We performed four hours of sham dialysis, using two non-porous nitride membranes. The set-up is described in an earlier post. Blood samples were taken when the animal was received, after one week of the adenine containing diet, then at 1 hour intervals during the dialysis. The data shows that the urea level, which was increased over…
This is part of our work studying how cells adhere, spread and proliferate on varying pore size/porosity SiO2 membranes. This post will be a qualitative look at how HUVEC spread over membranes by staining for actin filaments. In a future post we will quantify the degree of spreading at 1hr, 4hrs and 24 hrs. Calculation…
These chips were 2.9 mm TEM grid with a single 25 um window. 20 nm thick NPN is covered with 100 nm TEOS with a 2 um opening to expose ~1000 pores. Wafer number 2176. Following are IV curve analyses for the above material as well as membranes treated with ALD alumina. These were measured…
This is part three of a series of posts on constructing a mathematical model of the movement of gold through a porous membrane. In part one, I implemented William Deen’s mathematical model of the electrostatic and steric effects that contribute to whether a gold nanoparticle will translocate through a pore. The mathematica and matlab code…
See my previous post for background information. It has been established that diffusion of small particles (diameter < roughly 1/3 pore diameter) across ultrathin membranes is mediated almost entirely by the ability of the particle to discover a pore, rather than by its ability to diffuse through a pore once one has been found. In…
Meghan and I continued to experiment with our PLA printed transwells. We came up with a protocol that has some cells growing on pnc-Si (albeit not to confluence yet), and less so on nonporous Silicon nitride. In the gallery below B2, B3, and B4 are 1060 nonporous silicon nitride SEPCONS (cells in trenches) and B5…
Prior to my qualifying exam about a month ago, I put together a simple model of transport (detailed in this previous post) across a nanomembrane that incorporated electrostatics as well as terms describing both convective and diffusive transport across the membrane. It was a useful model, but ultimately limited, as shown by the following image:…
Below are various SEMs of NPN membranes. (All samples were coated with metal by using the Denton Ag sputterer for 120 s) These were used samples that have been sitting out in the lab for weeks. I don’t remember the exact details of the processing. I believe they were filters we used to test the possibility…
For a while now I’ve been working on developing and testing the practicality of using nanoporous membranes as filters for highly sensitive assays. Traditional filter-based assays are restricted in their speed by both the time it takes for a particle to find a pore as well as the time it takes for the particle to…
Bob and I are trying to determine which wet etch would be appropriate to use to remove the native oxide inside the pores before membrane liftoff. The issue is when removing the native oxide, we will remove part of the membrane. So far, we removed native oxide from bare silicon wafers using 50:1 HF. For…