目前用于检测循环肿瘤细胞（CTC）的基于标记的技术以细胞的天然表面蛋白为目标，因此仅适用于有限的癌细胞类型。我们报告了通过利用细胞代谢的差异，对外周血单核细胞（PBMC）池中的癌细胞进行光微流体检测。我们采用代谢糖工程作为点击化学工具来标记细胞，与 PBMC 相比，癌细胞产生的荧光信号高出数倍。研究了标记化合物的浓度和细胞孵育时间对荧光信号强度的影响。标记的细胞被封装在液滴中，确保细胞以单列二维聚焦方式进入检测区域，并以高检测效率和低信号变异系数进行光学检测。与成熟且广泛采用的基于抗 EpCAM-FITC 的标记相比，代谢标记方法显示出显着更高的标记效率和平均荧光信号。我们展示了对三种不同癌细胞系的检测——EpCAM 阴性宫颈癌细胞 HeLa、EpCAM 弱阳性和三阴性乳腺癌细胞 MDA-MB-231 以及 EpCAM 强阳性乳腺癌细胞 MCF7，强调了这一点所提出的技术独立于天然存在的细胞表面蛋白并且广泛适用。代谢标记和光学检测的细胞被成功地重新培养，证明了所提出的技术与下游测定的兼容性。然后，所提出的技术用于检测转移性癌症患者血液中的 CTC。目前的工作提供了一种检测血液中癌细胞的新策略，可以在涉及 CTC 的基础研究和临床研究以及单细胞测序中找到潜在的应用。

The currently existing label-based techniques for the detection of circulating tumor cells (CTCs) target natural surface proteins of cells and are therefore applicable to only limited cancer cell types. We report optomicrofluidic detection of cancer cells in the pool of peripheral blood mononuclear cells (PBMCs) by exploiting the difference in their cell metabolism. We employ metabolic glycoengineering as a click chemistry tool for tagging cells that yields several fold-higher fluorescence signals from cancer cells compared to that from PBMCs. The effects of concentrations of the tagging compounds and cell incubation time on the fluorescence signal intensity are studied. The tagged cells were encapsulated in droplets ensuring that cells enter the detection region two-dimensionally focused in single-file and optically detected with a high detection efficiency and low coefficient of variation of the signals. The metabolic tagging approach showed a significantly higher tagging efficiency and average fluorescence signal compared to the well-established and widely adopted anti-EpCAM-FITC-based tagging. We demonstrated the detection of three different cancer cell lines - EpCAM-negative cervical cancer cell, HeLa, weakly EpCAM positive, and triple-negative breast cancer cell, MDA-MB-231, and strongly EpCAM positive breast cancer cell, MCF7, highlighting that the proposed technique is independent of naturally occurring cell surface proteins and widely applicable. The metabolically tagged and optically detected cells were successfully recultured, proving the compatibility of the proposed technique with downstream assays. The proposed technique is then utilised for the detection of CTCs in metastatic cancer patients' blood. The current work provides a new strategy for detecting cancer cells in the blood that can find potential applications in both fundamental research and clinical studies involving CTCs as well as in single-cell sequencing.