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Antibacterial properties of copper and its alloys

Authors:
  • Sieć Badawcza Łukasiewicz-- Institute of Non-Ferrous Metals

Abstract and Figures

Purpose: The goal of the work is analysis of the knowledge extent on the bactericidal activity of copper and its alloys. Design/methodology/approach: Analysis of publications on the antibacterial properties of copper in the engineering and medical journals, taking also into account publications on the earliest documented employment of copper as the bactericide or medicine. Findings: Analysis of the investigation results presented in more than 350 scientific publications and reports worked out under commission from the Ministry of Health, including 312 scientific publications from the years 1892-1973, indicate to the antimicrobial action of copper and its alloys, which killing bacteria and viruses slows down growth of the microorganisms, and especially of: cobacillus, Legionella pneumophila, Salmonella, Staphylococcus aureus, poliovirus. Research limitations/implications: Application of the acquired research results in hospitals, outpatients’ clinics, and other public medical centres, will make it possible to reduce morbidity resulting from infections, especially of patients after serious medical treatment, operations, or after the complex antibiotic cure which has led them to decline of immunity. Practical implications: Reduction of health care costs is possible in every country by implementation of the acquired investigation results, as a consequence of the decreased treatment costs, by shortening the patients’ stay in a hospital. According to the assessment of the Department of Health of the United Kingdom these savings total to 1 billion pounds a year. Originality/value: Implementation of the analysis of results of investigations on the bactericidal activity of copper and copper based alloys will add to the increase of the patients’ safety level in the public medical centres.
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53
Volume 56
Issue 2
August 2012
Pages 53-60
International Scientific Journal
published monthly by the
World Academy of Materials
and Manufacturing Engineering
© Copyright by International OCSCO World Press. All rights reserved. 2012
Antibacterial properties of copper
and its alloys
J. Konieczny a,*, Z. Rdzawski a,b
a Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland
b Institute of Non-Ferrous Metals, ul. Sowińskiego 5, 44-100 Gliwice, Poland
* Corresponding e-mail address: jaroslaw.konieczny@polsl.pl
Received 19.06.2012; published in revised form 01.08.2012
ABSTRACT
Purpose: The goal of the work is analysis of the knowledge extent on the bactericidal activity of copper
and its alloys.
Design/methodology/approach: Analysis of publications on the antibacterial properties of copper in
the engineering and medical journals, taking also into account publications on the earliest documented
employment of copper as the bactericide or medicine.
Findings: Analysis of the investigation results presented in more than 350 scientific publications and
reports worked out under commission from the Ministry of Health, including 312 scientific publications
from the years 1892-1973, indicate to the antimicrobial action of copper and its alloys, which killing
bacteria and viruses slows down growth of the microorganisms, and especially of: cobacillus, Legionella
pneumophila, Salmonella, Staphylococcus aureus, poliovirus.
Research limitations/implications: Application of the acquired research results in hospitals,
outpatients’ clinics, and other public medical centres, will make it possible to reduce morbidity resulting
from infections, especially of patients after serious medical treatment, operations, or after the complex
antibiotic cure which has led them to decline of immunity.
Practical implications: Reduction of health care costs is possible in every country by implementation
of the acquired investigation results, as a consequence of the decreased treatment costs, by shortening
the patients’ stay in a hospital. According to the assessment of the Department of Health of the United
Kingdom these savings total to 1 billion pounds a year.
Originality/value: Implementation of the analysis of results of investigations on the bactericidal
activity of copper and copper based alloys will add to the increase of the patients’ safety level in the
public medical centres.
Keywords: Metallic alloys; Electron microscopy; Heat treatment; CuTi4 alloy
Reference to this paper should be given in the following way:
J. Konieczny, Z. Rdzawski, Antibacterial properties of copper and its alloys, Archives of Materials
Science and Engineering 56/2 (2012) 53-60.
MATERIALS
1. Introduction
Pure copper and its alloys are characteristic of the unique
mechanical- and physical properties. As early as in 1913 copper
was established a standard for the electrical conductivity. Currently,
copper and its alloys are widely used in many branches of the
modern engineering. The extensive scope of application of pure
copper results from its very good electrical- and thermal
conductivity (being inferior in this respect only to silver), good
1. Introduction
54 54
J. Konieczny, Z. Rdzawski
Archives of Materials Science and Engineering
cold- and hot workability, and high corrosion resistance. Thanks
to these unique properties it finds application in electronics, radio
engineering, and electrical engineering.
Therefore, copper and its alloys enjoy continuous interest
from both scholars and engineers [1-10].
Regrettably, engineers and designers forgot in the last years
about the unique antibacterial properties which are characteristic
of copper, and which were used in the last centuries, in particular,
in places coming often in contact with human skin like, e.g., door
handles.
Copper is one of the first metals which were known to people.
The beginning of smelting, casting, and forging of copper is dated
about 5000 BC, however, smelting of copper from the complex
ores containing arsenic (As) and lead (Pb), is dated 1000 years
later, and obtaining bronze by fusing copper with tin ore and
copper with tin is dated at 2500-2200 BC.
The first recorded cases of using copper as the bactericidal
agent come from the Smith's Papyrus, considered to be the first
and oldest medical document in history of mankind [13], whose
authorship is ascribed to Imhotep, the Egyptian doctor and
architect serving Pharaoh Djoser. It comes from ca. 1700 BC,
however, it is based on texts coming from 3200 BC [14]. Copper
and its compounds were recommended as medicine for "trembling
of the limbs" (this term was used probably for epilepsy), treatment
of burn wounds, skin diseases (itching), and also skin tags on the
neck. Copper in different forms was used for treatment of
diseases: from the metal copper splinters and chips, to naturally
occurring copper salts and oxides. Malachite (Cu2CO3(OH)2) was
used quite often, called by the contemporary the "green pigment"
or chrysocolla (copper silicate), or cupric chloride.
Because of the easy access to copper, it was an important
medicine also in the ancient Greece. It was recommended in the
collection of the Hippocratean works (Corpus Hippocraticum)
assembled probably by the Alexandrian scholars in III century BC
for treatment of ulcerations connected with varices. To prevent
infection of the raw wounds sprinking them was recommended
with a mixture of a dry powder from cupric oxide and copper
sulphate. The antiseptic treatment of wounds was done with
a mixture of honey and the red copper oxide.
The Greek scholar Pedanius Dioscorides gave the recipe in his
book De Materia Medica in the first century AD for obtaining the
green pigment by exposing the metallic copper to the action of the
boiling vinegar vapours. The drug prepared that way was
recommended as remedy of eye ailments, like the bloodshot eyes,
inflammation of eyes, leucoma (white corneal opacity, causing
loss of its transparency), cataract, and „fat in the eyes” (most
probably referring to trachoma – viral infectious disease of
conjunctiva and cornea [15].
Also at the same time the Roman doctor Aulus Cornelius
Celsus, who began practising medicine during the reign of Tiberius
(14 to 37 AD) in his book De Medicina recommended in treatment
of the venereal diseases using a medicine being a mixture of
pepper, myrrh, saffron, and boiled antimony sulphide and cupric
oxide. He recommended for treatment of the nonhealing
ulcerations using the cupric oxide mixed with other components,
including rose oil ensuring the suitable consistency [13].
The cause-and-effect relationship between germs and devel-
opment of a disease was discovered in XVIII century. Only then
the scientists became aware of the antibacterial potential of
copper. Copper is used currently for production of bactericides
and fungicides, oral hygiene products, in the pharmaceutical
industry, and also for applications in the HVAC systems (heating,
ventilation, and air conditioning systems), and also in water
distribution and production of the medical instruments.
Scientific research has confirmed that copper may suppress
the serious pathogens which are the imminent danger to health or
even lives of people. These are, first of all, the methicillin-resistant
Staphylococcus aureus (MRSA), infection with Clostridium difficile
(usually this infection occurs at hospitals, as infections with
Clostridium difficile bacteria are commonly the effect of antibiotics),
Escherichia coli (E.coli, colibacilli), and also legionella pneumophia
(characteristic of Legionellosis). Moreover, copper demonstrates
properties destroying the type A flu viruses. Therefore, it may be
an agent suppressing the danger of the avian flu epidemy.
The importance of counteracting infections in the health
service buildings is testified by the fact that according to the
European Centre for Disease Prevention and Control (ECDC)
about three million of infections connected with health service
leads to about 50,000 demises yearly in Europe. It should be
marked that about 80% of infectious disease are transferred by
touch contact. Among microorganisms which are the reasons for
hospital-acquired infections, the following are named: MRSA,
Escherichia coli, Klebsiella pneumoniae i Clostridium difficile.
Although the hospital-acquired infections may not be avoided, it
was found,basedon investigations, that the number of infections
may be reduced by minimum 15%.
Investigations carried out in the USA, Japan, Great Britain,
and Germany confirmed that copper plays an important role in
deducing the risk of transferring bacteria which imperil people in
the public buildings, hospitals, and food producing institutions.
Prevention of transferring the dangerous bacteria which are
the reason for numerous incidences of diseases has also the
economic aspect. The European Centre for Disease Prevention
and Control has estimated that cure of one case of infection with
Clostridium difficile costs about 5,000-15,000 EUR. If the European
Union is populated by 457 million people, then infections with
Clostridium difficile cost three billion EUR yearly. It is expected
that this amount will double within the next 40 years.
It is estimated that about 80% of the infectious diseases are
transmitted by contact. The equipment used commonly in
hospitals (furniture, medical utensils) is made from aluminium
and stainless steel, which makes an impression of being clean, yet
may be the source of the pathogenic and lethal bacteria and
viruses. The most common infections in hospitals are caused by:
methicillin-resistant Staphylococcus aureus (MRSA), colibacilli,
like Escherichia coli, Klebsiella pneumoniae1, and also
Clostridium difficile2. These germs may cause with the sick
infections of the urinary tract (25%), lower airways (23%),
1 Klebsiella pneumoniae occurring very often in the respiratory-
and alimentary tracts is the reason for pneumonia, infection in
the area of the alimentary tract, bones, joints, or urinary system
(which may lead to sepsis); for infants it is the etiologic factor
for meningitis [16].
2 The bacteria causing necrosis – destruction of the intestine
tissues, ulcerations, secretion of fluids and development of the
inflammatory status, produces toxins: toxin A (enterotoxin) and
toxin B (strong citotoxin), albeit pathogenic may be strains
producing toxin B only.
infections of the surgical wounds (11%), skin infections (10%),
and blood flow disturbances (6%).
