David Paramelle’s paper on using gold nanoparticles stoichiometrically functionalised with a peptide that recognises sphingolipids has just been published in Advanced Healthcare Materials (Publisher’s site; Pubmed)
The paper is the classic “Sunday afternoon” project, which arose through discussions with Rachel Kraut at NTU.
As ever, a lot more than Sunday afternoons ended up being put into the paper, because David had to develop some new approaches. Particularly nice was the purification of nanoparticles functionalised with the sphingomyelin-binding peptide (called “SBD”) from non-functionalised nanoparticles. This is a key step for the preparation of nanoparticles carrying just one functional peptide or group. Hitherto, we have happily had affinity tags as the functional group, which allows for affinity chromatography (examples here, here and here).
With the SBD peptide there was no such opportunity, so David figured a way using ion-exchange. Specific purification by ion-exchange of nanoparticles carrying a charged function has often been difficult to implement on nanoparticles, perhaps because of interactions between the functional part of the ligand and the underlying ligand shell. However, in this case it worked very nicely. Result, nanoparticles functionalised with a single SBD peptide, able to recognise sphingolipid enriched membrane domains (lipid rafts), at a sensitivity far higher than fluorescently-labelled SBD peptide.