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oe1(光电查) - 科学论文

104 条数据
?? 中文(中国)
  • Label-free detection of liver cancer based on silver nanoparticles coated tissue surface-enhanced Raman spectroscopy

    摘要: Surface-enhanced Raman spectroscopy (SERS) was employed to obtain hepatocellular carcinoma (HCC) tissue spectra with coated silver nanoparticles. Principal component analysis (PCA) combined with linear discriminate analysis (LDA) was introduced to analyze the obtained spectra. The sensitivity and specificity of discrimination for HCC and normal group is 93.8% and 100%. While that is 79.2% and 93.8% for HCC and adjacent HCC group, this study suggests a great potential method for early HCC detection by combination of silver nanoparticles based tissue SERS and PCA-LDA analysis.

    关键词: silver nanoparticles,surface-enhanced Raman spectroscopy (SERS),linear discriminate analysis,hepatocellular carcinoma,principal component analysis

    更新于2025-09-09 09:28:46

  • Synthesis and Electrochemical Characterization of AgNP Ink Suitable for Inkjet Printing

    摘要: To meet the growing demand for inkjet printable nanoparticle-based conductive inks, novel synthetic approaches are needed. In this study, spherical silver nanoparticles (AgNPs) with a mean diameter of approximately 2.5 nm were synthesized by the reduction of silver nitrate using an aqueous hydrazine solution in the presence of poly(acrylic acid) as a capping agent. The main goal of this work was the implementation of cyclic voltammetry as an electrochemical method for studying both the absorption of poly(acrylic acid) on the grain surface and nanoparticle interactions. The same technique was used to determine equimolar additions of hydrazine to obtain a high yield of reduced silver. All solutions used in the experiments were prepared at a high molar concentration. Silver nanoparticle-based ink was prepared by dispersing dried nanoparticles into a mixture of water and ethylene glycol and was stable for over seven months. For a comprehensive study of the prepared nanoink, UV-visible and electronic microscopy measurements were carried out. An inkjet technology was applied to deposit conductive ink to form linear silver tracks on a flexible substrate. These tracks exhibited a resistivity of 8.0×10-8 ?m.

    关键词: conductive ink,poly(acrylic acid),cyclic voltammetry,Inkjet printing,silver nanoparticles

    更新于2025-09-09 09:28:46

  • EFFECT OF TEMPERATURE ON NANOCOMPOSITE OF METAL NANOPARTICLES IN PHOTONIC CRYSTALS

    摘要: We theoretically investigate the photonic band gaps in one-dimensional photonic crystals based on nanocomposite of silver nanoparticles. The dielectric permittivity is calculated in accordance with temperature dependence of plasma frequency of silver nanoparticle. The effect of temperature on these structures by incorporating the volume expansion coefficient of nanoparticle is analysed. The behaviors of photonic band gaps with variation of filling factor, radii of nanoparticle and temperature are observed. The evolution of these results leads to designing the desired photonic crystals.

    关键词: photonic crystals,nanocomposite,photonic band gaps,temperature dependence,silver nanoparticles

    更新于2025-09-09 09:28:46

  • Study of interaction between citrate-coated silver nanoparticles and gamma globulin using spectroscopic method

    摘要: Studies on the biomedical applications of silver nanoparticles (AgNPs) have attracted great attention during the past decades. In this paper, the citrate-coated AgNPs with uniform size and good monodispersity are synthesized. The diameter of the synthesized AgNPs is about 25.4 nm. Its interaction with γ-globulin was thoroughly studied using UV-vis absorption spectroscopy, fluorescence spectroscopy, fluorescence lifetime measurement, synchronous fluorescence spectroscopy, 3D fluorescence spectroscopy as well as CD spectroscopy. From the above experiments, we can obtain that citrate-coated AgNPs can bind to γ-globulin with high affinity. The fluorescence quenching of γ-globulin by AgNPs is in a static mechanism. Van der Waals interactions and hydrogen bonds play great role in the binding interaction. The interaction can induce slight conformational change of γ-globulin.

    关键词: citrate-coated,γ-globulin,interaction,silver nanoparticles,spectroscopic method

    更新于2025-09-09 09:28:46

  • [IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Facile Preparation of Silver Nanoparticles Decorated Boron Nitride Nanotube Hybrids

    摘要: Blending polymer with thermally conductivity Metal nanoparticles-fillers, which can reducing ITR at a high fillers contents, have recently attracted intense attention. The interfacial thermal resistance (ITR) between fillers at a high filler doping contents causes a limited improvement of thermal conductivity. Fortunately, silver nanoparticles decorated fillers have potential to improve thermally conductivity by reducing ITR between fillers at a high filler content. However, how to fabricate pony-size silver nanoparticles decorated fillers hybrids simply is still a challenge. Herein, we report a facile synthesis of decorating boron nitride nanotube (BNNT) hybrids with AgNP (10-20 nm) by replacing between the Ag+ and -OH on the defect sites of BNNT. This strategy is a viable way to prepare metal nanoparticles-fillers which can be used in highly thermal conductivity.

    关键词: boron nitride nanotube,thermal conductivity,hybrids,silver nanoparticles,interfacial thermal resistance

    更新于2025-09-09 09:28:46

  • A Biomedical Surface Enhanced Raman Scattering Substrate: Functionalized Three-Dimensional Porous Membrane Decorated with Silver Nanoparticles

    摘要: We fabricated a simple, cheap, and functional surface enhanced Raman scattering substrate for biomedical application. Hotspots between two close silver nanoparticles distributed in the skeleton of a three-dimensional porous membrane, especially in the pores, were formed. The dual poles of micropores in the membrane were discussed. The pores could protect the silver nanoparticles in the pores from being oxidized, which makes the membrane effective for a longer period of time. In addition, Staphylococcus aureus cells could be trapped by the micropores and then the Raman signal became stronger, indicating that the functional surface enhanced Raman scattering substrate is reliable.

