title: Selective detection of hypertoxic organophosphates pesticides via PDMS composite based acetylcholinesterase-inhibition biosensor.
abstract: We report on a pair of highly sensitive amperometric biosensors for organophosphate pesticides (OPs) based on assembling acetylcholinesterase (AChE) on poly(dimethylsiloxane) (PDMS)-poly(diallydimethylemmonium) (PDDA)/gold nanoparticles (AuNPs) composite film. Two AChE immobilization strategies are proposed based on the composite film with hydrophobic and hydrophilic surface tailored by oxygen plasma. The twin biosensors show interesting different electrochemical performances. The hydrophobic surface based PDMS-PDDAN AuNPs/choline oxidase (ChO)/AChE biosensor (biosensor-1) shows excellent stability and unique selectivity to hypertoxic organophosphate. At optimal conditions, this biosensor-1 could measure 5.0 x 10(-10) g/L paraoxon and 1.0 x 10(-9) g/L parathion. As for the hydrophilic surface based biosensor (biosensor-2), it shows no selectivity but can be commonly used for the detection of most OPs. Based on the structure of AChE, it is assumed that via the hydrophobic interaction between enzyme molecules and hydrophobic surface, the enzyme active sites surrounded by hydrophobic amino acids face toward the surface and get better protection from OPs. This assumption may explain the different performances of the twin biosensors and especially the unique selectivity of biosensor-1 to hypertoxic OPs. Real sample detection was performed and the omethoate residue on Cottomrose Hibiscus leaves was detected with biosensor-1.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Ge
authors.forename: Jing-Juan
authors.initials: JJ
authors.lastname: Xu
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004784:Environmental Monitoring / Q000379:methods*; D004800:Enzymes, Immobilized; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D009943:Organophosphorus Compounds / Q000032:analysis* / Q000633:toxicity; D010575:Pesticides / Q000032:analysis* / Q000633:toxicity; D013054:Spectrophotometry, Atomic
chemical_list: D004129:Dimethylpolysiloxanes; D004800:Enzymes, Immobilized; D009943:Organophosphorus Compounds; D010575:Pesticides; C013830:baysilon; D000110:Acetylcholinesterase