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- 2019
- Au nanoparticles in water
- Fourier-Zhukovsky thermal model
- Nanomaterials and Technology
- National Institute for Laser, Plasma and Radiation Physics
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Traps distribution in sol-gel synthesized ZnO nanoparticles
摘要： The distribution of shallow traps within the sol-gel synthesized ZnO nanoparticles was investigated using thermoluminescence (TL) experiments in the 10–300 K temperature range. TL measurements presented two overlapped peaks around 110 and 155 K. The experimental technique based on radiating the nanoparticles at different temperatures (Texc.) between 60 and 125 K was carried out to understand the trap distribution characteristics of peaks. It was observed that peak maximum temperature shifted to higher values and activation energy (Et) increased as irradiating temperature was increased. The Et vs. Texc. presented that ZnO nanoparticles have quasi-continuously distributed traps possessing activation energies increasing from 80 to 171 meV.
关键词： Luminescence,Nanoparticles,Defects
更新于2025-11-21 11:18:25
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Structural, optical and photoluminescence studies of sol-gel synthesized pure and iron doped TiO2 photocatalysts
摘要： Pure and Iron doped TiO2 nanoparticles were synthesized using the sol-gel method. These materials were characterized by X-ray diffractometer (XRD), high-resolution transmission electron microscope (HR-TEM), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), UV-Vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared (FTIR), Raman and fluorescence spectrometer. XRD analysis revealed that all the samples were a single phase with anatase nanocrystallite structures. The crystallite size of titania reduced from 9.64 nm to 7 nm with Fe doping. The HRTEM images of the TiO2 and 3% Fe doped TiO2 have revealed that all the particles have a spherical shape with an average particle size of 10 nm and 8 nm respectively. The characteristic peak at 482 cm-1 of the Ti–O bond stretching vibrations can be evidently observed from FTIR analysis. The Raman blue shift was found in the Fe doped TiO2 samples. Fe-doped TiO2 nanoparticles showed a significant red-shift in band edge as compared with pure TiO2 nanoparticles. The redshift of band gap was detected in Fe doped TiO2 nanoparticles. The photoluminescence (PL) emission intensity of Fe doped TiO2 nanoparticles decreases with an increase in Fe doping concentration. The photocatalytic efficiencies of the Fe-doped TiO2 nanoparticles have shown a strong photocatalytic activity (PCA) response. At constant irradiation time, the Fe-doped titania nanoparticles display more catalytic activity compared to undoped TiO2. The photodegradation efficiencies typically decline with an increase in the concentration of Fe+3 doping for the decolorization of methylene blue (MB) under visible light irradiation.
关键词： band gap,Raman modes,photocatalytic activity,TiO2 nanoparticles,methylene blue,PL emission
更新于2025-11-21 11:18:25
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Origin of milky optical features in type IaB diamonds: Dislocations, nano-inclusions, and polycrystalline diamond
摘要： The milky appearance shown by certain type IaB diamonds has been subjected to several recent studies, but the origin of this feature is not fully understood. Here several type IaB diamonds with a milky appearance have been studied by cathodoluminescence (CL), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). CL of several hazy type IaB diamonds shows scattered or orientated micro-sized spots or short linear luminescence features. TEM observation revealed that those spots and linear features are caused by dislocation loops that are likely responsible for the hazy appearance of the host diamonds. It is also shown that type IaB diamonds with a cloudy appearance contain nano-sized inclusions with negative crystals of octahedral shape. Some of these negative crystals contain a precipitate that can be explained by a compressed disordered cubic δ-N2 phase observed by high-resolution TEM. In one of the milky IaB diamonds with platelet defects, polycrystalline areas composed of columnar diamond crystals elongated radially in [110], similar to ballas diamond, were revealed by EBSD. Taking into account these observations, it is suggested that the dislocation loops, nano-sized inclusions (negative crystals) and/or characteristic grain boundaries of the radiating fibrous crystals would be the origins for the milky appearance of the type IaB diamonds studied here. Those results add a complementary explanation that accounts for the milkiness of type IaB diamonds studied before.
关键词： Type IaB diamonds,Nanominerals and Mineral Nanoparticles,milky,voidites,dislocations,polycrystalline diamond
更新于2025-11-21 11:18:25
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Near-infrared upconversion–activated CRISPR-Cas9 system: A remote-controlled gene editing platform
摘要： As an RNA-guided nuclease, CRISPR-Cas9 offers facile and promising solutions to mediate genome modification with respect to versatility and high precision. However, spatiotemporal manipulation of CRISPR-Cas9 delivery remains a daunting challenge for robust effectuation of gene editing both in vitro and in vivo. Here, we designed a near-infrared (NIR) light–responsive nanocarrier of CRISPR-Cas9 for cancer therapeutics based on upconversion nanoparticles (UCNPs). The UCNPs served as “nanotransducers” that can convert NIR light (980 nm) into local ultraviolet light for the cleavage of photosensitive molecules, thereby resulting in on-demand release of CRISPR-Cas9. In addition, by preparing a single guide RNA targeting a tumor gene (polo-like kinase-1), our strategies have successfully inhibited the proliferation of tumor cell via NIR light–activated gene editing both in vitro and in vivo. Overall, this exogenously controlled method presents enormous potential for targeted gene editing in deep tissues and treatment of a myriad of diseases.
