The properties of Gd2O3-assembled silica nanocomposite targeted nanoprobes and their application in MRI

The feasibility of the gadolinium-doped mesoporous silica nanocomposite Gd2O3@MCM-41 as a safe, effective MRI nanoprobe has been validated in the current investigation systematically from atomistic and molecular modeling to its synthesis and characterization on in vivo MR imaging and biocompatibility. The first-principles calculation indicates that it is nearly impossible for toxic Gd ions to dissociate freely from silica. The biocompatibility studies confirm that the nanocomposite is lack of any potential toxicity: the biodistribution studies reveal a greater accumulation of the nanocomposite in liver, spleen, lung and tumor than in kidney, heart and brain; the excretion studies show that the nanocomposite can be cleared nearly 50% via the hepatobiliary transport mechanism after 1.5 months of injection. A larger water proton relaxivity r(1) and a better T-1-weighted phantom MR imaging capability were detected in the nanocomposite than in the commercially available gadolinium diethylenetriaminepentaacetate. The results demonstrate that the nanocomposite is superior to the commercial counterpart in terms of contrast enhancement with a satisfactory biocompatibility, and it has a high potential to be developed into a safe and effective targeted probe for in vivo molecular imaging of cancer. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.

在当前的研究中，从原子和分子建模到其合成以及体内磁共振成像和生物相容性的表征，系统地验证了钆掺杂介孔二氧化硅纳米复合材料Gd₂O₃@MCM - 41作为一种安全、有效的磁共振成像纳米探针的可行性。第一性原理计算表明，有毒的钆离子几乎不可能从二氧化硅中自由解离。生物相容性研究证实该纳米复合材料没有任何潜在毒性：生物分布研究显示，该纳米复合材料在肝脏、脾脏、肺和肿瘤中的蓄积量比在肾脏、心脏和大脑中更多；排泄研究表明，注射1.5个月后，该纳米复合材料可通过肝胆转运机制清除近50%。与市售的二乙三胺五乙酸钆相比，该纳米复合材料检测到更大的水质子弛豫率r(1)和更好的T - 1加权体模磁共振成像能力。结果表明，该纳米复合材料在对比度增强方面优于市售产品，且具有令人满意的生物相容性，它极有可能被开发成为一种用于癌症体内分子成像的安全有效的靶向探针。版权所有（c）2012，由爱思唯尔有限公司出版。保留所有权利。