An enzyme-free sensing platform based on molecularly imprinted polymer/MWCNT composite for sub-micromolar-level determination of pyruvic acid as a cancer biomarker.

Abstract

Pyruvic acid (PA) has been demonstrated to be an important cancer biomarker. Herein, carbon/carbon nanotube paste electrode was modified with the newly synthesized PA-imprinted polymer (MIP) and used as an enzyme-free sensor for PA assay. Methacrylic acid and ethylene glycol dimethacrylate were copolymerized in the presence of PA to prepare PA-IP. The MIP was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. To analyze PA by the MIP/CNT-CP electrode, the electrode was incubated in the PA solution for a constant time and then, the anodic differential pulse voltammetry signal was recorded. Both extraction and electrochemical determination solutions were the same, making the procedure simple and fast. Presence of the CNT in the MIP electrode led to a great enhancement in the PA signal. The MIP material not only pre-concentrated PA at the electrode surface but also increased the electron-exchange rate. This was confirmed by electrochemical impedance spectroscopy. The effects of electrode composition, extraction condition, and voltammetry parameters on the sensing efficiency were optimized. Dynamic linear range, detection limit, and RSD of the sensor were estimated to be 0.1-200μM, 0.048μM (S/N), and 3.6% (n = 3), respectively. The utility of the method was confirmed by appropriate analysis results obtained for the determination of PA in the plasma and urine samples. Graphical Abstract.