关键词： cancer therapeutics,upconversion nanoparticles,gene editing,CRISPR-Cas9,near-infrared
更新于2025-11-21 11:08:12
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Hyaluronic acid functionalized nanoparticles loaded with IR780 and DOX for cancer chemo-photothermal therapy
摘要： IR780 is a near infrared (NIR) dye with a huge potential to be applied in cancer phototherapy and imaging. However, IR780 poor water solubility and acute cytotoxicity limit its direct use in cancer theragnostic. Herein, a novel Hyaluronic acid (HA)-based amphiphilic polymer was used, for the first time, in the preparation of polymeric nanoparticles (HPN) encapsulating IR780 aimed to be applied in breast cancer therapy. Furthermore, HPN co-encapsulating IR780 and Doxorubicin (DOX) were also produced in order to further enhance the therapeutic effectiveness of this nanoformulation. The results revealed that HPN were able to successfully encapsulate IR780 (IR-HPN) and the IR780-DOX combination (IR/DOX-HPN). Furthermore, the encapsulation of IR780 in HPN improved its absorption at 808 nm by about 2.2-fold, thereby enhancing its photothermal potential, as well as its cytocompatibility. The 2D in vitro cell uptake studies demonstrated that the nanostructures displayed a higher internalization by breast cancer cells than by normal cells. In addition, the assays performed in 3D in vitro models of breast cancer revealed that HPN can penetrate into spheroids. Furthermore, the 3D in vitro studies also demonstrated that the combined application of IR-HPN and NIR light was unable to induce cytotoxicity on spheroids. In contrast, IR/DOX-HPN produced a decrease on spheroids cells’ viability, and their combination with NIR light induced an even stronger therapeutic effect, thus revealing the potential of these nanoparticles for cancer chemo-phototherapy.
关键词： Cancer,Polymeric Nanoparticles,Chemotherapy,IR780,Photothermal therapy,Doxorubicin
更新于2025-11-21 11:08:12
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Luminescent Mesoporous Silica Nanohybrid Based on Drug Derivative Terbium Complex
摘要： Mesoporous silica nanoparticles prepared by organic template-driven synthesis have been successfully explored as carriers of the drug-derivate green luminescent complex of terbium (III) with the nonsteroidal anti-inflammatory drug ketoprofen. The terbium (III) complex was synthesized by reacting ketoprofen sodium salt with terbium (III) chloride, which was further adsorbed onto the surface of mesoporous nanoparticles with a mean particle size of 47 ± 4 nm and pore size of 11 nm. The incorporation of the complex into mesoporous silica nanoparticles was tracked by the decrease in the surface area and pore size of the nanoparticles, and successfully demonstrated by substantial changes in the adsorption isotherms and thermal and vibrational spectroscopy results. The cytotoxicity assay and confocal microscopy have shown that the novel luminescent nanohybrid presents high cell viability and the characteristic terbium (III) emission can be assessed through two-photon excitation, which paves the way for bioimaging applications in nanomedicine.
关键词： ketoprofen,mesoporous silica nanoparticles,terbium,luminescent nanohybrid,two-photon
更新于2025-11-21 11:08:12
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Preclinical Study of Biofunctional Polymer-Coated Upconversion Nanoparticles
摘要： Upconversion nanoparticles (UCNPs) are new-generation photoluminescent nanomaterials gaining considerable recognition in the life sciences due to their unique optical properties that allow high-contrast imaging in cells and tissues. UCNP applications in optical diagnosis, bioassays, therapeutics, photodynamic therapy, drug delivery, and light-controlled release of drugs are promising, demanding a comprehensive systematic study of their pharmacological properties. We report on production of biofunctional UCNP-based nanocomplexes suitable for optical microscopy and imaging of HER2-positive cells and tumors, as well as on the comprehensive evaluation of their pharmacokinetics, pharmacodynamics, and toxicological properties using cells and laboratory animals. The nanocomplexes represent a UCNP core/shell structure of the NaYF4:Yb,Er,Tm/NaYF4 composition coated with an amphiphilic alternating copolymer of maleic anhydride with 1-octadecene (PMAO) and conjugated to the Designed Ankyrin Repeat Protein (DARPin9-29) with high affinity to the HER2 receptor. We demonstrated the specific binding of UCNP-PMAO-DARPin to HER2-positive cancer cells in cultures and xenograft animal models allowing the tumor visualization for at least 24 h. An exhaustive study of the general and specific toxicity of UCNP-PMAO-DARPin including the evaluation of their allergenic, immunotoxic, and reprotoxic properties was carried out. The obtained experimental body of evidence leads to a conclusion that UCNP-PMAO and UCNP-PMAO-DARPin are functional, non-cytotoxic, biocompatible, and safe for imaging applications in cells, small animals, and prospective clinical applications of image-guided surgery.
