A microfluidic chip for immunocapture and quantification of circulating exosomes

Increasing attention has been attracted by exosomes in blood-based diagnosis because cancer cells release more exosomes in serum than normal cells and these exosomes overexpress a certain number of cancer-related biomarkers. However, capture and biomarker analysis of exosomes for clinical application are technically challenging.

In this study, researchers at Dalian Medical University developed a microfluidic chip for immunocapture and quantification of circulating exosomes from small sample volume and applied this device in clinical study. Circulating EpCAM-positive exosomes were measured in 6 cases breast cancer patients and 3 healthy controls to assist diagnosis. A significant increase in the EpCAM-positive exosome level in these patients was detected, compared to healthy controls. Furthermore, the researchers quantified circulating HER2-positive exosomes in 19 cases of breast cancer patients for molecular classification. They demonstrated that the exosomal HER2 expression levels were almost consistent with that in tumor tissues assessed by immunohistochemical staining. The microfluidic chip might provide a new platform to assist breast cancer diagnosis and molecular classification.

Chip design and principle for exosome capture and detection

(A) Schematic representation of the microfluidic chip. (B) Image of the chip. The scale bar represents 1 cm. (C) Workflow for the immunomagnetic capture and detection of exosomes.