Application of label-free techniques in microfluidic for biomolecules detection and circulating tumor cells analysis

Circulating tumor cells (CTCs) are an important biomarker for various types of cancers. As CTCs are extremely rare in the bloodstream, the accurate analysis and efficient separation of CTCs is a challenging task. In order to develop new diagnostic approaches for cancer research, understanding the functional characteristics of biomolecules at the single-molecule level in individual cancer cells is required. Meanwhile, microfluidic platforms have emerged as a promising technology for analyzing single molecules and single cells. In this review, we discuss some label-free techniques for biomolecule detection and highlight some reports that have employed combined label-free techniques with microfluidics for individual molecule or cancer cell analysis. Finally, we offer our perspective of the integration of label-free techniques with microfluidic technology on future applications.