Based on droplet microfluidics, we demonstrate a new method that can quantitatively measure the somatic cell count (SCC) of fat-free milk. A T-junction microdroplet generator is designed and monodisperse milk droplets can be produced in the T-junction microchannel by pressure-driven microfluidic flows. A mathematical model of the droplet length L_d/w_c as a function of the somatic cell count (SCC) is established. In particular, while monodisperse droplets are generated at low capillary numbers (Ca ≤ 0.1), a linear relation between L_d/w_c and 1/SCC is shown for different geometrical parameters of the T-junctions. Meanwhile, when the somatic cell count of the milk varies from 20 × 10⁴ mL⁻¹ to 300 × 10⁴ mL⁻¹, a linear relation is validated experimentally for a specific geometry of the T-junction. More importantly, by testing the length of the milk droplets, which are produced in the T-junction microdroplet generator, the somatic cell count of the milk can be quantified accurately. Additionally, the measuring precision of the milk's somatic cell count is studied experimentally for various geometries of the T-junctions.

中文翻译：

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基于液滴微流控技术的无脂牛奶体细胞计数定量测量

基于液滴微流控技术，我们演示了一种可以定量测量无脂牛奶的体细胞计数（SCC）的新方法。设计了一个T型结微滴发生器，可以通过压力驱动的微流体流在T型结微通道中产生单分散的乳滴。建立了液滴长度L _d / w _c作为体细胞计数（SCC）的函数的数学模型。特别地，虽然在低毛细管数（Ca≤0.1）下产生单分散液滴，但对于T型结的不同几何参数，L _d / w _c和1 / SCC之间存在线性关系。同时，当牛奶的体细胞数从20×10变化时⁴ mL ^-1至300×10 ⁴ mL ^-1，对于特定的T型结几何形状，实验验证了线性关系。更重要的是，通过测试在T型接头微滴发生器中产生的牛奶滴的长度，可以准确地定量牛奶的体细胞计数。此外，还针对各种几何形状的T型接头实验研究了牛奶体细胞计数的测量精度。