On Wednesday we ran several separations using both the EA and PEG treated membranes. The treatment process had damaged many of the chips. Of the 10 treated 10nm PEG chips, 2 survived. Of the 10 treated 15nm PEG chips, 2 survived. Of the 10 treated 10nm EA chips 8 survived. Of the 10 treated…
In a previous post, we showed that both Cytochrome C and BSA at concentrations of ~1mg/mL through 20nm cutoff Sepcons with about the same filtrate concentration (~60% of the feed concentration). Yesterday (1/14/13) we repeated these experiments with 10 and 15nm cutoff Sepcons and demonstrated pretty clearly that either 10 or 15nm Sepcons can be used…
Before the fresh Cytochrome C arrived, I ran two samples. The first sample was our old Cytochrome C in 0.3mM sodium phosphate buffer at a concentration of ~1mg/mL. I passed it through the 20nm cutoff 3rd generation Sepcons by spinning it in the small centrifuge at 2000rpm for 5 minutes. Approximately 100uL of sample passed through…
Recall that we’ve been having a great deal of trouble following the free ligand during our separations of the Bioconjugated Barcikowski particles, and that this trouble also means we can’t see the ligand after centrifuging the pure sample. In the interest of thoroughness, I replicated the assay the Barcikowski lab used to quantify the unbound…
On Friday(which was a great day for science). I ran a series of 5 passes of the bioconjugated gold nanoparticles through 30nm cutoff Gen 3 Sepcons. If you’ll remember, the Barcikowski lab wants the free ligand separated out from the complexes. To indirectly get the relative concentrations of gold and ligand, we measured the absorbance…
Nanoparticles Inventory – taken by Karl on 11/2/12. All these particles can be found in the refrigerator. Manufacturer size type amount (approx) expiration date fluorescence (if applicable) BBI 5nm gold colloid 3mL Jan-10 BBI 5nm gold colloid 6mL Aug-11 BBI 10nm gold colloid 2mL Jun-11 BBI 10nm gold colloid 2mL May-09 BBI 15nm gold colloid…
The Barcikowski lab sent us generous amounts of three different samples – gold, platinum, and bioconjugated gold. Each of the samples was created via laser ablation, resulting in fairly polydisperse (4-50nm diameter) nanoparticles for the pure metal and significantly less polydisperse (2-20nm, not including bound ligand) nanoparticles in the case of bioconjugated gold. As before,…
With Joe’s help, I was able to take some SEM images of the samples that I performed my previous set of separation experiments on. Sample 1: The obvious aggregation in this sample (exemplified by the ‘victory eagle’ blot in the second image) is observed in all five of the samples. What we can’t know is…
Because the Barcikowski lab intends to use the nanoparticles they sent us, relatively high yields are necessary for any step that cleans them up. This is unfortunate, because in every single separation that we’ve done (with one exception mentioned further on) we never see yields higher than about 5%. We’d thought that the problem was…
The Barcikowski samples, sent from Germany a month ago, continue to be a fecund source of inconsistant data. Using the DLS to monitor several filtrations has resulted in a series of baffling results that I think I’ve finally begun to understand. First, the promising results: A DLS of Sample 1 (a mixture of bioconjugated gold…