For the first time, Mo nanoscrew was cultivated as a novel non-coinage-metal substrate for surface-enhanced Raman scattering(SERS). It was found that the nanoscrew is composed of many small screw threads stacking alon...For the first time, Mo nanoscrew was cultivated as a novel non-coinage-metal substrate for surface-enhanced Raman scattering(SERS). It was found that the nanoscrew is composed of many small screw threads stacking along its length direction with small separations. Under external light excitation, strong electromagnetic coupling was initiated within the gaps, and many hot-spots formed on the surface of the nanoscrew, which was confirmed by high-resolution scanning near-field optical microscope measurements and numerical simulations using finite element method. These hotspots are responsible for the observed SERS activity of the nanoscrews. Raman mapping characterizations further revealed the excellent reproducibility of the SERS activity. Our findings may pave the way for design of low-cost and stable SERS substrates.展开更多
We describe the synthesis of three-dimensional(3D) multilayer ZnO@Ag/SiO2@Ag nanorod arrays by the physico–chemical method. The surface-enhanced Raman scattering(SERS) performance of the 3D multilayer Zn O@Ag/SiO2@Ag...We describe the synthesis of three-dimensional(3D) multilayer ZnO@Ag/SiO2@Ag nanorod arrays by the physico–chemical method. The surface-enhanced Raman scattering(SERS) performance of the 3D multilayer Zn O@Ag/SiO2@Ag nanorod arrays is studied by varying the thickness of dielectric layer SiO2 and outer-layer noble Ag. The 3D Zn O@Ag/SiO2@Ag nanorod arrays create a huge number of SERS "hot spots" that mainly contribute to the high SERS sensitivity. The great enhancement of SERS results from the electron transfer between ZnO and Ag and different electromagnetic enhancements of Ag nanoparticles(NPs) with different thicknesses. Through the finite-difference time-domain(FDTD) theoretical simulation, the enhancement of SERS signal can be ascribed to a strong electric field enhancement produced in the 3D framework. The simplicity and generality of our method offer great advantages for further understanding the SERS mechanism induced by the surface plasmon resonance(SPR) effect.展开更多
Surface-enhanced resonance Raman scattering(SERRS)has recently attracted great interest in analytical science due toenormous enhancement factors that have decreased the detec-tionli mits of a wide variety of molecules...Surface-enhanced resonance Raman scattering(SERRS)has recently attracted great interest in analytical science due toenormous enhancement factors that have decreased the detec-tionli mits of a wide variety of molecules to the single moleculelevel.The SERRS-electromagnetic(EM)model describessingle-molecule SERRS展开更多
Raman spectrum is a powerful analytical tool for determining the chemical information of compounds. In this study, we obtained analytical results of chlorophenols(CPs) molecules including 4-chlorophenol(4-CP), 2,6-dic...Raman spectrum is a powerful analytical tool for determining the chemical information of compounds. In this study, we obtained analytical results of chlorophenols(CPs) molecules including 4-chlorophenol(4-CP), 2,6-dich- lorophenol(2,6-DCP) and 2,4,6-trichlorophenol(2,4,6-TCP) on the surface of Ag dendrites by surface-enhanced Raman scattering(SERS) spectra. SEM images indicate that the SERS substrate of Ag dendrites is composed of a large number of polygonal nanocrystallites, which self-assembled into a 3D hierarchical structure. It was found that there were distinct differences for those three molecules from Raman and SERS spectra. This indicates that SERS could be a new tool of detection technique regarding trace amounts of CPs.展开更多
Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet(CV) and malachite green(MG),were accomplished by surface-enhanced Raman scattering(SERS). Based on the optimized Au/cicada wing, the de...Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet(CV) and malachite green(MG),were accomplished by surface-enhanced Raman scattering(SERS). Based on the optimized Au/cicada wing, the detectable concentration of CV/MG can reach 10^(-7) M, and the linear logarithmic quantitative relationship curves between log I and log C allows for the determination of the unknown concentration of CV/MG solution. The detection of these two analytes in real environment was also achieved, demonstrating the application potential of SERS in the fast screening of the prohibited fish drugs, which is of great benefit for food safety and environmental monitoring.展开更多
