These are cross sections of my comsol diffusion model. Each chip has 6 square wells terminated in a membrane. This cross section cuts across the two middle wells. Concentration contours are in 0.025 intervals. 6 hours: 12 hours: 18 hours: 24 hours:
Over the last couple of weeks, I’ve been doing confocal fluorescence microscopy over at the Med Ctr. I was hoping this tool would clean up some of the background fluorescence in my immunofluorescent images. More importantly, the confocal can take ‘slices’ of images in the z-plane and stack them on top of each other to…
As a proof-of-principle, Henry and I have been working on a microfluidic device for flowing blood cells/particles across cultured cells on pnc-Si. More on why this is important later. We’ve come up with a prototype and I’ve been testing it out. I will include schematics later but here are the first couple of movies I’ve…
One of the points I’d like to discuss in my co-culture paper is the advantageous imaging qualities of pnc-Si compared to ‘translucent’ commercial transwell membranes. This has been evident in many of my posts of Live/Dead stained cells, even at 20X. I thought a higher resolution (100X) image would emphasize this point even more since…
In order to figure out the relationship between grain size and pore size, I tried to use XRD measurement to determine the grain size by Scherrer equation. t = kλ/(B cosθ) where t is the average grain size, k is the shape factor that is in the range 0.87-1.0 (it is usually assumed to be…
I’ve been trying to get multi-color images of endothelial cells and glial cells on transwell membranes in order to compare image quality on glass, pnc-Si and polymer membranes. Specifically, I’ve tried staining endothelial cells green with VEGF mAbs and glial cells red with neurofulament H (NFH) mAbs but VEGF expression in bEnd3 cells is extremely…
Those with a great memory will remember that I’ve been struggling (1, 2, 3) to identify adherens and tight junction proteins (i.e., cadherins and ZO-1) in bEnd3 endothelial cells. Since I’ve recently moved over to investigate air-blood barrier co-culture models, I decided to see if my epithelial cells (RLE-6TN) express cadherins (they should since these…
This figure is a potential response to Reviewer’s 1 question about the difference between pore discovery and transmembrane resistances and Reviewer’s 2 question about membrane vs. well resistance. a. Resistances for an ultrathin membrane with large pores. The pore discovery resistance is larger than the transmembrane (steric/frictional) resistance for small molecule sizes. The total resistance…
Our collaboration with Alison Elder, et al. in the Dept. of Environmental Medicine has led us to talk about developing a co-culture model of the air-blood barrier. This barrier is ‘located’ at the alveolar sacs in the lungs, where lung epithelial cells in the alveolar space are exposed to air. These epithelial cells are separated…
One of the reviewers for the diffusion based separations paper was concerned that there would be osmotic pressure which would cause convection across the membrane. Previously we have been aware of osmosis in the DNA experiments by Paul Black and Bill Bernhard, although their results were due to a salt imbalance if I recall correctly….