Emitter-Active Shell in NaYF₄:Yb,Er/NaYF₄:Er Upconversion Nanoparticles for Enhanced Energy Transfer in Photodynamic Therapy

Abstract

To realize the potential of near-infrared (NIR) upconversion nanosensitizers for photodynamic therapy of cancer, upconversion luminescence and energy transfer (ET) efficiency from emitter donors to photosensitizer acceptors need to be improved. In the current work, upconversion nanoparticles (UCNPs) with a core/emitter-active shell structure were constructed to enhance not only the upconversion emission but also the ET from the nanoparticles to surface-anchored photosensitizers. The emitter was doped into the shell to bridge the migration of upconverted energy to the surface. NaYF4:Yb,Er/NaYF4:Er UCNPs and rose bengal (RB) photosensitizer were employed as an example. The upconversion emission was lifted by up to ∼81 times of the core counterpart. The bridge effect of the emitter-doped shell was obvious for the constructed nanophotosensitizer. The emission of the RB photosensitizer was up to ∼36 times that of the core counterpart. The NaYF4:Yb,Er/NaYF4:Er UCNPs also endow the RB photosensitizers with the most efficient reactive oxygen species production capability under NIR irradiation. In vitro photodynamic tests on glioma cells were conducted to validate the efficacy of the NaYF4:Yb,Er/NaYF4:Er/RB agent. Therefore, this work can facilitate the development of ET-based upconversion nanosystems.

Ruthenium-Based Photoactivated Chemotherapy

“…It should be noted that divergent beams from extremely powerful lasers (e.g., 5–15 W) can also be used to irradiate 96-well plates. Such setups allow for reaching much higher light intensities in vitro (e.g., 700 mW/cm 2 ), which may be used to activate compounds with low photosubstitution quantum yields …”

“…Such setups allow for reaching much higher light intensities in vitro (e.g., 700 mW/cm 2 ), which may be used to activate compounds with low photosubstitution quantum yields. 96 In vivo, the irradiation time depends on the animal model. In mice or rats, the animal should not move during irradiation, so in most PDT or PACT studies it is anesthetized during light irradiation.…”

Near-infrared-driven upconversion nanoparticles with photocatalysts through water-splitting towards cancer treatment

“…86 UCNPs can convert NIR light into UV light, and TiO 2 can be activated to produce ROS. 87 Thus, UCNP-based photosensitive materials can enhance PDT efficacy and penetrate deep tissue. 88 Therefore, Nd 3+ ion-doped UCNPs can be utilized as extreme sensitizers via energy migration during the upconversion process.…”

High-intensity first near-infrared emission through energy migration in multilayered upconversion nanoparticles

“…Lanthanide-based upconversion nanoparticles (UCNPs), capable of converting low energy photons (typically 808, 980 and 1532 nm) to high-energy visible and ultraviolet emissions, have great application value in super-resolution nanoscopy, solar cells, photodynamic therapy, anti-counterfeiting, biomedical imaging and other fields. [1][2][3][4][5][6][7][8][9][10][11] In particular, UCNPs have unique advantages in biomedical imaging due to their large anti-Stokes shift, high sensitivity, low toxicity, and deep penetration. [12][13][14][15] In the past decades, visible light (400-700 nm) and first nearinfrared (NIR-I, 700-1000 nm) biomedical imaging was widely studied.…”