Ogi Hirotsugu, Motohisa Kazuma, Hatanaka Kenichi, Ohmori Toshinobu, Hirao Masahiko, Nishiyama Masayoshi
Graduate School of Engineering Science, Osaka University, Machikaneyama 1-3, Toyonaka, Osaka 560-8531, Japan.
Biosens Bioelectron. 2007 Jun 15;22(12):3238-42. doi: 10.1016/j.bios.2007.03.003. Epub 2007 Mar 12.
The binding affinity between human immunoglobulin G (IgG) and protein A was studied by the homebuilt wireless-electrodeless quartz crystal microbalance (QCM). Protein A was immobilized on the electrodeless AT-cut quartz plate of 0.05 mm thick and its fundamental resonance frequency near 34 MHz was measured by a noncontacting manner using a line antenna. The vibrational analysis was performed to ensure higher sensitivity of the electrodeless QCM. A flow-cell system was fabricated to continuously measure the resonance frequency during the injection sequence of the IgG solutions with concentrations of 1-20,000 ng/mL. The exponential frequency changes were recorded to determine the affinity based on the Langmuir kinetics. The equilibrium constant K(A) significantly varied between 6 x 10(6) and 6 x 10(10) M(-1), depending on the IgG concentration, which is attributed to various formations of IgG-protein A complexes.
采用自行搭建的无线无电极石英晶体微天平（QCM）研究了人免疫球蛋白G（IgG）与蛋白A之间的结合亲和力。将蛋白A固定在厚度为0.05 mm的无电极AT切石英板上，并使用线状天线以非接触方式测量其在34 MHz附近的基频共振频率。进行振动分析以确保无电极QCM具有更高的灵敏度。制作了流动池系统，以在注射浓度为1 - 20,000 ng/mL的IgG溶液序列期间连续测量共振频率。记录指数频率变化，以基于朗缪尔动力学确定亲和力。平衡常数K(A)在6×10⁶至6×10¹⁰ M⁻¹之间显著变化，这取决于IgG浓度，这归因于IgG - 蛋白A复合物的各种形成方式。
