RSC Advances
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2016
·Vol. 6
·期 79
·75384-75389
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IF 3.289
Liang-Liang Wu,Li-Ying Wang,Zheng-Jun Xie,Feng Xue,Chi-Fang Peng
This paper reported that the peroxidase-like activity of DNA–Ag/Pt nanoclusters (NCs) can be inhibited selectively by Hg2+. The interaction between Hg2+ and the DNA–Ag/Pt NCs was discussed through characterization by TEM, DLS and XPS, etc. It was found that the integration of both Hg0 and Hg2+ to the DNA–Ag/Pt NCs resulted in the DNA–Ag/Pt NCs aggregation and the decrease of Pt2+ content on the DNA–Ag/Pt NCs surface, which finally impaired their catalytic activity. Based on the above mechanism, a colorimetric detection for Hg2+ was developed with a detection limit (LOD) of 5.0 nM and a linear range from 10 nM to 200 nM. The method was highly selective toward Hg2+ over other common metal ions, low-cost and simple, which facilitated the application of detecting Hg2+ in tap water.
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BIOSENSORS & BIOELECTRONICS
·
2016
·
IF 7.476
Hang Ao,Zhaosheng Qian,Yuyu Zhu,Meizhi Zhao,Cong Tang,Yuanyuan Huang,Hui Feng,Aijun Wang
Due to the vital role of tyrosinase in melanin biosynthesis and its function as an important biomarker for melanoma cancer, highly sensitive detection of its activity using biocompatible materials is in urgent demand. Herein we report a convenient and highly sensitive fluorometric biosensor for tyrosinase activity detection based on biocompatible dopamine-functionalized Au/Ag nanoclusters (Dopa-Au/Ag NCs). Dopamine with redox property was covalently linked to Au/Ag NCs surface and formed a Dopa-Au/Ag NCs bioconjugate with strong blue fluorescence. Dopamine is readily oxidized by molecular oxygen under the catalysis of tyrosinase. After dopamine is transformed to o -dopaquinone, an intraparticle photoinduced election transfer (PET) process occurs between Au/Ag NCs and o -dopaquinone moiety, leading to the fluorescence quenching of the Dopa-Au/Ag NCs bioconjugate. Thus, this biosensor was utilized for sensitive and selective detection of tyrosinase in terms of the relationship between fluorescence quenching efficiency and tyrosinase activity. This study discovers that Au/Ag NCs and dopaquinone can serve as a good electron acceptor and donor pair which results in an efficient intraparticle photoinduced electron transfer process, and also provides another alternative way for tyrosinase activity monitoring.
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APPLIED THERMAL ENGINEERING
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2017
·
IF 3.444
Haoran Li,Yurong He,Ziyu Liu,Yimin Huang,Baocheng Jiang
Research in collection and conversion of solar energy has attracted an increasing interest because of the fact that conventional energy resources are becoming increasingly exhausted. For this reason, Ag@TiO 2 core–shell nanoparticles (NPs) with great absorptivity in the visible region were synthesized in this work. Subsequently, an experimental study on photo-thermal performances including steam generation and solar energy capture in a thermal receiver containing the Ag@TiO 2 NPs-based nanofluids was conducted. The effects of the NP concentration as well as the optical concentration were taken into consideration. The results showed that the nanofluids can be used for direct steam generation with a short period of solar irradiation time, even at the illumination intensity of 1 sun (1 sun = 1 kW/m 2 ). An evaporation efficiency of 53.6% can be achieved when the NP concentration is only 200 ppm owing to local heating induced by the surface plasmon resonance of the NPs. In addition, it is found that the nanofluid with a lower NP concentration has a higher temperature rise during illumination. Our findings also showed that the absorbed solar energy is transferred preferentially into latent heat enthalpy and consumed for steam generation instead of heating the nanofluids.
