- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Broadband Defects Emission and Enhanced Ligand Raman Scattering in 0D Cs <sub/>3</sub> Bi <sub/>2</sub> I <sub/>9</sub> Colloidal Nanocrystals
摘要： Excitonic 0D and 2D lead-halide perovskites have been recently developed and investigated as new materials for light generation. Here broadband (>1 eV) emission from newly synthesized 0D lead-free colloidal Cs3Bi2I9 nanocrystals (NCs) is reported. The nature of their emissive states as well as the relative dynamics which are currently hotly debated are investigated. In particular, it is found that the broadband emission is made by the coexistence of emissive excitons and sub-bandgap emissive trap-states. Remarkably, evidence of enhanced Raman scattering from the ligands is observed when attached to the NCs surface, an effect that is preliminarily attributed to strong exciton-ligands electronic coupling in these systems.
关键词： trap-states emission,enhanced Raman scattering,broadband emission,lead-free perovskites,0D nanocrystals
更新于2025-09-10 09:29:36
-
Copper-surrogated galvanic displacement of silver dendrite imprinted on flexible and transparent silk fibroin membrane as a SERS-active substrate and sub-dividable catalyst
摘要： By employing copper grid as a surrogate agent, we present a facial, reagent-free and cost-e?ective approach to imprint the exquisite silver dendroid nanostructures on ?exible silk ?broin membrane, which double roles as both optical enhancers and catalytic-active sites over many chemical reactions. Unlike the conventional rigid substrates, this hybrid Ag/protein composite exhibits many previous-inaccessible properties of ?exibility, transparency, biocompatibility, molecular permeability and optical manipulation. The galvanic displacement was facilitated by a high pressure uv-lamp illumination (365 nm), shortening the dendroid growth time to be within a few minutes. The resulting substrate was characterized by microscopic image, revealing a decent 3D Ag dendrite architecture and interpenetrated crystal network, which arguably enlarged the entire surface area and keenly regulated the optical/electric property of ?brillated protein ?lm. The underlying principle of copper-initiated silver reduction and growth of crystal structure was discoursed and veri?ed with in-situ spectroscopic interrogation. Moreover, our comprehensive study supports that sub-dividable substrate enables to perform catalytic reaction under a wide range of conditions. This exploration renders a thrust to expand biopolymeric membrane into a wide breadth of applications of bendable devices through chemical modi?cations, exhaustively and economically.
关键词： Galvanic replacement,Surface-enhanced Raman scattering,Sub-dividable catalyst,Silk membrane,Plasmon-driven photo-reduction
更新于2025-09-10 09:29:36
-
A high-resolution study of in situ surface-enhanced Raman scattering nanotag behavior in biological systems
摘要： The colloidal stability of surface-enhanced Raman scattering (SERS) nanotags (Raman reporter-conjugated plasmonic nanoparticles) significantly affects the accuracy and reproducibility of SERS measurements, particularly in biological systems. Limited understanding of SERS nanotag stability may partly hamper the translation of SERS nanotags from the laboratory to their use in the clinic. In this contribution, we utilized differential centrifugal sedimentation (DCS), a reliable and straightforward technique to comprehensively analyze the colloidal stability of SERS nanotags in biological systems. Compared with other particle characterization techniques, DCS has been shown to have a unique advantage for high-resolution and high-throughput polydisperse particle characterization. DCS data revealed that the universal aggregation prevention practice of coating SERS nanotags with silica or bovine serum albumin layers did not sufficiently stabilize them in common measurement environments (e.g., 1× PBS). Combined DCS and SERS measurements established a strong correlation between the degrees of nanotag aggregation and signal intensities, further reinforcing the necessity of characterizing SERS nanotag stability for every condition in which they are used. We also found that increasing the protein thickness by the inclusion of extra protein components in the detection environments and antibody functionalization can improve the stability of SERS nanotags. We believe that this study can provide guidelines on appropriate measurement techniques and particle design considerations to assess and improve SERS nanotag stability in complex biological systems.
