Feasibility Study on the Radiation Dose by Radioactive Magnetic Core-Shell Nanoparticles for Open-Source Brachytherapy

Magnetic hybrid Pd/Fe-oxide nanoparticles meet the demands for ablative thermo-brachytherapy

OBJECTIVE

To investigate the potential of hybrid Pd/Fe-oxide magnetic nanoparticles designed for thermo-brachytherapy of breast cancer, considering their specific loss power (SLP) and clinical constraints in the applied magnetic field.

METHODS

Hybrid nanoparticles consisting of palladium-core and iron oxide shell of increasing thickness, were suspended in water and their SLPs were measured at varying magnetic fields (12-26 mT peak) and frequencies (50-730 kHz) with a commercial alternating magnetic field generator (magneTherm™ Digital, nanoTherics Ltd.).

RESULTS

Validation of the heating device used in this study with commercial HyperMag-C nanoparticles showed a small deviation (±4%) over a period of 1 year, confirming the reliability of the method. The integration of dual thermometers, one in the center and one at the bottom of the sample vial, allowed monitoring of homogeneity of the sample suspensions. SLPs measurements on a series of nanoparticles of increasing sizes showed the highest heating for the diameter of 21 nm (SLP = 225 W/g) at the applied frequencies of 346 and 730 kHz. No heating was observed for the nanoparticles with the size <14 nm, confirming the importance of the size-parameter. The heating ability of the best performing Pd/Fe-oxide-21 was calculated to be sufficient to ablate tumors with a radius ±4 and 12 mm using 10 and 1 mg/mL nanoparticle concentration, respectively.

CONCLUSIONS

Nanoparticles consisting of non-magnetic palladium-core and magnetic iron oxide shell are suitable for magnetic hyperthermia/thermal ablation under clinically safe conditions of 346 kHz and 19.1 mT, with minimal eddy current effects in combination with maximum SLP.

Neutron-activated, plasmonically excitable Fe-Pt-Yb2O3 nanoparticles delivering anti-cancer radiation against human glioblastoma cells

Magnetic nanoparticles can be functionalized in many ways for biomedical applications. Here, we combine four advantageous features in a novel Fe-Pt-Yb2O3 core-shell nanoparticle. (a) The nanoparticles have a size of 10 nm allowing them to diffuse through neuronal tissue. (b) The particles are superparamagnetic after synthesis and ferromagnetic after annealing, enabling directional control by magnetic fields, enhance NMRI contrast, and hyperthermia treatment. (c) After neutron-activation of the shell, they carry low-energetic, short half-life β-radiation from 175Yb, 177Yb, and 177Lu. (d) Additionally, the particles can be optically visualized by plasmonic excitation and luminescence. To demonstrate the potential of the particles for cancer treatment, we exposed cultured human glioblastoma cells (LN-18) to non-activated and activated particles to confirm that the particles are internalized, and that the β-radiation of the radioisotopes incorporated in the neutron-activated shell of the nanoparticles kills more than 98% of the LN-18 cancer cells, promising for future anti-cancer applications.