Virus Quantification using Spectradyne's nCS1TM and ARCTM

virus webinar

Quantitative fluorescence combined with MRPS particle sizing of virus

We've used the ARC to quantitatively measure the fluorescent labeling of adenovirus, using the ARCTM particle analyzer. These measurements were performed in a complex heterogenous sample, as described below.

The figure shows simultaneous particle sizing using MRPS and quantitative measurements of fluorescence, measurements made of EVs and adenovirus both together and in isolation. These data, which are discussed in more detail in this application note, demonstrate that the ARC quantitatively measures nanoparticle size, concentration, and internal payload fluorescence for virus and nanomedicine applications, and accurately analyzes fluorescent subpopulations, even in complex, heterogeneous samples.

fluorescent EVs

Accurate Viral Titer in Minutes

Conventional methods for quantifying virus such as live biological titer can take days to return results. The modern fast pace of research and current examples such as COVID-19 necessitate faster measurements. Researchers in many areas of virus research including basic virology, gene therapy, and epidemiology are looking for more modern approaches for measuring virus.

Spectradyne's nCS1TM and the fluorescent-detecting ARCTM deliver accurate viral particle counts in just a few minutes using microfluidic resistive pulse sensing (MRPSTM), which in the ARC is coupling with particle-by-particle fluorescence detection. The technology is fast, easy to adopt and employs disposable microfluidic cartridges for analysis — and it only requires a few microliters of your precious sample for analysis.

nCS1TM key features for virus quantification:

  • Total virus particle count in minutes
  • Disposable analysis cartridges — no laborious cleaning
  • Only uses 3 microliters sample required
The ARCTM adds individual particle fluorescence, with fluorescence quantified using NIST-traceable standards.


Read our two-page brochure on quantifying virus titer using Spectraydne's nCS1TM

Which technology is right for me?


Fast & accurate particle analysis with MRPS


MRPS plus single-particle fluorescence phenotyping

How big is your virus?

Virus come in a large range of different sizes and shapes. Some, such as the hepatitis and parvovirus, are roughly spherical and less than 50nm in diameter; some, such as the virus that causes Ebola, are long flexible cylinders with lengths as large as 1 μm; and some are spherical and of intermediate sizes, in the range of 75-300 nm in diameter.

In the figure below, we display a chart showing the size and shape of a range of different virus (chart obtained from Expasy).

virus chart

Spectradyne's nCS1TM can measure particles such as virus down to diameters less than 50nm and up to 10 μm in diameter. Contact us today if you're interested in finding out more.


"We eagerly purchased Spectradyne's current MRPS technology for the value it delivers in therapeutic retroviral quantification. We have been impressed with the results it delivers and how practically it fits with our industrial process flow..."

PhD scientist, Gene Therapy Co. Inc.

Better science

For measuring the infectivity of viruses, testing the immunogenicity of different viral preparations, and almost any down-stream analysis, accurate virus concentration measurements are critical for performing well-controlled experiments.

A retroviral drug product was serially diluted and the concentration measured as a function of size showing the excellent concentration linearity of the nCS1TM:

virus dilution

Serial dilutions of a retroviral drug product accurately quantified by Spectradyne's nCS1TM.

More and more researchers are choosing the nCS1TM for virus quantification because it is fast and easy to use and delivers a more accurate analysis of their virus samples than they can obtain using any other method.

Read more about virus and Spectradyne's technology

Here's a list of documents you might be interested in reading or viewing:

  • [PDF] Virus measurements and virus titer with Spectradyne's nCS1: A two-page brochure describing how to measure LNPs, with sample measurement results
  • [PDF] An overview of how Spectradyne's unique microfluidic technology is applied to nanoparticle analysis
  • [PDF] Basic concepts and implementation for using resistive pulse sensing (aka Coulter counting) in a microfluidic format

Measure your samples now!

For more information and for how to set up a measurement,
send an email to or contact us here.

Higher purity of viral preparations

Accurate and high-resolution particle concentration measurements enable direct quantification of the purity of virus preparations. Because the nCS1TM measures all types of particles in the sample, it can be used to quantify impurities and other non-viral particles in a given preparation.

The figure below shows measurements of a virus preparation at progressive stages of purification. Clearly purification step 2 significantly enriches for the target virus, as evidenced by the peak in the size distribution.

virus enrichment

Quantitative analysis of sample purification steps using the nCS1TM enable better informed decisions and speed up R&D.

Measurement examples

Customers use the nCS1TM to characterize a broad variety of viruses, including:

  • Lentivirus
  • Adenovirus
  • Adeno-associated virus aggregates
  • Bacteriophage (PR-772, T4, T3, L-VIR)
  • Influenza A, B (FluA, FluB)
  • Rabies
  • Herpes Simplex Virus (HSV)
  • Human Immunodeficiency Virus (HIV)
  • Murine Leukemia Virus (MLV)
  • Mouse Hepatitis Virus (MHV)
  • Myxoma Virus

Check out our blog page on interesting virus measurements made with the nCS1TM here

We have detailed measurements on a number of different virus targets. These include measurements of a myxoma virus, a brick-shaped virion of about 200 nm to 300 nm in diameter. In one example these were tested in a cell culture medium with little sample preparation. The nCS1TM was easily able to detect the virus population at 260 nm, even with a high concentration culture media background. Another example is where the nCS1TM was used to measure both a wild-type flu B virus (WT) and a mutant form. A third example is provided by a measurement of maraba virus, which is reported by TEM to have a cylindrical diameter of ~65 nm and a length of ~180 nm. You can read more about these measurements on our blog page here.

Your virus not in this list? Email us to learn more or Send us a sample!

Interested in pricing?

Send an email to or
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Spectradyne's nCS1TM delivers the most accurate concentration and size measurements of virus available in a practical bench top solution. The nCS1TM is fast and easy to use, and requires only 3 microliters of your sample to help you do better viral science. Contact us today for a free sample measurement or to request a demonstration!

Read our virus application note,
or send an email to

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