synthesis of silver nanoparticles and preparation of flexible sers detection substrate

用于 R6G 和 Thiram 的 SERS 检测的柔性衬底的制备

Surface-Enhanced Raman Scattering (SERS), as a type of Raman scattering, offers the advantages of high sensitivity and gentle detection conditions, and can even achieve single molecule detection1,2,3,4. Metal nanostructures, such as gold and silver, are typically used as SERS substrates to enable substance detection5,6. Electromagnetic coupling enhancement on nanostructured surfaces plays a significant role in SERS applications. Metallic nanostructures with varying sizes, shapes, interparticle distances, and compositions can aggregate to create numerous &#34;hotspots&#34; generating intense electromagnetic fields due to localized surface plasmon resonances7,8. Many studies have developed metal nanoparticles with different morphologies as SERS substrates, demonstrating their effectiveness in achieving SERS enhancement9,10.
Flexible SERS substrates find wide applications, with nanostructures capable of producing SERS effects deposited on flexible substrates to facilitate direct detection on curved surfaces. Flexible SERS substrates are employed for detecting and collecting analytes on irregular, non-planar, or curved surfaces. Common flexible SERS substrates include fibers, polymer films, and graphene oxide films11,12,13,14. Among them, polydimethylsiloxane (PDMS) is one of the most widely used polymer materials and offers advantages such as high transparency, high tensile strength, chemical stability, non-toxicity, and adhesion15,16,17. PDMS has a low Raman cross-section, making its impact on the Raman signal negligible18. Since the PDMS prepolymer is in liquid form, it can be cured by heat or light, providing a high degree of controllability and convenience. PDMS-based SERS substrates are relatively common flexible SERS substrates, having been used in previous studies to embed various metal nanoparticles for detecting different biochemical substances with exemplary performance19,20.
In the preparation of SERS substrates, the fabrication of nanogap structures is crucial. Physical deposition technology offers advantages like high scalability, uniformity, and reproducibility but typically requires good vacuum conditions and specialized equipment, limiting its practical applications21. Additionally, fabricating nanostructures at the few-nanometer scale remains challenging with conventional deposition techniques22. Consequently, nanoparticles synthesized through chemical methods can be adsorbed onto flexible transparent films through various interactions, facilitating the self-assembly of metallic structures at the nanoscale. To ensure successful adsorption, interactions can be adjusted by physically or chemically modifying the film surface to alter its surface hydrophilicity23. Silver nanoparticles, compared to gold nanoparticles, exhibit better SERS performance, but their instability, particularly their susceptibility to oxidation in air, results in a rapid decrease in the SERS Enhancement Factor (EF), affecting substrate performance24. Hence, it is essential to develop a stable particle method.
The presence of pesticide residues has garnered significant attention, creating a pressing need for robust methods capable of rapidly detecting and identifying various classes of hazardous chemicals in food in the field25,26. Flexible SERS substrates offer unique advantages in practical applications, particularly in the realm of food safety. This article introduces a method for preparing a flexible SERS substrate by bonding synthesized glucose-coated silver nanoparticles (AgNPs) onto a PDMS substrate (Figure 1). The presence of glucose protects the AgNPs, mitigating silver oxidation in the air. The substrate demonstrates excellent detection performance, capable of detecting Rhodamine 6G (R6G) as low as 10-10 M and pesticide Thiram as low as 10-8 M, with good uniformity. Moreover, the flexible substrate can be employed for detection through bonding and sampling, with numerous potential application scenarios.

作者聚焦：使用合成的 AgNP 开发与应用 SERS 柔性底物 

基于聚二甲基硅氧烷（PDMS）的柔性表面增强拉曼散射（SERS）衬底的制备及其超灵敏检测

This protocol describes preparing SERS flexible substrates, applying them to actual detection scenarios. The SERS flexible substrate offered by this protocol is environmental friendly and achieves good detection performance. The silver nanoparticles can be synthesized easily by simple vessels, and do not require complicated experimental conditions and environment.In our laboratory, we plan to focus on researching the silver nanoparticles synthesized through the vessel used in this study. We'll explore methods to enhance their SERS detection capabilities, and leverage their unique properties and characteristics to design better performing SERS detection substrates.

Watch this Scientific Journal Video about Synthesis of Silver Nanoparticles and Preparation of Flexible SERS Detection Substrate at JoVE.com

Synthesis of Silver Nanoparticles and Preparation of Flexible SERS Detection Substrate  

