Trapping and Release of Citrate-Capped Gold Nanoparticles

Published: August 01, 2011


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


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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gold nanoparticles, electrostatic interactions, self-assembled monolayers
Created August 01, 2011, Updated February 19, 2017