title: Development of nanoparticle-based magnetic resonance colonography.
abstract: This study was to develop a novel method of nanoparticle-based MR colonography. Two types of solid lipid nanoparticles (SLNs) were synthesized with loading of (a) gadolinium (Gd) diethylenetriaminepenta acetic acid to construct Gd-SLNs as an MR T1 contrast agent and (b) otcadecylamine-fluorescein-isothiocyanate to construct Gd-fluorescein isothiocyanate (FITC)-SLNs for histologic confirmation of MR findings. Through an in vitro experiment, we first evaluated the size distribution and gadolinium diethylenetriaminepenta acetic acid entrapment efficiency of these SLNs. The SLNs displayed a size distribution of 50-300 nm and a gadolinium diethylenetriaminepenta acetic acid entrapment efficiency of 56%. For in vivo validation, 30 mice were divided into five groups, each of which was administered a transrectal enema using: (i) Gd-SLNs (n=6); (ii) Gd-FITC-SLNs (n=6); (iii) blank SLNs (n=6); (iv) gadolinium diethylenetriaminepenta acetic acid (n=6); and (v) water (n=6). T1-weighted fluid-attenuated inversion-recovery MRI was then performed on mice after transrectal infusion of Gd-SLNs or Gd-FITC-SLNs, which demonstrated bright enhancement of the colonic walls, with decrease in T1 relaxation time. When Gd-FITC-SLNs were delivered, green fluorescent spots were visualized in both the extracelluar space and the cytoplasm through colonic walls under confocal microscopy and fluorescence microscopy. This study establishes the "proof-of-principle" of a new imaging technique, called "nanoparticle-based MR colonography," which may provide a useful imaging tool for the diagnosis of colorectal diseases.
authors.affiliation: Department of Radiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, China.
authors.forename: Jihong
authors.initials: J
authors.lastname: Sun
authors.forename: Weiliang
authors.initials: W
authors.lastname: Zheng
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Hong
authors.initials: H
authors.lastname: Yuan
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
authors.forename: Shizheng
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003106:Colon / Q000033:anatomy & histology*; D019786:Gadolinium DTPA / Q000138:chemical synthesis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008954:Models, Biological; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D019786:Gadolinium DTPA