“I’ve looked at clouds from both sides now” is a Joni Mitchell song. Some Background We are developing a white blood cell (WBC) detector to surveil peritoneal dialysate fluid during fluid exchanges for early detection of peritonitis. This preemptive monitoring is currently not available in clinical practice. The current detection method is by visual inspection…
I drew an approximation of the SiMPore liftoff device and ran the COMSOL model with 1 mL/min urea fluid flow in the upper channels and 2 mL/min dialysate in the bottom channels. With this initial model, the urea was cleared to 40% (60% removed). This is an instantaneous urea clearance rate of K= 0.6 mL/min….
We’ve calculated our instantaneous clearance numbers for the benchtop studies that use sepcon chips. Even calculating per unit area, our chips are not clearing much volume in these experiments. I believe this is due to the very low flow rate (1 µL/min). Kayli is starting experiments to use higher flow rates with the same chips…
In 5.4 mm single slot chips, sheep blood was flowed at 3 µL/min though the 3 mm x 1 mm channels with PBS flowed at the same rate but in the opposite direction for four hours. The chips were pre-wetted with PBS and rinsed following flow. The membrane surfaces were fixed with 4% paraformaldehyde for…
The purpose of this study will be to compare the cellular adhesion on PEG vs Bare nano porous silicon nitride membranes using the same fluidic devices as the in vitro clearance study. The devices will need to be disassembled for imaging. Materials: 6 chips, 3 PEGylated, 3 Bare. gaskets for 6 devices Tygon tubing 2…
I recently attended ASN’s Kidney Week 2017 in New Orleans. I mostly ate beans and rice, although there are three completely vegan restaurants and several restaurants with vegan options. The music was terrific and the weather was terrific, the people were terrific, etc. I had Five objectives for my trip to this conference. 1. Meet…
I created a COMSOL model (zip) model with geometry based on the CAD drawing of the sepcon fixture Jared provided. I’ve included Velocity results (then Concentration, Pressure, Vorticity, and Shear rate). Also included is the Parameter table which has the Diffusion Coefficient for Urea taking into account the drawn thickness of the membrane (100 µm) vs…
Another set of images of both sides of a membrane, this time something weird is happening… It looks as though I’m missing some holes from the top side. They looked to be filled in but are not when seen from the back. Here is the backside of the wafer showing a bunch of holes. (the…
While JK has been processing backside images from 50 nm, 75 nm, and 100 nm membrane SEM images for pore information, I thought I’d take a look at a 100 nm membrane from both the front and the back at the same spot. Here are the images referenced to a corner of the trench. The…
Here is a better, more thoughtful, attempt at pore processing of a single image of the backside of a 75-nm thick membrane (four slot). One thing you will note that could be different from the analysis of the frontside of the membranes: The small openings that appear quite sharply defined here could be missing from the frontside…