Towards optimal thermal distribution in magnetic hyperthermia

Abstract

A linear combination of spherically symmetric heat sources is shown to provide optimal stationary thermal distribution in magnetic hyperthermia. Furthermore, such spatial location of heat sources produces suitable temperature distribution in biological medium even for assemblies of magnetic nanoparticles with a moderate value of specific absorption rate (SAR), of the order of 100–150 W/g. We also demonstrate the advantage of using assemblies of spherical magnetic nanocapsules consisting of metallic iron nanoparticles covered with non magnetic shells of sufficient thickness in magnetic hyperthermia. Based on numerical simulation we optimize the size and geometric structure of biocompatible spherical capsules in order to minimize the influence of strong magneto-dipole interaction between closely spaced nanoparticles. It is shown that assembly of capsules can provide sufficiently high SAR values of the order of 250–400 W/g at moderate amplitudes H0 = 50–100 Oe and frequencies f = 100–200 kHz of alternating magnetic field, being appropriate for application in clinics.

Nanomedicine for autophagy modulation in cancer therapy: a clinical perspective

“…Metallic nanoparticles allow the use of a wide variety of techniques (laser, ionizing radiation and microwaves) to induce heat at sites of nanoparticle accumulation [ 148 ]. Magnetic hyperthermia (MH) allows for remote heat induction localized in tumor specific area by using magnetic energy losses in magnetic nanoparticles through administration of alternate magnetic field (AMF), which reduces the side effects at the surrounding healthy tissues [ 149 ].…”

“…Furthermore, various works highlight magnetic hyperthermia as a promising adjuvant strategy to radiation and chemotherapy against cancer [ 149 ]. Alternatively, the exposure of metallic nanoparticles to laser radiation near their plasmon-resonant absorption band allows local heating of nanoparticle-labeled cells avoiding effects in surrounding healthy tissues.…”

Specific absorption rate of randomly oriented magnetic nanoparticles in a static magnetic field

“…It is known [ 1 – 2 7 ] that optimized assemblies of magnetic nanoparticles are promising for the use in magnetic hyperthermia. However, it is necessary to strictly control the spatial distribution of magnetic nanoparticles in the tumor in order to exclude undesirable thermal effects on healthy tissues surrounding the tumor [ 30 ]. The combination of MH and MPI techniques seems promising, as it will allow one to localize the heat release in the tumor-affected organ more accurately and to minimize the thermal effect on healthy tissues, which may also contain a certain amount of magnetic nanoparticles.…”

Specific absorption rate of randomly oriented magnetic nanoparticles in a static magnetic field

“…It is known [1,2,5] that optimized assemblies of magnetic nanoparticles are promising for use in magnetic hyperthermia. However, it is necessary to strictly control the spatial distribution of magnetic nanoparticles in the tumor in order to exclude undesirable thermal effects on healthy tissues surrounding the tumor [28]. The combination of MH-MPI techniques seems promising, as it will allow localizing the heat release in the tumor-affected organ more accurately and minimizing the thermal effect on healthy tissues, which may also contain a certain amount of magnetic nanoparticles.…”