Microfluidics Technology for Label-Free Isolation of Circulating Tumor Cells

Abstract

Circulating tumor cells (CTCs) are the tumor cells that get detached from a primary tumor site and enter bloodstream circulation that promotes the metastasis condition of cancer. The detection and analysis of CTCs hold significant clinical and research value in terms of cancer diagnosis, prognosis, treatment, and drug development research. Isolation and analysis of CTCs are already proven as a promising tool for effective drug screening. CTCs in the circulation can be considered as biomarkers for the early-stage detection of cancer. CTCs also offer the opportunity to study, monitor, and ultimately gain insights into the process of cancer metastasis. Among the existing approaches, microfluidic technology has become a hot spot in CTC detection and isolation due to their promising features such as automation, high precision, accuracy and sensitivity, portability, that are amenable to the development of point-of-care devices. CTCs can be isolated from the blood by labeling the cells with tumor-specific biomarkers, but the use of chemicals for labeling may interfere with the downstream assay. This paper aims to review the label-free microfluidic techniques for the detection and isolation of CTCs that have the potential to preserve phenotypic and genotypic characteristics of isolated cells. The principle of operation, methodology, application, advantages, and limitations of the different techniques are discussed. The performance of the different techniques is assessed based on several parameters such as capture efficiency, throughput, purity, sensitivity, and cell viability. Finally, a brief discussion on the challenges, commercialization aspects, and future perspectives is presented.