Review: Microfluidics technologies for blood-based cancer liquid biopsies

Blood-based liquid biopsies provide a minimally invasive alternative to identify cellular and molecular signatures that can be used as biomarkers to detect early-stage cancer, predict disease progression, longitudinally monitor response to chemotherapeutic drugs, and provide personalized treatment options. Specific targets in blood that can be used for detailed molecular analysis to develop highly specific and sensitive biomarkers include circulating tumor cells (CTCs), exosomes shed from tumor cells, cell-free circulating tumor DNA (cfDNA), and circulating RNA. Given the low abundance of CTCs and other tumor-derived products in blood, clinical evaluation of liquid biopsies is extremely challenging. Microfluidics technologies for cellular and molecular separations have great potential to either outperform conventional methods or enable completely new approaches for efficient separation of targets from complex samples like blood. In this article, we provide a comprehensive overview of blood-based targets that can be used for analysis of cancer, review microfluidic technologies that are currently used for isolation of CTCs, tumor derived exosomes, cfDNA, and circulating RNA, and provide a detailed discussion regarding potential opportunities for microfluidics-based approaches in cancer diagnostics. Blood liquid biopsies yield various tumor derived products which can be effectively isolated using microfluidic approaches. These products have significant information that can help with a variety of assays to diagnose and monitor cancer. [Display omitted] •Blood based liquid biopsies provide unique opportunities for management of cancer.•Circulating tumor cells, exosomes and cell free nucleic acids provide important insights.•Microfluidics can accomplish efficient isolation of tumor cells and cell-derived products.•This review highlights blood-based liquid biopsies and their use in clinical decision making.