Development of an enzyme-linked immunosorbent assay for thiacloprid in soil and agro-products with phage-displayed peptide.

A monoclonal antibody (3A5) that can recognize thiacloprid was produced, and a linear 8-residue peptide phage library was constructed. Six phage-displayed peptides were isolated from the linear 8-residue peptide phage library and a cyclic 8-residue peptide phage library. A phage enzyme-linked immunosorbent assay (ELISA) was developed to detect thiacloprid using a phage-displayed peptide. Under the optimal conditions, the half-maximal inhibition concentration (IC50) and the limit of detection (IC10) of the developed phage ELISA were 8.3 and 0.7 µg/L, respectively. Compared with the conventional ELISA, the sensitivity was improved more than 3-fold. The cross-reactivity (CR) was less than 0.08% for the tested structural analogues and was regarded as negligible. The recoveries of thiacloprid ranged from 80.3% to 116.3% in environmental and agricultural samples, which conformed to the requirements for residue detection. The amount of thiacloprid detected by phage ELISA in the samples was significantly correlated with that detected by high-performance liquid chromatography. The current study indicates that isolating phage-displayed peptides from phage display libraries is an alternative method for the development of a sensitive immunoassay and that the developed assay is a potentially useful tool for detecting thiacloprid in environmental and agricultural samples.

Development of a monoclonal antibody-based enzyme-linked immunosorbent assay for tetrabromobisphenol A.

Tetrabromobisphenol A (TBBPA) has been an important brominated flame retardant worldwide and has become a widely concerned environmental pollutant due to its persistence in the environment. In this study, a monoclonal antibody (MAb, designated 3D9G6) against TBBPA was produced, and an indirect competitive enzyme-linked immunoassay (icELISA) for detecting trace TBBPA was developed. The limit of detection and the half maximum inhibition concentration of TBBPA in phosphate-buffered saline were 0.8 and 3.87 ng·mL(-1), respectively. The assay specificity was studied with TBBPA structural analogs, such as bisphenol A, decabromodiphenyl ether, octabromobisphenol-S, and hexabromocyclododecane, and the results showed that none of these can be recognized by the MAb even at a concentration of up to 4000 ng·mL(-1). The average recoveries of TBBPA in water and soil samples were 96% and 87%, respectively. This icELISA can be applied for the detection of trace levels of TBBPA in water and soil samples.

Development of antibody-labelled superparamagnetic nanoparticles for the visualisation of benzo[a]pyrene in porous media with magnetic resonance imaging.

Biogeochemical interfaces in soil are dynamic in the spatial and temporal domain and require advanced visualisation and quantification tools to link in vitro experiments with natural systems. This study presents the development, characterization and application of functional nanoparticles coated with monoclonal antibodies to visualise the distribution of benzo[a]pyrene in porous media using magnetic resonance imaging. The labelled particles are 450 nm in diameter and interact with benzo[a]pyrene covalently bound to silanized silica gel. They did not bind to benzo[a]pyrene adsorbed to plain silica gel. Although unspecific filtration was low, washing steps are required for visualisation. The ability to visualise benzo[a]pyrene is inversely correlated to the heterogeneity of the soil materials. There are access restrictions to narrow pore spaces which allow the visualisation of only those pathways which are also accessible to bacteria and hydrocolloids. The production of the particles is applicable to other antibodies which extends the range of potential target contaminants.

Production of monoclonal antibody to herbicide fenoxaprop-ethyl.

Fenoxaprop-ethyl is a selective aryloxyphenoxypropionate herbicide used widely to control annual and perennial grasses. A monoclonal antibody (MAb) against fenoxaprop-ethyl (FE), designated as 3E6B9C, was produced and had very low cross-reactivity with some of its structural analogs, such as clodinafop-propargyl, diclofop-methyl, lactofen, and quizalofop-p-ethyl. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed. The concentration of R-(+)-fenoxaprop-ethyl (R-FE) producing 50% of inhibition (IC(50)) and the working range of icELISA were 3.1 ng/mL and 0.6-29 ng/mL, respectively. This assay is also sensitive to R-fenoxaprop, S-(-)-fenoxaprop-ethyl, and metamifop with IC(50) of 3.4, 2.7, and 3.5 ng/mL, respectively. The recoveries of R-FE in soil samples with the icELISA were 86-102%.

Characterization and performance evaluation of in vivo and in vitro produced monoclonal anti-TNT antibodies for the detection of TNT.

In this paper are the experimental results used to characterize four distinct monoclonal anti-TNT antibodies (in vivo and in vitro cloned) for potential use in a field-portable immunosensor. Direct and competitive enzyme-linked immunosorbent assays (ELISA) were performed to determine their affinity for TNT and a fluorescently labeled analog of TNT for use in an immunosensor. Effective concentrations (EC(50)), inhibition concentration (IC(50)) and cross-reactivity measurements to related nitroaromatics (e.g., 2,4,6-trinitrobenzene [TNB], methyl-2,4,6-trinitrophenyl nitramine [tetryl], 2-amino-4,6-dinitrotoluene [2A-4,6-DNT], 2,4-dinitrotoluene [2,4-DNT] and 1,3-dinitrotoluene [1,3-DNT]) were measured. Final characterization of the monoclonal antibodies was based on performance (measured by fluorescence dose response) using a fluorescence-based microcapillary displacement assay. Analytical techniques showed a high degree of affinity for TNT and varying degrees of cross-reactivity with each respective monoclonal antibody. Microcapillary displacement immunoassays with each of the antibodies resulted in detection capabilities at the lowest applied TNT concentration (10 ng/ml).