Four different post-production treatments with the objective of improving membrane stability in culture were run last week on W615, a pinholed wafer laden with the circular features we have been seeing recently. I ran four different conditions for cell culture: no treatment (n=3) UV/ozone for 5 minutes at room temperature (n=4) RTP in Ar for…
Diffusion of rhodamine was observed through pncSi samples from W620. This was done to compare the porosity of the membranes after RTP treatment. From the following movies (real time = 10 mins) it can be seen that there is no significant difference in diffusion between the samples after they are RTPed, as expected. Now, Henry…
After doing all the water permeability with this wafer, I saved the samples to do some protein studies. When I write my own paper I will need two wafers to separate protein standards by diffusion and flow to show movable cutoffs. I will also include a brain extract separation to make the point that you…
Yesterday Henry and I went over to RIT to perform anodic bonding and parylene deposition using the new membrane configuration of W619 (with the etched trenches for our capillary tubing). I just wanted to post a summary of the process that was done yesterday, as we encountered numerous problems, in the hopes that we can…
Today I etched wafer 621, which is the pair to 620. While w620 has a relatively low pinhole density, w621 shows a much higher occurence of defects. Since the front-end processing and thermal treatment was identical for these wafers, I believe that the variability lies in the etch process. Looking at the two wafers side-by-side,…
So I talked a bit with Philippe today about the water permeability data, and he suggested that I try to see if there’s a correlation between what the histogram looks like and the experimental permeability’s relation to the theory. I pulled out all the histograms and here’s what I could find. Two of the membranes…
Art is going to make a second stir cell this week. I asked him to replicate it as closely as possible, however I’m not sure how well that’s going to work. The one we currently have is made out of Ertalyt, a material similar to teflon. Paul gave us polyethylene which is much softer than…
W613, the wafer with 30 nm thick pnc-Si was tested for chemical stability. This wafer was shown to be very weak mechanically, with burst pressures less than 1 PSI. I tested this wafer for chemical stability with cells (fibroblasts, P26) in DMEM +10% FBS (n=5). I also monitored discoloration in DMEM +10% FBS w/o cells…
I’ve been working on trying to fill in some of the blanks of the permeability paper, and I’ve been fiddling with the water permeability data. I plotted the old water permeability data as a scatterplot, and while there looked like they could be a linear relationship with porosity, it was definitely missing some medium porosity…
Following the advice of Dave and Chris I ran a UV Ozone bonding trial yesterday with the stage temperature set to 100C (instead of the usual 25C). The idea behind the elevated stage temperature is to drive off any water vapor that might be within the UV Ozone chamber during the treatment process. At the…