Departament of Biomedical Engineering, Lund University, Lund, Sweden.
Sci Rep. 2018 Jun 14;8(1):9156. doi: 10.1038/s41598-018-25551-0.
Sepsis is a common and often deadly systemic response to an infection, usually caused by bacteria. The gold standard for finding the causing pathogen in a blood sample is blood culture, which may take hours to days. Shortening the time to diagnosis would significantly reduce mortality. To replace the time-consuming blood culture we are developing a method to directly separate bacteria from red and white blood cells to enable faster bacteria identification. The blood cells are moved from the sample flow into a parallel stream using acoustophoresis. Due to their smaller size, the bacteria are not affected by the acoustic field and therefore remain in the blood plasma flow and can be directed to a separate outlet. When optimizing for sample throughput, 1 ml of undiluted whole blood equivalent can be processed within 12.5 min, while maintaining the bacteria recovery at 90% and the blood cell removal above 99%. That makes this the fastest label-free microfluidic continuous flow method per channel to separate bacteria from blood with high bacteria recovery (>80%). The high throughput was achieved by matching the acoustic impedance of the parallel stream to that of the blood sample, to avoid that acoustic forces relocate the fluid streams.
脓毒症是一种常见且通常致命的全身感染反应，通常由细菌引起。在血液样本中寻找病原体的金标准是血液培养，这可能需要数小时到数天。缩短诊断时间将显著降低死亡率。为了替代耗时的血液培养，我们正在开发一种从红细胞和白细胞中直接分离细菌的方法，以实现更快的细菌鉴定。通过声悬浮作用，将血细胞从样品流转移到平行流中。由于细菌体积较小，不会受到声场的影响，因此仍留在血浆流中，并可被引导至单独的出口。在优化样品通量时，可在 12.5 分钟内处理 1ml 未稀释的全血当量，同时保持 90%的细菌回收率和超过 99%的血细胞去除率。这使得该方法成为每个通道中最快的无需标签的连续流微流控细菌分离方法，具有高细菌回收率（>80%）。通过使平行流的声阻抗与血液样品的声阻抗相匹配，避免声力重新定位流体流，从而实现了高通量。
