Photo-induced Electron Transfer from Hematite and Zinc Oxide Nanostructures to Cytochrome C: Systems Applicable to Spintronics

Author(s)

Menezes, Lucivaldo R. ; Lopes, David M. ; Bronzato, Julia D. ; Sombrio, Guilherme ; Criado, Denise ; Zuniga, Alejandro ; Lanfredi, Alexandre J. C. ; Souza, Jose A. ; Nantes-Cardoso, Iseli L. ; IEEE

• Document type: Journal article
• Source: 2019 IEEE 9TH INTERNATIONAL NANOELECTRONICS CONFERENCES (INEC); v. N/A, p. 8-pg., 2019-01-01.

Abstract

Cytochrome c is a protein covalently bound to the iron protoporphyrin IX (heme) with electronic and magnetic properties applicable in spintronics and energy. The cytochrome c protein chain is folded in a chiral structure (a-helix) that is responsible for the chiral-induced spin selectivity (CISS) applicable to spintronics and energy. The helicoidal structure of cytochrome c is associated to a redox center, a Fe(III) porphyrin, that can accept electrons from the conduction band of semiconductors to be converted to the Fe(II) form. Considering a possible connection between redox reactions of cytochrome c with its spin selectivity property and stability, the present study focused on the processes that modulate the photo-induced electron transfer from semiconductors to Fe(III) porphyrin of cytochrome c. Two semiconductors, ZnO and Fe2O3, structured as layers of nanowires (NWs) and nanoflakes (NFs), named as ZnONWs and Fe(2)O(3)NWs(NFs), vertically grown on different substrates, were studied. Under illumination with a sunlight simulator, the Fe(2)O(3)NWs( NFs) efficiently converted Fe(III) cytochrome c to the Fe(II) state, while ZnONWs promoted oxidative damages on the protein. Decoration of Fe(2)O(3)NWs(NFs) with gold nanoparticles impaired cytochrome c photoreduction. The analysis of the pro-oxidant species produced by ZnONWs and Fe(2)O(3)NWs(NFs) revealed that the high production of hydrogen peroxide by ZnO material was the main responsible for the inefficient cytochrome c reduction. Hydrogen peroxide production by ZnO resulted from superoxide ion disproportionation rather than from hydroxyl radical produced by water splitting and, consequently, was not influenced by cytochrome c spin filtering as demonstrated for the photoelectrochemical systems. (AU)

• FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
• Grantee: Adalberto Fazzio
• Support Opportunities: Research Projects - Thematic Grants