title: Predictable Heating and Positive MRI Contrast from a Mesoporous Silica-Coated Iron Oxide Nanoparticle.
abstract: Iron oxide nanoparticles have great potential as diagnostic and therapeutic agents in cancer and other diseases; however, biological aggregation severely limits their function in vivo. Aggregates can cause poor biodistribution, reduced heating capability, and can confound their visualization and quantification by magnetic resonance imaging (MRI). Herein, we demonstrate that the incorporation of a functionalized mesoporous silica shell can prevent aggregation and enable the practical use of high-heating, high-contrast iron oxide nanoparticles in vitro and in vivo. Unmodified and mesoporous silica-coated iron oxide nanoparticles were characterized in biologically relevant environments including phosphate buffered saline, simulated body fluid, whole mouse blood, lymph node carcinoma of prostate (LNCaP) cells, and after direct injection into LNCaP prostate cancer tumors in nude mice. Once coated, iron oxide nanoparticles maintained colloidal stability along with high heating and relaxivity behaviors (SARFe = 204 W/g Fe at 190 kHz and 20 kA/m and r1 = 6.9 mM(-1) s(-1) at 1.4 T). Colloidal stability and minimal nonspecific cell uptake allowed for effective heating in salt and agarose suspensions and strong signal enhancement in MR imaging in vivo. These results show that (1) aggregation can lower the heating and imaging performance of magnetic nanoparticles and (2) a coating of functionalized mesoporous silica can mitigate this issue, potentially improving clinical planning and practical use.
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Katie R
authors.initials: KR
authors.lastname: Hurley
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Hattie L
authors.initials: HL
authors.lastname: Ring
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Etheridge
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Klein
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Szlag
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Connie
authors.initials: C
authors.lastname: Chung
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Reineke
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Bischof
authors.affiliation: Department of Chemistry, ‡Center for Magnetic Resonance Research, §Department of Biomedical Engineering, ⊥Department of Mechanical Engineering, ¶Department of Physics, ∥Department of Radiology, and #Department of Urologic Surgery, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Christy L
authors.initials: CL
authors.lastname: Haynes
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006361:Heating / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008280:Magnetics / Q000379:methods; D008297:Male; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology; D012822:Silicon Dioxide / Q000737:chemistry*; D014018:Tissue Distribution / Q000502:physiology
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D012822:Silicon Dioxide
keywords: SWIFT MRI; aggregation; colloidal stability; magnetic fluid hyperthermia; magnetic nanoparticles; mesoporous silica nanoparticles