Butement Jonathan T, Holloway Paul M, Welsh Joshua A, Holloway Judith A, Englyst Nicola A, Horak Peter, West Jonathan, Wilkinson James S
Optoelectronics Research Centre, University of Southampton, UK.
Lab Chip. 2020 Apr 7;20(7):1267-1280. doi: 10.1039/c9lc01182j. Epub 2020 Mar 9.
Size measurement of extracellular vesicles is hampered by the high cost and measurement uncertainty of conventional flow cytometers which is mainly due to the use of non-specialised free space optics. Integrated cytometry, where the optics and fluidics are embedded in a monolithic chip shows promise for the production of low cost, micro-flow cytometers dedicated for extracellular vesicle (EV) analysis with improved size measurement accuracy and precision. This research demonstrates a unique integrated cytometer for sub-micron particle size measurement using multi-angle scattering analysis. A combination of three technologies is used: (i) Dean-based hydrodynamic focussing to deliver a tight sample core stream to the analysis region, (ii) integrated waveguides with multimode interference devices to focus a narrow excitation beam onto the sample stream, and (iii) an angular array of collection waveguides to measure particle scattering distribution and calculate diameter. Low index 200 nm liposomes could be detected and polystyrene size standards as small as 400 nm diameter could be measured with an uncertainty of ±21 nm (1/2 IQR) demonstrating a first step on the path to high performance integrated cytometry of EVs.
传统流式细胞仪的高成本和测量不确定性阻碍了细胞外囊泡的大小测量，这主要是由于使用了非专用的自由空间光学元件。集成流式细胞术将光学和流体系统集成在一个单片芯片中，有望制造出低成本的微流式细胞仪，专门用于细胞外囊泡（EV）分析，提高大小测量的准确性和精度。本研究展示了一种独特的集成细胞仪，用于通过多角度散射分析测量亚微米颗粒大小。使用了三种技术的组合：（i）基于迪恩流的流体动力学聚焦，将紧密的样品核心流输送到分析区域；（ii）带有多模干涉装置的集成波导，将窄激发光束聚焦到样品流上；（iii）收集波导的角度阵列，用于测量颗粒散射分布并计算直径。可以检测到低折射率200nm的脂质体，直径小至400nm的聚苯乙烯尺寸标准物的测量不确定度为±21nm（1/2四分位间距），这表明在实现高性能EV集成流式细胞术的道路上迈出了第一步。
