The last few Tecan posts have dealt with adjusting gain values to optimize fluorescent standard curves.  We now have a general protocol here, and a final standard curve for fluorescein.  Here is the background-reduced standard curve for sodium fluorescein (Na-F) that Christine and I obtained.  This was done with the gain set to 0.000125%, and…

I obtained gold in 5nm, 20nm, 40nm, and 60nm through Mort/Oberdorster Lab.  Separations were performed with fully crystallized samples from SC 073.  Here are sizing and absorbance data: In Water I have tried 24 hour separations in diH2O (SC 073) with these particles.  Here are the results: No 525nm peak in filtrate for 5nm sample. …

Our setup copied Jess’s well in a Teflon block. The chips (SCO21) sat over the well filled with 50 ml buffered (pH ~ 6.0) NaCl solution. On top of the well Paul placed a 20 ml drop of the same solution with DNA ladder added. Two types of ladder were used, referred to as a…

I set up separations of 5nm Au nanoparticles in both H2O and KCl in a new system.  The stir cell isn’t always reliable for separations due to leaking and contaminating (?) particles from the plastic.  To perform these separations, I added 20ul of sample to a sepcon and wetted the backside of the sepcon with…

These are a couple of figures that may appear in the supplementary materials for the permeability paper. The first tries to explain that most of our permeability is due to the largest pores.  The lines plotted are the cumulative number of pores at each size (blue) and the cumulative permeability (green). The lines show that…

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…