title: Efficient Radioisotope Energy Transfer by Gold Nanoclusters for Molecular Imaging.
abstract: Beta-emitting isotopes Fluorine-18 and Yttrium-90 are tested for their potential to stimulate gold nanoclusters conjugated with blood serum proteins (AuNCs). AuNCs excited by either medical radioisotope are found to be highly effective ionizing radiation energy transfer mediators, suitable for in vivo optical imaging. AuNCs synthesized with protein templates convert beta-decaying radioisotope energy into tissue-penetrating optical signals between 620 and 800 nm. Optical signals are not detected from AuNCs incubated with Technetium-99m, a pure gamma emitter that is used as a control. Optical emission from AuNCs is not proportional to Cerenkov radiation, indicating that the energy transfer between the radionuclide and AuNC is only partially mediated by Cerenkov photons. A direct Coulombic interaction is proposed as a novel and significant mechanism of energy transfer between decaying radionuclides and AuNCs.
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Volotskova
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Conroy
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Jason H
authors.initials: JH
authors.lastname: Stafford
authors.affiliation: Stanford Nanocharacterization Laboratory, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Ai Leen
authors.initials: AL
authors.lastname: Koh
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Bianxiao
authors.initials: B
authors.lastname: Cui
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Guillem
authors.initials: G
authors.lastname: Pratx
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Xing
mesh_terms: D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D004735:Energy Transfer; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D011868:Radioisotopes / Q000737:chemistry*; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine
chemical_list: D011868:Radioisotopes; D012710:Serum Albumin, Bovine; D006046:Gold
keywords: cerenkov radiation; gold nanoclusters; imaging, radioisotope energy transfer; optical imaging; radioisotopes