Capacitance measurements of antibody-antigen interactions in a flow system
Capacitance measurements of antibody-antigen interactions in a flow system
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DOI：
10.1021/ac970203e
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发表时间：
1997-09-15
影响因子：
7.4
通讯作者：
Johansson, G
中科院分区：
文献类型：
--
作者：
Berggren, C;Johansson, G
电容式免疫传感器是通过将单克隆抗体与硫辛酸偶联制成的，硫辛酸在金电极上自组装。未覆盖的表面区域用 1-十二烷硫醇堵塞，以使该层致密且绝缘。循环伏安法表明六氰基铁酸盐氧化还原反应被该过程阻断。根据施加恒电位步骤时获得的电流瞬变来评估电极的电容。将免疫传感器放置在现在的系统中，在注射未标记的抗原后可以观察到电容下降。当与抗原浓度的对数作图时，它在近三十年中呈线性。人绒毛膜促性腺激素的测定范围为1 pg/mL-1 ng/mL，检测限为0.5 pg/mL (15 10(-15) M)。使用固定的 F(ab')(2) 片段获得了类似的响应。与促甲状腺激素没有观察到交叉反应，促甲状腺激素与促性腺激素有一条共同链。固定在免疫传感器上的针对白细胞介素 2 的单克隆抗体也给出了超过 1 pg/mL-1 ng/mL 的响应，检测限为 1 pg/mL。具有针对人白蛋白的单克隆抗体的免疫传感器给出的校准曲线比其他蛋白质的斜率更低，但检测限仍然为 1 pg/mL。
Capacitive immunosensors were made by coupling monoclonal antibodies to thioctic acid, which had self-assembled on a gold electrode. Surface areas that were not covered were plugged with 1-dodecanethiol to make the layer dense and insulating. Cyclic voltammetry showed that the hexacyanoferrate redox reactions were blocked by this procedure. The capacitance of the electrode was evaluated from the current transients obtained when a potentiostatic step was applied. The immunosensor was placed in a now system, and a capacitance decrease could be observed after injection of an unlabeled antigen. It was linear over almost three decades when plotted vs the logarithm of the antigen concentration. Human chorionic gonadotropin hormone could be determined in the range 1 pg/mL-1 ng/mL, with a detection limit of 0.5 pg/mL (15 10(-15) M). A similar response was obtained with immobilized F(ab')(2) fragments. No cross-reactivity was observed with the thyrotropic hormone, which has one chain in common with gonadotropin. Monoclonal antibodies toward interleukin-2 immobilized on the immunosensor gave also a response over 1 pg/mL-1 ng/mL, with a detection limit of 1 pg/mL. An immunosensor with monoclonal antibodies toward human albumin gave a calibration curve with lower slope than the other proteins but still with a detection limit of 1 pg/mL.