Fluorescence and interactions with thiol compounds of Nile Red-adsorbed gold nanoparticles
Resource
Journal of Colloid and Interface Science 307 (2): 340-348
Journal
Journal of Colloid and Interface Science
Journal Volume
307
Journal Issue
2
Pages
340-348
Date Issued
2007
Author(s)
Abstract
We have investigated the interactions between a variety of thiols and Nile Red-adsorbed gold nanoparticles (NRAuNPs). After adding thiols to solutions of NRAuNPs, the solutions fluoresce strongly as a result of the displacement of a Nile Red-derived product from the surface of the AuNPs. We propose a mechanism for the formation of this NR product on the surface of AuNPs by conducting mass spectrometry, fluorescence, and capillary electrophoresis measurements. By recording the fluorescence changes of the NRAuNP solutions after addition of the thiols, we investigated the interactions between the thiols and NRAuNPs. Using the Langmuir isotherm model, we found that the displacement rate constants for thiols having one carboxyl residue, such as 3-mercaptopropionic acid, fall within the range 0.55 - 1.19 × 10-2 s-1. Thiols containing hydroxyl groups [e.g., 2-mercaptoethanol (2-ME)] or amino groups [e.g., N-(2-mercaptopropionyl)glycine (MPG)], or that have flat structures on the AuNP surface, such as mercaptosuccinic acid, exhibit double-exponential kinetics with first rate constants of 0.51 - 2.83 × 10-2 s-1 and second rate constants of 6.0 - 23.4 × 10-4 s-1. Our results reveal that steric effects and the charge density of the thiols both play important roles in determining the interactions with NRAuNPs. The interactions (displacement and/or induced aggregation) are also dependent on the size of NRAuNPs. © 2006 Elsevier Inc. All rights reserved.
SDGs
Type
journal article
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
27.pdf
Size
303.21 KB
Format
Adobe PDF
Checksum
(MD5):96434d9d9ed04a892d7805d0b7480ae9
Loading...
Name
74.pdf
Size
473.14 KB
Format
Adobe PDF
Checksum
(MD5):a845f471bd9cf36e1cd965d9b55be9e7