Hi, everyone. Thanks for joining our webinar today. My name is Jaden. I am a sales engineer, and I’m part of the ABER team located in the US office. I’m joined today by my colleague Claire. If you want to go ahead and introduce yourself. Thanks, Jaden, and hi, everyone. I’m Claire Thomas, the product application and lab specialist at ABER based in the UK. I’ll be presenting alongside Jaden today, and I look forward to hearing all your questions. Today, we’re going to be talking about the basics of capacitance technology and how real time cell biomass monitoring could be valuable in your bioprocess applications. We’ll have a section for q and a at the end. So if you do have any questions that come up, please feel free to send those in the chat, and we’ll address them at the end of the presentation. Offline measurements and manual counting methods are historically the gold standard for monitoring biomass and cell growth. But offline measurement methods can present a number of challenges. Some of these might be the time and effort that goes into taking cell counts, especially if you’re using a manual cell counter. Insufficient sample points, so not getting a full picture of your cell data and behavior over the course of the run. There can be a risk of contamination if you have to open the bioreactor to take samples. There might also be risk of error, and that can come from a variety of sources, maybe during your sample preparation procedure. Some counters might have inherent variability, or if you have different people taking counts slightly differently. So overall this leads to just not having a complete knowledge of your critical process parameter, that being the biomass. Using ABER capacitance, which is a real time and in line technology, can have a number of benefits. So firstly, the measurements of real time measurements, so you’re getting data on the cells and the process almost immediately. You can use that data to monitor the bioprocess at the most basic level, but then you can also control parameters like feed rate later on to get a level of automation. You can use capacitance on a variety of different platforms, platforms, and it’s also scalable. And then there’s no need to take samples, so that mitigates some of the time cost and risk for error and contamination that I mentioned previously. And you’ll be getting accurate and consistent measurements. So overall, you just have a more complete knowledge of your critical process parameter and biomass. And now Claire will be talking about the theory behind the technology. Thanks, Jaden. In this section, as Jaden mentioned, I’ll be covering the theory of the measurement and how ABER effectively measures the biomass in your bioprocess. Let’s get started. The ABER technology measures two basic parameters, capacitance and conductivity. In simple terms, capacitance is the ability of any substance to hold charge around itself measured in picofaras per centimeter, whereas conductivity is the ability of any substance to give away charge. This is measured in millisiemens per centimeter. In order to understand the principle of the technology, we need to return to the basic structure of the cell membrane. The cell membrane is impermeable with respect to charge, specifically live cells, meaning that there is no free flow of ions across the membrane when under the influence of an electric field. This is a key characteristic of the cell that allows us to measure the viable biomass. Here, there is a simple animation to best illustrate how the capacitance measurement works. When an electric field is applied across the suspension, the ions move to their respective electrodes. So the positive ions move to the negative terminal and vice versa. As soon as they reach the cell membrane, there is a polarization effect of the live cell membrane resulting in a buildup of charge. This is what acts acts as that, like, tiny, weeny capacitor. The greater the number of live cells, the greater the capacitance measured. As we are measuring the built of charge around the cell, note, this is not just a reflection of cell density, but also a reflection of cell size. Therefore, capacitance is actually, directly proportional to membrane bound by a volume of the suspension. So, basically, put capacitance is everything biological in the suspension, whereas conductivity can correlate with everything chemical. In contrast to this, as cells begin to die, they can’t hold charge around themselves anymore, and the membranes are not intact, so they’re leaky with respect to charge. So it doesn’t mean they have literal holes in them. It just means they allow the free flow of ions across the membrane. This means dead cells no longer have the ability to hold charge around themselves and are basically invisible to the technology. Likewise, solid media particles and gas bubbles can’t be measured by the technology as they can’t hold charge around themselves. They do not have that bilayer to have that build of a charge under the influence of an electric field. Now we’ve covered the theory behind the measurement. How is the ABER technology actually measuring the capacitance? As you’ll see on the right, we have an annular probe, which would typically be installed into your bioreactor. It has a stainless steel body and a FORTRON tip. There are four platinum electrodes embedded in that FORTRON tip, and the ABBA system is simultaneously creating and monitoring the electric field. So the outer to create the field and the inner measure the resulting voltage. The electric field generated is an alternating current in the radio frequency spectrum, typically between fifty kilohertz and twenty megahertz. Though typically, a single measurement frequency is selected, and the resulting capacitance at that frequency is monitored to give a growth profile over time. So this is the most common use of the technology. Finally, I’ll discuss some organisms that could be measured by the technology. These give you some examples of cell types that can be measured by capacitance, but