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Updated: Oct 7, 2025
Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
Published on: December 9, 2010
Label-Free Iron Oxide Nanoparticles as Multimodal Contrast Agents in Cells Using Multi-Photon and Magnetic Resonance
Hendrik Reynders1, Indra Van Zundert1, Rui Silva1,2,3
1Molecular Imaging and Photonics, KU Leuven, Leuven, Belgium.
Introduction:
The inherent fluorescence properties of iron oxide nanoparticles (IONPs) were characterized, and their applicability for multiphoton imaging in cells was tested in combination with their magnetic resonance imaging (MRI) capabilities.
Methods:
Superparamagnetic iron oxide nanoparticles were synthesized and subsequently coated with polyethylene glycol to make them water-dispersible. Further characterization of the particles was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), superconducting quantum interference device (SQUID) and magnetic resonance relaxivity measurements. MRI and fluorescence properties of bare IONPs were first studied in solution and subsequently in A549-labeled cells.
Results:
The particles, with a core size of 11.3 ± 4.5 nm, showed a good negative MRI contrast in tissue-mimicking phantoms. In vitro studies in mammalian A549 cells demonstrate that these IONPs are biocompatible and can also produce significant T2/T2* contrast enhancement in IONPs-labeled cells. Furthermore, excitation-wavelength dependent photoluminescence was observed under one- and two-photon excitation.
Discussion:
The obtained results indicated that IONPs could be used for fluorescence label-free bioimaging at multiple wavelengths, which was proven by multiphoton imaging of IONPs internalization in A549 cancer cells.
