title: Novel POSS-PCU Nanocomposite Material as a Biocompatible Coating for Quantum Dots.
abstract: Quantum dots (QDs) are fluorescent nanoparticles with unique photophysical properties that enable them to potentially replace traditional organic dyes and fluorescent proteins in various bioimaging applications. However, the inherent toxicity of their cores based on cadmium salts limits their widespread biomedical use. We have developed a novel nanocomposite polymer emulsion based on polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) that can be used to coat quantum dots to nullify their toxicity and enhance photostability. Here we report the synthesis and characterization of a novel POSS-PCU nanocomposite polymer emulsion and describe its application for coating QDs for biological application. The polymer was synthesized by a process of emulsion polymerization and formed stable micelles of ∼33 nm in diameter. CdTe/CdS/ZnS QDs were efficiently stabilized by the polymer emulsion through encapsulation within the polymer micelles. Characterization studies showed no significant change in the unique photophysical properties of QDs after coating. The polymer was biocompatible to HepG2, HUVECs, and mouse skeletal muscle cells at 2.5% after 24 h exposure on in vitro testing. Polymer encapsulated QDs showed enhanced photostability on exposure to high degrees of UV irradiation and air as well as significantly reduced cytotoxicity on exposure to HepG2 cells at 30 μg/mL for 24 h. We have therefore concluded that the POSS-PCU polymer emulsion has the potential to make a biocompatible and photostable coating for QDs enabling a host of biomedical applications to take this technology to the next level.
authors.affiliation: Centre for Nanotechnology & Regenerative Medicine, UCL Division of Surgery & Interventional Science, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Sarwat B
authors.initials: SB
authors.lastname: Rizvi
authors.affiliation: Centre for Nanotechnology & Regenerative Medicine, UCL Division of Surgery & Interventional Science, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Shi Yu
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Department of Physics, King's College London , London WC2R 2LS, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Green
authors.affiliation: Centre for Nanotechnology & Regenerative Medicine, UCL Division of Surgery & Interventional Science, University College London , London WC1E 6BT, United Kingdom.|Royal Free Hampstead NHS Trust Hospital , London NW3 2QG, United Kingdom.
authors.forename: Mo
authors.initials: M
authors.lastname: Keshtgar
authors.affiliation: Centre for Nanotechnology & Regenerative Medicine, UCL Division of Surgery & Interventional Science, University College London , London WC1E 6BT, United Kingdom.|Royal Free Hampstead NHS Trust Hospital , London NW3 2QG, United Kingdom.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D002478:Cells, Cultured; D004655:Emulsions / Q000737:chemistry / Q000633:toxicity; D056945:Hep G2 Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D008422:Materials Testing; D051379:Mice; D053761:Nanocomposites / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D010782:Photolysis; D045663:Quantum Dots / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D014466:Ultraviolet Rays
chemical_list: D001672:Biocompatible Materials; D004655:Emulsions; C000610393:POSS-PCU polymer