title: Amphiphilic comblike polymers enhance the colloidal stability of Fe(3)O(4) nanoparticles.
abstract: Stable colloidal dispersions of magnetite (Fe(3)O(4)) nanoparticles (MNPs) were obtained with the inclusion of an amphiphilic comblike polyethylene glycol derivative (CL-PEG) as an amphiphilic polymeric surfactant. Both the size and morphology of the resulting CL-PEG-modified MNPs could be controlled and were characterized by transmission electron microscopy (TEM). The interaction between MNPs and CL-PEG was confirmed by the presence of characteristic infrared absorption peaks, and the colloidal stability of the nanoparticle dispersion in water was evaluated by long-term observation of the dispersion using UV-visible spectroscopy. SQUID measurements confirmed the magnetization of CL-PEG-modified MNPs. The zeta potential of the CL-PEG-modified MNPs showed a dramatic conversion from positive to negative in response to the pH of the surrounding aqueous medium due to the presence of carboxyl groups at the surface. These carboxyl groups can be used to functionalize the MNPs with biomolecules for biotechnological applications. However, regardless of surface electrostatics, the flexible, hydrophilic side chains of CL-PEG-modified MNPs prevented the approach of adjacent nanoparticles, thereby resisting aggregation and resulting in a stable aqueous colloid. The cytotoxicity of MNPs and CL-PEG-modified MNPs was evaluated by a MTT assay.
authors: Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul, Republic of Korea.
authors: Myeongjin
authors: M
authors: Kim
authors: Jaeyeon
authors: J
authors: Jung
authors: Jonghwan
authors: J
authors: Lee
authors: Kyunga
authors: K
authors: Na
authors: Subeom
authors: S
authors: Park
authors: Jinho
authors: J
authors: Hyun
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D003102:Colloids / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry / Q000494:pharmacology; D004355:Drug Stability; D005290:Ferric Compounds / Q000737:chemistry*; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry*
chemical_list: D003102:Colloids; D004337:Drug Carriers; D005290:Ferric Compounds; D014867:Water; C000499:ferric oxide; D011092:Polyethylene Glycols