Hi,
I am looking at zeta potential values generated by Omni brookhaven instrument for lipid nanoparticles with siRNA at 10mM citrate buffer at pH range from 6.9 all the way to 2.5. I noticed that although the lipid nanoparticles contain cationic lipid which should be protonated at low pH and give positive values of the zeta potential, the opposite is being observed. This guy did something to the extracted data sort of converting the negative values into positive through some sort of normalization. Can this be done and if yes, how?
Thanks,
Aula
Short answer: No
Longer answer: I invented PALS (the technique used in the Omni. I helped Brookhaven develop the ZetaPALS) and I can't image any situation where you can take data of one sign and correct/normalize it to get the opposite sign. The only thing I can imagine is if you measure some other particles without the cationic lipid and compare the two. Even then without knowing how the surfactant is partitioned, attempting any correction is extremely subject to error.
I know (from a reliable source) that they sometimes have seen results with the opposite sign than expected. They don't know why - I do :) - but there's nothing they can do about it with their design. I can look at the raw data to see if it is the problem but it is too much to do via RG. I'm happy for you to contact me if you like.
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