Diffusion based separation theory uses a hindrance model to explain how the pores affect the diffusion of molecules of different sizes.  The simplest and most well known hindrance model is given by the Renkin Equation: where Dm is the diffusion coefficient within the membrane, D0 the free diffusion coefficient, and α the ratio of molecule…

I first wrote about quantifying the pore formation process using kinetic theory last year. In this post, I will develop my thoughts a bit more. In the literature, researchers oftentimes present charts, like the two shown below, describing the Arrhenius behavior of silicon crystallization (Sontheimer APL 95 2009). Figures 3 and 4 show the crystal…

I reported last week that a 15 nm silicon film deposited with 05 W substrate bias yielded a highly porous film. This week, I wanted to confirm this effect as well as compare it to films deposited at 10 W and 25 W (our baseline). We find that the 05 W is reproducible and the…

These experiments were conducted during the week of 5/10/2010 – 5/14/2010. To recap on this project, Barrett and I have been working with Dr. Harold Smith in the hopes of developing a drug screening test that consists of small-scale diffusions. In these experiments, we are working with APOBEC3G (A3G), a protein-RNA complex that is active…

In my last post, I presented the results of my BBB TEER experiments.  For the BBB co-culture, there was a spike in TEER.  I hypothesized that this was caused by media acidification by rapidly proliferating glial cells, which in turn negatively affected barrier function of endothelial cells.  When I presented this data to Angela Glading,…

This post presents the data from all of my TEER experiments of BBB co-cultures, with bEnd3 endothelial cells on the bottom and NG101815 glia on the top of PET and pnc-Si transwells.  For all experiments, I used 50000 cells/cm2 as the seeding density.  I always had 3 samples – bEnd3 alone, NG10815 alone and the…

A few weeks ago, I posted some high resolution (100X) images of BBB co-cultures stained with 3 different colors.  I also included the z-height of the different focal planes of cells on either side of PET transwells.  In this post, I present a repeat of this experiment, along with the same analysis performed with cells…

To follow up my last post on air-blood barrier TEER results, I wanted to show some Live/Dead images of these samples.  These are stained after the 14 day experiment. In the following image, you can see normal bEnd morphology on PET and pnc-Si.  Only the cells over the pnc-Si slit are visible because these cells…

I finished 3 independent experiments of air-blood barrier co-cultures – these consist of bEnd3 endothelial cells on 1 side and RLE-6TN lung epithelial cells on the opposite side of the membranes.  We didn’t expect these cell types to potentiate TEER in anyway (like we expected glial cells to tighten endothelial barrier function).  However, our collaborators…

As a continuation of the substrate bias series, I deposited a 15 nm film with 05 W substrate bias and annealed at 1000 C. TEM shows that this condition generates a 13.4% porosity and a max pore size of ~40 nm! Here is a comparison of all the bias conditions tested thus far: I believe…