Editor's Note
Greetings from Basel! Welcome to the 2nd edition of MxW Bulletin.
It has been an awesome first year for MaxWell Biosystems. We celebrated our anniversary last September and in this issue, we give you a summary of what happened so far.
Our flagship product, MaxOne, has been well received by customers and we look forward to hear about the exciting experiments that they are doing with it. Here, we feature one of our first customers, Dr. Mark Shein-Idelson, who recently published a Nature Methods paper using MaxOne. We also present the new Tissue Holder, a useful accessory for all tissue-related experiments with MaxOne. The Tissue Holder is very important for retinal studies and we recently launched our Retina Application page, highlighting how our customers can use MaxOne for vision research. On the business development side: our Team has grown, we won VentureKick 3, we flew to Boston as part of venture leaders Life Science, and we landed a spot in the Top 100 Swiss Startups.
We are culminating our year-long conference exhibitions around the globe at the largest neuroscience event of the year. On November 11-15, we will be at the Society for Neuroscience Meeting (Neuroscience 2017) in Washington, DC for the first time. We are excited to meet you there at Booth 906!
Enjoy reading!
Marie
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Introducing
Tissue Holder for MaxOne
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Key Specifications
Stable, compact build
Total weight (kg): 1.7
Bottom plate (cm2): 32.4 x 13.4
*Mountable on microscope stages (metric & imperial version available)
3-axis micromanipulator
X travel distance (mm): ±7
Y travel distance (mm): ±7
Z travel distance (mm): ±10
*High precision pressure to flatten tissue sample
*Easy in or out movement on a smooth slider
*Z-position indication using a scale
Replaceable inserts
Material: PMMA
*Includes holes for perfusion tubes
*To use with a fine mesh or membrane
*Glass coverslip for clear liquid-air interface
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Are you doing experiments with retina or acute brain slices? We asked scientists working with tissues what's the most crucial part of their microelectrode array (MEA) experiments. They all agree on one common issue: proper attachment of the tissue on the array is important for reproducible results.
We at MaxWell Biosystems worked hard on the functionality and design of the Tissue Holder to cater to the needs of MaxOne users. The Tissue Holder equips every scientist with a reliable tool to keep the tissue well-attached on the MaxOne MEA sensor area during recordings. Acute tissue experiments are often done with perfusion of carbogen-gassed artificial cerebrospinal fluid (ACSF) or Ringer's solution to keep the tissue viable for several hours. The Tissue Holder allows for simple plugin of a perfusion system and MaxOne's magnetic plate can be used for mounting outlet tubes. It flattens the tissue onto the MaxOne array and maintains the tissue's placement throughout the experiment. The Tissue Holder also allows access to take images of the sample and to project light stimuli for retina or optogenetics studies.
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Meet Us at SfN17
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Want to see MaxOne in action? We will be flying to Washington, DC to attend Neuroscience 2017 (Society for Neuroscience Meeting). Take this opportunity to schedule a meeting with us! We will be at Booth 906 from Nov. 11 to 15. Learn about culturing on MaxOne MEAs, imaging techniques, spike sorting, axon tracking, and electrical stimulation. We also prepared giveaways for you such as pens, magnets, notepads, Swiss chocolates and more!
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Featured: Dr. Mark Shein-Idelson, Max-Planck Institute for Brain Research
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Dr. Mark Shein-Idelson
Max-Planck Institute for Brain Research, Department of Neural Systems & Coding
Frankfurt, Germany
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Hi, Mark. Your past research has focused on neural coding. What are you currently working on?
The human brain is very complex. So our group at the Max Planck Institute for Brain Research focuses on simpler models that we can study in detail. We aim to discover fundamental principles of cortical circuitry and function. We looked back into the evolution of vertebrates and became interested in the sauropsids, a sister group of mammals which includes reptiles and birds. We found that turtles and lizards are excellent models to study the cortex, since their brains have already evolved to exhibit different brain states, similar to mammals and birds during sleep (see Reference 1 for details). Reptiles have a three-layer cortex more similar to the piriform cortex of the hippocampus of mammals. Turtles hibernate during winter, and so, during evolution they developed mechanisms to resist anoxia, making it possible to study the entire brain outside the body. The cells remain stable and excitable such that we can do experiments with the intact brains and eyes attached and keep the preparation functional for multiple days. I am currently studying the visual responses in the cortex. By projecting movies to the eye, I can investigate the corresponding activity across different areas of the brain—all in vitro!
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Interesting! Can you tell us more about your experiments?
I use electrophysiology to record signals from brain cells. Electrophysiology provides accurate information on the activity of single neurons and collective activity of local networks—there is still no other technique that can achieve this at high temporal resolution. My main goal is to measure neuronal activity from the dorsal cortex and medial cortex simultaneously. In mammals, these two areas are equivalent to the visual cortex and hippocampus, respectively. This is why I use MaxOne in my experiments. MaxOne is a microelectrode array (MEA) that enables sampling over a large area, with an electrode pitch at < 20 μm, much tightly spaced as compared to the typical 200 μm in traditional MEAs. High-density facilitates efficient spike sorting. To get as much information from the sample, accessibility and the number of electrodes matter.
