Polyaspartic Acid-Coated Paramagnetic Gadolinium Oxide Nanoparticles as a Dual-Modal T1 and T2 Magnetic Resonance Imaging Contrast Agent

Shanti Marasini,Abdullah Khamis Ali Al Saidi,Kwon-Seok Chae,Tirusew Tegafaw,Huan Yue,Mohammad Yaseen Ahmad,Gang Ho Lee,Dejun Zhao,Hyunsil Cha,Adibehalsadat Ghazanfari,Ying Liu,Son Long Ho,Yongmin Chang,Ji Ae Park,Soyeon Kim,Shuwen Liu

doi:10.3390/app11178222

Abstract

Surface-coating polymers contribute to nanoparticle-based magnetic resonance imaging (MRI) contrast agents because they can affect the relaxometric properties of the nanoparticles. In this study, polyaspartic acid (PASA)-coated ultrasmall Gd2O3 nanoparticles with an average particle diameter of 2.0 nm were synthesized using the one-pot polyol method. The synthesized nanoparticles exhibited r1 and r2 of 19.1 and = 53.7 s−1mM−1, respectively, (r1 and r2 are longitudinal and transverse water–proton spin relaxivities, respectively) at 3.0 T MR field, approximately 5 and 10 times higher than those of commercial Gd-chelate contrast agents, respectively. The T1 and T2 MR images could be obtained due to an appreciable r2/r1 ratio of 2.80, indicating their potential as a dual-modal T1 and T2 MRI contrast agent.

Highlights

Biocompatible magnetic nanoparticles have drawn attention owing to their potential applications in biomedical theragnosis [1,2,3,4]
polyaspartic acid (PASA)-coated Gd2 O3 nanoparticles were synthesized through a polyol method (Figure 1)
The average hydrodynamic diameter of the nanoparticles dispersed in triple-distilled water (0.01 mM Gd) was estimated to be 12.7 nm by fitting an observed dynamic light scattering (DLS) pattern to a log-normal function

Summary

Introduction

Biocompatible magnetic nanoparticles have drawn attention owing to their potential applications in biomedical theragnosis [1,2,3,4]. The clinically available Gd-chelates act as positive (or T1 ) MRI contrast agents due to their efficient induction of longitudinal (or T1 ) water–proton spin relaxation with respect to transverse (or T2 ) water–proton spin relaxation, providing r2 /r1 ratios (r1 and r2 are longitudinal and transverse water–proton spin relaxivities, respectively), which are close to one [5,6]. This is due to a high pure spin magnetic moment (S = 7/2) of Gd3+ [5]. The r1 values and as a result, imaging performance can be improved using ultrasmall Gd2 O3 nanoparticles because of their high

Methods

Results

Discussion

Conclusion