title: Magnetic nanoclusters exhibiting protein-activated near-infrared fluorescence.
abstract: Composite nanoclusters with chemical, magnetic, and biofunctionality offer broad opportunities for targeted cellular imaging. A key challenge is to load a high degree of targeting, imaging, and therapeutic functionality onto stable metal-oxide nanoparticles. Here we report a route for producing magnetic nanoclusters (MNCs) with alkyne surface functionality that can be utilized as multimodal imaging probes. We form MNCs composed of magnetic Fe(3)O(4) nanoparticles and poly(acrylic acid-co-propargyl acrylate) by the co-precipitation of iron salts in the presence of copolymer stabilizers. The MNCs were surface-modified with near-infrared (NIR) emitting fluorophore used in photodynamic therapy, an azide-modified indocyanine green. The fluorophores engaged and complexed with bovine serum albumin, forming an extended coverage of serum proteins on the MNCs. These proteins isolated indocyanine green fluorophores from the aqueous environment and induced an effective "turn-on" of NIR emission.
authors.affiliation: Center for Optical Materials Science and Engineering Technologies, Department of Materials Science & Engineering, Clemson University, Clemson, South Carolina 29634-0971, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Daniele
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Shaughnessy
authors.forename: Ryan
authors.initials: R
authors.lastname: Roeder
authors.forename: Anthony
authors.initials: A
authors.lastname: Childress
authors.forename: Yuriy P
authors.initials: YP
authors.lastname: Bandera
authors.forename: Stephen
authors.initials: S
authors.lastname: Foulger
mesh_terms: D005453:Fluorescence; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008422:Materials Testing; D011506:Proteins / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D058185:Magnetite Nanoparticles; D011506:Proteins