Analytical Chemistry Department, Faculty of Pharmacy, Iuliu Hațieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania.
MedFuture Research Center for Advanced Medicine, Iuliu Hațieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania.
Sensors (Basel). 2021 Dec 29;22(1):236. doi: 10.3390/s22010236.
Extensive effort and research are currently channeled towards the implementation of SERS (Surface Enhanced Raman Spectroscopy) as a standard analytical tool as it has undisputedly demonstrated a great potential for trace detection of various analytes. Novel and improved substrates are continuously reported in this regard. It is generally believed that plasmonic nanostructures with plasmon resonances close to the excitation wavelength (on-resonance) generate stronger SERS enhancements, but this finding is still under debate. In the current paper, we compared off-resonance gold nanobones (GNBs) with on-resonance GNBs and gold nanorods (GNRs) in both colloidal dispersion and as close-packed films self-assembled at liquid-liquid interface. Rhodamine 6G (R6G) was used as a Raman reporter in order to evaluate SERS performances. A 17-, 18-, and 55-fold increase in the Raman signal was observed for nanostructures (off-resonance GNBs, on-resonance GNBs, and on-resonance GNRs, respectively) assembled at liquid-liquid interface compared to the same nanostructures in colloidal dispersion. SERS performances of off-resonance GNBs were superior to on-resonance nanostructures in both cases. Furthermore, when off-resonance GNBs were assembled at the liquid interface, a relative standard deviation of 4.56% of the recorded signal intensity and a limit of detection (LOD) of 5 × 10 M could be obtained for R6G, rendering this substrate suitable for analytical applications.
目前，人们正在大力研究和努力将 SERS（表面增强拉曼光谱）作为一种标准分析工具来实施，因为它已经无可争议地证明了在痕量检测各种分析物方面具有巨大的潜力。在这方面，不断有新的和改进的基底被报道。一般认为，等离子体纳米结构的等离子体共振与激发波长（共振）接近时，会产生更强的 SERS 增强，但这一发现仍存在争议。在当前的论文中，我们比较了离共振金纳米骨（GNBs）与在共振金纳米骨（GNBs）和金纳米棒（GNRs）在胶体分散体中和作为紧密堆积的薄膜自组装在液-液界面。罗丹明 6G（R6G）被用作拉曼报告者，以评估 SERS 性能。在液-液界面组装的纳米结构（离共振 GNBs、共振 GNBs 和共振 GNRs）与胶体分散体中的相同纳米结构相比，拉曼信号分别增加了 17、18 和 55 倍。在这两种情况下，离共振 GNBs 的 SERS 性能都优于共振纳米结构。此外，当离共振 GNBs 在液体界面组装时，对于 R6G，可以获得 4.56%的记录信号强度的相对标准偏差和 5×10 M 的检测限（LOD），这使得该基底适合分析应用。
