title: Design maps for the hyperthermic treatment of tumors with superparamagnetic nanoparticles.
abstract: A plethora of magnetic nanoparticles has been developed and investigated under different alternating magnetic fields (AMF) for the hyperthermic treatment of malignant tissues. Yet, clinical applications of magnetic hyperthermia are sporadic, mostly due to the low energy conversion efficiency of the metallic nanoparticles and the high tissue concentrations required. Here, we study the hyperthermic performance of commercially available formulations of superparamagnetic iron oxide nanoparticles (SPIOs), with core diameter of 5, 7 and 14 nm, in terms of absolute temperature increase ΔT and specific absorption rate (SAR). These nanoparticles are operated under a broad range of AMF conditions, with frequency f varying between 0.2 and 30 MHz; field strength H ranging from 4 to 10 kA m(-1); and concentration cMNP varying from 0.02 to 3.5 mg ml(-1). At high frequency field (∼30 MHz), non specific heating dominates and ΔT correlates with the electrical conductivity of the medium. At low frequency field (<1 MHz), non specific heating is negligible and the relaxation of the SPIO within the AMF is the sole energy source. We show that the ΔT of the medium grows linearly with cMNP , whereas the SARMNP of the magnetic nanoparticles is independent of cMNP and varies linearly with f and H(2) . Using a computational model for heat transport in a biological tissue, the minimum requirements for local hyperthermia (Ttissue >42°C) and thermal ablation (Ttissue >50°C) are derived in terms of cMNP , operating AMF conditions and blood perfusion. The resulting maps can be used to rationally design hyperthermic treatments and identifying the proper route of administration - systemic versus intratumor injection - depending on the magnetic and biodistribution properties of the nanoparticles.
authors: Department of Translational Imaging, The Methodist Hospital Research Institute, Houston, Texas, United States of America.
authors: Antonio
authors: A
authors: Cervadoro
authors: Chiara
authors: C
authors: Giverso
authors: Rohit
authors: R
authors: Pande
authors: Subhasis
authors: S
authors: Sarangi
authors: Luigi
authors: L
authors: Preziosi
authors: Jarek
authors: J
authors: Wosik
authors: Audrius
authors: A
authors: Brazdeikis
authors: Paolo
authors: P
authors: Decuzzi
mesh_terms: D006801:Humans; D006979:Hyperthermia, Induced; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D009369:Neoplasms / Q000628:therapy*