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RSC Advances
·
2016
·Vol. 6
·期 66
·61109-61118
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IF 3.289
Baowen Sun,Chunsheng Wang,Shuhua Han,Yongfeng Hu,Lijuan Zhang
A silver nanocube (Ag NC) nanoparticle-enhanced fluorescent nanocomposite was developed. The designed nanocomposite contained an Ag NC core of 50 nm in size as enhancer, the 10 nm silica interlayer, and outer shell-periodic mesoporous organosilicas (PMOs) which incorporated the bis(rhodamine Schiff-base derivative) siloxane groups. Little fluorescence emission of nanocomposites was observed due to the existence of spirolactam in the rhodamine derivative, however, upon the addition of Cu2+, the fluorescence emission intensity increased dramatically, which resulted from ring-opening of the spirolactam in the rhodamine moieties. We showed the effect of using an Ag NC core on the fluorescence emission intensity of the novel system. The emission intensity was approximately 3-fold higher for Ag-nanocube@SiO2@PMOs than the control sample prepared by etching the silver core away with iodide. Moreover, the metal-enhanced fluorescence (MEF) mechanism in this system was investigated through measuring the fluorescence lifetime. In addition, the designed core–shell Ag-nanocube@SiO2@PMOs nanocomposite could act as a sensitive and selective sensor to detect the Cu2+, and we have been expecting that the detection limit would be reduced by reaping benefits from the plasmon resonance of Ag NC core in this nanocomposite system.
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BIOSENSORS & BIOELECTRONICS
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2016
·
IF 7.476
Long Wu,Xiaoyan Xiao,Kun Chen,Wenmin Yin,Qin Li,Pan Wang,Zhicheng Lu,Jing Ma,Heyou Han
Abstrcact Highly sensitive and selective detection of specific DNA sequences is of great importance in clinical diagnosis, environmental and food monitoring, but it still remains challenges to develop a facile method for real sample detection in aqueous solution. Here, a simple and recyclable surface enhanced Raman scattering (SERS) sensor was constructed for Bacillus thuringiensis (Bt) special gene fragment detection by Fe 3 O 4 magnetic beads (MBs) and Au–Ag core-shell nanorods (Au@Ag NRs). A hairpin DNA with sulfhydryl and biotin was attached to Au@Ag NRs as indicator, and MBs with streptavidin (SA) were acted as the capture probe. On the basis of the biotin–SA specific interaction, target sequences were first hybridized with the hairpin DNA and exposed the biotin. Subsequently, the Au@Ag NRs were captured by the streptavidin modified MBs, which reduced the suspended NRs and led to the change of Raman intensity . Under the optimal conditions, the SERS intensity revealed a good linearity with Bt transgene fragment ranging from 0.1 pM to 1 nM with a detection limit of 0.14 pM (S/N=3). To demonstrate the specificity of the strategy, the single-base mismatch in DNA was discussed in the SERS assay. The results showed that the sensitivity and accuracy of the proposed method was acceptable in DNA detection, revealing a great potential in special gene detection.
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高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2017
·
IF 4.217
Meng Li,Zipeng Xing,Jiaojiao Jiang,Zhenzi Li,Junwei Yin,Junyan Kuang,Siyu Tan,Qi Zhu,Wei Zhou
A novel plasmonic Ag decorated S-TiO 2− x nanorods are successfully fabricated under 700 °C calcination, then followed by an in-situ solid-state chemical reduction approach with NaBH 4 in a mild calcination (350 °C) and combined with photo-deposition approach. The resultant Ag/S-TiO 2− x sample with high crystallinity and narrow band gap of ∼2.39 eV, extends the photoresponse to near-infrared region. The visible-light-driven photocatalytic degradation rate of phenol and hydrogen production rate for Ag/S-TiO 2− x nanorods are as high as 98.67% and 209.2 µmol h −1 g −1 , which is about 2 and 5 times higher than that of S-TiO 2 . Especially, first-order reaction rate constant of Ag/S-TiO 2− x nanorods is 14 times higher than that of S-TiO 2 . The excellent photocatalytic property can be attributed to the synergistic effect of Ti 3+ self-doping, S doping and the enhanced surface plasmon resonance of Ag nanoparticles, which narrows the band gap, favors the visible light utilization, and promotes the separation of photogenerated charge carriers.