Germs causing infections may survive on surface in the
environment of the hospital ward for several days and even
months, where the personnel, patients and also visitors may get in
touch with them. Therefore, items with which people are in
contact, like door handles light switches, trolleys, beds, tables,
bedsidecabinets, handrails, stairs , etc. may be easily made from
copper and its alloys taking advantage of their antibacterial
properties. To be protected optimally from the possibility of
infection in hospitals fabrics should be used containing copper
fibre for production of bed-clothes, coats of patients and clothing
of health service staff.
On 1 cm² of pure copper 10 million Staphylococcus aureus
germs die within 90 minutes. According to [17] yearly cost of
treatment of the hospital-acquired infections in Great Britain,
being incurred because of that by NHS (National Health Service)
is estimated at about 1 billion pounds. Due to infections the
patient's average stay was extended by 11 days andat least 5000
patients die because of complications. It is estimated that
employing the antibacterial properties of copper one may reduce
the number of infections by 15% yearly, which leads to savings of
about 150 million pounds a year [18].
Fig. 1. The current and potential future applications of copper and
its compounds in various areas are based on the biocidal properties
of copper [19]
Examples mentioned above attest to the fact that before the
microorganisms were discovered, the ancient Egyptians, Greeks,
Romans, and the Aztecs used copper to cure, among others, sore
throat and rash, and also used it to maintain the daily hygiene.
Therefore, oddly enough, the antibacterial properties of copper are
the fact hardly known by engineers, especially referring to the
current and potentially future applications taking advantage of
these unique properties (Fig. 1).
2. Material and methods
Copper is the chemical element with the atomic number 29
and electron configuration 1s22s22p63s23p64s13d10, therefore, the
total number of electrons in once Cu atom is 29. However, electrons
with the negative charge on the completely filled orbitals are
much closer to the atomic nucleus with the positive charge than
their equivalents in the incompletely filled orbitals. Therefore, the
completely filled orbitals represent the low energy state, and the
real electron configuration of the copper atom is Ar4s13d10 with
completely populated orbital 3d [20].
Copper is the trace element indispensable in most living
organisms, which occurs in more than types of copper containing
proteins. The most important of them are first of all: lysine
oxidase (protein – in humans LOX gene), which is engaged in
collagen reticulation, tyrosinase, required for synthesis of melanin,
E-hydroxylase dopamine, cytochrome oxidase – the big protein
complex of the mitochondrion and bacteria internal membrane,
and also the superoxide dysmutase required for protection from
the oxidizing damage - consists from the protein part and from the
prosthetic catalytic group in the form of a metal atom playing the
role of the active centre (one of the three types is the cytoplasmic
SOD-1 containing copper (Cu) and zinc (Zn) CuZnSOD-1).
In these enzymes copper plays a role of the donor of
electrons/acceptor by change of the oxidation state from Cu(I) to
Cu(II) in the redox type reaction [21].
The reactive hydroxylic radicals may be generated in the
Fenton's reaction:
Cu+ + H2O2 o Cu2+ + OH- + OH (1)
Very reactive hydroxylic radical may participate in many
reactions harmful for molecules, like oxidation of proteins and
lipides [22]. Copper ions may also lead to depletion of the
sulfhydryl group (it plays two different roles: stabilisation of the
protein particles structure by development of the so called sulphur
bridges, the second one: cell detoxication mechanisms), just like
in cysteine (organic chemical compound counted to the group of
the endogenous coded amino acids, occurs in many proteins).
The molecular mechanisms of the antibacterial activity of
copper result from its atomic structure, and especially from the
structure of its external electronic shell, and also of the possibility
to give (Cu2+) or receive (Cu1+) the electron easily. This is the
reason for many useful copper properties, among others, its
electrochemical properties used in biological systems. Capability
of copper to give or receive the electron is enormous, which
means that it has the high electrochemical potential [23].
Microorganisms are based on enzymes using copper to make
the important life chemical reactions easier. Thanks to the electro-
chemical potential the free copper ion interacts with the bacteria
proteins, which results in suppressing their activity and gives
copper its antibacterial character. One should mention, however,
that the antibacterial mechanism are very complex and are
realised in many ways, both inside of cells and in the intercellular
spaces [23, 24].
Investigation results prove that copper alloys which have the
antibacterial properties may be used in places exposed to human
touch or contact with food and may add to reducing the hazard
connected with transferring the potentially infectious human
pathogens.
55
Antibacterial properties of copper and its alloys
Volume 56 Issue 2 August 2012
cold- and hot workability, and high corrosion resistance. Thanks
to these unique properties it finds application in electronics, radio
engineering, and electrical engineering.
Therefore, copper and its alloys enjoy continuous interest
from both scholars and engineers [1-10].
Regrettably, engineers and designers forgot in the last years
about the unique antibacterial properties which are characteristic
of copper, and which were used in the last centuries, in particular,
in places coming often in contact with human skin like, e.g., door
handles.
Copper is one of the first metals which were known to people.
The beginning of smelting, casting, and forging of copper is dated
about 5000 BC, however, smelting of copper from the complex
ores containing arsenic (As) and lead (Pb), is dated 1000 years
later, and obtaining bronze by fusing copper with tin ore and
copper with tin is dated at 2500-2200 BC.
The first recorded cases of using copper as the bactericidal
agent come from the Smith's Papyrus, considered to be the first
and oldest medical document in history of mankind [13], whose
authorship is ascribed to Imhotep, the Egyptian doctor and
architect serving Pharaoh Djoser. It comes from ca. 1700 BC,
however, it is based on texts coming from 3200 BC [14]. Copper
and its compounds were recommended as medicine for "trembling
of the limbs" (this term was used probably for epilepsy), treatment
of burn wounds, skin diseases (itching), and also skin tags on the
neck. Copper in different forms was used for treatment of
diseases: from the metal copper splinters and chips, to naturally
occurring copper salts and oxides. Malachite (Cu2CO3(OH)2) was
used quite often, called by the contemporary the "green pigment"
or chrysocolla (copper silicate), or cupric chloride.
Because of the easy access to copper, it was an important
medicine also in the ancient Greece. It was recommended in the
collection of the Hippocratean works (Corpus Hippocraticum)
assembled probably by the Alexandrian scholars in III century BC
for treatment of ulcerations connected with varices. To prevent
infection of the raw wounds sprinking them was recommended
with a mixture of a dry powder from cupric oxide and copper
sulphate. The antiseptic treatment of wounds was done with
a mixture of honey and the red copper oxide.
The Greek scholar Pedanius Dioscorides gave the recipe in his
book De Materia Medica in the first century AD for obtaining the
green pigment by exposing the metallic copper to the action of the
boiling vinegar vapours. The drug prepared that way was
recommended as remedy of eye ailments, like the bloodshot eyes,
inflammation of eyes, leucoma (white corneal opacity, causing
loss of its transparency), cataract, and „fat in the eyes” (most
probably referring to trachoma – viral infectious disease of
conjunctiva and cornea [15].
Also at the same time the Roman doctor Aulus Cornelius
Celsus, who began practising medicine during the reign of Tiberius
(14 to 37 AD) in his book De Medicina recommended in treatment
of the venereal diseases using a medicine being a mixture of
pepper, myrrh, saffron, and boiled antimony sulphide and cupric
oxide. He recommended for treatment of the nonhealing
ulcerations using the cupric oxide mixed with other components,
including rose oil ensuring the suitable consistency [13].
The cause-and-effect relationship between germs and devel-
opment of a disease was discovered in XVIII century. Only then
the scientists became aware of the antibacterial potential of
copper. Copper is used currently for production of bactericides
and fungicides, oral hygiene products, in the pharmaceutical
industry, and also for applications in the HVAC systems (heating,
ventilation, and air conditioning systems), and also in water
distribution and production of the medical instruments.
Scientific research has confirmed that copper may suppress
the serious pathogens which are the imminent danger to health or
even lives of people. These are, first of all, the methicillin-resistant
Staphylococcus aureus (MRSA), infection with Clostridium difficile
(usually this infection occurs at hospitals, as infections with
Clostridium difficile bacteria are commonly the effect of antibiotics),
Escherichia coli (E.coli, colibacilli), and also legionella pneumophia
(characteristic of Legionellosis). Moreover, copper demonstrates
properties destroying the type A flu viruses. Therefore, it may be
an agent suppressing the danger of the avian flu epidemy.
The importance of counteracting infections in the health
service buildings is testified by the fact that according to the
European Centre for Disease Prevention and Control (ECDC)
about three million of infections connected with health service
leads to about 50,000 demises yearly in Europe. It should be
marked that about 80% of infectious disease are transferred by
touch contact. Among microorganisms which are the reasons for
hospital-acquired infections, the following are named: MRSA,
Escherichia coli, Klebsiella pneumoniae i Clostridium difficile.
Although the hospital-acquired infections may not be avoided, it
was found,basedon investigations, that the number of infections
may be reduced by minimum 15%.
Investigations carried out in the USA, Japan, Great Britain,
and Germany confirmed that copper plays an important role in
deducing the risk of transferring bacteria which imperil people in
the public buildings, hospitals, and food producing institutions.
Prevention of transferring the dangerous bacteria which are
the reason for numerous incidences of diseases has also the
economic aspect. The European Centre for Disease Prevention
and Control has estimated that cure of one case of infection with
Clostridium difficile costs about 5,000-15,000 EUR. If the European
Union is populated by 457 million people, then infections with
Clostridium difficile cost three billion EUR yearly. It is expected
that this amount will double within the next 40 years.
It is estimated that about 80% of the infectious diseases are
transmitted by contact. The equipment used commonly in
hospitals (furniture, medical utensils) is made from aluminium
and stainless steel, which makes an impression of being clean, yet
may be the source of the pathogenic and lethal bacteria and
viruses. The most common infections in hospitals are caused by:
methicillin-resistant Staphylococcus aureus (MRSA), colibacilli,
like Escherichia coli, Klebsiella pneumoniae1, and also
Clostridium difficile2. These germs may cause with the sick
infections of the urinary tract (25%), lower airways (23%),
1 Klebsiella pneumoniae occurring very often in the respiratory-
and alimentary tracts is the reason for pneumonia, infection in
the area of the alimentary tract, bones, joints, or urinary system
(which may lead to sepsis); for infants it is the etiologic factor
for meningitis [16].
2 The bacteria causing necrosis – destruction of the intestine
tissues, ulcerations, secretion of fluids and development of the
inflammatory status, produces toxins: toxin A (enterotoxin) and
toxin B (strong citotoxin), albeit pathogenic may be strains
producing toxin B only.
infections of the surgical wounds (11%), skin infections (10%),
and blood flow disturbances (6%).
