β-环糊精修饰硫化银量子点的合成与近红外二区成像应用

APreparation ofβ-cyclodextrin modified Ag_(2)S quantum dots for NIR-Ⅱimaging

以单(6-巯基-6-去氧)-β-环糊精为稳定剂,在水溶液中制备了环糊精修饰的近红外二区(NIR-Ⅱ)发光的Ag_(2)S量子点。系统研究了银和硫的比例、β-环糊精的用量以及反应温度和反应时间等条件对所得Ag2S量子点光学性质的影响。在最优条件下制得的Ag_(2)S量子点粒径约4.6 nm,水合直径约为9.3 nm,荧光发射峰在1280 nm左右,荧光量子产率可达2.02%。为了进一步提高所得量子点的生物相容性和血液循环时间,利用主客体相互作用进一步修饰了金刚烷化聚乙二醇(Ad-PEG)分子。负载PEG的Ag_(2)S量子点生物相容性好,在水溶液中具有良好的分散性和稳定性,可用于小鼠全身血管的成像,是一种有潜力的近红外二区荧光探针。

With mono(6-mercapto-6-deoxy)-β-cyclodextrin as stabilizer,cyclodextrin-modified Ag_(2)S quantum dots with strong NIR-Ⅱemission were prepared in aqueous solution.By optimizing the ratio between silver and sulfur,the amount ofβ-cyclodextrin,the reaction temperature and reaction time,Ag_(2)S quantum dots with an emission peak around 1280 nm were obtained.The quantum yield of the optimized sample was around 2.02%.The average size and hydrodynamic diameter of the obtained quantum dots were found to be 4.6 and 9.3 nm respectively.Adamantyl attached polyethylene glycol(Ad-PEG)were further modified to improve the biocompatibility and blood circulation of Ag_(2)S quantum dots through host-guest interactions.The obtained PEGylated Ag_(2)S quantum dots with good biocompatibility,high dispersity and stability,were used for NIR-Ⅱimaging of whole-body blood vessels in living mice,and were promising NIR-Ⅱfluorescent probes.