BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Shriners Hospital for Children and Harvard Medical School, Boston, Massachusetts 02114, USA.
Anal Chem. 2010 May 1;82(9):3862-7. doi: 10.1021/ac100387b.
Microfluidic inertial focusing has been demonstrated to be an effective method for passively positioning microparticles and cells without the assistance of sheath fluid. Because inertial focusing produces well-defined lateral equilibrium particle positions in addition to highly regulated interparticle spacing, its value in flow cytometry has been suggested. Particle focusing occurs in straight channels and can be manipulated through cross sectional channel geometry by the introduction of curvature. Here, we present a staged channel design consisting of both curved and straight sections that combine to order particles into a single streamline with longitudinal spacing. We have evaluated the performance of these staged inertial focusing channels using standard flow cytometry methods that make use of calibration microspheres. Our analysis has determined the measurement precision and resolution, as a function of flow velocity and particle concentration that is provided by these channels. These devices were found to operate with increasing effectiveness at higher flow rates and particle concentrations, within the examined ranges, which is ideal for high throughput analysis. Further, the prototype flow cytometer equipped with an inertial focusing microchannel matched the resolution provided by a commercial hydrodynamic focusing flow cytometer. Most notably, our analysis indicates that the inertial focusing channels virtually eliminated particle coincidence at the analysis point. These properties suggest a potentially significant role for inertial focusing in the development of inexpensive flow cytometry-based diagnostics and in applications requiring the analysis of high particle concentrations.
微流控惯性聚焦已被证明是一种无需鞘液辅助即可被动定位微颗粒和细胞的有效方法。由于惯性聚焦除了产生高度调节的颗粒间间隔外，还产生了明确定义的侧向平衡颗粒位置，因此它在流式细胞术中的价值已得到了体现。颗粒聚焦发生在直通道中，并且可以通过横截面通道几何形状的引入通过曲率进行操纵。在这里，我们提出了一种由弯曲和直部分组成的分级通道设计，该设计将组合起来将颗粒有序地排列成具有纵向间隔的单个流线。我们使用标准的流式细胞术方法评估了这些分级惯性聚焦通道的性能，这些方法利用校准微球。我们的分析确定了这些通道提供的流速和颗粒浓度的测量精度和分辨率。这些设备在检查范围内的较高流速和颗粒浓度下的效果越来越好，这非常适合高通量分析。此外，配备惯性聚焦微通道的原型流式细胞仪与商用流体动力聚焦流式细胞仪提供的分辨率相匹配。值得注意的是，我们的分析表明，惯性聚焦通道几乎消除了分析点处的颗粒重合。这些特性表明惯性聚焦在开发廉价的基于流式细胞术的诊断方法以及在需要分析高颗粒浓度的应用中可能具有重要作用。
