Monospecific, ultrasensitive, and quantitative lateral flow immunoassay for dibutyl phthalate via epitopes rational design strategies

Due to the characteristics of long-term persistence, leading to extensive temporal and spatial distribution of the environmental pollutant dibutyl phthalate (DBP), analyzing of a large number of food and environment samples over a long period and at a high frequency must be necessary. It is of great significance to construct a simple, rapid, sensitive and high-throughput immunoassay method. For the first time, 8 different DBP hapten molecules were designed using computer simulation to provide DBP epitope informations from both conformation and electrostatic aspects for the target molecule. This approach helped to establish a reasonable hapten design strategy while reducing the cost and increasing the success rate of producing the required high-specificity and high-sensitivity DBP antibodies. Hapten DBP-1 was proposed, and the effectiveness of computer-aided hapten DBP-1 design was further verified by mouse antiserum experiments. A highly-specific monoclonal antibody (mAb) against DBP with an IC₅₀ value of 19.8 ng/mL was obtained by mAb screening with enhanced matrix effect. A colloidal gold immunochromatographic test strip (CIS) which can be used to detect DBP in environmental, food and human urine samples was further prepared, and the DBP content in positive samples such as water, soil, and liquor samples could be rapidly analyzed within 15 min, which were basically consistent with the data by Gas Chromatography-Mass Spectrometry (GC-MS). In summary, our study proposed a detection method that can be directly used to detect DBP in environmental water, soil, liquor and human urine samples, which is ready for application in environmental monitoring, food safety control and clinical use.