Umeda Shuntaro, Shibata Shinichiro, Koishikawa Atsushi, Watanabe Takamichi, Ohara Hirotaka, Itoh Naoya, Matsushima Asako
Microbiology Department Nagoya City Public Health Research Institute, Nagoya, Japan.
Thermal Products Development Department, Research & Development Center, Marketing & Technology Division, UACJ Corporation, Chiyoda-ku, Japan.
BMC Microbiol. 2025 Aug 12;25(1):502. doi: 10.1186/s12866-025-04265-0.
Healthcare-associated infections (HAIs) are serious public health issues, and environmental surfaces contaminated with microorganisms have been reported to play an important role in their occurrence. We focused on copper, which is known to have excellent antimicrobial activity, as a measure to prevent contamination of environmental surfaces. In hospital environments, copper has been used on handrails and doorknobs. However, its use has been limited because of its opaque nature. Therefore, we developed a thin, highly transparent copper film via the sputtering method. This study examines the antimicrobial activity of this transparent film to expand the potential applications of copper to commonly used surfaces in healthcare settings.
Polyethylene terephthalate film was coated with a copper layer of four different thicknesses via the sputtering method. The antimicrobial activity of the copper film was evaluated according to the ISO22196:2011 standards. The antimicrobial activity and the change in the viable bacteria count with contact time between the test bacteria and the copper film surface were evaluated.
For all copper layer thicknesses, the bacterial count decreased exponentially after contact with the copper film. For Escherichia coli, the count decreased 100-fold after 10 min, and no viable bacteria were observed within 30 min. For Staphylococcus aureus, the count decreased 100-fold after 20 min, and no viable bacteria were observed within 50 min. In these two bacterial species, the antibacterial activity did not differ according to the thickness of the copper layer.
All copper films showed sufficient antimicrobial activity against Escherichia coli and Staphylococcus aureus regardless of the copper layer thickness. The thinnest 5 nm copper film with high transparency was considered most useful for medical applications because of its visibility. Further study is needed to determine whether this transparent copper film reduces microbial contamination on environmental surfaces and contributes to reducing HAIs in hospitals and healthcare facilities.
医疗保健相关感染（HAIs）是严重的公共卫生问题，据报道，被微生物污染的环境表面在其发生过程中起着重要作用。我们关注到铜具有出色的抗菌活性，将其作为预防环境表面污染的一种措施。在医院环境中，铜已被用于扶手和门把手上。然而，由于其不透明的性质，其使用受到限制。因此，我们通过溅射法制备了一种薄的、高度透明的铜膜。本研究考察了这种透明膜的抗菌活性，以扩大铜在医疗保健环境常用表面的潜在应用。
通过溅射法在聚对苯二甲酸乙二酯薄膜上涂覆四种不同厚度的铜层。根据ISO22196:2011标准评估铜膜的抗菌活性。评估了抗菌活性以及测试细菌与铜膜表面接触时间内活菌数的变化。
对于所有铜层厚度，与铜膜接触后细菌数量呈指数下降。对于大肠杆菌，接触10分钟后数量下降100倍，30分钟内未观察到活菌。对于金黄色葡萄球菌，接触20分钟后数量下降100倍，50分钟内未观察到活菌。在这两种细菌中，抗菌活性不因铜层厚度而异。
无论铜层厚度如何，所有铜膜对大肠杆菌和金黄色葡萄球菌均表现出足够的抗菌活性。最薄的5纳米高透明铜膜因其可视性被认为对医疗应用最有用。需要进一步研究以确定这种透明铜膜是否能减少环境表面的微生物污染，并有助于减少医院和医疗保健设施中的医疗保健相关感染。
