A design strategy of ultrasmall Gd 2 O 3 nanoparticles for T 1 MRI with high performance

• Published in: New journal of chemistry Vol. 45; no. 16; pp. 7270 - 7277
• Main Authors: Yang, Jianfeng, Shan, Pengyuan, Zhao, Qingling, Zhang, Shuquan, Li, Lanlan, Yang, Xiaojing, Yu, Xiaofei, Lu, Zunming, Wang, Ziwu, Zhang, Xinghua
• Format: Journal Article
• Language: English
• Published: 26.04.2021
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/D1NJ00508A

It is still a big challenge to design Gd 3+ based nanoparticles (NPs) for T 1 MRI (Magnetic Resonance Imaging) with high performance and clarify the effects of relative time parameters on longitudinal relaxivity r 1 . In this paper, we simulated the influences of different time parameters on the longitudinal relaxivity of Gd 3+ based NPs with inner-sphere and outer-sphere theories, respectively. In particular, we investigated the effects of τ R (the rotational time), τ M (the residence time), T ie (the electronic relation time) and τ d (the diffusion time) on longitudinal relaxivity. In the relaxation process of Gd 3+ based NPs, the inner-sphere plays a dominant role, in which τ R and τ M have a greater impact on r 1 . Based on the simulation results, we proposed a design strategy of Gd 3+ based NPs for T 1 MRI, which focuses on the rational decrease of hydrated radius, and the optimal range of the hydrated radius is about 0.8–2.5 nm. In addition, we synthesized ultrasmall Gd 2 O 3 NPs with a hydrated radius of about 2.5 nm, which have a high longitudinal relaxivity r 1 of 10.8 mM −1 s −1 at 3.0 T. Moreover, the in vivo imaging results confirm that the ultrasmall Gd 2 O 3 NPs have a good imaging effect on the tumor, and it can be a good candidate as a T 1 MRI contrast agent with high performance.