Label-free Separation of Circulating Tumor Cells Using a Self-Amplified Inertial Focusing (SAIF) Microfluidic Chip

Abstract

Circulating tumor cells (CTCs) are rare cells existing in the bloodstream with a relatively low number, which facilitate as a predictor of cancer progress. However, it is difficult to obtain highly purified intact CTCs with desired viability due to the low percentage of CTCs among blood cells. In this work, we demonstrate a novel selfamplified inertial focused (SAIF) microfluidic chip that enables sizebased, high-throughput, label-free separation of CTCs from a patient's blood. The SAIF chip introduced in this study demonstrated the feasibility of an extremely narrow zigzag channel (with 40 μm channel width) connected with two expansion regions to effectively separate different-sized cells with amplified separation distance. The chip performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with three different types of cancer cells. The separation efficiencies for blood cells and spiked cancer cells are higher than 80%. Recovery rates of cancer cells were tested by spiking 1500 lung cancer cells (A549), breast cancer cells (MCF-7), and cervical cancer cells (HeLa) separately to 3 mL 0.09% saline with 3 × 10 6 white blood cells (WBCs). The recovery rates for larger cells (MCF-7 and HeLa) were 79.1 and 85.4%, respectively. Viabilities of the cells harvested from outlets were all higher than 97% after culturing for 24, 48, and 72 h. The SAIF chip performance was further confirmed using the real clinical patient blood samples from four lung cancer patients. Theoretical force balance analysis in physics, computational simulations, and experimental observations indicate that the SAIF chip is simple but effective, and high-throughput separation CTCs can be readily achieved without complex structures.

Microfluidic platforms for extracellular vesicle isolation, analysis and therapy in cancer

“…Dean flow fractionation and viscoelastic flow. Inertial microfluidic separation has been widely used to isolate CTCs [17][18][19][20] and bacteria 33,34 with simple manipulation and high-throughput, without the requirement of external applied forces, such as in electrophoretic and acoustophoretic systems. Although the inertial lift force is sufficient to laterally displace large particles, such as CTCs, within a microchannel, this force becomes trivial once the particles' dimension decrease to the nanoscale.…”

Integrated microfluidic single-cell immunoblotting chip enables high-throughput isolation, enrichment and direct protein analysis of circulating tumor cells

“…Detection of circulating tumor cells (CTCs) in the peripheral blood has the potential to be a powerful and noninvasive method for the early diagnosis of cancer invasion and metastasis, evaluation of prognosis, assessment of tumor cell sensitivity to anticancer drugs, and monitoring of therapeutic responses. Technologies have been developed based on the distinctive properties of epithelial CTCs and erythrocytes or leukocytes 1 , such as physical properties (size, weight, or density) [2][3][4][5][6] , flow, and elasticity characteristics [7][8][9][10] , and differential expression of biological factors 11,12 . However, simultaneous isolation and downstream molecular characterization of CTCs in the blood of clinical cancer patients remains a major challenge due to the heterogeneity and rarity of CTCs.…”

Ultrahigh SERS activity of the TiO2@Ag nanostructure leveraged for accurately detecting CTCs in peripheral blood

“…5 In recent years, many methods have been developed for detecting CTCs based on physical and chemical characteristics, such as size, density, charge, and photoacoustics, [6][7][8][9] which retain the bioactivity of CTCs, but the capture purity is low due to the interference of a large number of leukocytes. Immunomagnetic beads, 10 and microfluidic chips, 11,12 based on the specific binding between antigen and antibody have been reported with great potential in CTCs detection. The CellSearch system is a noted medical instrument for CTC detection approved by the U.S. Food and Drug Administration (FDA), which greatly promotes the application value of CTCs in liquid biopsy.…”