In 1955 while addressing the National Academy of Sciences Richard Feynman stated "Scientific knowledge is a body of statements of varying degrees of certainty." As usual, Feynman's statement was spot on, and holds true decades later. In his famous "Plenty of Room at the Bottom" lecture Feynman talked about what we now call nanotechnology, and all the different applications. Here I am, half a century later, working "at the bottom" and living in a world of uncertainty. I hope to share some of the exciting discoveries at the nanoscale and explain how they apply to my passion of biotechnology- as well as the everyday world. Learn more about Nicholas Fahrenkopf
My posts are presented as opinion and commentary and do not represent the views of LabSpaces Productions, LLC, my employer, or my educational institution.
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Before I get started with my summary of Day 2, I need to vent a bit. As a presenter 99% of the time you are not loud enough to not use a microphone, so please don’t try to forgo it. Also, 99% of the time you will cover 1 slide per minute. So, a 15 minute presentation should not have 40 slides. You will never cover all of that material. Please rethink what point you want to get across. I’m constantly disappointed by folks who have the fly through their results due to poor planning. I’m also disappointed when chairs don’t stick to the schedule. There are multiple sessions all over the place so when I show up at 10:15 to see talk X and you just started talk X-1 because you’re running 15 minutes late, that means I can’t see X and still make it to the 10:30 talk in a different session. The times are more than a suggestion!
Moving on, this morning I spent most of my time in the biosensors session. There were some really cool ideas. One researcher made an array of divots in a surface and through a controlled capillary action deposited a magnetic particle in each divot. He then introduced more magnetic particles and a magnetic field to make these pillars of magnetic beads that could capture functionalized magnetic beads that were bound to circulating cancer cells. I’m not sure how the whole assay worked but I feel like there must be an easier way to filter of magnetic bead-tagged cells than these assembled nanoparticle-pillars. But it was still pretty cool self-assembly.
This was the first time, although not the last time, that I started hearing about how expensive microfabrication is. This really confused me because I’m used to microfabrication as being the quick and cheap way of making things. I found myself asking “expensive compared to WHAT?” Sure, a cleanroom is expensive, but how else can you reliably fabricate the same device billions if not trillions of times in a single go. Many times I wasn’t convinced the proposed solution was even any cheaper! An exception was this group from UT Dallas that made gold electrodes in a cleanroom to create SAMs and immobilize DNA and study enzymes that act on the DNA. Their non-cleanroom solution was to electrospin fibers, then coat them with gold nanoparticles, and then continue with the SAM and DNA. That was fair. That is a method with comparable ease, and likely much cheaper. It may not be as reliable or saleable but for what they were doing it worked, it was cheaper, and just as easy as working in the cleanroom.
The second AM talk was a research who had four different nanowires on a die (different materials I mean) that each had differing degrees of a response to different analytes. NW1 might have a big response to analyte A, small response to B and medium response to C while NW2 had no response to A, large response to B and small response to C, etc, etc. Then, using principal component analysis when you get a response WXYZ from the four sensors you can work backwards to figure out what the analyte is and the concentration. Pretty cool but I held my breath when I heard him talk about “mass production”. You see, my talk was about making significant steps towards mass production, so when I heard others talk about it I was afraid of being scooped or being irrelevant. But similar to the “wafer-scale” CNT devices, and the “expensive microfabrication” the “mass production” was a relative term. Maybe this development was closer to mass production but in my mind any time you use an electron beam tool you’re not ready for production. No one is going to pattern wafers with e-beam lithography. It is prohibitively slow for production.
A really neat biosensor trick I picked up though involved shadow masking before oxygen plasma treatment. Basically, we make our sensor devices, immobilize our biomolecules, and then need to encapsulate the sensor into a microfluidic chip. To do that encapsulation you usually oxygen plasma treat both the sensor and the fluidics and squeeze them together to bond them. Think of it as putting glue on your table and along the rim of your glass. When you flip the glass upside down on the table the two with stick really well. However, instead of glue we’re using oxygen plasma, and instead of an empty glass that glass has sensitive biomolecules in it that do NOT like plasmas. So, what you can do is basically cover the sensor with a patterned piece of aluminum that covers and protects the biomolecules during plasma, but lets the rest of the sensor get treated with the plasma. It might seem like a really simple solution but it is a really great idea.
The last thing I want to mention is paper microfluidics. The concept of lab-on-a-chip requires microfluidics channels to move your sample and other reagents around on your chip. George Whitesides has been one of the pioneers of soft lithography and microfluidics that 90% of the people doing this kind of work use. So I was interested when I heard about paper microfluidics that (of course) Whitesides has been revolutionizing as well. I get the concept: build your sensor on paper and its cheaper and the reagents can move around by being “wicked” around. So when there was a talk about paper microfluidics I was really excited to hear more about it. Sadly the gentleman had too much intro that we never really heard about his results.
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