基于碳点的高分子纳米粒子的制备及其对内源性生物物质的荧光检测与示踪

Endogeous bioactive substances including metabolic enzymes are of great significance in terms of physiological functions and pathological roles. Fluorescent sensing and tracking of metabolic/diagnostic enzymes are helpful for disease diagnosis as well as searching for effective treatments. In order to address the existing issues in this field, herein we plan to employ carbon dot as both the energy donor and the anchoring site for the recognition-chromohpore containing polymer; the said polymer consists of two blocks, one block contains the recognition moieties (namely the recognition-chromophores, which can serve as the energy acceptor upon reaction with specific metabolic enzyme depending on the structure of the recognition moiety), while the other block is hydrophilic and biocompatible, thus a series of FRET systems can be constituted for diagnostic enzymes. Through rationally designing the polymer chain structure, the chromophore structure, as well as the spacer between polymer chain and recognition moiety, in the mean time by modulating the interactoins of the system, highly efficient enzymatic reactions and energy transfer can be realized. Furthermore, we will apply the fluorescent sensing systems to various biological samples, so as to detect specific enzyme levels via fluorescent ratiometric sensing, and investigate the systems' accuracy and specificity. In addition, we will optimize the systems' cytoxicity and cell membrane permeability, and invesitgate their potential for intracellular imaging of metabolic enzymes and sensing intracellular enzyme levels. This study will offer effective approaches for modulating the energy transfer behavious and sensing functions of the particle/chromophore-containing polymer systems, as well as for realizing sensitive detection of metabolic enzymes, and thus extend the applications of polymeric systems.

内源性生物活性物等具有重要的生理和病理作用，对一些内源性生物物质的荧光检测可为重大疾病的发生和发展提供判据，并为临床治疗提供有效信息。为了克服在该领域尚存的一些问题，本研究拟以碳点和/或高分子基体为能量供体和检测体系的载体，将含识别基团的嵌段共聚物连接到碳点表面，构建一系列基于FRET原理的不同生物物质的分析体系。通过对聚合物分子链、识别基团及其与大分子之间的间隔基的合理设计，并对体系的相互作用进行有效控制，实现高效的酶促反应和能量转移过程。获取不同个体的生理液样本，对特定生物物质的浓度进行荧光比率检测，考察体系对实际样品检测的准确性和专一性。研究并优化体系的细胞毒性和细胞膜透过性，探讨荧光检测体系对活细胞内生物物质的荧光成像，以反映胞内生物物质的浓度水平。通过本项目的开展，我们希望能掌握荧光粒子/含荧光生色团大分子体系中能量转移行为及检测功能的调控方法，实现对内源性生物物质的高效检测，从而拓展高分子体系的应用范围。

一些生物物质与诸多生理过程和/或病理过程密切相关，为此这些物质可作为一些疾病的生物标志物。对于可作为生物标志物的内源性物质的检测对于疾病的早期诊断、病理分析等具有重要意义。另一方面，有毒有害物质（工业有毒气体或军事毒剂、金属离子等）威胁环境和公共安全，因此对于有毒有害物质的便携灵敏检测在环境保护与监测和防恐安全等方面具有重要的应用前景。本项目制备构建了基于碳点和高分子为基体的功能性荧光体系，考察了这些体系对于这些物质的检测；通过在荧光化合物上引入针对不同被检物（如醌还原酶、气体信号递质等）的响应基元，利用纳米探针体系实现了对内源性生物物质及气体信号递质等的荧光检测与示踪；利用高分子优异的成膜性，制备了便携式的荧光检测体系，用于有毒有害气体和金属离子等物质的检测。此外，在高分子纳米体系中引入内源性和外源性的触发基元，利用外源性和内源性触发机制实现了对药物的可控可调的释放及对药物释放的荧光示踪，并探讨了体系的诊断与治疗相结合的功能；构建了可对病灶区过度表达的酶响应的纳米体系，通过内源性的过度表达的酶作为促发机制，诱发连锁消除反应，从而同时释放药物和荧光团，通过荧光信号跟踪药物的释放及评价疗效。研究结果可望对有毒有害物质和一些生物标志物实现灵敏检测，并可应用于环境监测/防恐安全和病理分析等领域，此外可为进一步设计灵敏便携的荧光检测体系提供一些有益的参考。