video (this version is saved to the server. It’s smaller and blurrier) http://www.youtube.com/watch?v=2JZ8uTWhejs&feature=youtu.be (this version is private – it can only be accessed by people with the exact link – it’s high quality) I modified the bottom basket of a Sepcon…
Author: Karl Smith
Karl is the 'separations czar' for NRG. As a Biophysics Ph.D. Candidate, Karl has the responsibility of characterizing new membranes, modeling the unique physics of nanomembrane separations, and finding ways to apply pnc-Si technology to protein purification, nanofluidic transistors, and human hemodialysis. Karl graduated from Allegheny College in 2011 with a double major in English and Physics.
Permeability Graphs for BSA Separations with Variable-Active-Area Sepcons Show Flow is Independent of Fractional Active Area
What I had in my two previous posts described as permeability graphs were in fact total volume passed/ total time passed graphs: What I thought I saw was that cake layer formation was dependent on the filter geometry. There is…
A New Round of Separations Still Shows an Increase in Filtrate Flux Above Normalization for Larger Active Area Sepcons
Using methods pretty much identical to those outlined in Tuesday’s post, I was able to get very similar data for a different BSA concentration. Whereas Tuesday’s curves were all done with 1mg/mL BSA, this was done with 0.5mg/mL BSA. The first…
Posted in NRG
Barcikowski Particles Revisited
The following are TECAN spectrum of the filtrates (and a spectrum of unconjugated peptide) for a series of sequential separations performed on the Barcikowski peptide (CE12W) using 10, 20, and 30nm cutoff Sepcons performed last weekend. Note that all of…
Posted in NRG
"Phantom" Curves on the TECAN Mess with Reproducibility and Accuracy
At some point, when things settle down, I’ll create a page dedicated to the TECAN machine and document all of the troubleshooting and tricks I’ve learned so far. Before that happens I have another mystery to solve. Take a look…
A quick graph showing that a higher active area/inactive area ratio sees less pore blockage
These volume measures were conducted at 5.6 +/-0.2 PSI using the variable area sepcons with either a half slot, one slot, three slots, or the normal five slots. Note that the pressure was normalized via a pressure regulator, and…
Posted in NRG Tagged with: BSA, pressure, pressure setup, separation, streamline convergence?, TECAN, variable area
40nm Gold Passes Through 40 nm pnc-Si Sepcon Chips; 100nm Fluorospheres Do Not.
On Friday Josh and I assembled Sepcon chips with calculated porosity of ~6.5 %, and avg. pore diameter of ~40 nm into Sepcons. I was able to pass 40nm gold through the pores (we don’t have any gold larger than that). Note…
Posted in NRG
TECAN absorbance for 96-well plates is topping out even with pure buffer
EDIT: This problem was solved thanks to Tejas. It turns out that Falcon BD transparent 96 well plates absorb in the UV range, and are best used for bradford assays or anything that measures absorbance higher than the UV range.…
Using Mass Spec to Detect the Barcikowski Protein
This week I tried looking into several different ways of detecting the elusive Barcikowski Peptide. We discovered that Coomassie staining does not work, both because of the size of the peptide (it only works on proteins with a MW >…
Posted in NRG
Cytochrome C can pass through 10nm EA-treated Sepcons
Using the remaining 10nm EA-treated chips (all of the 15nm EA-treated and all of the PEG-lyated chips had either been used or broken) I was able to pass cytochrome C through Sepcons. As usual, yields were low (~8-12uL) but the…
Posted in NRG
