Particle Metrix, developers of versatile particle characterization solutions for the life sciences, report on the work of the Baur Laboratory in the Department of Dermatology at the University Hospital of Erlangen. The Group, which is part of the Translational Research Center at the University, is working to quantify extracellular vesicles in plasma of patients.
Andreas Baur leads a group in the Department of Dermatology at the University Hospital of Erlangen. Their research focuses on the quantification of extracellular vesicles (EV) in plasma of patients. The group has used several different approaches as recently demonstrated in their paper published in EBioMedicine1 (03/2016). This reported on the quantification of EV-derived microRNA, the measurement of protein concentration in sucrose fractions that contain EV and the measurement of particles in sucrose gradient fractions. This work has been performed using the ZetaView system from Particle Metrix. Used together, these parameters provide a rough estimate on the relative concentration of EV in plasma.
The Baur group chose the ZetaView system for microparticle characterization because it is the only way to get actual numbers of nanoparticles in a given solution. All other measuring methods are semi-quantitative at best. However, it is advisable to consider particle measurements not as absolute numbers unless serial dilutions have been made and measured and different patient samples have been compared and, these again have to be in a comparable range of particle numbers.
Prior to using ZetaView, they did not use any EV quantification tool/device, but rather measured the concentrations indirectly as outlined above. As principle user of the system, Jochen Dindorf, says, “ZetaView is the only way to get actual particle numbers, rather than a semi-quantitative assessment of EV in a given solution, e.g. by western blot or RNA quantification. I also find it an easy instrument to teach new users how to use. This is really useful for our lab.”
ZetaView allows the measurement of quantitative information on the number of particles in a particular preparation as well as basic physical information (i.e. size and zeta potential)
After successfully showing C-NTA of double-stained MSC-EVs in our previous study (https://bit.ly/43GG0Yk) and confirming
the results with image flow cytometry, this note describes C-NTA of multi-stained MSC-EVs using a PMX-430 QUATT NTA
system with four lasers.
In this new application note we describe a quick determination of the physical titer of coronaviruses by fluorescence-based Nanoparticle Tracking Analysis and specific spike antibody recognition.
In this report, we describe the quantification of colocalization ratios on double-stained MSC-derived EVs using fluorochrome conjugated antibodies against the
cell surface antigens CD9 and CD41, which also serve as EV marker proteins.
In addition to using Nano Particle Tracking Analysis (NTA) to measurement the size distribution and concentration of EV samples, both Microfluidic Resistive Pulse Sensing (MRPS) and the Single Particle Interference Reflectance Image Sensor (SP-IRIS) methods have been widely used as an alternative means of characterizing EVs. In this note, we relay two specific cases for using the ZetaView® NTA system to achieve relative “high-throughput” analysis of many EV samples, along estimations of throughput for MRPS & SPIRIS methods for an equivalent number of samples; further, we establish realistic estimates for the high cost of ownership for operating MRPS & SP-IRIS systems as a result of the cost of consumables as well as the substantially greater amount of time spent to run the same number of samples.
Along with generally accepted methods are some “tricks of the trade” such as the addition of Tween® or BSA; however, some of those additions are problematic.
Determination of the titer of viruses and bacteriophages is an indispensable key technology in virological research and for diagnostic purposes. Depending on the method used, the measurements are either qualitative or quantitative, very time-consuming, and do not provide information about integrity or aggregation behaviour of the virus particles. Nanoparticle Tracking Analysis with the Particle Metrix ZetaView® instrument allows the user to perform a rapid concentration determination of virus particles. Using the bacteriophage Phi6 as an example, we show how titer, purity and integrity of phage particles can be measured quickly and reliably using the fluorescence detection capability of the Particle Metrix ZetaView® instrument.
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