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 is added just for clarity’s sake). The membrane is at y = 0. Color corresponds…
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: 58 nm Particle diameter: increases from 20 nm to 56 nm in 2 nm increments…
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 1 Part 2 Part 3). I had made a small conceptual error while generating the algorithm…
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 in 2015 on “Silicon Nanomembranes: Fundamental Science and Applications”. We would like to kindly invite…
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 combination forward and reverse separations) 11.10.14 (retentate numbers for all separations) summarized qDot data (summary and graphs)…
Below is a video protocol for wetting a sepcon device. There is no audio but amounts are detailed.
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 foil coating the insides of the gel box. The silver layer is either photoactive or…
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 – electrical characteristics…) showed, however, that the breakdown voltage of these silver and alumina NFTs is…
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 electrical resistance in this configuration, and I was essentially shorting out the circuit. This meant…
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 this means, but I contend that this means the insulating alumina film coating the silver…