Hello everybody,
I try to link peptide sequences to AuNP. I have found literature in which mixed monolayers of PEG and peptides have already been described (Krpetić et al. 2013), but I am interested in approaches using other PEG derivatives.
My first question is under which conditions (e.g. reducing agents, pH, etc.) a coupling of SH-PEG to AuNP (via Au-thiol) is the most promising?
Would you suggest sequential or parallel binding of peptide and PEG?
Which functional group and length of the PEG molecule would be suitable to mix it with hydrophobic peptide sequences from 5 to 15 AA?
I hope someone is having experience with this approaches.
Thank You for your Support.
Dear Fabian,
As far as I remember, the usual way is to graft HS-PEG-COOH to nanoparticles, then activate its COOH group by, say, NHS/EDC, and then add your peptide; it will be linked via NH2 end.
Dear Andrei.
Thank You for sharing your experience.
I have read about this approach. Though, in our case we try to couple the peptide directly to the gold via thiol coupling in order to obtain a mixed monolayer of peptides and PEG molecules.
Dear Fabian
If you want to attach AuPN to peptide through thiol coupling, you can use oxidative disulfide bond formation using DMSO. The same approach is applicable for attachment of PEG in case of the presence of thiol group on PEG molecule. Otherwise as Andrei said you can use amide bond formation between NH2 group of peptide and COOH group of PEG using EDC/NHS for the next step. Check this:
"Disulfide bond formation in peptides by dimethyl sulfoxide. Scope and applications"
doi: 10.1021/ja00017a044
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