In Vivo Functional Services of Exosomes

Overview

Exosomes are a type of extracellular vesicles (EVs) secreted by various cells into the extracellular fluids. They are endogenous nanoparticles with a diameter ranging from 30 to 100nm and thus bypass elimination due to macrophages and neutrophils and show enhanced permeability and retention (EPR) effect termed as passive targeting. The vital role played by exosomes during physiological and pathological conditions has opened up remarkable opportunities for researchers in exosome-based drug delivery. Exosomes might serve as an effective drug carrier for disease treatment, superior to synthetic polymeric and lipidic nanoparticles which are associated with the high cost of production, reproducibility issue, toxicity, and triggering of the immune response. However, application of exosomes in site-specific drug delivery requires modification of the exosome surface by attaching a targeting ligand to reach the intended site of action and/or an imaging molecule for tracking exosomes and determining their biodistribution.

Exosome Labeling Methods for In Vivo Functional Research

Exogenously labeled exosomes are produced by first extracting them from cell culture medium via a suitable exosome extraction technique followed by decorating their surface with a fluorescent dye, exosome biotin labeling, or magnetic nanoparticle. While, endogenously labeled exosomes are produced by genetic engineering of exosome-producing cells with viral vectors expressing genes for GLuc, GFP, or mCherry.

Fig. 1 Different strategies explored for exosome surface modification. (Salunkhe, 2020)

Exosome Imaging Methods for In Vivo Functional Research

The selection of exosome imaging methods such as in vivo imaging system, flow cytometry, microscopy, immunohistochemistry, GLuc activity measurements, magnetic resonance, etc., depends upon the method of labeling and the objective of each study. Optical imaging (fluorescence and bioluminescence labeling) and radiolabelling are widely used techniques for carrying out imaging/tracking or biodistribution studies of exosomes. All of these techniques possess a distinctive advantage which can be used as a criterion for the selection of labeling method depending on the purpose of the tracking/imaging of exosomes.

Fig. 2 Imaging strategies for exosomes in vivo tracking. (Xu, 2021)

Applications

The surface-modified exosomes (SMEs) have been effectively used to determine their in vivo biodistribution by performing exosome tracking studies. Tracking/ imaging of exosomes in vivo helps in determining,

a) Their applicability as site-specific delivery vehicles.

b) Their roles in intercellular communication.

c) Their half-life.

Data so obtained guides the researchers to optimize/modify the exosome-based formulation strategy at an early stage thereby reducing cost, time, and resources associated with the entire production process. Biodistribution studies can be carried out by using exogenously or endogenously labeled exosomes.

Services at Creative Biolabs

Exosomal function researches by in vivo models are usually the most intuitive way. Focusing on exosome function research over years, Creative Biolabs has accumulated extensive experience and has established our own exosome function research in vivo models platform. Disease models construction service we can product include, but are not limited to:

In addition, we can also provide the most suitable exosome administration mode according to your needs. If you looking for a partner in exosome in vivo function research or you have any other questions about our services, please feel free to contact us for more information.

References

Salunkhe, S.; Dheeraj.; et al. Surface functionalization of exosomes for target-specific delivery and in vivo imaging & tracking: Strategies and significance. J Control Release. 2020, 326: 599-614.
Xu, M.; Feng, T.; et al. Engineered exosomes: desirable target-tracking characteristics for cerebrovascular and neurodegenerative disease therapies. Theranostics. 2021. 11(18):8926-8944.