title: Gadolinium oxide nanoplates with high longitudinal relaxivity for magnetic resonance imaging.
abstract: Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)(-1) were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values moderately reduce as the size of the Gd2O3 nanoplates increases, and are always larger for the PAA-OA coating. Cytotoxicity studies on human dermal fibroblast cells documented no significant toxicity, with 100% cell viability preserved up to 250 μM for the PAA-OA coated Gd2O3 nanoplates. Given the 10 times increase in longitudinal relaxivity over the commercially available Gd-based molecular agents and the favorable toxicity profile, the 2 nm PAA-OA coated Gd2O3 nanoplates could represent a new class of highly effective T1 MRI contrast agents.
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA. colvin@rice.edu colvin.vicki@gmail.com.
authors.forename: Minjung
authors.initials: M
authors.lastname: Cho
authors.forename: Richa
authors.initials: R
authors.lastname: Sethi
authors.forename: Jeyarama Subramanian Ananta
authors.initials: JS
authors.lastname: Narayanan
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Denise N
authors.initials: DN
authors.lastname: Benoit
authors.forename: Nasim
authors.initials: N
authors.lastname: Taheri
authors.forename: Paolo
authors.initials: P
authors.lastname: Decuzzi
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Colvin
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000493:pharmacokinetics; D003287:Contrast Media / Q000737:chemistry / Q000493:pharmacokinetics; D004337:Drug Carriers / Q000737:chemistry / Q000493:pharmacokinetics; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005682:Gadolinium / Q000737:chemistry* / Q000493:pharmacokinetics*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000493:pharmacokinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry; D019301:Oleic Acid / Q000737:chemistry; D013997:Time Factors
chemical_list: D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D004337:Drug Carriers; D008051:Lipid Bilayers; D019301:Oleic Acid; C030581:gadolinium oxide; D005682:Gadolinium