具有不同粗糙度的热喷涂铜合金涂层的杀灭芽孢效果

Sporicidal efficacy of thermal spray copper alloy coating with varying degrees of roughness

本文研究了铜合金板和铜合金涂层两种不同表面上的生物杀灭效果。内孢在休眠状态下存活数个世纪,我们的工作比较了铜合金涂层和板材对内生孢子的杀灭效果。采用双丝电弧喷涂系统,在不锈钢试片上进行了喷涂。喷涂原料为Cu-Ni-Zn线材,涂层厚度为400μm。铜合金板材具有相同的组分,并被环境保护署(美国)注册为抗菌素。所有实验中,采用没有涂层的不锈钢试片进行对照试验。表面粗糙度值具有两个值,Ra=3.5μm和Ra=0.1μm。采用接触式轮廓仪和三维图像分析了表面形貌。用EDS和FIB表征元素组成和纳米结构和内生孢子的花状结构。研究结果表明:粗糙度(Ra值0.1和3.5μm)的不同,并没有显著影响板材和涂层上大肠杆菌的生物活性。在5分钟内,这种涂层和EPA认证的金属薄片一样有效地破坏了营养细胞。研究表明,枯草芽孢杆菌内生孢子的降解在暴露于涂层后2小时内开始。七天后两个表面上仅有广泛退化的内生孢子和纳米结构可见。结果表明,热喷涂铜合金涂层与认证的抗菌金属板材在数小时内破坏内生孢子同样有效;在一周后,涂层的效果更佳。

This study was focused on the biocidal efficacy on spores of copper alloy sheet and copper alloy coating at two different surface topographies. Endospores can remain viable in a dormant state for centuries. Our work compares the effectiveness in killing endospores of copper alloy coating and sheet metal. A twin-wire arc spray system was used for coating of stainless steel coupons. The feedstock was CuNiZn wire, the coating thickness was 400 μm. The copper alloy sheet metal had the same composition and is registered as antimicrobial by Environmental Protection Agency （US）. Uncoated stainless steel coupons were used as controls in all experiments. The surface was polished to two roughness levels Ra=3.5 μm, and Ra=0.1 μm. The surface topography was analysed by a stylus pro？lolemeter and 3D image analysis. EDS and FIB were used to characterize the elemental composition and structure ？ower-like nanostructures and endospores.The results obtained in this study indicated that changes in Ra values of 0.1 and 3.5 μm had no signi？cant impact on the biocidal activity of sheet metal and the coating on E. coli, S. epidermidis and B. subtilils. The coating was as effective as the EPA certi？ed sheet metal in the destruction of vegetative cells within 5 minutes. This studyindicates that degradation of B. subtilis endospore begins within 2 hours after exposure to the coating. By day seven, only extensively degraded endospores and nanostructures were visible on the both surfaces. Our results show that thermal spray copper alloy coatings were as effective as certified antimicrobial sheet metal in the destruction of endospores within hours however; the coating was more effective in killing after one week of exposure.