SENSORS AND ACTUATORS B-CHEMICAL
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2014
·
IF 3.84
Jie Zhou,Liping Du,Ling Zou,Yingchang Zou,Ning Hu,Ping Wang
The fabrication of staphylococcal protein A (SPA) film on Au nanoparticle (AuNPs)-modified electrode was done for the construction of electrochemical immunosensor. In this work, a highly sensitive electrochemical immunosensor for the detection of a tumor biomarker, carcinoembryonic antigen (CEA) was developed by absorption of anti-CEA antibodies on the SPA-AuNPs modified gold electrode. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques were employed in the determination of electrode responses and applicability. Under the optimized condition, the immunosensor displays a good linear response to CEA with a range from 1 pg/ml to 100 ng/ml and a detection limit of 0.1 pg/ml. Furthermore, samples of 1–50 ng/ml CEA in rat serum was detected using the immunosensor and the immunosensor showed acceptable recoveries when the CEA value is within the scope of clinical detection. It can be concluded that the immunosensor provides a promising ultrasensitive immunology strategy for clinical diagnosis.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2014
·Vol. 90
·期 4
·678-685
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IF 2.494
Xiaolian Jing,Dengpo Huang,Huimei Chen,Tareque Odoom-Wubah,Daohua Sun,Jiale Huang,Qingbiao Li
BACKGROUND The synthesis and application of novel Au nanostructures are of increasing importance in modern nanotechnology. RESULTS Closely packed and chemically difficult-to-synthesize Au nanohorns (AuNHs) were synthesized in the presence of Escherichia coli cells (ECCs) and hexadecyltrimethylammonium chloride (CTAC) by a microorganism-mediated, CTAC-directed (MCD) approach. A proper ECC dosage, ascorbic acid (AA) and CTAC concentrations were essential for the growth of the AuNHs. In the formation mechanism of the AuNHs the ECCs surface acted as a platform for preferential nucleation and initial anisotropic growth of Au nanocrystals. As a result, some of the adjacent nanoparticles over the cell surface connected together via linear fusion to form dendritic nanostructures. Meanwhile, secondary nucleation in the solution gave rise to smaller nanoparticles that were consumed later on via Ostwald ripening during the formation of the AuNHs. Eventually, the two-dimensional film-like nanostructures between adjacent cells easily connected to form well-defined AuNHs with three-dimensional nanostructures. Interestingly, the AuNH/ECC composites can be used directly as sensitive surface-enhanced Raman spectroscopy (SERS) substrates for effective detection of 4-mercaptobenzoic acid (MBA). CONCLUSION The MCD strategy was an effective approach to novel AuNHs and AuNH/microorganism nanocomposites as SERS substrate. © 2014 Society of Chemical Industry
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Journal of Materials Chemistry C
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2015
·Vol. 3
·期 23
·6035-6045
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IF 4.696
Fan Zhang,Jian Zhu,Jian-Jun Li,Jun-Wu Zhao
The Ag coating-induced blue shift and enhancement of longitudinal plasmon of Au nanorods result in abundant and tunable optical absorptions in the visible region, which leads to the Au@Ag nanorod becoming a good candidate for colorimetric sensing. In this paper, we have reported an effective and simple approach for visualization detection of alpha-fetoprotein (AFP) based on Au@Ag core–shell nanorods. The AFP concentration-dependent colloid color of Au@Ag core–shell nanorods could change from green to gray, olivine to brown, and even blue to violet to pink, which are more varied color changes compared with the traditional red to blue color change. Besides, as the Ag shell thickness is increased, a dip was observed, which is located between two strong absorption peaks. The change of the dip is proposed as a new biosensor parameter for biomolecule detection based on absorption spectra. AFP concentration detection could be realized according to the change of the position and intensity of the dip, which has not been reported in the biomolecule detection field so far. Au@Ag core–shell nanorods with a small aspect ratio of inner Au nanorods are more suitable for direct read-out visualization, with a color change from blue to violet to pink. From the point of view of spectra analysis, Au@Ag core–shell nanorods with a greater aspect ratio of inner Au nanorods show higher spectral sensitivity. Furthermore, it is found that non-centrifuged Au@Ag core–shell nanorods are preferentially assembled in a side-by-side fashion with the addition of AFP, which will provide new approaches for other kinds of nanorods in controllable assembly fashions.
