RTP Treated Membrane Stability in DMEM
(Transferred from old blog)
Wafer 303 samples, both non-RTP and RTP (800C for 5 minutes), were tested in cell media (DMEM supplemented with 10% FBS) or deionized water, and placed in the incubator (37C 5% CO2) or oven (approximately 37C). Discoloration, pH, and the bead assay were measured initially and every 24 hours. Deionized water and DMEM control samples not containing membranes were used as pH controls. The experiment has been going for 3 days and is ongoing.
Results:
As shown in the figure below, RTP and no RTP samples in the oven in DMEM discolored after 24 hours. 48 hours of incubation in the oven caused discoloration of deionized water samples to occur. In contrast, samples in the incubator, including all deionized water and RTP treated DMEM samples have shown no discoloration after 72 hours. Non-RTP treated samples began to discolor after 2 days. These results confirm Anant’s previous benchtop and incubator DMEM experiment and support protective nature of acidic conditions (incubator) in regards to membrane degradation.
The pH in sample wells was measured over time to see if the membrane and media are interacting in some way to change the pH. Thus far little variation in pH in wells containing RTP and non-RTP membranes from DMEM containing no membrane has been observed, with the pH of DMEM in the incubator hovering around 7.60 and in the oven around 9.5.
In conclusion membranes are more stable in acidic condition in the incubator where DMEM is buffered with carbon dioxide. Furthermore RTP treatment delays discoloration in both DMEM and water in the incubator.
Was this RTP in Ar or O2?
This RTP treatment was in Ar. This was also my first discoloration study (I hadn’t yet mastered the method) so the “drying spots” on the membranes for the first one to two time points should more or less be ignored.