Samodelova Mariia V, Kapitanova Olesya O, Evdokimov Pavel V, Eremina Olga E, Goodilin Eugene A, Veselova Irina A
Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991, Russia.
Center for photonics and 2D materials, Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region, 141701, Russia.
Nanotechnology. 2022 May 25;33(33). doi: 10.1088/1361-6528/ac6c98.
A scalable procedure of SERS substrates design was developed using a novel plasmonic structure based on a freestanding chitosan film, silver nanoparticles, and graphene oxide. Chitosan provides a uniform distribution of silver nanoparticles from a colloidal suspension and, therefore, a reproducible Raman signal from local areas of measurements of several tens of microns. The addition of graphene oxide (GO) to the colloidal solution of silver nanoparticles suppresses the tortuous background fluorescence signal from the analyte and leads to an increase in the signal-to-fluorescence background intensity ratio by up to 6 times as compared to structures without GO. The manufactured plasmonic polymer nanocomposite provides a detection limit of down to 100 pM for R6G using a laser wavelength of 532 nm through a portable ×10 objective. The high colloidal stability of GO in water and the use of an aqueous colloid of silver nanoparticles simplify the procedure for creating a substrate by applying the GO-silver composite on the surface of a chitosan film without a need to form a GO film. Therefore, our approach paves a promising avenue to provide more sensitive detection even for the fluorescent analytes with short-wavelength lasers (532, 633 nm) instead of IR (785, 1024 nm) and foster the practical application of the developed plasmonic composites on portable Raman spectrometers.
利用基于独立壳聚糖膜、银纳米颗粒和氧化石墨烯的新型等离子体结构，开发了一种可扩展的表面增强拉曼散射（SERS）基底设计方法。壳聚糖能使银纳米颗粒从胶体悬浮液中均匀分布，从而在几十微米的局部测量区域产生可重复的拉曼信号。在银纳米颗粒胶体溶液中添加氧化石墨烯（GO）可抑制分析物产生的曲折背景荧光信号，并使信号与荧光背景强度比相较于不含GO的结构提高多达6倍。通过便携式×10物镜，使用532 nm激光波长，制造的等离子体聚合物纳米复合材料对罗丹明6G（R6G）的检测限低至100 pM。GO在水中的高胶体稳定性以及银纳米颗粒水胶体的使用，简化了通过将GO - 银复合材料涂覆在壳聚糖膜表面来制备基底的过程，无需形成GO膜。因此，我们的方法为使用短波长激光器（532、633 nm）而非红外激光器（785、1024 nm）对荧光分析物进行更灵敏检测铺平了一条有前景的道路，并促进了所开发的等离子体复合材料在便携式拉曼光谱仪上的实际应用。
