title: Self-assembly of SiO2/Gd-DTPA-polyethylenimine nanocomposites as magnetic resonance imaging probes.
abstract: Controlled self-assembly of organic/inorganic magnetic hybrid materials have important applications in magnetic resonance imaging (MRI). In this study, a widely used polycation polyethylenimine was conjugated with gadopentetic acid (Gd-DTPA) as a gadolinium bearing polyelectrolyte (Gd-DTPA-PEI). Next, multilayers of Gd-DTPA-PEI were coated on silica nanoparticles through layer-by-layer (LbL) self-assembly with polyanions as monitored by dynamic light scattering, zeta-potential, and scanning electron microscopy. The thickness of the multilayer film was estimated from quartz crystal microbalance based on counting frequency change of each adsorbed layer. The magnetic relaxation of SiO2/(Gd-DTPA-PEl/polyanion), core-shell nanocomposite was tested at 1.5 T magnetic field in a clinical MRI scanner, and a 3-fold increase in T1 relaxivity to 15.1 Gd mM(-1)s(-1) was noticed comparing to Gd-DTPA small molecules. Dextran sulfate was coated as the outermost layer on the nanocomposite for better biocompatibility as verified by in vitro cytotoxicity studies. This formulation provides good signal intensity enhancement of mouse liver in vivo with only 1/25 dose of clinical standard at 30 and 60 minutes after intravenous injection. This sensitive imaging probe with unique core-shell structures may find broad applications in cellular and molecular imaging.
authors.affiliation: National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Luo
authors.forename: Jing
authors.initials: J
authors.lastname: Tian
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Jiayu
authors.initials: J
authors.lastname: Sun
authors.forename: Chunchao
authors.initials: C
authors.lastname: Xia
authors.forename: Hehan
authors.initials: H
authors.lastname: Tang
authors.forename: Ling
authors.initials: L
authors.lastname: Lin
authors.forename: Tianxin
authors.initials: T
authors.lastname: Miao
authors.forename: Xuna
authors.initials: X
authors.lastname: Zhao
authors.forename: Fabao
authors.initials: F
authors.lastname: Gao
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.forename: Bin
authors.initials: B
authors.lastname: Song
authors.forename: Xintao
authors.initials: X
authors.lastname: Shuai
authors.forename: Hua
authors.initials: H
authors.lastname: Ai
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Gu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival; D019786:Gadolinium DTPA / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007097:Imines / Q000737:chemistry* / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008422:Materials Testing; D051379:Mice; D053761:Nanocomposites / Q000008:administration & dosage / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D000071228:Polyelectrolytes; D011095:Polyethylenes / Q000737:chemistry* / Q000494:pharmacology; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology; D012822:Silicon Dioxide / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D001672:Biocompatible Materials; D019786:Gadolinium DTPA; D007097:Imines; D000071228:Polyelectrolytes; D011095:Polyethylenes; D011108:Polymers; D012822:Silicon Dioxide; C505405:poly(ethylene imine)