Abstract
A novel detection method of small molecules, competitive bio-barcode amplification immunoassay, was developed and described in this report. Through the gold nanoparticles (AuNPs) probe and magnetic nanoparticles (MNPs) probe we prepared, only one monoclonal antibody can be used to detect small molecules. The competitive bio-barcode amplification immunoassay overcomes the obstacle that the bio-barcode assay cannot be used in small molecular detection, as two antibodies are unable to combine to one small molecule due to its small molecular structure. The small molecular compounds, triazophos, were selected as targets for the competitive bio-barcode amplification immunoassay. The linear range of detection was from 0.04 ng mL−1 to 10 ng mL−1, and the limit of detection (LOD) was 0.02 ng mL−1, which was 10–20 folds lower than ELISA (Enzyme Linked Immunosorbent Assay). A practical application of the proposed immunoassay was evaluated by detecting triazophos in real samples. The recovery rate ranged from 72.5% to 110.5%, and the RSD was less than 20%. These results were validated by GC-MS, which indicated that this convenient and sensitive method has great potential for small molecular in real samples.
Highlights
Immunological assays have the characteristics of specificity, sensitivity and ease of handling, which has been widely used compared with other detection methods
In order to test the application of the newly development competitive bio-barcode amplification immunoassay method in small molecule detection, we constructed the competitive bio-barcode amplification immunoassay for triazophos, a broad-spectrum organophosphorus insecticide applied for pest control in rice paddies
In this study, we present the first example of small molecule detection with a competitive bio-barcode amplification immunoassay based on nanoparticles and real-time polymerase chain reaction (PCR)
Summary
Immunological assays have the characteristics of specificity, sensitivity and ease of handling, which has been widely used compared with other detection methods. Mirkin et al.[11] established a bio-barcode assay to quantify prostate-specific antigen (PSA) based on nanoparticles. The sensitivity of this method was higher than accepted conventional assays for detecting the same target. Mirkin et al developed a fluorophore-based bio-barcode amplification assay for proteins. This method is more sensitive than immuno-PCR for the systems studied far, does not rely on enzymatic amplification, and is less complex[18]. In this study, we present the first example of small molecule detection with a competitive bio-barcode amplification immunoassay based on nanoparticles and real-time PCR. A magnetic nanoparticles (MNPs) probe was developed by combining magnetic nanoparticles and ovalbumin (OVA) coupled with the small molecules hapten
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