Microfluidic iterative mechanical characteristics (iMECH) analyzer for single-cell metastatic identification

Abstract

This study describes the development of a microfluidic biosensor called the iterative mechanical characteristics (iMECH) analyzer which enables label-free biomechanical profiling of individual cells for distinction between metastatic and non-metastatic human mammary cell lines. Previous results have demonstrated that pulsed mechanical nanoindentation can modulate the biomechanics of cells resulting in distinctly different biomechanical responses in metastatic and non-metastatic cell lines. The iMECH analyzer aims to move this concept into a microfluidic, clinically more relevant platform. The iMECH analyzer directs a cyclic deformation regimen by pulling cells through a test channel comprised of narrow deformation channels and interspersed with wider relaxation regions which together simulate a dynamic microenvironment. The results of the iMECH analysis of human breast cell lines revealed that cyclic deformations produce a resistance in non-metastatic 184A1 and MCF10A cells as determined by a drop in their average velocity in the iterative deformation channels after each relaxation. In contrast, metastatic MDA-MB-231 and MDA-MB-468 cells exhibit a loss of resistance as measured by a velocity raise after each relaxation. These distinctive modulatory mechanical responses of normal-like non-metastatic and metastatic cancer breast cells to the pulsed indentations paradigm provide a unique bio-signature. The iMECH analyzer represents a diagnostic microchip advance for discriminating metastatic cancer at the single-cell level.

Biophysical phenotyping of cells via impedance spectroscopy in parallel cyclic deformability channels

“…As a result, the β time of the breast cancer cell line MDA-MB-231 is smaller than the β time of the normal breast cell line MCF-10A. In the ROC curve, we showed similar conclusions to our prior work; 8,15 we can reach a prediction ratio of 85.2% to identify cancer and normal cells if we rely only on the biomechanical properties.…”

“…13 Most of the studies on the mechanical properties of cell lines at the single-cell level have been carried out in a single constriction microfluidic channel, either with or without additional electrodes for impedance measurement. 2,[14][15][16] The impedance measurements obtained from cells within constriction channels can better identify the intrinsic biophysical properties of cancer cells 1,10,11 and can be used to distinguish cancer cell lines from normal cell lines at a single-cell level with an accuracy of >70%-95% at the population level. 10,17 Collection of biomechanical properties involves measuring transit times through video/image processing.…”

“…20 Video/image processing is commonly used to image cell movements in these constriction channels, which necessitates extensive image-processing time to obtain biomechanical information from the cell transit times. 8,15,21 Using the biomechanical and bioelectrical parameters directly measured from impedance spectroscopy can distinguish the cells with different dielectric properties. Sun's group used a single constriction channel with two electrodes to detect different cells.…”

Single-Cell Mechanical Characteristics Analyzed by Multiconstriction Microfluidic Channels

“…23–27 Metastatic cancer cells have softer cell membranes, as well as deformation ability in microfluidic constriction channels. On the other hand, normal cells have a cytoskeleton with higher mechanical strength, including but not limited to actin filaments, intermediate filaments, and microtubules.…”

“…On the other hand, normal cells have a cytoskeleton with higher mechanical strength, including but not limited to actin filaments, intermediate filaments, and microtubules. 23,28,29 Therefore, the deformation time of cancer cells and normal cells has been shown to differ due to their mechanical properties. Many studies have focused on the entry time and transit time of cells in a constriction channel, and analysis has defined criteria typifying specific cell lines.…”