生物友好型磁光多功能纳米探针的制备、调控及生物检测

Magneto-optical multifunctional nanoprobes, with unique properties of magnetic, optical and electrical, have important application prospect in the fields of biodetection, bio-imaging and disease diagnosis. This project, based on the magnetic property of magnetic nanoparticles and the localized surface plasmon resonance effect of noble metallic nanoparticles, will be implemented to design magneto-optical multifunctional nanoprobes which combine three kinds of separation and detection techniques of magnetic property, surface-enhanced fluorescence and surface-enhanced Raman scattering. The functionality of single nanomaterial will be effectively assembled and amplified, and the fluorescence signal and Raman scattering signal of nanoprobes can be enhanced simultaneously. Taking fluorescent carbon nanomaterials with a stable chemical properties and low toxicity as a fluorescent signal probe will help to resolve potential environmental and health problems. The recognition of magneto-optical multifunctional nanoprobes towards proteins and tumor cells will be studied by means of magnetic and optical multi-mode detection and imaging. The results of this project will not only realize the stable control of the structure, shape, size and functionality of the magneto-optical multifunctional nanoprobes, but also provide several multifunctional nanoprobes with specific functionality and application prospect, and will establish 1-3 proteins or tumor cell identification detection methods, as well as provide new ideas and reference for the early detection, diagnosis and treatment of tumors.

磁光多功能纳米探针具有独特的磁性和光电等性质，在生物检测、生物成像和疾病诊断等领域有重要的应用前景。本项目基于磁性纳米粒子的磁性质和贵金属纳米粒子的局域表面等离子共振效应，设计磁性、表面增强荧光和表面增强拉曼散射三种分离检测技术于一体的磁光多功能纳米探针，将单个纳米材料的功能进行有效组合和放大，实现纳米探针的荧光信号和拉曼散射信号同时增强。采用化学性质稳定的低毒无污染荧光碳纳米材料作为荧光信号探针，有利于解决潜在的环境和健康问题。借助磁性和光学多模式检测和成像研究磁光多功能纳米探针对蛋白和肿瘤细胞的识别作用。通过本项研究，实现磁光多功能纳米探针结构、形貌和性能的有效控制，提供几种具有特定功能和应用前景的磁光多功能纳米探针，构建1-3种蛋白或肿瘤细胞识别检测方法，为肿瘤的早期检测和诊治提供新思路和参考依据。

具有优异光学性质的多功能纳米材料能够应用于未来的生物检测、生物成像和疾病诊断。不同纳米结构材料的巧妙结合有助于推动纳米检测平台的发展，这种多功能应用是单一组分纳米颗粒难以实现的。我们选择柠檬酸氢二胺、谷氨酸等不同的碳源，采用微波、水热或直接加热等方法制备了不同功能化的荧光碳纳米点，研究了其生物毒性，蛋白的识别检测和对肿瘤细胞的识别标记作用。构建了生物相容性的Ag/PATP@SiO2/碳点核壳纳米粒子，用于荧光和表面增强拉曼（SERS）双模式检测。结果表明，我们提出制备碳点的方法简单、绿色、快速，得到了表面具有羧基、羟基或硼酸基团的荧光碳纳米点。以柠檬酸氢二胺为碳源时，微波法制备的碳点平均粒径为2.8 nm，量子产率达到26.8%。，Fe3+离子对碳点的荧光猝灭最大，Fe3+离子浓度在0~100 μM范围内，F/F0和Fe3+离子浓度呈线性关系。碳点浓度为1.0 mg/mL时，BGC-823细胞存活率大于91%，CT26.WT细胞存活率大于82%。碳点可用于BGC-823/CT26.WT细胞标记。以草酸和尿素为碳源，采用微波方法快速合成了具有热敏性的氮掺杂碳点，在10～80 °C的温度范围内，相对荧光强度与温度之间存在良好的线性关系。以苯硼酸和无水乙二胺作为原料，通过水热法合成了表面硼酸功能化的碳点，在pH 7.4时，碳点溶液的猝灭效果与辣根过氧化酶在0～333 μg/mL浓度范围内存在线性关系。制备荧光碳点修饰的Ag@SiO2复合纳米粒子，用于荧光和SERS抗原免疫检测。优化修饰碳点和银核间隔的氧化硅壳层厚度为9 nm时碳点获得最大荧光增强。拉曼探针分子氨基苯硫酚（PATP）偶合反应产物具有较大的拉曼散射截面，明显提高SERS免疫检测灵敏度，这种双功能纳米复合粒子不仅用于高灵敏SERS和荧光抗原免疫检测，还可能在双模式生物成像领域具有潜在应用前景。