New Matter: Inside the Minds of SLAS Scientists

Lab of the Future | Mass Spectrometry Methods in High-Throughput Screening with Maaike Bras

January 30, 2023 SLAS Episode 140
New Matter: Inside the Minds of SLAS Scientists
Lab of the Future | Mass Spectrometry Methods in High-Throughput Screening with Maaike Bras
Show Notes Transcript

In continuing our Lab of the Future series, we're joined by Maaike Bras, scientist assay development (Pivot Park Screening Centre), for a detailed discussion on the applications of mass spectrometry methods in high-throughput screening.

For a transcript of this episode, please visit this episode's page on Buzzsprout.

Key Learning Points: 

  • How mass spectrometry can be used for high-throughput screening
  • How deep learning and other data mining/analysis methods are improving mass spectrometry 
  • What mass spectrometry advancements are being made to enhance the lab of the future 
  • Mass spectrometry advantages for affinity-based assays compared to other assays methods

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Hannah Rosen: Hello everyone and welcome to New Matter, the SLAS podcast where we interview life science luminaries. Today we'll be continuing our series focusing on the lab of the future. Joining us today is Maaike Bras, an Assay Development Scientist at Pivot Park Screening Center, who is here to discuss with us the application of mass spectrometry and high throughput screening. Welcome to the podcast Maaike!

Maaike Bras: Hi Hannah, thanks for having me.

Hannah Rosen: It's our pleasure, so to start off with Maaike, could you just kind of provide us with a little bit of your professional background?

Maaike Bras: Yeah, so I am... I have been working in the pharmaceutical industry about over 15 years now. I started my career at a Dutch pharmaceutical company called Organon at the department specialized in assay development in HTS, and it's also my first acquaintance with the lab automation. And ten years ago I joined the Pivot Park Screening Center as an assay development scientist, and at PPSC we provide drug discovery services in... in all the fields of assay development, lab automation, and high throughput screening, and lead profiling. And this is also where I first got acquainted with mass spectrometry and the automation of that. Since we acquired like three years ago, the rapifleX from Bruker, and in combination with Spotter Instruments we are now able to run fully automated MS assays. So, the last couple of years I had the privilege to work, you know, with the... with this equipment and in several MS projects from well screening to ASMS assay development.

Hannah Rosen: That's great, so you're actually relatively new to using mass spectrometry.

Maaike Bras: Yes, yeah.

Hannah Rosen: Was it a little intimidating at first? I don't know, I personally am very intimidated by mass spectrometry.

Maaike Bras: No, I agree. I found it really overwhelming the first steps, and all the information that's coming your way, and there's so many possibilities and things to do that, yeah. No yeah, yeah.

Hannah Rosen: So, can you just give us a maybe a little bit of information then on, you know, how can mass spectrometry be used for high throughput screening?

Maaike Bras: Yeah, so I think the key in this is automation and right equipment. So, to increase the amount of samples you're able to process within one day, to be able to process high number of samples in a relatively short time, and also measure them with good resolution and sensitivity is really key to making this high throughput and making it available for screening. For example, for now in our HCS system we are now able to run like, up to eighty 5036 well plates per day, so that's like 120,000 data points. So, these are really advancements that going really rapidly in the field at this moment.

Hannah Rosen: Well, so were you, before you guys got all of this mass spectrometry equipment, were you running like, similar assays but using different methods?

Maaike Bras: Yeah, so we mainly specialized in biochemical assays using fluorescent... fluorescent labels, specific detection reagents, cellular assays with also fluorescent or luminescent readouts. Just, uh, standard, uh, assays, yes.

Hannah Rosen: Well, how... would you say then, you... you focus a lot, I understand, on affinity-based assays, that's correct?

Maaike Bras: No yeah, mostly screening, and affinity-based assay is something that we have been setting up in our lab in the last couple of months, so that's also relatively new. Our main focus is primarily the... the... the screening part, yeah?

