Microfluidic channel for characterizing normal and breast cancer cells

A microfluidic channel was designed and fabricated for the investigation of behaviors of normal and cancer cells in a narrow channel. A specific question addressed in this study was whether it is possible to distinguish normal versus cancer cells by detecting their stationary and passing behaviors through a narrow channel. We hypothesized that due to higher deformability, softer cancer cells will pass through the channel further and quicker than normal cells. Two cell lines, employed herein, were non-tumor breast epithelial cells (MCF-10A; 11.2  ±  2.4 µ m in diameter) and triple negative breast cancer cells (MDA-MB-231; 12.4  ±  2.1 µ m in diameter). The microfluidic channel was 300 µ m long and linearly tapered with a width of 30 µ m at an inlet to 5 µ m at an outlet. The result revealed that MDA-MB-231 cells entered and stuck further toward the outlet than MCF-10A cells in response to a slow flow (2 µ l min⁻¹). Further, in response to a fast flow (5 µ l min⁻¹), the passage time (mean  ±  s.d.) was 26.6  ±  43.9 s for normal cells ( N   =  158), and 1.9  ±  1.4 s for cancer cells ( N   =  128). The measurement of stiffness by atomic force microscopy as well as model-based predictions pointed out that MDA-MB-231 cells are significantly softer than MCF-10A cells. Collectively, the result in this study suggests that analysis of an individual cell's behavior through a narrow channel can characterize deformable cancer cells from normal ones, supporting the possibility of enriching circulating tumor cells using novel microfluidics-based analysis. (paper)