All separations are 30 nm (diameter) gold nanoparticles in a 56 nm pore setup, with other parameters as described in my last post. Y-axis scale bar is in meters, x-axis scale is meaningless (the simulation is 1-D, and the width…
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.
Sieving Model 2.0 Curves for Varying Gold Concentrations, Membrane Thicknesses, Salt Concentrations, and Applied Pressures
These curves were all generated using the following package of matlab functions and scripts: (Sieving copy – run Find_Sieving_Coefficient_boltzmann.m – it’s set up to generate concentration profiles right now). The program begins with a ‘standard separation’ that uses the following characteristics: Pore diameter:…
Posted in NRG
Latest Computer Model of Sieving Looks Terrific
After a great deal of debugging and thought, I’ve made a small breakthrough in the modeling of sieving behavior using MATLAB, Bill Deen’s electrostatic model of pore-particle interactions, and a boltzman distribution to model concentration polarization (previous blog posts: Part…
Posted in NRG
Silicon Nanomembranes for Efficient and Precise Macromolecule Separations (book chapter)
Sometime in September, the group received the following invitation to write a book chapter: We, John Rogers from the University of Illinois at Urbana-Champaign and Jong-Hyun Ahn from Yonsei University, are editing a book that will be published by Wiley-VCH…
Posted in NRG
Graphs of IgG, qDot, and water passage for conjugated qDot preparations for Life Tech
Here is a graphical summary of the separation experiments performed the week of November 6th. Raw excel data is spread over 5 files: 11.4.14 qdot separations (10^13, 10^12, 10^11 Forward separations) 11.5.14 high conc reverse and forward (10^14 dots and IgG…
Posted in NRG
SepCon® Video Protocol: Wetting the membrane
Below is a video protocol for wetting a sepcon device. There is no audio but amounts are detailed.
Posted in Protocols (Public)
A New Platform for Pressure-Driven Voltage-Gated Separations
I’ve been trying for some time to make chips that can dynamically change their surface charge. To this end I’ve made the following NFT chips, which have 12 nm of silver coated in 10 nm alumina: Note the Aluminum…
Posted in NRG
Surface-Charge-Dependent EO Pumping Behavior Persists (weakly) at Low Applied Voltages
In a previous post (link) I presented a video that showed that the voltage applied to a silver film changed the pumping behavior of a membrane. The key data is summarized by the following powerpoint slide: My most recent post (link –…
Posted in NRG
Electrical Characteristics of Silver/Alumina NFTs
Just before BMES I was finally able to electrically characterize my NFT chips. Previously, I had been trying to collected IV sweeps using the following circuit: The problem with this was that, as Jess discovered, the membranes have almost no…
Posted in NRG
Using Resistance Measurements to Ensure Al2O3 Film Integrity
Sarah recently attempted to build a prototype voltage-gated drug release mechanism using one of my standard nanofluidic transistors. When she turned on her circuit (pictured below), instead of getting voltage-dependent diffusion behavior, she instead saw electro-osmosis. We’ve been debating what…
Posted in NRG
