Abstract

Phenotyping Extracellular Vesicles Using Tetraspanins and Fluorescence-NTA

Ross Jacobson, Technical Sales, Particle Metrix

Nanoparticle Tracking Analysis (NTA) measures size and concentration of nanoparticles in the size  range  from  10  nm  to  1  µm.  While  getting  a  particle  size  distribution,  the  user  typically cannot  discriminate  whether  the  particle  is  a  vesicle,  protein  aggregate,  cellular  trash  or  an inorganic  precipitate  from  scatter  data  alone.  The  fluorescent  detection  capability  of  NTA enables the user to gain biochemical information about the particle and increases the resolution and the discrimination power. NTA instruments traditionally are equipped with one laser wavelength in operation. This limits the detection of biomarkers to only a couple fluorescence dyes. To expand the number of excitation wavelengths, it was necessary to change of the laser  source,  a  time  and sample  consuming  step.  To  overcome  this  issue  Particle  Metrix developed a unique QUATT laser technology and now allows the rapid analysis of biomarker concentrations or ratios with four excitation lasers on the same sample.  Here we report the quick and easy EV Phenotyping via multi-wavelength f-NTA on the new Particle Metrix four laser system. Alignment-free switching   between excitation wavelengths and   measurement mode (scatter and fluorescence) allows quantification of biomarker ratios such as Tetraspanins (CD63, CD81, CD9 and CD41) on the same sample within minutes reducing measurement time and precious sample volumes.