Hannah Rosen: Are you guys moving over into the affinity-based assays because of this introduction of mass spectrometry to your labs?

Maaike Bras: Yeah, and it's just... just also a demand from the field that this is something that is emerging and there's interest to replace other target binding assays, so that's why we started introducing the ASMS in our lab.

Hannah Rosen: So, how can the mass spectrometry be used for these affinity-based assays?

Maaike Bras: Yeah, ASMS, of course, makes use of the binding interaction between your ligand and your target of interest, and your ability to isolate your target binding compounds from the mixtures of the small molecules in your target, and then using MS with high selectivity sensitivity to measure those molecules. And there are different methods described, mostly differ in the way how you isolate your ligand and target complexes from your non-binding compounds. And the one that we implemented in our lab uses a SEC resin, so size exclusion step, to... to isolate your ligand bound to your target and then measure them using our method of MS. And we are now able to do that with approximately 5000 compound per day, so that's relatively high throughput. And we're looking into the possibility also to start upscaling that by pooling compounds to test more compounds per well, generate more data.

Hannah Rosen: So, you can test multiple compounds per well?

Maaike Bras: That's the next step in this process. So, we are... have now set up the assay in our lab. There have been some... some minor steps made, but this is the next step to really, uh, scale up the assay and also really make the ASMS applicable for real high throughput screening, so really processing like hundreds of thousands of compounds in a acceptable time.

Hannah Rosen: What advantages does mass spectrometry have for affinity-based assays compared to other affinity-based assay methods?

Maaike Bras: Yes, so of course there's the label free advantages, so there are no radio labels, no fluorophores or chromophores. It also does not really require specific knowledge of your target, or development of target specific assay conditions. Just minor buffer adjustment might be enough to... to screen a completely different target. There's also no heating or unfolding of your protein involved, so you can really measure it intact. And above all is that we are now able to run it in a high throughput setting. So that's, I think, the main advantage compared to the normal SPR or TSA methods that are relatively low throughput and, um... yeah.

Hannah Rosen: Is this similar to the advantages that you see using mass spec compared to the other screening methods that you have been using previously?

Maaike Bras: Yeah, I think that's... that's similar, so the main advantage, of course with mass spectrometry is that you can measure molecules without labels or the texture reagent that can interfere with your molecule of interest.

Hannah Rosen: So, you have about the same high level of throughput, would you say, compared to other methods, using mass spec?

Maaike Bras: It's... it's a little bit slower than... than with the biochemical assay because the processing times of your sample are a bit lower. But if you have a look at the data that you're getting out of it, you will need less follow up on your compounds of interest, so it takes a little bit more time to screen your full library, especially for the biochemical assays. With the ASMS we're now looking into compound pooling, so this might really significantly increase your throughput. But for the standard, uh, high throughput screening, it's a little bit slower, but the data that is coming out of it should result in better hits, less follow up assays needed.

Hannah Rosen: That's nice, are there any advancements that are currently being made in mass spectrometry that will make the technique more compatible with high throughput and automated processes in the lab in the future?

Maaike Bras: Yeah, so developments are moving really fast in the... in the last couple of years, so there are, of course, a lot of automation equipment that is on the market, but there's also now developments in acoustic injection, so Echo MS, where samples are transferred into the mass spectrometer using a droplet injection. There's also a lot of development in the LCMS field, where faster sample handling is really... have taken a flight in the last couple of years. And also, uh, better, uh, resolution, separation of molecules, for example, dim stuff, equipment from progress, really setting to gain higher sensitivity and able to detect molecules at a lower concentration. So, there are different angles that are all working on getting better data, faster data processing, more samples. Yeah, and of course next to that there's a software development. So, also analyzing data. There's also steps to be made there, I think.

Hannah Rosen: Yeah, are there being more moves made to kind of integrate mass spec equipment into the general workflow of the labs? You know, like we've kind of seen liquid handlers are really being integrated into the lab space more, are you seeing that happening with mass spectrometry equipment?

