Purification-free lentivirus and exosome characterization
Complete lentivirus and exosome characterization
Soluble p24 contamination
- Cargo detection
- Custom biomarker detection
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Measure the particles you care about with our unique microarray chips. Specifically designed to capture either lentivirus or exosomes without the need for purification, our chips ensure contaminants don’t get in the way even in the crudest samples.
Our chips don’t just capture particles, their SiO2 coating is designed to unleash the power of single particle interferometry, providing particle diameters down to the nm. Add in an immuno-fluorescent stain and you’ve got size, concentration and phenotype all in one place.
LentiView chips immuno-capture viruses using highly specific antibodies immobilized on the chip surface.
Anti VSV-G spots bind viral envelope proteins to immobilize the virus on the spot which can then be probed internally to determine if the virus contains p24 capsid. The p24 capture spot provides quantification of soluble protein which is used to measure viral titer. Tetraspanin antibody spots also offer exosome contamination detection.
Our standard exosome chips feature CD9, CD63, CD81 and CD41a antibodies to capture all exosome related vesicles. Need a different antibody? Custom populations can be captured with our user customizable Flex chips.
Automated chip handling
Once the sample has been loaded onto the chip you can relax while the CW100 chip washer automates sample washing, drying and incubation. The automated process reduces hands-on time and removes user variability to increase throughput and consistently produce high quality data.
Get quick and accurate titer of intact, capsid containing virus. Separate fragments and empty virus from payload containing particles. Cut down on lengthy transduction assays and monitor titer throughout your purification process with no prior purification required.
Size & aggregation
Once the virus has been captured on the chip, viruses can be sized on a virus-by-virus basis. Separate size profiles can be obtained for the intact, capsid containing population and for empty virus.
Once bound to the surface of the LentiView chip, viruses are fixed and probed for the presence of VSV-G and p24 capsid protein using immunofluorescence staining. The resulting fluorescence image reveals VSV-G-positive viral particles devoid of capsid (empty) and colocalized VSV-G-positive and p24 positive viral particles (intact).
Soluble p24 contamination
Don't let soluble p24 blind you. LentiView can quantify soluble p24 and virally associated p24 separately allowing you to monitor removal of free protein throughout purification and focus on the functional capsid. The major limiting factor of the commonly used p24 ELISA assay is the assumption that the concentration of p24 protein in a preparation is proportional to the quantity of virus. p24 protein is relatively abundant in free solution, resulting in inaccurate virus titers. It also fails to discriminate full, intact virus from viral fragments or other particles containing p24.
Most lentivirus purification processes fail to remove exosome contaminants due to their similarity in size and density. Regulators, including the FDA, are increasingly aware of the need to monitor these non viral particles, making it vital that you know exactly what’s in your sample.
By combining LentiView with our fluorescent tetraspanin antibodies you can easily and directly measure the concentration of exosome contaminants in your viral sample.
Exosomes captured on each antibody spot can be analyzed, providing the concentration of exosomes that express the protein of interest. The concentration of exosomes expressing specific surface markers can be determined with a linearity of 5x105 to 1x108 particles/mL. Exosomes can be accurately quantified across 2.8 log orders and at concentrations at least 10x lower than is possible with NTA, which is 100-100,000x more sensitive than ELISA and western blots.
ExoView uses single particle interferometry to perform high resolution sizing of exosomes down to 50 nm. Particle subpopulations can be analyzed in aggregate, or at the single biomarker level.
Exosome subpopulations can be characterized by their protein profile and relative protein expression. ExoView biomarker colocalization analysis provides the ability to fully analyze exosome subpopulations and investigate the relationship between biomarker expression and disease state.
MISEV guidelines recommend that cytosolic proteins should be measured alongside common tetraspanin markers when characterizing exosomes. With our cargo assay, you can probe for internal and external targets simultaneously on the same vesicle. This allows you to both quantify the number of cargo containing particles and determine the relative amount of target protein per particle.
Custom biomarker detection
ExoFlex chips enable users to create custom assays, using RabMAbⓇ from AbcamTM, that specifically capture and detect extracellular vesicles that express any biomarker of interest. This unique technology allows sensitive detection of rare events in biomarker discovery and detection. In addition, multiplexed ExoFlex chips allow for antibody candidates to be rapidly screened.