Germs causing infections may survive on surface in the
environment of the hospital ward for several days and even
months, where the personnel, patients and also visitors may get in
touch with them. Therefore, items with which people are in
contact, like door handles light switches, trolleys, beds, tables,
bedsidecabinets, handrails, stairs , etc. may be easily made from
copper and its alloys taking advantage of their antibacterial
properties. To be protected optimally from the possibility of
infection in hospitals fabrics should be used containing copper
fibre for production of bed-clothes, coats of patients and clothing
of health service staff.
On 1 cm² of pure copper 10 million Staphylococcus aureus
germs die within 90 minutes. According to [17] yearly cost of
treatment of the hospital-acquired infections in Great Britain,
being incurred because of that by NHS (National Health Service)
is estimated at about 1 billion pounds. Due to infections the
patient's average stay was extended by 11 days andat least 5000
patients die because of complications. It is estimated that
employing the antibacterial properties of copper one may reduce
the number of infections by 15% yearly, which leads to savings of
about 150 million pounds a year [18].
Fig. 1. The current and potential future applications of copper and
its compounds in various areas are based on the biocidal properties
of copper [19]
Examples mentioned above attest to the fact that before the
microorganisms were discovered, the ancient Egyptians, Greeks,
Romans, and the Aztecs used copper to cure, among others, sore
throat and rash, and also used it to maintain the daily hygiene.
Therefore, oddly enough, the antibacterial properties of copper are
the fact hardly known by engineers, especially referring to the
current and potentially future applications taking advantage of
these unique properties (Fig. 1).
2. Material and methods
Copper is the chemical element with the atomic number 29
and electron configuration 1s22s22p63s23p64s13d10, therefore, the
total number of electrons in once Cu atom is 29. However, electrons
with the negative charge on the completely filled orbitals are
much closer to the atomic nucleus with the positive charge than
their equivalents in the incompletely filled orbitals. Therefore, the
completely filled orbitals represent the low energy state, and the
real electron configuration of the copper atom is Ar4s13d10 with
completely populated orbital 3d [20].
Copper is the trace element indispensable in most living
organisms, which occurs in more than types of copper containing
proteins. The most important of them are first of all: lysine
oxidase (protein – in humans LOX gene), which is engaged in
collagen reticulation, tyrosinase, required for synthesis of melanin,
E-hydroxylase dopamine, cytochrome oxidase – the big protein
complex of the mitochondrion and bacteria internal membrane,
and also the superoxide dysmutase required for protection from
the oxidizing damage - consists from the protein part and from the
prosthetic catalytic group in the form of a metal atom playing the
role of the active centre (one of the three types is the cytoplasmic
SOD-1 containing copper (Cu) and zinc (Zn) CuZnSOD-1).
In these enzymes copper plays a role of the donor of
electrons/acceptor by change of the oxidation state from Cu(I) to
Cu(II) in the redox type reaction [21].
The reactive hydroxylic radicals may be generated in the
Fenton's reaction:
Cu+ + H2O2 o Cu2+ + OH- + OH (1)
Very reactive hydroxylic radical may participate in many
reactions harmful for molecules, like oxidation of proteins and
lipides [22]. Copper ions may also lead to depletion of the
sulfhydryl group (it plays two different roles: stabilisation of the
protein particles structure by development of the so called sulphur
bridges, the second one: cell detoxication mechanisms), just like
in cysteine (organic chemical compound counted to the group of
the endogenous coded amino acids, occurs in many proteins).
The molecular mechanisms of the antibacterial activity of
copper result from its atomic structure, and especially from the
structure of its external electronic shell, and also of the possibility
to give (Cu2+) or receive (Cu1+) the electron easily. This is the
reason for many useful copper properties, among others, its
electrochemical properties used in biological systems. Capability
of copper to give or receive the electron is enormous, which
means that it has the high electrochemical potential [23].
Microorganisms are based on enzymes using copper to make
the important life chemical reactions easier. Thanks to the electro-
chemical potential the free copper ion interacts with the bacteria
proteins, which results in suppressing their activity and gives
copper its antibacterial character. One should mention, however,
that the antibacterial mechanism are very complex and are
realised in many ways, both inside of cells and in the intercellular
spaces [23, 24].
Investigation results prove that copper alloys which have the
antibacterial properties may be used in places exposed to human
touch or contact with food and may add to reducing the hazard
connected with transferring the potentially infectious human
pathogens.
2. Material and methods
56 56
J. Konieczny, Z. Rdzawski
Archives of Materials Science and Engineering
Keevil with associates [25] demonstrated that copper may be
successfully used to control Clostridium difficile bacterium
which causes epidemic of the hospital diarrhoea, especially with
the elderly people, weakened and patients treated with antibiotics
before. However, investigation on the effect of copper on
Clostridium difficile are still ongoing.
Copper may also play an important role in fight with the avian
flu epidemic. The latest Keevil's results [25] indicate that copper
may feature the effective barrier against spread of the avian flu.
After exposure of 2 million active H5N1 virus units on the sheet
copper, its number was reduced after six hours by 99.9%. This
effect is connected with the fact that copper violates integrity of
viruses.
In this aspect the particular use of copper and its alloys results
from their bactericidal properties [23, 26-28]. In 2003 Wilks and
Keevin published [29] the bactericidal research results for 28
different alloys, among which 7 were the copper alloys. It was
found that the inactivation indices of the Listeria monocytogenes
bacterium3 were much higher on copper alloys (Fig. 2). As an
example, the alloy called new silver (65% Cu, 18% Ni, 17 Zn)
inactivated all bacteria after 90 minutes. Further research of Noyce
and Keevil proved beyond doubt that copper may suppress devel-
opment of the methicillin-resistant Staphylococcus aureus (MRSA)
called the "superbacterium" (Fig. 3) being immune in fact to all
E-lactam antibiotics (penicillins, ampicillins, cephalosporins).
Also investigations made with the colibaccili demonstrated
unambiguously that copper alloys feature an important barrier for
spread of the bacterium [30].
Fig. 2. Life span of Listeria monocytogenes bacteria on selected
copper alloys and stainless steel at ambient temperature
Therefore, copper alloys are used in production, of, among
others, sanitary installation tubes, fittings, door handles, knobs
and handrails, and as a material for production of hospital
equipment and utensils [23].
3 A bacterium, very dangerous for humans, infection Listeria
monocytogenes, causes listeriosis, whose symptoms are most
often: septicaemia, spinal meningitis, encephalitis, corneal ulcer,
and pneumonia, and also may be the reason for miscarriages or
fatal death [31-34].
Fig. 3 presents the life span of Staphylococcus aureus on
various substrates. The investigation results show that bacteria
survival rate decreases along with the growth of copper content in
substrate material. For C19700 (99% Cu) alloy the survival rate is
reduced to 1.5 h; for C24000 (80% Cu) alloy the significant
reduction of the survival rate occurs after 3 hours and the
complete lack of survival capacity after 4.5 hours, and on C77000
(55% Cu) alloy Staphylococcus aureus has significant and lasting
reduction of survival rate after 4.5 hours. However, the survival
rate on stainless steel was as long as up to 72 hours [23].
Fig. 3. Survival rate of the methicillin-resistant Staphylococcus
aureus (MRSA) on three copper alloys: C19700 (99% Cu), C24000
(80% Cu), C77000 (55% Cu) and stainless steel (S304) at room
temperature [30]
Time 0 Time 24h
Fig. 4. Behaviour of the bacterial colony from Escherichia coli strain
after 24 h contact on Petri dishes containing copper and PCV [35]
Results of the many scientific research projects (312 publi-
cations from 1892-1973 period) indicate the antimicrobial copper
activity which suppresses development of microorganisms, and
especially of:
x Escherichia Coli [23] – cobacillus (Fig. 4),
x Legionella Pneumophilaand bacterial flora occurring in the
water environment [36] are the cases of Legionellosis – a group
of the respiratory system diseases, first of all – pneumonia,
x Actinomuicor elegans [37],
x Bacterium linens [37],
x Tuorolopsis utilis [38],
x Acromobacter Fischeri, Photobacterium Phosphoreum [39],
x Mercenaria mercenaria [40],
PCV Cu PCV Cu
x Polio virus [41],
x Paramecium Caudatum [42],
x Compylobacter jejuni [43],
x Salmonella Entrica [43], is pathogenic both for the humans
and for the animals - causing the acute food poisonings. They
can live outside of a living organism for several months in
propitious conditions (warm, humid, presence of protein).
Currently, the antibacterial activity of copper is explained with
three mechanisms:
x increased concentration of copper inside the cell causes
oxidizing stress (the condition of a lack of equilibrium
between activity of the reactive forms of oxygen and the
biological capability to quick detoxication of the reactive by-
products or repair of damage made) and generation of the
hydrogen peroxide; in these conditions copper takes part in
the so called Fenton's reaction4 – chemical reaction causes
oxidizing damages of cells;
x excess of copper causes decrease of the membrane integrity of
microorganisms, which leads to leak of the particular cell
nutritional elements, like potassium and glutamate, which
leads to desiccation, and next to the cell death;
x albeit copper is required for many functions, occurring in
proteins, however, copper in excesscombines with proteins
which do not require its presence for their functioning. This
„improper” bonding leads to atrophy of protein functions and/
or decay of proteins to the dysfunctional components.
The examples above demonstrate that copper suppresses
reproduction of bacteria. It is, therefore, the very good material,
e.g., in housing industry. Plastics, albeit much cheaper than copper,
are the environment propitious to reproduction of pathogens.
Results of the investigations carried out revealed that on
surfaces of copper alloys (with mass concentration of min 65% Cu)
as much as 99.9% of bacteria were destroyed already after 2 hours
of exposure. Therefore, is made clear that copper is the ideal
material for the bactericidal surfaces not only in health service
and public spaces, but also, for example, in the food industry.
In [44] the antibacterial susceptibility constants were defined
and specified and used for assessment of the antibacterial properties
of nanoparticles of silver and copper in respect to Escherichia coli
and Bacillus subtilis bacteria. Constant Z (mL/µg) defining
susceptibility of nanoparticles is calculated using the relationship:
C
N
N
Z
¸
¸
¹
·
¨
¨
©
§
0
ln
(2)
where:
N – units forming the bacterial colony (CFUs) on agar dish
containing nanoparticles (Ag or Cu),
N0 – CFU on pure agar dish,
C – concentration of nanoparticles (µg/mL).