关键词： surface-enhanced Raman scattering (SERS),plasmonic nanoparticles,differential centrifugal sedimentation (DCS),SERS nanotags,colloidal stability
更新于2025-09-10 09:29:36
-
Fluorescence-SERS dual-signal probes for pH sensing in live cells
摘要： The activity of many cells is closely related to the pH of their internal environment, and the increase of intracellular pH value is a common feature of many drug-resistant tumors. The intracellular pH needs to be determined as the research basis when studying the intracellular transport protein and ion concentration changes. Nanomaterials are now widely used as the effective imaging and drug delivery vehicles, but it remains to be studied as a sensor for intracellular environment. Based on this, we have constructed a nanoprobe with fluorescence and surface-enhanced Raman scattering (SERS) dual-signal for sensing intracellular pH. The principle of this strategy is to construct fluorescence-SERS dual-signal nanoprobes by modifying pH-responsive fluorescent probes and SERS reporter molecules on the surface of gold nanorods (AuNRs) with the core-shell structure. The fluorescence-SERS dual response of the nanoprobe to pH can be achieved by investigating the fluorescence and SERS spectra of nanoprobes at different pH. Moreover, by incubating the nanoprobes into different cells, different double-signal response results can be obtained, thereby achieving intracellular pH sensing. The nanoprobe has dual responsiveness to fluorescence and SERS, which makes up for many of the deficiencies of single-signal probes, and realizes high sensitivity, accuracy and stability of intracellular pH detection. It is expected to be widely applied in the fields of medicine, chemistry and biology.
关键词： Dual-signal,Intracellular pH,Fluorescence,Surface-enhanced Raman scattering,Nanoprobe
更新于2025-09-10 09:29:36
-
Quantitative Determination of Urine Glucose: Combination of Laminar Flow in Microfluidic Chip with SERS Probe Technique
摘要： A surface-enhanced Raman scattering(SERS) sensing approach for urine glucose was developed based on the laminar flow technology in a cross-type microfluidic chip with SERS probes, 4-mercaptophenylboronic acid (MPBA) functionalized Ag nanoparticles. MPBA as the glucose receptor can identify and bind up with glucose at a molar ratio of 2:1, which can cause the aggregation of SERS probes at a certain position of the chip channel and further enhance the SERS signal of MPBA significantly. Thus, the quantitative SERS detection of glucose was achieved indirectly. No sample pretreatment and separation were needed in this method since the SERS detection was achieved in the gradient diffusion and molecular recognition processes between urine glucose and SERS probe in the laminar flow, which simplified the sample treatment procedures, saved detection time and made it feasible for clinic applications. This method shows a good linear relationship within human body’s normal physiological range and has high sensitivity and selectivity. The lowest detection concentration can reach 1.0 mg/dL.
关键词： Urine glucose,4-Mercaptophenylboronic acid,Microfluidic chip,Surface-enhanced Raman scattering(SERS)
更新于2025-09-10 09:29:36
-
Two dimensional sinusoidal Ag nanograting exhibits polarization-independent surface-enhanced Raman spectroscopy and its surface plasmon polariton and localized surface plasmon coupling with Au nanospheres colloids
摘要： A reproducible surface‐enhanced Raman scattering (SERS) substrate based on two dimensional (2D) sinusoidal Ag nanograting is presented. This SERS substrate with large area can be easily fabricated by maskless laser interference photolithography. The potential SERS polarization‐independent performance of 2D sinusoidal Ag nanograting is deduced by finite difference time domain and demonstrated by SERS detection experiments. A double‐enhanced Raman scattering (DERS) substrate by coupling 2D sinusoidal Ag nanograting with Au nanospheres colloids is created. With the optimal DERS substrate, SERS enhancement factor can be 10 orders of magnitude as possible. The DERS substrate was fabricated and an extra SERS effect was proved by experiments. This DERS substrate will be fabricated in a microfluidics‐based sensor in the next work and used for in situ, real‐time, continuous monitoring of trace water soluble gas‐phase or airborne agents, such as trace explosives in air.
关键词： surface plasmon polaritons,surface enhanced Raman scattering,localized surface plasmons,two dimensional sinusoidal nanograting,polarization‐independent
更新于2025-09-10 09:29:36
-
Morphology Effect on SERS Activity of Embedded Silver Nanostructures
摘要： Embedded silver nanostructures with different shapes and sizes are grown in Si substrates by chemical vapor deposition (CVD) method. Systematic study of their surface-enhanced Raman properties is performed. Influence of shape, size, and coverage of the nanoparticles on the average enhancement factors is calculated with the help of standard analyte molecules viz. crystal violet and Rhodamine 6G to optimize the substrates for future sensing applications.
