- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Lipid-wrapped Upconversion Nanoconstruct /Photosensitizer Complex for Near-Infrared Light-mediated Photodynamic Therapy
摘要： Photodynamic therapy (PDT) is a non-invasive medical technology that has been applied in cancer treatment where it is accessible by direct or endoscope-assisted light irradiation. To lower phototoxicity and increase tissue penetration depth of light, great effort has been focused on developing new sensitizers that can utilize red or near-infrared (NIR) light for the past decades. Lanthanide-doped upconversion nanoparticles (UCNPs) have a unique property to transduce NIR excitation light to UV-Vis emission efficiently. This property allows some low-cost, low-toxicity, visible light commercially available sensitizers, which originally is not suitable for deep tissue PDT, to be activated by NIR light, and has been reported extensively in the past few year. However, some issues still remain in UCNP-assisted PDT platform such as colloidal stability, photosensitizer loading efficiency, and accessibility for targeting ligand installation, despite some advances in this direction. In this study, we designed a facile phospholipids-coated UCNP method to generate a high-colloidally stable nanoplatform that can effectively load a series of visible light sensitizers in the lipid layers. The loading stability and singlet oxygen generation efficiency of these sensitizers loaded lipid-coated UCNP platform were investigated. We also have demonstrated the enhanced cellular uptake efficiency and tumor cell selectivity of this lipid-coated UCNP platform by changing the lipid dopant. On the basis of the evidence of our results, the lipid-complexed UCNP nanoparticles could serve as an effective photosensitizers carrier for NIR light mediated PDT.
关键词： phospholipids,upconversion,photosensitizers,photodynamic therapy,bioimaging
更新于2025-09-23 15:21:21
-
Upconversion luminescence properties of Y2O3: Yb3+/Er3+/Tm3+ nanocrystal doped PMMA nanocomposites
摘要： Y2O3 nanocrystals triply doped with Yb3+, Er3+, Tm3+ ions were synthesized via alginic acid-assisted gelation using thermal decomposition method and annealed at 800 °C for 24 h. Nanopowders were embedded into PMMA matrix via free-radical polymerization in an ultrasonic bath. X-ray diffraction and transmission electron microscopy measurements have shown that the crystal grain sizes decreased significantly with the narrow size distributions of the nanocrystals in PMMA matrix. A diode laser at 975 nm was used to measure the upconversion luminescence of the annealed nanopowders and those embedded in PMMA between the 400–850 nm wavelength region. The Er3+ concentration and the excitation power density dependencies of the relative intensities for red, green and blue upconversion luminescence in the nanopowder and PMMA nanocomposites are found to be different. The measured CIE-1931 color coordinates of the upconversion luminescence in PMMA nanocomposites show appreciable color stability under different excitation power densities, which is required for potential applications in the field of photonics.
关键词： Color Tunable Emission,Upconversion Luminescence,Polymer nanocomposites,Color Stability,Polymethyl methacrylate (PMMA)
更新于2025-09-23 15:21:21
-
Synthesis and Luminescence Properties of Nanostructured Gd3 –x – yYbxEryBWO9 Borate Tungstates
摘要： Using the Pechini process in the presence of citric acid and mannitol, followed by annealing in the range 800–1000°C, we have synthesized nanostructured rare-earth borate tungstates crystallizing in hexagonal symmetry (sp. gr. P63): undoped Gd3BWO9 and Gd3 – x – yYbxEryBWO9, containing Yb3+ and Er3+ active ions. We have measured upconversion luminescence spectra of the Er3+ ions in Gd3 – x – yYbxEryBWO9 for the 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions under excitation by an IR laser (λ = 974 nm). The spectra consist of two groups of broadened bands in the red and green spectral regions. Brighter luminescence is observed in the green spectral region, which contains two bands corresponding to the Er3+ 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions. We have analyzed the effect of annealing temperature on the upconversion luminescence intensity of Gd3 – x – yYbxEryBWO9 and determined the energy yield of upconversion luminescence in the Gd3 – x – yYbxEryBWO9 borate tungstates. The highest value, Ben = 0.19%, has been obtained for the phosphor with Yb : Er = 7 : 1.
