title: Hydrophilic Monodisperse Magnetic Nanoparticles Protected by an Amphiphilic Alternating Copolymer.
abstract: Iron oxide nanoparticles (NPs) with diameters of 16.1, 20.5, and 20.8 nm prepared from iron oleate precursors were coated with poly(maleic acid-alt-1-octadecene) (PMAcOD). The coating procedure exploited hydrophobic interactions of octadecene and oleic acid tails while hydrolysis of maleic anhydride moieties allowed the NP hydrophilicity. The PMAcOD nanostructure in water and the PMAcOD-coated NPs were studied using transmission electron microscopy, zeta-potential measurements, small-angle X-ray scattering, and fluorescence measurements. The combination of several techniques suggests that independently of the iron oxide core and oleic acid shell structures, PMAcOD encapsulates NPs, forming stable hydrophilic shells which withstand absorption of hydrophobic molecules, such as pyrene, without shell disintegration. Moreover, the PMAcOD molecules are predominantly attached to a single NP instead of self-assembling into the PMAcOD disklike nanostructures or attachment to several NPs. This leads to highly monodisperse aqueous samples with only a small fraction of NPs forming large aggregates due to cross-linking by the copolymer macromolecules.
authors.affiliation: Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia.
authors.forename: Eleonora V
authors.initials: EV
authors.lastname: Shtykova
authors.forename: Xinlei
authors.initials: X
authors.lastname: Huang
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Gao
authors.forename: Jason C
authors.initials: JC
authors.lastname: Dyke
authors.forename: Abrin L
authors.initials: AL
authors.lastname: Schmucker
authors.forename: Bogdan
authors.initials: B
authors.lastname: Dragnea
authors.forename: Nicholas
authors.initials: N
authors.lastname: Remmes
authors.forename: David V
authors.initials: DV
authors.lastname: Baxter
authors.forename: Barry
authors.initials: B
authors.lastname: Stein
authors.forename: Peter V
authors.initials: PV
authors.lastname: Konarev
authors.forename: Dmitri I
authors.initials: DI
authors.lastname: Svergun
authors.forename: Lyudmila M
authors.initials: LM
authors.lastname: Bronstein