Background Details: Josh Miller & I have made some recent progress in the NPN LO work. We had several ø6″ wafers w/ 100 nm of thermal oxide processed by Rogue Valley, wherein they deposited 650 nm of poly-Si (LP-CDV) followed by 50 nm of low-stress SiN (LP-CVD). Josh added the a-Si + SiO2 layers at…
These fits are done using the math outlined in this previous post. We assume an average pore size of 50 nm and an approximate number of pores in the membrane of 1E9. 20 nm particles: 100 nm particles: Next, we were curious whether we could show the transition happen from pore constriction to…
I was not entirely satisfied with the amount of data that I received from my last burst pressure wafer, so I processed another wafer. This wafer had some yield loss initially, as well as window sizes that were slightly smaller than expected (by about 50 microns). We expect the mechanical strength of the windows to…
In my previous post, I derived a formula for the time-dependent flux decline in a centrifuge-driven membrane separation, assuming that the resistance of the membrane was held constant. The problem with that approach is that, as Josh discusses in this post, the resistance of the membrane increases with time according to one of several standard…
Kevin Healy is a Phase I and Phase II awardee of the NIH Tissue Chip initiative. The goal of this initiative is to create ‘mini-organs’ ‘organs-on-a-chip’ ’tissue chips’ or ‘microphysiological systems’ (MPS) for higher throughput and more reliable drug discovery. The effort is also motivated by the failure of recent animal models to predict drug…
I was given three groups of chips to SEM. The first group had undergone the Diazerine and PEG1000 treatment followed by incubation with either PBS, IgG, or BSA. The second ‘group’ was a chip that had been treated with diazerine and PEG1000 but had not been incubated. The last group was a chip which had…
In my recent tenting posts, the membrane has shown that it can deform and wrap around edges. I wanted to follow up on this phenomenon and see if we could get a contiguous sheet of membrane around a PDMS edge (not completely sharp). If we can get some membranes around a ~90 sidewall, we could have…
In Josh’s forthcoming paper about clogging in forward and reverse configurations using 20 nm and 100 nm sepcons, we thought there was reason to discuss how the data agrees with the already existing models of membrane fouling. In this post, Josh discusses some of his efforts to model the data without accounting for the fact…
This is a followup to my previous post, which can be found here. Previously I reported that fluorescein diphosphate (FDP) incubated on the surface of an NPN chip would adhere well enough to be visible on the membrane after gentle washing and treatment with a fluorescence-activating enzyme (alkaline phosphatase, AP.) I also reported that pre-incubation…
It is of interest to investigate the properties of CO2 transfer into a cell culture media using nanomembrane technologies. Maintaining the pH of the cell culture medium is critical to cell viability. Most cell lines grow well at pH 7.4 and are inhibited by growth at pH 6.8. Glucose is usually the sugar included in…