Improved sample preparation has the potential to address unmet needs for fast turnaround sepsis tests. In this work, we report elasto-inertial based rapid bacteria separation from diluted blood at high separation efficiency. In viscoelastic flows, we demonstrate novel findings where blood cells prepositioned at the outer wall entering a spiral device remain fully focused throughout the channel length while smaller bacteria migrate to the opposite wall. Initially, using microparticles, we show that particles above a certain size cut-off remain fully focused at the outer wall while smaller particles differentially migrate toward the inner wall. We demonstrate particle separation at 1 μm resolution at a total throughput of 1 mL/min. For blood-based experiments, a minimum of 1:2 dilution was necessary to fully focus blood cells at the outer wall. Finally, Escherichia coli spiked in diluted blood were continuously separated at a total flow rate of 1 mL/min, with efficiencies between 82 and 90% depending on the blood dilution. Using a single spiral, it takes 40 min to process 1 mL of blood at a separation efficiency of 82%. The label-free, passive, and rapid bacteria isolation method has a great potential for speeding up downstream phenotypic and genotypic analysis.

中文翻译：

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使用弹性惯性微流体从血液中高分辨率和快速分离细菌

改进的样品制备有可能解决快速周转败血症检测的未满足需求。在这项工作中，我们报告了以高分离效率从稀释血液中快速分离细菌的弹性惯性。在粘弹性流动中，我们展示了新的发现，其中预先定位在外壁的血细胞进入螺旋装置在整个通道长度内保持完全聚焦，而较小的细菌迁移到对面的壁。最初，使用微粒，我们表明超过一定尺寸截断的颗粒仍然完全集中在外壁，而较小的颗粒则不同地向内壁迁移。我们展示了 1 μm 分辨率下的颗粒分离，总通量为 1 mL/min。对于基于血液的实验，至少需要 1:2 稀释才能将血细胞完全集中在外壁。稀释血液中掺入的大肠杆菌以 1 mL/min 的总流速连续分离，效率在 82% 到 90% 之间，具体取决于血液稀释度。使用单螺旋，以 82% 的分离效率处理 1 mL 血液需要 40 分钟。无标记、被动和快速的细菌分离方法在加速下游表型和基因型分析方面具有巨大潜力。