title: Ultrasensitive detection of deltamethrin by immune magnetic nanoparticles separation coupled with surface plasmon resonance sensor.
abstract: Small molecules or analytes present in trace level are difficult to be detected directly using conventional surface plasmon resonance (SPR) sensor, due to its small changes in the refractive index induced by the binding of these analytes on the sensor surface. In this paper, a new approach that combines SPR sensor technology with Fe3O4 magnetic nanoparticles (MNPs) assays is developed for directly detecting of deltamethrin in soybean. The Fe3O4 MNPs conjugated with antibodies specific to antigen serves as both labels for enhancing refractive index change due to the capture of target analyte, and "vehicles" for the rapid delivery of analyte from a sample solution to the sensor surface. Meanwhile, SPR direct detection format without Fe3O4 MNPs and gas chromatography (GC) analysis were conducted for detection of deltamethrin in soybean to demonstrate the amplification effect of Fe3O4 MNPs. A good linear relationship was obtained between SPR responses and deltamethrin concentrations over a range of 0.01-1 ng/mL with the lowest measurable concentration of 0.01 ng/mL. The results reveal that the detection sensitivity for deltamethrin was improved by 4 orders of magnitude compared with SPR direct detection format. The recovery of 95.5-119.8% was obtained in soybean. The excellent selectivity of the present biosensor is also confirmed by two kinds of pesticides (fenvalerate and atrazine) as controls. This magnetic separation and amplification strategy has great potential for detection of other small analytes in trace level concentration, with high selectivity and sensitivity by altering the target-analyte-capture agent labeled to the carboxyl-coated Fe3O4 MNPs.
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China; State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, PR China. Electronic address: liuxiaspr@gmail.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: You-Qian
authors.initials: YQ
authors.lastname: Liu
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: Xing-Bo
authors.initials: XB
authors.lastname: Shi
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: Wen-Jin
authors.initials: WJ
authors.lastname: Li
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Food Science and Technology, Hunan Agricultural University, Hunan Province Key Laboratory of Food Science and Biotechnology, Changsha 410128, PR China.
authors.forename: Lu-Gang
authors.initials: LG
authors.lastname: Mao
mesh_terms: D007306:Insecticides / Q000032:analysis*; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D009570:Nitriles / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis*; D013025:Glycine max / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D007306:Insecticides; D058185:Magnetite Nanoparticles; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin
keywords: Deltamethrin detection; Fe(3)O(4) magnetic nanoparticles; Surface plasmon resonance sensor