Bozdogan Anıl, El-Kased Reham F, Jungbluth Vanessa, Knoll Wolfgang, Dostalek Jakub, Kasry Amal
CEST Competence Centre for Electrochemical Surface Technology, 2700 Wiener Neustadt, Austria.
Biosensor Technologies, AIT-Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria.
R Soc Open Sci. 2020 Oct 7;7(10):200871. doi: 10.1098/rsos.200871. eCollection 2020 Oct.
Using an immunoassay in combination with surface plasmon fluorescence spectroscopy (SPFS), we report the rapid detection of troponin I, a valuable biomarker for diagnosis of myocardial infarction. We discuss the implementation of (i) direct, (ii) sandwich, and (iii) competitive assay formats, based on surface plasmon resonance and SPFS. To elucidate the results, we relate the experiments to orientation-dependent interaction of troponin I epitopes with respective immunoglobulin G antibodies. A limit of detection (LoD) of 19 pM, with 45 min readout time, was achieved using single monoclonal antibody that is specific for one epitope. The borderline between normal people and patients is 20 pM to 83 pM cTnI concentration, and upon the outbreak of acute myocardial infraction it can raise to 2 nM and levels at 20 nM for 6-8 days, therefore the achieved LoD covers most of the clinically relevant range. In addition, this system allows for the detection of troponin I using a single specific monoclonal antibody, which is highly beneficial in case of detection in real samples, where the protein has a complex form leading to hidden epitopes, thus paving the way towards a system that can improve early-stage screening of heart attacks.
我们利用免疫测定法结合表面等离子体荧光光谱法（SPFS），实现了对肌钙蛋白I的快速检测，肌钙蛋白I是诊断心肌梗死的一种重要生物标志物。我们讨论了基于表面等离子体共振和SPFS的（i）直接法、（ii）夹心法和（iii）竞争法检测形式的实施情况。为了阐明结果，我们将实验与肌钙蛋白I表位与相应免疫球蛋白G抗体的取向依赖性相互作用联系起来。使用针对一个表位的单克隆抗体，实现了19 pM的检测限，读出时间为45分钟。正常人和患者之间的临界值为20 pM至83 pM的肌钙蛋白I浓度，急性心肌梗死发作时可升至2 nM，并在20 nM水平维持6 - 8天，因此所实现的检测限涵盖了大部分临床相关范围。此外，该系统允许使用单一特异性单克隆抗体检测肌钙蛋白I，这在实际样品检测中非常有利，因为实际样品中的蛋白质具有复杂形式，会导致表位隐藏，从而为能够改进心脏病早期筛查的系统铺平了道路。
