Cell free DNA (cfDNA) is degraded DNA fragments found in the blood plasma of cancer patients. While cfDNA is a good marker for early diagnostics and cancer prognosis, the extraction of cfDNA from whole blood and sample preparation for later sequencing is still challenging. Here, we presented a microfluidic device for the removal of cells from a cfDNA sample in a first step. In a second step, carboxylated magnetic beads were used for cfDNA extraction and purification. Lastly, cfDNA was amplified using a low-power, plasmonic polymerase chain reaction (PCR) system. Using fluorescent-labeled beads, we demonstrated that the separation efficiency for cells was 99% and the mixing efficiency for purification of cfDNA was 94%. Captured cfDNA could be successfully amplified by PCR, as demonstrated by gel electrophoresis. We confirmed that the limit of detection of our microfluidic system was 10 ng/mL.

中文翻译：

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微流控设备中cfDNA的分离，纯化和检测

无细胞DNA（cfDNA）是在癌症患者血浆中发现的降解DNA片段。尽管cfDNA是早期诊断和癌症预后的良好标志物，但从全血中提取cfDNA和样品制备以用于后续测序仍具有挑战性。在这里，我们介绍了一种用于第一步从cfDNA样品中去除细胞的微流控设备。在第二步中，将羧化的磁珠用于cfDNA提取和纯化。最后，使用低功率等离子体聚合酶链反应（PCR）系统扩增cfDNA。使用荧光标记的珠子，我们证明细胞的分离效率为99％，纯化cfDNA的混合效率为94％。如凝胶电泳所示，捕获的cfDNA可通过PCR成功扩增。