graphane/GCE [100], graphite-nanoplatelet CHIT composite/GCE [101], calcium carbonate-CHIT composite/GCE [102], CdS-decorated graphene nanocomposite [103], CHIT-GNPs/Au electrode [92], MWCNTs-CHIT/GCE [104], AuNPs/Au electrode [105], PbO2/TiO2/Ti [106], PB-CHIT/GCE [107], Er-GRO/Nafion [108], SWCNT modified FGE [109], Au-PtNPs/3-aminopropyltriethoxysilanes (APTEs)/GCE [110], CNT web modified GCE [111], PAN-AuNPs [112], CdTe AuNPs Film [113], and SiSG-AuNPs [114]. "
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    ABSTRACT: The exponentially growing population, with limited resources, has exerted an intense pressure on the agriculture sector. In order to achieve high productivity the use of pesticide has increased up to many folds. These pesticides contain organophosphorus (OP) toxic compounds which interfere with the proper functioning of enzyme acetylcholinesterase (AChE) and finally affect the central nervous system (CNS). So, there is a need for routine, continuous, on spot detection of OP compounds which are the main limitations associated with conventional analytical methods. AChE based enzymatic biosensors have been reported by researchers as the most promising tool for analysis of pesticide level to control toxicity and for environment conservation. The present review summarises AChE based biosensors by discussing their characteristic features in terms of fabrication, detection limit, linearity range, time of incubation, and storage stability. Use of nanoparticles in recently reported fabrication strategies has improved the efficiency of biosensors to a great extent making them more reliable and robust.
    Full-text · Article · Dec 2013 · Biochemistry Research International
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    ABSTRACT: CdS-reduced graphene oxide (RGO) composites are successfully synthesized via the microwave-assisted reduction of graphite oxide in a CdS precursor solution using a microwave synthesis system. The photocatalytic performances of CdS-RGO composites in the reduction of Cr(VI) are investigated. The results show that CdS-RGO composites exhibit enhanced photocatalytic performance for the reduction of Cr(VI) with a maximum removal rate of 92% under visible light irradiation as compared with pure CdS (79%) due to the increased light absorption intensity and the reduction of electron-hole pair recombination in CdS with the introduction of RGO.
    Full-text · Article · Sep 2011 · Chemical Communications
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    ABSTRACT: This report presents a highly sensitive, rhodamine B-covered gold nanoparticle (RB-AuNP) -based assay with dual readouts (colorimetric and fluorometric) for detecting organophosphorus and carbamate pesticides in complex solutions. The detection mechanism is based on the fact that these pesticides can inhibit the activity of acetylcholinesterase (AChE), thus preventing the generation of thiocholine (which turns the RB-AuNP solutions blue and unquenches the fluorescence of RB simultaneously). The color of the RB-AuNP solution remains red and the fluorescence of RB remains quenched. By use of this dual-readout assay, the lowest detectable concentrations for several kinds of pesticides including carbaryl, diazinon, malathion, and phorate were measured to be 0.1, 0.1, 0.3, and 1 μg/L, respectively, all of which are much lower than the maximum residue limits (MRL) as reported in the European Union pesticides database as well as those from the U.S. Department Agriculture (USDA). This assay allows detection of pesticides in real samples such as agricultural products and river water. The results in detecting pesticide residues collected from food samples via this method agree well with those from high-performance liquid chromatography (HPLC). This simple assay is therefore suitable for sensing pesticides in complex samples, especially in combination with other portable platforms.
    Full-text · Article · Apr 2012 · Analytical Chemistry
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