Expansion of Thermometry in Magnetic Hyperthermia Cancer Therapy: Antecedence and Aftermath

Abstract

Magnetic hyperthermia cancer therapy (MHCT) is a promising antitumor therapy based on the generation of heat by magnetic nanoparticles under the influence of an alternating-current magnetic field. However, an often-overlooked factor hindering the translation of MHCT to clinics is the inability to accurately monitor temperature, thereby leading to erroneous thermal control. It is significant to address ‘thermometry’ during magnetic hyperthermia because numerous factors are affected by the magnetic fields employed, rendering traditional thermometry methods unsuitable for temperature estimation. Currently, there is a dearth of literature describing appropriate techniques for thermometry during MHCT. This review offers a general outline of the various modes of conventional thermometry as well as cutting-edge techniques operating at cellular/nanoscale levels (nanothermometry) as prospective thermometers for MHCT in the future.

Magnetoliposomes with Calcium-Doped Magnesium Ferrites Anchored in the Lipid Surface for Enhanced DOX Release

“…The most commonly used energy sources are alternating magnetic fields (AMF) [ 39 , 40 , 41 , 42 ]—magnetic hyperthermia—and near-infrared (NIR) laser light irradiation [ 43 , 44 , 45 ]—photothermal therapy. One of the advantages of using NIR-induced photothermal hyperthermia over AMF-induced hyperthermia is related to its higher tissue-penetrating capabilities, being minimally invasive and more targeted to a specific part of the body [ 46 , 47 ]. In turn, hyperthermia is an adjuvant therapy proposed for the treatment of cancer, where tumor cells are affected by the rise of the local temperature to values between 43 °C and 46 °C [ 47 , 48 ].…”

“…One of the advantages of using NIR-induced photothermal hyperthermia over AMF-induced hyperthermia is related to its higher tissue-penetrating capabilities, being minimally invasive and more targeted to a specific part of the body [ 46 , 47 ]. In turn, hyperthermia is an adjuvant therapy proposed for the treatment of cancer, where tumor cells are affected by the rise of the local temperature to values between 43 °C and 46 °C [ 47 , 48 ]. The increase in temperature enhances the chemotherapy therapeutic effect by inducing greater perfusion within the tumor, which leads to a larger internalization of chemotherapy drugs [ 49 , 50 , 51 ].…”

Fiber-Based Ratiometric Optical Thermometry with Silicon Vacancy in Microdiamonds

“…Current technological advancements in micro or nanoelectronics, − nanophotonics, , biophotonics, microfluidics, , and nanomedicine have reached a point where conventional thermometry is no longer applicable for measuring the temperature in the microscale limit due to the drop of spatial resolution to the micron level. To design reliable and efficient microelectronic devices and components, where their operational performance is often constrained by efficient heat dissipation, it is necessary to measure temperature precisely at the microscale.…”

Local Temperature Increments and Induced Cell Death in Intracellular Magnetic Hyperthermia

“… 6 Consequently, to make this approach viable, a massive amount of MNPs had to be injected, and thermocouples (invasive) or luminescent thermometers (remote detection) had to be placed around a tumor to avoid overheating in the surrounding healthy tissue. 7 − 12 Yet there is a promising alternative to this unfeasible procedure, which turns magnetic hyperthermia back into an ideal, nontoxic, and noninvasive proposition: cancer cell death can be attained by small amounts of heat generated at thermosensitive intracellular sites, without significantly increasing the average temperature of the whole tumor (or even that of the cell). This local intracellular hyperthermia hypothesis 2 , 4 , 13 can only hold true if the heat power generated in the MNPs reaches temperature increments that are high enough to induce irreversible local damage to the surrounding cell biomolecules and consequently trigger cell death.…”

“…The emergence of magnetic hyperthermia a few decades ago seemed to represent a great opportunity to achieve this goal. − In the ideal case, nontoxic iron oxide magnetic nanoparticles (MNPs) could be selectively internalized in tumor tissue and then be heated by a noninvasive external alternating magnetic field (AMF), thereby causing tumor cell destruction without affecting the rest of the body. , However, it soon became clear that the intrinsic low heating power of MNPs allowed for human use at conditions for magnetic field induction represented a severe limitation and restricted the general implementation of this technique in hospitals . Consequently, to make this approach viable, a massive amount of MNPs had to be injected, and thermocouples (invasive) or luminescent thermometers (remote detection) had to be placed around a tumor to avoid overheating in the surrounding healthy tissue. − Yet there is a promising alternative to this unfeasible procedure, which turns magnetic hyperthermia back into an ideal, nontoxic, and noninvasive proposition: cancer cell death can be attained by small amounts of heat generated at thermosensitive intracellular sites, without significantly increasing the average temperature of the whole tumor (or even that of the cell). This local intracellular hyperthermia hypothesis ,, can only hold true if the heat power generated in the MNPs reaches temperature increments that are high enough to induce irreversible local damage to the surrounding cell biomolecules and consequently trigger cell death.…”