An aptasensor consisting of the integrated MOF-derived Zn-MOF-on-Co-MOF coupled with AuNPs nanocomposites and aptamer for ultrasensitive assay of fipronil

The conductivity of Zn-MOF-on-Co-MOF synthesized by one-pot method is improved by searching for the optimum carbonization temperature, which overcomes the limitation of traditional MOF. In order to further enhance electron transfer, the mesoporous PtPdCo trimetal was introduced, which provided considerable load capacity for methylene blue (MB) and reverse complementary DNA (sDNA), and also showed excellent catalytic activity for MB. In this study, the conductivity of aptasensor was improved by modifying carbonized MOF as the base material. In the presence of fipronil (FIP), Apt tended to bind to FIP and was separated from the electrode surface, so that the remaining single-stranded complementary DNA (cDNA) were hybridized with signal probe (MB@PtPdCo/sDNA) and amplified the electrochemical signal. By modifying the substrate, competitive amplification strategy and signal probe material to catalyze signal molecules, the sensor performs multiple signal amplification, and the electrical signal is significantly improved. The sensor has a wide detection range 100 pg/mL to 100 μg/mL and a low detection limit of 76 pg/mL.