Saxitoxin (STX) as one of the most harmful and typical paralytic shellfish toxins, is posing a serious threat to environmental and human health, thus it is essential to develop a sensitive and reliable analytical method for STX detection. Herein, we proposed a strategy for rapid and sensitive detection of STX with surface-enhanced Raman spectroscopy (SERS), by employing cysteine modified gold nanoparticles (Cys-AuNPs) as SERS probe to capture STX molecules through electrostatic interactions and multiple hydrogen bonds between Cys and STX molecules. Moreover, the XPS and zeta potential results indicated that Cys could bond to AuNPs through Au-S bonds and the addition of STX could induce the efficient aggregation of Cys-AuNPs owing to the presence of electrostatic interactions and multiple hydrogen bonds between Cys and STX molecules. Furthermore, considering the high sensitivity and stability of the dynamic surface-enhanced Raman spectroscopy (D-SERS) strategy with the formation of a 3D hotspot matrix, the highly sensitive detection of STX was realized to a level of 1 × 10⁻⁷ M by using the D-SERS strategy. Consequently, Cys-AuNPs as high affinity substrates can provide high sensitivity for the detection of STX through the D-SERS strategy.

Graphical abstract

毒毒素（STX）是最有害和典型的麻痹性贝类毒素之一，对环境和人类健康构成严重威胁，因此开发一种灵敏，可靠的STX检测分析方法至关重要。本文中，我们提出了一种策略，通过使用半胱氨酸修饰的金纳米颗粒（Cys-AuNPs）作为SERS探针，通过静电相互作用和Cys之间的多个氢键捕获STX分子，从而利用表面增强拉曼光谱（SERS）快速，灵敏地检测STX。和STX分子。此外，XPS和zeta电位结果表明，Cys可以通过Au-S键与AuNPs结合，并且由于Cys与STX分子之间存在静电相互作用和多个氢键，因此添加STX可以诱导Cys-AuNPs有效聚集。 。此外，^-7  M分别使用d-SERS策略。因此，作为高亲和力底物的Cys-AuNPs可以通过D-SERS策略为检测STX提供高灵敏度。

图形概要