Microfluidic cell separation by deformability

从血液和海水等不同的混合物中快速、有效地分离特定表型的细胞，在生物和健康科学的许多领域都很重要。通常，所需的细胞类型，如间充质干细胞和循环肿瘤细胞，极其罕见，与主要群体相比，比例从1：10^5到1：10^11不等。传统的细胞分选技术使用一系列物理参数和化学相互作用来区分特定的细胞类型。物理技术不能提供足够的选择性来分离稀有细胞。化学技术是不可取的，因为所需的处理步骤可能会阻止细胞恢复以进行进一步分析或移植到体内。最近在使用微流控结构的无标记细胞分离方面的工作表明，在低流速下基于尺寸的分离，但在较高流速时有被堵塞的趋势。这些目前机制的根本限制是它们处理大量细胞的能力，同时保持足够的选择性来分离特定的稀有细胞类型。我们建议的研究计划将通过开发新的机制来解决这些限制，该机制通过细胞的机械变形能力来分离细胞，先前的AFM研究表明，不同类型的细胞之间存在显著差异。利用在流动中主动变形细胞的方法，所提出的分离机制能够在高流速下处理大量细胞而不会堵塞。通过利用单个细胞大小的结构的微制造，利用仪器技术以纳米精度机械变形结构，以及使用多层软光刻工具对流动进行精确控制，该研究计划旨在创造一种“变形能力光谱仪”。

Fast, efficient isolation of specific phenotypes of cells from heterogeneous mixtures, such as blood and sea water, is important in many areas of biological and health sciences. Frequently, the desired cell types, such as Mesenchymal stem cells and circulating tumor cells, are extremely rare, with fractions ranging from 1:10^5 to 1:10^11 compared to the main population. Traditional cell sorting techniques use a range of physical parameters and chemical interactions to discriminate specific cell types. Physical techniques do not offer sufficient selectivity to isolate rare cells. Chemical techniques are undesirable because the processing steps required may prevent the recovery of cells for further analysis or transplantation into the body. Recent work in label-free cell separations using microfluidics structures has demonstrated size-based separation at low flow rates, but has a tendency to be clogged at higher flow rates. The fundamental limitation of these current mechanisms is their ability to process vast quantities of cells while remaining selective enough to isolate specific rare cell types. Our proposed research program will address these limitations by developing new mechanisms that separate cells by their mechanical deformability, which prior AFM studies have shown to vary significantly across different cell types. Using the approach to actively deform cells in flow, the proposed separation mechanisms are capable of processing vast quantities of cells at high flow rate without clogging. By leveraging microfabrication of structures at the size scale of individual cells, with instrumentation techniques to mechanically deform structures with nanometer precision, as well as, precise control of flow in using the tools of multilayer soft lithography, this research program aims to create a 'deformability spectrometer'.