title: Evaluation of nickel ferrite nanoparticles coated with oleylamine by NMR relaxation measurements and magnetic hyperthermia.
abstract: Nickel ferrite nanoparticles were synthesized via a facile solvothermal approach. Oleylamine (OAm) was used in all synthetic procedures as a stabilizing agent and solvent. By varying the polarity of the solvents, hydrophobic NiFe2O4 nanoparticles coated with OAm of relatively similar sizes (9-11.7 nm) and in a range of magnetization values (32.0-53.5 emu g(-1)) were obtained. The as-prepared hydrophobic nanoparticles were characterized by XRD, TEM, SEM, TGA and VSM and converted to hydrophilic by two different approaches. The addition of a positively charged ligand (cetyltrimethyl ammonium bromide, CTAB) and the ligand exchange procedure (2,3-dimercaptosuccinic acid, DMSA) have been successfully applied. The aqueous suspensions of NiFe2O4@CTAB and NiFe2O4@DMSA showed good colloidal stability after a long period of time. The different surface modification affected both the NMR relaxometric measurements and the hyperthermia effects. In both techniques CTAB modification demonstrated higher r2 relaxivity (278.9 s(-1) mM(-1) in an NMR spectrometer at 11.7 T) and SAR values (423.4 W g(-1) at an applied AC field with a particle concentration of 0.5 mg mL(-1)). The results indicate that a coating with a larger molecule as CTAB under the same size, shape and magnetization of NiFe2O4 NPs gave rise to NMR relaxometric properties and heating efficacy.
authors.affiliation: Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. samkat@chem.auth.gr.
authors.forename: M
authors.initials: M
authors.lastname: Menelaou
authors.forename: K
authors.initials: K
authors.lastname: Georgoula
authors.forename: K
authors.initials: K
authors.lastname: Simeonidis
authors.forename: C
authors.initials: C
authors.lastname: Dendrinou-Samara
mesh_terms: D000588:Amines / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D006358:Hot Temperature; D060328:Magnetic Phenomena; D009682:Magnetic Resonance Spectroscopy; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009532:Nickel / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D004113:Succimer / Q000737:chemistry
chemical_list: D000588:Amines; D002593:Cetrimonium Compounds; D005290:Ferric Compounds; D012997:Solvents; C550717:nickel ferrite; D009532:Nickel; D004113:Succimer; D000077286:Cetrimonium; C008703:oleylamine