Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (19): 2085-2090.DOI: 10.6023/A12050257 Previous Articles     Next Articles

Full Papers


蒋姝婷a, 陈中平b, 刁奇智a, 盛尚春a, 谢国明a, 张名均b, 徐华建a   

  1. a 重庆医科大学检验医学院 临床检验诊断学教育部重点实验室 重庆 400016;
    b 重庆市九龙坡区第一人民医院 检验科 重庆 400050
  • 投稿日期:2012-05-30 发布日期:2012-07-30
  • 通讯作者: 谢国明
  • 基金资助:
    项目受重庆市自然科学基金(No. CSTC, 2010BB5356);重庆市九龙坡区科委科技项目(No. 2011009)和重庆医科大学临床检验诊断学国家重点学科基金(No. 2010102)资助.

Disposable Amperometric Immunosensor for Detecting Toxoplasma Gondii-Specific IgM Based on Graphene and CeO2-Au

Jiang Shutinga, Chen Zhongpingb, Diao Qizhia, Sheng Shangchuna, Xie Guominga, Zhang Mingjunb, Xu Huajiana   

  1. a Key Laboratory of Medical Diagnostics of Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China;
    b The First People’s Hospital of Jiulongpo District in Chongqing, Inspection Department, Chongqing 400050, China
  • Received:2012-05-30 Published:2012-07-30
  • Supported by:
    Project supported by the Natural Science Foundation of Chongqing (CSTC, 2010BB5356), The Science and Technology Project of Jiulongpo District Committee in Chongqing (2011009) and Foundation of National Key Discipline in Laboratory Medicine of Chongqing Medical University (2010102).

Toxoplasma gondii-specific IgM (Tg-IgM) is a sensitive and reliable marker for early diagnosing toxoplasmosis infection in pregnant women. In this study, a disposable amperometric immunosensor for sensitive detecting Tg-IgM was constructed based on graphene (GP) and CeO2-Au nanoparticle. The GP was treated with chitosan (CS) to obtain a stable graphene-chitosan (GPCS) composite membrane. The CeO2-Au nanoparticle which was used for the preparation of the amperometric immunosensor was synthesized by the hydrothermal method. GPCS composite membrane was first assembled onto the screen-printed carbon electrode (SPCE) for adsorbing the CeO2-Au nanoparticle. The toxoplasma gondii antigen (Tg-Ag) was subsequently adsorbed by CeO2-Au nanoparticle to obtain the proposed immunosensor. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to characterize the construction process of the immunosensor. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were used to study the electrochemical properties of the immunosensor. The results indicated that, CS employed in this study improved the dispersion and homogeneity of GP, as well as enhance the stability of the proposed immunosensor. The use of GPCS composite membrane and CeO2-Au nanoparticle had good conductivity and prominent biocompatibility, which excellently improved the sensitivity of the immunosensor. In the optimal conditions, the proposed immunosensor can be applied to quantify the concentration of Tg-IgM in a wide linear range from 7.5×10-4 AU·mL-1 to 24 AU·mL-1 with a correlation coefficient of -0.998 and a low detection limit of 4.4×10-4 AU·mL-1 (S/N=3). The novel proposed immunosensor for detecting Tg-IgM in human serum specimens with satisfactory results had also been proved. In addition, the Tg-IgM contents determined by the immunosensor agreed well with the ELISA measurement. Furthermore, the proposed amperometric immunosensor exhibited some advantages, such as high selectivity, long-term stability, good repeatability, low sample consumable, and short analysis time, which were suitable for detecting toxoplasma infection in pregnant women.

Key words: toxoplasma gondii-specific IgM, graphene, CeO2-Au, screen-printed carbon electrode, immunosensor