Iron-Oxide Nanoparticles Embedded in 3D-Printed PLA/HA Scaffolds for Magnetic Hyperthermia Therapy: An Experimental-Numerical Analysis of Thermal Behavior.

Hyperthermia is nowadays intensively investigated as a promising strategy to improve the therapeutic efficacy against different types of cancer and resistant infections. In particular, the remote generation of localized hyperthermia by magnetic field through iron-oxide nanoparticles (IONPs) offers good thermal conductivity in a controlled area. The incorporation of these IONPs in 3D-printed scaffolds designed for bone tissue regeneration has been scarcely addressed in the literature. This strategy would add the potential of magnetic-mediated hyperthermia against remnant cancer or resistant infections in the damaged tissue area to these personalized bone-related scaffolds. The present work proposes two methodologies to obtain 3D-printed bone-related scaffolds with magnetic properties: 1-Direct 3D printing with IONPs-embedded polylactic acid (PLA) and hydroxyapatite (HA), resulting in a uniform distribution of IONPs; and 2-Drop coating on 3D-printed PLA/HA scaffolds, resulting in the IONPs being concentrated on the scaffold surface. Physicochemical/mechanical characterizations were performed to confirm the IONPs' distributions and viability assays were carried out to validate the absence of cytotoxicity. Hyperthermia tests (314 kHz) were carried out, including the simulation/validation of the experimental equipment, to establish optimal distances from the planar coil. Temperature-time/distance curves were obtained and parametrized (R > 0.96) for both methodologies in relation to the contribution of IONPs (0.20-1.00 mg), their distribution in the scaffold (uniform/concentrated), the electric-current intensity, and the distance. The results validated both methodologies to obtain personalized 3D-printed PLA/HA scaffolds with magnetic properties, reaching the required moderate/ablative hyperthermia levels.