I recently set up 24 hour diffusion separations with the BioRad protein standards. The following gel shows the separations using w415 position (-4,3) and w416 (-1,3). Different cutoffs were observed with the two membranes.
Key Ideas I took a wafer with ~400 chips of varying square window sizes, ran my MgF2 process, and recorded the pressures it took to burst them. Overall yield was about 20%, most of them smaller windows. I was expecting ~50% based on my previous work. Variation in the etch step destroyed the yield. MgF2 nanomembranes…
We will devote the first NRG meeting of each month to journal club. First up is Karl who will review two papers describing the use of single nanopore membranes as a method of characterizing particle size and zeta potential on a particle by particle basis. The technology produces intriguing data sets like the one shown…
Lately I’ve been working on building computational models which can be used to make predictions about the behavior of a diffusion experiment, to allow for the collection of large pools of data without the difficulty and time consumption associated with actually performing an experiment. This could prove to be a valuable tool for the continued…
Manufacturer’s Data Logged by: Ahmet Gurcan Membrane Type: MSSN 1 micron Microslit SKU: MSSN400.C-3LX.1-1.0E2 Lot Number: 240913-25 Quantity Received: 340 Manufacturer Test Report: Flow Data Avg in SLPM 1psi: 1.67 2psi: 3.1 4psi: 5.19 15psi: 11.87 Burst: 39.9 PSI
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…
I have a preliminary result from Kevin that there is a layer of fluoropolymer remaining on my MgF2 freestanding nanomembranes (which could explain some of the carbon signal in EDX from my previous posts). This would create another unnecessary signal for the intended Raman spectroscopy application. Remembering an old graph from my schooling, I dropped…
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Looks pretty good. 1) Are there enough membranes to do this by convection? 2) We need to get pore size histograms to see if these make sense. Dave are you going to upload images to the TEM directoy?
We do not currently have enough membranes to study convection. We’ll have to put 2 wafers aside for me to do two cutoffs in both diffusion and flow modes.
I’ve taken images on Brian’s TEM (wafer 415, wafer 416), but the images have low contrast and the pore processing program can’t pick up the features. I’ve scheduled some time with Karen on Wednesday and will put pictures up along with statistics at that time.
Remind me about the protocol again. 1x PBS with 3uL on top, 40uL on the bottom, then the retentate is diluted to the volume of the filtrate?
These gels look very nice with relatively sharp cutoffs and depletion of the small proteins. Do we know what each of these are? Interestingly 415 has a cutoff near 50nm and 416 has cutoff of maybe 60nm, based on the posted images. I would have expected everything to just diffuse through such large pores…
2uL of sample in the well, 60uL of 1xPBS in reservoir. 58uL are added to the retentate.
We know all the proteins in this gel. The one not appearing in the retentate of the first gel is hen egg white lysozyme (HEWL).