I’ve been wondering if there were differences in actin/cytoskeletal structure of cells on supported vs. free-standing pnc-Si. A couple weeks ago, I had a couple of extra pnc-Si transwells so I stained for actin. I followed the actin staining (rhodamine-phalloidin) method I uploaded to the protocols section of the lab, and I counterstained the nuclei…
A couple weeks ago, I showed some preliminary data on H2O2 detection via the Amplex Red Assay, which is a project for one of our high school students. This generated some discussion at the last NRG meeting about diffusion through “nonporous” membranes. Jess wanted to look at very small molecule diffusion in her set-up so…
In the past couple of weeks I’ve tried a few more molecules to flesh out the experimental verification of the separations model. This is a quick update of the results. In the following figure, the blue line is the predicted sieving curve, the green line sieving given a no membrane/free diffusion situation, and the blue…
One of the things that I’ve been working on recently is trying to explain the extreme elasticity of the pnc-Si material which is connected to its nanocrystalline structure. There are two parts in this question. First, how are amorphous or crystalline phases involved during stretching? Second, does the crystalline phase change under application of mechanical…
One of the features of the gold nanoparticle separations in SepCons that was under-appreciated by the reviewers at Science was the fact that we could get very high sieving coefficients in the neighborhood of the cut-off. For 5nm gold the sieving coefficient was 0.8 (i.e. the filtrate was 80% as concentrated as the stock solution)…
The current method of testing water permeability through SepCons is to place a volume of water inside a SepCon and spin it inside a centrifuge. After a set period of time, the volume passed is collected. The “approximate” permeability can be calculated as: volume passed/(pressure*area*time of experiment) in units of uL/PSI/cm^2/min. The reason this is…
We have a high school student, Nikita, (from my Summer Nanotech class) who is volunteering in the lab. Jim and I have assigned him the project of exploring diffusion of very small molecules through porous and putatively nonporous membranes. Currently, we are focusing on hydrogen peroxide (H2O2 = 34Da) and detecting it with the Amplex…
In the last production cycle, there were several wafers annealed for longer than our standard 1 minute RTP soak time. Recall in my earlier post, I observed a significant change in pore morphology in a 30 nm thick silicon membrane annealed at 1050 C for 1 min/5 min. In this series of experiments, we observe…
In this experiment, I wanted to test how quickly vacuoles form in endothelial cells when cultured on pnc-Si transwells. Here I used 30nm SC502 RTP’ed samples with the pnc-Si side down. I seeded P9 bEnd3 cells at 50000 cells/cm2 on the pnc-Si side, allowed the cells to attach for 2 hours and then inverted the…
This is a draft of a figure I think I’d like to use in my upcoming paper about charge based separations (this paper will include the Bernhard data). I thought I’d post it here first to get some feedback. I’ll first discuss the figure and then outline the problems that I see. Panel a. shows…