Monitoring the mechanical responses of tumor metastasis based on a microfluidic chip integrated with an electrochemical detection system.

Monitoring the mechanical responses of tumor cells during migration is crucial for understanding the mechanisms of tumor metastasis. Current studies on cellular mechanical responses primarily utilize microscopic observation techniques, while real-time monitoring cellular responses remains limited. In this work, we present a microfluidic tumor migration chip that incorporates electrochemical impedance spectroscopy to study the mechanical responses of tumor cells. Based on this platform, the impacts of spatial confinement and fluid shear stress on the morphology and migratory capacity of breast cancer tumor cells were evaluated in detail, and it was demonstrated that the morphology, migratory velocity and migratory mode of tumor cells are concurrently modulated by these two mechanical factors. Specifically, moderate spatial confinement and fluid shear stress have been observed to promote the migration of tumor cells and affect the change of their migration mode. Furthermore, electrochemical impedance spectroscopy was employed to evaluate the impedance change of tumor cells under different mechanical stimulation. Based on this detection system, not only the number of migrating cells within the microchannels can be quantified, but the transition of MDA-MB-231 cells to an amoeboid migration mode under tight spatial confinement, as well as the elongation of the cell morphology and transition to a mesenchymal mode due to fluid shear stress, can also be characterized. This platform demonstrates the feasibility of real-time monitoring of cell changes in response to mechanical stimuli, and offers a valuable tool for elucidating the mechanisms underlying cell invasion.