Liquid biopsy on chip: a paradigm shift towards the understanding of cancer metastasis

This comprehensive review serves as a guide for developing scalable and robust liquid biopsies on chip for capture, detection, and analysis of circulating tumor cells (CTCs). Liquid biopsy, the detection of biomarkers from body fluids, has proven challenging because of CTC rarity and the heterogeneity of CTCs shed from tumors. The review starts with the underlying biological mechanisms that make liquid biopsy a challenge before moving into an evaluation of current technological progress. Then, a framework for evaluation of the technologies is presented with special attention to throughput, capture rate, and cell viability for analysis. Technologies for CTC capture, detection, and analysis will be evaluated based on these criteria, with a focus on current approaches, limitations and future directions. The paper provides a critical review for microchip developers as well as clinical investigators to build upon the existing progress towards the goal of designing CTC capture, detection, and analysis platforms. This review provides a framework for development of on-chip liquid biopsy platforms for capture, detection, and analysis of circulating tumor cells.