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Exosomes Characterization Services

Nanoparticle Tracking Analysis

Exosome and extracellular vesicles (EV) play important roles in a myriad of biological processes and are widely studied. Biological matrix, isolation and purification steps, heterogeneity of particles’ size make the characterization of exosome considerably complex for most techniques available on the market. Over the past few years, Nanoparticle Tracking Analysis (NTA) was found to be one of the most suitable and reliable technique for analysis of a variety of nanoparticles, and found to be exceptionally suitable for exosomes characterization.

NTA simultaneously identifies and tracks each individual particle moving under Brownian motion and relates movement trajectory to particle size. It results in exceptional capability to resolve and count particles of different size in the mixture.

Equipment: Nanosight  (Malvern), Zetaview (Particle Metrix GMBH).

Fluorescent Nanoparticle Tracking Analysis

fNTA allows detecting fluorescently labeled exosomes in the sample. This method is very useful for analysis of purity of exosome samples via labeling of an intact exosomal membrane with a fluorescent dye. The exosomes will be detected in fluorescent measurement mode of the instrument, while scatter mode will show total particle concentration and size. Proteins, lipid droplets, and other debris are common contaminants of exosome samples. Detecting fluorescently labeled exosomes helps to understand the purity and quality of the sample preparation. Another application of fNTA is labeling of exosomes with fluorescently labeled antibodies for phenotyping. With Zetaview Twin system we can detect two colors on the same sample.

Equipment: Nanosight  (Malvern), Zetaview, Zetaview Twin (Particle Metrix GMBH).

Electron microscopy​

Electron microscopy is widely used to image exosomes and study their structure and size. The most simple and common method for EM imaging of exosomes is negative staining with uranyl acetate or phosphotungstic acid. With this method, the exosomes are absorbed on a grid and then negative contrast is applied that stains the background while the exosomes appear light. Immunolabeling of exosomes can also be done with gold-labeled antibodies. The samples are imaged dry, thus exosomes often exhibit a cup-shaped morphology. TEM resolution towards the size of exosomes is higher compared to NTA and smaller particles can be detected. We have successfully used TEM to cross-validate the size distribution data from NTA with hundreds of particles measured and analyzed. 

Cryo electron microscopy is another powerful tool to study nanoparticles, including exosomes. The samples are frozen in liquid nitrogen and thus the shape and microstructure are preserved better compared to traditional TEM method. 

Exosomes Isolation Services

At Alpha Nano Tech we offer exosome isolation services from various biological fluids and tissues, including plasma, urine, saliva, cerebrospinal fluid, ascites fluid, cell-conditioned media and solid tissues. Isolated exosomes can be characterized by the full spectrum of methods available to us. The exosomes can be shipped back to the client if requested. 

Tunable Resistive Pulse Sensing (TRPS)

TRPS counts and measures particles as they pass a nanopore, as particles cross the pore they briefly increase electrical resistance, creating a resistive pulse, which is precisely proportional to particle volume. TRPS represents a rapid, convenient, accurate and reproducible method for nanoparticle analysis. 

Equipment: qNano (IZON)

Exosome RNA Analysis

Exosomes carry a variety of biomarkers that can differ depending on the origin of exosomes. Thus the analysis of RNA and  DNA content of exosomes gains a lot of interest. Our services include RNA isolation, Quantitation and QC, Library preparation, Sequencing, and data analysis and report. 

Exosome Protein Analysis

Our protein characterization services for exosomes include total protein content measurement, western blot, and proteomics.