Maaike Bras: There are more and more articles also popping up with mass spec used in high throughput screening, so there's definitely something that is evolving.

Hannah Rosen: Yeah, how are deep learning and other data mining and analysis methods improving our ability to use mass spectrometry?

Maaike Bras: Yeah, so I'm not really into... into the deep mining, but I can imagine that... that the more these techniques are used and the more knowledge there becomes available that also the development of certain algorithms to process your data more easily, or with less knowledge of beforehand on the molecules that you are looking at that, it will of course take a flight, yeah?

Hannah Rosen: Do you think that as mass spectrometry technologies improve, it's gonna start replacing other high throughput assay methods in the lab? I mean, obviously it's already starting to happen for you guys, do you see this becoming a more widespread trend?

Maaike Bras: Yeah, I think it's... this is really what you see, and also the demand that we are getting from our customers is really for, what can you do with the MS based assays? What are you able to process? Yes, it just has to become a little bit more known broader, I think. So, a lot is already possible with all the advancements that are being made at the moment, and it will only become more applicable for automation and HTS. I don't think it will replace everything, since there will always be, uh, molecules that you just can measure or unstable... unstable in the... in the whole process. But it's definitely something that I think is, yeah, is starting to at least be integrated in more places and is here to stay, I think, yeah, yeah.

Hannah Rosen: So, in your experiences in the lab, you know, now that you've kind of transitioned into using a lot of these mass spec technologies, are there any instances where you kind of have to go back to the previous assays or screening methods you were using before mass spec, or has mass spec kind of replaced everything in your lab space?

Maaike Bras: No, it's definitely not a replace everything. There's still some assays that we just not able to get to work, so there's still also from the customer's point, there are still a... a lot of questions just for normal biochemical assays, so it definitely hasn't replaced everything. But we are getting more and more request for mass spectrometry, and especially the ASMS is really getting interest now that we are also going out with this.

Hannah Rosen: It's interesting, do you ever... have any customers that come to you and say that they don't want mass spectrometry to be used?

Maaike Bras: No, but it's not something that gets discussed with every customer. So our customer, most of the time, has their own idea or already... already an assay that's running so MS is mostly something that is popping up when a assay has to be developed from scratch, or it... as an orthogonal assay, for example, yeah.

Hannah Rosen: Yeah, so there hasn't been a lot of resistance in moving over to the mass spec, do you think?

Maaike Bras: No, no, not the resistance, but I think, as I already said, it needs to get more known. And there's also, we have now implemented the, I think, one of the first CROs with a... with a large mass spec capability, and also at the customer side if there's not a primary assay developed with a mass spec it's, most of the time, not something that they come to us with for a primary screening. It is something that we offer, and there is more and more request for that.

Hannah Rosen: That's interesting, so do you think that as people develop more techniques for using this technology, it's going to become requested more often and... and increase in popularity?

Maaike Bras: Yeah, I think that's... that's just the point where we are now, that it is to become more broader, knowledgeable. And also, for that people have to be able to set it up at their own labs to really transfer it to a business as ours, I think.

Hannah Rosen: What are the barriers that are... might be preventing some people from setting this up in their own lab spaces?

Maaike Bras: I think the investment for mass spectrometers is still relatively high. It's not something that you can buy for... for a couple thousand of Euros and... or dollars, and it still need specific knowledge of how to set up your assays. We are also still learning and, yeah. I think a good basis to... to have people to where you can gain knowledge. So, we have also several collaborations with other parties where we try to increase our knowledge on what we can do with the equipment, and also what are new fields to explore.

Hannah Rosen: Do you see, in the future, this becoming a more, you know, accessible technique or piece of equipment? Do you see the cost coming down? Do you see more people getting trained on it, or do you think that it's still for a while yet going to be a little bit more specialized?

