The hows, whats and whys of automated mass photometry



The release of the TwoMPAuto in early 2022 represents an important improvement in the capabilities of Refeyn’s mass photometers. And like with any new product, there are some questions that frequently come up about how it works and what it can do. Today, Gareth Rogers, Director of Product Management, Bioanalytics at Refeyn is here with us to answer some of these questions. Having been closely involved in the development of the TwoMP Auto, Gareth is the right person to tell us how automated mass photometry works, and what makes it an excellent bioanalytical tool.


 

Outline


What is automated mass photometry?

Advantages of mass photometry

Robotics unit functionality

In-plate dilution

Data acquisition and analysis

System capabilities

Consumables

User experience

Future prospects


 


Thanks for talking to us, Gareth! Let’s start from the beginning, what is automated mass photometry?


Happy to be here! When we talk about automated mass photometry, we talk about using robotic devices to streamline sample loading and, in some cases, preparation. Our solution consists of a mass photometer plus a robotics unit. The robotics unit can be retrofitted to our OneMP and TwoMP instruments, meaning that users have the flexibility to add an automation capability whenever they want to or need to. Alternatively, users can acquire the robotics unit as part of a complete, integrated system, called the TwoMP Auto.


A render of the TwoMP Auto automated mass photometer sitting on a benchtop. The front door panel is open to show the liquid-handling robot inside.

The TwoMP Auto mass photometer. The front door panel is open to show the liquid-handling robot inside. The TwoMP mass photometer is located beneath the pipetting area. A separate computer (not shown) operates the entire instrument and stores the data acquired.


What advantages does automated mass photometry offer?


Automation is an excellent way to leverage the speed and reliability of mass photometry. Preparing and adding the samples are the aspects of mass photometry that are most prone to variability. Different people, or the same person on different occasions, can add samples a bit differently. Automation reduces this source of variability, and since mass photometry itself is very reliable, the result is more consistent measurements. Our reproducibility tests show that automated mass photometry has a variability of less than 1% across a measurement series – for both the measured mass and relative proportions of detected species.


Mass photometry is also quick. Once the sample is ready and loaded, the measurement itself takes as little as one minute. This means that if you are doing several measurements, it’s preparing and loading the sample that takes up most of the time. Automation reduces the time between measurements, speeding up experiments a lot.



But do you still need to prepare all the dilutions beforehand?


Not necessarily, actually! Depending on your experiment, it may be possible to automate the dilutions because the TwoMP Auto has an in-plate dilution feature. When it’s used, the liquid-handling robot can dilute the sample by 1/10 or 1/100 before transferring it to the plate and measuring it. This allows you to store the sample at a higher concentration and use the robotics unit to dilute it just before the measurement. Automated dilution can save even more time, and it is especially useful when the samples are dilution-sensitive or when plate adsorption is a concern. Nevertheless, it is important to consider that in-plate dilution is not always the best choice. For example, if your experiment requires the sample to be pre-equilibrated, the automatic dilution may disrupt the equilibrium.



A figure containing data on the reproducibility of the TwoMP Auto. The top half of the figure displays the mass distribution histograms of ten measurements of similar samples of IgG. All ten measurements are shown together in a larger plot, and then individually in ten small plots. The bottom half of the figure contains three bar plots comparing several parameters of the ten measurements. The first shows measured IgG monomer mass, the second the total molecule counts and the third the proportions of monomers and dimers detected.

Automated mass photometry measurements are highly consistent. Autonomously run mass photometry measurements of IgG (10 nM) illustrate the reproducibility of the system. A: The mass distributions (inset: mass histograms for each of 10 wells, shaded light blue) form two peaks – monomers and dimers. The measured mass, calculated from the location of the maximum of the lower-mass peak in each measurement (B), counts associated to lower-mass peak (C) and relative proportions of monomers and dimers (D) are shown across the 10 wells.



How do you run an experiment on the TwoMP Auto?


Like with other mass photometers, using the TwoMPAuto is very straightforward. You just need to load the samples, buffers, calibrants and any other necessary solutions on a 96-well plate and design a protocol. The robotics unit then follows this protocol, pipetting samples in the order and quantities indicated from the solutions on the 96-well plate onto a 14-well sample cassette. Usually, this means that the Auto can measure up to twelve samples in a single run, as we recommend that two of the wells are reserved for calibrants.



A close-up of the liquid-handling robot of the TwoMP Auto highlighting the main components with numbers one to three. Number one, in the center, is a pipette tip box, number two, on the right, is a 96-well plate that holds the samples, number three, on the left, is a multi-sample well cassette. Above these three components there is a robotic pipetting arm.

A close-up of the robotic pipetting arm used in automated mass photometry. The liquid-handling robot uses the pipette tips (1) to transfer sample from the 96-well plate (2) to the multi-sample well cassette (3), in preparation for measurement.



Once the measurements are done, how do you analyze the data?


The TwoMP Auto comes with a full software suite. On the one hand we have AcquireMP, which has a very intuitive interface for controlling protocol design and data acquisition. Once the measurements are done, DiscoverMP makes it easy to analyze them as a batch, quickly and efficiently. It also can be used to create figures from your data and export them.



Since we are talking about data acquisition, what are the mass range and resolution of the TwoMP Auto?


The robotics unit is a module that works with the mass photometer itself to automate the measurements but has no impact on its capabilities. So, the mass measurement specifications for the TwoMP Auto are the same as for the TwoMP. Similarly, if you are working with a retrofitted OneMP, the specs will not change.



Is there any additional equipment needed to work with the TwoMP Auto?


The TwoMP Auto comes ready to use, with all the necessary equipment and software, as well as an anti-vibration system, so for the initial installation, the only thing needed is a suitable space.


You will also need materials for the day-to-day operation of the device. For this, we recommend using the Refeyn lines of accessories and consumables. Specially designed to work with Refeyn’s mass photometers, these make sample preparation convenient and measurement conditions as consistent as possible. I’d especially recommend our sample carrier slides, which are treated to minimize the noise introduced by irregularities in the glass.


You will also need 96-well plates and pipette tips. We have tested a wide range of standard consumables, and we are happy to provide guidance on which to use and where to find them.



How has the user experience been so far?


Our first automated mass photometers are going out into the world and giving good results, which I’m very proud of. We have customers, both in academia and industry, who are putting the TwoMP Auto through its paces, using it to carry out experiments for their different projects. Some of these customers kindly shared with us some of the data that they are collecting with the TwoMP Auto. You can find examples in our brochure on Automated Mass Photometry.



What is in the future for automated mass photometry?


We first developed the automated platform because it was requested by mass photometry users, and we are constantly improving it based on their feedback. In our experience, our customers are always pushing the limits of our instruments and coming up with innovative ways to use them. We will keep integrating new ideas to make our instruments a useful addition to bioanalytic pipelines.



 

Further resources:


Automated mass photometry brochure

Here you can find some details about how automated mass photometry works, as well as case studies that demonstrate how it can be used.


TwoMPAuto product data sheet

This document contains information about how the TwoMP Auto works, as well as its technical specifications and capabilities.


Webinar - Automated Mass Photometry: Easing the Path to Biomolecular Characterisation

In this webinar, Gareth Rogers talks about automated mass photometry and shows data on some of its most attractive applications—such as screening and titration assays.

50 views0 comments