Along with differently sized square membranes, I also designed a wafer with different sizes of slits.  On each chip, there is a 4000, 2000, 1000 and 500um long window.  The thicknesses of these windows are 200, 100, 50 and 25um.  I’m interested to see if there is an aspect ratio that causes endothelial cell alignment/tubulogenesis. …

In my last post on this subject, I showed that cutting off permeability of pnc-Si chips inhibits vacuole formation in endothelial cells.  To do this, I seeded cells on the membrane side, allowed them to attach, inverted them onto a media bubble contained within a cloning ring, wet the well-side with media and then placed…

One of the hidden secrets of endothelial angiogenesis assays on Matrigel is that non-endothelial cell types also form 2D capillary-like structures (tubes) on those gels.  Motivated by this observation, I wanted to look at fibroblast behavior on pnc-Si transwells, specifically with respect to whether or not they formed vacuoles.  Just to clarify – although Anant…

There’s been lots of discussion about “non-porous” membranes and the possibility that they are actually porous.  By “non-porous”, I mean that a TEM of that membrane doesn’t have obvious pores by pore processing/our eyes.  This could mean a couple things: either the pores are so small that they are hard to resolve by TEM or…

The AIM of this experiment was to see the effect of surfaces modified with PEGs (Polyethylene glycol) to protein adsorption. The PEG that I used for the current study is MS-PEG8 (Methyl-PEG8-NHS) which is Amine reactive. Method: For the current experiment I used planar silicon chips which have ~ 142 nm of thermally grown oxide….

I did a small experiment to demonstrate that a carbonized membrane would be stable in a harsh alkaline solution, such as KOH. I soaked a carbonized membrane and untreated membrane in %5 KOH at 40 C for an hour in an oven. As you can see, the carbonized membrane is still in-tact and the untreated…

Inspired by some recent literature that I have been reading, I decided to add an argon bombardment step after the amorphous silicon deposition step by applying a 50 W substrate bias. The idea is that point defects on the surface of the a-Si will become seeds for crystallization and thus lower the crystallization temperature and…

The other (see below) just-to-be-sure experiment I performed this week was to compare staining between 2 different live cell dyes.  I typically use calcein AM to stain live cells green.  This is a membrane-permeant dye which, once inside cells, is hydrolyzed by intracellular esterases to make it fluoresce green.  Another very common live cell stain…

I recently started up another BBB co-cultures and I had a couple of leftover samples.  I decided to use one for a ‘just-to-be-sure’ experiment since I realized that I never did a calcein-Hoechst 33342 co-stain.  That is, I never used a nucleus-specific dye with calcein to confirm that the black holes (vacuoles) in the green…

In prep for manuscript writing I came across a paper that says they’ve created a super efficient EO pump that uses extremely low voltages.  Their top flow rate (.125 mL/(min V cm2) ) is comparable to the flow rates I see with our materials (144 mL/(min V cm2)).  They run their experiments at 3 V…