title: A bare-eye based one-step signal amplified semiquantitative immunochromatographic assay for the detection of imidacloprid in Chinese cabbage samples.
abstract: A novel bare-eye based one-step signal amplified semi-quantitative immunochromatographic assay (SAS-ICA) was developed for detection of the pesticide imidacloprid. This method was based on competitive immunoreactions. Signal amplification was achieved by dual labeling of the test lines (TLs) on the strip using high affinity nanogold-biotinylated anti-imidacloprid mAb (BAb) and nanogold-streptavidin (Sa) probes. The relative color intensities of three TLs (TL-I, TL-II and TL-III) on a nitrocellulose (NC) membrane were used for direct visual analysis of the SAS-ICA strips, and could be used for semi-quantitation of analyte concentrations by observing what TLs disappeared in the amplification zone. Under optimized conditions, the following imidacloprid concentration ranges would be detected by visual examination of the SAS-ICA strip: 0-5ngmL(-1) (negative samples), and 5-25ngmL(-1), 25-250ngmL(-1), 250-1000ngmL(-1) and >1000ngmL(-1) (positive samples). The sensitivity (the visual detection limit (VDL) of TL-III) and semi-quantitative analytical capacity (when TL-III disappeared completely) of the SAS-ICA strip were 10-fold and 160-fold higher than those of traditional ICA, respectively. The developed SAS-ICA strip was applied to the analysis of spiked and authentic contaminated Chinese cabbage samples in the laboratory and under field conditions, and the results were validated by high-performance liquid chromatography (HPLC). This process could be adopted as a potential generous technique for all ICA-based detection methods.
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Qingkui
authors.initials: Q
authors.lastname: Fang
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Limin
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Cai
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Yang
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xiude
authors.initials: X
authors.lastname: Hua
authors.affiliation: College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, PR China; Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, PR China. Electronic address: fqliu20011@sina.com.
authors.forename: Fengquan
authors.initials: F
authors.lastname: Liu
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D001937:Brassica / Q000737:chemistry*; D002846:Chromatography, Affinity / Q000295:instrumentation / Q000379:methods*; D003101:Collodion / Q000737:chemistry; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D007093:Imidazoles / Q000032:analysis*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D011934:Reagent Strips; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues; D011934:Reagent Strips; C082359:imidacloprid; D001710:Biotin; D006046:Gold; D003101:Collodion; D019809:Streptavidin
keywords: Bare-eye based semi-quantitative; Chinese cabbage; Imidacloprid; Immunochromatographic assay; Signal amplification