We review recent our results in the fundamental study of surface-enhanced Raman scattering （SERS） with emphasis on experiments that attempted to identify the enhancement and blinking mechanism using single Ag nanopa...We review recent our results in the fundamental study of surface-enhanced Raman scattering （SERS） with emphasis on experiments that attempted to identify the enhancement and blinking mechanism using single Ag nanoparticle dimers attached to dye molecules. These results are quantitatively discussed in the framework of electromagnetic mechanism. We also review recent our results in basic SERS applications for biological sensing regarding detections of cell surface molecules and distinction of disease marker molecules under single cell and single molecule level.展开更多
Studying the activity of individual nanocata- lysts, especially with high spatiotemporal resolution of single-molecule and single-turnover scale, is essential for the understanding of catalytic mechanism and the desig...Studying the activity of individual nanocata- lysts, especially with high spatiotemporal resolution of single-molecule and single-turnover scale, is essential for the understanding of catalytic mechanism and the designing of effective catalysts. Several approaches have been developed to monitor the catalytic reaction on single catalysts. In this review, we summarized the updated progresses of several new spectroscopic and microscopic approaches, including single-molecule fluorescence microscopy, surface-enhanced Raman spectroscopy, surface plasmon resonance microscopy and X-ray microscopy, for the study of single-molecule and single-particle catalysis.展开更多
COVID-19 has devastated numerous nations around the world and has overburdened numerous healthcare systems,which has also caused the loss of livelihoods due to prolonged shutdowns and further led to a cascading effect...COVID-19 has devastated numerous nations around the world and has overburdened numerous healthcare systems,which has also caused the loss of livelihoods due to prolonged shutdowns and further led to a cascading effect on the global economy.COVID-19 infections have an incubation period of 2–7 days,but 40 to 45%of cases are asymptomatic or show mild to moderate respiratory symptoms after the period due to subclinical lung abnormalities,making it more likely to spread the pandemic disease.To restrict the spread of the virus,on-site diagnosis methods that are quicker,more precise,and easily accessible are required.Rapid Antigen Detection Tests and Polymerase Chain Reaction tests are currently the primary methods used to determine the presence of COVID-19 viruses.These tests are typically time-consuming,not accurate,and,more importantly,not available to everyone.Hence,in this review and hypothesis,we proposed equipment that employs the properties of photonics to improve the detection of COVID-19 viruses by taking the advantage of typical binding of coronavirus with angiotensin-converting enzyme 2(ACE2)receptors.This hypothetical model would combine Surface-Enhanced Raman Scattering(SERS)and Fluorescence Resonance Energy Transfer(FRET)to provide great flexibility,high sensitivities,and enhanced accessibility.展开更多
Wheat leaves with natural microstructures as substrates were covered by the silver nanoislands by magnetron to prepare a low-cost, environment-friendly and mass production surface-enhanced fluorescence(SEF) substrate(...Wheat leaves with natural microstructures as substrates were covered by the silver nanoislands by magnetron to prepare a low-cost, environment-friendly and mass production surface-enhanced fluorescence(SEF) substrate(Ag-WL substrate). The best SEF substrate was selected by repeatly certifying the fluorescence intensity of 10^(-5)M Rhodamine B(RB) and 10^(-5)M Rhodamine 6G(R6G) aqueous solutions. The abundant semi-spherical protrusions and flake-like structures on the surface of the Ag-WL substrate produce high-density hot spots, which provides a new and simple idea for the preparation of biomimetic materials. The results of 3D finite-different time-domain(FDTD) simulation show that the nanoisland gap of semi-spherical protrusions and flake-like structures has produced rich hotspots. By adjusting the time of magnetron sputtering, the enhancement factor(EF) was as high as 839 times, relative standard deviation(RSD) reached as low as 10.7%, and the substrate was very stable and repeatable, which shows that Ag-WL substrate is trustworthy.Moreover, semi-spherical protrusions provide stronger surface-enhanced Raman scattering(SERS) effects compared to flake-like structure. What is more surprising is that the detection limit of the substrate for toxic substance crystal violet(CV) is as low as 10^(-10)M.展开更多
