title: Macromolecular cobalt carbonyl complexes encapsulated in a click-cross-linked micelle structure as a nanoparticle to deliver cobalt pharmaceuticals.
abstract: Block copolymers poly(trimethylsilyl propargyl methacrylate)-block-poly(poly(ethylene glycol) methyl ether methacrylate) (P(TMS-PAMA)-b-P(PEGMA)) were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. Subsequent removal of the trimethylsilyl protective groups on the P(TMS-PAMA)(24)-b-P(PEGMA)(40) polymer with tetra-n-butylammonium fluoride hydrate lead to the polymer P(PAMA)(24)-b-P(PEGMA)(40) with pendant alkyne groups, which self-assembled in aqueous solution into micelles with hydrodynamic diameters of less than 20 nm. The alkyne groups in the core took on two functions, acting as a ligand for Co(2)(CO)(8) to generate a derivative of the antitumor agents based on (alkyne)Co(2)(CO)(6) as well as an anchor point for the cross-linking of micelles via click chemistry. The click process was shown to be highly efficient with the two types of cross-linker employed: 1,2-bis-(2-azidoethoxy)ethane and bis-(azidoethyl)disulfide, with almost all of the cross-linker reacting with the micelle at room temperature. The cross-linking density was influenced by the amount of added cross-linker leaving a well-defined amount of alkyne groups that were utilized in the formation of the cobalt complexes. The successful complexation was confirmed via UV/vis and FT-IR spectroscopy. With the formation of (alkyne)Co(2)(CO)(6) moieties in the core, the un-cross-linked and cross-linked micelles were found to almost double in size. The resulting Co-loaded un-cross-linked micelles were observed to be highly toxic to L929 fibroblast cells, while the cross-linking of the micelle was shown to reduce the toxicity.
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD), School of Chemical Sciences and Engineering, University of New South Wales, Sydney, Australia.
authors.forename: Alexander B J
authors.initials: AB
authors.lastname: Withey
authors.forename: Gaojian
authors.initials: G
authors.lastname: Chen
authors.forename: T L Uyen
authors.initials: TL
authors.lastname: Nguyen
authors.forename: Martina H
authors.initials: MH
authors.lastname: Stenzel
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000737:chemistry; D045744:Cell Line, Tumor; D003035:Cobalt / Q000008:administration & dosage* / Q000737:chemistry; D004337:Drug Carriers; D005347:Fibroblasts / Q000187:drug effects; D051379:Mice; D008823:Micelles; D053758:Nanoparticles / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; D008823:Micelles; D011109:Polymethacrylic Acids; D003035:Cobalt; C529955:dicobalt octacarbonyl