Colorimetric detection of D-amino acids based on anti-aggregation of gold nanoparticles
Colorimetric detection of D-amino acids based on anti-aggregation of gold nanoparticles
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DOI：
10.1016/j.cclet.2014.06.002
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发表时间：
2014-07
影响因子：
9.1
通讯作者：
Longfei Yuan;Yujian He;Hong Zhao;Ying Zhou;Pei Gu
中科院分区：
文献类型：
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作者：
Longfei Yuan;Yujian He;Hong Zhao;Ying Zhou;Pei Gu
提出了一种在氨基酸氧化酶（DAAO）存在下，利用4-巯基苯甲酸修饰金纳米粒子（AuNPs）的抗聚集性实现d-氨基酸（DAAs）视觉检测的新方法。以柠檬酸钠为还原剂和稳定剂制备了带负电荷的aunp。4-巯基苯甲酸（4-MBA）和Cu2+的存在诱导了aunp的聚集，导致颜色从宝石红变为宝紫色。而DAAO可以氧化DAAs生成H2O2。在H2O2存在下，4-巯基苯甲酸中的巯基（单键sh）基团可被氧化形成二硫键（单键sh）键。基于这些事实，DAAs和4-巯基苯甲酸与DAAO预孵育会显著降低游离4-巯基苯甲酸分子的浓度，因此由于缺乏诱导剂，AuNPs的聚集被中断。随着DAAs浓度的增加，AuNPs溶液的颜色会从紫红色变为红宝石红色。因此，DAAs可以通过使用紫外-可见分光光度计甚至肉眼通过AuNPs的比色响应来监测。这种DAAO介导的目视检测方法可以检测到-丙氨酸（d-Ala）为代表性DAA，其浓度范围为1.5 × 10−7mol L−1 ~ 3.0 × 10−5mol L−1，检出限低至7.5 × 10−8mol L−1。该方法简便、成本低、不需要复杂的设备，可用于β-淀粉样肽（a - β1 - 42）样品中d- ala的浓度分析。
A new method has been proposed to realize the visual detection ofd-amino acids (DAAs)viathe anti-aggregation of 4-mercaptobenzoic acid modified gold nanoparticles (AuNPs) in the presence ofd-amino acid oxidase (DAAO). The negatively charged AuNPs were prepared using sodium citrate as a reducer and stabilizer. The presence of 4-mercaptobenzoic acid (4-MBA) and Cu2+induces the aggregation of AuNPs, resulting in a color change from ruby red to royal purple. However, DAAO could oxidize DAAs to generate H2O2. In the presence of H2O2, the mercapto (single bondSH) group in 4-mercaptobenzoic acid can be oxidized to form a disulfide (single bondSsingle bondSsingle bond) bond. Based on these facts, the pre-incubation of DAAs and 4-mercaptobenzoic acid with DAAO would significantly reduce the concentration of free 4-mercaptobenzoic acid molecules, thus the aggregation of AuNPs was interrupted since due to the lack of inducer. As the concentration of DAAs increases, the color of the AuNPs solution would progress from royal purple to ruby red. Consequently, DAAs could be monitored by the colorimetric response of AuNPs using a UV–vis spectrophotometer or even naked eyes. This DAAO mediated visual detection method could determined-alanine (d-Ala) as a representative DAA with concentrations ranging from 1.5 × 10−7mol L−1to 3.0 × 10−5mol L−1, and the detection limit was as low as 7.5 × 10−8mol L−1. The proposed method is convenient, low-cost and free of complex equipment, making it feasible to analyze the concentration ofd-Ala in real samples ofβ-amyloid peptide (Aβ1–42).