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

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Pallavicini, Piersandro Diaz-fernandez, Yuri Antonio Milanese, Chiara Dacarro, Giacomo Vita, Francesco Falqui, Andrea Cabrini, Elisa Casu, Alberto
Description	Author Affiliation: Pallavicini P ( Dipartimento di Chimica, Università di Pavia, viale Taramelli, 12, 27100 Pavia, Italy. piersandro.pallavicini@unipv.it.)
Abstract	Small (d ∼ 8 nm) magnetite nanoparticles, $Fe_{3}O_{4}NP,$ are prepared and coated with mercaptopropyl trimethoxysilane (MPTS) to form $Fe_{3}O_{4}NP@MPTS.$ In the coating step controlled $MPTS/Fe_{3}O_{4}NP$ molar ratios are used, ranging from 1 to 7.8 × $10^{4}.$ The total quantity of MPTS per $Fe_{3}O_{4}NP$ is determined by SEM-EDS analysis and the average number of free, reactive –SH groups per $Fe_{3}O_{4}NP$ is calculated by a colorimetric method. At very low molar ratios MPTS forms a submonolayer on the $Fe_{3}O_{4}NP$ surface with all –SH free to react, while on increasing the $MPTS/Fe_{3}O_{4}NP$ molar ratio the $(CH_{3}O)_{3}Si–$ 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 $Fe_{3}O_{4}NP@MPTS$ showing the typical behaviour expected for a sample with a mono-modal size distribution of superparamagnetic nanoparticles. Interaction of $Fe_{3}O_{4}NP@MPTS$ with gold nanostars (GNS) was tested, using both $Fe_{3}O_{4}NP@MPTS$ 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 $Fe_{3}O_{4}NP@MPTS,$ the free thiols of such nanoparticles bind GNS decorating their surface, as shown by UV-Vis spectroscopy and TEM imaging.
ISSN	14779226
Issue Number	48
Journal	Dalton Trans.
Volume Number	44
e-ISSN	13645447
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2015-12-28
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Chemistry
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

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