The last of the larger windowless pnc-Si chips were sent to both Adarza and Dr. Shestopalov’s lab for functionalization. Adarza returned chips with PEG-1 and PEG-2 (different rounds of processing) with both 2 hours and 16 hour treatments. They also returned a set treated with an alcohol leaving group ,ethanolamine (EA). They did also supply…
One major problem that we faced with our current shear-free chemotaxis system is the lack of high image quality. Since the silicon-nitride (SiN )grid is 100 um away from the coverslip surface on which the cells migrate, the out-of-focused SiN grid blurs the image. This makes cell tracking much harder. An example of a movie…
To assess how shear-free our [ “shear-free” chemotaxis system] is, we tracked the motion of nanoparticles in the shear-free compartment as we input a known flow rate in the flow compartment. The nanoparticles we use are the 210 nm dragon green fluorescent beads. ==================================================================Following is a 6-min long movie of the nanoparticles flown at a flow…
Hi all, We have already showed in our earlier [ post ] that our shear-free chemotaxis system can indeed elicit chemotaxis, suggesting that we have successfully translated a gradient through the membrane to the shear-free side of the system where the cells reside. However, it is still nice to show via fluorescence how the translated gradient looks…
This is a continuation of earlier work showing 30-100-30 NSN x-sections where the Si layer thickness increases from ~92 nm before RTP to ~130 nm after RTP. Below are SEMs showing a ~50 nm thick a-Si film becoming a ~62 nm thick pnc-Si. (1000 C, 50 C/s, 60 s in susceptor, RTP after EDP etch) I…
Below are some SEM images of a burst 30-50-30 NSN membrane in a SEPCON pattern. Many similar chips failed at lower pressures, but this one survived to ~5-7 psi. (didn’t keep close track of the chips after they were burst, so I’m not sure which pressure this burst at, but it was within the 5-7…
Upper and lower gaskets used to make a counter flow device. The danger is that the enclosing pdms can easily flex into the membranes on the flat side of the chip. A hard plastic cover can be used to prevent accidental contact between the PDMS and membrane.
Chips of pnc-Si were funtionalized at Adarza. They returned four groups of chips. Ethanolamine, Amino PEG-1, Inactivated sLinker, and Amino PEG-2. These were all incubated with PBS and 5-mg/mL f-BSA (2:3) in a humid refrigerated dish. The samples were rinsed in PBS then DI water and dried with filtered compressed air. The measurements were taken…
In the previous posts, I have shown that nanopores can be formed in silicon film sandwiched by two silicon nitride films. This discovery shows silicon nitride as an alternative barrier layer in the stack geometry. In this post, I’ll discuss a hypothesis about the pore forming conditions. The hypothesis is that either silicon dioxide or…
Following my fabrication process from my previous post, here are the results from my flow test of BBB device v2.6: The difference in the quality of the electrodes is apparent from these images. The microscope slide electrode was difficult to spin coat, resulting in an uneven photoresist coating, and worse patterning. Etching in 12M HCl…