Antimicrobial Properties Of Copper Research Articles

Hydroxyl Radical Generating Monovalent Copper Particles for Antimicrobial Application

The antimicrobial properties of copper are well-known but maintaining a low oxidation state of Cu in particles is difficult. Herein, antimicrobial CuxP particles were synthesized through phosphorization of Cu(OH)2, to lock copper in its monovalent state (as Cu3P). We found that the phosphorization could be achieved at temperatures as low as 200°C, with stable surface presence of Cu(I) on the resulting CuxP particles. Cu(I) can act as a one-electron reducing agent for molecular oxygen, to generate the highly reactive hydroxyl radical. In this study, CuxP displayed antibacterial activities on the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with minimum inhibitory concentrations of 32 mg/L for the highest temperature particles (350°C) on both model bacteria. The evident membrane damage is consistent with the intended hydroxyl radical bacterial targeting mechanism. Low-temperature CuxP, although exhibiting lower antibacterial efficacies than those of the higher temperature variant, still showed competitive growth inhibiting activities when compared to other reported antimicrobial copper-based particles. The present work showcases advancements in particle technology that can lead to the development of a more robust antimicrobial agent, presenting a potent additive for self-disinfection applications.

Copper-coated hospital surfaces: reduction of total bacterial loads and resistant Acinetobacter spp.

Healthcare-associated infections (HAIs) represent a global challenge and an even more staggering concern when related to microorganisms capable of resisting and surviving for long periods in the environment, such as Acinetobacter spp. Strategies that allow a reduction of pathogens from hospital environments represent an additional barrier in infection control protocols, minimizing transmission to hospitalized patients. Considering the antimicrobial properties of copper, here, the bacterial load and the presence of Acinetobacter spp. were monitored on high handling surfaces covered by 99.9% copper films on intensive and non-intensive care unit bedrooms in a tertiary care hospital. Firstly, copper-coated films were able to inhibit the adhesion and biofilm formation of A. baumannii strains in in vitro assays. On the other hand, Acinetobacter spp. were isolated from both copper-coated and uncoated surfaces in the hospital, although the majority was detected on surfaces without copper. All carbapenem-resistant A. baumannii isolates identified harbored the blaoxa-23 gene, while the A. nosocomialis isolates were susceptible to most antimicrobials tested. All isolates were susceptible to polymyxin B. Regarding the total aerobic bacteria, surfaces with copper-coated films presented lower total loads than those detected for controls. Copper coating films may be a workable strategy to mitigate HAIs, given their potential in reducing bacterial loads in nosocomial environments, including threatening pathogens like A. baumannii.

Significance of additive manufacturing amidst the pandemic

In the light of COVID-19 pandemic, a global shortage for Personnel Protective Equipment (PPE) led to the search for an alternative to fill the gap where additive manufacturing made necessary development of rapid design and adaptive filtering masks for local manufacturing using 3D printing to help the frontline workers. The review focuses on the utilization of antimicrobial materials in additive manufacturing with the use of bespoke design to facilitate and respond to the disruptions in the medical supply chain. Previous studies confirmed the age-old theory of copper as an antimicrobial material with contact killing properties. The antimicrobial properties of copper have been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. Combining the properties of copper in a PLA (Polylactic Acid) filament as a nano composite, Copper-3D facilitates the antimicrobial properties to any 3D printed object. Provided this flexibility of 3D printing, the use of masks designed distinctively based on the 3D scan of an individual’s facial structures as an efficient Personnel Protective Equipment is also addressed. Additive manufacturing as a support to the shortage of medical devices and a responsive method to the disruption in the supply chain is discussed.

Antibacterial property, corrosion and discoloration resistance of pure copper containing Zn or Ni.

This study focused on the effects of Zn and Ni addition on the antibacterial properties and corrosion resistance of copper alloys. The antimicrobial properties of copper and copper alloys were evaluated using Escherichia coli ATCC 8739 bacterial strain by employing the overlay and plate counting methods. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface composition of the alloy after contact with bacteria. A salt spray method was used to simulate an artificial sweat contact environment to test the discoloration and corrosion resistance of the alloy, and scanning electron microscopy (SEM) was used to analyze the film layer and surface material composition of the corroded samples. The addition of Ni reduced the antibacterial performance of pure copper; however, the antibacterial performance of the alloy remained fast and efficient after the addition of Zn. Moreover, the addition of Zn and Ni significantly improved the corrosion resistance and surface discoloration of copper alloys in artificial sweat environments. This study provided support for the future application of copper alloys as antimicrobial surface-contact materials with safer public and medical environments in the face of diseases spread by large populations.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s12598-022-02098-8.

