Hello Nanotech Enthusiasts,
In an effort to showcase interesting nanoscience research, we're kick starting a Q&A blog this year. We've got a great first guest. Andres Canales is a Senior Laboratory Engineer at Advanced Silicon Group (ASG). ASG is developing the next generation biosensors.
Andres, tell us a little about yourself and your background.
I just reached two years of being the Senior Laboratory Engineer at ASG. Before that I was working as a researcher in the Bioelectronics Group at MIT, where I spent 9 years. I got my Master's degree and PhD in Materials Science and Engineering, and then worked as a postdoctoral fellow during that time. Before coming to MIT, I got my Bachelor's degree in Chemistry at the Universidad Nacional Autónoma de México in my native Mexico City.
How did you get interested in nanoscience/engineering?
As you can tell, I have been interested in science/engineering for a long time now. Even before entering college, I knew that I wanted to get into science or engineering. During college, I took classes on many subjects of chemistry, but the ones that interested me the most were those relating to materials science. This branch focuses on understanding how the structure of a certain material (or collection of materials) affect its performance. This is very important when you are dealing with nanostructures, as you can have completely unexpected behaviors due to the extremely small sizes you deal with.
A good example is that of hydrophobicity. This is just a measurement of the degree to which water "sticks" to a certain surface. If you have ever seen a drop of water on a newly waxed car, you will notice that its shape is much closer to a sphere than what you would see on a dirty car, where the shape is much flatter. This is due to the wax on the car being hydrophobic. The amazing thing about nanoengineering is that if you can control the shape of a surface down to the nanometer (1 millionth of a millimeter) scale, you can control the hydrophobicity of that surface.
The idea of being able to understand and use this type of surprising, but extremely useful phenomena, attracted me to this field.
What drew you to ASG?
I learned of the technology that ASG was using, in which we take advantage of the nanoscale shape of the surface to increase the sensitivity of our sensors. Not only is the technology something that I am very interested in, but I was also drawn in by the possible applications.
ASG’s core technology is a silicon nanowire array produced by texturing silicon using metal enhanced etching. What is this structure useful for?
This specific structure is useful for a very, very wide range of applications. In ASG, however, we focus on the increased sensitivity of this structure to things that happen very close to the surface of our devices. This allows us to achieve lower limits of detection (we can detect smaller concentrations) and higher sensitivity (we can distinguish between two very close concentrations). We currently focus particularly on biosensors, which can be used in a lot of areas, such as medical diagnostics.
What can you detect with this biosensor? How sensitive is the method, and why are silicon nanowires better than other sensor technologies?
Right now, we focus on detecting proteins. If we have proteins dissolved in a certain solution, it might be interesting to know which proteins we have in solution, and also how much of each protein we have. In medicine, for example, this could help to determine if certain body functions are working appropriately, or too slow or too fast. We are still working on understanding how much can we take advantage of nanoscale effects to push the sensitivity of our sensors, but the main advantage of nanowire sensors with respect to non-nanoscale sensors is the added knob that we have. By controlling this knob, the exact shape of the surface, we can tune our device to make it more sensitive.
How has COVID affected ASG’s work? Did the company have to change how it did research? Are you seeing increased interest in certain applications?
When I joined ASG on January 2020, we were a very small company, with two full time employees. When COVID hit a couple of months later, with the accompanying lockdowns that followed, we were still able to do quite a bit of work from home. Since there were very few of us, there were quite a few things we needed to take care of, and we made use of those 3 months to do them. However, ASG relies on a lot of work in the lab. In the end, we need to do a lot of fabrication and chemistry which can't be done at home. Fortunately, we were able to resume normal operations after those 3 months. So in general, COVID slowed us down a little, but I don't think we were affected as badly as you often hear from other businesses.
The pandemic has certainly increased interest in the possible application of our sensors as COVID at-home tests. Since our measurements are much faster than many of the currently available methods, if we could tune our sensors to detect COVID proteins, we could in theory have everyone do a self-test before leaving home every day. This would help make decisions on whether it is safe to go certain places a lot easier. Unfortunately, making this change to our sensors is not as straightforward as we would like, so we haven't been able to reach that point.
Last question: If you had to hire a nanobot to do a job for you, what job would you hire it to do?
It would definitely have to be an imaging nanobot. Particularly one with microscopic capabilities (ideally would have resolution in the milli- to nanoscale). Maybe it would send the images to a computer via Bluetooth or something like that. It would be relatively easy to guide this bot through small channels and openings using air or water currents. You could then use this nanobot to see the structure of any surface easily, even in porous materials. You could also use this bot in the body and see individual cells. You could see them growing, dividing, etc., and you could see any damage on certain tissues. This would not only be very interesting from a curiosity perspective, but also very useful in healthcare. Other applications would be to detect and monitor fractures in the parts of, for example, airplanes. This would make flying so much safer!
Andres, thank you so much for taking the time to talk with us today! If you'd like to learn more about the ASG, go to their website at https://advancedsilicongroup.com/.
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