Here is a look at all our water permeability through nanomembranes to-date. There appears to be subtle trends showing increasing permeability with radial position (r – values) and a not-so-subtle trend showing decreasing flow with protein (cyt and albumin). Note…

Wafer 302 appears to have no pinholes and held up pretty well in the centrifuge, up to 5psi for many hours in a wet-wet format. Here are some quick numbers on flow rate over 2 hours, 3.3psi, including radial position:1x…

I derived the governing equation for the volume transfer from SepCon devices in the wet/wet (EQ) format. It is … where the equilibrium volume for the cup can be calculated apriori using the cross sectional areas of the cup and…

This is probably not of general interest, but for the sake of full disclosure, I have spent considerable time working with our wafer supplier (Virginia Seiconductor) to resolve some issues regarding the surface quality of their wafers. It would have…

After the w310 series being beautiful (few pinholes, reasonable strength, high yield), we have retreated somewhat with a return of the copper-related piholes. Here is an SEM image and EDX scan from the well wall: Here is a pic of…

SepCon EQ reaches Equilibrium in 2 1/2 hours!w310 (no pinholes)1x PBS (no protein)2 hours @ 1000rpm (3.3psi) -> 103 uL passage (56 uL/(min-cm2-psi) )2 1/2 hours @ 1500 rpm (5 psi) -> 204 uL passage (>74 uL/(min-cm2-psi) ) In the…

last week I ran some tests using a single 100K microcon filter; this week I preformed essentially the same tests but instead of testing one filter over the entire pressure range I used a new filter at each pressure. I…

Permeability data first:Wafer 310r = 4.3 units from centern = 32.0 mg/mL cytochrome C in 1x PBSmean permeability = 27-33 uL/(min-cm2-psi) *** corrected to account for (2) 115x2014um slits[The range is due to variations in measurement and total accounting for…

Jim’s post inspired me to think about wetting of nanochannels. We raised this question before – Do we wet the channel in our membrane when water is applied to only one side? My guess was yes because of our success…

The following contribution comes from Jan Hoh – a Professor of Physiology at Hopkins, an invited speaker to BME in December, and a potential future collaborator. Jan sent his thoughts on why it is impossible to get flow through our…