Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan 430072, PR China.
Lab Chip. 2016 Apr 7;16(7):1214-23. doi: 10.1039/c5lc01555c.
The detection of circulating tumor cells (CTCs), a kind of "liquid biopsy", represents a potential alternative to noninvasive detection, characterization and monitoring of carcinoma. Many previous studies have shown that the number of CTCs has a significant relationship with the stage of cancer. However, CTC enrichment and detection remain notoriously difficult because they are extremely rare in the bloodstream. Herein, aided by a microfluidic device, an immunomagnetic separation system was applied to efficiently capture and in situ identify circulating tumor cells. Magnetic nanospheres (MNs) were modified with an anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody to fabricate immunomagnetic nanospheres (IMNs). IMNs were then loaded into the magnetic field controllable microfluidic chip to form uniform IMN patterns. The IMN patterns maintained good stability during the whole processes including enrichment, washing and identification. Apart from its simple manufacture process, the obtained microfluidic device was capable of capturing CTCs from the bloodstream with an efficiency higher than 94%. The captured cells could be directly visualized with an inverted fluorescence microscope in situ by immunocytochemistry (ICC) identification, which decreased cell loss effectively. Besides that, the CTCs could be recovered completely just by PBS washing after removal of the permanent magnets. It was observed that all the processes showed negligible influence on cell viability (viability up to 93%) and that the captured cells could be re-cultured for more than 5 passages after release without disassociating IMNs. In addition, the device was applied to clinical samples and almost all the samples from patients showed positive results, which suggests it could serve as a valuable tool for CTC enrichment and detection in the clinic.
循环肿瘤细胞（CTC）的检测是一种“液体活检”，代表了一种潜在的替代方法，可用于非侵入性检测、表征和监测癌症。许多先前的研究表明，CTC 的数量与癌症的阶段有显著的关系。然而，CTC 的富集和检测仍然非常困难，因为它们在血液中极其罕见。在此，借助微流控装置，应用免疫磁分离系统来有效地捕获和原位识别循环肿瘤细胞。磁性纳米球（MNs）被修饰有抗上皮细胞黏附分子（anti-EpCAM）抗体，以制备免疫磁纳米球（IMNs）。然后，将 IMNs 加载到磁场可控的微流控芯片中，形成均匀的 IMN 图案。在包括富集、洗涤和鉴定在内的整个过程中，IMN 图案保持良好的稳定性。除了简单的制造工艺外，所获得的微流控装置能够从血液中捕获 CTC 的效率高于 94%。捕获的细胞可以通过免疫细胞化学（ICC）鉴定在体直接用倒置荧光显微镜观察，有效地减少细胞损失。此外，在去除永久磁铁后，只需用 PBS 洗涤即可完全回收 CTC。观察到所有过程对细胞活力（活力高达 93%）的影响都可以忽略不计，并且捕获的细胞在释放后可以重新培养超过 5 代，而不会分离 IMNs。此外，该装置还应用于临床样本，几乎所有患者样本都显示出阳性结果，这表明它可以作为 CTC 富集和临床检测的有价值工具。