Maaike Bras: Yeah, yeah. I think the... the... the developments that are currently going on are making the equipment easier to use, as it would make it easier to use. And that's also making more people having access to it, but I think it's... I'm not sure how it, costs wise, for the equipment that is now getting to market, how it's relating to that.

Hannah Rosen: What are some assays that we can do with mass spec now that we wouldn't have necessarily been able to do 5 or 10 years ago?

Maaike Bras: Yeah, I think it comes back to the same, well, to the same automation of the MS has really taken flight the last couple of years, so now being able to do standard biochemical assays in 1536 well is really something that we wouldn't be able to do a couple of years ago, and there's been such a significant improvement in sample processing, sensitivity, resolution. And also the... the development that makes sample clean up unnecessary. So just with minor buffer adjustments you can make it MS compatible to something that's really making a difference with a couple of years ago, I think.

Hannah Rosen: Was there anything, you know, when you first started using mass spec a couple of years ago, were you surprised by anything? Was there anything in there that you didn't think mass spec could do, or that you had learned about mass spec previously that has since changed?

Maaike Bras: I think there are so many possibilities, and... and starting, uh, we started just with the simple biochemical assays, how to set that up, and I think that's something that is relatively simple to grasp, not really new. But now, the last couple of years we gaining more fields and also the ASMS which is something really that I thought, OK, we're now able to use it for binding assays. We're also exploring the possibility look at cellular assays. There are really things that are now, yeah, once you get to work with the equipment and get more... more known with the whole principle of mass spectrometry and you start reading about it, you get surprised, and I think almost anything is possible. What we would normally run on a... on a HTS system is now possible to, in some extent progress to mass spec.

Hannah Rosen: Wow. Are there any assays, or types of assays, that we can't currently do with mass spec that you think we will be able to use mass spectrometry for in the next 5 or 10 years?

Maaike Bras: I don't know if there's anything that we really can do at the moment, but I think there are significant improvements made for cellular target-based assays. So, to really perform cellular screens with the mass spec, and also in LCMS, there are major improvements made already in the last couple of years, but are still growing to really improve the sample throughput, so I think it's mainly targeted at sample throughput, different MS technologies making improvements in the cellular assays.

Hannah Rosen: For any individuals out there who are working in assay development and high throughput screening but may not have much familiarity with mass spectrometry, do you think it's important for researchers to start familiarizing themselves with these techniques now so that they don't get left behind as mass spectrometry is improve and become more common?

Maaike Bras: With all the developments that currently are going on in the field, the applications for MS in the... in high throughput screening will only grow when taken into account the advantages that are related to MS. So, with the label free and the other at which I already mentioned, it's probably be something that will be represented in the screening lab in the future, definitely in... in any way or form it will definitely be incorporated.

Hannah Rosen: Do you see this is something that is going to be more common for younger generations of scientists to be trained on it, whereas maybe it wasn't as common in the past?

Maaike Bras: Yes, I think... definitely think so. So, especially in the lab of... in the field of the assay development and high throughput screening it... there will be more people trained and it will be something that you will have to gain some knowledge about if you want to participate in the field, I think.

Hannah Rosen: Well, you know we're almost running to the end of our time, but I just wanted to ask Maaike, before we close out is there anything that we didn't get a chance to talk about with mass spec and its role in the lab of the future that you would like to add to this discussion?

Maaike Bras: I can't... I can't think of anything right now. I think the we covered the most of the... of the things I think I'm really, I'm just excited that we can... we were able to share this with you and we are really excited about the technique in our lab and the things, uh, the... the things that we can do with it and the new fields that we are exploring with ASMS and the cellular assays that, uh, yeah, it's just something that, uh, people have to keep an eye out for.

Hannah Rosen: Definitely. Well Maaike, thank you so much for joining us today. It's been a real pleasure talking to you and learning more about the new uses for mass spectrometry, and we really hope to see you and others at the pivot Park Screening Center at some of our future SLAS events.


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