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.

使用免疫分析结合表面等离子体荧光光谱法（SPFS），我们报告了肌钙蛋白I的快速检测，肌钙蛋白I是诊断心肌梗死的重要生物标志物。我们讨论了基于表面等离振子共振和SPFS的（i）直接，（ii）三明治和（iii）竞争测定形式的实现。为了阐明结果，我们将实验与肌钙蛋白I表位与各自的免疫球蛋白G抗体的方向依赖性相互作用相关。使用对一个表位具有特异性的单一单克隆抗体，检测限（LoD）为19 pM，读取时间为45分钟。正常人和患者之间的临界点是20 pM至83 pM cTnI浓度，急性心肌梗死爆发时，它可以升高2 nM，并在6-8天达到20 nM的水平，因此，获得的LoD涵盖了大多数临床相关范围。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，这对于在真实样品中进行检测非常有益，在真实样品中，蛋白具有导致隐藏表位的复杂形式，从而为系统铺平了道路。可以改善心脏病发作的早期筛查。