title: Double rare-earth nanothermometer in aqueous media: opening the third optical transparency window to temperature sensing.
abstract: Owing to the alluring possibility of contactless temperature probing with microscopic spatial resolution, photoluminescence nanothermometry at the nanoscale is rapidly advancing towards its successful application in biomedical sciences. The emergence of near-infrared nanothermometers has paved the way for temperature sensing at the deep tissue level. However, water dispersibility, adequate size at the nanoscale, and the capability to efficiently operate in the second and third biological optical transparency windows are the requirements that still have to be fulfilled in a single nanoprobe. In this work, these requirements are addressed by rare-earth doped nanoparticles with core/shell-architecture, dispersed in water, whose excitation and emission wavelengths conveniently fall within the biological optical transparency windows. Under heating-free 800 nm excitation, double nanothermometry is realized either with Ho3+-Nd3+(1.18-1.34 μm) or Er3+-Nd3+(1.55-1.34 μm) NIR emission band ratios, both displaying equal thermal sensitivities around 1.1% °C-1. It is further demonstrated that, along with the interionic energy transfer processes, the thermometric properties of these nanoparticles are also governed by the temperature dependent energy transfer to the surrounding solvent (water) molecules. Overall, this work presents a novel water dispersible double ratiometric nanothermometer operating in the second and third biological optical transparency windows. The temperature dependent particle-solvent interaction is also presented, which is critical for e.g. future in vivo applications.
authors.affiliation: Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Université du Québec, Varennes, Québec J3X 1S2, Canada. vetrone@emt.inrs.ca.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-4060-4290
authors.initials: A
authors.lastname: Skripka
authors.affiliation: Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Université du Québec, Varennes, Québec J3X 1S2, Canada. vetrone@emt.inrs.ca.
authors.forename: A
authors.initials: A
authors.lastname: Benayas
authors.affiliation: Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Université du Québec, Varennes, Québec J3X 1S2, Canada. vetrone@emt.inrs.ca and Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Via Torino 155/b, I-30170, Venezia-Mestre, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Marin
authors.affiliation: Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Via Torino 155/b, I-30170, Venezia-Mestre, Italy.
authors.forename: P
authors.identifier: http://orcid.org/0000-0003-1604-5265
authors.initials: P
authors.lastname: Canton
authors.affiliation: Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Université du Québec, Varennes, Québec J3X 1S2, Canada. vetrone@emt.inrs.ca.
authors.forename: E
authors.initials: E
authors.lastname: Hemmer
authors.affiliation: Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Université du Québec, Varennes, Québec J3X 1S2, Canada. vetrone@emt.inrs.ca and Centre for Self-Assembled Chemical Structures, McGill University, Montréal, Québec H3A 2K6, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Vetrone