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Journal of Materials Chemistry C
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2016
·Vol. 5
·期 6
·1402-1408
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IF 5.066
Yan Ke,Guowen Meng,Zhulin Huang,Ningning Zhou
For surface-enhanced Raman scattering (SERS)-based detection, it is desirable that the SERS substrates should not only have high SERS sensitivity, but also remarkable SERS-signal reproducibility and a good affinity for the target analytes. Herein, we report large-area membranes of plasmonic Ag-nanocubes (Ag-NCs) embedded in cellulose acetate (CA) microspheres (MSs) (denoted as Ag-NCs@CA-MSs), achieved by the electrospray technique, as highly sensitive and extremely homogeneous SERS substrates with good capture ability for analyte molecules in an aqueous solution. As a result, p-aminothiophenol (a probe molecule) and methyl parathion (a toxic pesticide) with concentrations down to 10−9 M and 10−7 M could be detected, respectively. Importantly, the membranes showed remarkable SERS-signal homogeneity over a large area, with a relative signal deviation down to 2.8% in a 500 × 500 μm2 area and 9.6% for the whole substrate (5 × 5 mm2). Moreover, Langmuir nonlinear fitting of the Raman intensity against the methyl parathion concentration was achieved, with a double-reciprocal plot of the Raman peak intensity versus the concentration showing a good linear relationship, making it possible for the quantitative SERS-based detection. Therefore, the Ag-NCs@CA-MS membranes showed potential for the quantitative SERS-based analysis of organic pollutants in the aqueous solution.
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RSC Advances
·
2014
·Vol. 5
·期 9
·6413-6418
·
IF 3.708
Hui Li,Guoping Zhang,Libo Deng,Rong Sun,Xing Ou-Yang
Thermally responsive copolymer P(NIPAm-co-NMA) was prepared via a radical copolymerization and spun into nanofibers using electrospinning. After thermal crosslinking, the electrospun fibers were modified using KH590 and silver nanoparticles were introduced onto the fiber surface using a chemical plating method. The electrical resistance of the composite fibers containing 65.5% of silver at different temperatures was investigated and it was found that the resistance dropped by ∼60% as the temperature increased from 42 °C to 46 °C, which is consistent with the solubility transition of PNIPAm with the change of temperature as revealed by differential scanning calorimetry (DSC) measurement.
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ANALYST
·
2014
·Vol. 140
·期 4
·1076-1081
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IF 3.906
Tianhua Li,Yonglong Li,Yujie Zhang,Chen Dong,Zheyu Shen,Aiguo Wu
Excessive uptake of NO2− is detrimental to human health, but the currently available methods used to sensitively detect this ion in the environment are cumbersome and expensive. In this study, we developed an improved NO2− detection system based on a redox etching strategy of CTAB-stabilized Ag–Au core–shell nanoparticles (Ag@AuNPs). The detection mechanism was verified by UV-Vis spectroscopy, TEM and XPS. The detection system produces a color change from purple to colorless in response to an increase of NO2− concentration. The selectivity of detection of NO2−, both with the unaided eye and by measurement of UV-Vis spectra, is excellent in relation to other ions, including Cu2+, Co2+, Ni2+, Cr3+, Al3+, Pb2+, Cd2+, Ca2+, Ba2+, Zn2+, Mn2+, Mg2+, Fe3+, Hg2+, Ag+, K+, F−, PO43−, C2O42−, SO32−, CO32−, SO42−, NO3− and CH3–COO− (Ac−). The limit of detection (LOD) for NO2− is 1.0 μM by eye and 0.1 μM by UV-Vis spectroscopy. The LOD by eye is lower than the lowest previously reported value (4.0 μM). There is a good linear relationship between A/A0 and the concentration of NO2− from 1.0 to 20.0 μM NO2−, which permits a quantitative assay. The applicability of our detection system was also verified by analysis of NO2− in tap water and lake water. The results demonstrate that our Ag@AuNP-based detection system can be used for the rapid colorimetric detection of NO2− in complex environmental samples, with excellent selectivity and high sensitivity.
