I’ve been gathering data for a paper using my microporous MgF2 nanomembranes so here are some sample figures for such a paper. Herein, we are trying to create a porous, Raman-compatible substrate for use in cell culture. Researchers have used Raman microspectroscopy to perform quantitative non-invasive measurements of biomolecules in cells. It’s a very exciting…
I was concerned that even though my calculations for etching the microporous MgF2 material show that the silicon nitride was being removed completely, not all of the silicon nitride was indeed being removed. Hypothetically, the presence of additional remnants of silicon nitride could be causing additional film stress and cause membranes to break more frequently. I…
The title really says it all. I have been attempting to make a better cell culture substrate with the Magnesium Fluoride Films. Previous posts have shown the overall structure of the film, and now I am trying to quantify the strength with a burst pressure measurement. In order to make a direct comparison, I needed to…
The process to create free standing films of MgF2 requires the film stack to survive a few different kinds of stresses. First, there is thermal stress from the mismatched coefficients of expansion (MgF2 expands about 5-10x more than silicon/silicon nitride), the stress of deposition (adatoms not finding their lowest energy position), and other mechanical stesses…
While I have been making nanoporous MgF2 for a while, it has become obvious that the strength of the material is handicapping our ability to generate data; as the membranes rupture we lose weeks of cell culture work. While we have generated some interesting Raman and cellular effects using the nanoporous MgF2 membranes, they are…
Thanks to Sidahmed Abayzeed and Emilia Moradi. Summary: I’ve started making impedance spectroscopy measurements with a potentiostat in the iBidi devices. The data is noisy, but there is a clear change in the curve characteristic as cells grow upon the nanomembrane. NPN seems to be working better than MgF2, for these measurements. I’ve measured the impedance…
We desire to test the electrical perfomance of our membranes in the iBidi chamber. For comparison, I am using a gold standard Ussing chamber format to examine the contribution of our membranes to the overall frequency response of a system. I am using both a matlab model and a web-simulator (www.circuitlab.com) to examine an equivalent circuit model…
Paper: Oo2016 Supplementary Info:Oo2016SI Abstract: Design and fabrication of three-dimensionally structured, gold membranes containing hexagonally close-packed microcavities with nanopores in the base, are described. Our aim is to create a nanoporous structure with localized enhancement of the fluorescence or Raman scattering at, and in the nanopore when excited with light of approximately 600 nm, with a view…
We have previously observed some interesting transfer characteristics of our nanomembranes, using water vapor (breath) to delaminate and adhere them to glass and silicon nitride surfaces. Some membrane transfers do not appear to be stable (fragments or floats away when submerged and exposed to shear stress), while others can withstand shear stress at high rates…
The following images are from ARPE-19 Cells cultured for 3 Weeks over here in Nottingham (thanks for help from Emilia Moradi, Victoria Ciampani, and Kevin Webb). MgF2 nanomembrane chips were positioned into a transwell insert and sealed using PDMS, a biocompatible polymer, creating a two-compartment transwell. After an ethanol sterilization, ARPE-19 cells were seeded in a 12 well…