Development of a strategy for the optical detection of anions in water by using surface-modified gold nanoparticles

在这项研究项目中，将开发一种依赖于将已知的阴离子受体固定在水溶性金纳米颗粒表面的方法来光学检测水中的无机阴离子。在没有它们各自的分析物的情况下，这些纳米颗粒将以非聚集的形式驻留在溶液中，它们的大小将引起等离子体共振，使溶液呈现出特有的颜色。在适当的无机阴离子存在下，由于纳米粒子的聚集，这种颜色会发生变化。聚集将由结合在纳米颗粒表面的受体与其阴离子底物之间的特定相互作用引起。这种体系的优点是检测灵敏度，这是纳米颗粒聚集的多价相互作用的影响，以及检测选择性，可以由表面结合受体的类型控制。将使用的阴离子受体将基于本小组开发的阴离子结合环肽或其他所述类型的受体。这项工作将主要针对饮用水或地下水中典型的阴离子水成分的检测，如硫酸盐、磷酸盐和氯离子。此外，有毒的砷酸根离子也将被视为分析物。涉及纳米颗粒表面组成和结合受体类型变化的系统研究将表明，该项目背后的概念是否允许在存在潜在竞争分析物的情况下，以足够的选择性检测水中相关浓度的阴离子。因此，应该可以在项目结束时估计这种检测系统是否有实际应用，例如用于饮用水中砷酸盐的简便定性检测。

A strategy will be developed in this research project for the optical detection of inorganic anions in water relying on the immobilization of known anion receptors on the surfaces of water-soluble gold nanoparticles. In the absence of their respective analytes, these nanoparticles will reside in solution in non-aggregated form and their size will give rise to a plasmon resonance causing the solution to exhibit a characteristic color. This color will change in the presence of suitable inorganic anions because of nanoparticle aggregation. Aggregation will be caused by specific interactions between the receptors bound to the surface of the nanoparticles and their anionic substrates. Advantages of such systems are the detection sensitivity, which is an effect of the multivalent interactions underlying nanoparticle aggregation and the detection selectivity, which can be controlled by the type of surface-bound receptor. Anion receptors that will be used will either be based on the anion-binding cyclopeptides developed in the own group or on other described types of receptors. The work will mainly aim at the detection of anionic water constituents typically present in drinking or ground water such as sulfate, phosphate, and chloride anions. In addition, toxic arsenate anions will also be considered as analytes. Systematic investigations involving the variation of surface composition of the nanoparticles and the type of bound receptor will show whether the concept underlying this project will allow the detection of anions in their relevant concentrations in water with sufficient selectivity even in the presence of potentially competing analytes. Thus, it should be possible to estimate at the end of the project whether practical applications exist for such detection systems, for example for the facile qualitative detection of arsenate in drinking water.