关键词： nanophosphors,rare-earth borate tungstates,upconversion phosphors
更新于2025-09-23 15:21:21
-
Characteristics of Upconversion Luminescence of CaF2:Er Powders Excited by 1.5-?μm Laser Radiation
摘要： The characteristics of upconversion luminescence of CaF2:Er crystalline powders upon laser excitation of Er3+ ions to the 4I13/2 level at a wavelength of 1531.8 nm are studied. The upconversion luminescence energy yields for the spectral regions of 380–780 and 380–1100 nm are determined. It is found that upconversion luminescence of CaF2:Er powders with Er3+ concentrations of 0.5, 2, 4, 6, 8, 10, 11, 13, 15, and 17% is characterized by correlated color temperatures of 5100, 2142, 1726, 1738, 1773, 1757, 1762, 1765, 1735, and 1714 K, respectively.
关键词： luminescence,crystalline powders,upconversion
更新于2025-09-23 15:21:01
-
Solution-processed upconversion photodetectors based on quantum dots
摘要： Upconversion photodetectors convert photons from the infrared to the visible light spectrum and are of use in applications such as infrared detection and imaging. High-performance upconversion devices are, however, typically based on vacuum-deposited materials, which are expensive and require high operating voltages, which limits their implementation in flexible systems. Here we report solution-processed optical upconversion photodetectors with a high photon-to-photon conversion efficiency of 6.5% and a low turn-on voltage of 2.5 V. Our devices consist of a colloidal lead sulfide quantum dot layer for harvesting infrared light that is monolithically coupled to a cadmium selenide/zinc selenide quantum dot layer for visible-light emission. We optimized the charge-extraction layers in these devices by incorporating silver nanoparticles into the electron transport layers to enable carrier tunnelling. Our photodetectors exhibit a low dark current, high detectivity (6.4 × 1012 Jones) and millisecond response time, and are compatible with flexible substrates. We also show that the devices can be used for in vitro bioimaging.
关键词： quantum dots,infrared detection,bioimaging,flexible electronics,upconversion photodetectors
更新于2025-09-23 15:21:01
-
Color tunable upconversion luminescence and optical thermometry properties of mixed Gd2O3:Yb3+/Ho3+/Er3+ nanoparticles prepared via laser ablation in liquid
摘要： The mixtures of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles were successfully prepared via pulsed laser ablation in liquid followed by solution mixing. Under excitation of 980 nm diode laser, tunable color from green to red emission was achieved. Based on the thermal linked energy levels, the temperature sensitive upconversion emission was observed. The fluorescence intensity ratio (FIR) of I513–530 nm/I530–580 nm increased as the elevation of temperature. The absolute sensitivity and relative sensitivity were derived from temperature dependent FIR. The results show that the mixture of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles are not only potential candidates for multicolor upconversion luminescence but also promising optical materials for non-contact optical thermometry.
关键词： Gd2O3 nanoparticles,Color tunable emission,Pulsed laser ablation in liquid,Optical thermometry,Upconversion luminescence
更新于2025-09-23 15:21:01
-
Local Overheating of Biotissue Labeled With Upconversion Nanoparticles Under Yb3+ Resonance Excitation
摘要： Local overheating of biotissue is a critical step for biomedical applications, such as photothermal therapy, enhancement of vascular permeability, remote control of drug release, and so on. Overheating of biological tissue when exposed to light is usually realized by utilizing the materials with a high-absorption cross section (gold, silica, carbon nanoparticles, etc.). Here, we demonstrate core/shell NaYF4:Yb3+, Tm3+/NaYF4 upconversion nanoparticles (UCNPs) commonly used for bioimaging as promising near-infrared (NIR) absorbers for local overheating of biotissue. We assume that achievable temperature of tissue labeled with nanoparticles is high enough because of Yb3+ resonance absorption of NIR radiation, whereas the use of auxiliary light-absorbing materials or shells is optional for photothermal therapy. For this purpose, a computational model of tissue heating based on the energy balance equations was developed and verified with the experimentally obtained thermal-graphic maps of a mouse in response to the 975-nm laser irradiation. Labeling of biotissue with UCNPs was found to increase the local temperature up to 2?C compared to that of the non-labeled area under the laser intensity lower than 1 W/cm2. The cellular response to the UCNP-initiated hyperthermia at subcritical ablation temperatures (lower than 42?C) was demonstrated by measuring the heat shock protein overexpression. This indicates that the absorption cross section of Yb3+ in UCNPs is relatively large, and microscopic temperature of nanoparticles exceeds the integral tissue temperature. In summary, a new approach based on the use of UCNP without any additional NIR absorbers was used to demonstrate a simple approach in the development of photoluminescent probes for simultaneous bioimaging and local hyperthermia.
