Caulum Meghan M, Murphy Brian M, Ramsay Lauren M, Henry Charles S
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
Anal Chem. 2007 Jul 15;79(14):5249-56. doi: 10.1021/ac070452v. Epub 2007 Jun 13.
Biomarkers provide clinicians with an important tool for disease assessment. Many different biomarkers have been discovered, but few of them suffice as stand-alone indicators for disease presence or prognosis. Because no single biomarker can be relied upon for accurate disease detection there has been a substantial push for new multianalyte screening methods. Furthermore, there is a need to push assays toward a point-of-care technology to reduce the time between clinical analysis and medical intervention and minimize artifacts created during sample storage. There currently are, however, few inexpensive multianalyte methods for disease detection that can function in a point-of-care setting. A new approach which bridges the gap between traditional immunoassays and high-density microarrays by utilizing microfluidics, immunoassays, and micellar electrokinetic chromatography (MEKC) is discussed here. This chemistry, the cleavable tag immunoassay (CTI), is a low- to medium-density heterogeneous immunoassay designed to detect 1-20 analytes simultaneously. Although similar to traditional sandwich immunoassays, this approach is unique because the signal is not imaged on the surface; instead, a fluorescent tag is chemically cleaved from the antibody and analyzed by microchip MEKC. In this report, the CTI chemistry is used for the detection of four cardiac biomarkers elevated in acute myocardial infarction. Limit of detection (LOD) and dynamic range are reported for all biomarkers with LODs on the order of low nanograms per milliliter to low picograms per milliliter. Most importantly, the dynamic range for each of the biomarkers spans the boundary between normal and elevated levels. Finally, elevated marker levels were measured in spiked human serum samples.
生物标志物为临床医生提供了一种重要的疾病评估工具。已经发现了许多不同的生物标志物，但其中很少有能作为疾病存在或预后的独立指标。由于没有单一的生物标志物能可靠地用于准确的疾病检测，因此大力推动了新的多分析物筛查方法的发展。此外，还需要将检测方法推向即时检测技术，以减少临床分析和医疗干预之间的时间，并最大限度地减少样本储存过程中产生的假象。然而，目前很少有廉价的用于疾病检测的多分析物方法能够在即时检测环境中发挥作用。本文讨论了一种通过利用微流体技术、免疫测定和胶束电动色谱法（MEKC）弥合传统免疫测定和高密度微阵列之间差距的新方法。这种化学方法，即可裂解标签免疫测定（CTI），是一种低密度至中密度的非均相免疫测定，旨在同时检测1至20种分析物。尽管与传统的夹心免疫测定相似，但这种方法的独特之处在于信号不在表面成像；相反，荧光标签从抗体上化学裂解下来，并通过微芯片MEKC进行分析。在本报告中，CTI化学方法用于检测急性心肌梗死中升高的四种心脏生物标志物。报告了所有生物标志物的检测限（LOD）和动态范围，LOD在每毫升低纳克至每毫升低皮克的范围内。最重要的是，每种生物标志物的动态范围跨越了正常水平和升高水平之间的界限。最后，在加标的人血清样本中测量了升高的标志物水平。
