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Smart Golden Leaves Fabricated by Integrating Au Nanoparticles and Cellulose Nanofibers
摘要： A simple processing technology based on spontaneous arrangement of gold nanoparticles (AuNPs) on cellulose nanofibers (CNFs) makes it possible to form a gold leaf with superior mechanical, chemical and electrical characteristics with a small amount of gold (< 15 vol.%). The electrical resistivity of the AuNP/CNF hybrid film reached 8.7 × 10?? Ω cm at 13 vol.% corresponding to that of a gold plate (2.9 × 10?? Ω cm) through a distribution of AuNP inside the film in the form of a band. The AuNPs work not only as linkers between various CNFs in the hybrid structure but also as scaffolds. Self-assembly allows the formation of leaves on three-dimensional micrometer-sized substrates, on which it is impossible to form a uniform flexible metallic layer using conventional techniques such as sputtering, vapor deposition, and electroless plating. The hybrid film holds great promise as a novel gold leaf for a wide range of applications, including coatings, smart papers, electronic skins, and wearable devices owing to its unique combination of superior properties, as well as good productivity, processability, and renewability.
关键词： cellulose nanofiber,organic/inorganic hybrid film,self-healing,spontaneous binding,gold nanoparticle
更新于2025-09-19 17:15:36
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Expedient paramagnetic properties of surfactant-free plasmonic silicon-based nanoparticles
摘要： Surfactant-free multifunctional semiconductor-metallic nanostructures possessing several modalities are formed due to laser-induced structural modification of pure silicon nanoparticles in the presence of gold. It results to variable size-dependent chemical composition examined by energy-dispersive X-ray spectroscopy. Laser-synthesized silicon-based nanocomposites exhibit remarkable both plasmonic and paramagnetic properties. Their plasmonic maxima are found to be easily adjusted in the whole visible spectral range. Influence of resonant laser irradiation on spin behaviour of silicon-gold nanoparticles is established. Their spin–lattice and spin–spin relaxation processes are investigated as well. Such multifunctional nanoparticles can reveal a huge potential for different applications in field of nanomedicine, in particular, for biosensing and bioimaging.
关键词： Nanocomposite,Silicon-gold nanoparticle,Plasmonic property,Silicon nanoparticle,EPR,Laser ablation
更新于2025-09-19 17:13:59
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Photothermal performance of plasmonic patch with gold nanoparticles embedded on polymer matrix
摘要： Under light irradiation, gold nanoparticles (AuNPs) reveal the surface plasmon feature, i.e., the occurrence of the collective excitation of the free electrons of NPs. Plasmon relaxation, as well as excitation, induced by light absorption, could be used to increase the local temperature via conversion of light to heat. This photothermal effect can be enhanced by control of the morphology and structure of NPs in the near-infrared (NIR) region. Recently, the use of an NP-composited polymer as a heating patch with a good photothermal performance was suggested for biomedical applications. Herein, AuNPs embedded on polydimethylsiloxane (PDMS) films (Au-PDMS) were successfully prepared with an in-situ synthesis method without a reducing agent. Their photothermal performance was measured with an IR camera under 808 nm NIR irradiation, and a mechanical stretching test for the Au-PDMS films was conducted to investigate the effect of the AuNPs’ density on the photothermal performance. The surface temperature of the films, which reached 120 oC within 1 min, is also adjustable with mechanical stretching (strain change). This is due to the decrease of the AuNPs density with widening interparticle distance between them.
关键词： PDMS,Gold Nanoparticle,Near-infrared,Plasmonic Patch,Photothermal,Surface Plasmon
更新于2025-09-19 17:13:59
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A DNA origami plasmonic sensor with environment-independent read-out
摘要： DNA origami is a promising technology for its reproducibility, flexibility, scalability and biocompatibility. Among the several potential applications, DNA origami has been proposed as a tool for drug delivery and as a contrast agent, since a conformational change upon specific target interaction may be used to release a drug or produce a physical signal, respectively. However, its conformation should be robust with respect to the properties of the medium in which either the recognition or the read-out take place, such as pressure, viscosity and any other unspecific interaction other than the desired target recognition. Here we report on the read-out robustness of a tetragonal DNA-origami/gold-nanoparticle hybrid structure able to change its configuration, which is transduced in a change of its plasmonic properties, upon interaction with a specific DNA target. We investigated its response when analyzed in three different media: aqueous solution, solid support and viscous gel. We show that, once a conformational variation is produced, it remains unaffected by the subsequent physical interactions with the environment.