We proposed a facile and rapid method for preparing silica-silver core-shell(SSCS) substrates to use Ag electroless plating on SiO2@Au-seed particles.UV-Vis-NIR absorption spectrometer and SEM were employed to monitor...We proposed a facile and rapid method for preparing silica-silver core-shell(SSCS) substrates to use Ag electroless plating on SiO2@Au-seed particles.UV-Vis-NIR absorption spectrometer and SEM were employed to monitor the reaction process of the formation of Ag on the surfaces of silica beads,and the optical resonance of the substrate could shift from visible to NIR region.It has been found that surface-enhanced Raman scattering(SERS) enhancement changes with the electroless plating time and the SSCS substrate with the plating time of 90 s(90SSCS) shows the strongest SERS response under the laser excitation at 514.5 nm.Signals collected over multiple spots and substrate of rhodamine 6G(R6G) resulted in a relative standard deviation(RSD) of 9.75%.The calculated enhancement factor(EF) was approximately 105 "106.SSCS substrate exhibits high SERS performance,which is due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO2 nanoparticles.And this substrate presents tunable and broad localized surface plasmon resonance(LSPR),so this method may open a new way for SERS studies with other laser excitation.展开更多
Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induc...Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation.The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy.The enhancement of Raman scattering for two model molecules (2-naphthalenethiol and rhodamine 6G) is about 5-6 orders of magnitude.By changing the aspect ratio of the Au nanorods,we found that the enhancement factors decreased with the increase of aspect ratios.The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods,which may result in huge local electromagnetic field enhancements in those confined junctions.展开更多
Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' pote...Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' potential in the field of tribology and their application in ultra-charge/discharge devices. In this paper, a novel surface-enhanced Raman scattering technique that involves coating the sample with nanoscopic gold particles is proposed to characterize the NDs after different annealing treatments. Conventional Raman and surfaceenhanced Raman spectra were obtained, and the changes of peak parameters as the function of annealing temperature were evaluated. It was found that the widths of the D and the G peaks decreased with increasing annealing temperature, reflecting an improved order in the sp^2-hybridized carbon during the transformation from NDs to carbon onions. After annealing at 1700 ℃, the sp^2?carbon was highly ordered, indicating desirable electrical conductivity and lubricity. With increasing annealing temperature, the D peak showed a blue shift of almost30 cm^(-1), while the G peak merely shifted by 5 cm^(-1). For annealing temperatures above 1100 ℃, an increase of intensity ratio ID/IGwas observed. Compared to the uncoated area, red shifts of 0.5-2 cm^(-1) and of 5-9 cm^(-1) for the G and D peaks, respectively, were detected for the gold-coated area, which was due to the coupling of the plasmons and the phonons of the samples.展开更多
Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of t...Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials (NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine 6G (R6G, 1×10-10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS signal.展开更多
A self\|assembled monolayer film(SAM) of ruthenium phthalocyanine(RuPc) fabricated on a silver substrate premodified with an SAM of terephthalonitrile(TPN) was studied by means of surface\|enhanced Raman scattering(SE...A self\|assembled monolayer film(SAM) of ruthenium phthalocyanine(RuPc) fabricated on a silver substrate premodified with an SAM of terephthalonitrile(TPN) was studied by means of surface\|enhanced Raman scattering(SERS) and ultraviolet\|visible(UV\|Vis) spectroscopies. TPN was used as a ligand to link RuPc since it can not only modify the silver substrate but also deliver the nitrile groups protruding from the silver surface. Therefore,we can explore the relationship between the structure and the orientation of RuPc and the TPN\|modified substrate. The UV\|Vis spectra indicate a strong interaction between RuPc and TPN in the composite film. The result is further confirmed by the SERS spectra of RuPc\|TPN SAM,in which the vibrational bands arising from both the RuPc and TPN moieties appear clearly,indicating that the RuPc is successfully assembled on the TPN film.展开更多
