Sub-10 nm NaNdF₄ Nanoparticles as Near-Infrared Photothermal Probes with Self-Temperature Feedback

Abstract

Photothermal therapy (PTT) has been widely used for the treatment of various medical conditions due to their noninvasive and cost-effective advantages. However, the light absorption and scattering of the biosystem limit the deep tissue applications of conventional PTT probes. In this paper, we proposed the sub-10 nm NaNdF 4 nanocrystals with both incident and emission wavelengths located at the optical window. Under 800 nm laser excitation, the maximum light-to-heat conversion efficiency of these ultrasmall photothermal agents is evaluated to be 85%. In addition, the conversion efficiency can be further adjusted through varying the doping concentration, changing the probe size, and coating the inert shell. Meanwhile, temperature feedback on the basis of the Nd 3+ luminescence signal validates the precise temperature manipulating inside the biological tissue, evidencing the feasibility of the proposed probes for PTT treatment. Beneficial from the efficient photothermal conversion and low energy loss of excitation/ emission photons in organic tissue, the effective treatment depth of the nanoprobes goes to 6 mm with the actual laser power density only ∼0.2 W/cm 2 . Finally, based on the rapid heating response of the formed nanoprobes, fast ablation treatment of a 1.5 cm pork tissue is achieved using pulsed laser.

Effect of the Size and Shape of Ho, Tm:KLu(WO4)2 Nanoparticles on Their Self-Assessed Photothermal Properties

“…The photothermal conversion efficiency reported here is of the same order of magnitude than that reported for graphene in DMF [ 37 ] and Au nanoshells or Au nanorods [ 10 ]. However, the ability of Au nanostars [ 10 ], NaNdF 4 [ 72 ], NdVO 4 in water [ 73 ], or core@shell@shell NaNdF 4 @NaYF 4 @Nd:NaYF 4 [ 74 ] to generate heat is still higher compared to the Ho, Tm doped KLuW nanocrystals reported here ( Table 1 ).…”

“…Double Beam Fluorescence Thermometry 808 102 [10] Au nanorods Double Beam Fluorescence Thermometry 808 95 [10] NaNdF4 Thermal Relaxation 800 85 [72] NaNdF4@NaYF4@ Nd:NaYF4 Thermal Relaxation 808 72.7 [74] NdVO4 in water Thermal Relaxation 808 72.1 [73] Au nanoshells Double Beam Fluorescence Thermometry 808 68 [10] Graphene in DMF Integrating Sphere 808 67 [37] Au nanorods Double Beam Fluorescence Thermometry 808 63 [10] Au nanorods Thermal Relaxation 815 61 [71] Au/AuS nanoshells Thermal Relaxation 815 59 [71] Graphene Oxide in water Integrating Sphere 808 58 [37] Ho [29] Au/SiO2 nanoshells Thermal Relaxation 815 34 [71] FePt nanoparticles Pconverted to heat/Pexcitation 800 30 [70] Cu9S5 Thermal Relaxation 980 25.7 [22] Au nanoshells Thermal Relaxation 808 25 [75] 3.6. Ho, Tm:KLuW Nanocrystals as Self-Assessed Photothermal Agents Ho, Tm:KLuW nanocrystals exhibit the ability to self-determine the temperature achieved by the system when releasing heat by using luminescence thermometry, generating self-assessed photothermal agents.…”

Up-Converting Luminescence and Temperature Sensing of Er3+/Tm3+/Yb3+ Co-Doped NaYF4 Phosphors Operating in Visible and the First Biological Window Range

“…Thus, we choose Er 3+ as one of the doped rare earth ions and the green emissions can be used as the detected signal in the visible range for thermometry. However, the green emissions have obvious absorption and limited penetration depth in biological tissues [17,18]. Therefore, the selected emissions shall be located in biological windows when the object is located in biological tissues [18].…”

“…However, the green emissions have obvious absorption and limited penetration depth in biological tissues [17,18]. Therefore, the selected emissions shall be located in biological windows when the object is located in biological tissues [18]. Under 980 nm laser excitation, Tm 3+ can emit red (650 nm) and near-infrared emissions (692 and 800 nm) [19], which can be used as the detected signal in the first biological window (650-1000 nm).…”

Real-time RGB color-tunable upconversion luminescence using a single excitation wavelength

“…However, by using these approaches, upconversion emissions with certain colors were obtained, which might be suitable exclusively for speci c applications. For instance, near infrared (NIR) photons exhibit deep penetration in biological tissues 8 , red light falling in the spectral biological window I (BW-I) is promising for visible imaging 9 , green light is most sensitive to human eyes, and blue and UV light are expected to trigger easily photochemical reactions 10 . Despite of these potential applications, a luminescent material capable of emitting different colors, i.e.…”