Gd/Y Hydroxide Nanosheets as Highly Efficient T1/T2 MRI Contrast Agents.

Xin Li,Guohong Zhou,Zhenhai Xue,Qiang Li,Cuiyan Yu,Danyu Jiang,Jinfeng Xia,Jiayan Miu,Yuerong Heng,Wenhui Wang,Mengting Dai

doi:10.3390/nano11010017

Abstract

To develop highly efficient T1/T2 magnetic resonance imaging (MRI) contrast agents (CAs), Gd/Y hydroxide nanosheets were synthesized by a simple exfoliation method from layer compounds using sodium polyacrylate (PAA) as a dispersant and stabilizer. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) results revealed the excellent performance of monolayer nanosheets with thicknesses of up to 1.5 nm. The MRI results of the T1 and T2 relaxation times showed that all of the Gd/Y hydroxide nanosheets have high longitudinal and transverse relaxivities (r1 and r2). In particular, the 10% Gd-LRH nanosheets exhibited excellent MRI performance (r1 = 103 mM−1 s−1, r2 = 372 mM−1 s−1), which is rarely reported. Based on the relationship between the structure of 10% Gd-LRH nanosheets and their MRI performances, and the highly efficient MRI of spaced Gd atoms in the nanosheets, a special model to explain the outstanding MRI performance of the 10% Gd-LRH nanosheets is suggested. The cytotoxicity assessment of the 10% Gd-LRH nanosheets, evaluated by CCK-8 assays on HeLa cells, indicated no significant cytotoxicity. This study presents a significant advancement in 2D nanomaterial MRI CA research, with Gd-doped nanosheets positioned as highly efficient T1/T2 MRI CA candidates.

Highlights

As a solution to Gd leakage from Gd (III) chelates and nephrogenic systemic fibrosis (NSF) [1,2], scientists have focused on synthesizing harmless contrast agents (CAs) with high relaxivity and excellent stability at a low dose
Most dual-mode T1 and T2 magnetic resonance imaging (MRI) CAs have been designed as NPs with Gd shells [5,6,7,8]; in this study we propose a special 2D-structured Gd compound with remarkable T1 and T2 imaging functions
CAs than many reported NP CAs, and they significantly exceeded the results previously reported for Layered rare-earth hydroxides (LRHs) suspensions (r1 even greater than 100 mM−1 s−1 )

Summary

Introduction

As a solution to Gd leakage from Gd (III) chelates and nephrogenic systemic fibrosis (NSF) [1,2], scientists have focused on synthesizing harmless contrast agents (CAs) with high relaxivity and excellent stability at a low dose. Several kinds of nanostructured magnetic resonance imaging (MRI) CAs have been developed. Gd3+ ions bound on the surface of nanoparticles (NPs) play a major role in accelerating relaxation, whereas the contribution from inner Gd3+ ions could be neglected [3]. To further reduce the consumption of Gd, monolayer Gd nanosheets are the best alternatives to CAs. Theoretically, Gd compounds can be good dual-modal CAs. Research has shown that CAs with Gd as the magnetic center exhibit excellent T1 /T2 dual-mode imaging possibilities [4]. Most dual-mode T1 and T2 MRI CAs have been designed as NPs with Gd shells [5,6,7,8]; in this study we propose a special 2D-structured Gd compound with remarkable T1 and T2 imaging functions

Methods

Results

Discussion

Conclusion