蛋白尺度多功能分子印迹聚合物的合成和多模态成像

Early diagnosis of tumor has become the most difficult yet urgent problem of the world. Targeting molecular imaging tracers are the effective methods commonly used in the early diagnosis of cancer, and the targeting was achieved through the specific antibodies or aptamers. However, the aptamers are susceptible to degrade in vivo in the presence of DNA enzyme, and the specific antibody is expensive, difficult to obtain, and unstable or even inactivated upon the labeling to the fluorescent or magnetic resonance probes. Molecularly imprinted polymers (MIPs) have the merits of predetermined selectivity, easy-synthesis and good stability, but suffering from the poor-biocompatibility, the dilemma of the small size and fine recognition of the template and the difficulty to obtain large amount of template molecules for proteins imprinting, the application of MIPs in the field of molecular imaging is still rare. The project intends to develop the novel strategies to synthesize the protein-scale, multi-peptides imprinted, hydrophilic MIPs with photoluminescent/magnetic resonance signals for in-vivo detection and multimodal imaging of human nucleolin, using the new MIPs matrix and the new polymerization reactions. The implementation of the project would provide a new method for the synthesis of protein-size MIPs with high selectivity and then achieve the transition of artificial plastic antibody into the real antibodies.

肿瘤早期诊断已成为全世界面临的重大难题和急需解决的科学问题。靶向分子影像探针示踪是癌症早期诊断中普遍采用的有效方法之一，其靶向定位一般需借助各种特异性抗体、适配体等。然适配体在生物体内易被DNA酶降解，而特异性抗体不仅难以获得、制备周期长、价格昂贵，在标记到荧光或磁共振探针上时还容易导致抗体的活性降低甚至失活。分子印迹聚合物（MIPs）具有选择性高、合成简单、稳定性好的优点，但由于生物相容性、材料尺寸与识别性能相互制约、模板分子等问题，MIPs在分子影像领域的靶向应用还很少。本项目拟以人核仁素为对象，采用MIPs新基质和新聚合模式，发展一种合成蛋白尺度、多个特定短肽印迹、亲水、具有发光和/或磁共振响应的MIPs的新策略，实现活体中MIPs对人核仁素蛋白的原位探测和靶向多模态成像。该项目的实施能提供一种新的合成高选择性的蛋白尺度MIPs的新方法，使人工塑料抗体真正具有真实抗体的功能。

项目以癌症标志物核仁素蛋白和成纤维细胞激活蛋白(FAPα)的高灵敏、低背景检测为目标，提出了两种构建发光探针的新策略，即磁分离辅助荧光共振能量转移（MS-FRET）禁阻的策略和余辉共振能量转移（ARET）免原位激发检测策略，分别实现了上述两种标志物的细胞原位高灵敏探测。项目详细探讨了上述两种策略中的关键因素，对丰富发光探针的构建策略和应用具有重要的推动作用。.项目还探究了蛋白尺度分子印迹聚合物（MIPs）的新型发光内核，即兼具尺寸小、水分散性好和超长余辉性能的铬掺杂镓酸锌（ZGO）纳米粒子的合成方法，该法简单，仅用EDTA后腐蚀即可同时调控长余辉纳米粒子的粒径、水分散性和陷阱深度。项目详细考察了腐蚀条件（EDTA用量、pH、温度），研究了腐蚀和深陷阱产生机理，比较了腐蚀前后的ZGO和ZGO-EDTA纳米粒子在小鼠成像、信息存储中的应用效果。该EDTA后腐蚀方法在减小ZGO的粒径、改善其水分散性的同时能增加中等陷阱的密度和产生深陷阱，因此能延长余辉寿命。由该法合成的ZGO纳米粒子在小鼠成像、信息存储、高温防伪、余辉辅助表面增强拉曼、昼夜催化染料降解等方面均具有广阔的应用前景。