It turns out from equation (2) that the higher Z value
demonstrates the higher susceptibility of bacteria to nanoparticles
of metals, which suggests that nanoparticles are more effective
fighting the bacteria.
4 Fenton's reaction takes place with ions of the transition metals
(Cu+ lub Fe2+), resulting with the most reactive oxygen forms.
Reaction of copper nanoparticles with the particle size of
100 nm with Bacillus subtilis bacterium revealed the highest
susceptibility (Z=0.0734 ml/µg), whereas the reaction with silver
nanoparticles with the size of 40 nm with Escherichia coli
bacterium revealed lower susceptibility (Z=0.0236 ml/µg).
However, the authors indicate that the size of nanoparticles may
influence their antibacterial activity, therefore further investigations
have to be carried out, which results will make it possible to
determine the effect of the size of nanoparticles on their
antibacterial susceptibility (Figs. 5 and 6).
Fig. 5. Antibacterial results of silver nanoparticles [44]
Fig. 6. Antibacterial results of copper nanoparticles [44]
Next, in [45] investigations were made of growth of various
strains of microorganisms in presence of copper and silver
nanoparticles, determining their effect on the growth profile.
It was demonstrated that nanoparticles of silver and copper are
very good antibacterial agents against Escherichia coli, Bacillus
subtilis and Staphylococcus aureus bacteria. Investigation results
of MIC (Minimum Inhibitory Concentration), MBC (Minimum
57
Antibacterial properties of copper and its alloys
Volume 56 Issue 2 August 2012
Keevil with associates [25] demonstrated that copper may be
successfully used to control Clostridium difficile bacterium
which causes epidemic of the hospital diarrhoea, especially with
the elderly people, weakened and patients treated with antibiotics
before. However, investigation on the effect of copper on
Clostridium difficile are still ongoing.
Copper may also play an important role in fight with the avian
flu epidemic. The latest Keevil's results [25] indicate that copper
may feature the effective barrier against spread of the avian flu.
After exposure of 2 million active H5N1 virus units on the sheet
copper, its number was reduced after six hours by 99.9%. This
effect is connected with the fact that copper violates integrity of
viruses.
In this aspect the particular use of copper and its alloys results
from their bactericidal properties [23, 26-28]. In 2003 Wilks and
Keevin published [29] the bactericidal research results for 28
different alloys, among which 7 were the copper alloys. It was
found that the inactivation indices of the Listeria monocytogenes
bacterium3 were much higher on copper alloys (Fig. 2). As an
example, the alloy called new silver (65% Cu, 18% Ni, 17 Zn)
inactivated all bacteria after 90 minutes. Further research of Noyce
and Keevil proved beyond doubt that copper may suppress devel-
opment of the methicillin-resistant Staphylococcus aureus (MRSA)
called the "superbacterium" (Fig. 3) being immune in fact to all
E-lactam antibiotics (penicillins, ampicillins, cephalosporins).
Also investigations made with the colibaccili demonstrated
unambiguously that copper alloys feature an important barrier for
spread of the bacterium [30].
Fig. 2. Life span of Listeria monocytogenes bacteria on selected
copper alloys and stainless steel at ambient temperature
Therefore, copper alloys are used in production, of, among
others, sanitary installation tubes, fittings, door handles, knobs
and handrails, and as a material for production of hospital
equipment and utensils [23].
3 A bacterium, very dangerous for humans, infection Listeria
monocytogenes, causes listeriosis, whose symptoms are most
often: septicaemia, spinal meningitis, encephalitis, corneal ulcer,
and pneumonia, and also may be the reason for miscarriages or
fatal death [31-34].
Fig. 3 presents the life span of Staphylococcus aureus on
various substrates. The investigation results show that bacteria
survival rate decreases along with the growth of copper content in
substrate material. For C19700 (99% Cu) alloy the survival rate is
reduced to 1.5 h; for C24000 (80% Cu) alloy the significant
reduction of the survival rate occurs after 3 hours and the
complete lack of survival capacity after 4.5 hours, and on C77000
(55% Cu) alloy Staphylococcus aureus has significant and lasting
reduction of survival rate after 4.5 hours. However, the survival
rate on stainless steel was as long as up to 72 hours [23].
Fig. 3. Survival rate of the methicillin-resistant Staphylococcus
aureus (MRSA) on three copper alloys: C19700 (99% Cu), C24000
(80% Cu), C77000 (55% Cu) and stainless steel (S304) at room
temperature [30]
Time 0 Time 24h
Fig. 4. Behaviour of the bacterial colony from Escherichia coli strain
after 24 h contact on Petri dishes containing copper and PCV [35]
Results of the many scientific research projects (312 publi-
cations from 1892-1973 period) indicate the antimicrobial copper
activity which suppresses development of microorganisms, and
especially of:
x Escherichia Coli [23] – cobacillus (Fig. 4),
x Legionella Pneumophilaand bacterial flora occurring in the
water environment [36] are the cases of Legionellosis – a group
of the respiratory system diseases, first of all – pneumonia,
x Actinomuicor elegans [37],
x Bacterium linens [37],
x Tuorolopsis utilis [38],
x Acromobacter Fischeri, Photobacterium Phosphoreum [39],
x Mercenaria mercenaria [40],
PCV Cu PCV Cu
x Polio virus [41],
x Paramecium Caudatum [42],
x Compylobacter jejuni [43],
x Salmonella Entrica [43], is pathogenic both for the humans
and for the animals - causing the acute food poisonings. They
can live outside of a living organism for several months in
propitious conditions (warm, humid, presence of protein).
Currently, the antibacterial activity of copper is explained with
three mechanisms:
x increased concentration of copper inside the cell causes
oxidizing stress (the condition of a lack of equilibrium
between activity of the reactive forms of oxygen and the
biological capability to quick detoxication of the reactive by-
products or repair of damage made) and generation of the
hydrogen peroxide; in these conditions copper takes part in
the so called Fenton's reaction4 – chemical reaction causes
oxidizing damages of cells;
x excess of copper causes decrease of the membrane integrity of
microorganisms, which leads to leak of the particular cell
nutritional elements, like potassium and glutamate, which
leads to desiccation, and next to the cell death;
x albeit copper is required for many functions, occurring in
proteins, however, copper in excesscombines with proteins
which do not require its presence for their functioning. This
„improper” bonding leads to atrophy of protein functions and/
or decay of proteins to the dysfunctional components.
The examples above demonstrate that copper suppresses
reproduction of bacteria. It is, therefore, the very good material,
e.g., in housing industry. Plastics, albeit much cheaper than copper,
are the environment propitious to reproduction of pathogens.
Results of the investigations carried out revealed that on
surfaces of copper alloys (with mass concentration of min 65% Cu)
as much as 99.9% of bacteria were destroyed already after 2 hours
of exposure. Therefore, is made clear that copper is the ideal
material for the bactericidal surfaces not only in health service
and public spaces, but also, for example, in the food industry.
In [44] the antibacterial susceptibility constants were defined
and specified and used for assessment of the antibacterial properties
of nanoparticles of silver and copper in respect to Escherichia coli
and Bacillus subtilis bacteria. Constant Z (mL/µg) defining
susceptibility of nanoparticles is calculated using the relationship:
C
N
N
Z
¸
¸
¹
·
¨
¨
©
§
0
ln
(2)
where:
N – units forming the bacterial colony (CFUs) on agar dish
containing nanoparticles (Ag or Cu),
N0 – CFU on pure agar dish,
C – concentration of nanoparticles (µg/mL).
It turns out from equation (2) that the higher Z value
demonstrates the higher susceptibility of bacteria to nanoparticles
of metals, which suggests that nanoparticles are more effective
fighting the bacteria.
4 Fenton's reaction takes place with ions of the transition metals
(Cu+ lub Fe2+), resulting with the most reactive oxygen forms.
Reaction of copper nanoparticles with the particle size of
100 nm with Bacillus subtilis bacterium revealed the highest
susceptibility (Z=0.0734 ml/µg), whereas the reaction with silver
nanoparticles with the size of 40 nm with Escherichia coli
bacterium revealed lower susceptibility (Z=0.0236 ml/µg).
However, the authors indicate that the size of nanoparticles may
influence their antibacterial activity, therefore further investigations
have to be carried out, which results will make it possible to
determine the effect of the size of nanoparticles on their
antibacterial susceptibility (Figs. 5 and 6).
Fig. 5. Antibacterial results of silver nanoparticles [44]
Fig. 6. Antibacterial results of copper nanoparticles [44]
Next, in [45] investigations were made of growth of various
strains of microorganisms in presence of copper and silver
nanoparticles, determining their effect on the growth profile.
It was demonstrated that nanoparticles of silver and copper are
very good antibacterial agents against Escherichia coli, Bacillus
subtilis and Staphylococcus aureus bacteria. Investigation results
of MIC (Minimum Inhibitory Concentration), MBC (Minimum
58 58
J. Konieczny, Z. Rdzawski
Archives of Materials Science and Engineering
Bactericidal Concentration) and diffusion test suggest that for all
strains of Escherichia coli and Staphylococcus aureus bacteria,
the antibacterial activity of silver nanoparticles is more effective
and copper nanoparticles are more effective fighting Bacillus
subtilisbacterium. Based on that, the authors assumed that copper
nanoparticles have bigger affinity to the active surface of bacterium
from Bacillus subtilis group, which might cause the more effective
bactericidal activity. The authors suggest that, albeit the activity
mechanisms are still not fully known for the copper and silver
nanoparticles, yet their merging may lead to the more complete
bactericidal activity against the mixed population of bacteria.
In another experiment [46] the bactericidal activity was
compared of equipment items in the hospital ward made from
copper, with which people have contact (most often by skin
touch). This pertained to, among others, sets of handles and taps
at the washing basins, metal plates (mounted vertically on the
door) for opening the door to the hospital ward. Samples were
taken from each element for testing presence of bacteria and
presence of bacteria were compared on the same elements in the
ward, which did not contain copper. It turned out that the drop of
the average number of microorganisms present on copper surfaces
exceeded 90%.
One of the most severe disease risks in HVAC systems is
legionella pneumophila bacterium causing Legionellosis [36]
(Legionnaire's disease, Pontiac fever), moulds like Aspergillus
Flavus, parasite which, thanks to production of aflatoxin, one of
the strongest poisons known, destroys human health, and fungi
like Aspergillus niger. Use of copper and its alloys install to
biologically neutral materials in the central heating systems, heat
transfer installations, A/C installations, filters, or sewage tubes
makes control possible of the amount of bacteria, fungi, and
moulds in the dark and humid elements of the HVAC system.
