Abstract No.:
5193

 Scheduled at:
Wednesday, June 07, 2017, Hall 14 10:50 AM
Medical Industry I


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

 Authors:
Larry Pershin* / University of Toronto, Canada
Romina Shafaghi / University of Toronto, Canada
Maurice Ringuette/ University of Toronto, Canada
Javad Mostaghimi/ University of Toronto, Canada

 Abstract:
This study was focused on the biocidal efficacy on spores of copper alloy sheet and thermal spray copper alloy coating at two different surface topographies. Endospores can remain viable in a dormant state for centuries. Our work compares the effectiveness of the thermal spray copper alloy coating and copper alloy sheet in killing endospores.
A twin-wire arc spray system (Sulzer Metco, Westbury, NY, US) was utilized for coating of stainless steel coupons. The feedstock was CuNiZn wire, the coating thickness was 400 µm. The copper alloy C75200 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 profilolemeter and 3D image analysis. EDS and FIB were used to characterize the elemental composition and structure flower-like nanostructures and endospores.
The results obtained in this study indicated that changes in Ra values of 0.1 and 3.5 ¼m had no significant 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 certified sheet metal in the destruction of vegetative cells within 5 minutes.This study indicates that degradation of B. subtilis endospore begins within 2 hours after exposure to the sheet metal or 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.


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