Ultra-low gadolinium doping in multi-core iron oxide enables efficient dual-mode MRI and magnetic hyperthermia: a...

Area of Science:

• Nanomaterials Science
• Biomedical Engineering
• Materials Chemistry
• Oncology

Background:

• Cancer theranostics require multifunctional platforms for simultaneous diagnosis and therapy.
• Maghemite (γ-Fe₂O₃) nanoparticles offer potential for MRI and magnetic hyperthermia treatment (MHT).
• Optimizing nanoplatform performance for both modalities is crucial for effective cancer treatment.

Purpose of the Study:

• To develop novel multifunctional nanoplatforms for cancer theranostics using ultra-low gadolinium (Gd³⁺) doping.
• To investigate the impact of Gd³⁺ doping on the properties of maghemite (γ-Fe₂O₃) nanoflowers for MRI and MHT.
• To establish a tunable balance between MRI contrast enhancement and MHT efficacy.

Main Methods:

• Synthesis of Gd³⁺-doped γ-Fe₂O₃ nanoflowers with controlled doping concentrations (up to 1.7 mol%).
• Characterization using X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and SQUID magnetometry.
• Evaluation of MHT performance under alternating magnetic fields (AMF) and MRI relaxivity measurements at 7 T.

Main Results:

• Ultra-low Gd³⁺ doping significantly altered material properties, creating surface defects and enhancing magnetic anisotropy without compromising the γ-Fe₂O₃ phase.
• The Gd_0.011Fe_1.989O₃ sample demonstrated superior MHT performance with high Intrinsic Loss Power (ILP).
• Gd³⁺ doping markedly improved both longitudinal (r₁) and transverse (r₂) relaxivities, with Gd_0.022Fe_1.978O₃ achieving an exceptional r₂ value and high r₂/r₁ ratio for T₂-weighted MRI.

Conclusions:

• Ultra-low Gd³⁺ doping is a novel strategy to engineer multifunctional maghemite nanoflowers for cancer theranostics.
• Defect engineering and tailored multi-core architecture synergistically optimize the structure-property-function relationship.
• The developed nanoplatforms offer a tunable balance for dual-mode T₁/T₂ MRI and MHT, paving the way for safer and more effective cancer treatment.