Clinical application of a microfluidic chip for immunocapture and quantification of circulating exosomes to assist breast cancer diagnosis and molecular classification

Abstract

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, we 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, we quantified circulating HER2-positive exosomes in 19 cases of breast cancer patients for molecular classification. We 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.

Microfluidics for exosome isolation and analysis: enabling liquid biopsy for personalized medicine

“…In the simplest case, the sample is mixed and incubated with capture beads off-chip, so that only downstream bead separation, washing, and analysis steps take place on-chip. 57,76–78 For instance, Dudani et al . developed a microfluidic platform based on rapid inertial solution exchange (RInSE) that facilitated continuous-flow, high throughput, and 100% transfer efficiency of exosome capture beads from biofluids into a wash buffer.…”

“…Fang et al also employed immunocapture via magnetic beads, after which antibody-based fluorescence labeling was performed on chip to enable microscope-based imaging and quantification. 78 …”

Microfluidics‐based on‐a‐chip systems for isolating and analysing extracellular vesicles

“…Fang et al also used a fluorescent dye but instead used a microscope-based imaging system for detection [102]. In an alternative approach, Ko et al designed a smartphone-enabled portable on-a-chip optofluidic detection system, in which bead-captured EVs are recognised by a horseradish peroxidase-modified antibody.…”

Extracellular vesicles as emerging targets in cancer: Recent development from bench to bedside

“…Currently, microfluidic platforms are being actively developed and optimized for EV isolation and analysis. These devices are usually in a chip format and have built-in components for capturing EVs by filtration (214) or immunoaffinity (215, 216). In addition to isolating EVs, these devices have integrated components for further analysis of EVs.…”

“…In addition to isolating EVs, these devices have integrated components for further analysis of EVs. One of the integrated functions is the quantification of EVs (214, 216) since the number of EVs is an important biomarker of cancer. In addition, determining the content of EVs is also very valuable for diagnosis and prognosis, and microfluidic chips have been developed to profile the molecular markers carried by EVs by Hakho Lee and Ralph Weissleder.…”