Cheung Lucia S, Sahloul Sarah, Orozaliev Ajymurat, Song Yong-Ak
Division of Engineering, New York University Abu Dhabi, PO Box 129188, Abu Dhabi, UAE.
Department of Chemical and Biomolecular Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA.
Micromachines (Basel). 2018 Jun 19;9(6):306. doi: 10.3390/mi9060306.
Exosomes have gained immense importance since their proteomic and genetic contents could potentially be used for disease diagnostics, monitoring of cancer progression, metastasis, and drug efficacy. However, establishing the clinical utility of exosomes has been restricted due to small sizes and high sample loss from extensive sample preparation. Sample loss is particularly critical for body fluids limited in volume and difficult to access, e.g., cerebrospinal fluid. We present a microfluidic technique that locally enhances the concentration of extracellular vesicles extracted from MDA-MB-231 human breast cancer cell lines by using an ion concentration polarization (ICP)-based electrokinetic concentrator. Our design incorporates a trapping mechanism near the conductive polymer membrane; therefore, we can preconcentrate and capture extracellular vesicles simultaneously. Compared with standard fluorescence detection, our method increased the limit of detection (LOD) of extracellular vesicles by two orders of magnitude in 30 min. Our concentrator increased the extracellular vesicle concentration for 5.0 × 10⁷ particles/1 mL (LOD), 5.0 × 10⁸ particles/1 mL, and 5.0 × 10⁸ particles/1 mL by ~100-fold each within 30 min using 45 V. This study demonstrates an alternative platform to simultaneously preconcentrate and capture extracellular vesicles that can be incorporated as part of a liquid biopsy-on-a-chip system for the detection of exosomal biomarkers and analysis of their contents for early cancer diagnosis.
由于外泌体的蛋白质组和基因成分有可能用于疾病诊断、癌症进展监测、转移监测以及药物疗效监测，外泌体已变得极为重要。然而，由于外泌体尺寸小，且大量样品制备会导致高样品损失，外泌体临床应用的建立受到了限制。样品损失对于体积有限且难以获取的体液（例如脑脊液）尤为关键。我们提出了一种微流控技术，该技术通过使用基于离子浓度极化（ICP）的电动浓缩器，局部增强从MDA-MB-231人乳腺癌细胞系中提取的细胞外囊泡的浓度。我们的设计在导电聚合物膜附近纳入了捕获机制；因此，我们可以同时对细胞外囊泡进行预浓缩和捕获。与标准荧光检测相比，我们的方法在30分钟内将细胞外囊泡的检测限（LOD）提高了两个数量级。使用45 V电压，我们的浓缩器在30分钟内将细胞外囊泡浓度分别提高到5.0×10⁷颗粒/1 mL（LOD）、5.0×10⁸颗粒/1 mL和5.0×10⁸颗粒/1 mL，提高了约100倍。本研究展示了一个可同时预浓缩和捕获细胞外囊泡的替代平台，该平台可作为芯片上液体活检系统的一部分，用于检测外泌体生物标志物并分析其内容物以进行早期癌症诊断。
