Rare-earth-based upconversion nanotechnology has recently shown great promise for photodynamic therapy (PDT). However, the NIR-induced PDT is greatly restricted by overheating issues on normal bodies and low yields of reactive oxygen species (ROS, O). Here, IR-808-sensitized upconversion nanoparticles (NaGdF:Yb,Er@NaGdF:Nd,Yb) were combined with mesoporous silica, which has Ce6 (red-light-excited photosensitizer) and MC540 (green-light-excited photosensitizer) loaded inside through covalent bond and electrostatic interaction, respectively. When irradiated by tissue-penetrable 808 nm light, the IR-808 greatly absorb 808 nm photons and then emit a broadband peak which overlaps perfectly with the absorption of Nd and Yb. Thereafter, the Nd/Yb incorporated shell synergistically captures the emitted NIR photons to illuminate NaGdF:Yb,Er zone and then radiate ultrabright green and red emissions. The visible emissions simultaneously activate the dual-photosensitizer to produce a large amount of ROS and, importantly, low heating effects. The in vitro and in vivo experiments indicate that the dual-photosensitizer nanostructure has trimodal (UCL/CT/MRI) imaging functions and high anticancer effectiveness, suggesting its potential clinical application as an imaging-guided PDT technique.

AgBiS2 nanodots as an NIR light-excited photosensitizer produce a PDT effect, which is reported for the first time.

Rare-earth-doped up-conversion nanoparticles (UCNPs), which are capable of converting infrared light to shorter-wavelength photons, have attracted worldwide attention due to their unique characteristics. However, the emission brightness of UCNPs is greatly limited by the unsatisfactory absorptivity of lanthanide ions. Herein, we adopted a novel strategy to enhance the up-conversion intensity using NIR dye IR-808 as an antenna to sensitize the core-shell-shell structured NaGdF:Yb,Er@NaGdF:Yb@NaNdF:Yb UCNPs. When excited with 808 nm light, the IR-808 emitted a broadband peak, which perfectly overlapped with the absorption of Nd and Yb ions. Thus, the active shell of NaNdF:Yb can efficiently capture the emitted NIR photons and transfer them to the transition layer of NaGdF:Yb. The transition layer acted as an energy bridge to connect the active shell and up-converting zone, avoiding the energy back-transfer from the activators to Nd ions. The optimized dye sensitization combined with the well-designed core-shell-shell structure tremendously enhances the NIR photon absorptivity of UCNPs and eliminates the deleterious cross-relaxation between the activators and sensitizers, eventually leading to dramatic enhancement of the up-conversion intensity. This study provides a new insight into the dye-sensitized up-conversion luminescence of rare earth-based nanoparticles and facilitates their practical applications.

In Saccharomyces cerevisiae, the mitochondrial nicotinamide adenine dinucleotide hydride kinase Pos5p is required for a variety of essential cellular pathways, most importantly respiration. The Pos5p knockout strain pos5D grows poorly in non-fermentable media. A potential relationship between this respiratory deficiency and the ability of the cells to supply nicotinamide adenine dinucleotide phosphate (NADPH) was examined by analyzing the respiratory chain activity of pos5D and two NADP 1 -specific dehydrogenase mutants, idp1D and zwf1D. All of the respiratory chain complexes of pos5D exhibited poor relative activity of <26% at the middle-log phase and 62% at the stationary phase. The respiratory chain activity levels of idp1D and zwf1D also reduced to 22% -37% and 28%-84% at the middle-log phase, and 73% -81% and 67% -88% at the stationary phase, not as robustly as those of pos5D. The double-mutant idp1pos5D exhibited even lower activities of <20% at the middle-log phase, but zwf1pos5D showed similar activities with pos5D. The complemented strain POS5/pos5D exhibited 1.05-to 3-fold higher activities than pos5D. These data showed that Pos5p contributes to the maintenance of respiratory chain complex activities, with other NADPH sources, such as Idp1p and Zwf1p, making a smaller contribution. These contributions were partly related to the ability of the cells to supply NADPH, especially in the mitochondria.

Photodynamic therapy (PDT) and photothermal therapy (PTT) are well-developing light therapy methods for cancer at present. Nevertheless, both of them have a few parts for improvement. Firstly, sustained PDT effect...

Photodynamic therapy (PDT) is a light-based modality for tumor treatment that involves the generation of reactive oxygen species (ROS) by the combination of light, a photosensitizer, and molecular oxygen.

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We theoretically and numerically demonstrate optimal design of wavelength selective thermal emitter using one-dimensional (1D) and two-dimensional (2D) metal-dielectric gratings for thermophotovoltaic (TPV) applications. Proposed design consists of tungsten (W) and silicon dioxide (SiO) gratings which can withstand high temperatures. Radiative properties of 1D grating were calculated using a numerical method, while effective medium approximation was used for 2D gratings. Optimal designs were obtained such that output power is maximum for GaSb photovoltaic (PV) cell at emitter temperature of 1500 K and radiated energy for longer wavelengths is limited to a low value. A constrained optimization was performed using genetic algorithm (GA) to arrive at optimal design.