ZetaView NTA Particle Analysis Service
Analysis of microvesicles isolated from a biological sample requires the measurement of a range of parameters for characterization. A fundamental metric routinely measured in exosome research is the number and size distribution of exosome particles. Combining this measurement with the protein content of the sample can also provide a measure of sample purity.
The most widely used and accepted method for exosome size analysis is tracking of Brownian motion. Measurements of this kind were pioneered in the exosome and microvesicle field using Nanosight instruments.
Cell Guidance Systems exosome analysis service uses ZetaView®, a second generation particle size instrument from Particle Metrix which, thanks to the ease of use, provides higher throughput and greater economy, allowing us to deliver a highly cost-effective exosome analysis service.
The ZetaView® is a high performance integrated instrument for individual exosome particle tracking, classical micro-electrophoresis and Brownian motion.
Auto-alignment and auto-focussing capabilities make the ZetaView® both fast and easy to use. A throughput of >20 samples per hour can readily be achieved. Highly resolved zeta potential and size histograms, as well as profiles, are routinely derived from thousands of particles. In addition, low concentrations of particles can be determined.
The ZetaView® provides analysis certainty, leading to a better level of exosome characterization and enabling new discoveries in microvesicle and exosome research.
Concentration and particle counting
Prior to applying the exosomes to the Zetaview particle counter, the sample is diluted to 1500 μl to ensure adequate volume required for effective NTA performance. As a minimum concentration, 106 exosome particles per ml are needed. The maximum number of exosomes is 1010 particles per ml. For higher exosome concentrations, dilution or optical filtering is required. Against a background of other particle sizes, up to 1000 ppm of 200 nm sized particles have been measured.
Optional analysis of zeta potential
Zeta potential is a measure of the charge on a particle. If the particle is an aggregate, the charge will be closer to neutral than an organized biological structure. This is because aggregates are formed of smaller particles of varying charges which attract each other and diminish overall charge. If a particle moves rapidly under an electric field, it indicates biological structure. In contrast, aggregates move more slowly. Zeta potential is important for the analysis of exosomes because it provides information on the number of aggregates in a sample.