title: Synthesis of manganese ferrite/graphene oxide nanocomposites for biomedical applications.
abstract: In this study, MnFe(2)O(4) nanoparticle (MFNP)-decorated graphene oxide nanocomposites (MGONCs) are prepared through a simple mini-emulsion and solvent evaporation process. It is demonstrated that the loading of magnetic nanocrystals can be tuned by varying the ratio of graphene oxide/magnetic nanoparticles. On top of that, the hydrodynamic size range of the obtained nanocomposites can be optimized by varying the sonication time during the emulsion process. By fine-tuning the sonication time, MGONCs as small as 56.8 ± 1.1 nm, 55.0 ± 0.6 nm and 56.2 ± 0.4 nm loaded with 6 nm, 11 nm, and 14 nm MFNPs, respectively, are successfully fabricated. In order to improve the colloidal stability of MGONCs in physiological solutions (e.g., phosphate buffered saline or PBS solution), MGONCs are further conjugated with polyethylene glycol (PEG). Heating by exposing MGONCs samples to an alternating magnetic field (AMF) show that the obtained nanocomposites are efficient hyperthermia agents. At concentrations as low as 0.1 mg Fe mL(-1) and under an 59.99 kA m(-1) field, the highest specific absorption rate (SAR) recorded is 1588.83 W g(-1) for MGONCs loaded with 14 nm MFNPs. It is also demonstrated that MGONCs are promising as magnetic resonance imaging (MRI) T(2) contrast agents. A T(2) relaxivity value (r(2) ) as high as 256.2 (mM Fe)(-1) s(-1) could be achieved with MGONCs loaded with 14 nm MFNPs. The cytotoxicity results show that PEGylated MGONCs exhibit an excellent biocompatibility that is suitable for biomedical applications.
authors.affiliation: Department of Materials Science & Engineering, Faculty of Engineering, National University of Singapore (NUS), 7 Engineering Drive 1, Singapore.
authors.forename: Erwin
authors.initials: E
authors.lastname: Peng
authors.forename: Eugene Shi Guang
authors.initials: ES
authors.lastname: Choo
authors.forename: Prashant
authors.initials: P
authors.lastname: Chandrasekharan
authors.forename: Chang-Tong
authors.initials: CT
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Ding
authors.forename: Kai-Hsiang
authors.initials: KH
authors.lastname: Chuang
authors.forename: Jun Min
authors.initials: JM
authors.lastname: Xue
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry* / Q000633:toxicity; D006108:Graphite / Q000737:chemistry* / Q000633:toxicity; D006801:Humans; D061986:MCF-7 Cells; D017895:Manganese Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000633:toxicity; D036103:Nanotechnology; D011092:Polyethylene Glycols / Q000737:chemistry; D014407:Tumor Cells, Cultured
chemical_list: D001672:Biocompatible Materials; D005290:Ferric Compounds; D017895:Manganese Compounds; C551151:manganese ferrite; D011092:Polyethylene Glycols; D006108:Graphite