Real-time deep-tissue thermal sensing with sub-degree resolution by thermally improved Nd3+:LaF3 multifunctional nanoparticles

Rocha, Uéslen; Jacinto, Carlos; Kumar, K. Upendra; López, Fernando; Bravo, D.; Solé, J. Garcı́a; Jaque, Daniel

doi:10.1016/j.jlumin.2016.02.034

Cited by 71 publications

(37 citation statements)

References 51 publications

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“…As an alternative, the lanthanide ion Nd 3+ (4f 3 ) has become a promising candidate for in vivo nanothermometry [30,[38][39][40][41][42][43]. This is related to the fact that its most intense radiative transitions all lie within BW I and BW II.…”

Section: Introductionmentioning

confidence: 99%

Making Nd3+ a Sensitive Luminescent Thermometer for Physiological Temperatures—An Account of Pitfalls in Boltzmann Thermometry

et al. 2020

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Ratiometric luminescence thermometry employing luminescence within the biological transparency windows provides high potential for biothermal imaging. Nd3+ is a promising candidate for that purpose due to its intense radiative transitions within biological windows (BWs) I and II and the simultaneous efficient excitability within BW I. This makes Nd3+ almost unique among all lanthanides. Typically, emission from the two 4F3/2 crystal field levels is used for thermometry but the small ~100 cm−1 energy separation limits the sensitivity. A higher sensitivity for physiological temperatures is possible using the luminescence intensity ratio (LIR) of the emissive transitions from the 4F5/2 and 4F3/2 excited spin-orbit levels. Herein, we demonstrate and discuss various pitfalls that can occur in Boltzmann thermometry if this particular LIR is used for physiological temperature sensing. Both microcrystalline, dilute (0.1%) Nd3+-doped LaPO4 and LaPO4: x% Nd3+ (x = 2, 5, 10, 25, 100) nanocrystals serve as an illustrative example. Besides structural and optical characterization of those luminescent thermometers, the impact and consequences of the Nd3+ concentration on their luminescence and performance as Boltzmann-based thermometers are analyzed. For low Nd3+ concentrations, Boltzmann equilibrium starts just around 300 K. At higher Nd3+ concentrations, cross-relaxation processes enhance the decay rates of the 4F3/2 and 4F5/2 levels making the decay faster than the equilibration rates between the levels. It is shown that the onset of the useful temperature sensing range shifts to higher temperatures, even above ~ 450 K for Nd concentrations over 5%. A microscopic explanation for pitfalls in Boltzmann thermometry with Nd3+ is finally given and guidelines for the usability of this lanthanide ion in the field of physiological temperature sensing are elaborated. Insight in competition between thermal coupling through non-radiative transitions and population decay through cross-relaxation of the 4F5/2 and 4F3/2 spin-orbit levels of Nd3+ makes it possible to tailor the thermometric performance of Nd3+ to enable physiological temperature sensing.

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Section: Introductionmentioning

confidence: 99%

Making Nd3+ a Sensitive Luminescent Thermometer for Physiological Temperatures—An Account of Pitfalls in Boltzmann Thermometry

et al. 2020

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“…The g 3 resonance is not observed and both g 1 and g 2 ‐lines become broader increasing the Nd 3+ content due to stronger spin‐spin relaxation process. Similar results were obtained by U. Rocha et alstudying LaF 3 nanoparticles (NPs) doped with different amount of Nd 3+ . Only for low concentrations such as 0.2 mol% the three g resonances were observed together with the hyperfine structure of g 1 ‐line.…”

Section: Resultsmentioning

confidence: 55%

Effect of dopant precursors on the optical properties of rare‐earths doped oxyfluoride glass‐ceramics

et al. 2019

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The crystallization of fluoride nanocrystals (NCs) in chemically and mechanically stable aluminosilicate glasses has shown interesting optical properties even for small crystal fractions (10‐15 wt%). When rare‐earth (RE) ions are used as dopants, crystal‐like features can be reproduced and an increase in the emission and/or energy transfer processes, with respect to the starting glasses, is observed. A crucial point for these materials is the study of the local surrounding of RE ions and their incorporation in the NCs. In fact, the effective concentration in the NCs can be much higher than the nominal concentration, up to one order of magnitude or even higher. The knowledge of RE ions incorporation in the NCs permits choosing proper doping levels to optimize both linear and nonlinear optical properties. In this work, transparent oxyfluoride glass‐ceramics with LaF3 NCs, doped with Nd3+ and Er3+ using oxide and fluoride precursors, were prepared using the melt‐quenching method and controlled crystallization. The local surrounding of the RE ions was studied using X‐ray absorption spectroscopy, electron paramagnetic resonance and photoluminiscence. The results show that most RE ions are already in a fluorine‐rich amorphous environment even in the initial glass. The crystallization process provokes the RE ion redistribution and incorporation in the fluoride NCs. The different RE precursors, used as oxides or fluorides, have an influence on the incorporation of the RE in the NCs and, as a consequence, on the final optical properties.

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“…U. Rocha et al have recently demonstrated how both a decrease in the doping level as well as an appropriate thermal annealing of LaF 3 :Nd 3þ NPs considerably increase the thermal sensitivity in the 4 F 3/2 / 4 I 9/2 emission of these nanothermometers [67]. To illustrate the Fig.…”

Section: Nd As Fluorescence Sensor Nd 3þ Ion Based Nanothermometersmentioning

confidence: 96%

“…8 (b)), is shown to increase by a factor close to 4 with respect to the non-annealed ones. By using this strategy for improving thermal sensitivity, the authors achieved a sub-tissue thermal resolution as low as 0.7 C [67]. At this point, it is interesting to note how the spectral width of Nd 3þ emission lines provides an indirect information on the lattice ordering and on the particle size too.…”

Section: Nd As Fluorescence Sensor Nd 3þ Ion Based Nanothermometersmentioning

confidence: 99%

“…(a) Room temperature 4 F 3/2 / 4 I 9/2 emission spectrum of LaF 3 :Nd 3þ (5.6%) NPs before (asesynthesized) and after a thermal annealing of these nanoparticles at 500 C, after ref. [67]. (b) Intensity ratio between the two peaks marked in Figure (a) as a function of temperature for as-synthesized (squares) and annealed at 500 C (dots) LaF 3 :Nd 3þ (5.6%) NPs.…”

Section: Nd As Fluorescence Sensor Nd 3þ Ion Based Nanothermometersmentioning

confidence: 99%

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Nd 3+ ions in nanomedicine: Perspectives and applications

et al. 2017

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Real-time deep-tissue thermal sensing with sub-degree resolution by thermally improved Nd3+:LaF3 multifunctional nanoparticles

Cited by 71 publications

References 51 publications

Making Nd3+ a Sensitive Luminescent Thermometer for Physiological Temperatures—An Account of Pitfalls in Boltzmann Thermometry

Making Nd3+ a Sensitive Luminescent Thermometer for Physiological Temperatures—An Account of Pitfalls in Boltzmann Thermometry

Effect of dopant precursors on the optical properties of rare‐earths doped oxyfluoride glass‐ceramics

Nd 3+ ions in nanomedicine: Perspectives and applications

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