Infrared Microspectroscopy of Live Cells in Microfluidic Devices (MD-IRMS): Toward a Powerful Label-Free Cell-Based Assay
Infrared Microspectroscopy of Live Cells in Microfluidic Devices (MD-IRMS): Toward a Powerful Label-Free Cell-Based Assay
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DOI：
10.1021/ac300313x
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发表时间：
2012-06-05
影响因子：
7.4
通讯作者：
Grenci, G.
中科院分区：
文献类型：
--
作者：
Vaccari, L.;Birarda, G.;Grenci, G.
到目前为止，大多数生物样品(即组织或细胞)的红外显微光谱(IRMS)实验都是常规地在固定或干燥的样品上进行，以避免吸水问题。在这篇论文中，我们展示了由于新的生物兼容的红外可见透明微流控器件(MD)的发展，将体外IRMS实验的范围扩大到活细胞样品的振动分析的可能性。为了突出IRMS在MD(MD-IRMS)中的生物学相关性，我们系统地研究了不同固定方案、70%乙醇和4%甲醛溶液以及风干对U937白血病单核细胞的生化变化，比较了U937白血病单核细胞与活体U937的IR振动特征。固定和风干过程都不同程度地影响了脂质的组成和顺序以及蛋白质的结构，同时它们都引起了核酸的结构变化。因此，只有活细胞的IRMS才能提供关于DNA和RNA结构及其细胞动力学的可靠信息。综上所述，我们证明了活细胞的MD-IRMS是可行的、可靠的，并且具有生物学相关性，可以被认为是一种基于细胞的无标记检测方法。
Until nowadays most infrared microspectroscopy (IRMS) experiments on biological specimens (i.e., tissues or cells) have been routinely carried out on fixed or dried samples in order to circumvent water absorption problems. In this paper, we demonstrate the possibility to widen the range of in-vitro IRMS experiments to vibrational analysis of live cellular samples, thanks to the development of novel biocompatible IR-visible transparent microfluidic devices (MD). In order to highlight the biological relevance of IRMS in MD (MD-IRMS), we performed a systematic exploration of the biochemical alterations induced by different fixation protocols, ethanol 70% and formaldehyde solution 4%, as well as air-drying on U937 leukemic monocytes by comparing their IR vibrational features with the live U937 counterpart. Both fixation and air-drying procedures affected lipid composition and order as well as protein structure at a different extent while they both induced structural alterations in nucleic acids. Therefore, only IRMS of live cells can provide reliable information on both DNA and RNA structure and on their cellular dynamic. In summary, we show that MD-IRMS of live cells is feasible, reliable, and biologically relevant to be recognized as a label-free cell-based assay.