In this post, pores from four different structures are compared. Those four different structures are nitride/silicon/nitride (NSN), nitride/silicon/oxide (NSO) , oxide/silicon/nitride (OSN) and oxide/silicon/oxide (OSO) . The thicknesses of nitride, oxide and silicon are 30nm, 30nm and 25nm, respectively. Wafers with four different structures were etched first to remove the substrate. The four different free…
It was speculated that the rate of diffusion through a charged membrane had a direct relationship with pressure – as pressure increases, the kinetic energy of the charged particles is more likely to overcome the electrostatic repulsion of the membrane, until at a high enough pressure the repulsive force is small enough to be ignored….
Hi all! Last time we have presented a theoretical perspective on the shear stress reduction enabled by our shear-free microfluidic system. This time we will show an agreement between the shear-reduction predictions made by the analytical solution and a COMSOL simulation. For details on the analytical solution please refer to the following post: [https://trace-bmps.org/datablog/2012/04/26/shear-stress-reduction-via-pnc-si-analytical-solution/] COMSOL…
Hello everyone, presented here is a theoretical perspective on the shear stress reduction enabled by our shear-free microfluidic system. Briefly speaking, the shear-free microfluidic system consists of three main components: a flow compartment, the pnc-Si membrane, and a shear-free compartment. The membrane attenuates the fluid flow from the flow compartment to the shear-free compartment while permits…
In order to rapidly test the entire setup for dialysis evaluation, including piezoelectric micro motor and recirculating fluid path, a means of quickly evaluating PDMS designs is needed. A mold was created with a multi-print technique in which printer toner is built up to sufficient height by over printing the same transparency. (see Fig. 1)…
The goal of the blood brain barrier device is to co-culture cells in a closed system, with the apical chamber under flow conditions, while still being able to access either chamber for media changes or to introduce new solutions. Electrodes to measure TEER will need to be included in future design iterations. There are two…
One aspect of the blood brain barrier device is that it be a closed flow system. This would not only better mimic an in vivo environment, but also maintain Sema4D activity, negatively affecting endothelial cell junctions and providing a target for the antibody. The microporous membranes were not yet available, so a closed flow system…
A quick recap: Vaccinex has asked the lab to design a closed system device with the capability to co-culture on microporous membranes. This device would be used to mimic the blood brain barrier, with endothelial cells cultured on the apical side and glial cells cultured on the basal side, and would allow for the testing…
Over the last week or so I’ve taken some lovely SEM pictures with Joe, used the light scatter, and ran some separations on filters I assembled myself. Someone from the Barcikowski lab, Dr. Rehbock, got in touch with me and sent me an updated description of the four samples they’re sending and what they want…
Barrett had discovered that growing endothelial cells on pnc-si or tranwells causes vacuoles to form. The vacuoles on pnc-si formed only on the free standing areas of the membrane where there are open pores. The background on pnc-si chips showed negligible vacuole formation. The density of vacuoles on pnc-si was almost two fold higher than…