Cell-free DNA (cfDNA) has been implicated as an important biomarker in cancer management. Thus, efficient techniques for cfDNA extraction are necessary for precision medicine. We developed a centrifugation-free cfDNA extraction microfluidic chip capable of extracting cfDNA from plasma samples through microfluidic circuits within 15 min under vacuum pressure using an immiscible solvent. The microfluidic chip had excellent performance that was comparable to the most widely used commercial product (QIAamp kit) in terms of extraction efficiency, purity, and quality of DNA samples. The microfluidic chip was validated for the continuous monitoring of HER-2 type breast cancer and was able to successfully detect a point mutation in phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA) during severe liver metastasis. The chip effectively eliminates the repetitive centrifugation processes and dramatically shortened the sample preparation time. The proposed platform could facilitate the development of a sample-to-answer system for use in liquid biopsy of cancers.

无细胞DNA（cfDNA）被认为是癌症治疗中的重要生物标志物。因此，精密医学需要用于cfDNA提取的有效技术。我们开发了一种无离心的cfDNA提取微流体芯片，该芯片能够在15分钟内使用不混溶的溶剂在15分钟内通过微流体回路从血浆样品中提取cfDNA。在提取效率，纯度和DNA样品质量方面，微流体芯片具有与最广泛使用的商业产品（QIAamp试剂盒）相当的出色性能。该微流控芯片经过验证可用于连续监测HER-2型乳腺癌，并能够成功检测到磷脂酰肌醇4,5-双磷酸3激酶（PIK3CA）中的点突变）严重肝转移期间。该芯片有效消除了重复的离心过程，并大大缩短了样品制备时间。拟议的平台可以促进用于癌症液体活检的“样本到答案”系统的开发。