Electrochemical evaluation of the grafting density of self-assembled monolayers of polyethylene glycol of different chain lengths formed by the grafting to approach under conditions close to the cloud point

Chávez, Miriam; Sánchez-Obrero, Guadalupe; Madueño, Rafael; Sevilla, José Manuel; Blázquez, Manuel; Pineda, Teresa

doi:10.1016/j.jelechem.2022.116294

Cited by 4 publications

(2 citation statements)

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“…In experiments on SAMs on planar gold surfaces, n -alkylthiols adsorbed on (111) and (100) single-crystal gold substrates were examined. The density of the thiols on the surface was limited by steric effects, as in our study, giving typical molecular footprints of 0.22 nm 2 . , This was confirmed by Chavez et al, who performed electrochemical measurements of thiolated polyethylene glycols on planar gold surfaces and found a molecular footprint of 0.29 to 0.44 nm 2 , increasing with the length of the polyethylene glycol chain . Wu et al discussed the influence of the ligand density as a function of the size of the nanoparticles.…”

Section: Resultssupporting

confidence: 88%

“…83,84 This was confirmed by Chavez et al, who performed electrochemical measurements of thiolated polyethylene glycols on planar gold surfaces and found a molecular footprint of 0.29 to 0.44 nm 2 , increasing with the length of the polyethylene glycol chain. 85 Wu et al discussed the influence of the ligand density as a function of the size of the nanoparticles. They investigated gold nanospheres with diameters from 1.2 to 25 nm that were functionalized with (mercaptohexadecyl)trimethylammonium bromide (MTAB).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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The Molecular Footprint of Peptides on the Surface of Ultrasmall Gold Nanoparticles (2 nm) Is Governed by Steric Demand

Wagner,

Prymak,

Schaller

et al. 2024

J. Phys. Chem. B

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Ultrasmall gold nanoparticles were functionalized with peptides of two to seven amino acids that contained one cysteine molecule as anchor via a thiol−gold bond and a number of alanine residues as nonbinding amino acid. The cysteine was located either in the center of the molecule or at the end (C-terminus). For comparison, gold nanoparticles were also functionalized with cysteine alone. The particles were characterized by UV spectroscopy, differential centrifugal sedimentation (DCS), highresolution transmission electron microscopy (HRTEM), and small-angle X-ray scattering (SAXS). This confirmed the uniform metal core (2 nm diameter). The hydrodynamic diameter was probed by 1 H-DOSY NMR spectroscopy and showed an increase in thickness of the hydrated peptide layer with increasing peptide size (up to 1.4 nm for heptapeptides; 0.20 nm per amino acid in the peptide). 1 H NMR spectroscopy of water-dispersed nanoparticles showed the integrity of the peptides and the effect of the metal core on the peptide. Notably, the NMR signals were very broad near the metal surface and became increasingly narrow in a distance. In particular, the methyl groups of alanine can be used as probe for the resolution of the NMR spectra. The number of peptide ligands on each nanoparticle was determined using quantitative 1 H NMR spectroscopy. It decreased with increasing peptide length from about 100 for a dipeptide to about 12 for a heptapeptide, resulting in an increase of the molecular footprint from about 0.1 to 1.1 nm 2 .

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Section: Resultssupporting

confidence: 88%