title: Well-Defined SiO2@P(EtOx-stat-EI) Core-Shell Hybrid Nanoparticles via Sol-Gel Processes.
abstract: Positively charged nanoparticles (NPs) are very interesting for biomedical and pharmaceutical applications, such as nonviral gene delivery. Here, the synthesis of SiO2 nanoparticles with a covalently grafted poly(2-ethyl-2-oxazoline) (PEtOx) shell (SiO2@PEtOx) is presented. PEtOx with a degree of polymerization of 20 and 38 is synthesized via microwave supported cationic ring-opening polymerization and subsequently end-functionalized with a triethoxysilyl linker for subsequent grafting to silica particles with hydrodynamic radii of 7, 31, and 152 nm. The resulting SiO2@PEtOx particles are characterized by using dynamic light scattering (DLS), transmission electron microscopy (TEM, cryoTEM), and scanning electron microscopy (SEM) to determine changes in particle size. Thermal gravimetrical analysis is used to quantify the amount of polymer on the silica surface. Subsequent in situ transformation of SiO2@PEtOx particles into SiO2@P(EtOx-stat-EI) (poly(2-ethyl-2-oxazoline-stat-ethylene imine) grafted silica particles) under acidic conditions inverts the surface charge from negative to positive according to ζ-potential measurements. The P(EtOx-stat-EI) shell could be used for the deposition of Au NP afterward.
authors.affiliation: Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.|Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Eckardt
authors.affiliation: Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.|Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Pietsch
authors.affiliation: Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.|Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Zumann
authors.affiliation: Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.|Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: von der Lühe
authors.affiliation: Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Fraunhoferstr. 6, 07743, Jena, Germany.
authors.forename: Delia S
authors.initials: DS
authors.lastname: Brauer
authors.affiliation: Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.|Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
authors.forename: Felix H
authors.initials: FH
authors.lastname: Schacher
mesh_terms: D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011073:Polyamines; D011108:Polymers; C511916:poly(2-ethyl-2-oxazoline); D012822:Silicon Dioxide
keywords: core-shell nanoparticles; hybrid materials; poly(2-ethyl-2-oxazoline); poly(ethylene imine)