It may also turn out to be an effective protection agent because of
the economic reasons.
Fig. 7. Schema describing the first stages of destroying the bacteria
cells: (A) copper dissolves on surface and causes damages pene-
trating in the bacteria cells; (B) breakages of cell membrane, due
to stresses caused by copper atoms and other phenomena leading
to loss of membrane potential and cytoplasmic contents (C) copper
ions stimulate development of reactive oxygen forms which causes
further damages of cells; (D) genome and plasmid DNA is subject
to degradation [47]
Silver cations are more toxic for bacteria than copper cations
[48]. However, silver is unstable at the oxidation state Ag(II) and
should not catalyse w the Fenton type reactions. It was found, as
a result of investigations carried out by Mikolay and associates
[49] that silversurfaces do not kill bacteria. However, it was
confirmed that copper alloys were really much more bactericidal
than materials containing silver. Examinations were made at the
temperature and humidity typical for the closed spaces like those
that occur, e.g., in hospitals.
Mikolay [49] proved also that bacteria whose genes are coded
with copper cations, like, e.g. Pseudomonas aeruginosa died very
quickly on copper surface just like E. coli bacterium. Thus it was
confirmed that copper cations released form the copped surfaces
were responsible for the bacteria annihilation process (Fig. 7).
3. Conclusions
Nowadays, in the modern building engineering the risk of
exposing people to the toxic activity of microorganisms forced
improvement of the hygienic conditions in the air conditioning,
ventilation and heating (HVAC) systems.
On the other hand, there is a possibility, making use of the
physical properties of copper (thermal conductivity), to increase
the power effectiveness of systems in which it is installed, and
also the mechanical one (operation at the elevated temperature),
there is a possibility to fight bacteria and other pathogenic
organisms using high temperature of media required in the
thermal disinfection process.
Usually the potable water is free from the pathogenic
organisms, however, in the public potable water systems presence
of viruses, bacteria, fungi, and parasites is possible. Therefore,
using copper may also help in fighting the pathogenic organisms
in the potable water. Copper sanitary pipes may ensure in this
case the additional protection from presence of these organisms
and reduce the disease risk.
Currently copper is used in the entire pharmaceutical branch
of business, beginning from the antiseptic and antifungal products
for health protection, and also for production of personal hygiene
items, e.g., creams containing the trace elements.
In the USA, the Environmental Protection Agency, approved
copper in March 2008 as an antibacterial agent which fights the
particular bacteria causing the potentially lethal infections. As an
effect of the investigations carried out on a large scale in the USA,
275 copper alloys were awarded the mark of the "antibacterial
materials" in the US. Copper and its alloys are the first solid
materials which have acquired such status. So far, the register of
the sanitary and disinfecting means included only liquid substances
(or sprays) and gas materials.
References
[1] J. Konieczny, Z. Rdzawski, J. Stobrawa, W. Gáuchowski,
Hardness and electrical conductivity of cold rolled and aged
CuTi4 alloy, Proceedings of the VIII Ukraine-Poland
Conference of Young Scientists "Mechanics and Computer
Science", Chmielnicki, Ukraine, 2011(in print).
[2] Z. Rdzawski, W. Gáuchowski, J. Konieczny, Microstructure
and properties of CuTi4 alloy, Proceedings of the 13th
International Symposium IMSP’2010, Panukkale University,
Denizli, Turkey, 2010, 955-962.
[3] J. Konieczny, Z. Rdzawski, Misorientation in rolled CuTi4
alloy, Archives of Materials Science and Engineering 52/1
(2011) 5-12.
[4] Z. Rdzawski, J. Stobrawa, W. Gáuchowski, J. Konieczny,
Thermomechanical processing of CuTi4 alloy, Journal of
Achievements in Materials and Manufacturing Engineering
42 (2010) 9-25.
[5] W. Ozgowicz, E. Kalinowska-Ozgowicz, B. Grzegorczyk,
Thermomechanical treatment of low-alloy copper alloys of
the kind CuCo2Be and CuCo1NiBe, Journal of Achievements
in Materials and Manufacturing Engineering 46/2 (2011)
161-168.
[6] W. Ozgowicz, E. Kalinowska-Ozgowicz, B. Grzegorczyk,
The influence of the temperature of tensile test on the
structure and plastic properties of copper alloy type CuCr1Zr,
Journal of Achievements in Materials and Manufacturing
Engineering 29/2 (2008) 123-136.
[7] W. Gáuchowski, J.P. Stobrawa, Z.M. Rdzawski, K. Mar-
szowski, Microstructural characterization of high strength
high conductivity Cu-Nb microcomposite wires, Journal of
Achievements in Materials and Manufacturing Engineering
46/1 (2011) 40-49.
[8] W. Ozgowicz, E. Kalinowska-Ozgowicz, B. Grzegorczyk,
The microstructure and mechanical properties of the alloy
CuZn30 after recrystallizion annealing, Journal of Achieve-
ments in Materials and Manufacturing Engineering 40/1
(2010) 15-24.
[9] B. LeszczyĔska-Madej, M. Richert, Microstructure and
properties of dynamically compressed copper Cu99.99,
Journal of Achievements in Materials and Manufacturing
Engineering 39/1 (2010) 35-42.
[10] J.P. Stobrawa, Z.M. Rdzawski, W. Gáuchowski, W. Malec,
Microstructure evolution in CRCS processed strips of
CuCr0,6 alloy, Journal of Achievements in Materials and
Manufacturing Engineering 38/2 (2010) 195-202.
[11] J. Konieczny, à. Kondzioáka. I. Máodkowska-Przepiórowska,
The investigation of microstructure and hardness of
archaeological alloys, Journal of Achievements in Materials
and Manufacturing Engineering 49/2 (2011) 166-179.
[12] K. SĊkowski, The origins of copper alloy casting,
Proceedings of the Scientific Conference "Modern trends in
non-ferrous metal foundry”, Foundry Research Institute,
Cracow, 1997, 73.
[13] H.H.A. Dollwet, J.R.J. Sorenson, Historic uses of copper
compounds in medicine, Trace Elements in Medicine 2/2
(1985) 80-87.
[14] R. ĩukiel, S. Nowak, R. Jankowski, R. Piestrzeniewicz,
Historical neurosurogical casuistic. Part I., Neuroskop 8
(2006) 9-15.
[15] M. Collins, Medieval Herbals: The Illustrative Traditions,
The British Library and University of Toronto Press,
London, 2000.
[16] M.L. Zaremba, J. Borowski, Medical microbiology, Third
Edition, PZWL, Warsaw, 2004 (in Polish).
[17] The Management and Control of Hospital Acquired Infection
in Acute NHS Trusts in England, National Audit Office,
London, 2000.
[18] J.O. Noyce, H. Michels, C.W. Keevil, Inactivation of Influenza
A virus on Copper versus Stainless Steel Surfaces, Applied
and Environmental Microbiology 73/8 (2007) 2748-2750.
[19] G. Borkow, J. Gabbay, Copper, An Ancient Remedy
Returning to Fight Microbial, Fungal and Viral Infections,
Current Chemical Biology 3 (2009) 272-278.
[20] C.E. Housecroft, E.C. Constable, Chemistry, Third Edition,
Pearson Education Limited, Essex, 2006.
[21] K.D. Karlin, Metalloenzymes, structural motifs, and inorganic
models, Science 261 (1993) 701-708.
[22] Y. Yoshida, S. Furuta, E. Niki, Effects of metal chelating
agents on the oxidation of lipids induced by copper and iron,
Biochimica et Biophysica Acta (BBA) – Lipids and Lipid
Metabolism 1210/1 (1993) 81-88.
[23] A. Lewis, C.W. Keevil, Antibacterial properties of alloys
and its alloys in HVAC&R systems, International Copper
Association, New York, 2004.
[24] R.B. Thurman, C.P. Gerba, The Molecular Mechanisms of
Copper and Silver Ion Disinfection of Bacteria and Viruses,
CRC Critical Reviews in Environmental Control 18/4 (1989)
295-315.
[25] J.O. Noyce, H. Michels, C.W. Keevil, Inactivation of
Influenza A virus on Copper versus Stainless Steel Surfaces,
Applied and Environmental Microbiology 73/8 (2007) 2748-
2750.
[26] A. Ciszewski, T. Radomski, A. Szummer, Materials Science,
Warsaw University of Technology Publishing House,
Warsaw, 2003.
[27] S.A. Wilks, H. Michels, C.W. Keevil, The survival of
Escherichia coli O157 on a range of metal surfaces,
International Journal of Food Microbiology 105/3 (2005)
445-454.
[28] H. Kawakami, K. Yoshida, Y. Nishida, Y. Kikuchi, Y. Sato,
Antibacterial properties of metallic elements for alloying
evaluated with application of JIS, ISIJ International 48/9
(2008) 1299-1304.
[29] S.A. Wilks, H.T. Michels, C.W. Keevil, Survival of Listeria
monocytogenes Scott A on metal surfaces: Implications for
cross-contamination, International Journal of Food Micro-
biology 111/2 (2006) 93-98.
[30] H.T. Michels, S.A. Wilks, J.O. Noyce, C.W. Keevil, Copper
Alloys for Human Infectious Disease Control, Proceedings
of the Materials Science and Technology Conference,
Pittsburgh, 2005.
[31] M.L. Gray, A.H. Killinger, Listeria monocytogenes and
listeric infection, Bacteriology Review 30/2 (1966) 309-382.
[32] R.W. Armstrong, P.C. Fung, Brainstem encephalitis
(Rhombencephalitis) due to Listeria monocytogenes: case
report and review, Clinical Infectious Diseases 16/5 (1993)
689-702.
[33] S. Holland, E. Alfonso, D. Gelender, D. Heidegger,
A. Mendelsohn, S. Ullman, D. Miller, Corneal ulcer due to
Listeria monocytogenes, Cornea 6 (1987) 144-146.
[34] L. Whitelock-Jones, J. Carswell, K.C. Rassmussen, Listeria
pneumonia. A case report, South African Medical Journal 75
(1989) 88-189.
[35] The Polish Copper Promotion Centre (http://miedz.org.pl/).
[36] D. Schoenen, G. Schlomer, Microbial contamination of
water by pipe and tube materials. 3. Behaviour of
Escherichia coli, Citrobacter freundii and Klebsiella
pneumoniae. Zentralbl Hyg Umweltmed 188 (1989) 475-
480 (in German).
