Li Na, Yuan Ruo, Chai Yaqin, Chen Shihong, An Haizhen
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, China.
Bioprocess Biosyst Eng. 2008 Oct;31(6):551-8. doi: 10.1007/s00449-008-0201-0. Epub 2008 Mar 7.
A novel amperometric immunosensor for human chorionic gonadotropin (HCG) assay has been fabricated through incorporating toluidine blue (TB) and hemoglobin (Hb) on the multiwall carbon nanotube (MWNT)-chitosan (CS) modified glassy carbon electrode, followed by electrostatic adsorption of a conducting gold nanoparticles (nanogold) film as sensing interface. The MWNT-CS matrix provided a congenial microenvironment for the immobilization of biomolecules and promoted the electron transfer to enhance the sensitivity of the immunosensor. Due to the strong electrocatalytic properties of Hb and MWNT toward H(2)O(2), the Hb and MWNT significantly amplified the current signal of the antigen-antibody reaction. The immobilized toluidine blue as an electron transfer mediator exhibited excellent electrochemical redox property. After the immunosensor was incubated with HCG solution, the access of activity center of the Hb to toluidine blue was partly inhibited, which leaded to a linear decrease in the catalytic efficiency of the Hb to the oxidation of immobilized toluidine blue by H(2)O(2) over HCG concentration ranges from 0.8 to 500 mIU/mL. Under optimal condition, the detection limit for the HCG immunoassay was 0.3 mIU/mL estimated at a signal-to-noise ratio of 3. Moreover, the proposed immunosensor displayed a satisfactory stability and reproducibility.
通过将甲苯胺蓝（TB）和血红蛋白（Hb）结合在多壁碳纳米管（MWNT）-壳聚糖（CS）修饰的玻碳电极上，随后静电吸附导电金纳米颗粒（纳米金）膜作为传感界面，制备了一种用于检测人绒毛膜促性腺激素（HCG）的新型安培免疫传感器。MWNT-CS基质为生物分子的固定提供了适宜的微环境，并促进了电子转移，从而提高了免疫传感器的灵敏度。由于Hb和MWNT对H₂O₂具有很强的电催化性能，Hb和MWNT显著放大了抗原-抗体反应的电流信号。固定化的甲苯胺蓝作为电子转移介质表现出优异的电化学氧化还原性能。免疫传感器与HCG溶液孵育后，Hb的活性中心与甲苯胺蓝的接触部分受到抑制，这导致在0.8至500 mIU/mL的HCG浓度范围内，Hb对H₂O₂氧化固定化甲苯胺蓝的催化效率呈线性下降。在最佳条件下，以3的信噪比估计，HCG免疫测定的检测限为0.3 mIU/mL。此外，所提出的免疫传感器表现出令人满意的稳定性和重现性。
