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…
We received W648 from the production team this week. Upon inspection of this wafer, is has a higher density of pinholes than we have been seeing lately (>3 pinholes/slit compared to 0 or 1/slit) and seems to show a return of contamination, shown below. This contamination is visible over the entire wafer, but is easiest…
In this week’s meeting there was a request to have Maryna and I make our BP and AP data available online. While Maryna is at the Gordon Conference I thought I would upload what I have. The attached spreadsheet contains two tabs, one for AP and BP. Wafer number and position of each test sample…
I recently repeated a chemical stability test of RTPed (5 min in Ar at 800C) samples from W613, which has the 30 nm pnc-Si layer. In this study I used DMEM +10% FBS as the culture media without cells. Previously RTP treatment of samples from this wafer survived about 7 days. In this iteration of…
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…
Due to our desire to improve membrane stability in cell culture, different methods of treatment have been mentioned to try, including carbonization and silanization. W606 was treated with UV/ozone at 150C for 20 minutes, followed by silanization performed by some of Chris’ colleagues. I then ran a basic discoloration test in DMEM +10% FBS (the…
Previously W514 was tested with different RTP conditions (varying time at 800C, all in Ar); the results were difficult to interpret as the cells were confluent (in some cases it was hard to see membrane breakage). We therefore decided to run a similar test again, with a slight change in O2 addition during RTP. O2…
Previously I ran a chemical stability study of samples from W613, which has a 30 nm thick pnc-Si layer. In that study complete failure of untreated samples was observed by 18 hours in cell culture, which was not a significant improvement from sample lifetime of 15nm thick pnc-Si. To see if RTP treatment helped the…
Spreading of cells (huvec and fibroblasts) on pncSi and glass was observed at ~37 C in L15 media (+ 10% FBS) for ~5 hours. Its observed that the cell spreading is pretty similar on both the substrates and the time lapse movies can be seen from the following links: huvec_glass_sprd huvec_membrane_sprd fibroblast_glass_sprd fibroblast_membrane_sprd Somehow its…