The preparation of surface-enhanced fluorescence(SEF) substrates is often influenced by experimental strategies and factors such as the morphology and size of the nanostructures. In this study, using the natural reed ...The preparation of surface-enhanced fluorescence(SEF) substrates is often influenced by experimental strategies and factors such as the morphology and size of the nanostructures. In this study, using the natural reed leaves(RLs) without any special pretreatment as the substrate, metal silver is modified by magnetron sputtering technology to prepare a stable and efficient SEF system. The abundant “hedgehog-like” protrusions on the RL substrate surface can generate high-density“hot spots”, thus enhancement factor(EF) is enhanced up to 3345 times. The stability and reproducibility are verified in many measurements. The contribution of the intervention of silver nanostructure to the radiation attenuation process of fluorescent molecules is analyzed with the aid of Jablonski diagrams. Three-dimensional(3D) finite difference time domain(FDTD) simulates the spatial electric field and “hot spots” distribution of the substrate. The “hedgehog-like” protrusion structure generates multiple “hot spots”, which produce an excellent local surface plasmon resonance(LSPR) effect and provide higher fluorescence signal. Finally, RL/Ag-35 substrate is used to detect crystal violet(CV), and the detection limit is as low as 10^(-13) M. This “hedgehog-like” SEF substrate provides a new strategy for the trace detection of CV, which has a good practical application value.展开更多
Sensitivity is crucially important for surface-enhanced Raman spectroscopy(SERS)application to detect trace-level polycyclic aromatic hydrocarbons(PAHs)in the seawater.In this study,a high sensitivity three-dimensiona...Sensitivity is crucially important for surface-enhanced Raman spectroscopy(SERS)application to detect trace-level polycyclic aromatic hydrocarbons(PAHs)in the seawater.In this study,a high sensitivity three-dimensional(3-D)SERS substrate composed with syringe filter,glycidyl methacrylate-ethylene dimethacrylate(GMA-EDMA)porous material and optimal parameters(57 nm,pH 13)gold nanoparticles(Au NPs)was developed for the detection of PAHs in water.The enhancement effect and repeatability of this 3-D substrate were also explored.The Raman intensity of pyrene using 3-D SERS substrate is about 8 times higher than that of substrate only using p H 13 gold colloid solution and about 12 times higher than that of substrate using natural Au NPs and GMA-EDMA porous material,which means both the pH 13 AuN Ps and the GMA-EDMA porous material are important factors for the sensitivity of this 3-D SERS substrate.Good repeatability of this optimal 3-D substrate was obtained.The relative standard deviation(RSD)is less than 8.66% on the same substrate and less than 3.69% on other different substrates.Four kinds of PAHs,i.e.,phenanthrene,pyrene,benzo(a)pyrene,benzo(k)fluoranthene and their mixture,were detected at the different concentrations.Their limits of detection(LODs)are 8.3×10^-10(phenanthrene),2.1×10^-10(pyrene),3.8×10^-10(benzo(a)pyrene)and 1.7×10^-10 mol L^-1(benzo(k)fluoranthene),respectively.In addition,these four PAHs were also detected by fluorescence spectroscopy to evaluate the sensitivity of SERS technology using this optimal 3-D SERS substrate.The results showed that the sensitivity of SERS based on the 3-D SERS substrate even using the portable Raman system was closed to that of fluorescence spectroscopy.Therefore,the SERS technology using this optimal 3-D substrate is expected to be an in-situ method for the detection of environmental PAHs.展开更多
文摘We review recent our results in the fundamental study of surface-enhanced Raman scattering （SERS） with emphasis on experiments that attempted to identify the enhancement and blinking mechanism using single Ag nanoparticle dimers attached to dye molecules. These results are quantitatively discussed in the framework of electromagnetic mechanism. We also review recent our results in basic SERS applications for biological sensing regarding detections of cell surface molecules and distinction of disease marker molecules under single cell and single molecule level.
文摘Studying the activity of individual nanocata- lysts, especially with high spatiotemporal resolution of single-molecule and single-turnover scale, is essential for the understanding of catalytic mechanism and the designing of effective catalysts. Several approaches have been developed to monitor the catalytic reaction on single catalysts. In this review, we summarized the updated progresses of several new spectroscopic and microscopic approaches, including single-molecule fluorescence microscopy, surface-enhanced Raman spectroscopy, surface plasmon resonance microscopy and X-ray microscopy, for the study of single-molecule and single-particle catalysis.
