Intermittent time-set technique controlling the temperature of magnetic-hyperthermia-ablation for tumor therapy

Abstract

Magnetic-hyperthermia-ablation is considered as an effective and minimally invasive technology for tumor therapy. However, inappropriate temperature control could induce an excessively high temperature which brings potential safety problems and limits clinical transformation of this technique. Herein, aiming to control the temperature during magnetic hyperthermia ablation, we develop an intermittent time-set technique for temperature control in magnetic hyperthermia ablation of tumors using a polylactic-coglycolic acid (PLGA)-Fe 3 O 4 implant. In vitro, the intermittent time is set as follows: tubes are continuously heated for 110 seconds. Then the heating process is paused for 20 seconds, and then the tubes are reheated for 10 seconds, followed by repeating the last two processes. The temperature elevation profile upon magnetic hyperthermia interestingly also demonstrates good controllability despite some differences in time-setting between in vitro and in vivo. The in vivo results show the temperature fluctuates within the range of 6.45 AE 1.34 C after reaching the target temperature.Furthermore, we observe the deformation of an implant employing three-dimensional (3D) ultrasound to better understand the temperature change. The results show no significant deformation of the implant after being heated. The microscopic images prove that this simple technique can successfully cause tumor regression. This temperature control technique provides great benefits for hyperthermia ablation against tumors, advancing the magnetic hyperthermal ablation technology in clinical translation.

Deep-tissue localization of magnetic field hyperthermia using pulse sequencing

“…Most MFH laboratories use much lower amplitudes, of order 10-15 kA/ m [42], for which the eddy currents, especially in small animal models, are negligible. This may explain why pulse MFH has been seldom used to date, with the exception of a few reports on its use, to obtain high thermal doses and cell death in vitro [43]; to maintain constant temperatures in a murine treatment model [44]; and as part of a pulsatile drug release strategy [45,46]. No previous studies have focused on dose-localization and biological outcomes per se, as in this work.…”

Synthesis and Cytotoxicity Assessment of Citrate-Coated Calcium and Manganese Ferrite Nanoparticles for Magnetic Hyperthermia

“…This means that these NPs show significant heating capability at the lowest field frequency studied. C), and that the body temperature is around 37 • C, these NPs were capable of achieving the mild hyperthermia-required temperature and acting as hyperthermia agents, which could be controlled through an intermittent time-set technique [33].…”

“…At this amplitude and frequencies of 270.6 kHz and 161.6 kHz, MnFe2O4 NPs reached a temperature variation of ~5 °C in 120 s, while the presence of 20% calcium led to a better heating performance of the ferrite, achieving a variation of ~6 °C and ~7 °C at 270.6 kHz and 161.6 kHz, respectively. Considering that the viability of cancer cells can be affected by mild hyperthermia (~42 °C), and that the body temperature is around 37 °C, these NPs were capable of achieving the mild hyperthermia-required temperature and acting as hyperthermia agents, which could be controlled through an intermittent time-set technique [33].…”

Review on the advancements of magnetic gels: towards multifunctional magnetic liposome-hydrogel composites for biomedical applications

“…For example, Engelmann et al [107] demonstrated that tissue damage depends not only on the bulk temperature and duration of treatment, but also on the cell type and thermal energy deposited per cell during treatment. Concerning the inconvenient thermal control through the dosage of nanoparticles, as large dosage can induce excessive temperature and low dosage might not be enough to kill cancer cells, Tang et al [108] have recently demonstrated that a simple intermittent time-set technique could be used to control and maintain the enhanced temperature during the magnetic hyperthermia in cancer therapy.…”