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PET Imaging of the EPR Effect in Tumor Xenografts Using Small 15 nm Diameter Polyethylene Glycols Labeled with Zirconium-89
摘要： The goal was to develop and characterize a companion diagnostic for the releasable PEG40kDa~SN-38 oncology drug, PLX038, that would identify tumors susceptible to high accumulation of PLX038. PEG conjugates of the zirconium ligand desferroxamine B (DFB) of similar size and charge to PLX038 were prepared that contained one or four DFB as well as one that contained three SN-38 moieties and one DFB. Uptake and associated kinetic parameters of the 89Zr-labeled nanocarriers was determined in tumor and normal tissues in mice using μPET/CT imaging. The data were fit to physiologically-based pharmacokinetic models to simulate the mass-time profiles of distribution of conjugates in the tissues of interest. The time activity curves for normal tissues showed high levels at the earliest time of measurement due to vascularization, followed by a monophasic loss. In tumors, levels were initially lower than in normal tissues but increased to 9 to 14% of injected dose over several days. The efflux half-life in tumors was a very long ~400 h. and tumor levels remained at about 10% ID nine days after injection. Compared to diagnostic liposomes, the PEG nanocarriers have a longer serum half-life, are retained in tumors at higher levels, remain there longer, and afford higher tumor exposure. The small PEG40kDa nanocarriers studied here show properties for passive targeting of tumors that are superior than most nanoparticles and might be effective probes to identify tumors susceptible to a similar size therapeutic nanocarriers such as PLX038.
关键词： nanoparticle,imaging,Enhanced permeability and retention,tumor,pharmacokinetics,theranostics
更新于2025-09-23 15:19:57
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Tailoring optoelectronic properties of CH3NH3PbI3 perovskite photovoltaics using al nanoparticle modified PC61BM layer
摘要： In photovoltaics, light harvesting is one of the critical factors for the enhancement of power conversion efficiency (PCE). Photon harvesting can be carried out by various methods in perovskite photovoltaic. The improved light harvesting can also be achieved by trapping the light by incorporating metallic nanoparticles at the interface or in the perovskite active layer itself. Either light is absorbed or scattered by metallic nanoparticles depending on the particle size. When light is absorbed by the nanoparticles (size < 20 nm), it behaves like a sub-wavelength antenna due to localized surface plasmon resonance (LSPR) excitation and hence near field effect of plasmonic particle will be interacting to CH3NH3PbI3 active layer. Larger particles (> 20 nm) act as sub-wavelength scattering centers of light and help in trapping incident light. In order to make use of dual effect poly-dispersed spherical aluminium nanoparticles (AlNPs) (size – 20–70 nm) were incorporated in the CH3NH3PbI3 perovskite solar cell at the PC61BM/Al electrode interface. As a result, there is an increase in the optical absorption in the AlNPs embedded device. A detailed study of optical absorption, absorbed light emission characteristics charge trap density and carrier concentration studies, photovoltaic property measurements indicates, improvement in power conversion efficiency arise due to enhancement in JSC. Evaluated device properties indicate that enhancement in JSC arises due to improvement in the active layer photon absorption by both scattering and plasmonic effect in addition to reduced series resistance.
关键词： Trap states,Organic-inorganic halide perovskite solar cell,Ultraviolet plasmonic resonance,Plasmonic nanoparticle current density,Metal nanoparticles
更新于2025-09-23 15:19:57
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Structurally and Compositionally Tunable Absorption Properties of AgCl@AgAu Nanocatalysts for Plasmonic Photocatalytic Degradation of Environmental Pollutants
摘要： Composite nanomaterials having Ag nanoparticles (NPs) that decorate nanostructured AgCl (Ag/AgCl) are promising as plasmonic photocatalysts because of the visible-light absorption of Ag NPs. However, the narrow absorption bands of Ag NPs near 400 nm cause inefficient absorption in the visible range and, consequently, unsatisfactory photocatalytic activity of Ag/AgCl nanomaterials. In this study, we introduce a new class of AgCl-based photocatalysts that are decorated with bimetallic Ag and Au NPs (AgCl@AgAu NPs) for visible-light-driven photocatalytic degradation of organic pollutants. Polyvinylpyrrolidone induces selective reduction of noble metal precursors on AgCl while leaving AgCl intact. The extended composition of the decorating NPs red-shifts the absorption band to 550–650 nm, which allows the catalysts to take advantage of more energy in the visible range for improved efficiency. Furthermore, we control the structures of the AgCl@AgAu NPs, and investigate their correlation with photocatalytic properties. The versatility, chemical stability, and practical application of the AgCl@AgAu NPs are demonstrated using various organic pollutants, recycling experiments, and natural aqueous media, respectively. Our fundamental investigation on the synthesis and applications of AgCl-based nano-photocatalysts is highly valuable for designing plasmonic photocatalysts and expanding their utilization.
