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Global Translational Medicine SPION for cancer theranostics

Table 3. Comprehensive review of commonly used methods for superparamagnetic iron oxide nanoparticle synthesis
Synthesis method Coprecipitation Microemulsion Hydrothermal Thermal Sonochemical
Decomposition
Solvent Water Organic solvent Water-ethanol Organic solvent Organic solvent
Reaction condition Organic solvent 20 – 50°C High temperature and High Temperature Room temperature
high pressure
Duration Minutes Hours Hours Hours–days Minutes
Particle size and size 5 – 20 nm, broad 2 – 20, narrow 20 – 200 nm, narrow 4 – 20 nm, narrow 5 – 15 nm, narrow
distribution
Shape control Not good Good Very good Very good Good
Saturation Moderate (30 – 60) Moderate (40 – 60) High (60 – 80) Very High (70 – 90) Moderate (45 – 65)
magnetization (emu/g)
Dispersity profile Polydisperse Relatively monodisperse Monodisperse Monodisperse Monodisperse
Yield Scalable Low Medium Scalable Medium
Note: Information are derived from Hu et al., Lu et al. .
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SPIONs in aqueous solutions (hydro) or organic solvents
(solvo) using a Teflon-lined stainless steel autoclave
at temperatures ranging from 130 to 250°C for 8 – 72 h
under 0.3 – 4 MPa pressure. This method produces
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a clear, homogeneous solution by dissolving ferric
chloride, sodium acetate, and polyethylene glycol (PEG)
in ethylene glycol, followed by constant stirring for
30 min. The autoclave is then filled with the resultant
solution, sealed, and heated to 200°C for 8 – 72 h. In this
process, PEG serves as the surfactant to prevent particle
aggregation, sodium acetate as the electrostatic stabilizer,
ethylene glycol as the solvent, and ferric chloride (FeCl )
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as the precursor. The controlled reaction parameters
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yield highly monodispersed NPs with uniform shapes.
The surface charge can be adjusted by varying the choice Figure 2. Diagram illustrating magnetic drug targeting under the
of solvent and precursor. The SPIONs can be further control of an external magnetic field. Reproduced from Shabatina et al. .
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functionalized by coating them with polymers or silica to Copyright 2020 Authors.
enhance their water dispensability or hydrophilicity. This Abbreviation: SPIONs: Superparamagnetic iron oxide nanoparticles.
functionalization is more controllable than in the thermal
decomposition method, although the synthesis process is oleic acid. Precise control over reagent ratios and reaction
more complex than the coprecipitation method. SPIONs conditions is crucial for achieving the desired nanoparticle
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produced using this route are versatile for applications in size and morphology. For instance, Yang et al.
MRI, hyperthermia, and drug delivery. A schematic figure successfully synthesized monodispersed Fe O nanocubes
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illustrating magnetic drug targeting under the application (6.5 – 30 nm) by thermally decomposing ferric acetate in
of an external magnetic field is presented in Figure 2. a mixture of 1,2-hexadecanediol, oleic acid, oleylamine,
and benzyl ether at 200°C. The SPIONs produced using
2.4. Thermal decomposition method this technique are monodispersed and require ligand
The thermal decomposition method is an effective exchange for aqueous dispersion. SPIONs synthesized by
technique for synthesizing high-quality, monodispersed this method are excellent for MRI, multimodal imaging,
Fe O NPs with smaller sizes and high crystallinity, and MHT due to higher crystallinity and superior
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outperforming other synthesis methods. This approach magnetic properties. However, they require additional
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involves the decomposition of organometallic precursors, surface modifications to improve biocompatibility for
such as tris(acetylacetonato) iron(III) (Fe[acac] ) and biomedical applications. Despite its advantages, the
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iron (III) cupferronate (Fe[cup] ), in high-boiling organic thermal decomposition method faces limitations in
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solvents in the presence of stabilizing surfactants like biomedical applications due to the requirement for high
Volume 4 Issue 2 (2025) 35 doi: 10.36922/gtm.8464