Bernhard Group: Discoloration was observed during DNA separation experiments. Further study led to these results: No discoloration observed with low pH buffered NaCl. Discoloration with high pH buffered NaCl. Worried that Cl was the culprit, sodium acetate was tested. Discoloration observed with sodium acetate. In one early experiment, 4 areas were tested on one chip. …
Because of the recent discoloration problems I observed with 24 hour diffusion using w670 and 673, I decided to try a shorter time point. 673 had a couple more samples to spare, so I tried an 8 hour diffusion experiment. No discoloration was observed: This is the normal color of the wafer. Slits were not…
While wafers 670 and 673 did not hold up to diffusion experiments, they were strong enough to perform pressurized separations using the pressure cell. Each experiment lasted for 40min, although the average flow was only about 5ul for this duration. 673 has a pore cutoff around 30nm (refer to Dave’s post). The following gel shows…
I’ve processed all the images used in the water permeability studies and found the following statistics from these images: Mean Diameter Mean Area Median Diameter Median Area Porosity Area Weighted Diameter 90th percentile Diameter I calculated the theoretical water permeability for each sample we’ve used and compared that to the experimental permeability using these statistics…
This is the original contact angle study performed using the DeLouise Lab’s Rame-Hart contact angle measurement tool. The entire study was performed on 8/1/06-8/10/06. Observations: Contact angles of non-plasma oxidized samples start ~60 degrees and increase over about 10 hrs to ~75 degrees. Keeping the samples in diH2O halts this gradual increase. Plasma oxidized samples…
Wafers 670 and 673 were made to have different cutoffs. I set up diffusion experiments with two chips from each wafer using protein standards. However after removing samples after 24 hours I noticed that both chips from w670 had fully discolored and the chips from w673 seem to have partially discolored. In all three cases…
In yesterday’s post I showed that I was able to obtain good negative adsorption assay results, but there was one major problem. The cellulose and PES actually had higher protein concentrations after the assay. I suggested this was because they are drawing in water to some extent, but protein was not able to pass through…
The Tecan Nanoquant plate is amazing. For those of you who are unaware, we were able to demo a quartz plate that enabled absorbance measurements with only 2ul drops. It took a little bit for me to figure it out, but it really is a great tool for this kind of study. The ultra low…
Here is the current method that I am following to find the pore statistics: 1. Select the highest threshold that you can still close with disk of 3 2. Hit majority 3. Close w/ 3 4. — Try open w/ 3 5. Erode w/ 3 6. Dilate w/2 7. Dilate w/ 2 8. Erode w/…
This is a retrial of the negative adsorption assay using the Tecan spec/fluorimeter that we have been demo-ing. To perform this assay, I am applying a known concentration to the surface I want to test. After an hour I remove some of the solution and measuring the remaining concentration using absorption and the Bradford assay….