关键词： organic pollutant,photocatalyst,nanoparticle,silver,AgCl,surface plasmon resonance,PVP,visible light,gold
更新于2025-09-23 15:19:57
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Preparation of Silver Nanoparticles Dispersed in Almond Oil Using Laser Ablation Technique
摘要： Nanoparticle production by pulsed laser ablation (PLA) is a process that can generate pure nanoparticles (NPs) straight from a varied range of bulk substances and compounds. Silver nanoparticles (Ag NPs) are probably one of the most attractive noble metal nanostructures because of their unique and interesting physical and chemical properties. In this study, laser ablation of pure silver plate immersed in almond oil was carried out for Ag NPs production. Nd: Yag laser of wavelength 1064 nm, was used for the ablation of the Ag plate at different laser energies and ablation times. The almond oil permitted the formation of Ag NPs with a stable and homogeneity particle diameter in a reasonable time. The size distribution of the NPs was examined by High-Resolution Transmission Electron Microscopy (HRTEM). The particle sizes of the produced Ag NPs at laser energy 200 mJ in the solution at 10,15 and 20-min ablation times were 4.82, 3.11 and 1.82 nm respectively. The particle sizes of Ag NPs produced at different laser energies 150,200 and 250 mJ and at ablation time 10 min inside the solution were 5.39,4.82 and 1.92 nm respectively. The absorption peaks of the produced nanoparticles have been characterized using a UV-Vis spectrophotometer.
关键词： Laser ablation,almond oil,metal nanoparticle
更新于2025-09-23 15:19:57
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Signal amplification and quantification on lateral flow assays by laser excitation of plasmonic nanomaterials
摘要： Lateral flow assay (LFA) has become one of the most widely used point-of-care diagnostic methods due to its simplicity and low cost. While easy to use, LFA suffers from its low sensitivity and poor quantification, which largely limits its applications for early disease diagnosis and requires further testing to eliminate false-negative results. Over the past decade, signal enhancement strategies that took advantage of the laser excitation of plasmonic nanomaterials have pushed down the detection limit and enabled quantification of analytes. Significantly, these methods amplify the signal based on the current LFA design without modification. This review highlights these strategies of signal enhancement for LFA including surface enhanced Raman scattering (SERS), photothermal and photoacoustic methods. Perspectives on the rational design of the reader systems are provided. Future translation of the research toward clinical applications is also discussed.
关键词： gold nanoparticles,lateral flow assay,nanoparticle heating,signal amplification and quantification,SERS
更新于2025-09-23 15:19:57
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Synthesis of diameter controlled multiwall carbon nanotubes by microwave plasma-CVD on low-temperature and chemically processed Fe nanoparticle catalysts
摘要： Properties of carbon nanotubes sensitively depend on the structural configuration, e.g., chirality, diameter, layer number and the compositional characteristics. The size of catalyst nanoparticles used to grow the CNTs significantly controls its diameter. Generally, catalyst nanoparticles are size-optimized via high-temperature annealing of thin metal films. Presently, formation of size-controlled Fe nano-particles as the efficient catalyst has been pursued via a low-temperature (TCG) wet chemical process that bypasses the high-temperature annealing step and leads to a low average size of catalyst nanoparticles. Suitable progress of the oxidation–hydrolysis reactions of metal-bearing ferrite entities controls the crystallinity via dehydration of the intermediate constituent and diminution of the oxide component. Optimally low diameter Fe nanoparticles have been obtained at temperature around TCG ~ +10 °C via simultaneous prominent aerial oxidation and neutralization in a single step. In this present work multiwall carbon nanotubes of controlled diameter (~15–25 nm) have been produced by relatively low-temperature (~300 °C) plasma processing, using pre-designed shadow-mask assembly to create diffused and remote-plasma of (CH4 + H2) and CO2 as a weak oxidizing gas to selectively remove the surplus amorphous components, and also by controlling the size of catalyst Fe-nanoparticles on the substrate via low-temperature non-plasma synthesis process.
关键词： Carbon nanotube,Fe-nanoparticle synthesis,Diameter controlled growth,2.54 GHz microwave plasma,Raman scattering
更新于2025-09-23 15:19:57
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Reconfigurable Plasmonic Nanostructures Controlled by DNA Origami
摘要： Precise surface functionalization and reconfigurable capability of nanomaterials are essential to construct complex nanostructures with specific functions. Here we show the assembly of a reconfigurable plasmonic nanostructure, which executes both conformational and plasmonic changes in response to DNA strands. In this work, different sized gold nanoparticles(AuNPs) were arranged site-specifically on the surface of a DNA origami clamp nanostructure. The opening and closing of the DNA origami clamp could be precisely controlled by a series of strand displacement reactions. Therefore, the patterns of these AuNPs could be switched between two different configurations. The observed plasmon band shift indicates the change of the plasmonic interactions among the assembled AuNPs. Our study achieves the construction of reconfigurable nanomaterials with tunable plasmon ic interactions, and will enrich the toolbox of DNA-based functional nanomachinery.
