Dynamic nuclear polarization of spherical nanoparticles

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dc.contributor.authorAkbey, Ümit
dc.contributor.authorAltin, Burcu
dc.contributor.authorLinden, Arne
dc.contributor.authorÖzçelik, Serdar
dc.contributor.authorGradzielski, Michael
dc.contributor.authorOschkinat, Hartmut
dc.date.accessioned2016-06-24T05:35:12Z
dc.date.available2016-06-24T05:35:12Z
dc.date.issued2013
dc.descriptionDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.de
dc.descriptionThis publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.en
dc.description.abstractSpherical silica nanoparticles of various particle sizes (∼10 to 100 nm), produced by a modified Stoeber method employing amino acids as catalysts, are investigated using Dynamic Nuclear Polarization (DNP) enhanced Nuclear Magnetic Resonance (NMR) spectroscopy. This study includes ultra-sensitive detection of surface-bound amino acids and their supramolecular organization in trace amounts, exploiting the increase in NMR sensitivity of up to three orders of magnitude via DNP. Moreover, the nature of the silicon nuclei on the surface and the bulk silicon nuclei in the core (sub-surface) is characterized at atomic resolution. Thereby, we obtain unique insights into the surface chemistry of these nanoparticles, which might result in improving their rational design as required for promising applications, e.g. as catalysts or imaging contrast agents. The non-covalent binding of amino acids to surfaces was determined which shows that the amino acids not just function as catalysts but become incorporated into the nanoparticles during the formation process. As a result only three distinct Q-types of silica signals were observed from surface and core regions. We observed dramatic changes of DNP enhancements as a function of particle size, and very small particles (which suit in vivo applications better) were hyperpolarized with the best efficiency. Nearly one order of magnitude larger DNP enhancement was observed for nanoparticles with 13 nm size compared to particles with 100 nm size. We determined an approximate DNP penetration-depth (∼4.2 or ∼5.7 nm) for the polarization transfer from electrons to the nuclei of the spherical nanoparticles. Faster DNP polarization buildup was observed for larger nanoparticles. Efficient hyperpolarization of such nanoparticles, as achieved in this work, can be utilized in applications such as magnetic resonance imaging (MRI).en
dc.description.sponsorshipDFG, GRK 1524, Self-Assembled Soft-Matter Nanostructures at Interfacesen
dc.identifier.eissn1463-9076
dc.identifier.pmid24192797
dc.identifier.urihttps://depositonce.tu-berlin.de/handle/11303/5638
dc.identifier.urihttp://dx.doi.org/10.14279/depositonce-5258
dc.language.isoen
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.ddc540 Chemie und zugeordnete Wissenschaftende
dc.titleDynamic nuclear polarization of spherical nanoparticlesen
dc.typeArticleen
dc.type.versionpublishedVersionen
dcterms.bibliographicCitation.doi10.1039/c3cp53095g
dcterms.bibliographicCitation.issue47
dcterms.bibliographicCitation.journaltitlePhysical chemistry, chemical physicsen
dcterms.bibliographicCitation.originalpublishernameRoyal Society of Chemistryde
dcterms.bibliographicCitation.originalpublisherplaceCambridgede
dcterms.bibliographicCitation.pageend20716
dcterms.bibliographicCitation.pagestart20706
dcterms.bibliographicCitation.volume15
tub.accessrights.dnbdomain
tub.affiliationFak. 2 Mathematik und Naturwissenschaften::Inst. Chemiede
tub.affiliation.facultyFak. 2 Mathematik und Naturwissenschaftende
tub.affiliation.instituteInst. Chemiede
tub.publisher.universityorinstitutionTechnische Universität Berlin

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