title: Ultra-sensitive biosensor based on mesocellular silica foam for organophosphorous pesticide detection.
abstract: A sensitive amperometric acetylcholinesterase (AChE) biosensor was fabricated based on mesocellular silica foam (MSF), which functioned as both an enzyme immobilization matrix and a solid phase extraction (SPE) material for the preconcentration of target molecules. The hydrophilic interface, the good mechanical/chemical stability, and the suitable pore dimension of MSF provided the entrapped AChE a good environment to well maintain its bioactivity at basic condition. The AChE immobilized in MSF showed improved catalytic ability for the hydrolysis of acetylthiocholine, as evidenced by the increasing of the oxidation current of thiocholine, the enzymatic catalytic hydrolysis production of acetylthiocholine. In addition, the MSF with large surface area showed a modest adsorption capacity for monocrotophos, a model organophosphate used in this study, via the hydrogen bond or physical adsorption interaction. The combination of the SPE and the good enzyme immobilization ability in MSF significantly promoted the sensitivity of the biosensor, and the limit of detection has lowered to 0.05 ng/mL. The biosensor exhibited accuracy, good reproducibility, and acceptable stability when used for garlic samples analysis. The strategy may provide a new method to fabricate highly sensitive biosensors for the detection of ultra-trace organophosphorous pesticide infield.
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China. wushuo@dlut.edu.cn
authors.forename: Shuo
authors.initials: S
authors.lastname: Wu
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Qi
authors.forename: Shengyang
authors.initials: S
authors.lastname: Tao
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Lan
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Liu
authors.forename: Changgong
authors.initials: C
authors.lastname: Meng
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000122:Acetylthiocholine / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D004800:Enzymes, Immobilized / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis; D005737:Garlic / Q000737:chemistry; D008999:Monocrotophos / Q000032:analysis; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D012822:Silicon Dioxide
chemical_list: D004800:Enzymes, Immobilized; D009943:Organophosphorus Compounds; D010575:Pesticides; D000122:Acetylthiocholine; D008999:Monocrotophos; D012822:Silicon Dioxide; D000110:Acetylcholinesterase