Predictable heating and positive MRI contrast from a mesoporous silica-coated iron oxide nanoparticle

Katie R. Hurley, Hattie L. Ring, Michael Etheridge, Jinjin Zhang, Zhe Gao, Qi Shao, Nathan D. Klein, Victoria M. Szlag, Connie Chung, Theresa M. Reineke, Michael Garwood, John C. Bischof, Christy L. Haynes

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)2172-2183
Number of pages12
JournalMolecular Pharmaceutics
Issue number7
StatePublished - Jul 5 2016

Bibliographical note

Funding Information:
This work was supported by the University of Minnesota (MN Futures, Institute for Engineering in Medicine Cancer Animal Core, and Institute for Engineering in Medicine Seed Grants), the NSF/CBET (1066343, 1336659, and 1133285), and the NIH (P41 EB015894 and R43HL123317). K.R.H. acknowledges support from an NSF Graduate Research Fellowship (00006595).

Publisher Copyright:
© 2016 American Chemical Society.


  • aggregation
  • colloidal stability
  • magnetic fluid hyperthermia
  • magnetic nanoparticles
  • mesoporous silica nanoparticles

MRSEC Support

  • Shared

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural


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