Integrated Microfluidics for Single-Cell Separation and On-Chip Analysis: Novel Applications and Recent Advances

From deciphering infection and disease mechanisms to identifying novel biomarkers and personalizing treatments, the characteristics of individual cells can provide significant insights into a variety of biological processes and facilitate decision-making in biomedical environments. Conventional single-cell analysis methods are limited in terms of cost, contamination risks, sample volumes, analysis times, throughput, sensitivity, and selectivity. Although microfluidic approaches have been suggested as a low-cost, information-rich, and high-throughput alternative to conventional single-cell isolation and analysis methods, limitations such as necessary off-chip sample pre- and post-processing as well as systems designed for individual workflows have restricted their applications. In this review, a comprehensive overview of recent advances in integrated microfluidics for single-cell isolation and on-chip analysis in three prominent application domains are provided: investigation of somatic cells (particularly cancer and immune cells), stem cells, and microorganisms. Also, the use of conventional cell separation methods (e.g., dielectrophoresis) in unconventional or novel ways, which can advance the integration of multiple workflows in microfluidic systems, is discussed. Finally, a critical discussion related to current limitations of integrated microfluidic single-cell workflows and how they could be overcome is provided.