  Bio-spinterfaces present numerous opportunities to study spintronics across
the biomolecules attached to (ferro)magnetic electrodes. While it offers
various exciting phenomena to investigate, it's simultaneously challenging to
make stable bio-spinterfaces, as biomolecules are sensitive to many factors
that it encounters during thin-film growth to device fabrication. The
chirality-induced spin-selectivity (CISS) effect is an exciting discovery
demonstrating an understanding that a specific electron's spin (either UP or
DOWN) passes through a chiral molecule. The present work utilizes Ustilago
maydis Rvb2 protein, an ATP-dependent DNA helicase (also known as Reptin) for
the fabrication of bio-spintronic devices to investigate spin-selective
electron transport through protein. Ferromagnetic materials are well-known for
showing spin-polarization, which many chiral and biomolecules can mimic. We
report spin-selective electron transmission through Rvb2 that exhibits 30% spin
polarization at a low bias (+ 0.5 V) in a device configuration, Ni/Rvb2
protein/ITO measured under two different magnetic configurations. Our findings
demonstrate that biomolecules can be put in circuit components without any
expensive vacuum deposition for the top contact. Thus, it holds a remarkable
potential to advance spin-selective electron transport in other biomolecules
such as proteins, and peptides for biomedical applications.