纳米银颗粒的合成及柔性SERS检测底物的制备

要制备硝酸银溶液，请在称重天平上测量 0.0017 克 AR 级硝酸银。将称量的粉末加入 10 毫升去离子水中并搅拌混合物。用注射器抽取一毫升AR级氨水，在搅拌的同时加入硝酸银溶液中，直到溶液变得清澈。要制备 0.2 摩尔葡萄糖溶液，称取 0.36 克葡萄糖粉并将其加入 10 毫升去离子水中。彻底搅拌混合物。接下来，使用移液枪，每隔 30 分钟将 30 微升银氨络合物加入葡萄糖溶液中。合成黄色银纳米颗粒。要合成PDMS底物，取5克PDMS A溶液，并以1：10的比例加入B溶液。彻底搅拌混合物。将混合的PDMS转移到方形培养皿中，并在80摄氏度的烤箱中烘烤两小时。腌制后，用手术刀沿着盘子的深色网格切割PDMS，形成小立方体。接下来，将手持式等离子处理器在PDMS部件上来回移动，以进行表面等离子处理。对于APTES改性，将表面改性的PDMS片段浸入10%APTES溶液中10小时。最后，将PDMS底物浸入银纳米颗粒溶液中10小时。ESEM图像显示直径在20至50纳米之间的合成纳米颗粒具有均匀性。表面增强拉曼散射信号对制备的PDMS衬底表现出优异的检测能力，在R6G的负10摩尔范围内达到10的极限，增强效果显著。底物还显示 Thiram 检测具有明显的特征峰，高达 10 至负第八磨牙。苹果表面的糊状和去皮方法显示，Thiram的检测结果高达10至负第七磨牙，表明基质在识别水果表面农药残留方面的有效性。

synthesis-silver-nanoparticles-preparation-flexible-sers-detection

Research

JoVE Journal

Engineering

Synthesis of Silver Nanoparticles and Preparation of Flexible SERS Detection Substrate

392 次观看.  Peking University. 要制备硝酸银溶液，请在称重天平上测量 0.0017 克 AR 级硝酸银。将称量的粉末加入 10 毫升去离子水中并搅拌混合物。用注射器抽取一毫升AR级氨水，在搅拌的同时加入硝酸银溶液中，直到溶液变得清澈。要制备 0.2 摩尔葡萄糖溶液，称取 0.36 克葡萄糖粉并将其加入 10 毫升去离子水中。彻底搅拌混合物。接下来，使用移液枪，每隔 30 分钟将 30 微升银氨络合物加入葡萄糖?...

视频: Synthesis of Silver Nanoparticles and Preparation of Flexible SERS Detection Substrate  

Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) were synthesized through a complexation reaction involving silver nitrate (AgNO3) and ammonia, followed by reduction using glucose. The resulting AgNPs exhibited a uniform size distribution ranging from 20 nm to 50 nm. Subsequently, 3-aminopropyl triethoxysilane (APTES) was employed to modify a PDMS substrate that had been surface-treated with oxygen plasma. This process facilitated the self-assembly of AgNPs onto the substrate. A systematic evaluation of the impact of various experimental conditions on substrate performance led to the development of a SERS substrate with excellent performance and an Enhanced Factor (EF). Utilizing this substrate, impressive detection limits of 10-10 M for R6G (Rhodamine 6G) and 10-8 M for Thiram were achieved. The substrate was successfully employed for detecting pesticide residues on apples, yielding highly satisfactory results. The flexible SERS substrate demonstrates great potential for real-world applications, including detection in complex scenarios.

This protocol describes a fabrication method for a flexible substrate for surface-enhanced Raman scattering. This method has been used in the successful detection of low concentrations of R6G and Thiram.

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) ...

科研

工程学

To prepare silver nitrate solution, measure 0.0017 grams of AR grade silver nitrate on a weighing balance. Add the weighed powder to 10 milliliters of deionized water and stir the mixture. Draw one milliliter of AR grade ammonia water using a syringe and add it to the silver nitrate solution while stirring, until the solution becomes clear.To prepare 0.2 molar glucose solution, weigh 0.36 grams of glucose powder and add it to 10 milliliters of deionized water. Stir the mixture thoroughly. Next, using a pipette gun, add 30 microliters of the silver ammonia complex into the glucose solution at 30 minute intervals.To synthesize yellow colored silver nanoparticles. To synthesize the PDMS substrate, take five grams of PDMS A solution and add B solution into it, at a ratio of one to 10. Stir the mixture thoroughly.Transfer the mixed PDMS into a square Petri dish and bake it in an 80 degree Celsius oven for two hours. Once cured, use a scalpel to cut the PDMS along the dark grid of the dish, creating small cubes. Next, move the handheld plasma processor back and forth over the PDMS piece for surface plasma treatment.For APTES modification, immerse the surface modified PDMS pieces into 10%APTES solution for 10 hours. Finally, immerse the PDMS substrate into the silver nanoparticle solution for 10 hours. ESEM images showed uniformity in synthesized nanoparticles with diameters between 20 and 50 nanometers.The Surface-Enhanced Raman Scattering signals for fabricated PDMS substrates displayed excellent detection capability, reaching a limit of 10 to the negative 10th molar for R6G with notable enhancement effect. The substrate also showed Thiram detection with clear characteristic peaks, up to 10 to the minus eighth molar. The paste and peel method on the apple surface show the detection of Thiram up to 10 to the minus seventh molar, indicating the effectiveness of the substrate for identifying pesticide residues on fruit surfaces.