Department of Biophysics , Ruhr-Universität Bochum , Universitätsstrasse 150 , D-44801 Bochum , Germany.
Center for Protein Diagnostics (ProDi) , Gesundheitscampus 4 , 44801 Bochum , Germany.
ACS Sens. 2019 Jul 26;4(7):1851-1856. doi: 10.1021/acssensors.9b00631. Epub 2019 Jul 10.
The development of biosensors for medical purposes is a growing field. An immuno-infrared biosensor for the preclinical detection of Alzheimer's disease (AD) in body fluids was developed. The key element of this sensor is an ATR crystal with chemically modified surface to catch the biomarker out of the body fluid. So far, the immuno-infrared sensor can be used only once and requires time-consuming steps of sensor exchange, sensor cleaning, and novel surface functionalization. Here, we developed an immuno-infrared sensor providing a reusable surface and showcase its performance by the detection of the AD biomarker proteins Aβ and Tau in human cerebrospinal fluid (CSF). The sensor surface is covalently coated with the immunoglobulin binding proteins Protein A or Protein G. These were employed for noncovalent immobilization of antibodies and the subsequent immobilization and analysis of their antigens. The reversible antibody immobilization can be repeated several times with the same or different antibodies. Further, the more specific binding of the antibody via its Fc region instead of the conventional NHS coupling leads to a 3-4-fold higher antigen binding capacity of the antibody. Thus, the throughput, sensitivity, and automation capacity of the immuno-infrared biosensor are significantly increased as compared to former immuno-infrared assays. This immuno-sensor can be used with any antibody that binds to Protein A or Protein G.
用于医疗目的的生物传感器的发展是一个不断增长的领域。已经开发出用于在体液中临床前检测阿尔茨海默病（AD）的免疫-红外生物传感器。该传感器的关键元件是具有化学修饰表面的 ATR 晶体，用于从体液中捕获生物标志物。到目前为止，免疫-红外传感器只能使用一次，并且需要耗时的传感器更换、传感器清洁和新的表面功能化步骤。在这里，我们开发了一种免疫-红外传感器，提供了可重复使用的表面，并通过检测人脑脊液（CSF）中的 AD 生物标志物蛋白 Aβ和 Tau 展示了其性能。传感器表面通过共价涂层与免疫球蛋白结合蛋白 Protein A 或 Protein G 结合。这些用于非共价固定化抗体，随后固定化并分析其抗原。相同或不同的抗体可以重复进行可重复的抗体固定化。此外，抗体通过其 Fc 区域的更特异性结合而不是传统的 NHS 偶联导致抗体的抗原结合能力提高了 3-4 倍。因此，与以前的免疫-红外测定相比，免疫-红外生物传感器的通量、灵敏度和自动化能力显著提高。这种免疫传感器可以与任何结合蛋白 A 或蛋白 G 的抗体一起使用。
