基于信号协同放大策略的纳米探针荧光成像及传感的分析新方法研究

It has become the future direction of the emitting nano-probes to using environmentally friendly materials such as carbon and silicon instead of traditional contained heavy metals, meanwhile, the emitting properties of nano-materials are the key to the sensitivity of analysis methods. Respond to trace amount of the analysis objects in life and environment samples or other complex samples, the proposed project put forward to develop high sensitivity detection methods based on collaborative signal amplification to detect tumor markers. The detailed studies as follows: to develop multi-fluorescent and single-binding site probes using carbon or silicon fluorescence material with core-shell and dendrimer structure, capsules or holes coating, or other means; realize the fluorescence signals amplified through magnetic separation, sandwich-style assemble, fluorescence resonance energy transfer between the probes and the analytes etc; design the different nucleic acid rolling-cycle reactions between the probes and targets to virtually increase the concentration of the analytes; To research various signal amplification strategies for synergistic amplification effect and apply them in fluorescence imaging and sensing of tumor markers such as alpha fetal protein (AFP) , carcino embryonie antigen (CEA). The research devoted to solve the problem of the weak fluorescence of carbon or silicon in order to meet the complex life samples with high sensitive, the results will generate significance in theory and application of detecting very low analytes in complex samples with optical nanoprobes.

环境友好材料碳和硅替代有重金属污染的材料是发光探针的发展方向之一, 但目前碳、硅纳米材料的发光强度难以满足高灵敏度探针的要求。为了应对生命、环境等复杂样品中含量极低的分析对象，本项目基于测量信号协同放大的策略，利用碳和硅发光探针建立肿瘤标志物的高灵敏度检测新方法。研究内容包括采用核壳结构和掺杂的方法合成碳、硅发光材料，运用各种组装方式制备多发光体单识别位点的探针；通过富集分离、“三明治”式组装、荧光共振能量转移等方式实现探针与分析物之间相互作用的信号放大；通过核酸信号放大技术构建探针与分析目标之间的循环反应；协同多种信号放大策略，实现信号级联放大并应用于甲胎蛋白、癌胚蛋白等肿瘤标志物的荧光成像与传感分析，形成低含量靶标信号放大通用检测模型。研究成果将解决碳和硅发光信号不强的问题，满足复杂生命样品高灵敏度的要求，对纳米光学探针解决复杂体系中低浓度靶标分析具有理论和应用价值。

为了应对生命、环境等复杂样品中含量极低的分析对象，本项目基于测量信号协同放大的策略，利用生物相容性好的材料制备各类信号探针，建立多种分析物的高灵敏度检测方法。项目的主要研究内容包括：用不同手段和方法合成了硅纳米、碳纳米、银纳米发光探针，通过掺杂、改性等手段提高其发光强度；研究探针与分析对象相互作用方式不同产生信号放大的策略，这些策略包括主客体间的配位产生荧光信号的“天线效应”、荧光共振能量转移、分离富集等；建立了多种生化样品的高灵敏检测新方法，并将这些方法应用于实际样品。以硅纳米探针为例，通过微波法制备比水热法荧光强度高出数倍SiNPs，为了进一步提高硅纳米探针的发光强度，在其表面修饰Eu(Ⅲ)离子得到荧光强度明显增强且具有双发射的探针SiNPs/Eu，实验证明金霉素（CTC）与SiNPs/Eu相互作用方式是通过CTC与Eu（III）进行配位，这种相互作用方式使探针中Eu(Ⅲ)的发射峰强度显著增大，出现“天线效应”，该方法检出限比单独用SiNPs测定的检出限降低约1000倍。本项目的研究表明协同信号放大能明显提高分析方法的灵敏度，解决分析样品待测物含量低的问题。