文摘COVID-19 has devastated numerous nations around the world and has overburdened numerous healthcare systems,which has also caused the loss of livelihoods due to prolonged shutdowns and further led to a cascading effect on the global economy.COVID-19 infections have an incubation period of 2–7 days,but 40 to 45%of cases are asymptomatic or show mild to moderate respiratory symptoms after the period due to subclinical lung abnormalities,making it more likely to spread the pandemic disease.To restrict the spread of the virus,on-site diagnosis methods that are quicker,more precise,and easily accessible are required.Rapid Antigen Detection Tests and Polymerase Chain Reaction tests are currently the primary methods used to determine the presence of COVID-19 viruses.These tests are typically time-consuming,not accurate,and,more importantly,not available to everyone.Hence,in this review and hypothesis,we proposed equipment that employs the properties of photonics to improve the detection of COVID-19 viruses by taking the advantage of typical binding of coronavirus with angiotensin-converting enzyme 2(ACE2)receptors.This hypothetical model would combine Surface-Enhanced Raman Scattering(SERS)and Fluorescence Resonance Energy Transfer(FRET)to provide great flexibility,high sensitivities,and enhanced accessibility.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 21872119 and 22072127)Science and Technology Project of Hebei Education Department, China (Grant No. ZD2019069)。
文摘Wheat leaves with natural microstructures as substrates were covered by the silver nanoislands by magnetron to prepare a low-cost, environment-friendly and mass production surface-enhanced fluorescence(SEF) substrate(Ag-WL substrate). The best SEF substrate was selected by repeatly certifying the fluorescence intensity of 10^(-5)M Rhodamine B(RB) and 10^(-5)M Rhodamine 6G(R6G) aqueous solutions. The abundant semi-spherical protrusions and flake-like structures on the surface of the Ag-WL substrate produce high-density hot spots, which provides a new and simple idea for the preparation of biomimetic materials. The results of 3D finite-different time-domain(FDTD) simulation show that the nanoisland gap of semi-spherical protrusions and flake-like structures has produced rich hotspots. By adjusting the time of magnetron sputtering, the enhancement factor(EF) was as high as 839 times, relative standard deviation(RSD) reached as low as 10.7%, and the substrate was very stable and repeatable, which shows that Ag-WL substrate is trustworthy.Moreover, semi-spherical protrusions provide stronger surface-enhanced Raman scattering(SERS) effects compared to flake-like structure. What is more surprising is that the detection limit of the substrate for toxic substance crystal violet(CV) is as low as 10^(-10)M.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11674275, 21872119, 22072127, and 12104392)the Science and Technology Project of Hebei Education Department, China (Grant No. ZD2019069 and QN2021142))。
文摘The preparation of surface-enhanced fluorescence(SEF) substrates is often influenced by experimental strategies and factors such as the morphology and size of the nanostructures. In this study, using the natural reed leaves(RLs) without any special pretreatment as the substrate, metal silver is modified by magnetron sputtering technology to prepare a stable and efficient SEF system. The abundant “hedgehog-like” protrusions on the RL substrate surface can generate high-density“hot spots”, thus enhancement factor(EF) is enhanced up to 3345 times. The stability and reproducibility are verified in many measurements. The contribution of the intervention of silver nanostructure to the radiation attenuation process of fluorescent molecules is analyzed with the aid of Jablonski diagrams. Three-dimensional(3D) finite difference time domain(FDTD) simulates the spatial electric field and “hot spots” distribution of the substrate. The “hedgehog-like” protrusion structure generates multiple “hot spots”, which produce an excellent local surface plasmon resonance(LSPR) effect and provide higher fluorescence signal. Finally, RL/Ag-35 substrate is used to detect crystal violet(CV), and the detection limit is as low as 10^(-13) M. This “hedgehog-like” SEF substrate provides a new strategy for the trace detection of CV, which has a good practical application value.
基金supported by the National Natural Science Foundation of China (No. 41476081)the Major Research and Development Project in Shandong Province (Nos. 2016GSF115020, 2019GHY112027)the Shandong Provincial Natural Science Foundation (No. ZR2015DM007)
文摘Sensitivity is crucially important for surface-enhanced Raman spectroscopy(SERS)application to detect trace-level polycyclic aromatic hydrocarbons(PAHs)in the seawater.In this study,a high sensitivity three-dimensional(3-D)SERS substrate composed with syringe filter,glycidyl methacrylate-ethylene dimethacrylate(GMA-EDMA)porous material and optimal parameters(57 nm,pH 13)gold nanoparticles(Au NPs)was developed for the detection of PAHs in water.The enhancement effect and repeatability of this 3-D substrate were also explored.The Raman intensity of pyrene using 3-D SERS substrate is about 8 times higher than that of substrate only using p H 13 gold colloid solution and about 12 times higher than that of substrate using natural Au NPs and GMA-EDMA porous material,which means both the pH 13 AuN Ps and the GMA-EDMA porous material are important factors for the sensitivity of this 3-D SERS substrate.Good repeatability of this optimal 3-D substrate was obtained.The relative standard deviation(RSD)is less than 8.66% on the same substrate and less than 3.69% on other different substrates.Four kinds of PAHs,i.e.,phenanthrene,pyrene,benzo(a)pyrene,benzo(k)fluoranthene and their mixture,were detected at the different concentrations.Their limits of detection(LODs)are 8.3×10^-10(phenanthrene),2.1×10^-10(pyrene),3.8×10^-10(benzo(a)pyrene)and 1.7×10^-10 mol L^-1(benzo(k)fluoranthene),respectively.In addition,these four PAHs were also detected by fluorescence spectroscopy to evaluate the sensitivity of SERS technology using this optimal 3-D SERS substrate.The results showed that the sensitivity of SERS based on the 3-D SERS substrate even using the portable Raman system was closed to that of fluorescence spectroscopy.Therefore,the SERS technology using this optimal 3-D substrate is expected to be an in-situ method for the detection of environmental PAHs.