this list isn’t exhaustive. The main criteria for capacitance measurement is an intact cell membrane, which all of these cell types have in common. If you have any questions regarding, whether your cell type would work with the other technology, we’d be more than happy to answer those. At this point, I’ll now hand over to Jaden to cover some example platforms of the technology. As we mentioned previously, ABER capacitance technology can be used on a variety of different platforms. So here we have a BioBlue vessel from Eppendorf used with our annular probe. These are our reusable probes that can be installed in benchtop bioreactors. They come in different lengths to accommodate different vessel sizes. Here we have an RM bag with the patch style capacitance probe installed. The patch probe is a single use version of our technology sold by Sartorius as the BioPat biomass. Here’s an example of our flush version of the probe being used in a pilot scale lab. So these flush probes can be installed in standard side entry ports on larger bioreactors. This is another example of the Biopat biomass patch silo probe being used on a much larger single use fermenter. Finally, this is an image of the, ABER Futura Neo probe. This is a single use probe specifically designed for Thermo Fisher single use bags. AVR probes are used in many more platforms than these. If you have questions about suitability for your process, we’re always happy to evaluate that with you if you share information with us on your process and application. Now Claire will go through some examples of ABER capacitance data. Overall, in terms of applications, the most basic use of the ABER technology is to monitor your cell concentration in real time, which then gives you a detailed fingerprint of your process. The fingerprint can be used for troubleshooting purposes when the growth profile or the culture or fermentation deviates from that batch fingerprint or golden run. To demonstrate this, I have a typical growth profile for a fed backed culture. So these were NS zero cells that were fed at regular intervals with media. So to explain the graph, in the dark blue trend, we have raw capacitance in peak hours per centimeter. The light blue trend is capacitance, which has been correlated with offline, cell counts in cells per milliliter, by applying a simple calibration factor. Finally, we have the pink squares, which represent the offline viable cell density measured using a seed test counter. So, typically, customers would only get the pink squares. So you can see how much more detail, the ABER technology is providing. It’s kind of filling in those gaps. You’ll also notice there are characteristic drops in capacitance, which indicate feed additions. This is an artificial decrease in capacitance caused by dilution effect of addition of media. The graph illustrates the benefits of using online real time technology such as capacitance relative to an offline method. It demonstrates the values that can be gained by building a complete detailed profile of your culture. Additionally, information can be attained on the real time capacitance measurement. So what we can see is midway through the process, we observe that the capacitance decreases prior to feed additions, which indicates that the cells have started to die. The user here was able to identify the optimum time for feed additions to prolong their culture, based purely on the continuous capacitance measurement. The con the customer would have been unable to do this, using the offline counts as they would have given ins insufficient data points. So this really shows the benefit of continuous monitoring. As mentioned by Jaden, we are used in a variety of platforms and scales right away from r and d through to manufacturing. Therefore, successful scale up between these platforms is an important aspect to ensure the capacitance can scale with the process. So Sartorius, investigate the scale of their process with capacitance at the various platforms, you’ll see here. So we’ve got from a RM fifty liter right the way up to a one thousand liter, stir tank reactor. The data illustrates that ABER was able to successfully scale up with their process. This not only means the capacitance, can be measured across different platforms. It also shows that capacitance can be used, as a real time key performance indicator to determine whether the scale up strategy has been successful. As a side note, you’ll notice there’s a process deviation in one of their runs, which is the stirred tank reactor thousand liter. And what the user was able to do was to quickly rectify this because they noted the deviation in real time. So this shows another benefit of continuous monitoring of the process as the user was able to rectify the mistake in order to save that run. I’ll now hand over to Jaden to finish this off with our diverse application tree. Following on from the data that Claire presented, Capacitance Technology has a very diverse application tree. We mentioned the most basic application, which is monitoring your process. Here, you can create a batch fingerprint to compare future runs to. You can use this to detect, process deviations or critical points. You can extend this to automatic control of your process. Capacitance technology also works with processes that are normally difficult for manual counting methods. So this can include things like micro carriers. Another example would be filamentous fungi. And then related to automatic control is using the capacitance profile to identify critical points like harvest times or to control the perfusion rate and perfusion runs. Thanks everyone for your attention. Hopefully, this was a comprehensive introduction to capacitance technology and some of the benefits you can expect to see when adding it to your PAT portfolio. We’ll have a q and a session beginning shortly, but please feel free to reach out to us anytime using the support email address shown on the screen. Thank you for listening. A q and a session will begin shortly.
