Dear all, the best way in this situation is to use an anti-solvent precipitation. My Regards

https://doi.org/10.1016/j.tifs.2013.10.002

Do you want to spin down the nanoparticles by centrifugation? Because precipitation is related to solubility (and can be induced by modifying the solvent composition), I am not sure if this is what you want for your nanoparticles.

In order to wash/purify the polymeric nanoparticles (~200 nm in diameter), we spin them at 15000 rpm for 35 min. For smaller particles or those with smaller density, ultracentrifugation, spin filtration, or dialysis would work the best.

Good luck!

Yes thank's a lot , but the volume of my solution is very large and l want to collect nanoparticle powder from a volume of 300 mL!!!! High centrifuge seems to be hard for large volume....

Dear all, the best way in this situation is to use an anti-solvent precipitation. My Regards

https://doi.org/10.1016/j.tifs.2013.10.002

What size are the NPs? In my experience, 100-150 nm polydopamine NPs can be separated by centrifugation @ 20,000 x g for 40 min with repeated washing. If yours are smaller, I recommend ultrafiltraion or dialysis.

Hi;

Usually the formation of polydopamine is accompanied by a change in color of the solution from colorless to pale yellow and then to brownish black over time. The particles can then be sedimented by centrifugation at 15,000 rpm for 15 minutes. It is also possible to obtain polydopamine nanoparticles by precipitation with acetone. The latter is a co-solvent that you can add to your solution to flocculate the polydopamine nanoparticles. For more information please consult the following document.

With my best regards

Dear Aila Piri Mia, if you have not yet done it, you could try salting out method, which is used in some cases for protein purification. E.g. you can try to add some portion of Na2SO4 or (NH4)2SO4 or other salt(it depends) to your dispersions.

Yes, prof.Pud we use salting method and saw precipitate just in low concentration of polydopamin not high concentration!!!!! Do you know why??????