Magnetic nanoparticles as a support for a copper (II) complex with nuclease activity

• Published in: Journal of inorganic biochemistry 2018-09, Vol.186, p.294-300
• Main Authors: Silva, Maria A.S., Romo, Adolfo I.B., Abreu, Dieric S., Carepo, Marta S.P., Lemus, Luis, Jafelicci, Miguel, Paulo, Tércio F., Nascimento, Otaciro R., Vargas, Esteban, Denardin, Juliano C., Diógenes, Izaura C.N.
• Format: Article
• Language: English
• Subjects: Copper complex; Core-shell magnetic nanoparticles; DNA nuclease activity; Hydroxyl radical; Reactive oxygen species
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2018.06.015

Magnetic nanoparticles have been extensively explored for the development of platforms for drug delivery and imaging probes. In this work, we have used a modular capping strategy to produce magnetic gold-coated Fe3O4 (Fe3O4@Au) nanoparticles, which have been decorated with a copper (II) complex containing a thioether derivative of clip-phen (Fe3O4@Au@Cu), where the complex [Cu(2CP-Bz-SMe)]2+ has affinity to bind DNA and proven nuclease activity (2CP-Bz-SMe=1,3-bis((1,10-phenanthrolin-2-yl)oxy)-N-(4-(methylthio)benzylidene)propan-2-imine). The functionalization of Fe3O4@Au with the copper complex occurs through the sulfur atom of the thioether moiety, as indicated by Raman scattering on surface. The magnetic measurements showed the nanomaterial Fe3O4@Au@Cu is still magnetic although the gold shell and the functionalization with the copper complex have diminished the magnetization due to the dilution of the magnetic core. The nuclease assays performed with Fe3O4@Au@Cu indicate that the nuclease activity of the nanomaterial toward the plasmid DNA involves an oxidative pathway in which H2O2 species is involved as intermediate in a Fenton-like reaction. Based on the electron paramagnetic resonance spectra (aN = 15.07 G, aH = 14.99 G), such nuclease activity is assigned, essentially, to the HO species indicating that the radical production property of [Cu(2CP-Bz-SMe)]2+ is successfully transferred to the core-shell gold-coated Fe3O4 magnetic nanoparticles. To the best of our knowledge, this is the first study reporting nuclease activity due to the reactive oxygen species generated by a copper complex immobilized on a gold-coated magnetic nanoparticle. This work presents a comprehensive study on the functionalization of magnetic gold-coated Fe3O4 nanoparticles with a copper complex containing a thioether derivative of bis-phenanthroline, which show nuclease activity toward DNA due to reactive oxygen species generation. [Display omitted] •Magnetic gold-coated nanoparticles (NPs) decorated with phenanthroline-Cu(II) complex.•NPs are magnetic after gold coating and the functionalization with the complex.•DNA-nuclease activity of NPs is assigned to HO produced by a Fenton-like reaction.•Radical generation property of complex is successfully transferred to magnetic NPs.