DR. Madeline J. Dukes, an Application Scientist from Protochips talks to AZoNano about their range of products, that are pushing the boundaries for laboratories who in the past where challenged when it came to in situ TEM tools.
MR: Please can you give a brief overview of Protochips and the work you do?
MD: Protochips was founded in 2002 to bring in situ TEM tools from notoriously challenging laboratory curiosities to robust, easy-to-use tools widly accepted by mainstream researchers. We currently offer three products for in situ TEM research: Fusion, Atmosphere and Poseidon Select.
All three have pushed the boundaries of what’s possible to image in the TEM, being featured in over 500 peer reviewed publications from researchers around the world. Our goal is to develop
in situ TEM solutions that enhance existing research tools, enable innovative new discoveries, and improve scientific understanding.
MR: Can you briefly describe Poseidon Select and how it works?
MD: At its core, Poseidon Select is pretty simple. By creating a sealed enclosure within the TEM using electron transparent silicon nitride membranes, liquid can be introduced into the TEM.
Many material and biological processes occur in liquid, researchers use Poseidon Select to image previously unforeseen samples and processes at spatial resolutions only accessible in TEM.
MR: What results will you see using the Liquid heating package and the Poseidon?
MD: Part of the exciting thing about Poseidon Select with liquid heating is that it opens up a world of opportunities for new research applications. We’ve seen our customers investigate nanoparticle nucleation and growth, study metallic corrosion, and even cook eggs – all within the TEM. So to answer your question, I don’t know what you will see, but that’s the exciting part!
MR: What are the major advantages and features of the Poseidon and the liquid heating package?
MD: The reality is that most material and biological processes occur in environments far different from the high vacuum conditions of the TEM. Our liquid heating package exploits the robust, OEM approved Poseidon Select holder to better allow researchers to study samples in, realistic environments [MD1] at relevant elevated temperatures.
It features our proprietary MEMS based E-chips, where thin platinum coils heat the surrounding liquid to temperatures up to 100C. It does all of this without compromising EDS capabilities and the ease of use our customers expect.
MR: In what way is the Poseidon heating package unique ?
MD: The Poseidon Select heating package delivers rapid and precise temperature control of the liquid contained in the sample chamber with <4% accuracy.
The real genious in the system is the design of heating element on the chips themselves. Because the heater surrounds the liquid, we can ensure that the liquid is heated uniformly across the viewing window.
MR: What is the highest temperature the Poseidon can reach?
MD: Water boils at 100C which is the maximum temperature at which we rate our heating chips. We find that most of our customers are imaging samples in hydrated environments, so this temperature range is more than enough for their research needs.
MR: How do you measure the temperature and results of the Poseidon Select?
MD: Measuring temperatures of such small quantities of liquid is really challenging to get right and really easy to do wrong. After months of research, we found that by implementing a closed-loop control process with our Clarity process, we were able to maintain consistent temperatures, as the software is constantly checking temperature and making adjustments to maintain the temperature desired.
MR: How does the heating capability affect the chemical compatibility?
MD: Chemical compatibility is always something to consider when high temperatures are involved. That’s why our engineers designed all of the sealing elements and tubing out of inert materials like Viton and Titanium that are proven to stand up to the most corrosive environments.
However, certain chemicals can and do become more reactive at elevated temperatures. In those instances, we have indicated the maximum safe temperature that those chemicals may be used our in our chemical compatibility guide.
MR: How important is safety within the Poseidon select?
MD: Is safety important? Yes. Do our customers need to worry about safety? No, provided that they follow the procedures and recommendations that we have developed for Poseidon Select.
We worked hand in hand with the major microscope manufacturers to make sure Poseidon Select met their rigorous standards for safety, compatibility, and reliability. It’s why we’re the only liquid cell holder approved for use in these microscopes, making us the safest system in existence.
MR: Why is the tungsten heating coil of the Poseidon Select patterned on silicon rather than on a viewing window? What is the difference?
MD: This approach yields the most accurate, uniform heating of the liquid. Think of it this way, if you wanted to heat some water in a mug, would you dunk a red hot coil in the water until everything boiled?
Or would you just heat up the cup itself? Putting the heating coil on the silicon instead of the window is like heating water in the cup, as the entire volume of liquid is heated uniformly.
MR: Can you tell our readers about any case studies?
MD: One area we’ve seen a lot of interest is in research surrounding nanoparticle nucleation and growth phenomenon. We recently hosted a webinar ( http://www.materialstoday.com/materials-chemistry/webinars/in-situ-tem-the-new-frontier-for-liquid-chemistry/) featuring Saso Sturm, a researcher using Poseidon Select to study these phenomenon.
Dr. Sturm and his colleagues were able to fine tune the heating system to nucleate up-converted nanoparticles with different properties based on the heating scheme. I won’t spoil the ending, but the webinar is really worth the watch.
MR: Where can our readers go to find out more?
MD: Our website is a great place to start: http://protochips.com/products/poseidon/. We’ve got dozens of application notes on topics ranging from carbon nanotubes and liposomes to lithium ion batteries and nanoparticle nucleation. And of course, we’re always excited to answer any questions your readers may have, so we’d love to get in touch! About Dr. Madeline J. Dukes
Dr. Madeline J. Dukes joined protochips as an Application Scientist in 2011, where she works directly with customers and collaborators to develop new applications for in situ electron microscopy. Prior to Protochips, she was a Ph.D student at Vanderbilt University, where her research centered on using electron microscopy techniques to image and map the three dimensional distribution of nanoparticle tagged proteins on intact eukaryotic cells with nanometer resolution.
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