I tried to measure the thickness of the non-carbonized and carbonized membranes for the paper using SEM. To have a clear cut of the membrane I place the membrane chip upside down on a silicon wafer piece, then bend the membrane chip with tweezers so the membrane sticks to the wafer while breaking of the…

I recently began working directly with Dr. Harold Smith’s A3G protein. In my previous posts,  I worked with BSA and IgG in order to develop a small-scale diffusion set-up able to reach equilibrium before it dries out. These preliminary steps were working towards my ultimate design for a quick and accurate diffusion set-up for A3G….

Vascular endothelial growth factor (VEGF) is one of the important growth factors/signaling factors that affect endothelial cells.  It is involved in angiogenesis, vessel regrowth during wound healing, vessel development and other vascular functions.  Since this is the most commonly studied growth factor in in vitro angiogenesis assays, I’ve been thinking about it for awhile.  If…

In all of my experiments involving vacuoles, I’ve seeded at 50000 cells/cm2 which gets the cells to confluence after ~ 1 day of growth.  I’ve always seen vacuoles with these parameters.  For this experiment, I wanted to see what the cells would look like after 1 day but at a much lower seeding density.  The…

A couple months ago, I tried to use tetramethylrhodamine (TAMRA) as a fluid-phase marker to label vacuoles.  The idea is that the only way this stain could be internalized is if it is pinocytosed, eventually ending up in vacuoles.  If you follow this link, the dye worked OK but not great.  I found a couple…

It’s been a while since I’ve done long-term BBB co-culture experiments on transwells but I recently completed a study.  I was particularly interested to determine whether I could reproduce this spike in TEER that I measured in 1 previous experiment. I also needed repeats anyway. I followed the normal procedure – seeded P11 bEnd3 on…

Last time I cultured fibroblasts on pnc-Si transwells, the cells got super-confluent over the membrane and made the analysis difficult.  Basically, I wanted to see if fibroblasts formed vacuoles/2D structures over free-standing membranes.  I thought the multi-layer cells could have choked off permeability and prevented the higher layers of cells from even sensing that they…

I’ve always suspected that the pore formation process was very quick and to confirm this I looked at a wafer that was annealed for 10 s vs. 60 s. From the distributions, it would appear that the majority of pores nucleate and grow during the ramp and first few seconds of steady state. Next, I…

The goal here is to see if by using our membrane we can measure and separate different pore wall interaction effects of gas molecules passing through a pore. First, some theory. The flow through every pore of particular aspect ratio (L/d) is determined by pore’s transmission probability value (W), which is the probability of the…

Here is an attempt at the active area figure using the “newer” EO membranes (SC172).  Here is the raw flow data for the three membrane sizes: If we take the slopes from this figure, we get the flow rates in uL/min.  We can then plot against active area: We get a pretty nice fit here,…