High colloidal stability of gold nanorods coated with a peptide-ethylene glycol: Analysis by cyanide-mediated etching and nanoparticle tracking analysis



Free, P, Conger, G, Siji, W, Zhang, JB and Fernig, DG ORCID: 0000-0003-4875-4293
(2016) High colloidal stability of gold nanorods coated with a peptide-ethylene glycol: Analysis by cyanide-mediated etching and nanoparticle tracking analysis. Colloids and Surfaces B: Biointerfaces, 146. 871 - 878.

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Abstract

The stability of gold nanorods was assessed following coating with various charged or uncharged ligands, mostly peptides. Highly stable monodispersed gold nanorods were obtained by coating CTAB-stabilized gold nanorods with a pentapeptide with C-terminal ethylene glycol units (peptide-EG). UV-vis spectroscopy of these nanorods suspended in saline solutions indicated no signs of aggregation, and they were easily purified using size-exclusion chromatography. A more stringent measure of nanorod stability involved observing changes in the UV-vis absorbance of gold nanorods subjected to etching with cyanide. The max absorbance of peptide-EG coated nanorods red-shifted in etchant solution. The hypothesis that changes in the nanorod aspect ratio led to this red-shift was confirmed by TEM analysis, which showed pit formation along the transverse axis. The etching process was followed in solution using nanoparticle tracking analysis. The red-shift was shown to occur while the particles remained mono-dispersed, and so was not due to aggregation. Adding both etchant solution and peptide-EG to the nanorods was further shown to allow modulation of the max red-shift and increase the etchant resistance of peptide-EG nanorods. Thus, very stable gold nanorods can be produced using the peptide-EG coating approach and their optical properties modulated with etchant.

Item Type: Article
Uncontrolled Keywords: Gold nanorods, Colloidal stability, Peptides, Sodium cyanide, Nanoparticle tracking analysis, Etching, Red-shift
Depositing User: Symplectic Admin
Date Deposited: 07 Jul 2016 09:45
Last Modified: 16 Sep 2022 07:31
DOI: 10.1016/j.colsurfb.2016.07.006
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3002148