Liang Wenbin, Yi Weijing, Li Shuhui, Yuan Ruo, Chen An, Chen Sha, Xiang Guiming, Hu Chuanmin
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, PR China.
Clin Biochem. 2009 Oct;42(15):1524-30. doi: 10.1016/j.clinbiochem.2009.07.009. Epub 2009 Jul 17.
Novel immunoassay methods based on electrochemical sensors have been developed, but most of these immunosensors are unsuitable for clinical detection because their preparation requires complicated chemical procedures and because their detection sensitivity is restricted. In order to develop a highly sensitive, label-free amperometric sensor for immunoassays, we synthesised novel, functionalized gold nanoparticles (SV-GNP) by covalently capping the surface of gold nanoparticles (GNP) with 1,1'-bis-(2-mercapto)-4,4'-bipyridinium dibromide, a kind of sulfhyrdryl viologen (SV).
We fabricated an immunosensor in a multi-step fashion, by first coating the SV-GNP onto a glassy carbon electrode surface; the resulting electrode core could then adsorb a suitable antibody in a second step to afford the desired immunosensor. alpha-fetoprotein (AFP) was used as a model analyte in this work.
The anti-AFP/SV-GNP-modified electrode was sensitive to AFP with a linear relationship between 1.25 and 200 ng/mL and a correlation coefficient of 0.9983; the detection limit at a signal to noise ratio of 3 was 0.23 ng/mL under optimal conditions. In addition, the proposed immunosensor exhibited good sensitivity, selectivity, stability and long-term maintenance of bioactivity.
The described immunosensor preparation and immunoassay methods offer promise for label-free, simple, and cost-effective analysis of biological samples.
基于电化学传感器的新型免疫分析方法已被开发出来，但这些免疫传感器大多不适用于临床检测，因为其制备需要复杂的化学程序，且检测灵敏度受限。为了开发一种用于免疫分析的高灵敏度、无标记安培传感器，我们通过用一种巯基紫精（SV），即1,1'-双（2-巯基）-4,4'-联吡啶二溴化物共价包覆金纳米颗粒（GNP）的表面，合成了新型功能化金纳米颗粒（SV-GNP）。
我们分多步制造了一种免疫传感器，首先将SV-GNP涂覆在玻碳电极表面；在第二步中，所得的电极核心可以吸附合适的抗体，从而得到所需的免疫传感器。在这项工作中，甲胎蛋白（AFP）用作模型分析物。
抗AFP/SV-GNP修饰电极对AFP敏感，在1.25至200 ng/mL之间呈线性关系，相关系数为0.9983；在最佳条件下，信噪比为3时的检测限为0.23 ng/mL。此外，所提出的免疫传感器表现出良好的灵敏度、选择性、稳定性和生物活性的长期维持。
所描述的免疫传感器制备和免疫分析方法为生物样品的无标记、简单且经济高效的分析提供了前景。
