以Cy5.5为包裹的团簇磁共振分子探针G4-Gd_(2)O_(3)-Cy5.5的构建与表征

Construction and Characterization of Cy5.5 Surrounded Nanoclusters Magnetic Resonance Molecular Probe G4-Gd_(2)O_(3)-Cy5.5

目的合成花菁素染料Cy5.5团簇磁共振分子探针G4-Gd_(2)O_(3)-Cy5.5,并初步研究其粒径、稳定性及MRI表现。方法在G4-COOH(PAMAM)树状大分子溶液中,添加GdCl3并用NaOH溶液碱化后,透析冷冻干燥得到G4-Gd_(2)O_(3)纳米颗粒。再进一步偶联花菁素染料荧光素Cy5.5,后得到G4-Gd_(2)O_(3)-Cy5.5。之后用透射电镜(TEM)检测其粒径,动态光散射法检测其水动力尺寸和zeta电位。运用3.0 T MRI观察其MR显像效果,并利用ICP-MS数据线性拟合测算分子探针的弛豫率。结果G4-Gd_(2)O_(3)-Cy5.5制备成功,测得其的水动力尺寸为(48.0±8.9)nm,zeta电位为(-39.8±2.9)mV;TEM测得纳米颗粒粒径为(48.0±8.9)nm,透射电镜扫描模式(STEM)测得粒径为(49.0±2.9)nm;随着G4-Gd_(2)O_(3)-Cy5.5的浓度逐步升高,T_(1)信号强度逐渐增强,T_(2)信号强度无明显变化,经线性拟合得到横向弛豫率(r_(1))为49.6 s^(-1)·mM^(-1)。结论以Cy5.5为包裹的团簇磁共振分子探针G4-Gd_(2)O_(3)-Cy5.5具有一定的分散性和良好的稳定性,并且可以显著升高T_(1)信号弛豫率。

Objective Synthesis of Cyanine dye Cy5.5 cluster nanoclusters MR molecular probe G4-Gd_(2)O_(3)-Cy5.5,and preliminarily study its particle size,stability and MR expression.Methods In G4-COOH(PAMAM)dendrimer solution,GdCl3 was added and alkalized with NaOH solution,then G4-Gd_(2)O_(3)nanoparticles were obtained by dialysis and freeze drying.Then further coupled with the Cyanine dye cy5.5,G4-Gd_(2)O_(3)-Cy5.5 was obtained.After that,its particle size was detected by TEM and its hydrodynamic size and zeta potential were detected by dynamic light scattering.The MR imaging effect was observed by 3.0 T MRI,and the relaxation rate of the molecular probe was calculated using ICP-MS data.Results G4-Gd_(2)O_(3)-Cy5.5 was successfully prepared and measured to have a hydrodynamic size of(48.0±8.9)nm and zeta potential of(-39.8±2.9)mV;The particle size of nanoparticles was(48±8.9)nm by transmission electron microscopy(TEM),and the particle size of STEM was(49±2.9)nm;With the gradual increase of G4-Gd_(2)O_(3)-Cy5.5 concentration,the T_(1)signal intensity gradually increased,and the T_(2)signal intensity did not change significantly.The transverse relaxation rate of R_(1)was 49.6 s^(-1)mM^(-1)by linear fitting.Conclusion The cyanine dye cy5.5 cluster nanoclusters MR molecular probe G4-Gd_(2)O_(3)-Cy5.5 has a certain dispersion and good stability,and can significantly increase the relaxation rate of T_(1)signal.