基于荧光有机纳米粒子的双重信号传感研究

Currently, fluorescence sensing is usually based on single fluorescent signal, which is the change of total fluorescent intensity (or the intensity of a certain emission peak) resulted from the interaction between fluorescent molecules and the analyte. Some fluorescent probes with multiple emission peaks can make a response when the polarity of surrounding molecules is changed. It results in the relative intensity of various vibronic transition emissions changing with the polarity. More accurate detection and measurement of analytes can be realized if dual-signal sensing, which measures the change of total fluorescent intensity (signal I) and the relative intensity of various vibronic transition emissions (signal II), can be achieved. Fluorescent organic nanoparticles (FONs) have better fluorescent characteristics than molecular probes. Therefore, FONs have brilliant application potentials. In this project, we will synthesize conjugated organic compounds with multiple fluorescent emission peaks. Then, FONs based on these compounds will be prepared. In addition, the impact of the polarity vector in surrounding environment on the relative intensity of various vibronic transitions of FONs will be investigated. Furthermore, the structure-property relations of the molecular structures of conjugated compounds constituting the FONs and their fluorescent responses to polarity will be explored. Lastly, dual-signal sensing system using FONs with good polarity response will be constructed.

目前荧光传感通常是基于单一荧光信号，即利用荧光分子与被检测物之间的相互作用，通过监测其荧光总强度（或某一特定发射峰强度）的变化来实现的。某些具有多重荧光发射峰的荧光探针会对周围分子极性的差异做出响应，体现为不同跃迁发射峰的相对强度发生改变。如果在检测荧光总强度变化（信号I）的同时，还能检测荧光探针的不同跃迁发射峰之间相对强度变化（信号II），即实现双重信号传感，则可以对被分析物进行更精准的识别与检测。有机荧光纳米粒子相对于分子荧光探针具有更好的荧光特性，故在传感领域有着很好的应用前景。本项目中我们将合成具有多重荧光发射峰的共轭有机化合物，以其制备荧光有机纳米粒子，调查纳米粒子外围环境中极性矢的大小对其不同跃迁发射峰相对强度的影响，探索构成纳米粒子的共轭有机化合物的分子结构与其荧光发射峰的极性响应特性之间的结构-属性关系，进而选择具有较好极性响应性的荧光有机纳米粒子构建出新型的双重信号传感。

荧光有机纳米粒子由于具有材料种类多，易调节修饰及光稳定性好等特点，非常适合于化学和生物体系的荧光检测。在本课题的研究中，我们设计合成了多种具有多重荧光发射峰的共轭有机化合物。该类荧光物质的荧光受周围微观环境的变化影响较大。当其周围的微观环境发生变化时，该类分子的荧光发射峰的强度会发生明显改变。我们采用所合成的荧光共轭化合物，设计制备出了多种具有多重荧光发射峰的有机荧光纳米粒子。通过改变荧光纳米粒子周围环境，研究纳米粒子的荧光发射峰对周围环境的响应性，从而发现构成纳米粒子的荧光共轭有机化合物的分子结构与其荧光发射峰的响应特性之间的内在机理关系。荧光有机纳米粒子的表面结构特性，会直接影响其荧光发射的性能及对检测物的识别性能。我们通过选择具有合适的功能性基团的化合物，以及采用聚合物电解质的层层自组装方法，可以在荧光有机纳米粒子的表面进行功能性的修饰，从而可实现该体系对检测物及分析物的高效识别及吸附。我们选用性能优异的具有环境响应性的荧光有机纳米粒子材料，构建出了具有多重荧光信号响应性的荧光检测传感体系，并将该体系成功应用于各种化学及生物材料领域的高效精准的识别与检测。