Microfluidic chip for rapid and selective isolation of tumor-derived extracellular vesicles for early diagnosis and metastatic risk evaluation of breast cancer

The epithelial-to-mesenchymal transition (EMT) index in cancer is a complementary approach for estimating metastatic risk. Considering the demand for evaluating metastatic risk based on liquid biopsies, tumor-derived extracellular vesicles (EVs) can be exploited to generate the EMT index. For the generation of EVs-based EMT index, it is essential to selectively isolate each epithelial cell and mesenchymal cell-derived EVs. This study proposes a novel microfluidic chip for selectively separating two types of EVs in an efficient and timely manner. The microfluidic chip is fully integrated with a micromixer for the creation of efficient collision between EVs and specific antibody-coated microbeads (7 and 15 mu m in diameter) and a hydrodynamic particle separator for the stratification of EVs bound microbeads according to the sizes of microbeads. Using this chip, over 90% of EVs expressing the epithelial marker (epithelial cell adhesion molecule, EpCAM) and the mesenchymal marker (CD49f) can be selectively isolated within 6.7 min per 100 mu L of sample volume. The clinical relevance of EMT is investigated using plasma samples from 20 breast cancer patients and 10 age-matched controls. The EMT index produced from the microfluidic chip is in a good agreement with the conventional tissue-based EMT index and is significantly high in patients with aggressive breast cancer subtypes, compared with healthy controls. In addition, the patients with high scores on the EMT index (>= 5) shows recurrence within 5 years after adjuvant treatment. Predicting EMT-index-based metastatic risk using our microfluidic chip can be beneficial for cancer diagnosis and prognosis.

Automated summary

A novel microfluidic chip was used to selectively isolate epithelial and mesenchymal cell-derived EVs, generating an EMT index for investigating the clinical relevance in breast cancer patients. The EMT index produced from the chip showed good agreement with the conventional tissue-based index and was significantly higher in patients with aggressive subtypes. Patients with high EMT index scores (>= 5) were more likely to experience recurrence within 5 years post-treatment. Prediction of metastatic risk based on the EMT index using the microfluidic chip could be beneficial for cancer diagnosis and prognosis.