Rapid fabrication of electrode for the detection of alpha fetoprotein based on MnO₂ functionalized mesoporous carbon...

The concentration of alpha-fetoprotein (AFP) rises greatly in patients with liver cancer and it is a challenge to construct a sensitive AFP detection method with wide range. Therefore, an easy and label-free sensing electrochemical platform for AFP detection with wide concentration range had been designed in this work. Firstly, MnO₂ functionalized mesoporous carbon hollow sphere (MCHS@MnO₂) with optimal performance was synthesized by regulating experimental conditions and characterized by scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), etc. Then, it was immobilized on glassy carbon electrode (MCHS@MnO₂/GCE) to build an immunosensor for the detection of AFP. The MCHS@MnO₂/GCE can catalyze decomposition of H₂O₂ to generate electrochemical signal, and the signal will decrease after capturing AFP. Due to good electrocatalytic activity of MCHS@MnO₂ to H₂O₂, the immunosensor achieved indirect detection of AFP with wide sensing range from 0.10 ng mL^-1 to 420 ng mL^-1 and a detection limit of 0.03 ng mL^-1. Furthermore, the method had been proven to be satisfactory selectivity and reproducibility, and it was successfully applied to determine the content of AFP in human serum samples with satisfactory results. This method is expected to be used for early diagnosis and prognosis examination of liver cancer patients.