Because of Harold Smith’s project, Rachel and I have been working on various methods to get proteins through a pnc-Si membrane and onto a polymer membrane. The particular system that Dr. Smith wants to study is very sensitive to ambient RNAses, molecules that digest RNA. This means that the long times required for a diffusion…
I’ve been learning the discoloration protocol from Karl and Anant and finally have some pictures of my own to show. We got a couple of new media (RPMI and DMEM/F12) last week in order to grow the cells I’m getting from the Elder lab (rat lung cells). I did a discoloration test to see if…
Today Barrett and I processed SiO2 deposition at RIT. This process was actually delayed due to the cleanroom scrubber failure last week. We deposited 30nm SiO2 on both sides of three wafers, #335, 341, and 345. Earlier in March, I tried 20nm and 40nm SiO2. It was found that 40nm SiO2 is so thick that…
One question we recently had was what does it look like when we perform a separation experiment when a membrane has a pinhole. I selected two membranes off 621 that appeared to have pinholes on both slits. I applied 1:2 standards to the top and allowed to diffuse for 24 hours. I collected the retentate…
In order to support the idea that RTP treatment does not change membrane pore characteristics (as shown by Anant in the rhodamine diffusion study) I processed TEM samples that were not treated, RTPed in Ar, for 5 minutes at 800C, and RTPed in O2 at 800C for 5 minutes (I believe this was not a…
Dave delivered W637, a wafer made using the sample recipe as W504, to us today. This wafer has a high occurrence of single pinholes, with only 12 samples pinhole-free. I also noticed some odd features on the membranes, shown below. In the reflection images above, some sort of substance is on the membrane. In the…
Last week I tried to diffuse Cytochrome C through our membranes onto PVDF and PES membranes to see if we can detect protein adsorption on the other membranes. The trial illustrated that cytochrome c will diffuse through our membranes and stick to the PVDF and PES membranes. I ran the experiment again, but I used…
The 20nm deposited polymer film permeability is approximately 1e6 barrers, while bulk polyimide permeability is less then 100. So the experimental value is too high. There are two possibilities to explain it: First, the pores are partially open and 20 nm thick layer is too thin to cover big pores. I will try AFM this…
I’ve been working with the Corning transwell inserts and our SepCon units a bit recently. The addition of the Dremel last week has allowed better control while cutting the transwells, even without the right angle attachment (which will allow cutting in the “drill press” mode). I attached a picture of the process and final unit….
Bill Bernhard’s group approached us about using pnc-Si membranes to separate DNA species by diffusion. Bill’s lab studies the effects of ionizing radiation (ex. X-rays, gamma rays, UV light) on DNA using electron paramagnetic resonance (EPR). There are three major species of DNA that they wish to study using our membranes: short oligonucleotides, larger supercoiled…