Recent advances in droplet-based microfluidics in liquid biopsy for cancer diagnosis

Liquid biopsy, a noninvasive technique to obtain tumor information from body fluids, is an emerging technology for cancer diagnosis, prognosis, and monitoring, providing crucial support for the realization of precision medicine. The main biomarkers of liquid biopsy include circulating tumor cells, circulating tumor DNA, microRNA, and circulating tumor exosomes. Traditional liquid biopsy detection methods include flow cytometry, immunoassay, polymerase chain reaction (PCR)-based methods, and next-generation sequencing (NGS)-based methods, which are time-consuming, labor-intensive, and cannot reflect cell heterogeneity. Droplet-based microfluidics with high throughput, low contamination, high sensitivity, and single-cell/single-molecule/single-exosome analysis capabilities have shown great potential in the field of liquid biopsy. This review aims to summarize the recent development in droplet-based microfluidics in liquid biopsy for cancer diagnosis.