OPTICS EXPRESS
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2019
·Vol. 27
·期 17
·23981-23995
·
IF 3.561
Anxin Jiao,Hua Zhang,Linlin Xu,Yue Tian,Xiangdong Liu,Ming Chen,Feng Chen
The blue laser beam-excited surface-enhanced Raman scattering (SERS)-based pH sensing holds great promise for avoiding undesired thermal heating effect on some special temperature-vulnerable molecules, as compared to the vast majority studies by exciting in the red or near-infrared (NIR). Herein, we report an ingenious approach to support core-shell Au@Ag nanodendrites (NDs) on TiO2 nanowires, which can possess enhanced SERS activity under 473 nm laser excitation, owing to the improved charge-transfer effect on modified TiO2 support by inserting plasmonic Au@Ag. By using pH-indicating 4-mercaptobenzoic acid (4-MBA), the obtained TiO2/Au@Ag NDs can not only exhibit high sensitive linear-responses of pH changes ranging from pH 4.0 to 9.0 in different solutions (deionized water, NaCl, CaCl2, and MgCl2) but also provide excellent temperature stability under 4°C, 25°C and 37°C temperatures as well as good time stability after storage for 10 days. The established SERS-pH sensing by using shorter wavelength laser excitation is highly desirable for understanding physiological process in temperature-vulnerable microenvironment.
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高影响因子
ACS Sensors
·
2019
·
IF 6.944
Ziting Qian,Jiayuan Fei,Shenfei Zong,Kuo Yang,Lang Li,Ruiyang Liu,Zhuyuan Wang,Yiping Cui
A multifunctional microfluidic platform was demonstrated to monitor the interaction between tumor cells and endothelial cells by integrating a three-dimensional (3D) cell culture unit with a protein detection unit. In such a chip, breast cancer cells MCF7 were seeded into the collagen to form a 3D tumor environment while human umbilical vein endothelial cells (HUVECs) are seeded in the channel next to the collagen matrix. Thus, an in situ growth of angiogenic sprouting can be visualized through fluorescence in the 3D collagen matrix after a coculture of MCF7 and HUVEC after 4 days, which cannot be observed in the 2D culture environment. On the other hand, gold@silver core–shell nanorods were used as surface-enhanced Raman scattering (SERS) immunoprobes for the detection of the secretion of cytokine (vascular endothelial growth factor, VEGF). The limit of detection of the VEGF is 100 pg/mL. Further, as LiCl and bevacizumab can act as a promoter and an inhibitor of VEGF, the dynamic change of the concentration of VEGF under the stimulation of them was monitored by SERS signals. Thus, this integrated SERS microfluidic platform creates opportunity for the fundamental research of interaction between tumors and endothelial cells.
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MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-10
·
IF 5.479
Li Yue,Wang Yan,Wang Mingchao,Zhang Jinyue,Wang Qingwei,Li Hongji
In a new method for the determination of trace levels of chlorophenols in river waters, detection via surface-enhanced Raman scattering (SERS) is combined with recognition by a molecularly imprinted polymer (MIP). Nanoparticles of type Cu 2 O@Ag were synthesized by attaching silver particles to the surface of Cu 2 O nanoparticles. The Cu 2 O@Ag were then coated with a layer of a MIP that was obtained by atom transfer radical polymerization using from methacrylic acid as monomers and 2,6-dichlorophenol as the template. The morphology of Cu 2 O is found to be flower-like. The Cu 2 O@Ag-MIPs displays a strong SERS effect. Following removal of the template by rinsing with the mixture solution of methanol/acetic acid (9/1, v /v), the material was used to selectively bind 2,6-dichlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenol. The SERS peak intensity at 1580 cm −1 increases linearly with the concentration of the various chlorophenols in the range from 10 nM to 1 mM, and the detection limit is 5.8 nM. The imprinting factor is 4.62. The method was applied to the analysis of (spiked) river water, with recoveries ranging from 91.8 to 115.4% and relative standard deviations of <4.5%.
