A highly sensitive and rapid organophosphate biosensor based on enhancement of CdS-decorated graphene nanocomposite.
ABSTRACT 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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ABSTRACT: Silica nanosheets were prepared from montmorillonite and carboxyl functionalized by a chemical method. Platinum nanoparticles (Pt NPs) were also synthesized on carboxylic silica nanosheets (CSNSs). An acetylcholinesterase (AChE) biosensor based on a Pt NP, CSNS, and Nafion nanocomposite-modified glass carbon electrode was successfully developed. The AChE biosensor showed favorable affinity to acetylthiocholine chloride (ATCl) and catalyzed the hydrolysis of ATCl with an apparent Michaelis-Menten constant value of 125 μM. Under optimal conditions, the biosensor detected methyl parathion and carbaryl in the range of 1.0 × 10−12 M to 1 × 10−8 M. The detection limits for methyl parathion and carbaryl were 5.52 × 10−13 and 5.65 × 10−13 M, respectively. The developed biosensor was inexpensive and exhibited good sensitivity, stability, and reproducibility, thus providing a promising tool for the analysis of enzyme inhibitors. A simple and effective immobilization platform was also provided for effectively immobilizing the enzyme on the electrode surface.Analytical methods 01/2014; 6(6):1914. DOI:10.1039/c3ay42305k · 1.94 Impact Factor
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