After talking with Prahnesh, a graduate student in the Dumont Lab I obtained a protocol for a colorimetric assay used to detect the presence of detergents in solution. The assay uses phenol and concentrated sulfuric acid in the following manner: add 600uL Sulfuric Acid to 40uL of sample and vortex add 200uL 5% Phenol and…
Endotoxins (~10-1000kDa) are structural components of bacteria (LPS is the best known) that are released from bacteria when they die. Endotoxins cause inflammatory responses in humans and animals (infections give you a fever) and in cultured cells. For most cell culture applications, you don’t have to worry too much about endotoxins. For monolayer permeability experiments,…
I’ve been growing brain endothelial cells on PET and pnc-Si membrane transwells for a variety of experiments, but mainly to measure the TEER (transendothelial electrical resistance). TEER is used to track the integrity of cell monolayers grown on permeable supports. As the monolayer gets ‘tighter’, the TEER increases. PET membranes are marketed as transparent for…
I went through and characterized each wafer by thickness and RTP. I graphed “Average Pore Size vs. Porosity” and “Average Pore Size vs. Cut-Off Pore Size” for each processing condition that had at least four representative wafers. ** Yesterday, Professor McGrath and I had a quick chat about the data. I have inserted a few…
Here is the analysis of the wafers used in the pressurized gold separations: SC 199 Stat Result Mean Equiv Diameter 17.84 nm Median Diameter 18.30 nm Porosity 2.2% Weighted Mean Diameter 20.81 nm 90% Diameter 26.64 nm Roundness .782 Separates 10 nm from 15 nm w225 Stat Result Mean Equiv Diameter 18.33 nm…
The electrical properties of 20nm and 50nm thick sputtered oxide is currently being investigated. Capacitance-Voltage (C-V) and Current-Voltage (I-V) tests are achieved by fabricating 200um-4kum diameter capacitor “dots” using Lesker SiO2 targets and flash-evaporated aluminum (CVC). A GCA stepper is also used during photolithography for 5X image reduction. The purpose of the experiment is two-fold:…
Over the past month, I’ve posted some results of a colorimetric assay for silicic acid. Previous posts are here and here. These results showed that the assay detected silicic acid after pnc-Si and PSi degraded. However, bare silicon wafers also yielded silicic acid, according to this assay. Since pnc-Si samples have the Si well-side surface,…
Roundness vs. Equivalent Diameter plots for five eccentric wafers: There really doesn’t seem to be a correlation between equivalent diameter and roundness. However, there does appear to be a rough downward trend in SC 016 and SC 258. Mean Roundness vs. Wafer Number graph with error bars included: Without the error bars, it looked like…
Here are the updated pore processing graphs: The data spreadsheet: pore-processing-results Supplement (added 6/16/09): Here is the Average Pore Size vs. Porosity graph with the outlying data points labeled: After making this graph, I looked at the outliers to see if they were due to my errors. A few were and I redid them, updating the…
In an attempt to minimize flow due to salt gradients, we ran an experiment in which an intentional gradient was used to set up a slight counterflow from the filtrate to the retentate. This was accomplished by having a 55mM NaCl concentration in the retentate and a 45mM NaCl concentration in the filtrate. The top…