The newest member of bioactive vesicles, exosomes are identified with an outstanding ability to promote communication between cells. Exosomes are derived from the late endosomes and released into the extracellular environment through multivesicular body exocytosis. The property of exosomes that they can be internalized by recipient cells through endocytosis where the release of exosomal contents can trigger a variety of responses in the target cells has made them a groundbreaking research object, especially in the aspect of cancer and infectious diseases. However, it took a relatively long time for researchers to further investigate the roles that exosomes play in the micro-environment due to the lack of apposite methods to analyze these small subcellular structures.
The situation of exosome analysis and quantification takes a turn for the better with the emergence of nanoparticle tracking analysis (NTA) technology. Exosome NTA made these small exosomal contents visible in their naturally dispersed state for the first time, which has made a significant contribution to the understanding of the biological role of exosomes.
Before researchers can further investigate how exosomes involve in disease progression, they need to be isolated from the body fluids of patients using different techniques, such as ultracentrifugation, charge neutralization-based precipitation, gel filtration, or affinity purification. The specific technique is dependent on the requirement of yield, purity, reproducibility, quality, and downstream application. NTA provides an easy and fast way to check the size and concentration of the extracted exosomes after isolation, and fluorescence nanoparticle tracking analysis (F-NTA) using specific dyes can label definite exosomes and check their purity. Triple staining isolated exosomes with antibodies targeting CD9, CD63, and CD81 is a method to identify the size, concentration, and percentage of other exosomal fractions.
In addition, building and screening an immune antibody library for exosomes and biomarkers could be applied to profile and characterize specific exosomal protein compositions or track the origin of the isolated exosomes. Creative Biolabs is an eminent service provider of immune phage display antibody library screening. It has been dedicated to generating highly specific antibodies that target common exosome markers and disease-specific markers to facilitate the study of exosomal morphology and dynamics, as well as to help enlighten their roles in various disease therapies.
After isolation, purification, and other necessary processes, researchers can further look into the involvement and contribution of exosomes in a disease process based on different methods. Among these techniques, fluorescence nanoparticle tracking analysis is mostly used to analyze the quantity of protein candidates to determine the disease state or measure how a patient responds to treatment.
Several studies have expounded on the roles that exosomes play in different cancers. For example, by affecting drug resistance, immune modulation, or vascularisation, these bioactive vesicles are a key part of mediating tumor growth and metastasis. Exosomes can not only regulate cardiovascular diseases by intervening inflammation-related processes, but cause diabetes, neurogenerative, and respiratory diseases. Furthermore, for infectious diseases caused by bacteria, parasites, and viruses, exosomes can participate in intercellular communications and immune responses, which has aroused wide interest in developing infectious disease therapy based on exosomes. The basic logic is to interfere with the secretion of exosomes or viruses’ ability to package exosomes during infection, and with the acknowledgment of engineered exosomes, researchers further proposed that engineered exosomes with modified contents are likely to treat cancers and infectious diseases.
In general, exosomes are promising drug vehicles, in which artificial vesicles are easier to control, standardize, and produce in contrast to natural exosomes, though with a compromise of efficacy. For better safety and quality of synthetic exosome products, researchers are encouraged to draw support from NTA technology to analyze product concentration and purity as well as use F-NTA technology to monitor the drug loading process.