We now have a linear standard curve for sodium fluorescein (Na-F) in clear 24-well plates. What is the detection limit? The detection limit is defined as the lowest background-corrected concentration that is 3 standard deviations above the noise of the background. The background here is HBSS with 10mM HEPES. I measured the dilutions a four…
Charles designed a macro for excel to represent the data gathered from wafer characterization, in a visual format. It is built on VB platform and runs off Microsoft excel. The data is input in a simple fashion by selecting the relevant field from a drop down box for columns representing different positions (see fig. 1)….
Now that we have preliminary transport data from the Tecan, we need standard curves in order to get permeability coefficients. This is really tricky because the RFU (relative fluorescent units) are arbitrary and based on the Tecan gain. For example, a solution of 10uM rhodamine might be 5000 RFU with a gain of 80 but…
A study of membrane deflection has been conducted using the Veeco Wyco optical profiler. This is the first time the Veeco has been used to obtain quantitative data describing membrane deflection. This type of analysis will be useful for several reasons: –It will provide a numerical measure of maximum deflection and deflection vs. position for…
The question arose last week about the affects of transport with use of the shaker in the Tecan, which led to a discussion about the current construction of the sepcon. The sepcon layout currently is as follows: The o-ring is 1 mm in diameter. Is this difference between the membrane and the receiver fluid dead…
All of this talk about Zeta Potentials, electro-osmosis and electric double layers got me thinking about these phenomenon in relation to discoloration. We’ve known that salts accelerate discoloration, and we know that bicarbonate solutions accelerate discoloration as well. I explained the bicarbonate issue based on the equilibrium between bicarbonate ions and hydroxyl ions (pH). We…
This is a follow-up to my last post about gold separations. Using the Tecan, I’ve scanned the absorbance spectrum of all the gold particles we posses in water, 10 mM KCl, and 100 mM KCl. Here are the results: The internal peaks are between 515 and 525 nm and are the same for both water…
This is a follow up to Jess’ protein separation post. She mentioned that some of the SC 073 samples were annealed twice: the first was a 700 C 60 s anneal to crystallize (before etching) and the second was a 800 C 5 min anneal to stabilize the membrane (after etching). I took some TEMs…
Two of the newer wafers, SC 073 and SC 074, came back with ~30 intact samples. This would be more than enough for the separation work that I’m trying to finish, so I decided to see if they were any good. SC 073 had an area in quadrant I that was caught in the middle…
Last week, I ran a few experiments to see how certain membrane conditions affected the transport of fluoroscein. The first experiment presented here contained three sepcons: one with 3 pinholes, one with only 1 intact slit, and another without slits to use for the background. The controls were HBSS and fluoroscein. The sepcon with 1…