Abstract
Materials with 1st order antiferromagnetic (AFM) to high-magnetization (MM) phase transition known for their inverse magnetocaloric effect, abrupt rise in magnetization and magnetoelastic coupling, are promising for application in combined simultaneous diagnosis and targeted cancer therapy. A therapy that combines alternating-current (ac) and direct-current (dc) magnetic fields for simultaneous magnetic hyperthermia therapy (MHT) and magnetic resonance imaging (MRI), using same magnetic particles for heating and as contrast agents. We report a proof-of-concept study on the induction heating ability of 1st order metamagnetic material with moderate specific absorption rates (SAR) and no tendency for agglomeration, for potential MHT and MRI cancer therapy. CoMnSi, a metamagnetic antiferromagnet (MM) was used in this study because of its desirable ability to rapidly switch from a low to high magnetization state in an applied dc bias field condition without particle agglomeration on field removal. The results showed that the magnetization switched from < 20 Am2kg-1 at 0.75 T to about 53.31 Am2kg-1 at 1.0 T applied dc field, a field large enough for magnetic resonance imaging. An SAR value of 10.7 Wg-1 was obtained under an ac field of 31.0 kAm-1 at 212.0 kHz. When combined with a dc bias field of 1.0 T, SAR values of 9.83 Wg-1 and 6.65 Wg-1 were obtained in the directions 45° and 90° away from the dc bias field direction respectively. These SAR values obtained from CoMnSi particles in the presence of simultaneous ac and dc magnetic field bias are in comparison, at least 25 times greater than those obtained from 2nd order magnetic phase transition Fe3O4 suspension. It is observed that Fe3O4 particles showed large suppression of SAR, and agglomeration under the same experimental conditions. This study shows the great potential of 1st order phase transition metamagnets for simultaneous MHT and MRI cancer therapy using MRI equipment.
Highlights
There is a growing interest in finding biomedical materials with multifunctional properties, such as magnetic materials, for application in consolidated diagnosis, targeted treatment and real-time monitoring of cancer treatment, known as cancer theranostics.[1,2,3,4,5,6,7,8] Magnetic particles (MP) are promising candidates as cancer theranostics agents[1,2,3,4] due to their ease of manipulation by non-invasive external magnetic field stimuli.[9]
These specific absorption rates (SAR) values obtained from CoMnSi particles in the presence of simultaneous ac and dc magnetic field bias are in comparison, at least 25 times greater than those obtained from 2nd order magnetic phase transition Fe3O4 suspension
We have demonstrated the use of CoMnSi particles with 1st order metamagnetic phase transition for heat generation by magnetic field induction
Summary
There is a growing interest in finding biomedical materials with multifunctional properties, such as magnetic materials, for application in consolidated diagnosis, targeted treatment and real-time monitoring of cancer treatment, known as cancer theranostics.[1,2,3,4,5,6,7,8] Magnetic particles (MP) are promising candidates as cancer theranostics agents[1,2,3,4] due to their ease of manipulation by non-invasive external magnetic field stimuli.[9]. A theoretical study by Umut et al on heating properties of FM NiFe2O4 particle for simultaneous hyperthermia and MRI application yielded same conclusions as those from earlier studies.[12] The suppression or total cancelation of heating ability of FM and FiM systems is due to magnetization saturation of these particles in the presence of an applied dc field μoH, which impedes alignment of magnetic moments with the applied ac field.[10,13,32] These findings highlight the need for alternative materials to replace the present SPM, FM and FiM materials with a finite magnetization ground state in MHT and MRI theranostic applications. CoMnSi has been chosen in this study because, below Tt it is a 1st order AFM metamagnet with abrupt rise in magnetization, which is a desirable property for combined simultaneous MHT and MRI theranostic cancer treatment
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