循环肿瘤细胞（CTC）在癌症临床诊断和治疗上具有极其重要的意义。由于缺乏合适的分离手段，CTC检测在临床上仍无法得到广泛的使用。本项目针对CTC的提取难题，通过探索惯性微流控内惯性力对细胞的聚焦（inertial focusing）机理，研制基于惯性微流控芯片的CTC高效分离技术。项目先采用荧光微球结合高速荧光显微镜及共聚焦显微镜，深入研究不同流体和通道条件下细胞的聚焦位点及动力学过程，并结合微流道设计探索惯性系统中流速、浓度、出口匹配等因素对大小选择性分离（size-selective）分辨率的影响；在此基础上，根据聚焦位点和分辨率的研究结果，设计和优化惯性微流控芯片；最后，依据细胞的特殊性进行系统再优化，利用掺杂癌细胞（如MCF-7）的血液样本进行CTC的分离和富集实验，并通过生化分析量化分离过程对细胞生物特性的影响。通过上述研究为CTC的高灵敏度和高纯度提取难题的解决提供新颖的方案。

Circulating tumor cell (CTC) is a liquid biopsy opening a promising window into cancer biology. Its clinical significance includes cancer early detection, prognostic assessment, monitoring response to treatment and personalized therapy. However, the wide adoption of CTC detection in clinical setting is hindered by the great challenge of CTC isolation. The extreme rarity of CTC in peripheral blood requires any detection technique to offer series of features including high sensitivity/selectivity, high throughput processing, high purity of product, high recovery rate, preservation of biological properties et al.. While existing techniques meet some of these features, i.e., immunoselection-based approaches allowing high specificity, there are critical tradeoffs (throughput, purity, efficiency et al.). This work proposes a novel size-selective approach for CTC isolation using inertial microfluidics, which aims to provide a better solution to the grand challenge of CTC isolation. This approach takes the advantages of inertial forces interacting with cells flowing in microchannel, allowing size-selective, label-free and high-throughput cell sorting. Firstly, high speed fluorescent microscope and confocal microscope will be employed to explore the fundamentals of inertial focusing which remains unclear. Parameters (e.g. flow rate) affecting inertial focusing positions and those related to separation-size resolution will be interrogated. Subsequently, biochips for CTC isolation will be fabricated, validated and optimized using fluorescent microparticles. Validation and further optimization of the high performance system will then proceed to CTC isolation using blood sample spiked with cancer cell (e.g. MCF-7) due to different properties between cells and particles. The proposed innovative device of single inertial microfluidic biochip is expected to permit high profiles of the critical parameters (throughput, efficiency, purity, sensitivity and viability) simultaneously and thus facilitate the implementation of CTC detection in clinical routine.