Zhang Qundan, Huang Yanyan, Zhao Rui, Liu Guoquan, Chen Yi
Beijing National Laboratory for Molecular Sciences, Laboratory of Analytical Chemistry for Life Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
J Colloid Interface Sci. 2008 Mar 1;319(1):94-9. doi: 10.1016/j.jcis.2007.11.039. Epub 2007 Nov 29.
A novel biosensor for detecting antithrombin III (AT III) was constructed based on in situ growth of nanogold on the gold electrode of quartz crystal microbalance (QCM). The growth process of nanogold was monitored by QCM in real time. Heparin was used as the affinity ligand and immobilized onto the nanogold modified gold electrode. A flow injection analysis-quartz crystal microbalance (FIA-QCM) system was used to investigate the relationship between nanogold growth and the AT III response. Along with the nanogold particle growth within initial 5 min, the amount of heparin immobilized onto the nanogold modified electrode increased quickly. Correspondingly, the frequency response to AT III binding increased rapidly at the same time. After that, both the immobilized amount of heparin and the sensor response to AT III decreased gradually. Compared with the directly immobilized large nanogold particles, the in situ grown particles with the same size occupy more sensor surface, resulting in higher frequency shifts to AT III in the interaction study between heparin and AT III. The obtained constants of AT III binding to immobilized heparin are k(ass)=(1.65+/-0.12)x10(3) L/mols, k diss=(2.63+/-0.18)x10(-2) 1/s and K(A)=(6.27+/-0.42)x10(4) L/mol.
基于纳米金在石英晶体微天平（QCM）金电极上的原位生长，构建了一种用于检测抗凝血酶III（AT III）的新型生物传感器。纳米金的生长过程由QCM实时监测。肝素用作亲和配体并固定在纳米金修饰的金电极上。采用流动注射分析-石英晶体微天平（FIA-QCM）系统研究纳米金生长与AT III响应之间的关系。在最初的5分钟内，随着纳米金颗粒的生长，固定在纳米金修饰电极上的肝素量迅速增加。相应地，对AT III结合反应的频率响应同时迅速增加。之后，肝素的固定量和传感器对AT III的响应均逐渐降低。与直接固定的大尺寸纳米金颗粒相比，相同尺寸的原位生长颗粒占据更多的传感器表面，在肝素与AT III的相互作用研究中导致对AT III的频率偏移更高。获得的AT III与固定化肝素结合的常数为：结合速率常数k(ass)=(1.65±0.12)x10(3) L/mol·s，解离速率常数k diss=(2.63±0.18)x10(-2) 1/s，亲和常数K(A)=(6.27±0.42)x10(4) L/mol。
