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…
Given the mixed results of discoloration of RTPed samples from W613, which include no discoloration until 7 days (when the experiment was started within 2 hours of RTPing), and discoloration within 2 days (experiment started 8 days after RTP) I ran another discoloration test. This time I started the experiment within an hour of RTP,…
Below is an image of the PDMS array on the nitrocellulose membrane. I’m trying to create a stamp that can be applied to the NC membrane, before PDMS is poured on. The idea is that the stamp will be heavy enough to keep the PDMS from soaking into the areas of the NC that the…
Last week in lab meeting, someone wondered if there the time after RTP affects the rate of discoloration. To test this, I RTP’ed chips from w638 in Ar at 800C for 5 minutes. I then followed discoloration in DMEM+10%FBS in the incubator with untreated w638 chips as controls. All of the chips discolored within a…
Last week, I did a couple experiments based on a suggestion by Tom. The pH of DMEM starts out quite high and then buffers down into physiologic range after some time in the incubator. Tom surmised that a short exposure of the chips to high DMEM pH might hasten discoloration. To test this out, I…
Hi all, For quite some times we have been trying to design a diffusion-based chemotaxis chamber that operates under an environment of 37 degrees Celsius in temperature. One main obstacle that we face is the evaporation of the 2 uL of rhodamine 6 G (R6G) that we load on the well openning of the membrane…
The ultimate experimental goal of the desalting project is the removal of salts from a salt/protein solution while fractionating certain sized proteins with maximum protein retention and recovery.Thus far we have characterized the flux of salt through our membranes which show flux an order of magnitude greater than cellulose membranes. Our next step is to…
Hi all, After experimenting with UV ozone bonding of PDMS to glass, Si, and pnc-Si for the past few weeks with Mike, we have reached the following conclusions: 1. The bonding of PDMS to glass is always stronger than the bonding of PDMS to Si and pnc-Si, given that all receive same treatment of UV…