Diffusion through non-porous membranes figure
A couple weeks ago, I presented a potential figure for my paper that didn’t make sense. So, I did a couple more controls and put together this new figure. This is the “diffusion through ‘non-porous’ SC348/cut-off of nonporous membranes” figure. I redid it to include SC348 (the nonporous sample) and ‘typical’ pnc-Si as % of expected equilibrium concentration for 4 different molecules:
My thoughts:
Since each diffusion set up was different, the equilibrium concentrations between experimental molecules were totally different (as are the time courses), so comparing the y-axis values between molecules is not correct.
NaCl is significantly hindered in SC348 but not typical samples. This doesn’t make sense, unless there is a considerable charge effect with SC348.
H2O2 (34Da) gets through SC348 similarly to typical pnc-Si – makes sense since this is a tiny, uncharged molecule.
Cytochrome C (~12kDa) makes sense – not getting through SC348 but getting through typical samples (a size hindrance).
Fluorescein (330Da) isn’t getting through typical samples all that well but it is only slightly hindered in SC348. This experiment is above the pKa of fluorescein, so the deprotonated form of fluorescein may experience charge effects (a la NaCl). Therefore, SC348 is passing this small molecule similarly to typical samples.
So, if we argue that there is a potential charge effect, this figure says that small molecules (<300Da) pass through SC348 but larger molecules (somewhere between 0.3kDa and 12kDa) can not pass this sample.
I guess I’m looking for feedback about how this figure seems – too confusing, too cumbersome to explain, OK, etc?