A large-scale Si nanowire array(SiNWA) is fabricated with gold(Au) nanoparticles by simple metal-assisted chemical etching and metal reduction processes. The three-dimensional nanostructured Au/SiNWA is evaluated as a...A large-scale Si nanowire array(SiNWA) is fabricated with gold(Au) nanoparticles by simple metal-assisted chemical etching and metal reduction processes. The three-dimensional nanostructured Au/SiNWA is evaluated as an active substrate for surface-enhanced Raman scattering(SERS). The results show that the detection limit for rhodamine 6G is as low as10-7M, and the Raman enhancement factor is as large as 105with a relative standard deviation of less than 25%. After the calibration of the Raman peak intensities of rhodamine 6G and thiram, organic molecules could be quantitatively detected.These results indicate that Au/SiNWA is a promising SERS-active substrate for the detection of biomolecules present in low concentrations. Our findings are an important advance in SERS substrates to allow fast and quantitative detection of trace organic contaminants.展开更多
Surface-enhanced Raman scattering(SERS) spectra of different silver nanoplate self-assembled films at different excitation wavelengths were fairly compared.Shape conversion from silver nanoprisms to nanodisks on slide...Surface-enhanced Raman scattering(SERS) spectra of different silver nanoplate self-assembled films at different excitation wavelengths were fairly compared.Shape conversion from silver nanoprisms to nanodisks on slides was in situ carried out.The SERS spectra of 4-mercaptopyridine(4-MPY) on these anisotropic silver nanoparticle self-assembled films present that strong enhancement appeared when the excitation line and the surface plasmon resonance(SPR) band of silver substrate overlapped.In this model,the influence of the crystal planes of silver nanoplates on SERS enhancement could be ignored because the basal planes were nearly unchanged in two kinds of silver nanoplate self-assembled films.展开更多
In this paper, a novel surface-enhanced Raman scattering (SERS) sensor combined with fused biconical taper fiber (FBTF) and film coated with silver sols is proposed. This structure is designed to significantly increas...In this paper, a novel surface-enhanced Raman scattering (SERS) sensor combined with fused biconical taper fiber (FBTF) and film coated with silver sols is proposed. This structure is designed to significantly increase the SERS active surface when the length of the taper is increased and the radius is reduced, since the penetration depth is inversely proportional to the taper radius and proportional to the taper length according to the fiber-optic evanescent-wave theory. Based on the SERS sensing principle, the feasibility of FBTF sensor is analyzed in this paper. As a result, the Raman spectrum of R6G is obtained from the fused biconical taper zone surface coating with the silver sols in our experiments. The detected concentration is up to 10?7mol/L.展开更多
With the continuous discovery and research of predictive cancer-related biomarkers,liquid biopsy shows great potential in cancer diagnosis.Surface-enhanced Raman scattering(SERS)and microfluidic technology have receiv...With the continuous discovery and research of predictive cancer-related biomarkers,liquid biopsy shows great potential in cancer diagnosis.Surface-enhanced Raman scattering(SERS)and microfluidic technology have received much attention among the various cancer biomarker detection methods.The former has ultrahigh detection sensitivity and can provide a unique fingerprint.In contrast,the latter has the characteristics of miniaturization and integration,which can realize accurate control of the detection samples and high-throughput detection through design.Both have the potential for point-of-care testing(POCT),and their combination(lab-on-a-chip SERS(LoC-SERS))shows good compatibility.In this paper,the basic situation of circulating proteins,circulating tumor cells,exosomes,circulating tumor DNA(ctDNA),and microRNA(miRNA)in the diagnosis of various cancers is reviewed,and the detection research of these biomarkers by the LoC-SERS platform in recent years is described in detail.At the same time,the challenges and future development of the platform are discussed at the end of the review.Summarizing the current technology is expected to provide a reference for scholars engaged in related work and interested in this field.展开更多
