A sandwich-type electrochemical immunosensor based on MnO2-Graphene quantum dots composites for detecting carcinoembryonic antigen.

• Main Authors: Meng-Shan Hsieh, 謝孟珊
• Other Authors: 蔡毓楨
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/8hk4ps

碩士 === 國立中興大學 === 化學工程學系所 === 106 === A novel nonenzymatic sandwich-type electrochemical innunosensor based on the manganese dioxide-graphene quantum dots (MnO2-GQDs) labeled secondary antibody was fabricated for detecting carcinoembryonic antigen (CEA). First, electrodeposition of gold nanoparticles (AuNPs) on screen printed carbon electrode (SPCE) that were used as electrochemical sensing platform improved the surface of electrode to immobilize first antibodies (Ab1) and enhanced the electrical conductivity. The synthetic MnO2-GQDs was used as labels of secondary antibodies (Ab2). By synergistically integrating highly catalytically activity of GQDs and MnO2, the composites possessed highly-efficient peroxidase-like catalytic activity which could produce a large current toward the reduction of H2O2 for signal amplification. MnO2-GQDs was applied as transducing materials to efficiently conjugate capture and amplify electrochemical signals. Under the optimal conditions, the proposed immunosensor was used for the detection of CEA with wide dynamic range from 0.003 to 50 ng·mL-1 and with a low detection limit of 1.02 pg·mL-1 Compared with traditional enzyme labels, the MnO2-GQDs based peroxidase mimetic system displayed an excellent analytical performance with low cost, satisfactory reproducibility and high selectivity, which could be further extended for detecting other disease-related biomarkers.