Microfluidic capture and spatiotemporal analysis: Chemical mechanisms of tumor exosome-mediated malignant cell transformation.

Tumor metastasis is the primary cause of death from malignant tumors. The elucidation of its molecular mechanism is of great significance for breakthroughs in targeted therapy. In this study, a microfluidic chip platform integrating "dynamic dilution-precise capture-mechanical stimulation-in situ analysis" was constructed. Through the design of bionic narrow channels, efficient separation of exosomes and functional research at the single-cell level were achieved. On the one hand, the mechanical microenvironment within the chip was utilized to regulate the secretion of tumor cell exosomes (increasing secretion levels by more than twofold) and the expression of key proteins, revealing the exosome-mediated cell invasion behavior. On the other hand, using breast cancer as a model, the malignant transformation effects of exosomes derived from highly metastatic MDA-MB-231 cells and low-metastatic MCF-7 cells on normal MCF-10A breast epithelial cells were comparatively analyzed. The transformation efficiency was preliminarily verified using the CD43 (a marker associated with malignant transformation), and the reasonable inference was established regarding the regulatory role of PD-L1 in the epithelial-mesenchymal transition (EMT) process. Experiments were then conducted on whole blood samples (processing time for 0.5 mL whole blood <10 min). The study provides new potential targets and intervention strategies for cancer immunotherapy.