[37] S.M. Chang, M. Tien, Effects of Heavy Metal Ions on the
Growth of Microorganisms, Bull. Inst. Chem., Adad. Sinica
16 (1969) 29-39.
References
3. Conclusions
59
Antibacterial properties of copper and its alloys
Volume 56 Issue 2 August 2012
Bactericidal Concentration) and diffusion test suggest that for all
strains of Escherichia coli and Staphylococcus aureus bacteria,
the antibacterial activity of silver nanoparticles is more effective
and copper nanoparticles are more effective fighting Bacillus
subtilisbacterium. Based on that, the authors assumed that copper
nanoparticles have bigger affinity to the active surface of bacterium
from Bacillus subtilis group, which might cause the more effective
bactericidal activity. The authors suggest that, albeit the activity
mechanisms are still not fully known for the copper and silver
nanoparticles, yet their merging may lead to the more complete
bactericidal activity against the mixed population of bacteria.
In another experiment [46] the bactericidal activity was
compared of equipment items in the hospital ward made from
copper, with which people have contact (most often by skin
touch). This pertained to, among others, sets of handles and taps
at the washing basins, metal plates (mounted vertically on the
door) for opening the door to the hospital ward. Samples were
taken from each element for testing presence of bacteria and
presence of bacteria were compared on the same elements in the
ward, which did not contain copper. It turned out that the drop of
the average number of microorganisms present on copper surfaces
exceeded 90%.
One of the most severe disease risks in HVAC systems is
legionella pneumophila bacterium causing Legionellosis [36]
(Legionnaire's disease, Pontiac fever), moulds like Aspergillus
Flavus, parasite which, thanks to production of aflatoxin, one of
the strongest poisons known, destroys human health, and fungi
like Aspergillus niger. Use of copper and its alloys install to
biologically neutral materials in the central heating systems, heat
transfer installations, A/C installations, filters, or sewage tubes
makes control possible of the amount of bacteria, fungi, and
moulds in the dark and humid elements of the HVAC system.
It may also turn out to be an effective protection agent because of
the economic reasons.
Fig. 7. Schema describing the first stages of destroying the bacteria
cells: (A) copper dissolves on surface and causes damages pene-
trating in the bacteria cells; (B) breakages of cell membrane, due
to stresses caused by copper atoms and other phenomena leading
to loss of membrane potential and cytoplasmic contents (C) copper
ions stimulate development of reactive oxygen forms which causes
further damages of cells; (D) genome and plasmid DNA is subject
to degradation [47]
Silver cations are more toxic for bacteria than copper cations
[48]. However, silver is unstable at the oxidation state Ag(II) and
should not catalyse w the Fenton type reactions. It was found, as
a result of investigations carried out by Mikolay and associates
[49] that silversurfaces do not kill bacteria. However, it was
confirmed that copper alloys were really much more bactericidal
than materials containing silver. Examinations were made at the
temperature and humidity typical for the closed spaces like those
that occur, e.g., in hospitals.
Mikolay [49] proved also that bacteria whose genes are coded
with copper cations, like, e.g. Pseudomonas aeruginosa died very
quickly on copper surface just like E. coli bacterium. Thus it was
confirmed that copper cations released form the copped surfaces
were responsible for the bacteria annihilation process (Fig. 7).
3. Conclusions
Nowadays, in the modern building engineering the risk of
exposing people to the toxic activity of microorganisms forced
improvement of the hygienic conditions in the air conditioning,
ventilation and heating (HVAC) systems.
On the other hand, there is a possibility, making use of the
physical properties of copper (thermal conductivity), to increase
the power effectiveness of systems in which it is installed, and
also the mechanical one (operation at the elevated temperature),
there is a possibility to fight bacteria and other pathogenic
organisms using high temperature of media required in the
thermal disinfection process.
Usually the potable water is free from the pathogenic
organisms, however, in the public potable water systems presence
of viruses, bacteria, fungi, and parasites is possible. Therefore,
using copper may also help in fighting the pathogenic organisms
in the potable water. Copper sanitary pipes may ensure in this
case the additional protection from presence of these organisms
and reduce the disease risk.
Currently copper is used in the entire pharmaceutical branch
of business, beginning from the antiseptic and antifungal products
for health protection, and also for production of personal hygiene
items, e.g., creams containing the trace elements.
In the USA, the Environmental Protection Agency, approved
copper in March 2008 as an antibacterial agent which fights the
particular bacteria causing the potentially lethal infections. As an
effect of the investigations carried out on a large scale in the USA,
275 copper alloys were awarded the mark of the "antibacterial
materials" in the US. Copper and its alloys are the first solid
materials which have acquired such status. So far, the register of
the sanitary and disinfecting means included only liquid substances
(or sprays) and gas materials.
References
[1] J. Konieczny, Z. Rdzawski, J. Stobrawa, W. Gáuchowski,
Hardness and electrical conductivity of cold rolled and aged
CuTi4 alloy, Proceedings of the VIII Ukraine-Poland
Conference of Young Scientists "Mechanics and Computer
Science", Chmielnicki, Ukraine, 2011(in print).
[2] Z. Rdzawski, W. Gáuchowski, J. Konieczny, Microstructure
and properties of CuTi4 alloy, Proceedings of the 13th
International Symposium IMSP’2010, Panukkale University,
Denizli, Turkey, 2010, 955-962.
[3] J. Konieczny, Z. Rdzawski, Misorientation in rolled CuTi4
alloy, Archives of Materials Science and Engineering 52/1
(2011) 5-12.
[4] Z. Rdzawski, J. Stobrawa, W. Gáuchowski, J. Konieczny,
Thermomechanical processing of CuTi4 alloy, Journal of
Achievements in Materials and Manufacturing Engineering
42 (2010) 9-25.
[5] W. Ozgowicz, E. Kalinowska-Ozgowicz, B. Grzegorczyk,
Thermomechanical treatment of low-alloy copper alloys of
the kind CuCo2Be and CuCo1NiBe, Journal of Achievements
in Materials and Manufacturing Engineering 46/2 (2011)
161-168.
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... Use of metals in medicine, food and water hygiene is dated back to antiquity [140][141][142] . Some metals such as copper (Cu) and silver (Ag) display potent biocidal activity against bacteria [143][144][145][146][147] , yeast, fungi 148 and viruses 143,149 . ...
Thesis
Full-text available
Access to safe drinking water is an essential human right and a crucial element to human survival. The quality of drinking water, has strong and direct impact on human health. Unless free of fecal contamination, water is unsafe to drink. Yet, to date, 2 billion people remain without access to safe drinking water. Consequently, the burden of waterborne disease remains a global threat to public health especially in developing countries. Fortunately, many interventions in the past decades aimed to provide safe drinking water in developing countries. Household water treatment (HHWT), provided individuals with a cheap and effective solution to treat water. Since its introduction, HHWT has dramatically improved the microbial quality of water, reduced the burden of waterborne diseases and its associated mortality. In particular, ceramic pot filters (CPFs) were described as one of the most sustainable, popular and effective HHWT systems in reducing waterborne diseases. In 2014, it was estimated that 4 million users rely on CPFs for water treatment. CPFs provide consumers with an adequate protection against bacteria and protozoa which accounts for its reported protection against waterborne diseases. However, CPFs are not highly protective against all waterborne pathogens since they fail to remove viruses. The exceptionally small size of viruses enables them to pass through the filter pores. Therefore, the objective of the thesis was to enhance virus removal in ceramic pot filters (CPFs). It was hypothesized that continued filtration of water through CPFs would lead to biofilm growth which might enhance virus removal. This hypothesis was examined using MS2 bacteriophage as ssRNA model virus. It was found that the growth of biofilm was dependent on the level of nutrients in raw water and as the subsequent virus (MS2) removal observed. The trade-off was the lower flow rates in high nutrient biofilms. Although high nutrient biofilms had better removal of virus (2.4 ± 0.5 logs), it reduced flow rates in the filters making them unusable. This limitation in virus removal and flow rate called for alternative solution. Therefore, the use of metals, namely silver (Ag) and copper (Cu), was examined as potential additives to CPFs to enhance virus removal. Ag is already being applied to CPFs in many factories but its contribution to virus removal has been controversial and only reported using model RNA virus (MS2). Cu is cheaper than Ag, hence it provided the possibility of an economical alternative or complementary addition. To that end, Cu and Ag were examined for their antiviral efficiency; separately and combined. MS2 (ssRNA) and PhiX 174 (ssDNA) bacteriophages were tested as conservative model viruses for RNA and DNA waterborne viruses. Ag (0.1 mg/L) exhibited antiviral efficiency against MS2 and PhiX 174 (≤ 2 log inactivation over 6 hours), which was reduced in the presence of 20 mg C/L of natural organic matter (NOM) in water. Overall, Cu (1 mg/L) was a more potent disinfectant than Ag (0.1 mg/L). For example, in water containing NOM (20 mg C/L), Cu inactivated ≥ 6 logs of MS2 over 3 hours, and to lesser extent PhiX 174 (≥ 1 log in 3 hours). Moreover, significant synergy of Cu and Ag in combination was observed for MS2 in the absence of NOM and to a lesser extend in presence of low NOM at pH ≥7. A synergistic effect of Cu and Ag together in disinfecting PhiX 174 was observed, but only in presence of NOM in water. Overall to achieve ≥ 3 logs of inactivation by Cu and/or Ag, hours of interaction between the metal(s) and the virus were needed. Because antiviral efficiency of Cu and Ag was observed, each was applied to ceramic filter discs (CFDs) according to the factory method (Filtron, Nicaragua) by painting metal ions solution using a hand brush. Virus removal by filtration through metal painted CFDs was examined. In addition, virus inactivation in the receptacles containing filtrate (in which there was leached Cu or Ag) was examined over 5.5 hours of storage. The contribution of Cu or Ag to enhancing virus removal by filtration was minor compared to the observed inactivation following hours of filtrate storage. This observation highlighted the value of utilizing virus inactivation as post treatment / post filtration option using Cu and/or Ag ions. Unfortunately, the rapid leaching of Cu from CFDs was an obstacle to testing Cu and Ag combination. It is therefore recommended to investigate alternative methods of Cu dosing other than painting. This thesis quantified the contribution of biofilm growth to improving virus removal in CPFs, although the effect varied. With the in-depth assessment of Cu and/ or Ag antiviral efficiency, examining the effect of water quality parameters on the achieved virus inactivation, the potential of Cu and Ag was assessed. Post treatment or safe water storage relying on Cu and Ag ions can be applied in principle to provide safe drinking water in compliance with the WHO requirements
... Copper has historically been known to have antimicrobial activity. Even in ancient Egypt, copper was used to preserve water and food, and also for medical purposes [30][31][32][33]. Today, copper is used in many medical approaches; in birth control, for example, as a copper IUD or copper chain [34]. ...
