Pint Silicon Supercapacitor Tejas sent me an interesting article about Silicon-based supercapacitors. I have made a previous post on potential uses for our membranes as separators in EDLC (electrical double layer capacitors), and one of the problems I posited was that the electrolyte chemistry seemed particularly inimical to silicon (KOH, Na2SO4). The authors in…
While performing an experiment to study HUVEC growth rates on various substrates, I observed an interesting phenomena on the oxide membranes. I was using 120nm, nonporous, 600C annealed SiO2 membranes in this trial. The cells were observed at least once per day over a course of 173 hours from seeding. The growth rates and quantitative…
I used COMSOL for finite element analysis (FEA) modeling of EOF and DEP at a microporous membrane in a PDMS microfluidic channel. Effects of two parameters were determined: Membrane thickness, and spacing between pores. The modeled membranes had a 25×25 um surface, and a thickness of either 100 nm or 500 nm. Pore diameter was…
We have successfully plated adipose derived stem cells (ADSC) on microporous silicon nitride (SiN) membranes. Cells plated on nanoporous SiN appeared fine at time of seeding, but membranes were broken at 2 hours – possibly due to media washing or cell spreading/contracting. Josh Miller made new Microporous and Nanoporous Nitride liftoff membranes. These membranes were…
Michael and I have been working to create cell channels of varying widths and heights to test out a concept used in a paper we recently read as a group. This work claims to see cell cords in 12 hours, so no media renewal is necessary. The channels were made by layering and bonding…
A few weeks back I had finished my streaming potential/electro-osmotic pump setup. It looks like this: For streaming potential measurements, we pressurize a tube filled with 100mM KCl that connects to the membrane and measure the voltage drop across the membrane. When I first applied a pressure to the setup, the voltage drop did seem…
Method: Oxide membranes in some conditions have been shown to wrinkle over time. To study this, three different varieties of SiO2 membranes were observed (1000C nonporous 120nm SiO2, 150W deposited microporous low-density 300nm SiO2, and 100W deposited microporous low-density300nm SiO2). Beads were placed on the top of each membrane and given ~24 hours to settle…
Below are the results of my recent crosslinking efforts. PEG with 1.5% crosslinker was exposed to UV light at varying times through a bar printer/transparency mask measuring 100/200. In theory this corresponds to 100 micron PEG bars and 200 micron openings. In practice the results are much less neat. The table shows HUVEC cell attachment…
Scope: Adipose derived stem cells were seeded onto Corning 3um tracketch membranes, human endothelial derived stem cells were seeded onto the membranes approximately five hours later. Numerous control wells were also seeded with ADSCs both on membranes and on the bottom of the 24 well plate. Three days after being seeded, media in each of…
Over the past week Andrea and I designed a new co-culture support structure for use with SiMPore’s 5.5 mm square membranes. The devices are built for use in standard 24-well plates and should prove useful to anyone wanting to do basic co-culture with these membranes going forward. The device is constructed of PDMS rings as…