I set up diffusion experiments using the wafers that Tom was able to pass gold through in DI H2O using pressure. 5nm particles do not pass in 24 or 48 hours. If we have extra samples I will be testing 5nm particles in 10mM KCl.
This is a reprisal of the old post. While manufacturer declares particles to be 5, 10, etc, they do however give a measured average to their particles in the written material they provide. I did not have that in the last chart. Here I also add the standard deviation of TEM and Malvern data (as…
Originally, I created the following figure to visualize the relationship between sieving coefficient and molecular weight: (originally from this post) I can now take the protein dimensions that I obtained from crystal structures (posted here) and replot this figure: In this version of the figure the sigmoidal shape of the curve is even more obvious…
This post shows that C-dots are pretty close to neutral. Here I’ve looked at gold nanoparticles and albumin. 5nm Gold: The distribution is very spread out, but everything centers around -58 mV. 10nm Gold: This sample looks a little bimodal. Peaks are at -33 and 0 mV. Albumin: Much better than the gold samples. It…
I’ve tried to collect some information on the protein ladder that we’ve been using for separations. Sizes have thus far been taken from crystal structures and loosely measured used JMol on the PDB site. This is meant to just give us an idea of dimensions; hydrodynamic data would probably be better. pI and charge information…
I used 100kD Millipore Celllulose membranes to separate the 2 C-dot particles. The results are similar to those I’ve obtained with pnc-Si; the 10nm particles pass while the 30nm ones do not. Cy5 10nm particles: Sulforhodamine 30nm particles: Here are the sieving ratios: Particle Ratio 10nm (abs) .60 10nm (fluor) .59 30nm (abs) .02 30nm…
This post outlines two sets of polymer membrane separations using 100kD PES and 30kD cellulose in diffusion mode. The 100kD PES experiment is a repeat of the experiment found here; in the first trial of this work, there was no filtrate remaining on the backside. This time there was filtrate remaining that I could test…
I performed separations using C-dots from Hybrid Silica, a silica based particle with an internal fluorescent core. The particles are coated with a PEG layer of unknown length, but the idea would be that they’d be less affected by electrostatics than gold. I used two sizes. One is marked <10 the other <30, but I…
I have observed that in some cases the rate of EO can go up or down over the course of an experiment. Often the initial burst in the first 5 minutes is high, then the rate may stabilize or drop. I have observed that the rate of EO seems closely related to the current. Here…
This is a short review of a few experiments that Tom had set up this morning. Carbonized membranes: A few carbonized membranes that were used for permeability measurements were tested in EO. The membranes were left in the sepcon, which was filled and placed in a reservoir. Electrodes went inside the sepcon and the reservoir. …