title: Cross-linked antioxidant nanozymes for improved delivery to CNS.
abstract: Formulations of antioxidant enzymes, superoxide dismutase 1 (SOD1, also known as Cu/Zn SOD) and catalase were prepared by electrostatic coupling of enzymes with cationic block copolymers, polyethyleneimine-poly(ethylene glycol) or poly(L-lysine)-poly(ethylene glycol), followed by covalent cross-linking to stabilize nanoparticles (NPs). Different cross-linking strategies (using glutaraldehyde, bis-(sulfosuccinimidyl)suberate sodium salt or 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride with N-hydroxysulfosuccinimide) and reaction conditions (pH and polycation/protein charge ratio) were investigated that allowed immobilizing active enzymes in cross-linked NPs, termed "nanozymes." Bienzyme NPs, containing both SOD1 and catalase were also formulated. Formation of complexes was confirmed using denaturing gel electrophoresis and western blotting; physicochemical characterization was conducted using dynamic light scattering and atomic force microscopy. In vivo studies of (125)I-labeled SOD1-containing nanozymes in mice demonstrated their increased stability in both blood and brain and increased accumulation in brain tissues, in comparison with non-cross-linked complexes and native SOD1. Future studies will evaluate the potential of these formulations for delivery of antioxidant enzymes to the central nervous system to attenuate oxidative stress associated with neurological diseases.
  
  
  BACKGROUND
  Formulations of antioxidant enzyme complexes were demonstrated along with their increased stability in both blood and brain and increased accumulation in CNS tissue. Future studies will evaluate the potential of these formulations for antioxidant enzyme deliver to the CNS to attenuate oxidative stress in neurodegenerative diseases.
authors.affiliation: Department of Chemical Enzymology, Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Natalia L
authors.initials: NL
authors.lastname: Klyachko
authors.forename: Devika S
authors.initials: DS
authors.lastname: Manickam
authors.forename: Anna M
authors.initials: AM
authors.lastname: Brynskikh
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Uglanova
authors.forename: Shu
authors.initials: S
authors.lastname: Li
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Higginbotham
authors.forename: Tatiana K
authors.initials: TK
authors.lastname: Bronich
authors.forename: Elena V
authors.initials: EV
authors.lastname: Batrakova
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kabanov
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry; D001921:Brain / Q000378:metabolism* / Q000648:ultrastructure; D002374:Catalase / Q000097:blood / Q000737:chemistry* / Q000648:ultrastructure; D002417:Cattle; D002460:Cell Line; D002490:Central Nervous System; D016503:Drug Delivery Systems; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005976:Glutaral / Q000737:chemistry; D007457:Iodine Radioisotopes; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009474:Neurons; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013482:Superoxide Dismutase / Q000097:blood / Q000737:chemistry* / Q000648:ultrastructure; D000072105:Superoxide Dismutase-1
chemical_list: D000975:Antioxidants; D004800:Enzymes, Immobilized; D007457:Iodine Radioisotopes; D011108:Polymers; D011092:Polyethylene Glycols; D002374:Catalase; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D005976:Glutaral