Q&A with mass photometry users from a global biopharmaceutical company
Dr. Martin E. and Dr. Marie A. are experienced scientists – characterizing antibody and gene therapy samples at one of the top 5 pharmaceutical companies. Their lab recently acquired a TwoMP Auto mass photometer and they spoke to us about their initial experience with the instrument and how they are using mass photometry to overcome their analytical challenges.
The interview responses have been edited for length and clarity.
Outline
First impressions: Mass photometry, TwoMP Auto installation and training
Q. When did you first hear about mass photometry?
Martin: I first heard about it [mass photometry] on a talk when I was doing my Ph.D. It was a new technique back then and the Refeyn founders were invited to give a talk. I brought that knowledge about mass photometry from academia to biopharma. At some point, we had a question of what analytical technology to use for protein mass measurements and aggregation; should we use SEC-MALS or DLS? I remembered mass photometry and we decided to test it.
Marie: I also heard about mass photometry while I was doing my Ph.D. I came across the Young et al. 2018 Science paper that described mass photometry and I thought it was a cool technique.
Q. You had a TwoMP Auto installed 3 months ago. Can you describe the process so far, in terms of installation and support from Refeyn?
Marie: The process so far has been very good. Colin Grant [Senior Support Scientist - Applications at Refeyn] did the installation. We measured the first few samples and that went quite well. Then we had a challenge with the liquid handling system and shortly after Colin came around and resolved it. At that point, he gave us more detailed training on how to get the best out of the automated mass photometer. That was really good because he answered all the questions we had. Also, we found that both the AcquireMP and the DiscoverMP software are quite easy to handle and the figure feature in DiscoverMP [with which you can plot mass histograms of one or multiple measurement files] is very cool.
Q. How has the mass photometer been received by your colleagues?
Marie: There is definitely a demand for mass photometry because it is a very fast technique to analyze samples and get information about the mass of - for instance - proteins in a sample. It works for lower concentrations, which is preferable for certain samples. People are really interested in the technique.
Martin: I think that it is very cool that you can teach someone how to use the mass photometer in one day. There are several people [in our company] who want to take measurements because they are really curious, and this can be easily arranged since they don’t need to undergo elaborate training to use the mass photometer.
Q. Are you happy with the mass photometry results so far?
Marie: So far yes.
Martin: So far, from the stuff we measured, we are quite happy. We are still trying to figure out what is the best sensitivity we can achieve since we are very limited in sample volume and concentration in some projects. We have been very surprised with how low you can go in terms of absolute sample concentration because with some projects the volume is not actually the bottleneck, but the concentration is.
Overcoming experimental bottlenecks with mass photometry
Q. Has mass photometry helped you overcome any key bottlenecks in your analytical workflow?
Martin: The biopharma organization I work at is predominantly making therapeutic antibodies: Antibody-drug conjugates (ADCs) and bispecific. We were thinking for about a year to get a mass photometer to study protein aggregation, because, with mass spectrometry, it is not easy to distinguish the high-order molecular weights. With light scattering techniques, like DLS, you need a large sample volume, but we have a limited sample amount, so I was a bit hesitant to use those techniques.
Also, now we have some gene therapy products and that was part of the motivation for buying the mass photometer. The mass photometer can do both, antibody analytics and measure new modalities as well. This idea was very well received, and we got the funding quite fast.
Q. In a typical day, what are you using mass photometry for?
Martin: When samples arrive at our lab for characterization, we know that they contain antibodies and that they should be stable. However, there is often self-association or protein degradation occurring in samples, and to measure those things mass photometry is quite useful. For the gene therapy products, we want to use mass photometry to measure empty/full AAV capsid ratios, but we are also thinking of other ways to use it.
Impact of mass photometry and time considerations
Q. What role do you see mass photometry playing in your lab?
Martin: In the future, mass photometry will become complementary to other bioanalytical methods for protein characterization. For example, SEC-MALS or SEC data don’t give you much information about high or low molecular weight peaks. Elucidating what these peaks are with conventional techniques can be burdensome, but with mass photometry, you can do a one-minute measurement and see if you have a dimer or a trimer.
Mass photometry fits perfectly into our analytical workflows when we know there are additional species in our samples [such as aggregates] but we don’t know their mass or their oligomeric state. Now we finally have a suitable technology to fill that gap. We are also considering using the TwoMP Auto mass photometer to measure nucleic acids – DNA and RNA. Since gene therapy is really picking up, trying to measure all the nucleic acids involved would be very cool for us.
Q. One of the benefits of mass photometry is that it is quick. Have you found it has reduced the time you need to address an analytical challenge?
Martin: If you just need to know the oligomeric state, the empty/full ratio of AAV preparations, or the mass of biomolecular species in your samples, the turnaround time for size-exclusion chromatography is a day, whereas, with the mass photometer, it is half a day; this includes time for sample preparation, measurement, and figure generation. To assess the empty-full AAV capsid ratio, you could do ultracentrifugation, but this is a week of work. If you do cryo-EM, the turnaround time is a month. With mass photometry, you get results on individual samples within minutes, and you need way less material.
Many thanks to Marie and Martin for sharing their experience with mass photometry! To learn more about how mass photometry and automated mass photometry work, check out the resources below.
Further resources
Here you can learn about the basics of mass photometry and the main advantages it offers for the analysis of biomolecules.
This document contains information about how the TwoMP Auto works, as well as its technical specifications and capabilities.
In this webinar, Gareth Rogers, Director of Product Management, Bioanalytics at Refeyn discusses in detail automated mass photometry and shows data on some of its most attractive applications—such as screening and titration assays. He illustrates how automation and the associated improvement in reproducibility can streamline biomolecular characterization.