title: Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model.
abstract: Magnetic iron oxide nanoparticles (MNPs) have been developed for magnetic fluid hyperthermia (MFH) cancer therapy, where cancer cells are treated through the heat generated by application of a high frequency magnetic field. This heat has also been proposed as a mechanism to trigger release of chemotherapy agents. In each of these cases, MNPs with optimal heating performance can be used to maximize therapeutic effect while minimizing the required dosage of MNPs. In this study, the heating efficiencies (or specific absorption rate, SAR) of two types of MNPs were evaluated experimentally and then predicted from their magnetic properties. MNPs were also incorporated in the core of poly(ethylene glycol-b-caprolactone) micelles, co-localized with rhodamine B fluorescent dye attached to polycaprolactone to monitor local, nanoscale temperatures during magnetic heating. Despite a relatively high SAR produced by these MNPs, no significant temperature rise beyond that observed in the bulk solution was measured by fluorescence in the core of the magnetic micelles. MNPs were also incorporated into a macro-scale agarose gel system that mimicked a tumor targeted by MNPs and surrounded by healthy tissues. The agarose-based tumor models showed that targeted MNPs can reach hyperthermia temperatures inside a tumor with a sufficient MNP concentration, while causing minimal temperature rise in the healthy tissue surrounding the tumor.
authors: The University of Alabama, Department of Chemical and Biological Engineering, Tuscaloosa, AL, United States. Electronic address: rrshah@crimson.ua.edu.
authors: Rhythm R
authors: RR
authors: Shah
authors: The University of Alabama, Department of Chemical and Biological Engineering, Tuscaloosa, AL, United States. Electronic address: ardombrowsky@crimson.ua.edu.
authors: Alexander R
authors: AR
authors: Dombrowsky
authors: The University of Alabama, Department of Chemistry, Tuscaloosa, AL, United States. Electronic address: alpaulson@crimson.ua.edu.
authors: Abigail L
authors: AL
authors: Paulson
authors: The University of Alabama, Department of Chemistry, Tuscaloosa, AL, United States. Electronic address: mpjohnson1@crimson.ua.edu.
authors: Margaret P
authors: MP
authors: Johnson
authors: The University of Alabama, Department of Chemistry, Tuscaloosa, AL, United States. Electronic address: dnikles@mint.ua.edu.
authors: David E
authors: DE
authors: Nikles
authors: The University of Alabama, Department of Chemical and Biological Engineering, Tuscaloosa, AL, United States. Electronic address: cbrazel@eng.ua.edu.
authors: Christopher S
authors: CS
authors: Brazel
mesh_terms: D000818:Animals; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D055909:Magnetic Field Therapy / Q000379:methods*; D008954:Models, Biological; D053758:Nanoparticles / Q000737:chemistry*; D009369:Neoplasms / Q000628:therapy*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology; D012685:Sepharose / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D011092:Polyethylene Glycols; D012685:Sepharose
keywords: Agarose gel tumor model; Hyperthermia; Iron oxide nanoparticles; Local nanoparticle temperature; Magnetic field; Magnetic heating; Power generation; Specific absorption rate