title: Gd-Al co-doped mesoporous silica nanoparticles loaded with Ru(bpy)₃²⁺ as a dual-modality probe for fluorescence and magnetic resonance imaging.
abstract: Mesoporous silica nanoparticles (MSNs) were co-doped with Gd(3+) and Al(3+) and then loaded with Ru(bpy)3(2+) by ion-exchange to prepare Ru/Gd-Al@MSNs. The as-prepared Ru/Gd-Al@MSNs were applied as contrast agents for in vivo fluorescence and magnetic resonance (MR) dual-modality imaging with a mouse as a model. The effects of Al(3+) and MSNs on longitudinal relaxivity (r1) and fluorescence were investigated using a series of Gd-containing silica nanoparticles, including Gd@MSNs, Gd-Al@MSNs, and Ru/Gd-Al@nonporous silica nanoparticles. Co-doping with Al(3+) improved the loading of Gd(3+); the mesoporous structure improved the water exchange rate. The improvement enhanced the MR imaging efficiency of the Ru/Gd-Al@MSN probe. A higher relaxivity (19.2 mM(-1) s(-1)) was observed compared to that from a commercial contrast agent, Gd-diethylene triamine pentaacetic acid (Gd-DTPA). Importantly, the mesoporous structure provided a large specific surface area for the loading of Ru(bpy)3(2+) by a simple ion-exchange procedure. Intense red fluorescence was observed from Ru/Gd-Al@MSN probes. The versatility of Ru/Gd-Al@MSNs for dual-modality imaging was demonstrated using in vivo fluorescence imaging and T1-weighted MR imaging with a mouse model. The nanoparticles are biocompatible and may be attractive for clinical applications.
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), and Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, 300071, China. xbyin@nankai.edu.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Ai
authors.initials: A
authors.lastname: Gao
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.forename: Xue-Bo
authors.initials: XB
authors.lastname: Yin
authors.forename: Xi-Wen
authors.initials: XW
authors.lastname: He
authors.forename: Yu-Kui
authors.initials: YK
authors.lastname: Zhang
mesh_terms: D015082:2,2'-Dipyridyl / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D000535:Aluminum / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D056831:Coordination Complexes; D005260:Female; D005456:Fluorescent Dyes / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005682:Gadolinium / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000493:pharmacokinetics; D056945:Hep G2 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D061848:Optical Imaging; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D017975:Ruthenium Compounds
chemical_list: D015082:2,2'-Dipyridyl; D000535:Aluminum; D003287:Contrast Media; D056831:Coordination Complexes; D005456:Fluorescent Dyes; D005682:Gadolinium; D019786:Gadolinium DTPA; D012822:Silicon Dioxide; C547232:tris(2,2-bipyridine)-ruthenium(II); D017975:Ruthenium Compounds