Influence of chlorides and phosphates on the antiadhesive, antibacterial, and electrochemical properties of an electroplated copper-silver alloy

Nicole Ciacotich, Mogens Kilstrup, Per Møller, Lone Gram*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Antimicrobial surfaces such as copper alloys can reduce the spread of pathogenic microorganisms, e.g., in healthcare settings; however, the surface chemistry and thus the antibacterial activity are influenced by environmental parameters such as cleaning and disinfection procedures. Therefore, the purpose of the present study was to assess how copper-complexing compounds (chlorides and phosphates), common to the clinical environment, can affect the surface chemistry and the antiadhesive and antibacterial properties of a newly developed antibacterial copper-silver alloy and the single alloying metals. The authors demonstrated that the antiadhesion efficacy against S. aureus 8325 was the highest when the copper-silver alloy and copper surfaces (four- and two-log bacterial reduction compared to stainless steel controls, respectively) were exposed to chloride-containing suspensions. This was explained by the electrochemical activity of copper that dissolved as Cu+, highly toxic to the bacterial cells, in the presence of Cl- and eventually formed a chlorine- and oxygen-rich layer with the incorporation of phosphorus, if also phosphates were present. If chlorides were omitted from the wet environment, there was no difference (P > 0.05) in bacterial counts on copper-silver alloy, copper, silver, and AISI 316 stainless steel control surfaces, due to the fact that no oxidizing conditions were established and therefore there was no dissolution of copper ions from copper-silver alloy and copper surfaces. However, under dry conditions, copper-silver alloy and pure copper surfaces were antibacterial also in the absence of chlorides, suggesting a marked difference between dry and wet conditions in terms of the interactions between surfaces and bacteria. The authors conclude that an attentive design of control policies integrating disinfection interventions and antimicrobial surfaces, such as the copper-silver alloy coating, can be a beneficial solution in fighting the spread of antibiotic resistant bacterial strains and potentially reducing the number of disease outbreaks.
Original languageEnglish
Article number021005
JournalBiointerphases
Volume14
Issue number2
Number of pages11
ISSN1934-8630
DOIs
Publication statusPublished - 2019

Cite this

@article{2f739d116c084935a26588ccc08abcdc,
title = "Influence of chlorides and phosphates on the antiadhesive, antibacterial, and electrochemical properties of an electroplated copper-silver alloy",
abstract = "Antimicrobial surfaces such as copper alloys can reduce the spread of pathogenic microorganisms, e.g., in healthcare settings; however, the surface chemistry and thus the antibacterial activity are influenced by environmental parameters such as cleaning and disinfection procedures. Therefore, the purpose of the present study was to assess how copper-complexing compounds (chlorides and phosphates), common to the clinical environment, can affect the surface chemistry and the antiadhesive and antibacterial properties of a newly developed antibacterial copper-silver alloy and the single alloying metals. The authors demonstrated that the antiadhesion efficacy against S. aureus 8325 was the highest when the copper-silver alloy and copper surfaces (four- and two-log bacterial reduction compared to stainless steel controls, respectively) were exposed to chloride-containing suspensions. This was explained by the electrochemical activity of copper that dissolved as Cu+, highly toxic to the bacterial cells, in the presence of Cl- and eventually formed a chlorine- and oxygen-rich layer with the incorporation of phosphorus, if also phosphates were present. If chlorides were omitted from the wet environment, there was no difference (P > 0.05) in bacterial counts on copper-silver alloy, copper, silver, and AISI 316 stainless steel control surfaces, due to the fact that no oxidizing conditions were established and therefore there was no dissolution of copper ions from copper-silver alloy and copper surfaces. However, under dry conditions, copper-silver alloy and pure copper surfaces were antibacterial also in the absence of chlorides, suggesting a marked difference between dry and wet conditions in terms of the interactions between surfaces and bacteria. The authors conclude that an attentive design of control policies integrating disinfection interventions and antimicrobial surfaces, such as the copper-silver alloy coating, can be a beneficial solution in fighting the spread of antibiotic resistant bacterial strains and potentially reducing the number of disease outbreaks.",
author = "Nicole Ciacotich and Mogens Kilstrup and Per M{\o}ller and Lone Gram",
year = "2019",
doi = "10.1116/1.5088936",
language = "English",
volume = "14",
journal = "Biointerphases",
issn = "1934-8630",
publisher = "the American Institute of Physics",
number = "2",

}

Influence of chlorides and phosphates on the antiadhesive, antibacterial, and electrochemical properties of an electroplated copper-silver alloy. / Ciacotich, Nicole; Kilstrup, Mogens; Møller, Per; Gram, Lone.