Phosphorylation of tau at Ser(396,404)(p-tau^(396,404))is one of the earliest phosphorylation events,plasma p-tau^(396,404) level appears to be a potentially promising biomarker of Alzheimer’s disease(AD).The low abu...Phosphorylation of tau at Ser(396,404)(p-tau^(396,404))is one of the earliest phosphorylation events,plasma p-tau^(396,404) level appears to be a potentially promising biomarker of Alzheimer’s disease(AD).The low abundance and easy degradation of p-tau in the plasma make the lateral flow assay(LFA)a suitable choice for point-of-care detection of plasma p-tau^(396,404) levels.Herein,based on our screening of a pair of p-tau^(396,404)-specific antibodies,we developed a colorimetric and surface-enhanced Raman scattering(SERS)dual-readout LFA for the rapid,highly sensitive,robust detection of plasma p-tau^(396,404) levels.This LFA realized a detection limit of 60 pg/mL by the naked eye or 3.8 pg/mL by SERS without cross-reacting with other tau species.More importantly,LFA rapidly and accurately differentiated AD patients from healthy controls,suggesting that it has the potential for clinical point-of-care application in AD diagnosis.This dual-readout LFA has the advantages of simple operation,rapid,ultra-sensitive detection,providing a new way for early AD diagnosis and intervention,especially in primary and community AD screening.展开更多
Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of M...Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of MoS_(2)-Ag nanocomposites via laser-assisted photoreduction was proposed.For the photoreduction process,we used AgNO_(3)solution as a metal source.Under laser irradiation,Ag ions were easily reduced on MoS_(2)by photo-generated electrons from MoS_(2).The optical properties of MoS_(2)-Ag nanocomposites were easily controlled by simple adjustment of the photoreduction time.To investigate the surface-enhanced Raman scattering(SERS)effect of the MoS_(2)-Ag nanocomposites,the SERS spectra of methylene blue(MB)on MoS_(2)-Ag nanocomposites were measured,and the nanocomposites were found to enhance the Raman scattering intensity of MB up to~106.Therefore,the laser-assisted photoreduction method has great potential for rapid synthesis and optical tuning of semiconductoremetal nanocomposites.展开更多
Surface-enhanced Raman scattering(SERS)has been used in atmospheric aerosol detection as it enables the high-resolution analysis of particulate matter.However,its use in the detection of historical samples without dam...Surface-enhanced Raman scattering(SERS)has been used in atmospheric aerosol detection as it enables the high-resolution analysis of particulate matter.However,its use in the detection of historical samples without damaging the sampling membrane while achieving effective transfer and the high-sensitivity analysis of particulate matter from sample films remains challenging.In this study,a new type of SERS tape was developed,consisting of Au nanoparticles(NPs)on an adhesive double-sided Cu film(DCu).The enhanced electromagnetic field generated by the coupled resonance of the local surface plasmon resonances of AuNPs and DCu led to an enhanced SERS signal with an experimental enhancement factor of 10^(7).The AuNPs were semi-embedded and distributed on the substrate,and the viscous DCu layer was exposed,enabling particle transfer.The substrates exhibited good uniformity and favorable reproducibility with relative standard deviations of 13.53%and 9.74%respectively,and the substrates could be stored for 180 days with no signs of signal weakening.The application of the substrates was demonstrated by the extraction and detection of malachite green and ammonium salt particulate matter.The results demonstrated that SERS substrates based on AuNPs and DCu are highly promising in real–world environmental particle monitoring and detection.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11474364,51202300,51290271)the National Key Basic Research Program of China(Grant Nos.2013CB933601,2013YQ12034506)+3 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar(Grant No.2014A030306017)the Guangdong Special Support Program,the Doctoral Fund of Ministry of Education of China(Grant No.20120171120012)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT13042)the Fundamental Research Funds for the Central Universities
文摘For the first time, Mo nanoscrew was cultivated as a novel non-coinage-metal substrate for surface-enhanced Raman scattering(SERS). It was found that the nanoscrew is composed of many small screw threads stacking along its length direction with small separations. Under external light excitation, strong electromagnetic coupling was initiated within the gaps, and many hot-spots formed on the surface of the nanoscrew, which was confirmed by high-resolution scanning near-field optical microscope measurements and numerical simulations using finite element method. These hotspots are responsible for the observed SERS activity of the nanoscrews. Raman mapping characterizations further revealed the excellent reproducibility of the SERS activity. Our findings may pave the way for design of low-cost and stable SERS substrates.