Graphical abstract
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2019
·
IF 2.931
Xingying Zhang,Ben Liu,Chenglong Hu,Shaoyun Chen,Xueqing Liu,Jiyan Liu,Fang Chen,Jian Chen,Fangyan Xie
Silver nanowires (i.e., AgNWs) can act as effective surface-enhanced Raman spectroscopy (i.e., SERS) substrates to detect small molecules. However, a lot of prepared AgNWs were often wrapped by polyvinylpyrrolidone (i.e., PVP) thin film to form an insulating layer to produce ill-defined AgNWs-PVP-AgNWs interface, limiting the plasmonic coupling among the stacked AgNWs. Herein, we reported a facile method in removal of PVP ligands from AgNWs for high performance and reusable SERS substrate. Sodium borohydride (NaBH 4 ) was used to completely remove the PVP ligands from the surface of AgNWs and produce a clean AgNWs-AgNWs interface that effectively enhances the localized surface plasmon resonance (i.e., LSPR) was produced, greatly improving the SERS activity of the AgNWs thin film. The SERS detection of rhodamine 6G (i.e., R6G) used with PVP AgNWs and without PVP AgNWs is 1.0 × 10 -9 and 1.0 × 10 -15 M, and the average enhancement factor ( EF ) is about 0.86 × 10 4 and 9.35 × 10 4 , respectively. Moreover, the recyclable behavior of the AgNWs with several analyte molecules is much more interesting than that of the PVP@AgNWs. The SERS detection of AgNWs for R6G, the 3-mercaptopropionic acid (i.e., 3-MPA) and melamine with good recyclability in nanomolar and millimolar concentration can be easily detected.
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TALANTA
·
2018
·
IF 4.244
Zhihua Zheng,Lei Wu,Lang Li,Shenfei Zong,Zhuyuan Wang,Yiping Cui
Accurate and quantitative analysis of breast cancer biomarkers is a particularly requisite in the early diagnosis of breast cancers, especially in real samples. Here, we develop a surface enhanced Raman scattering (SERS) immunoassay biosensor based on a microfluidic chip for the simultaneous detection of multiple breast cancer biomarkers in real samples. In such an immunoassay, immuno-Ag aggregates are labeled with different Raman reporters to detect multiple breast cancer biomarkers in real samples. Moreover, to better enhance the Raman signals, self-assembled silver nanoparticles are introduced on the bottom of the microfluidic channels to obtain the SERS active immune-substrate. In order to avoid the crosstalk of SERS signals, we designed a spatially separated detection biosensor by using multi-channels in a microfluidic chip. In the experiments, CA153, CA125 and CEA are selected as the models of breast cancer biomarkers, which can be simultaneously detected of in human serum with an excellently specificity and a high sensitivity. Furthermore, the proposed SERS microfluidic biosensor can be applied to detect the biomarkers in real samples using a linear regression method for the statistical analysis. Our detection results are in agreement with those obtained using commercial ELISA kits, which proves the reliability of our SERS-based microfluidic immunoassay.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Liyan Bi,Yunqing Wang,Ying Yang,Yuling Li,Shanshan Mo,Qingyin Zheng,Lingxin Chen
Conventional research on surface-enhanced Raman scattering (SERS)-based pH sensors often depends on nanoparticle aggregation, whereas the variability in nanoparticle aggregation gives rise to poor repeatability in the SERS signal. Herein, we fabricated a gold nanorod array platform via an efficient evaporative self-assembly method. The platform exhibits great SERS sensitivity with an enhancement factor of 5.6 × 107 and maintains excellent recyclability and reproducibility with relative standard deviation (RSD) values of less than 8%. On the basis of the platform, we developed a highly sensitive bovine serum albumin (BSA)-coated 4-mercaptopyridine (4-MPy)-linked (BMP) SERS-based pH sensor to report pH ranging from pH 3.0 to pH 8.0. The intensity ratio variation of 1004 and 1096 cm–1 in 4-MPy showed excellent pH sensitivity, which decreased as the surrounding pH increased. Furthermore, this BMP SERS-based pH sensor was employed to measure the pH value in C57BL/6 mouse blood. We have demonstrated that the pH sensor has great advantages such as good stability, reliability, and accuracy, which could be extended for the design of point-of-care devices.