关键词： embedded nanostructures,chemical vapor deposition,silver nanostructures,surface-enhanced Raman scattering
更新于2025-09-09 09:28:46
-
A surface-enhanced Raman scattering-based lateral flow immunosensor for colistin in raw milk
摘要： A surface-enhanced Raman scattering (SERS)-based lateral flow immunosensor was created to identify colistin in milk. The Raman reporter 5,5-dithiobis-2-nitrobenzoic acid (DTNB) was used to label gold nanoparticles, and then anti-colistin monoclonal antibody (mAb) was attached. The size of the gold nanoparticles in the SERS nanoprobe was optimized, and the amount of DTNB and mAb, the change in hydrodynamic size, zeta potential, and the surface plasmon resonance band were also monitored in the preparation process. The SERS nanoprobe was then applied to a lateral flow strip followed by Raman signal readout for the quantitative determination of colistin with high sensitivity. The limits of detection of this assay were 0.10 ng/mL for colistin in milk, which was far below the previously reported value that was obtained with the ELISA method and the maximum residue limit set by the European Union. The spiking experiment showed high accuracy for this SERS-based immunosensing assay, with a recovery of 88.1% to 112.7% and satisfactory assay precision with a standard deviation below 15%. Furthermore, this assay also has the advantage of rapidity, with an assay time less than 20 min. Therefore, these results demonstrate that this SERS-based lateral flow immunosensor is promising for use in the rapid monitoring of colistin in milk.
关键词： Surface enhanced Raman scattering,Immunoassay,Sensor,Milk,Colistin
更新于2025-09-09 09:28:46
-
Three-Dimensional Hierarchical Reticular Nanostructure of Fulfora candelaria Wing Decorated by Ag Nanoislands as Practical SERS-Active Substrates
摘要： Although surface-enhanced Raman scattering (SERS) technology has been widely explored nowadays in various fields, the fabrication of practical SERS-active substrates with prominent recognition ability for various analyte molecules is still defective. Natural Fulfora candelaria wing (FCW) with three-dimensional (3D) hierarchical reticular nanostructure was selected as a new bioscaffold for rough silver (Ag) nanoislands to be assembled on to prepare a practical SERS substrate (Ag/FCW substrate). By adjusting the sputtering time of metal Ag, the morphology of the substrates could be easily tuned to control the formation and distribution of “hot spots”. Three-dimensional finite-difference time-domain (3D-FDTD) simulation indicated that the excellent SERS performance under optimal morphology was ascribed to the local enhanced electric field in rough Ag surface and effective “hot spot” areas. The SERS measurement results show that the optimal Ag/FCW substrates had high SERS performance in terms of Raman signal sensitivity, reproducibility, uniformity and recognition ability for various analyte molecules. Coupled with flexibility of the biological substrates and the cost effectiveness, the sensitive SERS detection of varied analytes based on Ag/FCW substrates offered great potential for practical applications.
关键词： surface-enhanced Raman scattering,Fulfora candelaria wing,recognition ability,three-dimensional finite-difference time-domain simulation,practicability
更新于2025-09-09 09:28:46
-
A simple strategy to improve the sensitivity of probe molecules on SERS substrates
摘要： In this work, we report a simple strategy to improve the detection sensitivity as well as the spectral quality of probe molecules on surface-enhanced Raman scattering (SERS) substrates. On normal SERS substrates, due to the decreased absorption capacity and changes in the molecule orientations, SERS signals disappear when the analyte molecule concentrations reach a limit value. To solve this problem, the molecular template reagent (MTR) technique, a simple strategy based on SERS surface selection rules, is considered. By choosing the best MTR according to different samples, the effect of adjusting the molecular orientations of samples can be studied. In this process, 1-butanethiol, 1-hexanethiol, 1-octanethiol, 1-decanethiol, and 1-dodecanethiol, which are MTRs, are used to adjust the orientations of probe molecules under optimized conditions. The use of the MTR technique indicated that the limit of detection (LOD) of the probe molecules of p-aminobenzenethiol and 4-mercaptobenzoic acid on noble metal substrates showed an increase of one order of magnitude over the LOD of the pure probing molecule systems. Hence, the proposed method introduces a way to detect the molecules with an improved sensitivity at extremely low concentrations. The study corresponds to a proof-of-concept study of MTR-assisted SERS for SERS-based applications in ultrasensitive analyses.
关键词： Surface-enhanced Raman scattering (SERS),Molecular template reagent (MTR),Ultrasensitive analyses,SERS substrates
更新于2025-09-09 09:28:46