基金Project supported by the Fund from the Science and Technology Department of Jilin Province,China(Grant No.20170520108JH)the Beihua University Youth Nurtural Fund,China(Grant No.2017QNJJL15)+1 种基金the Beihua University PhD Research Start-up Fund,China(Grant No.202116140)the Undergraduate Innovation Project,China(Grant No.220718100)
文摘We describe the synthesis of three-dimensional(3D) multilayer ZnO@Ag/SiO2@Ag nanorod arrays by the physico–chemical method. The surface-enhanced Raman scattering(SERS) performance of the 3D multilayer Zn O@Ag/SiO2@Ag nanorod arrays is studied by varying the thickness of dielectric layer SiO2 and outer-layer noble Ag. The 3D Zn O@Ag/SiO2@Ag nanorod arrays create a huge number of SERS "hot spots" that mainly contribute to the high SERS sensitivity. The great enhancement of SERS results from the electron transfer between ZnO and Ag and different electromagnetic enhancements of Ag nanoparticles(NPs) with different thicknesses. Through the finite-difference time-domain(FDTD) theoretical simulation, the enhancement of SERS signal can be ascribed to a strong electric field enhancement produced in the 3D framework. The simplicity and generality of our method offer great advantages for further understanding the SERS mechanism induced by the surface plasmon resonance(SPR) effect.
文摘Surface-enhanced resonance Raman scattering(SERRS)has recently attracted great interest in analytical science due toenormous enhancement factors that have decreased the detec-tionli mits of a wide variety of molecules to the single moleculelevel.The SERRS-electromagnetic(EM)model describessingle-molecule SERRS
基金Supported by the National Natural Science Foundation of China(Nos.21073072, 20903044)the Scientific and Technological Development Plan Project of Jilin Province, China(No.20090546)+1 种基金the Open Project of State Key Laboratory of Superhard Materials, Chinathe Basic Research Fund of Jilin University, China
文摘Raman spectrum is a powerful analytical tool for determining the chemical information of compounds. In this study, we obtained analytical results of chlorophenols(CPs) molecules including 4-chlorophenol(4-CP), 2,6-dich- lorophenol(2,6-DCP) and 2,4,6-trichlorophenol(2,4,6-TCP) on the surface of Ag dendrites by surface-enhanced Raman scattering(SERS) spectra. SEM images indicate that the SERS substrate of Ag dendrites is composed of a large number of polygonal nanocrystallites, which self-assembled into a 3D hierarchical structure. It was found that there were distinct differences for those three molecules from Raman and SERS spectra. This indicates that SERS could be a new tool of detection technique regarding trace amounts of CPs.
基金Project supported by the National Basic Research Program of China(Grant No.2014CB745100)the National Natural Science Foundation of China(Grant Nos.21390202 and 21676015)the Beijing Higher Education Young Elite Teacher Project
文摘Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet(CV) and malachite green(MG),were accomplished by surface-enhanced Raman scattering(SERS). Based on the optimized Au/cicada wing, the detectable concentration of CV/MG can reach 10^(-7) M, and the linear logarithmic quantitative relationship curves between log I and log C allows for the determination of the unknown concentration of CV/MG solution. The detection of these two analytes in real environment was also achieved, demonstrating the application potential of SERS in the fast screening of the prohibited fish drugs, which is of great benefit for food safety and environmental monitoring.