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TALANTA
·
2018
·
IF 4.244
Tehseen Yaseen,Hongbin Pu,Da-Wen Sun
Fast sampling and multicomponent detections are important in the analysis of pesticide residues detection. In this work, surface-enhanced Raman scattering (SERS) method based on silver-coated gold nanoparticles (Au@Ag NPs) was used to simultaneously detect multi-class pesticide residues such as thiacloprid (carbamate), profenofos (organophosphate) and oxamyl (neonicotinoid) in standard solution and peach fruit. The Au@Ag NPs with 26 nm Au core size and 6 nm Ag shell thickness exhibited significant Raman enhancement, especially by the creation of hot spots through NPs aggregation induced by the connection between Au@Ag NPs and target molecules. The findings demonstrated that the characteristic wavenumber of the pesticides (thiacloprid, profenofos, and oxamyl) could be precisely identified using the SERS method. Compared with earlier studies, the current approach was rapid, inexpensive and without lengthy sample pretreatment. Moreover, the results revealed that the limit of detection (LOD) was 0.1 mg/kg for thiacloprid obtained in the peach extract with determination coefficient (R 2 ) of 0.986. Additionally, LOD for both profenofos and oxamyl was 0.01 mg/kg with a determination coefficient (R 2 ) of 0.985 and 0.988, respectively. Good recovery percentage (78.6–162.0%) showed the high SERS activity with better accuracy for the detection of the thiacloprid, profenofos, and oxamyl in peach. The results of this study could offer a promising SERS platform for simultaneous detection of other contaminants such as thiacloprid, profenofos and oxamyl in multifaceted food matrices.
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APPLIED SURFACE SCIENCE
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2018
·
IF 4.439
Chuhong Zhu,Xiaoye Hu,Xiujuan Wang
Surface-enhanced Raman scattering (SERS) is a promising analytical technique with molecular “fingerprint” characteristic and high sensitivity. To achieve high sensitivity, analytes should be located in or around the so-called SERS “hot spots” that are normally formed in sub-10 nm gaps between the neighboring plasmonic nanostructures. Ordinary SERS substrates generally show low sensitivity to the molecules that have weak affinity to noble-metal surfaces. Here, we fabricate an effective SERS system that can concentrate and adsorb organic pollutants in water for sensitive SERS detection. Such a SERS platform is composed of a thin film of Ag nanocubes/graphene oxide hybrid covered on a small Cu foil, and the Cu foil is placed on a hydrophobic teflon surface. The Ag nanocubes/graphene oxide hybrid film is synthesized by growth of graphene oxide on a Cu foil using electrophoresis and subsequent assembly of Ag nanocubes on the graphene oxide in ethanol via van der Waals interactions. Organic pollutant molecules can be concentrated on the hybrid film by adding a droplet of aqueous analyte solution on the hybrid film and evaporating. Due to the hydrophobic nature of teflon surface, the droplet will shrink onto the hybrid film and realize the concentration of analyte molecules on a SERS platform. There exists large delocalized π-electron system in the graphene oxide, so the Ag nanocubes/graphene oxide hybrid can effectively adsorb a large number of analyte molecules. As there are plenty of nano-sized gaps between the Ag nanocubes that are densely attached on the graphene oxide sheets, high density SERS hot spots can be formed in the gaps. As a result, the Ag nanocubes/graphene oxide hybrid has shown high SERS activity with an enhancement factor of 3.9 × 10 8 and good signal uniformity (relative standard deviation ∼12%). It is further demonstrated that the hybrid SERS substrates have exhibited high SERS sensitivity to organic pollutants such as 4-chlorobiphenyl and methyl parathion, showing promising applicability in many fields as diverse as chemical analysis, environmental monitoring, and food safety inspection.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Wen-Shu Zhang,Ya-Ning Wang,Yue Wang,Zhang-Run Xu
