Hi
Im functionalising gold nanoparticles with thiolated oligos. Part of all (Or all that Im aware) protocols require spinning the final solution down at 13,300 rpm for 20 minute cycles to seperate any remaining unattached oligos. It seems like large amounts of the gold aggregate in this method even after 1 spin cycle. When the final product is examined under atomic force microscope this seems to be confirmed as there are large aggregates in solution and no smaller structures visible.
Does anyone have any experience with this method or advice?