July 19, 2011

Frustration Anew

We thought things were going to work today, and by all rights they should have.  We had prepared the gold nanobeads last week with a coating of MUA.  The MUA was supposed to have served as a glue to which we would attack proteins, with the goal of making a gold bead covered in proteins.  However, before we could add the proteins we had to first change the MUA with a brief chemical reaction to make it sticky.

We prepared the chemicals and mixed them with the gold.  Instantly we knew there was a problem though; instead of remaining a light pink, the gold solution turned clear at first, and then slightly yellowish.  It wasn't supposed to do that, but we thought the experiment might work anyway, so we continued to the next step.  Now the gold was sitting in a chemical solution, and we needed to rinse it, so we had to separate the gold from the chemicals.  To do this we had to use a centrifuge, which spins the mixtures around really fast like a merry-go-round moving at warp speed.

Centrifuge:

So we spun the gold mixture for a bit, and then took it out.  Imagine our shock when the solution showed no change at all.  I know it's hard to imagine, but this result was about as surprising as if you had shot a pistol at a piece of paper and had the bullet bounce back at you!  Thinking that maybe a higher setting on the centrifuge would fix things, we set it to it's maximum speed and let the gold solution stay in it for 20 minutes.  The gold particles were feeling a force roughly 16,000 times stronger than gravity, so surely they would separate from the solution this time.

They didn't.

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