Enhanced Relaxometric Properties of MRI “Positive” Contrast Agents Confined in Three‐Dimensional Cubic Mesoporous Silica Nanoparticles
Mesoporous silica nanoparticles (MSNs) are of growing interest for the development of novel probes enabling efficient tracking of cells in vivo using magnetic resonance imaging (MRI). The incorporation of Gd3+ paramagnetic ions into highly porous MSNs is a powerful strategy to synthesize “positive” MRI contrast agents for more quantitative T1 ‐weighted MR imaging. Within this context, different strategies have been reported to integrate Gd chelates to 2D pore network MSNs. As an alternative, we report on the modulation of the pore network topology through the preparation of a 3D pore network hybrid GdSixOy MSN system. In this study, 2D GdSixOy‐MSNs with similar porosity and particle size were also prepared and the relaxometric performances of both materials, directly compared. Both syntheses lead to water‐dispersible MSNs suspensions (particle size < 200 nm), which were stable for at least 48h. 3D GdSixOy‐MSNs provided a significant increase in 1H longitudinal relaxivity (18.5 s−1mM−1; 4.6 times higher than Gd‐DTPA) and low r2/r1 ratios (1.56) compatible with the requirements of “positive” contrast agents for MRI. These results demonstrate the superiority of a 3D pore network to host paramagnetic atoms for MRI signal enhancement using T1 ‐weighted imaging. Such an approach minimizes the total amount of paramagnetic element per particle.
Document Type: Research Article
Affiliations: 1: Center for Functional Nanomaterials, Department of Chemistry and Graduate School of Nanoscience and Technology (WCU), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea 2: Centre Hospitalier Universitaire de Québec Axe Métabolisme, Santé Vasculaire et Rénale (AMSVR-CHUQ), Department of Mining, Metallurgy and Materials Engineering, Université Laval, G1V 0A6, Québec, Canada and Centre de Recherche, sur les Matériaux Avancés (CERMA), Université Laval, Canada, Fax: (+) 1 418 525 4372 3: Department of Chemistry, Université Laval, G1V0A6, Québec, Canada and Centre de Recherche sur les, Matériaux Avancés (CERMA), Université Laval, Canada, Fax: (+) 1 418 656 7916
Publication date: December 20, 2011