Gd^(3+)/Yb^(3+)掺杂ZnO量子点作为双模式磁共振/CT成像探针

Gd^(3+)/Yb^(3+)-Doped Zinc Oxide Quantum Dots for Dual Modal Magnetic Resonance Imaging/Computed Tomographic Imaging

基于结合磁共振成像(MRI)的高空间分辨率和CT成像的深穿透能力设计思想,在乙醇溶液中水解醋酸锌、醋酸钆和醋酸镱,制备了油酸稳定的Gd3+/Yb3+掺杂ZnO量子点(ZnO∶Gd/Yb),并对其表面进行了氨基修饰。研究了ZnO∶Gd/Yb量子点的弛豫性能、X射线吸收性能、细胞毒性及体外MRI和CT成像。当Zn2+,Gd3+,Yb3+的摩尔比为1.0∶0.12∶0.20时,ZnO∶Gd/Yb量子点展现了最高的弛豫效率6.06 mmol/(L.s)对X-射线的吸收能力也显著高于临床CT造影剂碘比醇。体外MRI和CT成像实验表明,当Gd3+的浓度为1.5 mmol/L时,T1加权MRI信号明显增强,当Yb3+的浓度为5 g/L时,可呈现清晰的CT图像。细胞毒性实验表明,ZnO∶Gd/Yb量子点的浓度低于1.5 mmol/L(Gd3+)时,量子点的毒性相对较低。

The oleate-stabilized ZnO：Gd/Yb QDs was first prepared by doping rare earth ions into ZnO host matrix in ethanol solution,and then amido was grafted onto the surface by a covalent bond.These nanoprobes,with exceptionally small size and good water-dispersability,exhibited a longitudinal relaxivity r1 of 6.06 mmol/（L·s）,which was higher than that of clinic contrast agent Gd-diethylenetriaminepentaacetic acid（DTPA）（4.3 mmol/（L·s））.In magnetic resonance imaging（MRI） studies,they exerted strong positive contrast effect when the Gd concentration was 1.5 mmol/L.Furthermore,computed tomography（CT） imaging showed that these nanoprobes could induce an efficient contrast enhancement when the Yb concentration was at least equal to 5.0 g/L.These nanoprobes presented relatively low toxicity or adverse affect on cell growth even at the concentration up to 1.5 mmol/L Gd3＋.