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TALANTA
·
2015
·
IF 3.545
Juan Li,Hangqing Xie,Yuhong Liu,Hang Ren,Wenbo Zhao,Xiaohua Huang
Nanomaterial-based signal-amplification strategies hold a great promise in realizing sensitive biological detection. A simple label-free electrochemical immunosensor for sensitive detection of carcinoembryonic antigen (CEA) was developed by immobilizing anti-CEA antibodies onto the Au-F127 strawberry-like nanospheres modified glassy carbon electrode (Au-F127/GCE). The Au-F127 strawberry-like nanospheres offered a large surface and multifunctional substrate for the effective immobilization of anti-CEA and the existence of Au could accelerate electron transfer and make the electrochemical signal amplified. The Au-F127 nanocomposites and anti-CEA were characterized by transmission electron microscopy (TEM), polycrystalline electron diffraction ring pattern, ultra-violet visible (UV–vis) spectra and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were employed to verify the stepwise assembly of the immunosensor and evaluated the analytical performance of the fabricated immunosensor, respectively. The immunosensor showed a wide liner response range between 0.01 and 80 ng mL −1 with a low detection limit of 0.24 pg mL −1 at a signal-to-noise (S/N) ratio of 3. Additionally, the proposed method was successfully applied to determine CEA in human serum samples with satisfactory results.
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高影响因子
Plasmonics
·
2015
·Vol. 11
·期 2
·565-572
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IF 2.238
Zhu Jian,Wang Jing-Fei,Li Jian-Jun,Zhao Jun-Wu
By using the fluorescence spectroscopic techniques, the fluorescence quenching abilities of gold triangular nanoplates with silver coating have been studied. Because of the surface plasmon resonance (SPR)-induced nonradiative energy transformation, the fluorescence emission intensity of carcinoembryonic antigen (CEA) could be greatly quenched by the silver-coated-gold triangular nanoplates. By comparing with the bare gold triangular nanoplates, the nanoplates with silver coating exhibit greater fluorescence quenching ability and could be further improved by increasing the coating thickness. The fluorescence quenching effect also depends on the concentration of CEA. For bare gold triangular nanoplates, the quenching ability to CEA is decreased as the CEA concentration is increased. Whereas for silver-coated-gold triangular nanoplates, the quenching ability to CEA is increased as the CEA concentration is increased. By analyzing the intensity quenching of the fluorescence peak, CEA could be detected with an ultra-low detection limit of 5 pg/mL.
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Journal of Physical Chemistry C
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2015
·
IF 4.772
Pu Liu,Huanjun Chen,Hao Wang,Jiahao Yan,Zhaoyong Lin,Guowei Yang
Nanoparticles of noble metals are typically plasmonic materials, but the pure metals have high nonirradiative ohmic losses at optical frequencies, leading to large absorption and unwanted heating effects. Additionally, spherical silicon nanoparticles (NPs) have a unique optical system with a high-refractive-index dielectric nanostructure. Combining these two components in one functional core/shell NP nanostructure of Si/M, where M represents a noble metal, to produce resonant optical electronic and magnetic responses has been rare. Herein, an approach for the assembly of Si/M core/shell NPs is developed on the basis of double-beam laser ablation in liquid, thereby fabricating a series of Si/M (M = Au, Ag, Pd, and Pt) core/shell NPs and characterizing the intense visible-light scattering modes from the as-fabricated Si/Au NPs as a nanoplasmonic structure. Dark-field optical measurements show that these Si/Au NPs have a strong electromagnetic response in the visible-light region, and the resonant frequencies can be modulated by NP size and morphology. The dispersed NPs are used as a highly sensitive surface-enhanced Raman scattering (SERS) active probe for detecting monolayer molecules, as proven herein using 4-MBT molecules. A SERS plasmonic enhancement factor of ∼108 is found for these Si/Au NPs by correlating the SERS measurement with scanning electron microscopy analysis. These findings present the possibility of confining light in ubiquitous silicon-based semiconductor technologies and manipulating the optical properties of nontraditional plasmonic nanostructures, while also opening new perspectives. This technique can be extended to other noble metals to form similar structures and fabricate low-loss metamaterials and nanophotonic devices.
