TITLE:
Generation of Reactive Oxygen Species (ROS) on the Surface of Severe Plastically Deformed Pure Copper Processed by High-Pressure Torsion (HPT)
AUTHORS:
Ken Hirota, Kento Kominami, Aoi Horinouchi, Kazuhiko Tsukagoshi, Hiroshi Kawakami, Kaveh Edalati, Takashi Ozawa
KEYWORDS:
Copper, High-Pressure Torsion, Antibacterial Activity, Reactive Oxygen Species, Chemiluminescence
JOURNAL NAME:
Materials Sciences and Applications,
Vol.17 No.2,
February
9,
2026
ABSTRACT: To investigate the antibacterial activity of severe plastically deformed pure Cu by high-pressure torsion (HPT), the generation of reactive oxygen species (ROS) which might be the main origin of antibacterial activity of Cu, Cu disc (1.00 × 10−2 m in diameter, 1.0 × 10−3 m thick) has been evaluated using chemiluminescence (CL) with the luminol solution; HPT processes were performed under various torsion turns, 0, 1/4, 1, 3 and 10 turns under uniaxial pressure of 6.0 GPa and rotating speed of 1.667/s (1.0 rpm) at room temperature. Cu disc which was HPT-processed with the 1/4 turn, simply denoted as HPT1/4 Cu disc, showed the highest summation of CL intensity, ΣCL, among those of other HPTed discs, and this value was 2.7 times higher than that of as-obtained disc. Furthermore, HPT1/4 disc heated at 523 K (250˚C) in a vacuum (2 × 10−3 Pa) for 1.8 × 103 s (30 min) brought much higher ΣCL value, about 35 times of as-obtained disc. Then, the components of ROS generated were investigated using the combination of luminol + scavengers corresponding to each ROS. About 45% of ROS were strong antibacterial active hydroxy radical ·OH and hydrogen peroxide H2O2.