Jump to main content
Jump to site search

Issue 48, 2015
Previous Article Next Article

Silane-coated magnetic nanoparticles with surface thiol functions for conjugation with gold nanostars

Author affiliations

Abstract

Small (d ∼ 8 nm) magnetite nanoparticles, Fe3O4NP, are prepared and coated with mercaptopropyl trimethoxysilane (MPTS) to form Fe3O4NP@MPTS. In the coating step controlled MPTS/Fe3O4NP molar ratios are used, ranging from 1 to 7.8 × 104. The total quantity of MPTS per Fe3O4NP is determined by SEM-EDS analysis and the average number of free, reactive –SH groups per Fe3O4NP is calculated by a colorimetric method. At very low molar ratios MPTS forms a submonolayer on the Fe3O4NP surface with all –SH free to react, while on increasing the MPTS/Fe3O4NP molar ratio the (CH3O)3Si– groups of MPTS polymerize, forming a progressively thicker shell, in which only a small fraction of the –SH groups, positioned on the shell surface, is available for further reaction. The MPTS shell reduces the magnetic interactions occurring between the magnetite cores, lowering the occurrence and strength of collective magnetic states, with Fe3O4NP@MPTS showing the typical behaviour expected for a sample with a mono-modal size distribution of superparamagnetic nanoparticles. Interaction of Fe3O4NP@MPTS with gold nanostars (GNS) was tested, using both Fe3O4NP@MPTS with a MPTS submonolayer and with increasing shell thickness. Provided that a good balance is used between the number of available –SH and the overall size of Fe3O4NP@MPTS, the free thiols of such nanoparticles bind GNS decorating their surface, as shown by UV-Vis spectroscopy and TEM imaging.

Graphical abstract: Silane-coated magnetic nanoparticles with surface thiol functions for conjugation with gold nanostars

Back to tab navigation

Supplementary files

Article information


Submitted
23 Jul 2015
Accepted
10 Nov 2015
First published
10 Nov 2015

Dalton Trans., 2015,44, 21088-21098
Article type
Paper
Author version available

Silane-coated magnetic nanoparticles with surface thiol functions for conjugation with gold nanostars

P. Pallavicini, E. Cabrini, A. Casu, G. Dacarro, Y. Antonio Diaz-Fernandez, A. Falqui, C. Milanese and F. Vita, Dalton Trans., 2015, 44, 21088
DOI: 10.1039/C5DT02812D

Social activity

Search articles by author

Spotlight

Advertisements