基金Supported by the National Natural Science Foundation of China(Nos.20873050,20921003,20973074,20903044)the "111" Project(No.B06009)the Key Projects in the National Science & Technology Pillar Program,China(No.2007BAI38B03)
文摘We proposed a facile and rapid method for preparing silica-silver core-shell(SSCS) substrates to use Ag electroless plating on SiO2@Au-seed particles.UV-Vis-NIR absorption spectrometer and SEM were employed to monitor the reaction process of the formation of Ag on the surfaces of silica beads,and the optical resonance of the substrate could shift from visible to NIR region.It has been found that surface-enhanced Raman scattering(SERS) enhancement changes with the electroless plating time and the SSCS substrate with the plating time of 90 s(90SSCS) shows the strongest SERS response under the laser excitation at 514.5 nm.Signals collected over multiple spots and substrate of rhodamine 6G(R6G) resulted in a relative standard deviation(RSD) of 9.75%.The calculated enhancement factor(EF) was approximately 105 "106.SSCS substrate exhibits high SERS performance,which is due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO2 nanoparticles.And this substrate presents tunable and broad localized surface plasmon resonance(LSPR),so this method may open a new way for SERS studies with other laser excitation.
基金Project supported by the National Natural Science Foundation of China (Grant No.50872147)the National High Technology Research and Development Program of China (Grant No.2007AA03Z305)the Special Doctoral Foundation of the Ministry of Education of China (Grant No.20775030)
文摘Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation.The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy.The enhancement of Raman scattering for two model molecules (2-naphthalenethiol and rhodamine 6G) is about 5-6 orders of magnitude.By changing the aspect ratio of the Au nanorods,we found that the enhancement factors decreased with the increase of aspect ratios.The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods,which may result in huge local electromagnetic field enhancements in those confined junctions.
基金supported by National Natural Science Foundation of China (No. 51575389, 51761135106, 51511130074)National Key Research and Development Program of China (2016YFB1102203)State key laboratory of precision measuring technology and instruments (Pilt1705)
文摘Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' potential in the field of tribology and their application in ultra-charge/discharge devices. In this paper, a novel surface-enhanced Raman scattering technique that involves coating the sample with nanoscopic gold particles is proposed to characterize the NDs after different annealing treatments. Conventional Raman and surfaceenhanced Raman spectra were obtained, and the changes of peak parameters as the function of annealing temperature were evaluated. It was found that the widths of the D and the G peaks decreased with increasing annealing temperature, reflecting an improved order in the sp^2-hybridized carbon during the transformation from NDs to carbon onions. After annealing at 1700 ℃, the sp^2?carbon was highly ordered, indicating desirable electrical conductivity and lubricity. With increasing annealing temperature, the D peak showed a blue shift of almost30 cm^(-1), while the G peak merely shifted by 5 cm^(-1). For annealing temperatures above 1100 ℃, an increase of intensity ratio ID/IGwas observed. Compared to the uncoated area, red shifts of 0.5-2 cm^(-1) and of 5-9 cm^(-1) for the G and D peaks, respectively, were detected for the gold-coated area, which was due to the coupling of the plasmons and the phonons of the samples.
基金Project(10804101) supported by the National Natural Science Foundation of ChinaProject(2007CB815102) supported by the National Basic Research Program of ChinaProject(2007B08007) supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials (NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine 6G (R6G, 1×10-10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS signal.
文摘A self\|assembled monolayer film(SAM) of ruthenium phthalocyanine(RuPc) fabricated on a silver substrate premodified with an SAM of terephthalonitrile(TPN) was studied by means of surface\|enhanced Raman scattering(SERS) and ultraviolet\|visible(UV\|Vis) spectroscopies. TPN was used as a ligand to link RuPc since it can not only modify the silver substrate but also deliver the nitrile groups protruding from the silver surface. Therefore,we can explore the relationship between the structure and the orientation of RuPc and the TPN\|modified substrate. The UV\|Vis spectra indicate a strong interaction between RuPc and TPN in the composite film. The result is further confirmed by the SERS spectra of RuPc\|TPN SAM,in which the vibrational bands arising from both the RuPc and TPN moieties appear clearly,indicating that the RuPc is successfully assembled on the TPN film.
