Surface enhanced Raman scattering (SERS) has become widely used for identification, quantification and providing structural information about molecular structure in low concentrations as it allows signal Raman enhancement using metallic nanoparticles (NPs). Controlling interaction between analyte and NPs is a major point for the optimization of signal exaltation in SERS analysis. The objective of this study is the improvement and the control of SERS analysis by aggregation/self-assembly optimization of AuNPs using quaternized chitosan. The interest of this approach is to allow stable and reliable measurements with a simple and low cost approach compatible with a massive use in the field. In this work, we used design of experiments by Box-Behnken design to fix optimized conditions to increase signal sensibility of epinephrine water solutions. We also tested SERS signal stability in isotonic sodium chloride 0.9% and glucose 5% matrices.

Our results demonstrate that globally neutral AuNPs aggregates were stabilized at a nanometric size by the subsequent addition of polyelectrolyte chains and allows for significant Raman signal enhancement of epinephrine. We succeed to prepare the SERS active material and measure a stable signal of epinephrine at a concentration as down as 0.1 μg mL⁻¹ in less than 5 min. The signal remained stable and exploitable for at least 2 h. Our results reveal a strong correlation between intensity and logarithm of the concentration (concentration before dilution from 0.1 to 10 μg mL⁻¹) suggesting a possible quantification. Furthermore, the signal of epinephrine at 10 μg mL⁻¹ were also exploitable and stable in complex media as isotonic sodium chloride 0.9% and glucose 5%. This represents a particularly interesting application that would allow direct analysis of drugs complex media and open the way to analysis in biological samples.

表面增强拉曼散射 (SERS) 已广泛用于识别、量化和提供有关低浓度分子结构的结构信息，因为它允许使用金属纳米粒子 (NP) 增强信号拉曼。控制分析物和 NP 之间的相互作用是优化 SERS 分析中信号升高的重点。本研究的目的是通过使用季铵化壳聚糖的 AuNPs 的聚集/自组装优化来改进和控制 SERS 分析。这种方法的目的是通过与现场大量使用兼容的简单且低成本的方法实现稳定可靠的测量。在这项工作中，我们使用 Box-Behnken 设计的实验设计来修复优化条件，以提高肾上腺素水溶液的信号敏感性。

我们的结果表明，通过随后添加聚电解质链，全球中性 AuNPs 聚集体稳定在纳米尺寸，并允许显着增强肾上腺素的拉曼信号。我们成功地制备了 SERS 活性材料并在不到 5 分钟的时间内测量了浓度低至 0.1 μg mL ^{-1的肾上腺素的稳定信号。}信号保持稳定且可利用至少 2 小时。我们的结果揭示了浓度的强度和对数之间的强相关性（稀释前的浓度从 0.1 到 10 μg mL ^-1），表明可能进行量化。此外，10 μg mL ^{-1时的肾上腺素信号}在等渗氯化钠 0.9% 和葡萄糖 5% 等复杂介质中也可利用且稳定。这代表了一个特别有趣的应用，可以直接分析药物复合介质并打开生物样品分析的途径。