Multifunctional approaches based on thermal nanotherapies: heat generation, therapeutic efficiency and limitations
Thermal nanotherapies as magnetic hyperthermia (MHT) and photothermal therapy (PTT) are two promising emergent treatments and non-invasive approaches for tumor ablation, where localized heat generation is mediated by magnetic and photo-activatable nanomaterials . Until very recently, these thermal nanotherapies, have been developed separately: MHT is mainly focused on the use of magnetic iron oxide nanoparticles due to their excellent biodegradability , while metallic nanoparticles such as gold nanomaterials are often preferred due to their strong absorption cross sections . They have recently begun to intersect due to the recent discovery and use of photothermal properties of iron oxide nanostructures or to the use of magneto-photothermal hybrids, which efficiently combine both heating features in one-single object.
A comprehensive comparison of the heating efficiency of magneto- versus photo-thermal effect is presented, where different magnetic nanoparticles have been confronted (iron oxides, cobalt ferrite, spheres, cubes, flowers) with different metallic nanoparticles in aqueous, cellular, and tumoral environment . Intracellular processing markedly impacted MHT, while endosomal sequestration could have a positive effect for PTT. In the search for the most therapeutically viable modality, the effect of nanoparticle concentration and the experimental exposure parameters (magnetic field strengths/frequencies and laser power densities) have been investigated. Several combinations of thermal nanotherapies with other therapeutic nanofunctionalities will be presented.
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