Retest-2: BSA and DDM diffusion with SC256 and 10mM salts

I made a post yesterday showing that in 20mM HEPES, pH7.5, +10mM NaCl solution equivalent amounts of DDM were diffusing through the “treated” and “untreated” SC256 samples. Additionally it appeared that minimal amounts of BSA were diffusing across either sample. I set up another diffusion experiment and let it sit overnight.

DDM analysis:

As observed in yeterdays diffusion experiment relatively equal amounts of DDM diffused across the “treated” and “untreated” SC256 samples. The final DDM filtrate concentration for the “untreated” SC256 sample was ~0.057% and the final DDM filtrate concentration for the “treated” SC256 sample was ~0.052%.

BSA Analysis:

After analyzing the results from the most recent diffusion experiment it appears that relatively similar amounts of BSA diffuse across the “treated” and “untreated” SC256 samples. The final BSA filtrate concentration for the “untreated” SC256 sample was ~0.57mg/mL and the final BSA filtrate concentration for the “treated” SC256 sample was ~0.54mg/mL.

Looking back on the past two diffusion experiments I set up using SC256 samples in 10mM salt solutions it appears that in both the amount of BSA diffusion is similar for both the “untreated” and “treated” cases. The introduction of salts into solution appears to be limiting the charge effect that was previously giving us a “separation” between the “treated” and “untreated” cases. I would expect that as the salt concentration increases this effect would become more and more apparent.