Peptide functionalized gold nanoparticles: the influence of pH on binding efficiency

D Dixon, Jeremy Hamilton, Emma Harrison, Manuel Macias-Montero

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


We report herein on the synthesis of mixed monolayer gold nanoparticles (AuNPs) capped with both polyethylene glycol (PEG) and one of three peptides. Either a receptor-mediated endocytosis peptide, an endosomal escape pathway (H5WYG) peptide or the Nrp-1 targeting RGD peptide (CRGDK) labeled with FITC. All three peptides have a thiol containing cysteine residue which can be used to bind the peptides to the AuNPs. In order to investigate the influence of pH on peptide attachment, PEGylated AuNPs were centrifuged, the supernatant removed, and the nanoparticles were then re-suspended in a range of pH buffer solutions above, below and at the respective isoelectric points of the peptides before co-functionalization. Peptide attachment was investigated using dynamic light scattering, Ultra-violet visible spectroscopy (UV/Vis), FTIR and photo luminescence spectroscopy. UV/Vis analysis coupled with protein assay results and photoluminescence of the FITC tagged RGD peptide concluded that a pH of ∼8 optimized the cysteine binding and stability, irrespective of the peptide used.
Original languageEnglish
Article number295602
Number of pages11
Issue number29
Early online date28 Jun 2017
Publication statusPublished online - 28 Jun 2017


  • gold nanoparticles
  • PEG
  • pH
  • isoelectric point
  • peptide
  • attachment
  • functionalization


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