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

Abstract 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. The MIP 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 × 10−8 M to 4 × 10−6 M for Tyr determination and a limit of detection (LOD) of 7.9 × 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.