Issue 2, 2019

Characterization of mixed-ligand shells on gold nanoparticles by transition metal and supramolecular surface probes

Abstract

We report herein two methods to characterize the surface of mixed-ligand shell gold nanoparticles, which was explored with gold nanoparticles containing varying molar ratios of 3-mercaptopropionic acid (MPA) and 3-mercapto-1-propanesulfonate (MPS) or 11-mercaptoundecanoic acid (MUA) and triethylene glycol mono-11-mercaptoundecyl ether (TEG) in their ligand shell. Incubation of gold nanoparticles with a solution containing the transition metal cation Ni2+ allows the extraction of Ni2+ depending on the number of negatively charged surface groups and the reaction of surface carboxylic acid groups with an aminomethyladamantane derivative allows the extraction of the supramolecular host molecule cucurbit[7]uril (CB7) depending on the number of reactive surface groups. In both the methods, the remaining surface probes in the supernatant could be conveniently quantified in a homogeneous solution after a simple centrifugation step. An excellent linear correlation between the amount of Ni2+ extracted and the ligand density of MPA and MPS in MPA/MPS gold nanoparticles or MUA in MUA/TEG gold nanoparticles afforded a simple and reliable assay method to determine the number of negatively charged surface groups. The supramolecular CB7 assay enabled the determination of the accessible ligand density of reactive surface carboxylic acid groups and revealed a striking difference in the number of surface groups that can be reacted with MPA/MPS gold nanoparticles or MUA/TEG gold nanoparticles, which suggests a simple method to probe the surface structure of mixed monolayer gold nanoparticles.

Graphical abstract: Characterization of mixed-ligand shells on gold nanoparticles by transition metal and supramolecular surface probes

Supplementary files

Article information

Article type
Paper
Submitted
27 Jun 2018
Accepted
19 Oct 2018
First published
22 Oct 2018

Analyst, 2019,144, 579-586

Characterization of mixed-ligand shells on gold nanoparticles by transition metal and supramolecular surface probes

M. Nilam, M. Ahmed, M. A. Alnajjar and A. Hennig, Analyst, 2019, 144, 579 DOI: 10.1039/C8AN01181H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements