Label free immunochromatographic sensor based on TCBPE for the detection of Acidovorax citrulli in Cucurbitaceae plants

The presence of Acidovorax citrulli (Ac), the etiological agent responsible for bacterial fruit blotch (BFB), exerts a profound impact on the growth and development of cucurbit plants. Therefore, it is imperative to promptly detect Ac to effectively mitigate the widespread dissemination of this disease among cucurbit crops. The present study describes the development of a novel label-free immunochromatographic strip (ICTS) sensor for the detection of Ac in cucurbit samples. This was achieved by utilizing 4’,4’’’,4’’’’’,4’’’’’’’-(ethene-1,1,2,2-tetrayl) tetrabiphenyl-4-carboxylic acid (TCBPE) carboxyl activation product (CA-TCBPE) as a fluorescent probe. The CA-TCBPE@Ac complex is captured at the detection site through the immobilization of a monoclonal antibody monoclonal antibody (mAb) targeting Ac in this sensor. Under the excitation of 365 nm ultraviolet (UV) light, the detection of Ac in the concentration range of 10 5 -10 8 CFU/mL was successfully achieved, with a visual detection limit of 10 5 CFU/mL. The accuracy of the sensor was further validated through experimentation with real samples, including watermelon, cantaloupe, cucumber, and zucchini. This study presents the pioneering development of a label-free ICTS sensor, utilizing TCBPE material markers, for rapid and sensitive detection of Ac. This innovative approach offers a robust solution for the swift detecting of Ac in cucurbits and other samples, thereby holding great promise for future applications.