Au nanoparticles @metal organic framework/polythionine loaded with molecularly imprinted polymer sensor: Preparation, characterization, and electrochemical detection of tyrosine

In this study, a new dual-signal electrochemical sensor using a glassy carbon electrode (GCE) modified with molecularly imprinted polyaniline/polythionine/gold nanoparticles@zeolitic imidazolate framework-67 composite (MIP/ pTH/Au@ZIF-67) is fabricated for the quantitative analysis of tyrosine (Tyr). Au@ZIF-67 is used as a matrix to improve the surface area and electron-transfer ability of the sensor. The pTH as a built-in probe provides a signal-off response, meanwhile the oxide current of Tyr acts as a signal-on response. TheMIP is prepared in the presence of aniline monomer and Tyr template by electro-polymerization for Tyr specific recognition. Under the optimized conditions, the sensor demonstrates a linear range from 1 x 10(-8) M to 4 x 10(-6) M for Tyr determination and a limit of detection (LOD) of 7.9 x 10(-10) M (S/N = 3). Furthermore, the sensor exhibits excellent selectivity, superior stability and good reproducibility toward Tyr. More importantly, the sensor is successfully employed to detect Tyr in human serum with satisfactory recoveries. (C) 2020 Elsevier B.V. All rights reserved.