González Itziar, Andrés Roque Rubén, Pinto Alberto, Carreras Pilar
Group of Ultrasonic Resonators RESULT, ITEFI, National Research Council of Spain CSIC 1, 28006 Madrid, Spain.
Micromachines (Basel). 2020 Jul 31;11(8):751. doi: 10.3390/mi11080751.
Acoustophoretic blood plasma separation is based on cell enrichment processes driven by acoustic radiation forces. The combined influence of hematocrit and hydrodynamics has not yet been quantified in the literature for these processes acoustically induced on blood. In this paper, we present an experimental study of blood samples exposed to ultrasonic standing waves at different hematocrit percentages and hydrodynamic conditions, in order to enlighten their individual influence on the acoustic response of the samples. The experiments were performed in a glass capillary (700 µm-square cross section) actuated by a piezoelectric ceramic at a frequency of 1.153 MHz, hosting 2D orthogonal half-wavelength resonances transverse to the channel length, with a single-pressure-node along its central axis. Different hematocrit percentages = 2.25%, 4.50%, 9.00%, and 22.50%, were tested at eight flow rate conditions of Q = 0:80 µL/min. Cells were collected along the central axis driven by the acoustic radiation force, releasing plasma progressively free of cells. The study shows an optimal performance in a flow rate interval between 20 and 80 µL/min for low hematocrit percentages ≤ 9.0%, which required very short times close to 10 s to achieve cell-free plasma in percentages over 90%. This study opens new lines for low-cost personalized blood diagnosis.
声泳血浆分离基于由声辐射力驱动的细胞富集过程。对于这些在血液上声学诱导的过程，血细胞比容和流体动力学的综合影响在文献中尚未得到量化。在本文中，我们对处于不同血细胞比容百分比和流体动力学条件下暴露于超声驻波的血样进行了实验研究，以阐明它们对样品声学响应的各自影响。实验在一个由压电陶瓷驱动、频率为1.153 MHz的玻璃毛细管（横截面为700 µm见方）中进行，该毛细管具有与通道长度垂直的二维正交半波长共振，沿其中心轴有一个单压力节点。在Q = 0:80 µL/min的八个流速条件下测试了不同的血细胞比容百分比 = 2.25%、4.50%、9.00%和22.50%。细胞在声辐射力的驱动下沿中心轴收集，逐渐释放出不含细胞的血浆。研究表明，对于血细胞比容百分比≤9.0%的低血细胞比容情况，在20至80 µL/min的流速区间内具有最佳性能，这需要非常短的时间（接近10秒）就能实现无细胞血浆百分比超过90%。这项研究为低成本个性化血液诊断开辟了新途径。
