title: Noninvasive MRI-SERS imaging in living mice using an innately bimodal nanomaterial.
abstract: We report a novel nanomaterial (AuMN-DTTC) that can be used as a bimodal contrast agent for in vivo magnetic resonance imaging (MRI) and Raman spectroscopy. The probe consists of MRI-active superparamagnetic iron oxide nanoparticles, stably complexed with gold nanostructures. The gold component serves as a substrate for a Raman active dye molecule to generate a surface-enhanced Raman scattering (SERS) effect. The synthesized probe produces T2 weighted contrast and can be used as a SERS active material both in silico (in aqueous solution) and in vivo. A quantitative assessment of T2 relaxation times was obtained using multiecho MRI analysis. The T2 relaxation times of AuMN-DTTC and MN (dextran-coated iron oxide nanoparticles) were 29.23 + 1.45 and 31.58 + 1.7 ms, respectively. The SERS signature of AuMN-DTTC revealed peaks at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm(-1). Intramuscular administration of the probe resulted in a decrease of the T2 relaxation time of muscle from 33.4 + 2.5 to 20.3 + 2.2 ms. SERS peaks were observed at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm(-1), consistent with the in silico results. Our studies illustrate for the first time the design and in vivo application of a contrast agent, whose component modalities include MRI and SERS. The value of this agent lies in its innately bimodal nature and its application in vivo for molecular imaging applications.
authors.affiliation: Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Mehmet V
authors.initials: MV
authors.lastname: Yigit
authors.forename: Leyun
authors.initials: L
authors.lastname: Zhu
authors.forename: Marytheresa A
authors.initials: MA
authors.lastname: Ifediba
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kevin
authors.initials: K
authors.lastname: Carr
authors.forename: Anna
authors.initials: A
authors.lastname: Moore
authors.forename: Zdravka
authors.initials: Z
authors.lastname: Medarova
mesh_terms: D000818:Animals; D002417:Cattle; D003287:Contrast Media; D003911:Dextrans / Q000737:chemistry; D004355:Drug Stability; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D049329:Nanostructures / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D003287:Contrast Media; D003911:Dextrans; D005290:Ferric Compounds; D012492:Salts; C000499:ferric oxide; D006046:Gold