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And what have you observed so far?
So far, we saw that the visual response in the cortex of turtles is different compared to what has been reported for mammals. For example, in mammalian cortices, orientation selective cells were found in V1. In turtles, the cells do not respond selectively to the orientation or position of the stimuli. Instead, a lot of different features are encoded in each cell related to motion and all cells are involved in the population dynamics. Regarding information coding, we observed waves from lateral to medial area and there are also oscillations. We are analyzing the spikes and local field potentials (LFP) obtained from the experiments to further decode how the turtle brain responds to visual stimuli.
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You recently published a paper in Nature Methods on large-scale mapping of synaptic projections, also using MaxOne [see Reference 2]. This is a very exciting development for the MEA community.
Yes, the purpose of that work is to push this electrophysiology method forward. Using our ex vivo preparation of the turtle brain and by combining intracellular (whole-cell) and extracellular recording, we were able to show that MEAs can be used to measure not only action potentials, but also synaptic currents close to the postsynaptic cells. We were able to detect axonal projections and the post-synaptic currents of single neurons. These matched the 3D reconstructions of stained cells. In vitro techniques allow us to simultaneously access multiple areas of the brain circuitry long-term, at high spatio-temporal resolution, using different modalities. With in vitro methods we can tackle mechanistic questions, such as, how do different population patterns emerge collectively in brain activity. Using the method presented in the paper, we can now start asking questions on the functional connectivity and integration of activity in large fractions of the cortex simultaneously.
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Finally, could you give us a glimpse to your dream experiment?
Neuroscientists like to be at the edge of technology. If possible, we want to be over the edge. We acknowledge that our view of population activity is limited due to sub-sampling. It would be great if we could get access to the dynamics of every cell in the human brain in vivo—but that is currently not possible. For now, in our current studies, the increase in the number of electrodes enabling to sample neurons simultaneously over a large area is already enough to keep us very busy. Of course, this comes with the challenge to analyze more data. So a pipeline for large datasets that automatically and accurately sorts the spikes and extracts the LFPs would be awesome.
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[1] M. Shein-Idelson, J. M. Ondracek, H.-P. Liaw, S. Reiter, and G. Laurent, “Slow waves, sharp waves, ripples, and REM in sleeping dragons,” Science, vol. 352, no. 6285, pp. 590–595, 2016.
[2] M. Shein-Idelson, L. Pammer, M. Hemberger, and G. Laurent, “Large-scale mapping of cortical synaptic projections with extracellular electrode arrays,” Nat. Methods, vol. 14, no. 9, 2017.
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MxW Report: Application Highlight, Exhibitions, Biz Dev
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MaxOne for Vision Research
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We recognize that vision research is a perfect application of MaxOne. The retina can be flattened on a MaxOne MEA and the retinal ganglion cell (RGC) layer can be directly accessed by the electrodes. MaxOne's high-resolution enables recording of every active RGC in an ex vivo preparation. Combining MaxOne with light stimulation setups allows every scientist to:
- Identify the function of RGCs
- Reveal genetically-defined receptive field mosaics of RGCs
- Characterize the phenotype of transgenic animal retinas
We recently launched our new application page dedicated to retinal studies. We also attended the European Retina Meeting and presented the Tissue Holder for the first time. Check out our brochure dedicated to retina below.
Also, we are very happy to see our VP Scientific Affairs, Dr. Michele Fiscella, and our core MEA technology featured in "The Secrets of Vision" video by SystemsX. Vision disease research is now taking the next leap, with the help of recent breakthroughs in biology and tech. We are excited that MxW is now starting to contribute in this field.
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MxW exhibits around the world
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MxW continues to bring MaxOne closer to scientists internationally. We attended several neuroscience meetings, such as in UK and Japan. We also introduced our products in stem-cell conferences, such as ISSCR and iForum. In all our travels, we communicated with scientists about their requirements in their respective research works and we will reflect these learnings in our current and future products and support system.
In case you missed us in these conferences, you can download our latest brochure below.
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VentureKick, venture leaders, Top 100
 
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2017 is a big year for MxW. Our team has grown from a small group of four co-founders to ten members. We have increased our efforts on the product development side as well as on the sales and marketing aspects.
As a Swiss startup, this year has been very successful. We won the prestigious VentureKick competition in a 'historic final', where three startups won representing the three regions of Switzerland. Around the same time, we got featured in ETH News. Our CEO, Dr. Urs Frey, was chosen as one of the ten representatives of the Swiss National Team who traveled to Boston, USA for the venture leaders Life Science program. And just one year after founding, we landed a spot in the Top 100 Swiss startups. We are very honored to be recognized as one of the best startups in Switzerland and these awards motivate us to reach greater goals for the next years to come.
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Conferences and Exhibitions
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ISSCR 2018
20-23 June 2018 | Melbourne, Australia
MEA Meeting 2018
4-6 July 2018 | Reutlingen, Germany
FENS 2018
7-11 July 2018 | Berlin, Germany
The 41st Annual Meeting of the JNS
26-29 July 2018 | Kobe, Japan
SfN 2018
3-7 November 2018 | San Diego, CA, USA
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