BIOSYST-MeBioS, Katholieke Universiteit Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium.
Biosens Bioelectron. 2011 Feb 15;26(6):2987-93. doi: 10.1016/j.bios.2010.11.053. Epub 2010 Dec 5.
Like antibodies, aptamers are highly valuable as bioreceptor molecules for protein biomarkers because of their excellent selectivity, specificity and stability. The integration of aptamers with semiconducting materials offers great potential for the development of reliable aptasensors. In this paper we present an aptamer-based impedimetric biosensor using a nanocrystalline diamond (NCD) film as a working electrode for the direct and label-free detection of human immunoglobulin E (IgE). Amino (NH(2))-terminated IgE aptamers were covalently attached to carboxyl (COOH)-modified NCD surfaces using carbodiimide chemistry. Electrochemical impedance spectroscopy (EIS) was applied to measure the changes in interfacial electrical properties that arise when the aptamer-functionalized diamond surface was exposed to IgE solutions. During incubation, the formation of aptamer-IgE complexes caused a significant change in the capacitance of the double-layer, in good correspondence with the IgE concentration. The linear dynamic range of IgE detection was from 0.03 μg/mL to 42.8 μg/mL. The detection limit of the aptasensor reached physiologically relevant concentrations (0.03 μg/mL). The NCD-based aptasensor was demonstrated to be highly selective even in the presence of a large excess of IgG. In addition, the aptasensor provided reproducible signals during six regeneration cycles. The impedimetric aptasensor was successfully tested on human serum samples, which opens up the potential of using EIS for direct and label-free detection of IgE levels in blood serum.
与抗体类似，适体作为蛋白质生物标志物的生物受体分子非常有价值，因为它们具有出色的选择性、特异性和稳定性。适体与半导体材料的结合为可靠的适体传感器的发展提供了巨大的潜力。在本文中，我们提出了一种基于适体的阻抗生物传感器，使用纳米晶金刚石（NCD）薄膜作为工作电极，用于直接和无标记检测人免疫球蛋白 E（IgE）。使用碳化二亚胺化学将氨（NH2）-末端 IgE 适体共价连接到羧基（COOH）修饰的 NCD 表面。电化学阻抗谱（EIS）用于测量当适体功能化的金刚石表面暴露于 IgE 溶液时界面电性质的变化。在孵育过程中，适体-IgE 复合物的形成导致双层电容发生显著变化，与 IgE 浓度具有良好的对应关系。IgE 检测的线性动态范围为 0.03 μg/mL 至 42.8 μg/mL。该适体传感器的检测限达到了生理相关的浓度（0.03 μg/mL）。即使存在大量 IgG 过剩，NCD 基适体传感器也表现出高度的选择性。此外，该适体传感器在六个再生循环中提供了可重复的信号。阻抗适体传感器已成功应用于人血清样本的测试，这为使用 EIS 直接和无标记检测血清中的 IgE 水平开辟了潜力。
