Sensing surface tension for evaluating circulating tumor cell transiting behaviors at narrow vessels

Circulating tumor cell (CTC) transendothelial migration, a process starting from cell adhesion to vessel walls, is a critical process in tumor metastasis such that tumors become hard to be eliminated. Existing studies generally focus on CTC behaviors in normal blood vessels. However, considering the high incidence of tumor in elder population and the elevated vascular diseases predisposition in elderly patients, vascular abnormalities should be taken into account when studying CTC behaviors. Many vascular diseases cause abnormal narrowing of blood vessels, such as thrombosis. On the other hand, tumor cell mechanical properties are serving as label-free biomarkers for evaluating metastatic potential. This study is the first to identify that sensing surface tension could effectively evaluate CTC transiting behaviors in narrow regions, offering valuable insights into their transendothelial migration potential. We employed both finite element method simulations and microfluidic experiments to argue surface tension is a key mechanical biomarker for CTCs transiting around narrow regions. Additionally, we examined the effects of drug treatment on surface tension through sensing single cell surface tension values after Cytochalasin D treatment. We further observed cancer cell transiting behaviors in microfluidic experiments, of which results consist with simulations. Our findings highlight sensing surface tension is a novel and effective way for assessing CTC transendothelial potentials in narrow vessels, which is promising to become a label-free examination method in clinical tumor prognosis.