Immunochromatographic Assay based on Sc-TCPP 3D MOF for the rapid detection of imidacloprid in food samples.

• The Sc nanocubes based immunoassay was developed for detection of imidacloprid. • The Sc nanocubes had large surface area, remarkable intensity and biocompatibility. • The sensor had a low limit of detection and specificity for imidacloprid detection. • Satisfactory analytical results in real samples suggested the sensor's applicability. In this work, a highly sensitive immunochromatographic test strip (ITS) based on Scandium-Tetrakis (4-carboxyphenyl) porphyrin (TCPP) metal–organic framework nanocubes (ScTMNs) was developed for ultrasensitive and facile visual determination of imidacloprid (IDP). TCPP as the porphyrin-based planar ligand and Sc3+ as the metal center were applied to form the ScTMNs via coordination chelation. Giving the credit to its excellent optical characteristics, strong affinity with monoclonal antibodies, and favorable biocompatibility, the ScTMNs was selected as a signal tag. Under optimized conditions, the ITS exhibited a great liner relationship in the range of 0.04–3 ng/mL and the detection limit was 0.04 ng/mL for the IDP detection. Additionally, IDP was successfully detected in tomatoes, millet, corn and carrot samples with satisfied recoveries. To the best of our knowledge, this is the first time that ScTMNs have been used in immunochromatography which are expected to have potential applications in detection of other substances. [ABSTRACT FROM AUTHOR]