In: Biointerphases, Vol. 14, No. 2, 021005, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Influence of chlorides and phosphates on the antiadhesive, antibacterial, and electrochemical properties of an electroplated copper-silver alloy

AU - Ciacotich, Nicole

AU - Kilstrup, Mogens

AU - Møller, Per

AU - Gram, Lone

PY - 2019

Y1 - 2019

N2 - Antimicrobial surfaces such as copper alloys can reduce the spread of pathogenic microorganisms, e.g., in healthcare settings; however, the surface chemistry and thus the antibacterial activity are influenced by environmental parameters such as cleaning and disinfection procedures. Therefore, the purpose of the present study was to assess how copper-complexing compounds (chlorides and phosphates), common to the clinical environment, can affect the surface chemistry and the antiadhesive and antibacterial properties of a newly developed antibacterial copper-silver alloy and the single alloying metals. The authors demonstrated that the antiadhesion efficacy against S. aureus 8325 was the highest when the copper-silver alloy and copper surfaces (four- and two-log bacterial reduction compared to stainless steel controls, respectively) were exposed to chloride-containing suspensions. This was explained by the electrochemical activity of copper that dissolved as Cu+, highly toxic to the bacterial cells, in the presence of Cl- and eventually formed a chlorine- and oxygen-rich layer with the incorporation of phosphorus, if also phosphates were present. If chlorides were omitted from the wet environment, there was no difference (P > 0.05) in bacterial counts on copper-silver alloy, copper, silver, and AISI 316 stainless steel control surfaces, due to the fact that no oxidizing conditions were established and therefore there was no dissolution of copper ions from copper-silver alloy and copper surfaces. However, under dry conditions, copper-silver alloy and pure copper surfaces were antibacterial also in the absence of chlorides, suggesting a marked difference between dry and wet conditions in terms of the interactions between surfaces and bacteria. The authors conclude that an attentive design of control policies integrating disinfection interventions and antimicrobial surfaces, such as the copper-silver alloy coating, can be a beneficial solution in fighting the spread of antibiotic resistant bacterial strains and potentially reducing the number of disease outbreaks.

AB - Antimicrobial surfaces such as copper alloys can reduce the spread of pathogenic microorganisms, e.g., in healthcare settings; however, the surface chemistry and thus the antibacterial activity are influenced by environmental parameters such as cleaning and disinfection procedures. Therefore, the purpose of the present study was to assess how copper-complexing compounds (chlorides and phosphates), common to the clinical environment, can affect the surface chemistry and the antiadhesive and antibacterial properties of a newly developed antibacterial copper-silver alloy and the single alloying metals. The authors demonstrated that the antiadhesion efficacy against S. aureus 8325 was the highest when the copper-silver alloy and copper surfaces (four- and two-log bacterial reduction compared to stainless steel controls, respectively) were exposed to chloride-containing suspensions. This was explained by the electrochemical activity of copper that dissolved as Cu+, highly toxic to the bacterial cells, in the presence of Cl- and eventually formed a chlorine- and oxygen-rich layer with the incorporation of phosphorus, if also phosphates were present. If chlorides were omitted from the wet environment, there was no difference (P > 0.05) in bacterial counts on copper-silver alloy, copper, silver, and AISI 316 stainless steel control surfaces, due to the fact that no oxidizing conditions were established and therefore there was no dissolution of copper ions from copper-silver alloy and copper surfaces. However, under dry conditions, copper-silver alloy and pure copper surfaces were antibacterial also in the absence of chlorides, suggesting a marked difference between dry and wet conditions in terms of the interactions between surfaces and bacteria. The authors conclude that an attentive design of control policies integrating disinfection interventions and antimicrobial surfaces, such as the copper-silver alloy coating, can be a beneficial solution in fighting the spread of antibiotic resistant bacterial strains and potentially reducing the number of disease outbreaks.

U2 - 10.1116/1.5088936

DO - 10.1116/1.5088936

M3 - Journal article

VL - 14

JO - Biointerphases

JF - Biointerphases

SN - 1934-8630

IS - 2

M1 - 021005

ER -