All of this talk about Zeta Potentials, electro-osmosis and electric double layers got me thinking about these phenomenon in relation to discoloration.  We’ve known that salts accelerate discoloration, and we know that bicarbonate solutions accelerate discoloration as well.  I explained the bicarbonate issue based on the equilibrium between bicarbonate ions and hydroxyl ions (pH).  We…

This is a follow-up to my last post about gold separations.  Using the Tecan, I’ve scanned the absorbance spectrum of all the gold particles we posses in water, 10 mM KCl, and 100 mM KCl.  Here are the results: The internal peaks are between 515 and 525 nm and are the same for both water…

This is a follow up to Jess’ protein separation post.  She mentioned that some of the SC 073 samples were annealed twice: the first was a 700 C 60 s anneal to crystallize (before etching) and the second was a 800 C 5 min anneal to stabilize the membrane (after etching).  I took some TEMs…

Two of the newer wafers, SC 073 and SC 074, came back with ~30 intact samples.  This would be more than enough for the separation work that I’m trying to finish, so I decided to see if they were any good. SC 073 had an area in quadrant I that was caught in the middle…

Last week, I ran a few experiments to see how certain membrane conditions affected the transport of fluoroscein. The first experiment presented here contained three sepcons: one with 3 pinholes, one with only 1 intact slit, and another without slits to use for the background. The controls were HBSS and fluoroscein. The sepcon with 1…

The highly anticipated 3rd generation etch cell has arrived.  NY Manufacturing did a great job with the design and fabrication.  To give an idea of how far we’ve come, I’ve placed previous etch cells next to the newest. One of the major improvements is the introduction of a drain.  We no longer have to lift…

The AJA sputtering system has 2 oxide targets and 1 silicon target that are focused with stainless steel chimneys.  During our process, films inevitably deposit on the chimney and shutters and after a while start cracking causing flakes of material to fall on the targets. I have noticed that our thinner amorphous films (5 nm,…

A long running side story to my research has been attempted separations of nanogold. The basic idea is that we want to separate EM quality gold nanoparticles with the membrane, but I have had problems detecting gold in the filtrate with the zetasizer. We think this might be a result of the negatively charged gold…

This post is a continuation of the experiments posted a couple of days ago. In that post, I concluded that absorbance measurements of molecules transported through transwells were not possible if the transwell insert was kept in the 24-well during measurement. This was due to absorbance by the outer walls of the 24-well plate and…