Article
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The COVID-19 Pandemic leads to an increased worldwide demand for personal protection equipment in the medical field, such as face masks. New approaches to satisfy this demand have been developed, and one example is the use of 3D printing face masks. The reusable 3D printed mask may also have a positive effect on the environment due to decreased littering. However, the microbial load on the 3D printed objects is often disregarded. Here we analyze the biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli on suspected antimicrobial Plactive™ PLA 3D printing filaments and non-antimicrobial Giantarm™ PLA. To characterize the biofilm-forming potential scanning electron microscopy (SEM), Confocal scanning electron microscopy (CLSM) and colony-forming unit assays (CFU) were performed. Attached cells could be observed on all tested 3D printing materials. Gram-negative strains P. aeruginosa and E. coli reveal a strong uniform growth independent of the tested 3D filament (for P. aeruginosa even with stressed induced growth reaction by Plactive™). Only Gram-positive S. aureus shows strong growth reduction on Plactive™. These results suggest that the postulated antimicrobial Plactive™ PLA does not affect Gram-negative bacteria species. These results indicate that reusable masks, while better for our environment, may pose another health risk.
... 2. Excess copper leads to damage to the microorganisms cell membrane, resulting in "leakage" of nutrients, which causes the cell to dry out and die [23]. ...
Article
Full-text available
Copper has long been known as a metal with outstanding antimicrobial properties. Although ancient healers were not familiar with the mechanisms of its influence on microorganisms, they had empirically established its effectiveness in sterilizing drinking water, disinfecting wounds, treating skin diseases, various infections and other maladies. Recently, there has been renewed interest in investigating copper and its alloys as possible materials that can limit the spread of bacteria and viruses, given that humanity is often facing various local epidemics, and rarely pandemics, as ongoing Corona virus, SARS CoV-2, first detected in March 2020. This paper reviews the recent literature in the research field of antimicrobial properties of metallic copper, its alloys and other copper - based materials, with the aim to promote their future implementation on contact surfaces, primarily in hospitals and institutions with a high frequency of people where the probability of spreading infection is increased.
... In addition, some metals have been used as antimicrobials, such as copper, which inhibits the growth of various bacteria such as methicillin-resistant S. aureus (MRSA), Clostridioides difficile, E. coli and Legionella pneumophila [18]. The antibiofilm effect of copper has been described in several bacteria, for example Salmonella Enteritidis and S. aureus [17,19]. ...
Article
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Biofilm formation in pathogenic bacteria is an important factor of resistance to antimicrobial treatments, allowing them to survive for a long time in their hosts. In the search for new antibiofilm agents, in this work we report the activity of a copper (I) complex, [Cu(NN1)2]ClO4, synthesized with Cu (I) and NN1, an imine ligand 6-((quinolin-2-ylmethylene)amino)-2H-chromen-2-one, a derivate of natural compound coumarin. The antibacterial and antibiofilm capacity was evaluated in Vibrio harveyi BB170 used as model bacteria. Antibacterial activity was measured in vitro by minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and half-maximal inhibitory concentration (IC50) determination. Antibiofilm capacity of copper (I) complex was analyzed by different concentrations of IC50 values. The results showed that the sub-IC50 concentration, 12.6 µg/mL of the copper (I) complex, was able to reduce biofilm formation by more than 75%, and bacterial viability was reduced by 50%. Inverted and confocal laser scanning microscopy showed that the [Cu(NN1)2]ClO4 complex affected the biofilm structure. Therefore, the copper (I) complex is effective as an antibiofilm compound in V. harveyi BB170.
... Dry powder of cupric oxide and copper sulphate was mixed and sprinkled on raw wounds to prevent infection. Wounds were treated with honey and red copper oxide mixture as an antiseptic (Konieczny and Rdzawski 2012). In India, the use of Tamra Patra (copper vessels) in numerous pharmacological treatments was recorded by Charaka in his work Charaka Samhita (Galib et al. 2011). ...
Article
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Copper (Cu) and its alloys are prospective materials in fighting covid-19 virus and several microbial pandemics, due to its excellent antiviral as well as antimicrobial properties. Even though many studies have proved that copper and its alloys exhibit antiviral properties, this research arena requires further research attention. Several studies conducted on copper and its alloys have proven that copper-based alloys possess excellent potential in controlling the spread of infectious diseases. Moreover, recent studies indicate that these alloys can effectively inactivate the covid-19 virus. In view of this, the present article reviews the importance of copper and its alloys in reducing the spread and infection of covid-19, which is a global pandemic. The electronic databases such as ScienceDirect, Web of Science and PubMed were searched for identifying relevant studies in the present review article. The review starts with a brief description on the history of copper usage in medicine followed by the effect of copper content in human body and antiviral mechanisms of copper against covid-19. The subsequent sections describe the distinctive copper based material systems such as alloys, nanomaterials and coating technologies in combating the spread of covid-19. Overall, copper based materials can be propitiously used as part of preventive and therapeutic strategies in the fight against covid-19 virus.
... Secondly, since copper is a known antimicrobial agent, we aimed to harness the known J o u r n a l P r e -p r o o f antimicrobial properties of copper [45][46][47][48][49], polydopamine based copper coatings (PDAM@Cu) were prepared via a simple dip coating method. It was hypothesised that an effective antibiofilm effect could be achieved via dual antimicrobial properties of copper present in the coating to reduce bacterial adhesion along with the dispersal action of endogenously generated NO catalysed by the copper. ...
Article
Introduction Peri-implantitis is a bacterially induced inflammatory disease which affects the hard and soft tissues around a dental implant. Microbial biofilm formation is an important causative factor in peri-implantitis. The aim of this study is to develop an effective multifunctional surface coating for antimicrobial property and to counteract oral biofilm-associated infections via a single polydopamine copper coating ([email protected]) on titanium implant surface to regulate endogenous nitric oxide (NO) generation. Methods [email protected] coatings were made with different concentrations of CuCl2 on titanium surfaces with a simple dip coating technique. Coatings were characterised to evaluate Cu concentrations as well as NO release rates from the coatings. Further, salivary biofilms were made on the coatings using Brain Heart Infusion (BHI) media in an anaerobic chamber. Biofilms were prepared with three different mixtures, one of which was saliva only, the second had an addition of sheep’s blood, and the third was prepared with NO donors S-nitrosoglutathione (GSNO) and L-glutathione (GSH) in the mixture of saliva and blood to evaluate the effects of endogenously produced NO on biofilms. The effectiveness of coated surfaces on biofilms were assessed using four different methods, namely, crystal violet assay, scanning electron microscopy imaging, 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) metabolic assay, and live/dead staining. Results NO release rates could be controlled with different Cu concentration in [email protected] coatings. NO generated from the [email protected] coatings effectively induced dispersal of biofilms shown by the reduction in biofilm biomass as well as reduced biofilm attachment in samples prepared with blood and NO donors. Cu ions released from the [email protected] coatings resulted in killing of the dispersed bacteria, which was evidenced by the live/dead cell staining and reduced metabolic activity noted from the XTT assay. In contrast, samples prepared with saliva showed no significant reduction in biofilms, indicating the important effect of endogenously generated NO on biofilm dispersal. Conclusion In conclusion, [email protected] coatings with NO generating surfaces have a dual anti-biofilm function, with a synergistic effect on biofilm dispersal from regulated NO generation and bactericidal effects from Cu ions from the coatings.
Article
The aim of researchers to create a matter that has a few preferences in diverse areas of pharmaceutical, agricultural, and natural remediation has fueled the creation and advancement of nanoscience and nanotechnology. Nanoparticles have been a primary focus of development in materials science throughout the last few decades. The study of copper nanoparticles (both in metallic copper and copper oxide) is economically attractive because copper is significantly more affordable than silver and gold. Moreover, the utilization of copper nanoparticles can substitute silver and gold nanoparticles in a few areas, specifically antimicrobial activity, antiviral activity, and others. Recently, copper nanoparticles research has been focused on the alternative fabrication process that concerns sustainability and environmentally friendly processes. Due to the several limitations of conventional methods, the novelty, and eco-friendly concern, studies have been shifted toward biological synthesis and its possibility to produce copper nanoparticles. This paper focuses on the alternative methods (biological synthesis) of copper nanoparticles, including the factors that affect the nanoparticles’ formation, such as temperature, precursor concentration, pH, reaction time, and the probable reduction mechanism. Also, as climate change triggers new infectious diseases caused by viruses and bacteria, this paper reviewed the copper nanoparticles’ ability as antimicrobial (antifungal and antibacterial) and antiviral agents. As precursors, the optimal temperatures are 80 °C (for CuSO4.5H2O and CuCl2.2H2O), 70 °C (for Cu(CH3COO)2.H2O), and 60 °C (for Cu(NO3)2.3H2O). The optimum precursor concentration is 2 mM for CuSO4.5H2O. The optimum pH ranges from 4 to 10. Each reductant and precursor has its own reaction time for forming copper nanoparticles, ranging from 1 to 120 minutes.
