6th of December 2018 the first edition of the book entitled “Nanomaterials for Magnetic and Optical Hyperthermia Applications” was published by Elsevier. This book focuses on the design, fabrication and characterization of nanomaterials for in vitro and in applications. Anna Laromaine, researcher at the N&N group, and Laura González-Moragas, graduated PhD student at the N&N group, are coauthors of the chapter nine included in this book: Invertebrate Models for Hyperthermia: What We Learned From Caenorhabditis elegans and Hydra vulgaris.
Abstract: Magnetic hyperthermia is an oncological therapy where magnetic nanostructures, under a radiofrequency field, act as heat transducers increasing tumour temperature and killing cancerous cells. Nanostructure heating efficiency depends both on the field conditions and on the nanostructure properties and mobility inside the tumour. Such nanostructures are often incorrectly bench-marketed in the colloidal state and using field settings far off from the recommended therapeutic values. Here, we prepared nanoclusters composed of iron oxide magnetite nanoparticles crystallographically aligned and their specific absorption rate (SAR) values were calorimetrically determined in physiological fluids, agarose-gel-phantoms and ex vivo tumours extracted from mice challenged with B16-F0 melanoma cells. A portable, multipurpose applicator using medical field settings; 100 kHz and 9.3 kA m−1, was developed and the results were fully analysed in terms of nanoclusters’ structural and magnetic properties. A careful evaluation of the nanoclusters’ heating capacity in the three milieus clearly indicates that the SAR values of fluid suspensions or agarose-gel-phantoms are not adequate to predict the real tissue temperature increase or the dosage needed to heat a tumour. Our results show that besides nanostructure mobility, perfusion and local thermoregulation, the nanostructure distribution inside the tumour plays a key role in effective heating. A suppression of the magnetic material effective heating efficiency appears in tumour tissue. In fact, dosage had to be increased considerably, from the SAR values predicted from fluid or agarose, to achieve the desired temperature increase. These results represent an important contribution towards the design of more efficient nanostructures and towards the clinical translation of hyperthermia.
As the new academic course starts, we have new members in the N&N group: We welcome Michaela and Gustavo!
Michaela comes from the Czech Republic and she is going to work with Marti Gich for a short period:
I am going to study study epsilon-Fe2O3 in detail: its synthesis, properties, and applications. In the laboratory, I am going to study sol-gel process for preparation of iron oxide nanoparticles. Afterwards, the nanoparticles will be characterized by different techniques to examine their composition, structure and magnetic properties.
Gustavo is a permanent researcher of CONICET, Argentina. He will be at the ICMAB for a year in N&N group thanks to a grant from the Argentine government.
My current scientific interests are focused on magnetic colloids, dipolar interactions between particles and effects of liquid matrix solidification on the final distribution of nanoparticles as well as distribution of their anisotropy orientations. I am also interested on magnetic systems relevant to potential applications in medicine. In particular, heat dissipation for magnetic hyperthermia and magnetic induced transport for magnetofection gene therapy. At the N&N group, I will work on the synthesis and characterization of anisotropic magnetic nanoparticles as generators of magnetomechanical stimuli inside cancer cells as a new way to induce apoptotic cell death. We will work in performing insitu observation by optical microscopy of magnetic-microparticles movements induced by rotating magnetic fields.
This paper is the result of a collaboration with theInstituto de Física La Plata (IFLP- CONICET) at the Universidad Nacional de La Plata (UNLP) in Argentina.
Congratulations!
Abstract:
Magnetic hyperthermia, a modality that uses radio frequency heating assisted with single-domain magnetic nanoparticles, is becoming established as a powerful oncological therapy. Much improvement in nanomateriales development, to enhance their heating efficiency by tuning the magnetic colloids properties, has been achieved.
However, methodological standardization to accurately and univocally determine the colloids properties required to numerically reproduce specific heating efficiency using analytical expressions still holds.Thus, anticipating the hyperthermic performances of magnetic colloids entails high complexity due to polydispersity, aggregation and dipolar interaction always present in real materials to a more or lesser degree.
Here, by numerically simulating experimental results and using real biomedical aqueous colloids, we analyse and compared several approaches to reproduce experimental specific absorption rate values. Then, we show that relaxation time, determined using a representative mean activation energy consistently derived from four independent experiments accurately reproduces experimental heating efficiencies.
Moreover, the so-derived relaxation time can be used to extrapolate the heating performance of the magnetic nanoparticles to other field conditions within the framework of the linear response theory. We thus present a practical tool that may truly aid the design of medical decisions.
