Browsing by Author "Hawkett, BS"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Phase behavior of amphiphilic diblock co-oligomers with nonionic and ionic hydrophilic groups
    (American Chemical Society, 2013-03-14) Heinen, JM; Blom, ACM; Hawkett, BS; Warr, GG
    The synthesis of a series of co-oligomer amphiphiles by RAFT and their self-assembly behavior in water is described. These novel amphiphiles, comprised of styrene, butyl acrylate, and alkyl hydrophobes together with ionic acrylic acid and nonionic hydroxyethylacrylate hydrophilic moieties and with a total degree of polymerization from 5 to 17, represent a new class of small-molecule surfactants that can be formed from the immense potential library of all polymerizable monomers. Examples of micellar solutions and discrete cubic, hexagonal, lamellar, and inverted hexagonal lyotropic phases, as well as vesicle dispersions and coexisting lamellar phases, are reported and characterized by small-angle scattering. The variation of self-assembly structure with co-oligomer composition, concentration, and solution conditions is interpreted by analogy with the surfactant packing parameter used for conventional small-molecule amphiphiles.© 2013, American Chemical Society.
  • Thumbnail Image
    Item
    Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles
    (Dove Press Ltd, 2017-01-27) Pham, THN; Lengkeek, NA; Greguric, I; Kim, BJ; Pellegrini, PA; Bickley, SA; Tanudji, MR; Jones, SK; Hawkett, BS; Pham, BTT
    Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT)-magnetic resonance imaging (MRI) were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3) nanoparticles (SPIONs). The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG) or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS). All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe. © 2017 Dove Press Ltd under Creative Commons v3.0, BY, NC.