Hybrid Nanostructures for High‐Sensitivity Luminescence Nanothermometry in the Second Biological Window

Abstract

Hybrid nanostructures containing neodymium-doped nanoparticles and infrared-emitting quantum dots constitute highly sensitive luminescent thermometers operating in the second biological window. They demonstrate that accurate subtissue fluorescence thermal sensing is possible.

Boosting the sensitivity of Nd3+-based luminescent nanothermometers

“…The maximum relative sensitivity value of 1.75 ± 0.04% K −1 attained at 288 K is, to the best of our knowledge, the highest reported (by one order of magnitude) for the physiological range for luminescent Nd 3+ -based thermometers ( Table 1). 26 For instance, the value presented here is comparable with the maximum S r value of CaF 2 :Tm 3+ , Yb 3+ nanoparticles, around 2% K −1 at 299 K. 36 We should emphasize, however, that the comparison presented in Fig. 4A) were not corrected for the detector response, the calculated sensitivity values are somehow convoluted by that response.…”

“…In particular, because Nd 3+ has a ladder-like intra-4f energy-level structure the excitation and emission lie within the first biological window (700-980 nm) where the transparency of living tissues is high due to low optical absorption, offering much potential for deep-tissue luminescence imaging 25 and temperature sensing. 26) is not discussed here as the Nd 3+ emission at 1060 nm is temperature independent. 25 The recent example by Jaque's group combining NaGdF 4 :Nd 3+ nanoparticles and PbS/CdS/ZnS quantum dots in a single-encapsulated organic-inorganic hybrid nanostructure operating in the second biological window (1000-1350 nm) between 283 and 328 K (ref.…”

Revisiting the classification of NIR-absorbing/emitting nanomaterials for in vivo bioapplications

“…163 This is especially true for NPs where both the sensitizer and activator ions are susceptible to surface quenching. 164 Fortunately, lanthanide materials also have valuable Stokes emissions in the NIR spectral regions (Figures 12a-c), 165 which have been used for imaging in the NIR biological transmission window NIR, 166,167 in intentional light-to-heat and heat-totemperature [168][169][170][171] readout features in single (Figure 12d) or hybrid NP-based 'devices'. There are numerous comprehensive review articles of the physics, spectroscopy and biomedical applications or nanotoxicity of lanthanide-doped NPs, and thus the readers are referred to these articles for further information.…”

Nd 3+ ions in nanomedicine: Perspectives and applications

“…In this respect, Nd 3þ ions can play also a relevant role. In fact, E. Navarro Cer on et al have recently synthesized hybrid nanostructures of about 100 nm containing Nd 3þ :NaGF 4 NPs together with PbS/CdS/ZnS quantum dots, both encapsulated in a single polymeric matrix (PLGA) [84]. In these hybrid nanostructures, the 1060 nm emission intensity of Nd 3þ is used as a temperature insensitive reporter while that of the quantum dots (at about 1270 nm) is strongly quenched in the physiological range.…”