title: Manganese ferrite nanoparticle micellar nanocomposites as MRI contrast agent for liver imaging.
abstract: Iron oxide nanoparticles are effective contrast agents for enhancement of magnetic resonance imaging at tissue, cellular or even molecular levels. In this study, manganese doped superparamagnetic iron oxide (Mn-SPIO) nanoparticles were used to form ultrasensitive MRI contrast agents for liver imaging. Hydrophobic Mn-SPIO nanoparticles are synthesized in organic phase and then transferred into water with the help of block copolymer mPEG-b-PCL. These Mn-SPIO nanoparticles are self-assembled into small clusters (mean diameter approximately 80nm) inside micelles as revealed by transmission electron microscopy. Mn-SPIO nanoparticles inside micelles decrease PCL crystallization temperatures, as verified from differential scanning calorimetry and Fourier transform infrared spectroscopy. The Mn-SPIO based nanocomposites are superparamagnetic at room temperature. At the magnetic field of 1.5T, Mn-SPIO nanoparticle clustering micelles have a T(2) relaxivity of 270 (Mn+Fe)mM(-1)s(-1), which is much higher than single Mn-SPIO nanoparticle containing lipid-PEG micelles. This clustered nanocomposite has brought significant liver contrast with signal intensity changes of -80% at 5min after intravenous administration. The time window for enhanced-MRI can last about 36h with obvious contrast on liver images. This sensitive MRI contrast agent may find applications in identification of small liver lesions, evaluation of the degree of liver cirrhosis, and differential diagnosis of other liver diseases.
authors.affiliation: National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Shuli
authors.initials: S
authors.lastname: Ma
authors.forename: Jiayu
authors.initials: J
authors.lastname: Sun
authors.forename: Chunchao
authors.initials: C
authors.lastname: Xia
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
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; D002152:Calorimetry, Differential Scanning; D045744:Cell Line, Tumor; D003287:Contrast Media; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008345:Manganese / Q000737:chemistry*; D053768:Metal Nanoparticles; D051379:Mice; D008823:Micelles; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D008823:Micelles; C001215:ferrite; D008345:Manganese