基于磁性双发射碳量子点分子印迹探针的构建及对类固醇选择性识别

Steroids are widely used in livestock and poultry industry. However, the abuse of steroids can cause endocrine disorders in human. Thus, it is essential to develop probes for simple, rapid and efficient determination of steroids. In this proposal, we aim at designing a fluorescent probe with specific recognition for efficient detection of steroid compounds in foods, as well as further understanding of the mechanisms. The probe consist of bio-based fluorescence ratiometric quantum dots serving as fluorometric reporter and molecularly imprinted polymer (MIP) functioning as recognition unit. The dual-emission carbon quantum dots (d-CQDs) are covalently conjugated to the surface of the amino modified Fe3O4 via carbodiimide chemistry to form magnetic-ratiometric fluorescence dots (d-CQDs@Fe3O4). Mesoporous silica based magnetic-ratiometric fluorescent molecular imprinting (MIP@d-CQDs@Fe3O4) is prepared by immobilizing molecularly imprinted polymer on the surface of d-CQDs@Fe3O4. The as-prepared MIP@d-CQDs@Fe3O4 has mesoporous-structure and specific recognition properties. Furthermore, the effect of molecularly imprinted structure, mesoporous silica and mechanism of fluorescence quenching will be systematically studied. The MIP@d-CQDs@Fe3O4 probe not only can play an important role in steroid analysis in food, but also is potentially useful in field analysis.

类固醇在畜禽类食品中得到广泛的应用，但类固醇的滥用容易引起人体内分泌系统紊乱。因此，建立一种更简便、快速检测类固醇的方法尤为重要。项目拟构建特异性荧光探针，实现食品中类固醇化合物的高效检测，并探讨其作用机理。该荧光探针选择生物质材料制备的比率荧光量子点作为信号单元，介孔硅型分子印迹聚合物作为识别单元。探针的构建先用氨基化的四氧化三铁和双发射碳量子点通过共价键结合，形成磁性比率荧光量子点。然后在磁性比率荧光量子点表面偶联分子印迹聚合物，形成具有特异性识别功能的介孔硅型比率荧光分子印迹聚合物。我们还将系统研究分子印迹孔穴结构、介孔结构在检测中的具体作用机制以及荧光猝灭原理。该项目的实施，不仅可以实现食品中类固醇化合物的检测，在现场分析中也有广阔的应用前景。

本项目结合分子印迹技术、视觉荧光分析系统和磁性吸附分离系统的优点，构建了比例荧光磁性分子印迹探针。在这种体系中，该探针具有分子印迹体系的快速特异性识别特性，比率荧光体系的高灵敏性和自校正特性，磁性体系耦合分子印迹技术的快速预吸附和分离富集的优势。提出了生物质材料制备的多色比率荧光量子点作为信号单元，介孔硅型分子印迹聚合物作为识别单元，系统探讨了分子印迹孔穴结构在检测中的具体作用机制以及目标分子荧光猝灭的相关机制。此外，基于智能手机读取光学信号的原理，通过密度泛函理论计算，结合人工智能图像识别算法，自主研发多色荧光App分析系统，成功构建一种基于智能手机便携式可视化荧光和比色传感系统。对该传感体系的稳定性和抗干扰特性进行了研究，证明了基于智能手机便携式可视化光学传感体系的实际应用潜力，有助于实现对类固醇激素、抗生素、农兽药分子、重金属离子等有毒有害物质的痕量、快速原位监测，在食品安全和环境保护中具有一定的重要意义。