关键词： DNA origami,Reconfigurable nanostructure,Gold nanoparticle,Plasmonic nanostructure
更新于2025-09-23 15:19:57
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Fluorometric virus detection platform using quantum dots-gold nanocomposites optimizing the linker length variation
摘要： In this study, a tunable biosensor using the localized surface plasmon resonance (LSPR), controlling the distance between fluorescent CdZnSeS/ZnSeS quantum dots (QDs) and gold nanoparticles (AuNPs) has been developed for the detection of virus. The distance between the AuNPs and QDs has been controlled by a linkage with a peptide chain of 18 amino acids. In the optimized condition, the fluorescent properties of the QDs have been enhanced due to the surface plasmon effect of the adjacent AuNPs. Successive virus binding on the peptide chain induces steric hindrance on the LSPR behavior and the fluorescence of QDs has been quenched. After analyzing all the possible aspect of the CdZnSeS/ZnSeS QD-peptide-AuNP nanocomposites, we have detected different concentration of influenza virus in a linear range of 10?14 to 10?9 g?mL?1 with detection limit of 17.02?fg?mL?1. On the basis of the obtained results, this proposed biosensor can be a good alternative for the detection of infectious viruses in the various range of sensing application.
关键词： Quantum dots,Localized surface plasmon resonance,Biosensor,Peptide,Influenza virus,Gold nanoparticle
更新于2025-09-23 15:19:57
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Design, Molecular Modeling and Synthesis of Metal-Free Sensitizers of Thieno Pyridine Dyes as Light-Harvesting Materials with Efficiency Improvement Using Plasmonic Nanoparticles
摘要： Considering the thiophene unit as an electron-rich heterocycle, it is investigated with the aim of elucidating its potential efficiency for solar cell application. With the introduction of active substituents such as COOEt, CONH2 and CN into the thiophene segment, three novel thieno pyridine sensitizers (6a–c), based on donor-acceptor D-π-A construction, are designed and synthesized. The effect of the anchoring groups is investigated based on their molecular orbital’s (MO’s) energy gap (Eg). The electrostatic interaction between the synthesized dyes and metal nanoparticles, namely gold, silver and ruthenium, is believed to improve their performance as organic sensitizers. The dye-sensitized solar cells (DSSCs) are manufactured using the novel diazenyl pyridothiophene dyes, along with their metal nanoparticles conjugates as sensitizers, and were examined for efficiency improvement. Accordingly, using this modification, the photovoltaic performance was significantly improved. The promising results of conjugate (6b/AgNPs), compared with reported organic and natural sensitizers (JSC (1.136 × 10?1 mA/cm2), VOC (0.436 V), FF (0.57) and η (2.82 × 10?2%)), are attributed to the good interaction between the amide, methyl, amino and cyano groups attached to the thiophene pyridyl scaffolds and the surface of TiO2 porous film. Implementation of a molecular modeling study is performed to predict the ability of the thiophene moiety to be used in solar cell applications.
关键词： metal nanoparticle,plasmonic,organic sensitizers,tetrahydrobenzothiophenes,dye-sensitized solar cells,thienopyridine,HOMO-LUMO
更新于2025-09-23 15:19:57
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Assembly of Conductive Polyaniline Microstructures by a Laser-Induced Microbubble
摘要： Micro-patterns of conductive polymers are key for various applications in the fields of flexible electronics and sensing. A bottom-up method that allows high-resolution printing without additives is still lacking. Here, such a method is presented based on micro-printing by the laser-induced microbubble technique (LIMBT). Continuous micro-patterning of polyaniline (PANI) was achieved from a dispersion of the Emeraldine base form of PANI (EB-PANI) in n-methyl-2-pyrrolidone (NMP). A focused laser beam is absorbed by the EB-PANI nanoparticles and leads to formation of a microbubble, followed by convection currents, which rapidly pin EB-PANI nanoparticles to the bubble/substrate interface. Micro-Raman spectra confirmed that the printed patterns preserve the molecular structure of EB-PANI. A simple transformation of the printed lines to the conducting Emeraldine salt form of PANI (ES-PANI) was achieved by doping with various acid solutions. The hypothesized deposition mechanism was verified, and the resulting structures were characterized by microscopic methods. The micro-structures displayed conductivity of 3.8×10-1 S/cm upon HCl doping and 1.5×10-1 S/cm upon H2SO4 doping, on par with state-of-the-art patterning methods. High fidelity control over the width of the printed lines down to ~650 nm was accomplished by varying the laser power and microscope stage velocity. This straightforward bottom-up method using low power lasers offers an alternative to current microfabrication techniques.
关键词： laser printing,nanoparticle assembly,polyaniline,microbubble,directed assembly
更新于2025-09-23 15:19:57