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The macro mass photometer

The new KaritroMP is a benchtop instrument that characterizes large viral vectors. Ideal for informing process development in preclinical settings and early drug development, it analyzes samples of adenovirus vectors (AdV) and lentivirus vectors (LVV) in just minutes. The instrument offers essential vector analysis capabilities, including the assessment of sample purity and stability.  

Using novel macro mass photometry technology, this pioneering tool performs single-particle analysis, enabling users to visualize distributions of viral particle populations within their samples. It can resolve distinct populations of vectors and reveal changes over time – indicating whether a sample is suitable for further processing and helping users save time and resources.  

  • Fast, simple, qualitative AdV and LVV analysis  

  • Differentiation of multiple populations, even those of the same size  

  • Evaluation of relative changes across samples, from crude to purified  

Vital insights into viral vector samples

  • Empty/full measurement for AdV 

  • Analysis of purity and stability for AdV and LVV 

Rapid, user-friendly operation

  • 6 minutes per sample 

  • Little sample needed (5 μL at 1E8 – 1E9 particles/mL) 

  • Minimal sample preparation 

  • Benchtop instrument

Essential capabilities​ for process development and optimization

  • Compare production or purification methods  

  • Identify batch-to-batch variations 

Multiparametric analysis

For each particle in a sample, the KaritroMP measures two distinct parameters: Contrast (a qualitative measure related to the particle’s composition and mass) and size. This measurement supports multiple applications, including: 

  • Measurement of AdV empty/full ratios 

  • Assessing the effectiveness of sample purification processes 

  • Measuring degradation in viral vector samples  

  • Comparing production methods 

  • Identifying batch-to-batch variations 

A custom-designed sample carrier will also be available for use with this instrument.

Assessing the effectiveness of sample purification processes 

KaritroMP analysis is ideal for comparing vector purification methods. The instrument can be used, for example, to monitor the effectiveness of purification during LVV production (Fig. 2).

Figure 2. The KaritroMP assesses the effectiveness of LVV sample purification processes. A sample analyzed before and after purification showed a ten-fold increase in the percentage of LVV capsids, corresponding to an increase in the infectious titer. The LVV samples were manufactured by Revvity Gene Delivery (formerly SIRION Biotech). For full details, download the product summary.


Quick measurement of AdV empty/full ratios

Because it measures contrast and mass, the instrument can distinguish populations of particles with the same size but different mass. For example, it can resolve empty vs. full AdV capsids and quantify their proportions (Fig. 1).  


Its speed and excellent contrast resolution make the KaritroMP the only instrument on the market that can quickly measure AdV empty-full ratios. 

KaritroMP size-contrast analysis of an AdV sample revealed 11% of the particles to be empty capsids, while 36% were full.

Figure 1. The KaritroMP measures sample purity, resolving empty vs. full AdV capsids. Full (gate A) and empty (gate B) populations were clearly resolved via KaritroMP analysis of a mixture containing empty, fragmented and full AdV capsids. Particle percentages were determined, as indicated. Samples supplied by The Native Antigen Company Ltd. For full details, download the product summary.  

To learn more about this instrument,

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