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SENSORS AND ACTUATORS B-CHEMICAL
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2014
·
IF 3.84
Liu Tang,Yan Tong,Rongfeng Zheng,Weilu Liu,Yue Gu,Cong Li,Ruixue Chen,Zhiquan Zhang
A simple and novel electrochemical sensor was developed to determine levofloxacin based on the Ag nanoparticles/electrospun CeO 2 -Au composite nanofibers modified glassy carbon electrode (AgNPs/CeO 2 -Au/GCE). The electrospun CeO 2 -Au composite nanofibers provided a stable matrix and a large surface area for the fabrication of the sensing interface while the Ag nanoparticles dramatically promoted the current of levofloxacin on the electrode. Scanning electron microscopy and electrochemical methods were used to characterize the AgNPs/CeO 2 -Au composite film. The oxidative peak current was linear with the levofloxacin concentration in the range of 0.03–10 μM. The detection limit was as low as 0.01 μM ( S / N = 3), and the sensitivity could reach 1240 μA mM −1 cm −2 . Furthermore, the proposed modified electrode also could be feasibly applied to the determination of levofloxacin in human urine and blood serum samples.
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JOURNAL OF SUPERCRITICAL FLUIDS
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2014
·
IF 2.571
Qin-Qin Xu,Yu-Ling Ma,Gang-Xu,Jian-Zhong Yin,Ai-Qin Wang,Jin-Ji Gao
Well-defined Ag nanowires were obtained in SBA-15 at a short deposition time of 5 min in supercritical CO 2 when adding a small amount of ethylene glycol as the co-solvent. Ethylene glycol played a key role in dictating the nanowire morphology. Through detailed investigation of the whole deposition process, including the dissolution of precursor assisted by the co-solvent, the diffusion properties of the precursor into the nano-scale channels of the substrate, and the interaction between the precursor and the substrate, we found that a small amount of precursors were reduced into Ag 0 by ethylene glycol at the initial stage of the deposition. The resultant Ag 0 then acted as nuclei leading to a non-equilibrium sorption of the precursor. The rapid adsorption of the precursor onto the substrate resulted in a high loading of Ag in a short deposition time and the formation of nanowire morphology. Furthermore, this method was successfully extended to other porous substrates such as γ-Al 2 O 3 , SiO 2 and KIT-6, demonstrating its great potentials in the synthesis of nanocomposites.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Bobby Sebo,Niu Huang,Yumin Liu,Qidong Tai,Liangliang Liang,Hao Hu,Sheng Xu,Xing-Zhong Zhao
Light harvesting in dye-sensitized solar cells (DSSCs) mediated by plasmonic metallic nanoparticles and sub-micron light-scattering metal oxides is a facile and cost-effective approach to achieving high device performance. Ag nanoparticles , protected by thin shells of TiO 2 , were incorporated in TiO 2 photoanode. The large plasmonic near-field intensity generated by these nanoparticles caused an 18.3% rise in photocurrent , which resulted in an enhanced efficiency of 6.23% as compared to 5.29% efficiency of DSSC based on unmodified TiO 2 photoanode. In addition, DSSC with TiO 2 nanofibers (NFs) embedded in TiO 2 photoanode was also constructed, which because of the efficient light scattering ability of the nanofibers, attained an efficiency of 7.14% as a result of a current rise of 36.9%. Another DSSC was assembled with Ag NPs added to the photoanode of the NFs-based DSSC to further boost cell performance. The addition of Ag NPs, however, did not produce an appreciable change in the cell performance. The reason for this unexpected outcome was probably due to the low internal resistance associated with charge recombination and large resistance to electron transport in the cell as determined by electrochemical impedance analysis computed in this work.
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