User:Brian P. Josey/Notebook/2010/02/19

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Great News! The magnets came in today after lunch. All I have to say, is dang, these little guys are strong. We ordered two small conical magnets. They are each a half an inch in both height and diameter, and are made out of neodymium and very, very strong, easily stronger than the small cylinders Larry uses. Luckily, for reference, the tips are polarized so that the south pole is at the peak of the cone. So far, I can only find one issue with them, because of their size, they don't fit inside of the yoke without touching the machined tip on the other side of the gap. I am going to try both the micro-tube and flow cell experiments today, and to see what I can get out of them.

Flow Cell

I created one flow cell containing a little over 10 uL of the 1:10 dilution of ferritin in water that I created earlier. Unfortunately, I didn't press either the tape down enough, or something along those lines, and the flow cell started to dry out. I decided to make the best of this, and place the tip of the cone on a specific place on the flow cell and let it dry. My idea is that after the flow cell dries out, a deposit might be left over where the cone magnet was. It's not the best idea, but I am making the best out of a poor flow cell. The real experiment is down below.

Last night, I was trying to come up with some ideas of how to visualize the ferritin. While in the flow cell, the ferritin solution is almost colorless, having only a very slight orangish-brown color. I've tried looking at it on both the counter top, which is black, and on one of the chemical wipes, which are white. The best so far is putting it on the counter top, this gives the best contrast. But I was also thinking about putting the flow cells into the yoke. Originally, I thought I could have a very large gap between the magnet and the machined tip, and lay the flow cell flat so that the field lines ran parallel to the flow cell, and across the middle. Unfortunately, the large gap will weaken the field, and give very little space for a color gradient. I then debated doing the same thing, but with a smaller gap, and ruing the field perpendicular to the direction of the flow cell. It would be better, and could potentially create two spots where you could see the ferritin clumping up. I also flirted with the idea of wedging the flow cell between the machine tip and the magnet, but that wouldn't work because there is such a small gap it would shatter the glass. For this last idea, I would need a yoke that would have a gap large enough that the cone magnet, and the flow cell could fit in sideways, without the two tips touching.

For the second flow cell, I am going to be really careful, to ensure that there is no possible leaking, and that it cannot dry out. Then, I am going to rest the slide onto something, so that I can rest perfectly with the tip of the magnet touching the coverslip. This will create the smallest possible distance between the ferritin and the magnet (the thickness of the coverslip). I am also using 10 uL of the undiluted ferritin, to get the most protein into solution as possible.


My first flow cell, where I let it dry out, did not work at all. To be fair, I didn't expect it to. The only weird thing though, was that it looked like the bubble was drawn to the magnet. However, I think this is the result of the water being attracted to the sides of the flow cell (adhesion?) and it is only wishful thinking that I noticed it in the first place.

For the second flow cell, I had the slide oriented so that the cone magnet was touching the cover slip from beneath the set up, as described above. After letting it sit for about ten minutes, I didn't notice any noticable change. Unfortunately, I cannot repeat this one, or let it sit longer today. On Monday, I will set up the exact same set-up as soon as I get in after class and let it set for a while.