An ultrasensitive electrochemiluminescent aptasensor comprising mesoporous polydopamine covered with CdTe quantum dots for organophosphorus pesticide detection.

The development of sensitive devices for toxic organophosphorus pesticide detection is critical to monitor their environmental presence. In this study, we designed an ultrasensitive electrochemiluminescence-resonance energy transfer (ECL-RET) aptasensor sensing diazinon (DZN) with a limit of detection of only 0.42 fg/mL. The main component of our device was thioglycolic-acid-coated CdTe quantum dots anchored on a mesoporous polydopamine scaffold modified with poly (diallyl dimethylammonium) chloride (MPDAP-TCdTe QDs). This composite material was assembled to optimize the display of TCdTe QDs on a three-dimensional scaffold, which enhanced the ECL signal. The MPDAP-TCdTe QDs-based sensor was linear up to 106 fg/mL of DZN and exhibited a limit of quantification of 1.39 fg/mL. The ECL-RET device quantified DZN on vegetables and fruits with an accuracy above 95 % when considering relative errors. The sensor described in this work can detect ultra-low DZN concentrations and provide a methodological reference to ensure food and water safety.