Trapping and Release of Citrate-Capped Gold Nanoparticles

Published

August 1, 2011

Author(s)

Darwin R. Reyes-Hernandez, Geraldine I. Mijares, Brian J. Nablo, Kimberly A. Briggman, Michael Gaitan

Abstract

An electrical method to trap and release charged gold nanoparticles on and from the surface of alkanethiol self-assembled-monolayer (SAM) modified gold electrodes is presented. Gold nanoparticle (GNP) coated electrodes were formed by immersing amine-terminated SAM-modified gold electrodes into a solution of negatively-charged citrate-capped gold nanoparticles (GNPs). The electrostatic interactions kept the GNPs trapped on the electrode. The presence of the GNPs decreased the impedance of the SAM-modified electrode, and increased the electrochemical activity at at the electrode as shown through cyclic voltammetry. The application of a subsequent negative bias initiated a partial release of the gold nanoparticles. Impedance spectroscopy, cyclic voltammetry, UV-Vis spectrophotometry and AFM imaging were used to monitor the attraction and release of gold nanoparticles to and from the SAM-modified gold electrodes. This work describes a trapping and release method for citrate-capped gold nanoparticles that could find use in applications such as nanotoxicity studies and other microfluidic assays, and functionalization of gold nanoparticles.

Citation

Applied Surface Science

Volume

257

Issue

20

Pub Type

Journals

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Keywords

gold nanoparticles, electrostatic interactions, self-assembled monolayers

Citation

Reyes-Hernandez, D. , Mijares, G. , Nablo, B. , Briggman, K. and Gaitan, M. (2011), Trapping and Release of Citrate-Capped Gold Nanoparticles, Applied Surface Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904039 (Accessed October 11, 2025)