    关键词: three-dimensional porous membrane,biomedical application,silver nanoparticles,surface enhanced Raman scattering

    更新于2025-09-09 09:28:46

  • Paper-based Versatile SERS Chip with Smartphone-based Raman Analyzer for Point of Care Application

    摘要: With the advanced development of the miniaturized Raman spectroscopy, surface enhanced Raman spectroscopy (SERS) has extended its applications into the field of Point of Care Testing (POCT) and demonstrated its great significance in virtue non-invasive property and capability of fingerprint identification. In the SERS-based analysis and/or sensing system, the preparation of low cost, high-performance SERS substrate is critically important. In this manuscript, vacuum filtration is utilized to fabricate the silver nanoparticles (AgNPs) embedded nylon filter membrane (ANFM) as flexible paper-based SERS chips. By characterizing the typical analytes with the miniaturized smartphone-based Raman analyzer, the proposed SERS chips have successfully demonstrated good sensitivity, repeatability and stability. The lowest concentration as detected can approach 1 pmol for Rhodamine 6G (RH6G) and 10 pmol for both crystal violet (CV) and malachite green (MG), respectively. With the help of microporous structure of the membrane, the ANFM based SERS chips can implement the separation of small molecules from complex mixture and can achieve “purified” SERS signals of targeted molecules. Besides, with the function of anti-friction resistance and flexibility, the ANFM can serve as SERS papers to pre-concentrate the contaminates by multiple swapping and further enhance the SERS signals for point of care analysis. Therefore, we demonstrate multi-functions of the flexible ANFM based SERS chips, which provides a promising solution for the POCT analysis with SERS technique on account of its flexibility and low fabrication cost.

    关键词: silver nanoparticles,SERS chips,nylon filter membrane,Point of Care Testing,smartphone-based Raman analyzer,Surface-enhanced Raman spectroscopy

    更新于2025-09-09 09:28:46

  • [IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Polymer/Ag Nanoparticles Composite for Chloroform Detection

    摘要: In this paper we report on changes in the extinction spectra of a nanocomposite consisting of Ag nanoparticles arranged into poly(glycidyl methacrylate) host matrix. Two collective surface plasmon modes denoted as P and T were identified in the spectrum. They associated with electric dipoles perpendicular and parallel to the plane of the array respectively. It was found experimentally that intensity and bandwidth of corresponding bands decrease when the nanocomposite is exposed to chloroform vapor. At the same time, both plasmon bands shift toward shorter wavelength. Those dependences can be explained by weakening of the electrodynamic coupling between LSPR in neighboring nanoparticles due to the increase of the distance between particles caused by swelling of the polymer matrix. The spectral changes are fully reversible. It was found that sensitivity of the nanocomposite sensor to chloroform vapor is 0.02 nm/ppm with the response time t=25 s.

    关键词: composite,localized surface plasmon resonanse,silver nanoparticles,vapor sensor

    更新于2025-09-09 09:28:46

  • Physical Properties of Pure and Nano Ag Doped Liquid Crystalline Compounds Containing 1,3,4-Oxadizole Unit

    摘要: Dielectric properties and other physical properties such as electrical conductivity (AC) and relaxation time or activation energy have been studied for two systems pure LC [V]6,6, [V]7,6, [V]8,6, [V]6,7, [V]7,7 and [V]8,7 and their doped with silver nanoparticles. The results show the increasing in real dielectric permittivity ? with increasing length terminal chain. So the real dielectric permittivity increasing with raising temperature. To compare between the values of (400) Hz and (4000) Hz we observe these values at the low frequency are larger than that in high frequency. Generally, one can see that the doping of Ag nano particles effectively reduced the permittivity of the LC materials with its large electric dipole moment. The electrical conductivity σ value for pure LC samples in general increases with increasing temperature. So we observed increasing of electrical conductivity values at high frequency. The time scale is discussed in terms of the Arrhenius plot. Generally, with increasing the temperature the time period that spends by molecules at the transition state will increase. The activation energy Ea values show the increase in the activation energy to the doped systems.

    关键词: Dielectric permittivity,Doped liquid crystals,Liquid crystals,Relaxation time,Electrical conductivity,Activation energy,Silver nanoparticles

    更新于2025-09-04 15:30:14

  • Antioxidant and Photocatalytic Activity of Aqueous Leaf Extract Mediated Green Synthesis of Silver Nanoparticles Using <i>Passiflora edulis f. flavicarpa</i>

    摘要: The purpose of this study is to minimize the negative impacts of synthetic procedures and to develop environmentally benign procedures for the synthesis of metallic nanoparticles. In the present study, Passiflora edulis f. flavicarpa (P. edulis) aqueous leaf extract mediated green synthesis of silver nanoparticles are described. The synthesized silver nanoparticles were characterized by UV-Vis Spectroscopy, Fluorescence Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) Transmission Electron Microscopy (TEM) and Cyclic Voltammetry (CV). The silver nanoparticles (AgNPs) showed antibacterial activities against both gram positive (staphylococcus) and gram negative (Escherichia coli) bacteria. The efficacy of the synthesized silver nanoparticles (AgNPs) was demonstrated as catalyst in the photocatalytic degradation of Methyl Orange (MO) and Methylene Blue (MB) dyes which were measured spectrophotometrically. The study revealed that biosynthesized silver nanoparticles using Passiflora. edulis f. flavicarpa, plant extract was found to be very effective as antioxidant agent.

    关键词: Photocatalytic Activity,Green Synthesis,Silver Nanoparticles,Passiflora edulis f. flavicarpa,Antioxidant

    更新于2025-09-04 15:30:14