title: Synthesis, Characterization,In VitroPhantom Imaging, and Cytotoxicity of A Novel Graphene-Based Multimodal Magnetic Resonance Imaging - X-Ray Computed Tomography Contrast Agent.
abstract: Graphene nanoplatelets (GNPs), synthesized using potassium permanganate-based oxidation and exfoliation followed by reduction with hydroiodic acid (rGNP-HI), have intercalated manganese ions within the graphene sheets, and upon functionalization with iodine, show excellent potential as biomodal contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT). Structural characterization of rGNP-HI nanoparticles with low- and high-resolution transmission electron microscope (TEM) showed disc-shaped nanoparticles (average diameter, 200 nm, average thickness, 3 nm). Energy dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of intercalated manganese. Raman spectroscopy and X-ray diffraction (XRD) analysis of rGNP-HI confirmed the reduction of oxidized GNPs (O-GNPs), absence of molecular and physically adsorbed iodine, and the functionalization of graphene with iodine as polyiodide complexes (I3-and I5-). Manganese and iodine content were quantified as 5.1 ± 0.5 and 10.54 ± 0.87 wt% by inductively-coupled plasma optical emission spectroscopy and ion-selective electrode measurements, respectively.In vitrocytotoxicity analysis, using absorbance (LDH assay) and fluorescence (calcein AM) based assays, performed on NIH3T3 mouse fibroblasts and A498 human kidney epithelial cells, showed CD50values of rGNP-HI between 179-301 µg/ml, depending on the cell line and the cytotoxicity assay. CT and MRI phantom imaging of rGNP-HI showed high CT (approximately 3200% greater than HI at equimolar iodine concentration) and MRI (approximately 59% greater than equimolar Mn2+solution) contrast. These results open avenues for furtherin vivosafety and efficacy studies towards the development of carbon nanostructure-based multimodal MRI-CT contrast agents.
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794-5281.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Lalwani
authors.affiliation: Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794.
authors.forename: Joe Livingston
authors.initials: JL
authors.lastname: Sundararaj
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794-5281.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Schaefer
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794-5281 ; Department of Radiology, Stony Brook University, Stony Brook, New York 11794.
authors.forename: Terry
authors.initials: T
authors.lastname: Button
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794-5281.
authors.forename: Balaji
authors.initials: B
authors.lastname: Sitharaman