Luminescent Yb3+,Er3+-Doped α-La(IO3)3 Nanocrystals for Neuronal Network Bio-Imaging and Nanothermometry

Abstract

Dual-light emitting Yb3+,Er3+-codoped α-La(IO3)3 nanocrystals, known to exhibit both second harmonic signal and photoluminescence (PL), are evaluated as optical nanoprobes and thermal sensors using both conventional microscopes and a more sophisticated micro-PL setup. When loaded in cortical and hippocampal neurons for a few hours at a concentration of 0.01 mg/mL, a visible PL signal arising from the nanocrystals can be clearly detected using an epifluorescent conventional microscope, enabling to localize the nanocrystals along the stained neurons and to record PL variation with temperature of 0.5% K−1. No signal of cytotoxicity, associated with the presence of nanocrystals, is observed during the few hours of the experiment. Alternatively, a micro-PL setup can be used to discriminate the different PL lines. From ratiometric PL measurements, a relative thermal sensitivity of 1.2% K−1 was measured.

Solution‐Based Synthesis Routes for the Preparation of Noncentrosymmetric 0‐D Oxide Nanocrystals with Perovskite and Nonperovskite Structures

“…Interestingly, the as-prepared 40 nm α-La(IO 3 ) 3 nanocrystals (Figure 22b) show a narrow size distribution (±10 nm) while composition can be readily adjusted with the incorporation of Er 3+ /Yb 3+ rare-earth ions thus complementing their inherent nonlinear optical properties with upconversion functionalities and nanothermometry capabilities. [62,234,235]…”

“…This trend in the nanomedicine field led to the preparation of nanoparticles with bimodal and trimodal capabilities thus allowing the use of different imaging techniques combining for instance high resolution (multiphoton microscopy) or high penetration depths (MRI, PET, CT, ultrasound, photoacoustic) [276,277] and the development of theranostic applications. [278] Regarding NCO nanocrystals, such an increase in multifunctionality has recently been demonstrated through simple NCO doping with rare-earth luminescent ions, [62,235,279] advanced modification of their surface composition [66,67,280] (for the ondemand photo-triggered release of chemotherapeutics or for dual multiphoton and MRI contrasts) and the formation of core/shell nanostructures [60] by heterogeneous nucleation.…”

Influence of excitation and detection geometry on optical temperature readouts – reabsorption effects in luminescence thermometry

“…13,14,[17][18][19][20][21] Optical materials doped with Ln 3+ ions are increasingly used in luminescence thermometry. 1,19,[22][23][24][25][26][27][28][29][30][31][32] Accurate temperature monitoring in isolated and dynamic systems often require a remote detection principle. Inaccessible systems (such as the interior of biological tissue, or closed systems under pressure) can be explored by optical thermometry using diverse temperaturedependent (thermometric) properties of Ln 3+ ions and remote detection of light emission.…”

Upconverting nanoparticles as primary thermometers and power sensors

“…Ln 3+ ions work in the spectral ranges where the biological tissue has minimal absorption and negligible autofluorescence, designated as biological imaging windows. Therefore, luminescent thermometers based on Ln 3+doped nanomaterials have been widely employed in intracellular measurements (Debasu et al, 2020;Piñol et al, 2020;Dantelle et al, 2021;Di et al, 2021;Kim et al, 2021;Dos Santos et al, 2022) and tumor temperature mapping during thermal therapies (Jaque et al, 2014;Carrasco et al, 2015;Zhu et al, 2016Zhu et al, , 2018.…”