新型银纳米探针与生物辅酶NAD+/NADH的SERS特性研究

In living cells, biological molecules NAD+/NADH are critical intermediates, which widely participate in many cellular redox processes. The levels of NAD+/NADH are often considered as read out of metabolic state. Therefore, it is of considerable significance to further study the sensitive sensors to monitor them. In order to achieve ultra-sensitive detection of NAD+/NADH and real-time recognition of NAD+/NADH ratios, theoretical calculation, experimental measurements, and big data process are employed to systematically study the surface enhanced Raman scattering (SERS) features of biological coenzymes NAD+/NADH using novel silver nano-sensor. Owing to the interesting π-π stacking interaction between silver nano-sensor and NAD+/NADH, high quality SERS signals of NAD+/NADH are rapidly obtained by high affinity between the coenzymes and Ag NPs. It is worthy to note that, in low detection levels, two Ag NPs are spontaneously bridged to form a dimer through π-πstacking interactions, due to two special moieties (adenine, nicotinamide) of NAD+ molecule. In this project, with the help of dimer, the Raman mapping method is employed to obtain the distribution imaging of SERS signal from NAD+/NADH, and to implement the ultra-sensitive detection for NAD+/NADH. In addition, big data process is also applied to study and extract the fingerprint spectra features, which can be used to identify and distinguish different NAD+/NADH ratios in real time. All in all, the implementation of the project is expected to extend and develop the sensitive detection technology of biological coenzymes, and it can provide significant reference and guidance for intracellular living detection in life science field.

NAD+/NADH是胞内关键的媒介，参与多个氧化还原反应，其含量是新陈代谢的主要指标，开展NAD+/NADH灵敏探测研究具有重要的科学意义。本课题通过理论计算、实验测量以及大数据分析的手段，研究新型银纳米探针与NAD+/NADH的SERS特性，拟实现NAD+/NADH超灵敏探测和不同NAD+/NADH比值在线识别的目标。该探针与NAD+/NADH存在有趣的π-π堆积作用，具有很强的吸附性，可以快捷地探测出高质量SERS信号。低探测水平下，NAD+/NADH官能团腺嘌呤和烟酰胺能自发地捕获两个纳米颗粒形成二聚体。借助于二聚体电磁增强效应，本课题通过拉曼成像绘制NAD+/NADH 的SERS信号分布图像，实现其超灵敏探测。本课题开发大数据分析方法，分析并提取其指纹特征光谱信息,实现不同NAD+/NADH比值的实时判别。本研究可望拓展并完善生物辅酶的灵敏探测技术，对活体探测有重要的指导意义。

芳香族生物分析物（例如，DNA碱基、辅酶因子NAD+/NADH、细胞因子以及蛋白分子等）是生命活动的关键媒介。因此，对其开展超灵敏探测的研究具有重要的科学意义。借助于π-π堆积作用吸附机制，作本项目通过设计、开发并制备多种超灵敏等离子体传感探针，采用表面增强拉曼光谱技术和表面等离子体共振传感技术实现了对芳香族生物分子超灵敏探测(＜1pM)的研究目标。本项目设计的等离子体传感探针主要有PSSS-MA-templated Ag NPs、新型银纳米三角棱柱和二维材料增敏的传感界面（金膜-黑鳞-石墨烯复合结构、铝膜-石墨烯复合结构、银膜-二氧化硅-六方氮化硼复合结构，银膜-Ti3C2Tx MXene-石墨烯复合结构以及金膜-锑烯-石墨烯-SnSe复合结构），在超灵敏生物传感领域有广泛应用前景。此外，本项目还制备了新型磁性光热材料MnFe2O4-NaYF4，具有良好的稳定性、生物兼容性以及较高的光热转换效率。在近红外光照射下，该磁性纳米粒子能够有效抑制小鼠肿瘤的生长，在生物医学和癌症治疗领域有广泛的应用前景。