As discussed in a previous post, we decided to test chips from wafer #1070 because they have smaller pores than those used in the most recent forward vs. reverse study. In the forward direction, 31 uL of filtrate was passed after 30 minutes at 3 krpm. (after 30 additional minutes at 5 krpm the total…
Scott Russell from Mech. E. and Steve Gillmer came over to help Sarah and I try to record the burst of membranes at up to 2000 frames per second. Generally we used 100o frames per second because it was the best compromise between our ability to time the 1 s recording time and the amount…
We had previously tested different surfactants to see if we could get 20 nm polystyrene beads and IgG to stay in suspension while filtering with the centrifuge. We found 0.1% Tween 20 to be sufficient when dealing with 10:1 (5×10^14) 20 nm NPs and 1mg/ml IgG. During the reverse centrifuge studies we mixed 10^15 particles/ml…
We have previously tested the effects on filtrate volume after a given time as a function of concentration. Moving forward we want to quantify the improvement in filtrate volume when using reverse centrifugation instead of forward centrifugation. Initially, we attempted to create similar plots to those in the preceding post but got the following gobbledeegook:…
I went over to RIT to work with JP on measuring the deflection of NPN and pnc-Si membranes as a function of pressure. JP and Dave Fang did this work years ago, and we want to pick it up again to correlate with Sarah’s burst pressure data. We used the Veeco Wyko (white light interferometer)…
We are carrying out filtrations using wafer 1085. We are testing the total volume of filtrate that passes in a given time. We expect the total filtrate volume to decrease as concentration increases due to more immediate clogging. Ultimately, we want to show that we can get higher total volumes of filtrate in the reverse…
Below are various SEMs of NPN membranes. (All samples were coated with metal by using the Denton Ag sputterer for 120 s) These were used samples that have been sitting out in the lab for weeks. I don’t remember the exact details of the processing. I believe they were filters we used to test the possibility…
Yaron has acquired an Omega rotameter (FL-3803ST) with interchangeable flow tubes. The tubes operate in three different ranges low (6-61 mL/min, 042-15-N), medium (150-1,682 mL/min, 082-03-N), and High (1,000-23,752 mL/min, 034-39-N). I’ve attached an excel file with the calibration data plotted. We fit the curves with polynomial trendline to get equations. Also in the workbook…
Our previous work with reverse centrifugation NPN membranes has shown that they may work for cleaning up excess protein from conjugated NPs. This initial success used ~20 nm red fluospheres with membranes from wafer 1070 (10-15%, ~45nm) and unlabeled IgG we were given by a collaborator. In this post we are testing “newer” NPN wafers…
Mary Lee and I performed a quick test to determine the efficacy of different surfactants at reducing agglomeration between IgG and 20 nm fluospheres. Each solution is a combination of 50 uL 10 mg/mL IgG (in PBS) + 50 uL 20 nm red Invitrogen fluospheres + 500 uL of surfactant. We used 1 x PBS…