Antimicrobial Properties of Copper and d-Orbital Capture

The purpose of this note is to stimulate interest in measuring and characterizing the emitted ultraviolet frequencies in antimicrobial copper materials. Antimicrobial sanitizing materials are urgently needed to limit the spread of COVID-19 virus. In the current pandemic, ultraviolet radiation is often used for sterilization. It is shown that 3 d-orbital capture in copper can result in radiation generated by copper materials. Since ultraviolet radiation is known to be effective in antimicrobial sterilization, it is logical to assume that the radiation formed by copper occurs in the ultraviolet region. Electron transitions in 3 d-orbital capture are expected to occur in this region. A description of the 3 d-orbital capture process, and the origin of the associated frequency, is given. It is shown that for Group 1B elements the strength of electron affinity in the d-orbital capture process increases with increasing Periodic Table period number, n. This is the opposite of other electron affinity properties for atoms that decrease wth an increase in n. A brief discussion of the relationship of d-orbital capture to the chemical inertness of gold is given. The same type of d-orbital capture process that occurs in antimicrobial copper occurs in high temperature superconducting cuprates.

Copper Surfaces in Biofilm Control.

Biofilms are structures comprising microorganisms associated to surfaces and enclosed by an extracellular polymeric matrix produced by the colonizer cells. These structures protect microorganisms from adverse environmental conditions. Biofilms are typically associated with several negative impacts for health and industries and no effective strategy for their complete control/eradication has been identified so far. The antimicrobial properties of copper are well recognized among the scientific community, which increased their interest for the use of these materials in different applications. In this review the use of different copper materials (copper, copper alloys, nanoparticles and copper-based coatings) in medical settings, industrial equipment and plumbing systems will be discussed considering their potential to prevent and control biofilm formation. Particular attention is given to the mode of action of copper materials. The putative impact of copper materials in the health and/or products quality is reviewed taking into account their main use and the possible effects on the spread of antimicrobial resistance.

In vitro inactivation of Mycobacterium avium subsp. paratuberculosis (MAP) by use of copper ions

BackgroundMycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis, a contagious infectious disease that affects domestic and wild ruminants causing chronic inflammation of the intestine. MAP has proven to be very resistant to both physical and chemical processes, making it difficult to control this pathogen. Based on the recognized antimicrobial properties of copper, the objective of this study was to evaluate the effectiveness of copper ions to reduce MAP numbers and/or MAP viability in a fluid matrix. Besides, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli were used as controls of the effectiveness of copper ions. MAP-spiked PBS was subjected to copper ions treatment at 24 V for 5 min and the PBS suspensions were sampled before and after treatment. MAP viability and quantification were determined using three complementary techniques: a phage amplification assay, MGIT culture and qPCR.ResultsModerate numbers (103 CFU ml−1) of the two control bacteria were completely eliminated by treatment with copper ions. For MAP, copper ions treatment reduced both the viability and numbers of this pathogen. Phage assay information quickly showed that copper ions (24 V for 5 min) resulted in a significant reduction in viable MAP. MGIT culture results over time showed statistically significant differences in time-to-detection (TTD) values between PRE and POST treatment. MAP genome equivalent estimates for PBS suspensions indicated that MAP numbers were lower in samples POST-treatment with copper ions than PRE-treatment.ConclusionsThe use of copper ions resulted in a significant reduction of MAP in a liquid matrix, although some MAP survival on some occasions was observed.

Structural, Antimicrobial and Electrochemical Properties of Cu/TiO2 Nanocomposites

The antimicrobial properties of copper (Cu) based titanium dioxide (TiO 2 ) nanocomposites have been actively investigated in the present study. Sonochemical method was employed for the synthesis of nanocomposites having different wt.% ratios of Cu, TiO 2 nanomaterials. In Cu-based TiO 2 nanocomposites, the size of Cu nanoparticle plays a crucial role in deciding the bactericidal performance activity. The XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (Scanning electron microscope), HR-TEM (High-resolution transmission electron microscope) and cyclic voltammeter used to analyze crystallite size, functional groups, morphology, particle size and electrochemical activity respectively of well-formed nanocomposites. Detailed studies on antimicrobial activity of prepared nanomaterials are carried out on Gram positive, Gram negative and Yeast i.e., Staphylococcus aureus (ATCC 25923); Bacillus subtilis (ATCC 6633); Escherichia coli (ATCC 25922) and Candida ablicans (ATCC 10231) by disc diffusion method. The obtained antibacterial activity was correlated with electrochemical studies, originate to be best suitable for the present application. The crystallite size was calculated from XRD and is found to be 16.6 – 22.7 nm and 42.2 – 56 nm for Cu/TiO 2 at different wt.% ratio respectively. Zone of inhibition is increasing as the concentration of Cu based TiO 2 nanocomposites are increasing. The result showed that Cu based nanocomposites has a very promising property as an antimicrobial material and can be utilized in wide range of biomedical applications.

