Macromolecules with Different Charges, Lengths, and Coordination Groups for the Coprecipitation Synthesis of Magnetic Iron Oxide Nanoparticles as <i>T</i>₁ MRI Contrast Agents

• Main Authors: Cheng Tao, Yanan Chen, Danli Wang, Yu Cai, Qiang Zheng, Lu An, Jiaomin Lin, Qiwei Tian, Shiping Yang
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Nanomaterials
• Subjects: <i>T</i>₁-weight contrasts; iron oxide; surface charge; coprecipitation synthesis; MRI
• Online Access: https://www.mdpi.com/2079-4991/9/5/699
• ISSN: 2079-4991

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe₃O₄ nanoparticles as <i>T</i>₁ magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe₃O₄ nanoparticles through coprecipitation reaction. The obtained Fe₃O₄-PAA, Fe₃O₄-PAH, and Fe₃O₄-PVA nanoparticles showed <i>T</i>₁ contrast performance with <i>r</i>₁ relaxivities of 23.4, 60.3, and 30.6 mM s^&#8722;1 at 0.5 T (25 &#176;C), and a <i>r</i>₂/<i>r</i>₁ ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe₃O₄-PAA and Fe₃O₄-PVA exhibited good biocompatibility, while Fe₃O₄-PAH displayed high cytotoxicity. In vivo <i>T</i>₁-weighted (1 T) mice showed that both Fe₃O₄-PAA and Fe₃O₄-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe₃O₄-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and <i>T</i>₁ contrast performance of magnetic Fe₃O₄ nanoparticles.