6-thioguanine is an anticancer drug with narrow safe dose range and intense toxic reactions, so it is urgently necessary to evaluate its clinical usage. Reproducibility and analysis speed are important factors to take into account when analyzing drug concentration in body fluids. In this work, we fabricated a droplet-based microfluidic chip for detecting 6-thioguanine in human serum by using the surface-enhanced Raman scattering (SERS) technique. The easily-prepared Au nanoparticles were used as SERS substrates, and reagent mixing and signal acquiring happened in droplets one by one. This assay device is endowed with the superiority in improving determination repeatability with coefficient of variation of no more than 5% (n = 25) and high speed of 10 s each assay. The SERS peak at 1295 cm −1 originated from N1-C6 stretching vibration mode of purine ring was selected for quantitating 6-thioguanine. The signals indicated a satisfied linear relationship with the concentrations of 6-thioguanine in the range of 0.010 μM to 10 μM, with a detection limit of 0.032 μM. The droplet-based microfluidic SERS system was successfully applied for credible and rapid analysis of 6-thioguanine in human serum, and is pretty promising for performing the therapeutic drug monitoring.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 4
·1-8
·
IF 5.705
Ren Xiaohui,Cheshari Emily C.,Qi Jingyao,Li Xin
An efficient approach is demonstrated for preparing particles consisting of a silver core and a shell of molecularly imprinted polymer (Ag@MIP). The MIP is prepared by using bisphenol A (BPA) as the template and 4-vinylpyridine as the functional monomer. The Ag@MIP fulfills a dual function in that the silver core acts as a SERS substrate, while the MIP allows for selective recognition of BPA. The Ag@MIP is characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, thermogravimetric analysis and Raman spectroscopy. The Raman intensity of Ag@MIP is higher than that of bare silver microspheres. The detection limit for BPA is as low as 10 −9 mol·L −1 .
Schematic illustration of the preparation of silver microspheres coated with a molecularly imprinted polymer (Ag@MIPs) for detecting bisphenol A (BPA) by surface enhanced Raman scattering (SERS).
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Lingfeng Wu,Weiwei Wu,Xiaolian Jing,Jiale Huang,Daohua Sun,Tareque Odoom-Wubah,Hongyu Liu,Haitao Wang,Qingbiao Li
The synthesis and applications of anisotropic nanostructures have attracted much attention in modern nanotechnology. Recently, biosynthesis has been demonstrated to be a viable green alternative to traditional chemical and physical methods for synthesizing metal nanostructures. Herein, we developed a new, green one-pot synthetic protocol in which silver nanoflowers (Ag NFs) with three-dimensional structures were synthesized by Canarium album foliar broths in the presence of trisodium citrate (TSC) at room temperature. The effects of silver nitrate, TSC, and foliar broths on these synthesis processes were investigated to determine the optimum synthesis conditions. Further exploration of the formation mechanism of Ag NFs showed that both the biomolecules and TSC played very important roles. The improved insight into the specific roles of the bioprotective components and the controlled synthesizing ability are expected to help explain the formation mechanism of this interesting nanostructure that exhibited an excellent performance in surface-enhanced Raman scattering.
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Journal of Materials Chemistry A
·
2013
·Vol. 1
·期 10
·3362-3371
·
IF 0
Yanyan Liu,Yunxia Zhang,Hualin Ding,Sichao Xu,Ming Li,Fengyu Kong,Yuanyuan Luo,Guanghai Li
Here, an oil-in-water emulsion method was used to assemble monodisperse noble metallic nanoparticles (NPs) in the oil phase into aggregates in the aqueous phase. The original size of the NPs is an essential factor in determining the final morphology: beyond the critical size, spherical aggregates with the original NPs can be formed; otherwise, complex aggregates with coarsing NPs come into being. The aggregation level of NPs and consequent properties of the as-constructed spherical assemblies can be optimized through tuning the evaporation rate of the organic solvent. The fabricated assemblies can serve as highly sensitive surface-enhanced Raman scattering (SERS) platforms for the detection of chemical or biological molecules, showing significantly high SERS activity toward rhodamine 6G (R6G) dye and 4-aminothiophenol (4-ATP) molecules. In addition, we further demonstrate the use of these highly sensitive SERS-active substrates to identify melamine at 1 × 10−7 M to insure food safety and biosecurity. Furthermore, the catalytic reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of excess NaBH4 was also investigated, in which the as-prepared silver assemblies exhibited excellent catalytic activities due to their special 3D architecture and large number of active catalytic sites.
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