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SADRŽAJ – CONTENT Milica Preradović, Saša Papuga Third generation biofuels – cultivation methods and technologies for processing of microalgal biofuels ........................................................................ 249 Mihailo Mrdak, Časlav Lačnjevac, Marko Rakin, Đorđe Janaćković, Darko Veljić, Darko Bajić Characterisation of biocompatible layers of ZrO28%Y2O used in combination with other ceramics to modify the surface of implants ............. 262 Slobodan Cvetković, Mirjana Kijevčanin Balancing of energy flows in a life cycle of thermal energy production from biogas ................... 269 Josephath Jeyabal Maria Praveena, Jeyaraj Angelin Clara, Susai Santhammal Rajendran, Antony John Amalraj Inhibition of corrosion of mild steel in well water by an aqueous extract of soapnut (Sapindus Trifoliatus) ................................................................... 277 Slađana Tanasković, Mirjana Antonijević-Nikolić, Branka Dražić Thermal behavior and biological activity of [Co2(Cl)2 tpmc](BF4)2 complex ................................... 291 Aleksandra Mitovski, Vesna Grekulović, Nada Štrbac, Sanja Milutinović Jovanović, Kristina Božinović, Milica Zdravković Antimicrobial properties of copper and its alloys through the prism of the current SARS CoV-2 pandemic ..................................................................... 297 Victor David Arockiaraj Mallika Jeslina, Suyambulingam Jone Kirubavathy, Abdulhameed Al-Hashem, Susai Santhammal Rajendran RM Joany, Caslav Lacnjevac Inhibition of corrosion of mild steel by an alcoholic extract of a seaweed Sargassum muticum ....................................................................... 304 Abd El-Aziz S. Fouda, Safaa Eldin H. Etaiw, Essam El-Waseef Synthesis of two supramolecular coordination polymers and electrochemical evaluation of their corrosion inhibition performance on corrosion of Carbon Steel in Acidic medium ................................. 316 Imo Ejeagba Okorie, Nwokorie Romanus Chukwudi A review of fungal influenced corrosion of metals . 333 Leonid Dvorkin, Lyudmila Nihaeva Modified supersulfated cements ............................... 340 Manuscript preparation - Uputstvo za pripremu rada..... 349 Advertisements - Reklame ................................................ 353
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En el trabajo se aborda el uso de diferentes tipos de nanopartículas (NP’) con propiedades fotocatalíticas y antimicrobianas, con posible uso para mitigar la propagación del virus SARS-CoV-2 que provoca la enfermedad COVID-19. El trabajo está estructurado con énfasis en el mecanismo por el cual las NPs de Ag y Cu pueden eliminar virus y bacterias. Posteriormente, se aborda la preparación de materiales, como las zeolitas, que contienen impregnadas a las NPs de Ag y Cu. Otras de las NPs presentadas son las de ZnO y TiO2, las cuales también presentan altas eficiencias para eliminar microorganismos. Por último, se analizan algunos trabajos en donde las NPs, en suspensión o soportadas, se emplearon para preparar pinturas. Estas pinturas se evaluaron para degradar algunos contaminantes atmosféricos; no obstante, lo más interesante fue su uso como recubrimientos antibacterianos. Si bien, la mayoría de los trabajos se enfocaron en comprobar las propiedades antimicrobianas de las pinturas, su uso se puede extender hacia la inactivación de virus, como el SARS-CoV-2. Esto permitiría utilizar estos recubrimientos en zonas con alta frecuencia del virus, como es el caso de hospitales o áreas de alto contacto humano.
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Plasma Electrolytic Oxidation is gaining an increasing interest as surface modification technique for the fine tuning of both the chemical composition and the morphology of the surface of medical devices. Here, we propose a novel alkaline electrolyte, mainly composed of sodium tetraborate, to produce compact coatings with a high surface porosity and a Cu- and Zn-doped titania microstructure. A systematic exploration of the process parameters led to the identification of the optimal conditions to produce highly homogeneous coatings with micrometric pores and the doping of the outermost oxide layers. The obtained coatings show optimal chemical and topographical features for potential use for bone-contact applications.
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Purpose: The aim of the investigations is to test the influence of the complex thermomechanical treatment on the structure and mechanical properties of low-alloy copper alloys with cobalt, beryllium and nickel of the kind CuCo2Be (CB4) and CuCo1NiBe (CCNB).Design/methodology/approach: The range of investigations comprises an analysis of the complex technique of thermomechanical treatment of the investigated alloys and the conventional thermal treatment of these alloys, the analysis of their chemical composition, a static tensile test, measurement of their hardness, observations of their structure on a light microscope and a fractographic analysis on an electron scanning microscope.Findings: The analysis of the results of investigations concerning the mechanical effect properties permitted to determine the effect of the combined thermomechanical treatment and the comparatively performed precipitation hardening on the structure and mechanical properties of the investigated low-alloy kinds of copper. The character of cracking in the course of stretching were determined basing on fractographic tests.Practical implications: The investigated copper alloys subjected to a complex thermomechanical treatment display a higher strength and lower plastic properties in comparison with these properties achieved by means of the conventional heat treatment.Originality/value: Complex thermomechanical treatment ensures an optimal strength of the investigated alloys as well as satisfying plastic properties.
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Purpose: The properties and the microstructure of cold drown Cu-Nb composites have been investigated for their potential use as conductors in high field magnets. Nowadays, there is much activity in the development of such conductors all over the world. Design/methodology/approach: This study was aimed to investigate microstructure, mechanical and electrical properties of Cu-Nb15 wires. The investigated materials have been processed by vacuum furnace melting and casting, further hot forging and cold drawing. Alternatively material has been processed by one of the SPD (severe plastic deformation) method using oscillatory turning die pressing. Microstructure has been observed by optical and electron microscopy technics. Findings: The ultimate tensile strength versus cold deformation degree have been presented. These changes have been discussed in relation to the microstructure evolution. Practical implications: The obtained mechanical and electrical properties (UTS over 900 MPa and electrical conductivity over 40 MS/m) correspond to requirements for production of long pulsed 60T magnets. Originality/value: Original SPD technic applied for Cu-Nb microcomposite deformation cause initial microstructure refinement and improves effectiveness of wire production process.
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Purpose: One of the reasons behind the interest in copper titanium alloys was development of new materials to substitute copper beryllium alloys. The reason for selecting that material for studies was that in the early stages of decomposition of CuTi4 alloy a spinodal transformation takes place and ordering processes begin. Proper selection of heat treatment and plastic working conditions provides possibilities to produce very wide range of sets of properties by formation of the required alloy microstructure. Therefore the main objective of the study was to capture the changes in precipitation kinetics, especially in the relations between supersaturation and ageing or between supersaturaion, cold deformation and ageing in connection to the changes in microstructure and functional properties (mainly changes in hardness and electrical conductivity). Design/methodology/approach: Melting of the charge material was conducted in medium-frequency induction furnace, in a graphite crucible. The melted material after bath preparation was poured into a cast iron ingot mould (with graphite grease applied on the inside) of dimensions 35 x 120 x 250 mm. The ingots after casting were peeled. The treated ingots were heated in resistance furnace at 900ºC for 1.5 hour and rolled down on a reversible two-high mill. Findings: Decomposition of supersaturated solid solution in that alloy is similar to the alloys produced in laboratory scale. The observed differences in microstructure after supersaturation were related to the presence of undissolved Ti particles and increased segregation of titanium distribution in copper matrix including microareas of individual grains. The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the alloy. Research limitations/implications: Cold deformation (50% reduction) of the alloy after supersaturation changes the mechanism and kinetics of precipitation and provides possibilities for production of broader sets of functional properties. It is expected that widening of the cold deformation range should result in more complete characteristics of material properties, suitable for the foreseen applications. Similar effects can be expected after application of cold deformation after ageing. Practical implications: The elaborated research results present some utilitarian qualities since they can be used in development of process conditions for industrial scale production of strips from CuTi4 alloy of defined properties and operating qualities. Originality/value: The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the Cu-Ti alloys.
Conference Paper
Full-text available
One of the reasons behind the interest in copper titanium alloys was development of new materials to substitute beryllium copper. The reason for selecting that material for studies was that in the early stages of decomposition of CuTi4 alloy a spinodal transformation takes place and ordering processes begin. Proper selection of heat treatment and plastic working conditions provides possibilities to produce very wide ranges of sets of properties by formation of the required alloy microstructure. Therefore the main objective of the study was to capture the changes in precipitation kinetics, especially in the relations between supersaturation and ageing and between supersaturaion, cold deformation and ageing in connection to the changes in microstructure and functional properties (mainly changes in hardness and electrical conductivity).
Article
Full-text available
Purpose: The aim of the work is to investigate the microstructure heat treated and cold rolled commercial copper alloy CuTi4. Design/methodology/approach: The Investigations of the structure were made on ZEISS SUPRA 25 with EBSD method. Observations of the structure on thin foils were made on the JOEL 3010 transmission electron microscope (TEM). Findings: Decomposition of supersaturated solid solution in that alloy is similar to the alloys produced in laboratory scale. The observed differences in microstructure after supersaturation were related to the presence of undissolved Ti particles and increased segregation of titanium distribution in copper matrix including microareas of individual grains. The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the alloy. Research limitations/implications: Cold deformation (50% reduction) of the alloy after supersaturation changes the mechanism and kinetics of precipitation and provides possibilities for production of broader sets of functional properties. It is expected that widening of the cold deformation range should result in more complete characteristics of material properties, suitable for the foreseen applications. Similar effects can be expected after application of cold deformation after ageing. Practical implications: The elaborated research results present some utilitarian qualities since they can be used in development of process conditions for industrial scale production of strips from CuTi4 alloy of defined properties and operating qualities. Originality/value: The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the Cu-Ti alloys
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The as-cast microstructure and properties of K465 nickel-base cast superalloy are investigated, as well as they are during heat-treatment. The results showed that the alloy as-cast is composed of γ phase, γ′ phase, (γ+γ′) eutectic and MC carbide, and its average tensile strength and percentage elongation at ambient temperature are 960 MPa and 6.0%, respectively. The creep rupture life under the condition of 975°C/230 MPa is 28.1 h. After the 1210°C/4 h solution treatment followed by air-cooling, the crystal boundary MC carbide partly becomes M6C one with γ′ phase particle size reduced to 0.1-0.2 μm and the tensile strength and elongation at ambient temperature up to 1055 MPa and 4.0%, respectively. The creep rupture life is 50.3 h under the same condition. With 0.02 wt% Mg added in, the grains of MC carbide in the alloy is spheroidized, and the average tensile strength and elongation of the alloy at ambient temperature are 990?MPa and 5.0%, respectively, with a creep rupture life up to 56.3 h under the same conditon.
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This treatise reviews medical uses of various forms of copper recorded throughout the history of mankind. Ancient Egyptian papyri, Greek, Roman, Aztec, Hindu, and Persian writings as well as medieval and subsequent European medical literature record various consistent medical uses of copper. There are many reported uses of copper and its compounds as antibacterial, antiinflammatory, antiarrhythmic, antitumor, and antiepileptic agents. Copper was also recommended to promote wound healing and heal broken bones. Tracing the development of folk medicine and the many rediscoveries of the beneficial effects of copper compounds leads to the suggestion that serious consideration should be given to modern-day medical uses of complexes of this essential metalloelement.
Book
Hafiz, S., Kinghorn, GR, and McEntegart, MG (1981). Br. J. Vener. Dis. 57, 382- 386. Hafiz, S., Kinghorn, GR, and McEntegart, MG (1982). Lancet 2, 872. Hammond, GW, Lian, CJ, Wilt, J. C, and Ronald, AR (1978a). J. Clin. Microbiol.