Extracellular vesicles (EVs) derived from tumor cells have the potential to provide a much-needed source of non-invasive molecular biomarkers for liquid biopsies. However, current methods for EV isolation have limited specificity towards tumor-derived EVs that limit their clinical use. Here, we present an approach called immunomagnetic sequential ultrafiltration (iSUF) that consists of sequential stages of purification and enrichment of EVs (nonspecifically and specifically) in 2h. In iSUF, EVs present in different volumes of biofluids (0.1 mL to 100 mL) can be significantly enriched (up to 1000 times), with 99.9 % removal of contaminating proteins (e.g., albumin). The yields of cell culture media (CCM), serum, and urine EVs corresponded to 98% +/- 3.6%, 94% +/- 2.0% and 95% +/- 2.0%, respectively (p > 0.05). The final step of iSUF enables the separation of tumor-specific EVs by incorporating immunomagnetic beads specific to a target subpopulation of EVs. Serum from a small cohort of clinical samples from metastatic breast cancer patients and healthy donors were processed by the iSUF platform and the isolated EVs from patients showed significantly higher expression levels of breast cancer biomarkers (i.e., HER2, CD24 and miR21).

中文翻译：

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免疫磁序贯超滤（iSUF）平台，用于富集和纯化生物流体中的细胞外囊泡

源自肿瘤细胞的细胞外囊泡（EV）具有为液体活检提供急需的非侵入性分子生物标记物来源的潜力。但是，当前的电动汽车隔离方法对源自肿瘤的电动汽车的特异性有限，从而限制了其临床应用。在这里，我们提出了一种称为免疫磁超滤（iSUF）的方法，该方法由2小时内EV的纯化和富集（非特异性和特异性）的连续阶段组成。在iSUF中，存在于不同体积生物流体（0.1 mL至100 mL）中的EV可以显着富集（最多1000倍），并去除99.9％的污染蛋白（例如白蛋白）。细胞培养基（CCM），血清和尿液电动车的产率分别相当于98％+/- 3.6％，94％+/- 2.0％和95％+/- 2.0％（p> 0.05）。iSUF的最后一步是通过结合对EV的目标亚群特异的免疫磁珠，实现肿瘤特异性EV的分离。iSUF平台处理了来自转移性乳腺癌患者和健康供体的一小批临床样品的血清，并且从患者中分离出的EV显示出乳腺癌生物标志物（即HER2，CD24和miR21）的表达水平明显较高。