定制糖配体修饰金纳米探针及其基于肿瘤标志蛋白Galectin-1的血清学检测研究

It is well recognized that early diagnosis and treatment of tumors can upgrades the prognosis and survival of cancer patients. There are abundant techniques for the early and confirmed diagnosis of specific cancers. However, diagnostics for broad-spectrum tumor screening are still lacking, hence should be further developed. The glyco-gold nanoprobe technology provides a potential broad-spectrum tumor screening approach by the specific binding interactions between universal tumor biomarkers and their glyco-ligands. The fascinating advantages of glyco-gold nanoprobes makes it worth being further studied and developed as a novel low-cost, fast and simple diagnostic technique. Unfortunately, the existing glyco-gold nanoprobes commonly subject to the weak binding interactions between glyco-ligands and target proteins, resulting in relatively low sensitivity and specificity when applied in complicated physiological and serological assays. Here in this study, based on the mechanism of binding interactions between the universal tumor biomarker Galectin-1 and its carbohydrate ligands, a further study is proposed where the ligands attached on gold nanoparticles are structurally tailored to improve the sensitivity and specificity of bioprobes. The probes are further subjected to the screening of cancer patients with high serum level of Galectin-1. By understanding the relationship of tailored carbohydrate ligands and its improvement to the sensitivity and specificity of bioprobes in complicated physiological environment, one or several novel clinical diagnostic gold nanoprobes with high sensitivity and specificity can be developed, as well as the new assay methods for clinical cancer screening.

早诊早治对改善癌症患者预后、提高生存率有重要作用，目前针对具体癌症的早筛和确诊手段丰富，但缺乏广谱肿瘤普筛技术，发展广谱肿瘤初筛技术意义重大。基于广谱肿瘤标志物与其糖配体识别结合的糖-金纳米探针技术为广谱肿瘤初筛提供了新思路，并有发展成为一类具有低成本、快速、简单有效等特点的新型诊断技术潜质。针对现有糖-金纳米探针普遍基于天然糖配体对靶蛋白低特异识别、低亲和结合，在复杂生理检测环境中灵敏度和特异性不够的关键问题，本项目将结合广谱肿瘤标志物Galectin-1的糖结合域口袋与糖配体识别结合作用原理，对糖配体进行结构定制修饰，进而将定制糖配体固定于金纳米粒表面构建糖-金纳米探针，进行血清Galectin-1检测肿瘤诊断研究，探索糖配体结构定制修饰对提高探针在复杂检测环境中的灵敏度、特异性等关键性能的作用机制，获得一类具有临床应用价值的肿瘤诊断金纳米探针，并依此研发出一类新型临床肿瘤初筛方法。

早诊早治对改善癌症患者预后、提高生存率有重要作用，目前针对具体癌症的早筛和确诊手段丰富，但缺乏广谱肿瘤普筛技术。本项目通过研究糖-金纳米探针检测血液中广谱肿瘤标志物半乳凝素-1(Gal-1)蛋白来探索发展肿瘤普筛快检技术，主要过程为探针表面糖配体识别结合Gal-1引发金纳米探针聚集、产生明显光学信号变化、快速判定检测结果。针对现有糖-金纳米探针在复杂生理环境中检测Gal-1灵敏度和特异性不够的关键问题，本项目从抑制探针非特异性干扰和提高探针检测特异性方面展开研究，主要内容包括：1)构建天然糖配体-金纳米探针并进行Gal-1检测研究；2)金纳米探针表面改性降低非特异性干扰；3)探针表面糖配体结构修饰提高检测性能。取得的主要成果包括:1)在团队前期研究基础上，再次证明利用糖配体检测Gal-1具有可行性，将其成功扩展至电化学检测，通过构建乳糖-金-氧化亚铜复合纳米探针、利用探针的电化学特性对Gal-1进行检测; 2)阐明了复杂血清环境对金纳米探针的非特异性干扰过程，并通过巯基-疏水链-两性离子亲水头的稳定分子设计，将金纳米颗粒表面改性为疏水层-两性离子亲水层仿生结构，该结构通过稳定的S-Au键螯合固定于探针表面，其外层两性离子基团极大降低了血清中高浓度背景蛋白对金纳米探针的非特异性于扰; 3)根据现有Gal-1识别结合糖配体的研究结果，对探针表面糖配体进行结构修饰，合成获得结构定制的高亲和糖配体，将其固定于金纳米颗粒表面，构建定制糖配体-金纳米探针，该探针在抵抗血清背景蛋白非特异性干扰同时，初步表现出明显优于天然乳糖配体-金纳米探针的检测特异性和灵敏度优势，目前该部分研究工作正处于临床血样检测研究的关键阶段，相关研究成果再后续将以研究论文、专利等形式进一步补充至本项目，充实项目研究成果。