Intratumoral thermal reading during photo-thermal therapy by multifunctional fluorescent nanoparticles

et al.The tremendous development of nanotechnology is bringing us closer to the dream of clinical application of nanoparticles in photothermal therapies of tumors. This requires the use of specific nanoparticles that must be highly biocompatible, efficient light-to-heat converters and fluorescent markers. Temperature reading by the heating nanoparticles during therapy appears of paramount importance to keep at a minimum the collateral damage that could arise from undesirable excessive heating. In this work, this thermally controlled therapy is possible by using Nd3+ ion-doped LaF3 nanocrystals. Because of the particular optical features of Nd3+ ions at high doping concentrations, these nanoparticles are capable of in vivo photothermal heating, fluorescent tumor localization and intratumoral thermal sensing. The successful photothermal therapy experiments here presented highlight the importance of controlling therapy parameters based on intratumoral temperature measurements instead of on the traditionally used skin temperature measurements. In fact, signifi cant differences between intratumoral and skin temperatures do exist and could lead to the appearance of excessive collateral damage. These results open a new avenue for the real application of nano-particle-based photothermal therapy at clinical level.The work was supported by the Ministerio de Innovación y Ciencia of Spain under projects MAT2010–16161 and MAT2013–47395-C4–1-R. P.H. thanks the Spanish Ministerio de Economia y Competitividad (MINECO) for a Juan de la Cierva grant. The authors also thank the Brazilian agencies FAPEAL-Fundação de Amparo a Pesquisa do Estado de Alagoas (Project PRONEX 2009–09–006), FINEP (Financiadora de Estudos e Projetos), CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) through Grant INCT NANO(BIO)SIMES, and CAPES (Coordenadoria de Aperfeiçoamento de Pessoal de Ensino Superior). D.J. (Pesquisador Visitante Especial (PVE)-CAPES) thanks the CAPES by means of the Project PVE number A077/2013. B. del Rosal thanks Universidad Autónoma de Madrid for an FPI grant.Peer Reviewe