基金supported by the National Natural Science Foundation of China(Grant No.11104008)the Beijing Natural Science Foundation,China(Grant No.4142040)+2 种基金the Doctoral Fund of the Ministry of Education of China(Grant No.20090010120014)the Beijing Higher Education Young Elite Teacher Projectthe Technology Research and Development Program of Qinhuangdao City,China(Grant Nos.201001A034 and 2012021A056)
文摘A large-scale Si nanowire array(SiNWA) is fabricated with gold(Au) nanoparticles by simple metal-assisted chemical etching and metal reduction processes. The three-dimensional nanostructured Au/SiNWA is evaluated as an active substrate for surface-enhanced Raman scattering(SERS). The results show that the detection limit for rhodamine 6G is as low as10-7M, and the Raman enhancement factor is as large as 105with a relative standard deviation of less than 25%. After the calibration of the Raman peak intensities of rhodamine 6G and thiram, organic molecules could be quantitatively detected.These results indicate that Au/SiNWA is a promising SERS-active substrate for the detection of biomolecules present in low concentrations. Our findings are an important advance in SERS substrates to allow fast and quantitative detection of trace organic contaminants.
基金Supported by the National Natural Science Foundation of China(Nos.91027010,21073073,20903043,20973075,20773045)the Research Fund for the Doctoral Program of Higher Education of China(No.20090061120089)the Open Project of State Key Laboratory for Supramolecular Structure and Materials of China(No.201125)
文摘Surface-enhanced Raman scattering(SERS) spectra of different silver nanoplate self-assembled films at different excitation wavelengths were fairly compared.Shape conversion from silver nanoprisms to nanodisks on slides was in situ carried out.The SERS spectra of 4-mercaptopyridine(4-MPY) on these anisotropic silver nanoparticle self-assembled films present that strong enhancement appeared when the excitation line and the surface plasmon resonance(SPR) band of silver substrate overlapped.In this model,the influence of the crystal planes of silver nanoplates on SERS enhancement could be ignored because the basal planes were nearly unchanged in two kinds of silver nanoplate self-assembled films.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61027015, 60677031, 60937003)the Shanghai Leading Academic Discipline Project (Grant No.30108)the Science and Technology Commission of Shanghai Municipality (Grant No.10DZ2210900)
文摘In this paper, a novel surface-enhanced Raman scattering (SERS) sensor combined with fused biconical taper fiber (FBTF) and film coated with silver sols is proposed. This structure is designed to significantly increase the SERS active surface when the length of the taper is increased and the radius is reduced, since the penetration depth is inversely proportional to the taper radius and proportional to the taper length according to the fiber-optic evanescent-wave theory. Based on the SERS sensing principle, the feasibility of FBTF sensor is analyzed in this paper. As a result, the Raman spectrum of R6G is obtained from the fused biconical taper zone surface coating with the silver sols in our experiments. The detected concentration is up to 10?7mol/L.
基金supported by the Natural Science Foundation of Hunan Province,China(Grant No.:2021JJ80078).
文摘With the continuous discovery and research of predictive cancer-related biomarkers,liquid biopsy shows great potential in cancer diagnosis.Surface-enhanced Raman scattering(SERS)and microfluidic technology have received much attention among the various cancer biomarker detection methods.The former has ultrahigh detection sensitivity and can provide a unique fingerprint.In contrast,the latter has the characteristics of miniaturization and integration,which can realize accurate control of the detection samples and high-throughput detection through design.Both have the potential for point-of-care testing(POCT),and their combination(lab-on-a-chip SERS(LoC-SERS))shows good compatibility.In this paper,the basic situation of circulating proteins,circulating tumor cells,exosomes,circulating tumor DNA(ctDNA),and microRNA(miRNA)in the diagnosis of various cancers is reviewed,and the detection research of these biomarkers by the LoC-SERS platform in recent years is described in detail.At the same time,the challenges and future development of the platform are discussed at the end of the review.Summarizing the current technology is expected to provide a reference for scholars engaged in related work and interested in this field.
