State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, PR China.
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Biosens Bioelectron. 2018 May 30;106:99-104. doi: 10.1016/j.bios.2018.01.061. Epub 2018 Feb 1.
Sensitive detection of cardiac biomarkers is critical for clinical diagnostics of myocardial infarction (MI) while such detection is quite challenging due to the ultra-low concentration of cardiac biomarkers. In this work, a label-free immunosensor based on optical microfiber coupler (OMC) has been developed for the ultrasensitive detection of cardiac troponin I (cTnI), a selective and highly sensitive biomarker of acute myocardial infarction (AMI). CTnI monoclonal antibodies were immobilized on the surface of the fiber through polyelectrolyte layer using layer-by-layer deposition technique. For refractive index sensing characterization, an ultra-high sensitivity of 91777.9 nm/RIU was achieved when the OMC works around the dispersion turning point, which is the highest experimental demonstration in the field of fiber-optic evanescent biosensors. For biosensing, the immunosensor with good specificity showed a linear wavelength shift in the range of 2-10 fg/mL and an ultra-low detection limit of 2 fg/mL. Such immunosensors have huge application potential for the detection of cardiac biomarkers of myocardial infarction due to simple detection scheme, quick response time, ease of handling and miniaturation.
超敏检测心肌标志物对于心肌梗死（MI）的临床诊断至关重要，但由于心肌标志物的浓度极低，因此此类检测极具挑战性。在这项工作中，我们开发了一种基于光纤耦合器（OMC）的无标记免疫传感器，用于超敏检测心肌肌钙蛋白 I（cTnI），这是急性心肌梗死（AMI）的一种选择性和高灵敏度的生物标志物。通过层层沉积技术，将 CTnI 单克隆抗体固定在纤维表面的聚电解质层上。为了进行折射率传感特性分析，当 OMC 工作在色散转折点附近时，实现了 91777.9nm/RIU 的超高灵敏度，这是光纤倏逝生物传感器领域的最高实验演示。在生物传感方面，该免疫传感器具有良好的特异性，在 2-10 fg/mL 范围内表现出线性波长移动，检测限低至 2 fg/mL。由于检测方案简单、响应时间快、易于操作和小型化，这种免疫传感器在检测心肌梗死的心肌标志物方面具有巨大的应用潜力。
