金纳米-Nylon柔性膜基底的制备及其SERS性能研究

表面增强拉曼光谱（SERS）是目前最灵敏的分析技术之一，广泛应用于生命科学、材料科学、环境科学及分析化学等领域。SERS基底的特性决定了该技术的实际应用范围，是推动该技术发展的关键，高活性SERS基底的制备已经逐渐成为SERS研究领域的热点。为了获得最佳的拉曼信号，对具有特殊特性的SERS活性基底的需求一直很大。柔性SERS基底因具有良好的柔韧性，3D支架结构和表面可控的孔径大小等独特优势，在检测化合物和细菌等方面有很好的应用价值。Nylon(尼龙)柔性膜表面具有分级及多孔交错排列3D结构的特点，将固相萃取装置与特殊材料Nylon柔性膜相结合，通过改变金纳米颗粒的附着量以及金纳米颗粒与膜结合次数，制备了高SERS活性的金纳米-Nylon（Au-Nylon）柔性膜基底。研究表明，金纳米颗粒能很好地附着在Nylon纤维上，纳米颗粒与Nylon柔性膜表面等离子共振耦合作用，形成金纳米颗粒与Nylon纤维的复合体，Au-Nylon柔性膜基底的等离子共振吸收峰发生蓝移。首次处理后的Nylon纤维与其所附着的金纳米颗粒形成新的活性截留层，有助于使再次处理时金颗粒更好地附着在柔性膜表面，产生SERS“热点”效应，提高其SERS性能。利用结晶紫（CV）作为SERS探针分子，对Au-Nylon柔性膜基底SERS性能进行分析，发现CV探针分子在Au-Nylon柔性膜基底上的SERS强度随金纳米颗粒的附着量以及金纳米颗粒与膜结合次数而变化。对于面积为1 cm2的Au-Nylon柔性膜基底，当单次过滤金溶胶1 mL，与膜结合2次，总结合量2 mL时，CV探针分子的SERS信号最强，SERS活性最强。采用Au-Nylon柔性膜基底对浓度为2.5×10-5，1×10-5，1×10-6，5×10-7及1×10-7 mol·L-1的CV溶液进行的SERS检测，发现Au-Nylon柔性膜基底对CV探针分子检测极限达1×10-6 mol·L-1，增强因子达到1.0×104。此外，Au-Nylon柔性膜基底均匀性较好，相对平均偏差为11.8%。Au-Nylon柔性膜基底在微生物检测中，仍具有良好SERS活性，对金黄色葡萄球菌的SERS增强效果优于金溶胶。由此可见，研究中制备的Au-Nylon柔性具有良好的均一性，并具有较好的SERS活性，该方法简单且易批量制备，无论在化合物检测还是微生物检测中都具有良好的实际应用价值。

Preparation and SERS Performance of Au-Nylon Flexible Membrane Substrate

Surface Enhanced Raman Spectroscopy (SERS) is one of the most sensitive analytical techniques currently available and has been widely used in life science, material science, environmental science and analytical chemistry. The performance of SERS base determines the application scope of SERS, are the key to promoting the development of SERS technology, the preparation of highly active SERS substrate has become a hot spot in the SERS research field. In order to obtain the best Raman signal, SERS active substrate with special characteristics is great demanded. Flexible SERS substrate has unique advantages such as good flexibility, 3D scaffold structure and controllable pore size on the surface, and it is a good application value in detecting compounds and bacteria. The surface of Nylon flexible film has the characteristics of the hierarchical and porous staggered structure. Au-Nylon flexible film substrate with high SERS activity was prepared by combining the solid phase extraction unit with the special material Nylon by changing the amount of gold sol and binding times of gold nanoparticles and film. The result showed that gold nanoparticles attach well to Nylon fibers, and the plasmon resonance absorption peak of the Au-Nylon flexible film substrate has blue moved, which was due to the intrinsic surface plasmon resonance coupling of gold and Nylon, forming Au nanoparticles and Nylon fiber complex. After the first treatment, Nylon fiber and its attached Au nanoparticles formed a new active retention layer, which contributes to making the gold particles better attached to the film’s surface during the second treatment, forming SERS “hot spot” effect and improving its SERS performance. The SERS performance of the Au-Nylon flexible film substrate was analyzed by using Crystal Violet (CV) as the SERS probe molecule. It was found that the SERS strength of the CV probe molecules on the Au-Nylon flexible film substrate varied as the number of filtration times and binding times of gold nanoparticles and film. For Au-Nylon flexible film substrate with an area of 1 cm2, When a single gold sol amount of 1 mL is combined with the film two times, and the total binding amount is 2 mL, the SERS signal of the CV probe molecules and the activity of SERS samples was the highest. The Au-Nylon flexible film substrate was used for SERS detection of the CV solution with a concentration of 2.5×10-5, 1×10-5, 1×10-6, 5×10-7 and 1×10-7 mol·L-1. Respectively, The Au-Nylon flexible film substrate enhancement factor reached 1.0×104, and the detection limit was 1.0×10-6 mol·L-1. In addition, The Au-Nylon flexible film substrate had good uniformity with a relative average deviation of 11.8%. The Au-Nylon film substrate still had good SERS performance in microbial detection, and the SERS enhanced effect on Staphylococcus aureus was better than that of gold sol. It could be seen that the Au-Nylon flexible film substrate has good homogeneity and good SERS activity. The method has the advantages of simple and easy batch preparation, and it has good practical application value in both compound detection and microbial detection.