This is kind of a shot in the dark, but I wanted to see if I could get a zeta potential for pnc-Si that was as high as predicted by the electroosmosis results. First I tried to get the membranes to break in 1mL of PBS so that the windows were floating on top of…
This is something that’s been living on my knowledge page, but I think it’s a good idea to put it up here to get some discussion on it. Probstein gives the following equation for electroosmotic velocity in his book Physicochemical Hydrodynamics: U=-εζE/μ where U is the velocity, ε the permittivity, E the electric field, ζ…
I’ve been working over the holiday on trying to make Ag/AgCl electrodes. Here’s the method I’ve come up with so far: 1. 99.99% silver wire is used as the anode (+) and platinum as the cathod (-). 2. Silver wire is coated with chloride in a 1M HCl solution at a constant current of 10…
A few of the newest SC wafers came back with intact samples without any pinholes. First here is a list of the experiments that we want to do in our lab with intact/pinhole free membranes 1. Protein separations – Requires >10 samples per wafer (preferably even more) for replicates of separations in both pressure and…
Even though we don’t have defect free membranes, I wanted to tweak the gold setup using membranes with pinholes. Previously I was using the small scale diffusion chamber that I use for protein separations. This setup has a retentate of 2-3 uL and a filtrate of 60 uL. To do particle sizing using the Malvern…
First off – OK now on to the science. Wafer 747 has a huge amount of pinholes, and in this study I wanted to see how these pinholes would effect electroosmosis. I will show results here from two experiments with these holey membranes. These membranes have a lower rate of electroosmosis than previous tested membranes. …
In the previous post, I used a compound error bar that took into account both image and operator variability. While that seemed to make things a little better, we were still having a problem with w705. I reprocessed a couple extra images from the TEM gallery, and added the differences to the image variability part…
I wanted to attempt pressurized and diffusion separations of brain extract using the new movable wafers. I tried pressure cell separations of 1:20 BBEC (clarified brain extract) at 2psi for 40 min. The flow rates were better than the standards I was previously using – this could be due to the little bit of glycerol…
Previous Post The previous w670 pressurized flow gels showed one trial with a lower cutoff than w673 and one trial with nothing passing through. This experiment was run for 40 min and in each case I saw only 0-3 uL fluid passing. I used the last couple of samples from this wafer to attempt a…
The movable cutoff gels were more or less successful, but were too dirty for publication (see knowledge page). I’ve been trying to rerun them so that they look nicer, but the darker stain that I used has brought out a few new observations. The first gel following this paragraph is the new gel. The second…