基金the National Science and Technology Innovation 2030(Nos.2021ZD0201000 and 2021ZD0201001)the National Natural Science Foundation of China(No.81971025)the Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(No.2019-I2M-5-014).
文摘Phosphorylation of tau at Ser(396,404)(p-tau^(396,404))is one of the earliest phosphorylation events,plasma p-tau^(396,404) level appears to be a potentially promising biomarker of Alzheimer’s disease(AD).The low abundance and easy degradation of p-tau in the plasma make the lateral flow assay(LFA)a suitable choice for point-of-care detection of plasma p-tau^(396,404) levels.Herein,based on our screening of a pair of p-tau^(396,404)-specific antibodies,we developed a colorimetric and surface-enhanced Raman scattering(SERS)dual-readout LFA for the rapid,highly sensitive,robust detection of plasma p-tau^(396,404) levels.This LFA realized a detection limit of 60 pg/mL by the naked eye or 3.8 pg/mL by SERS without cross-reacting with other tau species.More importantly,LFA rapidly and accurately differentiated AD patients from healthy controls,suggesting that it has the potential for clinical point-of-care application in AD diagnosis.This dual-readout LFA has the advantages of simple operation,rapid,ultra-sensitive detection,providing a new way for early AD diagnosis and intervention,especially in primary and community AD screening.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT).(NRF-2020R1A2C4002557)It was also supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education.(NRF-2021R1A6A3A13045573)Miri Choi at the KBSI(Chuncheon)is thanked for technical assistance with the FE-TEM analysis.
文摘Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of MoS_(2)-Ag nanocomposites via laser-assisted photoreduction was proposed.For the photoreduction process,we used AgNO_(3)solution as a metal source.Under laser irradiation,Ag ions were easily reduced on MoS_(2)by photo-generated electrons from MoS_(2).The optical properties of MoS_(2)-Ag nanocomposites were easily controlled by simple adjustment of the photoreduction time.To investigate the surface-enhanced Raman scattering(SERS)effect of the MoS_(2)-Ag nanocomposites,the SERS spectra of methylene blue(MB)on MoS_(2)-Ag nanocomposites were measured,and the nanocomposites were found to enhance the Raman scattering intensity of MB up to~106.Therefore,the laser-assisted photoreduction method has great potential for rapid synthesis and optical tuning of semiconductoremetal nanocomposites.
基金This work was supported by the National Natural Science Foundation of China(No.21707077)the Special Fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF20-06)the Fundamental Research Funds for the Central Universities(No.2020MS037).
文摘Surface-enhanced Raman scattering(SERS)has been used in atmospheric aerosol detection as it enables the high-resolution analysis of particulate matter.However,its use in the detection of historical samples without damaging the sampling membrane while achieving effective transfer and the high-sensitivity analysis of particulate matter from sample films remains challenging.In this study,a new type of SERS tape was developed,consisting of Au nanoparticles(NPs)on an adhesive double-sided Cu film(DCu).The enhanced electromagnetic field generated by the coupled resonance of the local surface plasmon resonances of AuNPs and DCu led to an enhanced SERS signal with an experimental enhancement factor of 10^(7).The AuNPs were semi-embedded and distributed on the substrate,and the viscous DCu layer was exposed,enabling particle transfer.The substrates exhibited good uniformity and favorable reproducibility with relative standard deviations of 13.53%and 9.74%respectively,and the substrates could be stored for 180 days with no signs of signal weakening.The application of the substrates was demonstrated by the extraction and detection of malachite green and ammonium salt particulate matter.The results demonstrated that SERS substrates based on AuNPs and DCu are highly promising in real–world environmental particle monitoring and detection.