Contact killing and antimicrobial properties of copper.

With the emergence of antibiotic resistance, the interest for antimicrobial agents has recently increased again in public health. Copper was recognized in 2008 by the United States Environmental Protection Agency (EPA) as the first metallic antimicrobial agent. This led to many investigations of the various properties of copper as an antibacterial, antifungal and antiviral agent. This review summarizes the latest findings about 'contact killing', the mechanism of action of copper nanoparticles and the different ways micro-organisms develop resistance to copper.

Cytotoxic and Antimicrobial Properties of Copper(II) Complexes of Pyridine and Benzimidazole Derivatives

The cytotoxic and antimicrobial activity of a series of six copper(II) complexes with phosphate and hydroxymethyl derivatives of pyridine and benzimidazole were investigated. The complexes and the corresponding free ligands were tested against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 25922, Proteus hauseri ATCC 13315, and Candida albicans ATCC 10231. Among the tested copper(II) complexes, compounds 2 and 5 containing 1H‐benzimidazol‐2‐ylmethyl diethyl phosphate and 2‐(hydroxymethyl)benzimidazole as ligands, respectively, were most active and limited the growth of S. aureus, E. coli, and C. albicans by 30–60 % according to concentration and microorganism. The in vitro cytotoxic activity of the CuII complexes and free ligands towards cancerous B16 (murine melanoma) and non‐cancerous 10T1/2 (murine fibroblasts) cell lines was determined. The 10T1/2 cells were treated with the compounds at concentrations equal to IC50 values for B16 cells. In spite of the use of relatively high concentrations of the complexes, the viability of 10T1/2 cells was very high, ca. 80 % in some cases. Stability of the CuII complexes was evaluated in water solutions by UV/Vis spectroscopy. The copper(II) complex of 4‐(hydroxymethyl)pyridine was synthesized and identified.

Preparation of photochemical coatings of metal films (copper, silver and gold) on dielectric surfaces and studying their antimicrobial properties

The metals of the copper subgroup (copper, silver, gold) are known for its antibacterial properties for a long time. For example, among the antimicrobial properties of copper, it should be noted its ability effectively inactivate MRSA and influenza a virus including subtype H1N1, called “swine flu”. In this study we developed a number of methods of gold, copper and silver and its mixture coatings of dielectric materials and applied these coatings on textile fabrics. Subsequent antimicrobial testing of coated fabrics were conducted using two bacteria E. coli and S. aureus.Obtained coatings were subjected to numerous washing and creasing to prove its resistance.

Green synthesis of rifampicin-loaded copper nanoparticles with enhanced antimicrobial activity.

The antimicrobial properties of copper and rifampicin-loaded copper nanoparticles were investigated using four strains: Staphylococcus aureus, Escherichia coli, Bacillus pumilis and Pseudomonas fluorescens. Spherical-shaped copper nanoparticles were synthesized via green reduction method from the peppermint extract. It was found that adsorption of rifampicin on the copper nanosurface enhances its biological activity and prevents the development of resistance. The interactions between rifampicin-copper nanoparticles and bacteria cells were monitored using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). It was proven that loaded with rifampicin copper nanoparticles were able to damage the S. aureus cell membrane and facilitate the bacteria biofilm matrix disintegration. Moreover, the DNA decomposition of S. aureus treated with copper and rifampicin-copper nanoparticles was confirmed by agarose gel electrophoresis. The results obtained indicate that adsorption of rifampicin on the copper nanoparticles surface might provide the reduction of antibiotic dosage and prevent its adverse side effects.

Antibacterial Effect of Copper on Microorganisms Isolated from Bovine Mastitis.

