Exploiting Microfluidics for Extracellular Vesicle Isolation and Characterization: Potential Use for Standardized Embryo Quality Assessment

Abstract

Recent decades have seen a growing interest in the study of extracellular vesicles (EVs), driven by their role in cellular communication, and potential as biomarkers of health and disease. Although it is known that embryos secrete EVs, studies on the importance of embryonic EVs are still very limited. This limitation is due mainly to small sample volumes, with low EV concentrations available for analysis, and to laborious, costly and time-consuming procedures for isolating and evaluating EVs. In this respect, microfluidics technologies represent a promising avenue for optimizing the isolation and characterization of embryonic EVs. Despite significant improvements in microfluidics for EV isolation and characterization, the use of EVs as markers of embryo quality has been held back by two key challenges: (1) the lack of specific biomarkers of embryo quality, and (2) the limited number of studies evaluating the content of embryonic EVs across embryos with varying developmental competence. Our core aim in this review is to identify the critical challenges of EV isolation and to provide seeds for future studies to implement the profiling of embryonic EVs as a diagnostic test for embryo selection. We first summarize the conventional methods for isolating EVs and contrast these with the most promising microfluidics methods. We then discuss current knowledge of embryonic EVs and their potential role as biomarkers of embryo quality. Finally, we identify key ways in which microfluidics technologies could allow researchers to overcome the challenges of embryonic EV isolation and be used as a fast, user-friendly tool for non-invasive embryo selection.

Methodologies to Isolate and Purify Clinical Grade Extracellular Vesicles for Medical Applications

“…The specificity of the method is related to the specificity of antibodies that are immobilized on the chip [ 23 , 94 , 95 ]. As mentioned before, antibodies can be loaded on the beads located on the inner surface of the microchannel [ 96 ]. To reach the mentioned specificity, Exochip has been developed recently and due to the anti-CD68 antibodies (conjugate with CD68 that is expressed on the exosomes are released via various cell types) that are fixed on the microfluidic chips, the specific EV are isolated [ 23 , 97 ].…”

Recent Advances in Device Engineering and Computational Analysis for Characterization of Cell-Released Cancer Biomarkers

“…Outlook. With the advent of a new generation of technologies using micro and nanofluidics and materials, the isolation of sEVs has become notably more efficient [ 167 , 168 , 169 , 170 ]. Furthermore, as researchers are exploring the roles of cell type-specific sEVs, the ability to isolate TDEVs is beginning to transform our understanding of their physiological role in a disease setting.…”

Extracellular vesicles in urological malignancies

“…Precipitation also generates a high yield of EVs; however, this can be contaminated with protein aggregates and other lipid based molecules. More recently, microfluidic devices have been developed to isolate EVs from a range of suspensions including cell culture media, plasma and urine [ 211 ]. These devices are diverse and make use of the EV size, EV density and surface antibodies to separate them from their suspension as they flow through the device.…”