Because of the disagreement between the experimental and simulation comparison in this post, I decided to take a look at the Sterlitech membranes using SEM.  Barrett gave me a hand with all the images, and we tried to look at the edge for thickness and the pores for density/overlapping pores. In this first image, the…

Another one of the questions I’ve been trying to answer with regard to endothelial cell vacuoles is whether membrane mechanics or permeability drive vacuole expression.  I’ve thought of several experimental designs to test this that haven’t worked (i.e., using very small volumes on the apical side to minimize permeability, using PDMS plugs to block the…

Last week, I annealed a few amorphous 15 nm TEM grids in the RTP.  We have always speculated that the stress from the bulk silicon was a necessary condition to induce pore formation and I wanted to confirm this.  I picked six different temperatures: 600, 700, 750, 800, 900, and 1000 C.  They were annealed…

One of the ongoing efforts with endothelial cell culture on pnc-Si is to confirm that the holes in these cells are actually vacuoles.  In my last post, I tried to do this with FITC-Dextran and TMRIA with indefinite results.  I ordered some 5-6-carboxytetramethylrhodamine (TAMRA, C-300 from Invitrogen) to do this test again.  This rhodamine dye…

Tom recently designed a wafer with 1cm2 chips containing a 2×2 array of 1mm2 square membrane windows that fit on 384-well plates.  I wanted one of these chips to get a preliminary data image for my R21 application.  Instead, I saw something much cooler. I plated bEnd3 cells on the pnc-Si side of this chip…

In this post I will describe the use of the 3-D computational diffusion model as applied to separations with thick membranes. Experimental:  Track etched membranes were trimmed to fit into round plastic sepcons and were sealed in the traditional way using an o-ring.  20uL of protein sample was pipetted inside the sepcon and 20uL of…

My previous 2 posts on co-cultures presented images but I also tracked the TEER in these experiments.  This post shows that data. The top 2 graphs are from the 1st co-culture experiment – the bottom graph is from the second experiment (where my PET controls died), as % Day 0: On PET, the coculture TEER…

In my last post (the first co-culture), I showed that bEnd3 cells exhibited a different morphology when they were co-cultured.  I also decided that I would reverse the orientation of the co-culture in order to better visualize the endothelial barrier.  That is, grow bEnd3 on the basolateral side and NG10815 on the apical side of…

This post presents cell images from the first successful co-culture experiment.  I seeded P8 bEnd3 cells alone, P13 NG108-15 cells alone and both cells on PET and SC500 pnc-Si transwells.  For this experiment, I seeded 50,000 bEnd3/cm2 on the apical side and 50000 NG108-15/cm2 on the basolateral side of the transwell.  I tracked TEER (future…

One of the themes in my recent posts has been the presence of ‘vacuoles’ over free-standing pnc-Si and PET membranes. We’ve assumed these are vacuoles because endothelial cells form vacuoles, they don’t stain with live cell stains (and so have no cytoplasmic enzymes) and there can be several of these structures in each cell.  In…