Maghemite Nanoparticles with Enhanced Magnetic Properties: One Pot Preparation and Ultrastable Dextran Shell

作者：Di Corato Riccardo; Alois Alessandra; Rena Simona; Greneche Jean Marc; Pugliese Giammarino; Pellegrino Teresa; Malitesta Cosimino; Rinaldi Rosaria^*

来源：ACS Applied Materials & Interfaces, 2018, 10(24): 20271-20280.

DOI：10.1021/acsami.7b18411

• magnetic nanoparticles
• magnetic characterization
• XPS
• Fe-57 Mossbauer spectrometry
• water transferring
• dextran

In the field of nanomedicine, superparamagnetic nanoparticles are one of the most studied nanomaterials for theranostics. In this study, a one-pot synthesis of magnetic nanoparticles is presented, with an increased control on particle size from 10 to 40 nm. Monitoring of vacuum level is introduced here as a crucial parameter for achieving a fine particle morphology. The magnetic properties of these nanoparticles are highly affected by disorders or mismatches in crystal structure. A prolonged oxidation step is applied to the obtained nanoparticles to transform the magnetic phases into a pure maghemite one, confirmed by high-resolution X-ray photoelectron spectroscopy analysis, by Mossbauer spectrometry and, indirectly, by increased performances in magnetization curves and in relaxation times. Afterward, the attained nanoparticles are transferred into water by a nonderivatized dextran coating. Thermogravimetric analysis confirms that polysaccharide molecules replace oleic acid on the surface by stabilizing the particles in the aqueous phase and culture media. Preliminary in vitro test reveals that the dextran-coated nanoparticles are not passively internalized from the cells. As a proof of concept, a secondary layer of chitosan assures a positive charge to the nanoparticle surface, thus enhancing cellular internalization.

• 出版日期2018-6-20