Electrochemically synthesized polyanine@Cu-BTC MOF as a bifunctional matrix for aptasensing of tetracycline in aquatic products

The development of new method for the rapid and facile screening of antibiotics residues in food is of great importance in food safety. Herein, a nanocompisite of polyaniline@copper-1,3,5-benzenetricarboxylic acid (PAN@Cu-BTC) with excellent electrochemical activity was directly prepared on the screen-printed electrode surface by a two-step electrochemical synthesis method. Then the tetracycline aptamer (TC-Apt) was assembled onto the electrode surface through the coordination between 5′-PO43- on the aptamer and Cu2+ on the MOF, achieving a novel electrochemical aptasensor for tetracycline (TC). The PAN@Cu-BTC has two functions in the aptasensors, namely the immobilization matrix of the aptamer probe and the internal signal source for target recognition. The electrochemical sensing assays showed that the capture of TC-Apt to the target on the electrode surface could cause the decrease of the electrochemical signal of PAN@Cu-BTC. Based on this, the TC can be analyzed in a wide range from 10 pM to 1 µM, with a low detection limit of 0.32 pM. The recoveries of the aptasensor for the detection of TC from Ctenopharyngodon idella meat were 90.0 %∼102.0 %, indicating that the constructed aptasensor is applicable for the detection of TC residues in fresh aquatic products.