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A mass photometer for AAV analytics


The Refeyn SamuxMP is a mass photometer optimized for adeno-associated virus (AAV) characterization and is an essential analytical tool for laboratories working with AAVs. SamuxMP mass photometry measurements are quick and require very little sample.

The SamuxMP precisely measures the empty/full capsid ratio for AAVs of any serotype as well as the quantities of partially filled and overfilled capsids. It can also detect impurities and aggregation, and give a rough capsid titer estimate as part of the standard data analysis procedure.  

  • Quantitative characterisation of AAVs of all serotypes

  • Easy measurement of empty / full ratio of AAV capsids

  • Rapid analysis requiring minimal sample

  • User-friendly operation

Characterization of AAV samples


  • Empty/full AAV ratio measurement

  • Serotype-independent analysis

  • Partially filled and overfilled capsid quantification

  • Rough estimation of titer

Rapid analysis requiring little sample

  • < 5 minutes to result

  • Little sample needed

  • Minimal sample preparation

  • Very low operating costs

User friendly operation

  • User training < 1 day

  • Software customized for AAV analysis

  • Benchtop instrument, easy decontamination

Transformative AAV analytics

Mass photometry is a bioanalytical technology that measures the mass of individual AAV particles in solution, quickly and using small amounts of sample.

Mass photometry is ideally suited for measurements of empty/full capsid ratios. Filled AAV capsids have greater mass than empty capsids, so they can be readily distinguished from empty capsids on mass photometry histograms (Fig 1).

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Figure 1 Mass photometry measurement of AAV capsids (AAVDJ serotype) with SamuxMP.  Two distinct peaks are visible: one with lower mass corresponding to empty capsids, and a second with higher mass corresponding to full capsids.

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Figure 2 Mass photometry measurements of empty AAV capsids of different serotypes on the SamuxMP. Mass histograms for four different AAV serotypes, with the mass and standard deviation calculated from three technical replicates.

Serotype-agnostic AAV analytics

The SamuxMP mass photometer can measure AAV capsids of any serotype without the need for protocol adjustments.

Figure 2 shows SamuxMP measurements of empty AAV capsids of four different AAV serotypes.

For each sample, the mass photometry measurements with the SamuxMP revealed a single, symmetric peak at the expected mass, confirming that the SamuxMP produces consistent results across serotypes.

Key advances

SamuxMP software package for GMP

This software solution expands the use of the SamuxMP and the SamuxMP Auto mass photometers to GMP - regulated environments and enables their use within AAV-based gene therapy manufacturing.

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The software package supports compliance with 
the FDA 21 CFR 11 (US) and EU GMP Annex 11​
regulations. It includes three applications: ManageMP, 
AcquireMP and EvaluateMPS. 

The Refeyn service teams also provide installation 
and operational qualifications (IQ/OQ), as well as 
documentation and on-site training. 

To learn more about the SamuxMP and
mass photometry on AAVs, download our product sheet

Frequently asked questions



Can SamuxMP measure partially filled AAV particles?

Yes, the SamuxMP can distinguish empty, partially filled and full AAV particles. 


Can the SamuxMP estimate the virus titer? 

Yes, the SamuxMP has a virus titer estimation function in its analysis software. 


Do I need to calibrate the SamuxMP? How often? 

Yes, we recommend a calibration at least once a day. We recommend performing a 1-point calibration with empty AAV capsids of known mass.  


Is the SamuxMP GMP compliant? 

A software package compliant with FDA and EU GMP Annex 11​ regulations is available for use with the SamuxMP and SamuxMP Auto. In addition, the Refeyn service teams provide installation and operational qualifications (IQ/OQ) for instruments destined to GMP-regulated environments.

Automated AAV analytics with the SamuxMP Auto

The SamuxMP Auto is the automated mass photometer for AAV characterization, autonomously measuring up to 24 samples in approximately 90 minutes. The instrument rapidly measures AAV empty/full ratios, sample purity and particle aggregation for any AAV serotype – with high precision and reproducibility.

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Further resources

Optimizing and monitoring AAV capsid purification using mass photometry.png


Optimizing and monitoring AAV capsid purification using mass photometry

Read this application note and learn how the SamuxMP mass photometer can quantify the empty/full capsid ratio of AAV samples in downstream purification, while also detecting impurities. Discover the advantages of the SamuxMP, in comparison to the gold-standard techniques such as analytical ultracentrifugation (AUC) and cryogenic transmission electron microscopy (cryoTEM), including its low sample and time requirements. 


Quantifying heterogeneous AAV capsid loading using mass photometry

Read this application note and learn how the SamuxMP mass photometer can measure relative abundance of empty, full as well as heterogeneously loaded viral capsids in an AAV sample. Discover how it compares with analytical ultracentrifugation (AUC) in determining the relative abundances of each AAV population. Mass photometry measurements take only minutes, require minimal training and very small sample volumes, which makes the technology optimal for AAV analytics. 

Quantifying heterogeneous AAV capsid loading using mass photometry.png
Further resources

Ready-to-use consumables for SamuxMP and SamuxMP Auto

MassFerence P2_BW_label_gradient backgro

Top up your supply of consumables for analyzing AAV samples with the SamuxMP and SamuxMP Auto mass photometers. Refeyn’s consumables are recommended to ensure consistent measurements.  

Purchase the sample preparation packs which include sample carrier slides and sample cassettes with 6 or 24 wells. Order MassFerence P2, a calibrant tailored for AAV analytics with the Samux mass photometers. Click below to order mass photometry consumables now.

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