Ligand-size and ligand-chain hydrophilicity effects on the relaxometric properties of ultrasmall Gd2O3 nanoparticles
Tirusew Tegafaw,
Wenlong Xu,
Sang Hyup Lee,
Kwon Seok Chae,
Hyunsil Cha,
Yongmin Chang,
Gang Ho Lee
Affiliations
Tirusew Tegafaw
Department of Chemistry and Department of Nanoscience and Nanotechnology (DNN), College of Natural Sciences, Kyungpook National University (KNU), Taegu 41566, South Korea
Wenlong Xu
Department of Chemistry and Department of Nanoscience and Nanotechnology (DNN), College of Natural Sciences, Kyungpook National University (KNU), Taegu 41566, South Korea
Sang Hyup Lee
Department of Biology Education and DNN, Teacher’s College, KNU, Taegu 41566, South Korea
Kwon Seok Chae
Department of Biology Education and DNN, Teacher’s College, KNU, Taegu 41566, South Korea
Hyunsil Cha
Department of Molecular Medicine and Medical & Biological Engineering and DNN, School of Medicine and Hospital, KNU, Taegu 41566, South Korea
Yongmin Chang
Department of Molecular Medicine and Medical & Biological Engineering and DNN, School of Medicine and Hospital, KNU, Taegu 41566, South Korea
Gang Ho Lee
Department of Chemistry and Department of Nanoscience and Nanotechnology (DNN), College of Natural Sciences, Kyungpook National University (KNU), Taegu 41566, South Korea
The relaxometric properties of ultrasmall Gd2O3 nanoparticles coated with various ligands were investigated. These ligands include small diacids with hydrophobic chains, namely, succinic acid (Mw = 118.09 amu), glutaric acid (Mw = 132.12 amu), and terephthalic acid (Mw = 166.13 amu), and large polyethylenimines (PEIs) with hydrophilic chains, namely, PEI-1300 ( M ¯ n = 1300 ) and PEI-10000 ( M ¯ n = 10000 ). Ligand-size and ligand-chain hydrophilicity effects were observed. The longitudinal (r1) and transverse (r2) water proton relaxivities generally decreased with increasing ligand-size (the ligand-size effect). The ligand-size effect was weaker for PEI because its hydrophilic chains allow water molecules to access the nanoparticle (the ligand-chain hydrophilicity effect). This result was explained on the basis of the magnetic dipole interaction between the dipoles of the nanoparticle and water proton. In addition, all samples were found to be non-toxic in cellular cytotoxicity tests.
