Bhuvanendran Nair Gourikutty Sajay, Chang Chia-Pin, Poenar Daniel Puiu
BioElectronics Programme, Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-02, Innovis, 117528, Singapore; NOVITAS-Centre for Micro-/Nano-electronics, School of Electrical and Electronics Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
BioElectronics Programme, Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-02, Innovis, 117528, Singapore.
J Chromatogr B Analyt Technol Biomed Life Sci. 2016 Aug 15;1028:153-164. doi: 10.1016/j.jchromb.2016.06.016. Epub 2016 Jun 14.
The study of cancer cells in blood, popularly called circulating tumour cells (CTCs), has exceptional prospects for cancer risk assessment and analysis. Separation and enrichment of CTCs by size-based methods suffer from a well-known recovery/purity trade-off while methods targeting certain specific surface proteins can lead to risk of losing CTCs due to Epithelial to Mesenchymal Transition (EMT) and thus adversely affect the separation efficiency. A negative selection approach is thus preferred for tumour cell isolation as it does not depend on biomarker expression or defines their physical property as the separation criteria. In this work, we developed a microfluidic chip to isolate CTCs from whole blood samples without targeting any tumour specific antigen. This chip employs a two-stage cell separation: firstly, magnetophoresis depletes the white blood cells (WBCs) from a whole blood sample and is then followed by a micro-slit membrane that enables depleting the red blood cells (RBCs) and retaining only the tumour cells. By creating strong magnetic field gradients along with customized antibody complexes to target WBCs, we are able to remove >99.9% of WBCs from 1:1 diluted blood at a sample processing rate of 500μL/min. This approach achieves an average of >80% recovery of spiked tumour cells from 2mL of whole blood in a total assay processing time of 50min without multiple processing steps.
对血液中癌细胞的研究，通俗地称为循环肿瘤细胞（CTCs），在癌症风险评估和分析方面有着非凡的前景。基于大小的方法对CTCs进行分离和富集存在着众所周知的回收率/纯度权衡问题，而针对某些特定表面蛋白的方法可能会因上皮-间质转化（EMT）导致CTCs丢失，从而对分离效率产生不利影响。因此，负选法更适合用于肿瘤细胞分离，因为它不依赖生物标志物表达，也不以其物理特性作为分离标准。在这项工作中，我们开发了一种微流控芯片，可从全血样本中分离CTCs，而无需靶向任何肿瘤特异性抗原。该芯片采用两阶段细胞分离：首先，磁泳从全血样本中去除白细胞（WBCs），然后通过微缝膜去除红细胞（RBCs），只保留肿瘤细胞。通过创建强磁场梯度以及定制抗体复合物来靶向WBCs，我们能够以500μL/min的样本处理速率从1:1稀释的血液中去除>99.9%的WBCs。这种方法在50分钟的总检测处理时间内，无需多个处理步骤，就能从2mL全血中平均回收>80%的加标肿瘤细胞。