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ACS Applied Materials & Interfaces
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2013
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IF 5.008
Shi Peng,Qiang Zheng,Xin Zhang,Linghui Dai,Jingxian Zhu,Yanbin Pi,Xiaoqing Hu,Wenqing Cheng,Chunyan Zhou,Yinlin Sha,Yingfang Ao
A disintegrin and metalloproteinase with thrombospondin motif-4 (ADAMTS-4) plays a pivotal role in degrading aggrecan, which is an early event in cartilage degrading joint diseases such as osteoarthritis (OA). Detection of ADAMTS-4 activity could provide useful clinical information for early diagnosis of such diseases and disease-modifying therapy. Therefore, we developed a ADAMTS-4 detective fluorescent turn-on AuNP probe (ADAMTS-4-D-Au probe) by conjugating gold nanoparticles with a FITC-modified ADAMTS-4-specific peptide (DVQEFRGVTAVIR). When the ADAMTS-4-D-Au probe was incubated with ADAMTS-4, the fluorescence recovered and fluorescence intensity markedly increased in proportion to concentrations of ADAMTS-4 and the probe. A nearly 3-fold increase in fluorescent intensity in response to only 3.9 pM of ADAMTS-4 was detected, whereas almost no fluorescence recovery was observed when the probe was incubated with matrix metalloproteinase (MMP)-1, -3, and -13. These results indicate a relative high sensitivity and specificity of the probe. Moreover, ADAMTS-4-D-Au probe was used to detect ADAMTS-4 activity in synovial fluid from 11 knee surgery patients. A substantial increase in fluorescent intensity was observed in the acute joint injury group as compared to the chronic joint injury and end-stage OA groups, indicating that this simple and low-cost sensing system might serve as a new detection method for ADAMTS-4 activity in biological samples and in screens for inhibitors for ADAMTS-4-related joint diseases. Additionally, this probe could be a potential biomarker for early diagnosis of cartilage-degrading joint diseases.
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高影响因子
Journal of Materials Chemistry A
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2015
·Vol. 4
·期 2
·466-477
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IF 7.443
Bo Li,Enyan Guo,Chengxiang Wang,Longwei Yin
We developed a facile strategy for the fabrication of uniform Au inlaid Zn2SnO4/SnO2 hollow rounded cubes with an adjustable Au loading content using ZnSn(OH)6 as the precursor, chloroauric acid as the Au source and ascorbic acid as the reducing agent. The Au inlaid Zn2SnO4/SnO2 hollow rounded cubes show enhanced light absorption ability and reduced recombination rate of photogenerated electron–hole pairs compared with pure Zn2SnO4/SnO2. The hollow rounded cube structured Au–Zn2SnO4/SnO2 sample displays a high surface area and high dye adsorption ability. As photoanodes for DSSCs, the Au–Zn2SnO4/SnO2 hollow rounded cubes demonstrate a greatly enhanced Jsc and an improved power conversion efficiency of up to 2.04%, almost 73% higher compared to the photovoltaic conversion efficiency of pure Zn2SnO4/SnO2 based DSSCs. The greatly improved power conversion efficiency of DSSCs based on the Au inlaid Zn2SnO4/SnO2 photoanode can be attributed to the following three factors. Firstly, the localized surface plasmon resonance of Au nanoparticles plays a crucial role in the enhancement of visible light absorption. Secondly, the potential barrier on the Zn2SnO4/SnO2 surface caused by Au nanoparticles can suppress electron–hole recombination, diminish the loss of electrons during the transfer process and improve the photocurrent density. Thirdly, the enhanced photovoltaic performance can also be attributed to the unique structural characteristics of hollow rounded cubes.
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ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Xuehui Pang,Jianxiu Li,Yongbei Zhao,Dan Wu,Yong Zhang,Bin Du,Hongmin Ma,Qin Wei
A high-sensitivity electrochemiluminescence (ECL) sensor was conducted to detect carcinoembryonic antigen (CEA). Nanocomposites of graphene oxide/carboxylated multiwall carbon nanotubes/gold/cerium oxide nanoparticles (GO/MWCNTs-COOH/Au@CeO2) were used as antibody carriers and sensing platforms to modify on glassy carbon electrodes (GCE). CeO2 nanoparticles were first exploited as an ECL luminescent material and the possible ECL mechanism was proposed in this work. GO/MWCNTs-COOH was used as a loading matrix for CeO2 nanoparticles because of the superior conductivity and large specific surface area. Au nanoparticles were further deposited on this matrix to attach anti-CEA and enhance the sensitivity of immunosensor. The proposed sensing platform showed excellent cathodic ECL performance and sensitive response to CEA. The effects of experimental conditions on the ECL performance were investigated. The proposed immunosensor showed the broad linear range (0.05–100 ng/mL) and the low detection limit (LOD, 0.02 ng/mL, signal-to-noise ratio = 3) according to the selected experimental conditions. The excellent analysis performance for determination of CEA in the human serum samples simplied this immunosensor displayed high sensitivity and excellent repeatability. More importantly, this conducted immunosensor broadens the use scope of CeO2 nanoparticles.
