SERS结合核磁共振氮谱研究嘌呤碱基在金/银溶胶表面的吸附状态

Surface enhanced Raman spectroscopy (SERS) combined with density functional theory (DFT) calculation is an effective method to solve the adsorption configuration problem of simple molecules with few adsorption sites and few tautomers adsorbed on the surface of gold/silver colloidal nanoparticles. However, for most biological molecules, there are many possible adsorption configurations, therefore it is difficult to apply this method effectively. In this project, we will investigate the adsorption of biological molecules with more adsorption sites and more tautomers like purine bases. Based on our previous used the SERS combination DFT method, in this project, we will additionally employ the nitrogen-15 nuclear magnetic resonance (NMR) spectroscopy combined with DFT in order to establish a multi-dimensional efficient and reliable method and strategy for the analysis of the adsorption configurations. This method relies on the intuitive regularity between the nuclear magnetic resonance nitrogen spectrum and the adsorption structure, can therefore effectively remedy the shortcomings of the old method in the analysis of complex systems, such as heavy workload in computation, uncertainty and controversy in determining the adsorption configuration. It helps to determine the states including the surface bonding and tautomerism of purine bases adsorbed on gold/silver nanoparticles, to better understand the adsorption states of protonation and deprotonation of purine bases under acidic and basic conditions. Therefore, this project may provide the experimental and theoretical basis for solving the adsorption problem for biomolecular gold/silver colloid complex system and related physical and chemical problems.

表面增强拉曼光谱（SERS）结合密度泛函理论（DFT）计算的方法是目前解析吸附位点少且异构体少的简单分子在金/银溶胶表面吸附构型问题的有效方法。但是对许多生物分子来说，其可能的吸附构型多，所以该方法的推广使用面临较大困难。本项目拟以嘌呤碱基这样吸附位点多且互变异构体多的生物分子为例，在原有SERS结合DFT的方法基础上,引入核磁共振（NMR）氮谱及其DFT谱学计算的方法，以构建一套多维度高效可靠的吸附构型解析方法和策略。该方法凭借核磁共振氮谱与吸附结构之间的直观规律性对应联系，可有效弥补原方法解析复杂体系工作量大、不确定性高和争议多的缺点，可有助于明晰嘌呤碱基在金/银纳米颗粒表面吸附后的表面成键、互变异构的状态，加深理解嘌呤碱基在酸碱条件下发生质子化和去质子化的吸附状态，从而为解决生物分子-金/银溶胶复杂体系的吸附问题及有关物理化学问题提供实验和理论依据。

由于生物分子和杂环分子的结构复杂，其在贵金属表面吸附时可能的吸附构型多，所以传统方法较难确定分子构象和表面吸附构型。理解贵金属表面与生物分子之间相互作用的行为机制是纳米材料学、生物学、化学、医学、物理学等众多学科交叉融合产生的重要共性研究内容。本项目综合了拉曼光谱、核磁共振、红外光谱等谱学方法和密度泛函理论，构建一套多维度高效可靠的生物分子构象和吸附构型解析方法和策略。分子体系包括嘌呤、虾青素、赖氨酸、喹啉、烯醇等生物分子和含氮杂化分子。研究工作通过理论结合实验的方式，明确了腺嘌呤和鸟嘌呤在金银溶胶表面的吸附方式；提出了全反式虾青素3种光学异构体的光谱鉴别方案；提出了10种虾青素几何顺反异构体的拉曼和红外光谱鉴别方法；提出了赖氨酸分子及多肽中赖氨酸残基乙酰化的拉曼和红外光谱识别方法；明确了8甲基喹啉在多种钯催化剂表面的吸附行为；明确了2-甲基-烯醇在多种元素掺杂钯催化剂表面的吸附方式；提出两种抗生素的快速光谱检测方法。相关工作对生物分子光谱和结构的基础研究具有重要的意义，也为相关体系在检测分析、催化、医药健康等领域方面的应用提供理论基础。已在Spectrochimica Acta Part A、Nature communications等期刊上发表了6篇项目标注的学术论文，其中第一作者论文3篇，另外有两篇论文在撰写投稿中。

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