关键词： molecular detection,DNA origami,gold nanoparticle,plasmonic sensor
更新于2025-09-19 17:13:59
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A Review on Additives for Halide Perovskite Solar Cells
摘要： In this assay, a new polyethyleneimine-gold nanoparticles-protoporphyrin cobalt (II) (PEI-AuNPs-CoPP) nanocomposite was synthesized by a simple method under mild conditions, and it was used to fabricate an electrochemical sensor for the detection of hydrogen peroxide (H2O2). The structures of nanomaterials were characterized by fourier transform infrared (FTIR) spectroscopy and ultraviolet visible spectrometry (UV–vis). Under the optimum condition, the current intensity was linearly related to H2O2 concentration in the range of 50–280 aM (R2 = 0.9932). It's worth mentioning that a lower detection limit of 7.26 aM was obtained at a signal-to-noise rate of 3. In addition, the experiments showed that ascorbic acid (AA), uric acid (UA) and glucose (Glu) had little effect on the determination of H2O2. The sensor had a good analytical performance for the determination of H2O2 in human serum samples. These results suggested that the proposed PEI-AuNPs-CoPP nanocomposites had practical application prospect in biological sample analysis and clinical diagnosis.
关键词： Hydrogen peroxide sensor,Polyethyleneimine,Gold nanoparticle,Protoporphyrin cobalt (II)
更新于2025-09-19 17:13:59
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Controlled Fabrication of Optical Signal Input/Output Sites on Plasmonic Nanowires
摘要： Silver nanowires have attracted considerable attention as sub-diffraction limited diameter waveguides in a variety of applications including cell endoscopy and photonic integrated circuitry. Optical signal transport occurs by coupling light into propagating surface plasmons which scatter back into light further along the wire. However these inter-conversions only occur efficiently at wire ends, or at defects along the wire, which are not controlled during synthesis. Here we overcome this limitation, demonstrating the visible laser light-induced fabrication of gold nanostructures at desired positions on silver nanowires, and their utility as efficient in/out coupling points for light. The gold nanostructures grow via plasmon-induced reduction of Au(III) and are shown to be excellent ‘hotspots’ for surface-enhanced Raman scattering.
关键词： optical antenna,surface enhanced Raman scattering,Chemically synthesized noble metal nanowires,gold nanoparticle,laser direct writing
更新于2025-09-19 17:13:59
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Highly sensitive and selective localized surface plasmon resonance biosensor for detecting glutamate realized on optical fiber substrate using gold nanoparticles
摘要： In this study, we fabricated and characterized a localized surface plasmon resonance-based biosensor comprising gold nanoparticles (AuNPs) on an optical fiber substrate to detect glutamate at concentrations ranging from 0 to 10 mM. To fabricate the probe, AuNPs were decorated on an unclad portion of an optical fiber, and the enzyme glutamate dehydrogenase and coenzyme nicotinamide adenine dinucleotide were co-immobilized over the AuNPs. The sensor was designed to operate according to an intensity modulation scheme where the absorbance changed as the glutamate concentration varied in the sample around the probe. The change in the absorbance was due to the chemical reaction between glutamate dehydrogenase, glutamate, water and NAD+ which affected the refractive index of the medium around the AuNPs. The changes in the local refractive index led to significant variations in the absorbance of the AuNPs present in the sensing layer. The change recorded in the absorbance by AuNPs was 0.019 for the glutamate concentration range from 0 to 10 mM. The limit of detection and sensitivity of the sensor were determined as 0.36 mM and 0.0048 AU/mM, respectively. The sensor has advantages in terms of its low cost, immunity to electromagnetic interference, miniaturized probe, and capability of online monitoring and remote sensing because an optical fiber is used as the substrate for probe fabrication.
关键词： Localized surface plasmon resonance,Glutamate,Optical fiber,Gold nanoparticle,Sensor
更新于2025-09-16 10:30:52
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Temperature Variations of Gold Nanoparticle and Dynamics of Plasmonic Bubble in Water Under Nanosecond Pulsed Laser
摘要： Suspended gold nanoparticle in water medium starts to warm up under nanosecond laser irradiation and creates a bubble around itself. The present study aims at evaluating the amount of nanoparticle size reduction at boiling temperature, the temperature variations of the nanoparticle, and its medium and finally the bubble formation moment. To this aim, Mie theory was used to calculate the absorption cross section of the nanoparticle in proximity of the bubble. Heat transfer equations were applied to determine the temperature of the nanoparticle and water. In addition, hydrodynamic equations were initiated to evaluate the expansion of the bubble. Then, these three groups of equations were coupled together and solved numerically. Based on the results, the bubble forms at the critical pressure and consequently due to the slow bubble velocity, temperature gradient in the medium is observed. Further, slight pulse width variations play a significant role on the nanoparticle temperature. The calculation of the nanoparticle heating associated with the creation of the bubble helps in controlling nanoparticle size and understanding the nanoscale heat transfer processes.
