Diazinon electrochemical biosensor mediated by aptamer and nanoscale porous carbon derived from ZIF-8

The development of high-performance sensors for the assay of organophosphate pesticides (OPs) is of significant importance due to their broad usage and harmful effects on mammals. In this study, we designed a simple platform based on aptamer immobilized in an engineered zeolitic imidazolate framework (ZIF) for accurate detection of diazinon (DZN) as a widely used pesticide. To do so, aptamer-functionalized ZIF was constructed by using nanoscale porous carbon ZIF (NPCZIF) as scaffolds to load signal dye, methylene blue (MB), and capped with an aptamer as a bio-gatekeeper via π-π interaction. In this sensor, surface-covering aptamers prevented the release of MB. Therefore, the electrochemical signal of MB in the absence of DZN was low. Upon the addition of DZN, the configuration of the aptamer showed a change, resulting in a large number of MB labels being released from the pores. Therefore, the signal of MB increased. The proposed platform was highly sensitive toward DZN with a detection limit as low as 7.8 fM. The validation of the aptasensor was also studied by analyzing DZN in different food and environmental samples with recovery rates of 95.6–102.6%, indicating the feasibility and reliability of aptasensor.