Last week, I looked at discoloration with different wafer numbers (639,670,672,683,685,702,703), pre- and post-rebuild.  This experiment was done in the oven at 37C, in PBS and without RTP.   Based on the starting color, w670 and w672 are the thinnest membranes.  These discolored rather quickly (1 day).  The only other membrane that discolored over 3…

I attempted a diffusion study with w685 three days ago. If you were following the comments on the w685 page, you’ll know I had some difficulty pipetting the protein solution into the well. I haven’t had this problem recently, and when I used to encounter this problem I would etch the remaining backside oxide with…

I guess there was a mistake in the last permeability plot.  The real data for the 4 bar plot should look like this: Unfortunately that doesn’t look so good anymore.  The third bar though is the one that I originally processed to have many more pores (w705).  The reprocessing gets it down in the 8%…

I’ve prepared a few slides of discoloration data for tomorrow.  The images didn’t copy over from the blog very well, but I think they are good enough for a discussion. labmeeting_oct211

More discoloration experiments.  No wafers were RTP’ed, and I looked at different wafer numbers.  For each experiment, I looked at discoloration in the oven at 37C and the incubator.  The labelling might be a bit confusing.  For the top right pictures, I looked at 4.4 mg/mL KHCO3 (left chip) and 0.35 mg/mL NaHCO3 (right chip)….

In my previous post, there still appears to be a discrepency between the calculated pore statistcis and the experimental permeabilities. I explored what I could do with the pore processing to bring the experimental closer to the calculated permeabilities. I set the minimum pore cutoff higher (15nm) and tried to remove any pores that did…

A couple weeks ago, I posted some pictures that showed a non-linear “dose-response” curve for NaHCO3 and discoloration in the incubator (post).  I repeated this experiment at 37C in the benchtop oven.   These pictures show that there was a NaHCO3 concentration dependence on the discoloration rate in the oven.  In the 2nd set of…

Bernhard Group: Discoloration was observed during DNA separation experiments.  Further study led to these results: No discoloration observed with low pH buffered NaCl. Discoloration with high pH buffered NaCl. Worried that Cl was the culprit, sodium acetate was tested.  Discoloration observed with sodium acetate. In one early experiment, 4 areas were tested on one chip. …

Since Jess saw discoloration last week within a day in PBS with the new material, I did a couple of discoloration studies this week.  I looked at wafers 670 and 673 and compared them to 625, 704 and 680-T.  These were not RTP’ed, I did the tests at RT since that’s the temp diffusion studies…

I got back on the AFM today to rescan the wafers from yesterday and too scan a wafer that Dave had given me a few weeks ago.  The 2 panels are from the height channel, I used the 240 tip (yesterday I used the 160 tip).  The top panel is the wafer from Dave and…