关键词： Gold nanoparticle,Nano bubble,Nanoparticle heating,Hydrodynamic equations
更新于2025-09-12 10:27:22
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Plasmonic ELISA based on DNA-directed gold nanoparticle growth for Cronobacter detection in powdered infant formula samples
摘要： The traditional gold nanoparticle (AuNP) growth-based plasmonic ELISA (pELISA) strictly and directly controlled by reducing reagents can achieve high sensitivity, but it remains fragile toward the surrounding environment. This work developed a sandwich pELISA for Cronobacter detection in powdered infant formula samples by mediating AuNP growth through DNA. In this assay, DNA adsorbed on the surface of gold nanoseeds guided the anisotropic crystal growth with hydroxylamine as a reducing reagent, and the catalase–hydrogen peroxide (Cat–H2O2) system was introduced to bridge the DNA-directed AuNP growth and pELISA, as such DNA can be cleaved into fragments by the hydroxyl radical generated from oxidation of H2O2 through Fenton reagents. Under optimized conditions, the proposed pELISA can qualitatively detect Cronobacter species (Cronobacter muytjensii ATCC 51329) by the naked eye with a cut-off limit of 3 × 105 cfu/mL. This method also revealed a good linear range (3 × 102 to 3 × 107 cfu/mL) for quantitative detection of C. muytjensii ATCC 51329 with a limit of detection of 1.6 × 102 cfu/mL, which is approximately 162.5 times lower than that of horseradish peroxidase-based conventional ELISA (2.6 × 104 cfu/mL). By taking advantage of highly stable DNA-directed AuNP growth, the proposed method shows a good performance in powdered infant formula samples spiked with different concentrations of C. muytjensii ATCC 51329 with average recoveries ranging from 90.79 to 119.09% and coefficient of variation ranging from 4.24 to 9.55%. These values corresponded to an acceptable accuracy and precision for the proposed method. In brief, this work shows potential for screening other analytes in food safety, clinical diagnostics, and environmental monitoring.
关键词： gold nanoparticle growth,Cronobacter,powdered infant formula,plasmonic enzyme-linked immunosorbent assay,DNA-directed
更新于2025-09-12 10:27:22
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Femtosecond Laser Ablation Synthesis of Nanoparticles and Nano-Hybrides in Ethanol Medium
摘要： The nanoparticle production has a significant importance because of its unique optical properties in molecular biology and medicine. Plasmonic metallic nanoparticles are widely used in cancer monitoring studies as contrast agents on the account of their surface plasmon resonance (SPR) effect. Beside, silicon (Si) semiconductor nanoparticles can provide several beneficial properties that they are used commonly intensifying the detecting signals. Nanoalloys/Nanohybides/Nanocomposites are more functional materials than a single material structure and having many restrictions. At that point, the application of Pulsed Laser Ablation (PLA) technique has many advantages if applied in the liquid. Since no any chemical technique is applied, this procedure promises a clean synthesis process; it is a simple and economical technique in the production process. It provides some possibilities to generate particles in the desired size, shape and density, and these properties of nanoparticles produced can be controlled by controlling the laser parameters. In this work, we have focused on the production of nanoparticles to rid off chemical processes using femtosecond laser ablation technique, and this technique presents a process to reach the fast and reliable results for production of nanoshells, nanocomposites and all nanoforms of particles. We have produced Si@Au nanohybrids in ethanol medium using femtosecond laser ablation depending on laser pulse energy. Absorption spectra were recorded day by day to determine the optical characteristics of produced nanoparticles within these time durations, Transmission Electron Microscopy (TEM) images were obtained for monitoring and determining the size/structure of nanoparticles, energy dispersive spectroscopy (EDS) for material compositions were produced, these results obtained are presented in the scope of this paper.
关键词： silicon,ablation,femtosecond laser,gold,Nanoparticle
更新于2025-09-12 10:27:22