Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens-Lyngby, Denmark.
Analyst. 2019 Jan 14;144(2):602-610. doi: 10.1039/c8an01197d.
Blood plasma evaluation has high significance in clinical diagnostics. Current schemes involve the preparation of blood plasma by centrifugation of whole blood followed by electrochemical or spectroscopic analysis. However, centrifugation is often too time-consuming for application in clinical emergency and point-of-care settings. We propose to combine microfluidic, instantaneous plasma fractionation with localized spectroscopic methods for in-line analysis. As an example, we present confocal Raman spectroscopy in fractionated plasma domains at two different Raman excitation wavelengths. Resonance Raman spectroscopy with laser excitation at 408 nm allows the specific detection of free hemoglobin in blood plasma at concentrations above 22 mg dl-1 (level of detection). Consequently, we are able to accurately resolve the range of clinical relevance regarding hemolysis. At near-infrared excitation (785 nm) we furthermore demonstrate the acquisition of characteristic Raman spectra of fractionated blood plasma in the microfluidic setting. These spectra can serve as starting point for a multi-parameter regression analysis to quantify a set of blood plasma parameters from a single Raman spectrum. The combined microfluidics and Raman spectroscopy method is non-destructive and has a whole blood consumption of less than 100 μl per hour. It thus allows for continuous in-line blood plasma monitoring.
血浆评估在临床诊断中具有重要意义。目前的方案包括通过全血离心制备血浆，然后进行电化学或光谱分析。然而，离心对于在临床急诊和即时护理环境中的应用来说往往过于耗时。我们建议将微流控、瞬时血浆分离与局部光谱方法相结合，用于在线分析。例如，我们在两个不同的拉曼激发波长下展示了分馏血浆域中的共焦拉曼光谱。以 408nm 的激光激发的共振拉曼光谱允许在血浆中游离血红蛋白浓度高于 22mgdl-1（检测限）的情况下进行特异性检测。因此，我们能够准确地解析与溶血相关的临床相关范围。在近红外激发（785nm）下，我们还展示了在微流控环境中分馏血液血浆的特征拉曼光谱的获取。这些光谱可以作为多元回归分析的起点，从单个拉曼光谱中定量一组血浆参数。该组合的微流控和拉曼光谱方法是非破坏性的，每小时消耗的全血少于 100μl。因此，它允许连续的在线血浆监测。
