w565 is permeable to rhodamine. I tested two chips using 100uM rhodamine using a time step of .5 minutes. Click on pictures to see animations.
position (1,-1) – While trying to do this first sample, MATLAB crashed and I was forced to take the movie about 7 minutes after the start. There is also a bubble of air stuck in the channel. Diffusion is apparent over time.
position (3,-1) – Much faster diffusion with no apparent pinholes.
Introduction In response to recent requests by our reviewers, I am looking to address two main concerns: 1) How does a collagen gel backing affect leukocyte transmigration, and 2) How does shear influence leukocyte transmigration. While we believe these areas are rich in information and need a significant amount of focus to tackle, we do…
Dave and I tested 8 wafers (187, 189, 310, 316, 318, 325, 327, 329) from the last 3 runs and traces of copper can be found within all the wells. However, the amount and position of this contamination varies greatly, with the most particles being located near the top of the well, away from the…
The idea of adding a pulldown modification to our bacteria assay protocol came about after we started to believe that pore discovery was our rate limiting step of the transmission process, discussed here. Initially, it seemed to benefit our assay as it bumped our performance up significantly. Upon closer inspection we realized that we had…
I talked about this yesterday in lab meeting, but here is the data. Since the components of HBSS by themselves did not cause discoloration (HBSS components), I adjusted the concentrations of NaCl, KCl, glucose, Na2HPO4 and NaHCO3 to match that of DMEM. The control was a wafer in DMEM/F12 with 10% FBS. None of these…
This was the first try at using PES for protein separations by diffusion. 100kD cutoff Nanoseps were used to separate 10mM KCl and 100mM KCl standards. In both cases, the backside fluid was gone after 24hours. I don’t think evaporation was the problem; either the membrane sucked up the fluid or it was drawn up…
Introduction The invasion of Staphlyococcus aureus into the cracks of cortical bone leads to osteomyelitis, a devastating disease often resolved by amputation [1]. The μSiM platform has been used to study the genetic mechanisms of S. aureus invasion. The membrane pores mimic the network of cracks in bone, referred to as the osteocyte lacuno-canalicular network…
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Yipee! Doesn’t this mean we have material to work with again?
Jess is gone for the rest of the week. Dave what does this tell you about material availability to wrap up some of Tom’s work? How many good membranes? Do we have pore sizes yet?
I’m cautiously optimistic. The dye diffusion is a good sign. I have a TEM appointment at 10 am so we’ll have some images soon. If there are pores, we should be able to produce enough usable material to finish off Tom’s experiments. Look for a post later today…
In the second picture, why does the slit look so long, or possibly why does the first slit look so short? I think the whole wafer is 1×10 slits, right?
Has anyone done any actual size measurements on these samples? They will always be a little different than the designed size due to the through-wafer etch, so some simple optical measurements should be done on every wafer to confirm the membrane dimensions.