Engineered Paramagnetic Graphene Quantum Dots with Enhanced Relaxivity for Tumor Imaging
Engineered Paramagnetic Graphene Quantum Dots with Enhanced Relaxivity for Tumor Imaging
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用于肿瘤成像的具有增强弛豫性的工程顺磁石墨烯量子点
DOI：
10.1021/acs.nanolett.8b04252
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发表时间：
2019
期刊：
影响因子：
10.8
通讯作者：
Zhou Xin
中科院分区：
文献类型：
--
作者：
Yang Yuqi;Chen Shizhen;Li Haidong;Yuan Yaping;Zhang Zhiying;Xie Junshuai;Hwang Dennis W.;Zhang Aidong;Liu Maili;Zhou Xin
纳米造影剂（Nano CA）是一种在医学磁共振成像（MRI）中用于增强对比度的纳米材料。然而，纳米CA的相关弛豫机制尚不清楚，在弛豫增强方面也没有取得重大突破。本文合成了一种具有不同链长的聚乙二醇功能化的新型亲水性Gd-DOTA配合物，并将其掺入石墨烯量子点（GQD）中，得到顺磁性石墨烯量子点（PGQD）。我们对三种不同链长的PGQD在水溶液中的水交换和旋转动力学进行了变温度变场强核磁共振研究。顺磁链长度的最佳GQD在1h NMR弛豫研究中表现出很大的性能改善。体外实验结果表明，设计的PGQD的弛豫度可以通过调节PEG长度来控制，并且以“每Gd”为基础，其弛豫度比当前商用MRI造影剂（例如Gd- dtpa）的弛豫度高~ 16倍。纳米CA的弛豫度可以合理调整，从而在MR成像中获得不匹配的电位，例如制备了具有增强弛豫度的顺磁性GQD。所制备的PEG长度合适的PGQDs在1.5 T时弛豫最佳，经静脉注射后，其被实体瘤摄食的过程甚至可以通过临床使用的1.5 T MRI扫描仪监测。本研究也将为高效磁共振造影剂的设计和合成提供一个良好的平台。
Nano contrast agents (Nano CA) are nanomaterials used to increase contrast in the medical magnetic resonance imaging (MRI). However, the related relaxation mechanism of the Nano CA is not clear yet and little significant breakthrough in relaxivity enhancement has been achieved. Herein, a new hydrophilic Gd-DOTA complex functionalized with different chain length of PEG was synthesized and incorporated into graphene quantum dots (GQD) to obtain paramagnetic graphene quantum dots (PGQD). We performed a variable-temperature and variable-field intensity NMR study in aqueous solution on the water exchange and rotational dynamics of three different chain lengths of PGQD. The optimal GQD with paramagnetic chain length shows a great improvement in performance on1H NMR relaxometric studies.In vitroresults demonstrated that the relaxivity of the designed PGQD could be controlled by regulating the PEG length, and its relaxivity was ∼16 times higher than that of current commercial MRI contrast agents (e.g., Gd-DTPA), on a “per Gd” basis. The relaxivity of the Nano CA can be rationally tuned to obtain unmatched potentials in MR imaging, exemplified by preparation of the paramagnetic GQD with the enhancedT1relaxivity. The fabricated PGQDs with suitable PEG length got the best relaxivity at 1.5 T. After intravenous injection, its feeding process by solid tumor could even be monitored by clinically used 1.5 T MRI scanners. This research will also provide an excellent platform for the design and synthesis of highly effective MR contrast agents.