title: Radiosensitizing effect of zinc oxide and silica nanocomposites on cancer cells.
abstract: Nanoparticulates responsive to X-rays offer increased efficacy of radiation therapy. However, successful demonstrations of such nanoparticle use are limited so far due to lack of significant radiosensitizing effects or poor nanoparticle stability in a biological system. Zinc oxide (ZnO) is the most promising biocompatible material for medicinal applications. In this paper, we report preparation and characterization of scintillating ZnO/SiO2 core-shell nanoparticles. The ZnO/SiO2 nanoparticles absorb ultraviolet (UV) radiation (below 360nm) and emit green fluorescence (400-750nm, maximum 550nm). Under X-ray irradiation (200kVp), the nanoparticles scintillate emitting luminescence in the region 350-700nm (maximum 420nm). The synthesized ZnO/SiO2 nanoparticles are stable in a biologically relevant environment (water and cell growth medium). The potential of the ZnO/SiO2 nanoparticles for radiosensitization is demonstrated in human prostate adenocarcinoma cell lines (LNCaP and Du145). The nanoparticles enhance radiation-induced reduction in cell survival about 2-fold for LNCaP and 1.5-fold for Du145 cells. Radiosensitizing effect can be attributed to X-ray-induced radiocatalysis by the nanoparticles.
authors.affiliation: Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0310 Oslo, Norway; School of Pharmacy, Department of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway.
authors.forename: Roman
authors.initials: R
authors.lastname: Generalov
authors.affiliation: Department of Physics, The University of Texas at Arlington, P.O. Box 19059, 502 Yates Street, 108 Science Hall, Arlington, TX 76019-0059, USA.
authors.forename: Woo Boon
authors.initials: WB
authors.lastname: Kuan
authors.affiliation: Department of Physics, The University of Texas at Arlington, P.O. Box 19059, 502 Yates Street, 108 Science Hall, Arlington, TX 76019-0059, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: School of Pharmacy, Department of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway.
authors.forename: Solveig
authors.initials: S
authors.lastname: Kristensen
authors.affiliation: Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0310 Oslo, Norway. Electronic address: petras.juzenas@rr-research.no.
authors.forename: Petras
authors.initials: P
authors.lastname: Juzenas
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D002470:Cell Survival / Q000528:radiation effects; D006801:Humans; D049449:Luminescence; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D012822:Silicon Dioxide / Q000737:chemistry*; D014407:Tumor Cells, Cultured; D014965:X-Rays; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011838:Radiation-Sensitizing Agents; D012822:Silicon Dioxide; D015034:Zinc Oxide
keywords: Free radicals; Ionizing radiation; Radiation therapy; Radiation-induced catalysis; Radiosensitization