Dopamine and Melamine Binding to Gold Nanoparticles Dominates Their Aptamer-Based Label-Free Colorimetric Sensing
Dopamine and Melamine Binding to Gold Nanoparticles Dominates Their Aptamer-Based Label-Free Colorimetric Sensing
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DOI：
10.1021/acs.analchem.0c01773
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发表时间：
2020-07-07
影响因子：
7.4
通讯作者：
Liu, Juewen
中科院分区：
文献类型：
--
作者：
Liu, Xixia;He, Fan;Liu, Juewen
金纳米粒子对核酸适体的靶向吸附已被广泛应用于开发无标记比色生物传感器。然而，靶分子和金纳米颗粒之间的潜在相互作用没有被考虑，这可能导致分析结果的误解。在这项工作中，检测多巴胺，三聚氰胺，和k（+）作为模型系统，以解决这个问题进行了研究。首先，多巴胺和两个控制分子都诱导柠檬酸盐封端的金纳米颗粒的聚集，其表观Kd为5.8 μ M多巴胺，51.6 μ M去甲肾上腺素和142 μ M酪胺。等温滴定量热法测得的适体K-d为1.9 μ M多巴胺和16.8 μ M去甲肾上腺素，而酪胺不能结合。表面增强拉曼光谱证实了多巴胺的直接吸附，吸附的多巴胺抑制了DNA的吸附。使用典型的盐诱导比色检测方案，观察到类似的颜色响应，而不管DNA的序列如何，表明观察到的颜色变化反映了多巴胺被AuNP吸附，而不是多巴胺被适体结合。对于这种无标记传感器的工作，目标分子和AuNP之间的相互作用应该非常弱，而多巴胺代表了强相互作用的一个例子。对于其他两个系统，三聚氰胺检测也没有反映适体结合，但K+检测，这表明三聚氰胺也强烈地与金纳米粒子相互作用，而K+与金纳米粒子的相互作用非常弱。由于每个靶分子是不同的，因此需要逐案研究这种靶/AuNP相互作用以确保传感机制。
Target directed aptamer adsorption by gold nanoparticles (AuNPs) has been widely used to develop label-free colorimetric biosensors. However, the potential interactions between target molecules and AuNPs have not been considered, which may lead to misinterpretation of analytical results. In this work, the detection of dopamine, melamine, and k(+) was studied as model systems to address this problem. First, dopamine and two control molecules all induced the aggregation of citrate-capped AuNPs with apparent K-d's of 5.8 mu M dopamine, 51.6 mu M norepinephrine, and 142 mu M tyramine. Isothermal titration calorimetry measured the aptamer K-d to be 1.9 mu M dopamine and 16.8 mu M norepinephrine, whereas tyramine cannot bind. Surface enhanced Raman spectroscopy confirmed direct adsorption of dopamine, and the adsorbed dopamine inhibited the adsorption of DNA. Using a typical salt-induced colorimetric detection protocol, a similar color response was observed regardless of the sequence of DNA, indicating the observed color change reflected the adsorption of dopamine by the AuNPs instead of the binding of dopamine by the aptamer. For this label-free sensor to work, the interaction between the target molecule and AuNPs should be very weak, while dopamine represents an example of strong interactions. For the other two systems, the melamine detection did not reflect aptamer binding either but the K+ detection did, suggesting melamine also strongly interacted with AuNPs, whereas K+ had very weak interactions with AuNPs. Since each target molecule is different, such target/AuNP interactions need to be studied case-by-case to ensure the sensing mechanism.