Contrast Agent in Magnetic Resonance Imaging

Research output: Book/anthology/dissertation/reportPh.D. thesisResearch

  • Hieu Vu-Quang, Denmark
Nanoparticles have been employed as contrast agent in magnetic resonance imaging (MRI) in order to improve sensitivity and accuracy in diagnosis. In addition, these contrast agents are potentially combined with other therapeutic compounds or near infrared bio-imaging (NIR) fluorophores to obtain theranostic or dual imaging purposes, respectively. There were two main types of MRI contrast agent that were synthesized during this PhD project including fluorine containing nanoparticles and magnetic nanoparticles.
In regard of fluorine containing nanoparticles, there were two types contrast agent that were synthesized in project I and II. In project I, Poly (lactic-co-glycolic acid)-block-poly (ethylene glycol)-Folate Pefluorooctyl Bromide/Indocyanine green/ Doxorubicin (PLGA-PEG-Folate PFOB/ICG/Dox) has been formulated for the dual imaging NIR and 19F MRI as well as in the combination of Dox for chemotherapy. The nanoparticles were 150 nm in size with spherical shape, which contained PFOB in the inner core and Dox and ICG in the polymeric shell. More importantly, they could target folate receptor expressing cancer cells, which provide positive in vitro and in vivo NIR and 19F MRI results. In project II, F127 coated PLGA PFOB and chitosan coated PLGA PFOB nanoparticles were synthesized for cell labeling. Coating chitosan or F127 onto PLGA-PFOB nanoparticles increased their size and zeta potential. The highest labeling efficiency yielding 19F MR images, which was achieved for human mesenchymal stem cells and Raw 264.7 macrophages were chitosan-to-particles weight ratios of w0.1 and w0.01, respectively. In vivo 19F MRI results showed the possibility of capturing labeled cells indicating the potential use of PLGA PFOB in future research involving such as cell migration. .
In regard of magnetic nanoparticles, there were two types of particles that were synthesized in project III and IV. In project III, it was aimed to understand the role of macrophage in inflammation, which is vital information for treatment purpose. In this project, the siRNA/bPEI coated PLGA SPION/ICG nanoparticles have been formulated in order to suppress inflamed cytokine expression by siRNA transfection as well as following the migration of macrophage using MRI and NIR bio-imaging. The nano-complexes could inhibit 50 % mRNA expression and 39 % protein expression. In the in vivo cell tracking NIR bio-imaging and MRI, nanoparticles showed the possibility of locating and following the migration of macrophage from the peritoneal to unilateral ureter obstruction kidney six hours after administration. Project IV was aimed to develop the F127-Folate coated SPION, which could effectively target to folate receptors expression cancer cells for cancer diagnosis in MRI. F127-Folate coated SPION were stable in various types of suspension medium for over six months. They could specifically target folate receptor of cancer cells in vitro and in vivo thus enhancing the contrast in MRI T2/T2* weighted images. These are preliminary results, which require further research for a complete understanding.
Original languageEnglish
Number of pages212
Publication statusPublished - 2015

    Research areas

  • PLGA , PFOB, MRI, 19F MRI, SPION, F127, Chitosan, PEI, siRNA, NIR, Nanoparticles, Cancer, Inflammation, ICG

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