This week, I did a quick discoloration experiment based on Chris’s comment at lab meeting.  He wondered if soaking the chips in water for a while would allow potential discoloration-causing contaminants to slowly leech out.  I took 2 chips from wafer 622 and soaked them in ~ 300mL DIH20 overnight (with a couple of water…

Here’s some data from my electrophoretic trials with polymer membranes. On this chart, both PES and Cellulose fall on the same line.  In my last post I said that PES membranes didn’t seem to pass water, although I found that I was just setting up air bubbles much easier in this system because of the…

In my last discoloration experiment, I tested buffers with different pKa’s (MES, HEPES, and Tris). I found that only 10 mM HEPES in HBSS caused discoloration, and furthermore, that the HBSS component of this solution was the culprit (post). Fortunately, HBSS is a rather simple solution; it only consists of KCl, NaCl, Glucose, KH2PO4, Na2HPO4…

If protein is adsorbing to a surface, it’s leaving the solution.  We can indirectly measure how much protein is leaving the solution, and that may tell us something about how much these surfaces are adsorobing. For my first attempt, I used the Bradford Reagent to measure the concentration of the solution after protein has remained…

To further investigate the mechanism of discoloration, I prepared buffers at different pH’s and measured discoloration and pH over time. Buffers were: 0.1M MES, pH=pKa=6.1; 0.1M Tris-Base, pH=pKa=8.39; 0.1M Tris-HCl, pH=pKa=8.35; 10mM HEPES in 1X HBSS, pH 7.38, where HEPES pKa = 7.31. This was done in the incubator. Experiment 1: Experiment 2: pH vs….

The Burns-Zidney paper uses streaming potential to measure the zeta potential of polymeric membranes.  This means that polymeric membranes should also be capable of performing electro-osmosis, essentially the opposite of streaming potential.  For more on this, I have a knowledge page that I’m working on entitled Electrophoretic Cell. I punched out two 30kD cellulose membranes…

I ran a few experiments using the stir cell on the shaker table. Diffusion occurs faster on the shaker, but more air bubbles form around the membrane, thus preventing further passage of rhodamine. The first experiment I ran was with .2mM rhodamine diluted from 2mM in a PBS solution. For all of the experiments PBS…

Yesterday, Chris, Dave, Graham and I were (exhaustively) trained on the Asylum AFM in Rick Waugh’s lab.  We had an overview of the basic features of the AFM and got some real data, as well. The top panel is a height image of the pnc-Si chip with the well side down.  Notice the slight decrease…