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高影响因子
ANALYST
·
2017
·Vol. 142
·期 16
·2936-2944
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IF 3.885
Jiamin Gao,Cheng Zhao,Zhuomin Zhang,Gongke Li
Reliable quantification by surface enhanced Raman scattering (SERS) highly depends on the development of a reproducible substrate with excellent anti-interference capability. In this work, an intrinsic internal standard (IS) SERS substrate based on a diblock copolymer, polystyrene-block-poly-4-vinylpyridine (PS-b-P4VP), as a template was developed by a modified block copolymer lithography (BCL) technique of reserving the diblock copolymer template. This substrate generated a stable vibration peak at 1066 cm−1 attributed to poly(4-vinylpyridine) (P4VP) which could be used as an intrinsic IS for precise SERS quantification. A series of characterization results showed that the diblock copolymer template endowed this substrate with homogeneous distribution of Au nanoparticles, excellent stability and reproducibility. A minor relative standard deviation (RSDs) of SERS responses at 1066 cm−1 was measured and calculated to be 4.3% from ten different substrates in the same batch, which suggested good substrate-to-substrate reproducibility of this substrate. Finally, this intrinsic IS substrate was successfully applied for the rapid quantification of a trace banned dye, chrysoidine, in food samples with complicated matrices by SERS. It was proved that chrysoidine could be found and quantified to be 0.50 and 0.41 mg L−1 in a positive dried bean curd stick and chilli powder sample respectively with good recoveries by this substrate coupled with SERS. The development of intrinsic IS substrates would benefit rapid and accurate quantification of trace targets in complex samples coupled with SERS analysis.
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TALANTA
·
2017
·
IF 4.162
Chi-Fang Peng,Na Pan,Qian Zhi-Juan,Xin-Lin Wei,Guang Shao
In this work, core-shell Au@Pt nanocatalysts (Au@Pt NCs) with ultrathin Pt shell were synthesized and demonstrated high peroxidase-like activity. Thiocyanate ions (SCN - ) were found to effectively inhibit the peroxidase-like activity of Au@Pt NCs, and the mechanism was discussed by the characterization of TEM , DLS, EPR and XPS, etc. The inhibition of the catalytic activity of Au@Pt NCs by SCN - was mainly due to the decreased ability of the Au@Pt NCs for capturing • OH radicals and the increased ratio of Pt 2+ to Pt° on the surface of the Au@Pt NCs. A sensitive colorimetric detection of thiocyanate (SCN - ) was developed, based on the activity inhibition of Au@Pt NCs by SCN - . Interestingly, cystine modification of Au@Pt NCs was found to significantly improve the selectivity of SCN - recognition. After optimization, a colorimetric assay for SCN - was established with a detection limit of 5.0 nM and a broad linear calibration over the range of 20 nM to 40 µM. This assay has the advantages of highly sensitive, selective and low-cost. Moreover, this assay demonstrated highly potential application in the quantitative determination of SCN - in water and raw milk samples.
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ACS Sustainable Chemistry & Engineering
·
2016
·
IF 5.267
Jiabai Cai,Xueqing Wu,Shunxing Li,Fengying Zheng
A new nanocomposite was reported as a good-performance photocatalyst, i.e., double-shelled, positively and negatively charged, nanostructured hollow spheres with supported Au nanoparticles (NPs). TiO2, WO3, and Au NPs were coated successively onto the functionalized polystyrene (PS) template spheres. The as-synthesized product PS@TiO2@WO3/Au nanocomposites were calcined at elevated temperature and then intact double-shelled TiO2@WO3/Au hollow spheres were obtained. The dispersity, morphology, size, and lattice of TiO2@WO3/Au hollow spheres were investigated by SEM and TEM. The presence of TiO2 hollow sphere and WO3/Au shell was proved by HAADF-STEM and XRD images. The photodegradation activity for rhodamine B and trimesic acid (i.e., color and colorless aromatic pollutants) in decreasing order were TiO2@WO3/Au, TiO2–WO3, P25. Under visible-light irradiation, the photodegradation rate of rhodamine B and trimesic acid for TiO2@WO3/Au was 94% and 95%, respectively, which exhibited a significant increase of 62% and 80% as compared with P25. The synergistic effect of coupling TiO2 hollow spheres with WO3 shell and Au NPs on photocatalytic performance was proved by this article. First, Au NPs deposited in WO3 shell and loaded on TiO2 shell separately act as electron trap site and surface plasmon resonance-sensitizer, respectively, and hence the photogenerated electron–hole separation rate was improved. Second, the visible-light absorption of TiO2 hollow spheres was increased by the coexistence of WO3 and Au and unique hierarchical mesoporous architectures of TiO2@WO3/Au. Finally, the surface charge of TiO2@WO3/Au and rhodamine B was negative and positive, respectively, the affinity between them could be improved by electrical attractions, and then the major bottleneck in heterogeneous photocatalysis (i.e., poor affinity between pollutants and photocatalyst) could be broken. The optimal hollow sphere size of TiO2@WO3/Au was 450 nm, which was proved by the photodegradation of aromatic pollutants and photoreduction of Cr(VI).
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