Browsing by Author "Law, Justin J."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Encapsulation of α-Particle–Emitting225Ac3+ Ions Within Carbon Nanotubes
    (Society of Nuclear Medicine and Molecular Imaging, 2015) Matson, Michael L.; Villa, Carlos H.; Ananta, Jeyarama S.; Law, Justin J.; Scheinberg, David A.; Wilson, Lon J.; Smalley Institute for Nanoscale Science and Technology
    225Ac3+ is a generator of α-particle–emitting radionuclides with 4 net α-particle decays that can be used therapeutically. Targeting 225Ac3+ by use of ligands conjugated to traditional bifunctional chelates limits the amount of 225Ac3+ that can be delivered. Ultrashort, single-walled carbon nanotubes (US-tubes), previously demonstrated as sequestering agents of trivalent lanthanide ions and small molecules, also successfully incorporate 225Ac3+. Methods: Aqueous loading of both 225Ac3+ ions and Gd3+ ions via bath sonication was used to construct 225Ac@gadonanotubes (225Ac@GNTs). The 225Ac@GNTs were subsequently challenged with heat, time, and human serum. Results: US-tubes internally loaded with both 225Ac3+ ions and Gd3+ ions show 2 distinct populations of 225Ac3+ ions: one rapidly lost in human serum and one that remains bound to the US-tubes despite additional challenge with heat, time, and serum. The presence of the latter population depended on cosequestration of Gd3+ and 225Ac3+ ions. Conclusion: US-tubes successfully sequester 225Ac3+ ions in the presence of Gd3+ ions and retain them after a human serum challenge, rendering 225Ac@GNTs candidates for radioimmunotherapy for delivery of 225Ac3+ ions at higher concentrations than is currently possible for traditional ligand carriers.
  • Thumbnail Image
    Item
    Relaxivity Enhancement of Aquated Tris(β-diketonate)gadolinium(III) Chelates by Confinement within Ultrashort Single-walled Carbon Nanotubes
    (John Wiley & Sons, Inc., 2014) Law, Justin J.; Guven, Adem; Wilson, Lon J.; Richard E. Smalley Institute for Nanoscale Science and Technology
    Ultrashort single-walled carbon nanotubes loaded with gadolinium ions (gadonanotubes) have been previously shown to exhibit extremely high T1-weighted relaxivities (>100 mM-1s-1). To further examine the effect of nanoconfinement on the relaxivity of gadolinium based contrast agents for magnetic resonance imaging (MRI), a series of ultrashort single-walled carbon nanotube (US-tube) materials internally loaded with gadolinium chelates has been prepared and studied. US-tubes were loaded with Gd(acac)3ﾷ2H2O, Gd(hfac)3ﾷ2H2O, and Gd(thd)3. (acac = acetylacetone, hfac = hexafluoroacetylacetone, thd = tetramethylheptanedione) The longitudinal relaxivities of the prepared materials determined at 25ﾰC in a 1.5 T field were 103 mM-1s-1 for Gd(acac)3ﾷ2H2O@US-tubes, 105 mM-1s-1 for Gd(hfac)3ﾷ2H2O@US-tubes and 26 mM-1s-1 for Gd(thd)3@US-tubes. Compared to the relaxivities obtained for the unloaded chelates (<10 mM-1s-1) as well as accounting for the T1 reduction observed for the empty US-tubes, the boost in relaxivity for chelate-loaded US-tubes is attributed to confinement within the nanotube and depends on the number of coordinated water molecules.
  • Thumbnail Image
    Item
    Stable confinement of PET & MR agents within carbon nanotubes for bimodal imaging
    (Future Medicine Ltd, 2014) Cisneros, Brandon T.; Law, Justin J.; Matson, Michael L.; Azhdarinia, Ali; Sevick-Muraca, Eva M.; Wilson, Lon J.; Richard E. Smalley Institute for Nanoscale Science and Technology
    Simultaneous PET/MR imaging has recently been introduced to the clinic and dual PET/MR imaging probes are rare and of growing interest. We have developed a strategy for producing multimodal probes based on a carbon nanotube platform without the use of chelating ligands. Materials and Methods: Gd3+ and 64Cu2+ ions were loaded into ultra-short single-walled carbon nanotubes (US-tubes) by sonication. Normal, tumor-free athymic nude mice were injected intravenously with the probe and imaged over 48 hrs. Results and Conclusions: The probe was stable for up to 24 hrs when challenged with PBS and mouse serum. PET imaging also confirmed the stability of the probe in vivo for up to 48 hrs. The probe was quickly cleared from circulation, with enhanced accumulation in the lungs. Stable encapsulation of contrast agents within US-tubes represents a new strategy for the design of advanced imaging probes with variable multimodal imaging capabilities.
  • Thumbnail Image
    Item
    Surfactant-free Gd3+-ion-containing carbon nanotube MRI contrast agents for stem cell labeling
    (Royal Society of Chemistry, 2015) Gizzatov, Ayrat; Hernández-Rivera, Mayra; Keshishian, Vazrik; Mackeyev, Yuri; Law, Justin J.; Guven, Adem; Sethi, Richa; Qu, Feifei; Muthupillai, Raja; Cabreira-Hansen, Maria da Graça; Willerson, James T.; Perin, Emerson C.; Ma, Qing; Bryant, Robert G.; Wilson, Lon J.; Richard E. Smalley Institute for Nanoscale Science and Technology
    There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd3+-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca. 35 mg ml−1) without the need of a surfactant. The new materials have extremely high T1-weighted relaxivities of 90 (mM s)−1 per Gd3+ ion at 1.5 T at room temperature and have been used to safely label porcine bone-marrow-derived mesenchymal stem cells for MR imaging. The labeled cells display excellent image contrast in phantom imaging experiments, and TEM images of the labeled cells, in general, reveal small clusters of the CA material located within the cytoplasm with 109 Gd3+ ions per cell.