<br/>Extracellular vesicles (EVs) are cell-derived membranous vesicles that exist in nearly all biological fluids including blood, urine and cell culture media. Exosomes carry diverse cargos such as protein, DNA, mRNA and lipids and play pivotal roles in intercellular information transmission. But their small sizes and low copy numbers of the cargo molecules per vesicle make their analysis very challenging. Our group has developed multiple methods that allow the EV surface proteins to trigger signal amplification from nanostructures so that they can be detected at low concentrations in biospecimen like serum. One of the approaches is to amplify the size of individual EV by DNA nanostructures so that they can be analysed in conventional flow cytometers. In this approach, either an aptamer or an antibody is employed to recognize the specific surface marker on each EV, and initiate construction of a large DNA nanostructure by hybridization chain reaction. The resultant structure not only enlarges the overall size of the single EV, but also can bind to multiple fluorophores to amplify the signal from the few number of molecules locating on the EV surface. Both enable visualization of single EVs in a conventional flow cytometer. By far, we have successfully demonstrated counting single EVs in the FACSCanto after a one-pot reaction, and multiple surface markers can be simultaneously targeted to differentiate EV sub-groups based on their surface protein signature. We have been applying this technique to analyse EVs produced from different breast cancer cell lines, as well as the EVs in patients’ sera. On the other hand, we also constructed microgel particles encapsulating nanoparticles to help with both EV isolation and detection. In this approach, we employed the CuS enclosed microgel particles that help remove EVs from biofluids and carry thousands of metal ions to induce chemiluminescence for EV quantification based on their surface proteins. Overall, we have developed sensitive methods to analyse EVs in circulation system with high simplicity, which will help improve study of EVs’ capability being the effective liquid biopsy tool for disease diagnosis and prognosis.

Analysis of extracellular vesicle (EV) enabled by nanostructures

2019 Fall National Meeting

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