Recently, I have been exploring the temperature dependence of post-Si deposition Ar sputtered films (15 nm thick). Below is a comparison of the average pore size, porosity, and density of pores of Ar and non-Ar sputtered films annealed between 800 C and 1100 C. It appears that Ar sputtering increases the avg. diameter and porosity…

In order to validate the salt diffusion test I just posted, I’ve been measuring H2O2 diffusion with SC348 and the Amplex Red Assay from Invitrogen.  I first showed that H2O2 (=34 Da) passed SC348 in this experiment.  Here, I just repeated with slightly different standard curves and positive (‘regular’ Sepcon, SC195 = 4% and 13.9nm)…

About a month ago, I posted some preliminary data that showed NaCl diffusion through SC348.  This was motivated by my observation of vacuole formation on SC348.  Since my hypothesis is that cell culture substrate permeability is the key factor for vacuole formation, cells shouldn’t have formed vacuoles on SC348.  Unless it is actually porous.  This…

For my BBB project, I’ve wanted to get nice images of glial cells and endothelial cells on opposite sides of pnc-Si membranes to demonstrate 1) optical transparency 2) that both cell types are in focus (and thus right on top of each other).  I’ve gotten some images like that in phase contrast but I also…

Membrane chips were amino-silanized with APTES in the YES system.  I performed the standard electroosmosis tests with these chips.  Here are the flow rates in comparison with non treated and oxidized membranes: Here are the calculated zeta potentials: As you can see, amino silane reduces the rate of electroosmosis and the zeta potential. We would expect…

A simple experiment that has never been done is to make a direct comparison between annealing inside and outside the susceptor. Intuitively, we would expect the morphologies to be quite different since the heating mechanism is different for both cases. Inside the susceptor, the film is heated through blackbody radiation from the susceptor. Without the…

I  carried out experiments to test the adsorption of 1 mg/ml of BSA on NHS-PEG surfaces.This time the APTES layer was deposited from solution phase on to the silicon surface in contrast to vapor phase (YES) deposition. Again adsorption of BSA on different layers was confirmed using spectroscopic ellipsometry. Protocol for surface modification: The chips were left…

I few weeks ago, I had a couple wafers made with different size squares and slits.  I posted my first results here and here.  In that experiment, I showed pretty dramatic 2D structures over both supported and free-standing membranes with rectangle shapes.  Also, I showed vacuole formation at (almost) the single cell level on square…

Today I deposited two 30 nm thick Si films and annealed one at 1000 C for 1 min and the other at 1000 C for 5 min. My running hypothesis is that performing an Ar sputter after the silicon deposition creates “broken” bonds that seed crystallization. Therefore, the crystallization should nucleate at the interface and…

In a continuing study on how a post-silicon deposition Ar sputter affects morphology, I annealed three 15-nm films for 10 s, 60 s, and 300 s. If you recall in my first report, I found that the Ar sputter increases the porosity slightly for a 1000 C RTP and dramatically for a 900 C RTP….