I sealed track etched membranes into the usual E-Cell setup. Here’s a chart with the calculated flow rates: I’m not sure why the 50nm sample was so much higher. Maybe there’s a difference in porosity? Also this is only the first try at this experiment. Here’s a chart with flow rates of all the experiments…
We have two cutoffs for the Millipore Biomax PES membranes: 50kD and 30kD. I tested the “EO” rates for both of these membranes and plotted them in this figure with standard deviations (3 trials of 50kD and 4 of 30kD). 50kD has a significantly higher rate of “electro-osmosis.” I will try to compare these rates…
Here are the results of a protein ladder separation with w677. If you recall, 677 is the 200um wafer that did not fit into the SepCons but had very few pinholes. S = Standards Ladder, C = Protein solution that never came in contact with membrane, R = Retentate, F = Filtrate Myosin (Band at…
Does more active area mean more fluid transported by electroosmosis? To test this I found an ancient wafer (w13) that had different active area geometries. Can someone check and make sure I got these right: Long slit – .1 x 1mm Short slit – .1 x .5mm Point – .1 x .1mm 3×3 Point Array…
This is a retrial of the previously outline negative adsorption assay. I was a little more careful with cuvettes this time around (there are very significant differences in the plastic cuvettes) and I spread out the same amount of solution over a larger area. If exposed to more surface, more protein should adsorb and leave…
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…
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…
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 used the source meter that Chris brought over and tested the voltage at points across the chamber. I set up the system with 1x PBS at 15V (~10mA) with a pinholed membrane. I tested the voltage drop at the outer edges of the well, in the center, and the inner edge of the chamber…
I guess we weren’t sure if I was actually drawing rhodamine back through the membrane or just bleaching it. So I made a new apparatus which consisted of a sawed off sepcon mounted on a slide with channels etched into the lower plastic of the device to connect a pbs resevoir on the slide to…