关键词： near-infrared irradiation,local overheating,photothermal material,bioimaging,heat shock proteins,biotissue laser heating,hyperthermia,upconversion nanoparticles
更新于2025-09-23 15:21:01
-
An ultrasensitive homogeneous aptasensor for carcinoembryonic antigen based on upconversion fluorescence resonance energy transfer
摘要： Carcinoembryonic antigen (CEA) has been recognized as one of the most important tumor markers. Herein, we reported an ultrasensitive homogeneous aptasensor based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) and graphene oxide (GO) for CEA detection. The CEA aptamer modified UCNPs can bind to the surface of GO through π-π stacking interaction, resulting in fluorescence quenching due to the energy transfer from UCNPs to GO. After the introduction of CEA, the CEA aptamer preferentially combined with CEA to form three-dimensional structure which made UCNPs-aptamer dissociate from the GO, blocking the energy transfer process. The fluorescence of UCNPs was accordingly restored in a CEA concentration-dependent manner both aqueous solution and human serum samples. The aptasensor could monitor CEA level directly in human serum and the results were strongly correlated with commercial chemiluminescence kits. The excellent detection performance suggested promising prospect of the aptasensor in practical application.
关键词： Upconversion Nanoparticles,Graphene Oxide,Fluorescence Resonance Energy Transfer,CEA,Aptasensor
更新于2025-09-23 15:21:01
-
Evolution of Size and Optical Properties of Upconverting Nanoparticles during High Temperature Synthesis
摘要： We investigated the growth of β-phase NaYF4:Yb3+,Er3+ upconversion nanoparticles synthesized by the thermal decomposition method using a combination of in situ and offline analytical methods for determining the application-relevant optical properties, size, crystal phase, and chemical composition. This included in situ steady state luminescence in combination with offline time-resolved luminescence spectroscopy, as well as small-angle X-ray scattering (SAXS) transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and inductively coupled plasma optical emission spectrometry (ICP-OES). For assessing the suitability of our optical monitoring approach, the in situ collected spectroscopic data, that reveal the luminescence evolution during nanocrystal synthesis, were compared to measurements done after cooling of the reaction mixture of the as-synthesized particles. The excellent correlation of the in situ and time-resolved upconversion luminescence with the nanoparticle sizes determined during the course of the reaction provides important insights into the various stages of nanoparticle growth. This study highlights the capability of in situ luminescence monitoring to control the efficiency of UCNP synthesis, particularly the reaction times at elevated temperatures and the particle quality in terms of size, shape and crystall structure, as well as luminescence lifetime and upconversion quantum yield.
关键词： thermal decomposition,XRD,ICP-OES,TEM,in situ luminescence,SAXS,upconversion nanoparticles
更新于2025-09-23 15:21:01
-
pH Mediated Control Synthesis of Lanthanide-Doped YPO4 Upconversion Nano/Microcrystals
摘要： A pH-mediated rational control over the phase transformation, morphology and size of lanthanide doped YPO4 nano/microcrystals has been accomplished using a hydrothermal route. The morphology of the resulting particles evolves from the spheres, to the nanoflakes and finally to the nanorods when increasing the pH value of the reaction solution from 1 to 9, while the induction of crystal phase transformation from a tetragonal structure to a hexagonal structure takes place at pH = 5. When excited at 980 nm, the hexagonal phase YPO4?0.8H2O: 18%Yb3+, 2%Er3+ nanoflakes prepared at pH = 7 exhibit the strongest UC emission intensity among investigated samples of varying size, phase and morphologies. This work provides a paradigm on the controlled synthesis of lanthanide doped upconverting orthophosphates, which hold great promise for various photonic and biophotonic applications.
关键词： Orthophosphate,Morphology,Upconversion
更新于2025-09-23 15:21:01