Microfluidic systems are transforming cancer diagnostics by enabling precise, label-free isolation of circulating tumor cells (CTCs) from blood samples. CTCs are among the most important biomarkers in breast cancer diagnosis, yet they exist in extremely low concentrations—often just a few cells per milliliter of blood—making their isolation technically challenging. As a result, CTC detection is emerging as a powerful, non-invasive alternative to traditional tissue biopsies.
Several methods have been developed to isolate CTCs, but microfluidic technology stands out as a promising platform for both chemical and physical separation of CTCs from whole blood. Due to their unique size, shape asymmetry, and mechanical properties, CTCs can be selectively separated using microfluidic channels. However, these cells are also vulnerable to shear forces, which may damage them during the isolation process—highlighting the importance of optimized microchannel design for gentle, high-purity cell capture.
A new elasto-filtration microfluidic device, based on the critical elasto-capillary number, selectively captures CTCs by optimizing multiple physical parameters—such as cell size, pore diameter, cell elasticity, and hydrodynamic forces—while efficiently depleting white blood cells (WBCs).
Dielectrophoresis (DEP) is emerging as a powerful electrokinetic technique for CTC isolation. Unlike antibody-based methods, DEP leverages the natural dielectric properties of cells, offering marker-free separation and maintaining CTC viability for downstream analysis or culture.
Recent advancements in microfluidic electrochemical sensors allow low-cost, high-speed breast cancer detection by analyzing the dielectric behavior of cancer cells. In parallel, magnetic separation techniques using microbeads have become standard for cell sorting in tissue engineering and clinical research, offering efficient and scalable solutions.
Mechanical, electrical, magnetic, and acoustic microfluidic platforms continue to evolve, enabling high-throughput, automated cell sorting. While optical methods have been less explored due to system complexity, new optofluidic techniques using red blood cell (RBC)–conjugated CTCs and laser-based sorting have shown promising results with high purity and gentle cell handling.
These emerging microfluidic CTC isolation technologies are paving the way for next-generation liquid biopsy, early cancer detection, and personalized therapy monitoring.
source: https://pmc.ncbi.nlm.nih.gov/articles/PMC8877872/#sec3-micromachines-13-00152
