On the response of a label-free interferon-γ immunosensor utilizing electrochemical impedance spectroscopy
On the response of a label-free interferon-γ immunosensor utilizing electrochemical impedance spectroscopy
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DOI：
10.1016/j.bios.2004.10.009
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发表时间：
2005-07-15
影响因子：
12.6
通讯作者：
van Bennekom, WP
中科院分区：
文献类型：
--
作者：
Bart, M;Stigter, ECA;van Bennekom, WP
我们的干扰素-γ (IFN-gamma) 流动注射、无标记、非法拉第阻抗免疫传感器的研究得到了扩展。该传感器是通过将抗 IFN-γ 抗体固定在沉积在多晶金上的乙酰半胱氨酸自组装单层 (SAM) 上来制备的。描述了一种多频阻抗方法，该方法允许对奈奎斯特图进行时间分辨测量。对这些图拟合了等效电路，并根据界面区域的两层结构（内层和外层）进行讨论。由于 IFN-gamma 的结合主要导致 Q（恒定相位元素）降低，因此该元素被视为外层。研究了阻抗传感器响应的几个方面，包括对检测频率、目标浓度和施加的直流电势的依赖性。对于 IFN-γ 的定量检测，异相阻抗分量 (Z'') 的信噪比 (S/N) 最佳值约为 100 Hz。与饱和甘汞参比电极相比，在 +0.2 V 直流电势下，传感器响应高于 0.0 V 时的响应。使用两种程序获得浓度范围为 10(-18) 至 10(-9) M 的 IFN-gamma 对数剂量响应曲线：在单个电极上连续注射，以及每次测量使用新制备的电极。使用后一种方法，重复性会受到损害。讨论了正确解释所研究参数所需的原位补充技术。 (c) 2004 Elsevier B.V. 保留所有权利。
The research on our flow-injection, label-free, non-faradaic impedimetric immunosensor for interferon-gamma (IFN-gamma) has been extended. The sensor is prepared by immobilization of anti-IFN-gamma antibodies on a self-assembled monolayer (SAM) of acetylcysteine, deposited on polycrystalline gold. A multi-frequency impedance method is described, which allows time-resolved measurement of Nyquist plots. To these plots, an equivalent circuit was fitted, which is discussed in terms of a two-layer structure (inner and outer layer) of the interfacial region. Because binding of IFN-gamma mainly causes a decrease of Q (a constant-phase element), this element is considered as the outer layer.Several aspects of the impedimetric sensor response are studied, including the dependence on detection frequency, target concentration and applied dc potential. For quantitative detection of IFN-gamma, an optimum of the signal-to-noise (S/N) ratio of the out-of-phase impedance component (Z'') was found at about 100 Hz. At a dc-potential of +0.2 V versus a saturated calomel reference electrode, the sensor response is higher than at 0.0 V.Logarithmic dose-response curves of IFN-gamma in the concentration range of 10(-18) to 10(-9) M were obtained using two procedures: by successive injections over a single electrode, and by using freshly prepared electrodes for each measurement. Using the latter method, the repeatability is impaired. The need for in situ complementary techniques for a correct interpretation of the studied parameters is discussed. (c) 2004 Elsevier B.V. All rights reserved.