关键词： nanotoxicology,pharmacodynamics,pharmacokinetics,animal imaging,upconversion nanoparticles,photoluminescent nanomaterials
更新于2025-11-21 11:08:12
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Molecularly imprinted based surface plasmon resonance nanosensors for microalbumin detection
摘要： Human serum albumin (HSA) is a major blood plasma protein also found in urine where its existence may be a marker of some types of liver or kidney dysfunction. Herein, we fabricated a novel surface plasmon resonance (SPR) nanosensor for selective, sensitive, and label-free microalbumin detection both in aqueous and urine sample solutions. Firstly, HSA-imprinted nanoparticles were synthesized, which consist of ethylene glycol dimethacrylate and N-methacryloyl-L-leucine as a cross-linker and functional monomer. The nanoparticles were characterized by zeta-size and scanning electron microscope analyses and were dropped onto the SPR chip surface to make HSA sensitive nanosensor. Characterization studies of HSA-imprinted SPR chip were carried out by atomic force microscopy, Fourier-transform infrared spectroscopy, contact angle, and ellipsometer. The limit of detection and limit of quantification values of HSA-imprinted SPR nanosensor were calculated as 0.7 pM and 1.9 pM for the concentration range of 0.15-500 nM. Selectivity studies of HSA-imprinted SPR nanosensor were achieved with hemoglobin and transferrin proteins which were chosen as competitor molecules. HSA-imprinted SPR nanosensor was displayed highly selective and sensitive to HSA.
关键词： surface plasmon resonance,nanosensor,nanoparticles,microalbumin detection
更新于2025-11-21 11:03:13
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A novel Ag nanoparticles/TiO2 nanowires-based photodetector and glucose concentration detection
摘要： A unique vapour transport cum glancing angle deposition (VT-GLAD) technique was employed to fabricate titanium dioxide (TiO2) nanowires (NWs). The NWs were grown and assembled to form the clusters. Both brookite (412) and rutile (002) phase for TiO2 was obtained from X-ray diffraction (XRD). The d spacing of ~ 1.37 ? was calculated from the transmission electron microscopy (TEM) of TiO2 NWs, which corresponds to (002) crystal plane. The silver (Ag) nanoparticles (NPs) on TiO2 NWs were grown using thermal evaporation cum GLAD technique. The presence of Ag NPs on the TiO2 NWs enhanced the photoconduction as compared to bare TiO2 NWs device. The maximum photosensitivity of the Ag NPs/TiO2 NWs based device was recorded ~ 1.6 times compared to the bare TiO2 NWs based device at ? 2.5 V. The Ag NPs containing device was highly UV sensitive and maximum responsivity for the device was calculated to be ~ 2.3 A/W at 370 nm. The device also possessed high responsivity rejection (RR) ratio of ~ 6.5 between UV (370 nm) and visible (450 nm) light. The Ag NPs decorated TiO2 NWs based detector also showed response to white light. The different concentration of glucose into deionised (DI) water-based solution was detected precisely under white light illumination. The normalised (light/dark) detector current/glucose concentration value was decreased from ~ 0.19 to ~ 0.05 at ? 2.5 V, with an increase in glucose concentration into the solution from 40 mg/dl to 200 mg/dl.
关键词： photodetector,Ag nanoparticles,TiO2 nanowires,VT-GLAD technique,glucose concentration detection
更新于2025-11-21 11:01:37
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One-Pot Synthesis of Gel Glass Embedded with Luminescent Silicon Nanoparticles
摘要： Preparation of highly luminescent glasses involves expensive and complicated processes and usually requires high temperature. In this work, we show that luminescent silicon (Si) nanoparticle (NP)- embedded silicate gel glasses can be developed under near-ambient conditions by a remarkably simple, one-pot strategy, without using any sophisticated instrumentation or technique. Simultaneous hydrolysis and reduction of (3-aminopropyl)triethoxysilane leads to the formation of colloidal Si nanocrystals that can be transformed to a glassy phase upon slow evaporation followed by freezing. Structural investigations reveal the formation of a sodium silicate gel glass framework having discernible shear bands, along with embedded Si NPs. High photoluminescence quantum yield (ca. 35?40%), low glass-transition temperature (Tg ≈ 66?73 °C), strain-tolerant mechanical stability, and inexpensive preparation make the glass attractive for applications as display materials and photonic converters.
关键词： luminescence,silicon,gel glass,nanoparticles,photon conversion
更新于2025-11-21 11:01:37