Multifunctional core-shell nanoparticles: superparamagnetic, mesoporous, and thermosensitive
2011 (English)In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 11, 6157-6167 p.Article in journal (Refereed) Published
Multifunctional core-shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe3O4 NP as the magnetic core, mesoporous silica (mSiO2) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO2-coated Fe3O4 NPs (Fe3O4@mSiO2) are monodisperse and the particle sizes were varied from 25 to 95Â nm by precisely controlling the thickness of mSiO2-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe3O4@mSiO2 NPs through free radical polymerization. These core-shell composite NPs (designated as Fe3O4@mSiO2@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r2 relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications, the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers to be around the human body temperature (i.e. 37Â Â°C), from ca. 34 to ca. 42Â Â°C. The thermal response of the core-shell composite NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled drug release, and temperature-programed magnetic targeting and separation applications.
Place, publisher, year, edition, pages
2011. Vol. 13, no 11, 6157-6167 p.
multifunctional, iron oxide, mesoporous silica, PNIPAAm, core-shell, LCST
IdentifiersURN: urn:nbn:se:kth:diva-35505DOI: 10.1007/s11051-011-0272-8ISI: 000297351600063ScopusID: 2-s2.0-84857035953OAI: oai:DiVA.org:kth-35505DiVA: diva2:428878
QC 20110701. QC 201202092011-07-012011-07-012012-06-05Bibliographically approved