Thermographical Method to Assess the Performance of Magnetic Nanoparticles in Hyperthermia Experiments through Spatiotemporal Temperature Profiles

D. P. VALDÉS; T. E. TORRES; A. C. MORENO MALDONADO; G. URRETAVIZCAYA; M. S. NADAL; M. VASQUEZ MANSILLA; R. D. ZYSLER; G. F. GOYA; E. DE BIASI; E. LIMA JR.

Puerto Varas

Workshop; XII Latin American Workshop on Magnetism, Magnetic Materials, & their Applications (LAW3M) 2023; 2023

Universidad Técnica Federico Santa María

For magnetic fluid hyperthermia (MFH), dissimilar results are usually obtained whencharacterizing magnetic nanoparticles (MNPs) in vitro versus dispersed in solvents due toviscosity effects or MNP aggregation [1], thus characterizing MNP systems in media such aspolyacrylamide gels (PAGs) that can reproduce cytosol viscosity [2] is key. Moreover,conventional fiber-optic temperature measurements can monitor only one spot in the sample.A way of following the temperature evolution noninvasively inside cell cultures, tissues ortumors is needed, as well as understanding heat transfer in these systems where temperaturegradients and heat losses are prevalent [3].We unveil a novel method to generate 2D temperature maps for MNP samples in MFHexperiments [4]. We tested it by analyzing two types of 8% PAG with MNPs: oneconventionally polymerized (dispersed) and another one polymerized inside a coil with anamplitude of the ac field of H = 32 kA/m and a frequency of f = 350 kHz (oriented), whereelongated agglomerates were formed. MNP concentrations of both 0.1 and 0.5 wt% were used.Power absorption (PA) experiments were performed in these PAGs (at the same ac fieldconditions) and the temperature increment evolution was monitored through the recording ofvideos with an IR thermographical camera. The processing of the IR camera measurementsallowed us to generate spatiotemporal (2D) temperature profiles (see Fig. 1) and the analysisof these profiles allowed us to follow not only the increment of temperature during MFHexperiments but also thermodynamic parameters such as energy, power and heat flux. We alsoidentified spatial inhomogeneities through the temperature maps, which highlights that a 2Danalysis could benefit the interpretation of results obtained in biological and medical uses.