title: Covalent fabrication of methyl parathion hydrolase on gold nanoparticles modified carbon substrates for designing a methyl parathion biosensor.
abstract: A biosensor based on AuNP modified GC electrodes has been developed for direct detection of methyl parathion. AuNP can be introduced to mixed monolayers of aryldiazonium salt modified GC electrodes by Au-C bonding through aryldiazonium salt chemistry, which provides a stable interface showing efficient electron transfer between biomolecules and electrodes. PEG molecules were introduced to the interface to resist non-specific protein adsorption. AuNP surfaces were further modified with 4-carboxyphenyl followed by covalent immobilization of methyl parathion hydrolase (MPH), a specific biocatalytic enzyme to methyl parathion. Exposure of this interface to methyl parathion resulted in a change in amperometric signal due to the MPH catalytic hydrolysis of methyl parathion producing electroactive compound 4-nitrophenol. This biosensor shows high selectivity, specificity, reproducibility and stability, and is functional for the detection of methyl parathion in real samples. The linear range for detection of methyl parathion is 0.2-100 ppb with a detection limit of 0.07 ppb in 0.1M phosphate buffer at pH 7.0.
authors.affiliation: Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China. Electronic address: gzliu@mail.ccnu.edu.cn.
authors.forename: Guozhen
authors.initials: G
authors.lastname: Liu
authors.forename: Wenqi
authors.initials: W
authors.lastname: Guo
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yin
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006867:Hydrolases / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D008743:Methyl Parathion / Q000737:chemistry / Q000302:isolation & purification*; D009596:Nitrophenols / Q000737:chemistry
chemical_list: D007306:Insecticides; D009596:Nitrophenols; D008743:Methyl Parathion; D002244:Carbon; D006046:Gold; D006867:Hydrolases; C024836:4-nitrophenol
keywords: Aryldiazonium salts; AuNP; Au–C bonding; Methyl parathion; Methyl parathion hydrolase