Temperature Sensing of Deep Abdominal Region in Mice by Using Over-1000 nm Near-Infrared Luminescence of Rare-Earth-Doped NaYF4 Nanothermometer

Abstract

Luminescence nanothermometry has attracted much attention as a non-contact thermal sensing technique. However, it is not widely explored for in vivo applications owing to the low transparency of tissues for the light to be used. In this study, we performed biological temperature sensing in deep tissues using β-NaYF4 nanoparticles co-doped with Yb3+, Ho3+, and Er3+ (NaYF4: Yb3+, Ho3+, Er3+ NPs), which displayed two emission peaks at 1150 nm (Ho3+) and 1550 nm (Er3+) in the >1000 nm near-infrared wavelength region, where the scattering and absorption of light by biological tissues are at the minimum. The change in the luminescence intensity ratio of the emission peaks of Ho3+ and Er3+ (IHo/IEr) in the NaYF4: Yb3+, Ho3+, Er3+ nanothermometer differs corresponding to the thickness of the tissue. Therefore, the relationship between IHo/IEr ratio and temperature needs to be calibrated by the depth of the nanothermometer. The temperature-dependent change in the IHo/IEr was evident at the peritoneal cavity level, which is deeper than the subcutaneous tissue level. The designed experimental system for temperature imaging will open the window to novel luminescent nanothermometers for in vivo deep tissue temperature sensing.

Luminescence Nanothermometry Based on Pr3+ : LaF3 Single Core and Pr3+ : LaF3/LaF3 Core/Shell Nanoparticles

“…It should be noted that the CSR is not a physical size of the NPs. e following Debye-Scherrer formula is used [24]:…”

“…Indeed, over the past decade, interest in nanothermometry based on rare-earth-doped fluoride nanoparticles has increased significantly [22][23][24][25]. On the one hand, nanosized dimensionality of the luminescent nanothermometers allows them to come into contact with the studied small system providing accurate and precise temperature measurement [16].…”

NIR‐II/III Luminescence Ratiometric Nanothermometry with Phonon‐Tuned Sensitivity

“…In addition, the active‐core/active‐shell Nd 3+ ‐ and Yb 3+ ‐codoped LaF 3 nanoparticles have been utilized for subcutaneous thermal relaxation monitoring with excitation at 808 nm and a ratiometric temperature readout in NIR‐II window . Despite recent advances, NIR lanthanide thermal probes with high sensitivity remain elusive, in particular, in NIR‐II and/or NIR‐III windows that have higher penetration depth and null autofluorescence from endogenous pigmentations …”

Fluorescent Polystyrene Latex Nanoparticles for NIR-II <i>in vivo</i> Imaging

“…Therefore, the NIR-II and NIR-III regions are the most ideal wavelength regions for fluorescence bioimaging. In the past decade, our group reported on NIR-II and NIR-III fluorescence imaging based on various probes such as rare-earth doped ceramic nanoparticles (RED-CNPs) [6][7][8][9][10][11], single-walled carbon nanotubes (SWCNTs) [12], and organic dyes [13]. These fluorescent probes showed excellent fluorescence properties, and could be used for successful imaging of deep tissues (10 -20 mm).…”