From Conventional to Microfluidic: Progress in Extracellular Vesicle Separation and Individual Characterization

Abstract

Extracellular vesicles (EVs) are nanoscale membrane vesicles, which contain a wide variety of cargo such as proteins, miRNAs, and lipids. A growing body of evidence suggests that EVs are promising biomarkers for disease diagnosis and therapeutic strategies. Although the excellent clinical value, their use in personalized healthcare practice is not yet feasible due to their highly heterogeneous nature. Taking the difficulty of isolation and the small size of EVs into account, the characterization of EVs at a single‐particle level is both imperative and challenging. In a bid to address this critical point, more research has been directed into a microfluidic platform because of its inherent advantages in sensitivity, specificity, and throughput. This review discusses the biogenesis and heterogeneity of EVs and takes a broad view of state‐of‐the‐art advances in microfluidics‐based EV research, including not only EV separation, but also the single EV characterization of biophysical detection and biochemical analysis. To highlight the advantages of microfluidic techniques, conventional technologies are included for comparison. The current status of artificial intelligence (AI) for single EV characterization is then presented. Furthermore, the challenges and prospects of microfluidics and its combination with AI applications in single EV characterization are also discussed. In the foreseeable future, recent breakthroughs in microfluidic platforms are expected to pave the way for single EV analysis and improve applications for precision medicine.

The biological role of extracellular vesicles in gastric cancer metastasis

“…Accurate identification, isolation, and purification of EVs remain challenging and require further development of technologies and methods ( Wu et al, 2021 ). The emerging methods of EVs separation based on size and charge, as well as single EV analysis techniques in recent years, may help to address these issues ( Ko et al, 2021 ; Zhang et al, 2023b ; Chen et al, 2023c ). Third, despite extensive studies on the roles of EVs in tumors, the specific mechanisms of action of EVs, especially the signaling pathways, are still not fully understood.…”

Recent Advances in Microfluidic-Based Extracellular Vesicle Analysis

“…Furthermore, no requirements for optical transparency expand the choice of materials in electrochemical response. However, contamination and changes in pH, temperature, and ionic concentration often influence the lifetimes of electrodes, which needs to be addressed [75]. So far, only a limited number of microfluidic devices incorporated with electrochemical techniques have been developed for EV detection.…”

“…Surface enhanced Raman spectroscopy (SERS) effectively generates spectra on certain metal surfaces, providing vibrational and rotational energy information of molecules, which is reflected in spectral peaks used to specifically identify molecules [75,76]. However, SERS measurements present significant challenges in reproducibility and sensitivity [76].…”

Recent Advances in Microfluidic-Based Extracellular Vesicle Analysis

“…Furthermore, no requirements for optical transparency expand the choice of materials in electrochemical response. However, contamination and changes in pH, temperature, and ionic concentration often influence the lifetimes of electrodes, which needs to be addressed [85]. So far, only a limited number of microfluidic devices incorporated with electrochemical techniques have been developed for EV detection.…”