Last week, Barrett and I made up the three buffers needed to perform this test: Dissociating buffer: 0.1 M glycine-HCl, pH 3.5 1 M Tris Binding buffer: 0.1 M sodium phosphate, 0.15 M NaCl, pH 7.5 In addition, I made a solution of protein A beads that consists of 0.0166 g of beads in 50…
Follow up to this post. As a brief reminder, I have performed 3-D simulations of separations in large and small volume systems. I have defined an effective diffusion coefficient that takes into account the membrane hindrance and compared this to free diffusion. As the Deff/D0 ratio drops, this means the membrane has a higher impact…
With the previous 2 experiments, I made a couple of 6-slit pnc-Si transwells. These chips were from the cell culture wafers I had made a while ago. These samples (SC126) were RTP’ed before use. My improved technique, combined with the RTP, enabled me to keep cells growing on these pnc-Si samples for 1 week WITHOUT…
Along with the PET data I just posted, I also examined cells on pnc-Si transwells. The following images were taken at 20X (through the bottom of a 24-well plate), and the cells are passage 8 bEnd3. They were seeded on the membrane side @ 100000 cells/cm2, and then the transwells were flipped for growth. Images…
A while ago, I posted some images of cells grown on commercial polyester (PET) transwells. Here’s the post. I found that there was an annulus of dead cells around the edge of the transwell when cells were grown on the bottom of the membrane. I contacted Corning and they said that these dead cells were…
Recently, SiMPore has been exploring alternate ways for depositing our film stack. We’ve finished our initial testing of a plasma-enhanced chemical vapor deposited film by Rogue Valley (OR), and it appears that the pore formation process is inhibited with the standard 1000 C RTP 100 C/s anneal. The most striking difference (besides the difference in…
I asked Tom to add gold PES separations of NPs to his earlier figure and to evaluate the loss of NPs during the use of these filters compared to pnc-Si. Here is what he came up … All experiments (including pnc-Si) were done at 10 PSI with 200 ul of starting material above the membrane…
This device was built similar to the device featured in the Burns(Zydney) 2000 J. Mem. Sci. paper. Our device seals in a SepCon formatted pnc-Si chip and allows 2 electrodes to be positioned by the chip. A feed line pressurizes the chip with saline, and the generated potential can be measured using the electrodes. The…
In preparation for Tuesdays meeting Jim asked me to prepare this chart to compare the results of the treated and untreated diffusion experiments from this summer. The chart values given are the percent concentration of the sample filtrate in comparison to the original “feed” solution. For instance in all of my experiments the initial “feed”…
In the previous post it seems that the membrane pores do not significantly retard proteins and that the separation characteristics are due more to the slower diffusion coefficients of the proteins. However, in certain circumstances, the membrane may provide more of an effect. All of these experiments and simulations took place in a relatively large…