基于巯基嘌呤/多肽修饰的金纳米粒子的比色方法检测溶液中的镉离子

研究了一种基于双配体（巯基嘌呤（MP）和多肽CALNN）修饰金纳米粒子（AuNPs）的比色方法，用于快速、选择性地检测水溶液中的Cd2+。 其中，MP作为功能配体通过N原子与Cd2+发生配合作用，从而引起AuNPs聚集；CALNN配体有助于提高体系的稳定性和选择性。 当体系中无Cd2+时，溶液呈红色，随着Cd2+浓度的增加，溶液颜色逐渐由红色变为蓝紫色，这种颜色变化可以通过光谱测定还可以用肉眼直接观察。 该方法操作简便，具有较好的选择性和较快的响应速度（＜5 min），其检测限达到350 nmol/L。

A Simple Colorimetric Assay for Detection of Cadmium Ion Based on 6-Mercaptopurine/peptide Functionalized Gold Nanoparticles

A simple colorimetric assay for rapid and selective sensing toxic heavy metal ion, cadmium ion(Cd2+), has been developed using gold nanoparticles(AuNPs) decorated with 6-mercaptopurine(MP) and peptide CALNN. MP is employed as a chelating ligand through the N group at the end of MP, and CALNN is served not only as a stabilizer, but also as a factor of high selectivity. AuNPs solution exhibits a gradual color change from red to blue with increasing the concentration of Cd2+, which leads to an easily measurable change in absorption spectrum of AuNPs solution and naked eye detection. A simple assay with high selectivity and fast response(within 5 min) is presented, and the limit of detection(LOD) for Cd2+ was calculated to be 350 nmol/L.