Surface treatment method for copper or copper alloy, surface treatment liquid for sterilizing copper or copper alloy, and sterilization method using copper or copper alloy treated by said method

#The present invention relates to a surface treatment method for copper or a copper alloy, a surface treatment liquid for sterilizing copper or a copper alloy, and a sterilization method using copper or a copper alloy treated by the method.

#In recent years, the spread of antimicrobial-resistant bacteria and viruses having resistance to antimicrobials and antivirals has been regarded as a serious problem. A collaborative study between the UK Government and the Wellcome Trust estimates that 10 million people across the world will die by 2050 because of antimicrobial-resistant bacteria (Review on Antimicrobial Resistance. Antimicrobial Resistance: Tackling a Crisis for the Health and Wealth of Nations. 2014). This number exceeds the number of cancer fatalities each year, and the associated economic loss is estimated at about 100 trillion dollars. WHO's global action plan against infection caused by antimicrobial-resistant bacteria (Global Action Plan on Antimicrobial Resistance. World Health Organization. 2015) requires urgent action to deal with a flurry of development of antimicrobial resistance. The document also describes how to reduce the incidence of infection, how to optimize the use of antimicrobials, and the importance in complying with the optimal use.

#In the midst of growing threats caused by antimicrobial-resistant bacteria and viruses, metallic copper (hereinafter also simply referred to as “copper”) and alloys thereof are attracting attention as new antimicrobial and antiviral materials. This is because materials' surfaces touched by human hands are confirmed to play an important role in preventing infection. A material surface is not only a source of infection due to bacteria attached to the surface from human hands but also a cause of horizontal transfer of antimicrobial-resistance genes due to coexistence of several types of bacteria. Therefore, not only new antimicrobial-resistant bacteria but also multiantimicrobial-resistant bacteria may be generated. In order to prevent the generation of such bacteria, continuous disinfection of materials surfaces is necessary, and copper and copper alloys have attracted attention as such materials. It is reported that a surface of copper and a copper alloy exhibits strong bactericidal actions which destroy bacteria attached to the surface and degrade DNA of the bacteria in about several tens of minutes to several hours. Due to the gene degradation, it is determined that copper and copper alloys do not cause horizontal transfer that generates new antimicrobial-resistant bacteria and that copper and copper alloys are effective against many types of pathogens such as viruses and fungi as well as bacteria.

#FIG. 1 shows results of hydrogen peroxide (H2O2) generation amounts measured in Example 1 by immersing sample pieces of Cu, CBRI, CBRA, and C6932 in reducing agent solutions containing different biological reducing substances.

#FIG. 2 shows results of hydrogen peroxide (H2O2) generation amounts measured in Example 1 by immersing a Cu sample piece in reducing agent solutions containing different biological reducing substances.

#FIG. 3 shows results of hydrogen peroxide (H2O2) generation amounts measured in Example 2 by immersing sample pieces of Cu, C2680, CBRI, and CBRA in reducing agent solutions containing GSH having different concentrations.

#Hereinafter, embodiments of the present invention will be described.

#A surface treatment method for copper or a copper alloy according to an embodiment of the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating a surface of copper or a copper alloy with the reducing agent solution.

#In the surface treatment method according to this embodiment, first, a reducing agent solution containing a biological reducing substance is prepared.