The antimicrobial properties of copper have been recognized for several years; applying these properties to the prevention of diseases such as bovine mastitis is a new area of research. The aim of the present study was to evaluate in vitro the antimicrobial activity of copper on bacteria isolated from subclinical and clinical mastitis milk samples from two regions in Chile. A total of 327 microorganisms were recovered between March and September 2013, with different prevalence by sample origin (25 and 75% from the central and southern regions of Chile, respectively). In the central region, Escherichia coli and coagulase negative Staphylococci (CNS) were the most frequently detected in clinical mastitis cases (33%), while in the southern region S. uberis, S. aureus, and CNS were detected with frequencies of 22, 21, and 18%, respectively. Antibiotic susceptibility studies revealed that 34% of isolates were resistant to one or more antibiotics and the resistance profile was different between bacterial species and origins of isolation of the bacteria. The minimum inhibitory concentration of copper (MIC-Cu) was evaluated in all the isolates; results revealed that a concentration as low as 250 ppm copper was able to inhibit the great majority of microorganisms analyzed (65% of isolates). The remaining isolates showed a MIC-Cu between 375 and 700 ppm copper, and no growth was observed at 1000 ppm. A linear relationship was found between the logarithm of viable bacteria number and time of contact with copper. With the application of the same concentration of copper (250 ppm), CNS showed the highest tolerance to copper, followed by S. uberis and S. aureus; the least resistant was E. coli. Based on these in vitro results, copper preparations could represent a good alternative to dipping solutions, aimed at preventing the presence and multiplication of potentially pathogenic microorganisms involved in bovine mastitis disease.

Synthesis, characterization, and evaluation of the antimicrobial potential of copper(II) coordination complexes with quinolone and p-xylenyl-linked quinolone ligands

The antimicrobial properties of copper have been known to mankind since the ancient times. In a coordination chemistry approach to develop novel antimicrobial agents, the quinolone antimicrobial agents ciprofloxacin (Hcipro) and pipemidic acid (Hpia), as well as dimers thereof (piperazinyl-linked with a p-xylenyl moiety) were complexed with copper(II). The synthesis and antimicrobial evaluation of bis(ciprofloxacino)copper(II) [Cu(cipro)2], bis(pipemido)copper(II) [Cu(pia)2], and the corresponding dimer complexes, [Cu2(ciproXcipro)2] and [Cu2(piaXpia)2], are reported. No combinational or synergistic effect between copper(II) and the respective quinolone ligands was observed in vitro.

A demonstration of the antimicrobial effectiveness of various copper surfaces

BackgroundBacterial contamination on touch surfaces results in increased risk of infection. In the last few decades, work has been done on the antimicrobial properties of copper and its alloys against a range of micro-organisms threatening public health in food processing, healthcare and air conditioning applications; however, an optimum copper method of surface deposition and mass structure has not been identified.ResultsA proof-of-concept study of the disinfection effectiveness of three copper surfaces was performed. The surfaces were produced by the deposition of copper using three methods of thermal spray, namely, plasma spray, wire arc spray and cold spray The surfaces were then inoculated with meticillin-resistant Staphylococcus aureus (MRSA). After a two hour exposure to the surfaces, the surviving MRSA were assayed and the results compared.The differences in the copper depositions produced by the three thermal spray methods were examined in order to explain the mechanism that causes the observed differences in MRSA killing efficiencies. The cold spray deposition method was significantly more effective than the other methods. It was determined that work hardening caused by the high velocity particle impacts created by the cold spray technique results in a copper microstructure that enhances ionic diffusion, and copper ions are principally responsible for antimicrobial activity.ConclusionsThis test showed significant microbiologic differences between coatings produced by different spray techniques and demonstrates the importance of the copper application technique. The cold spray technique shows superior anti-microbial effectiveness caused by the high impact velocity imparted to the sprayed particles which results in high dislocation density and high ionic diffusivity.

Synthesis, crystal structures and antimicrobial properties of copper(II)-thiophene-2,5-dicarboxylate complexes with N-donor ligands

Eight new copper(II)-thiophene-2,5-dicarboxylate (tdc) complexes with N-methylethylenediamine (nmen), [Cu(H2O)2(nmen)2](tdc) (1), N,N-dimethylethylenediamine (nnen), [Cu(tdc)(nnen)2]·H2O (2), N,N′-dimethylethylenediamine (dmen), [Cu(μ-tdc)(H2O)(dmen)]n (3), N,N,N′,N′-tetramethylethylenediamine (tmen), {[Cu(μ-tdc)(tmen)2]·H2O}n (4), N-ethylethylenediamine (neten), trans-[Cu(H2O)2(neten)2](tdc)·2H2O (5), N,N′-diethylethylenediamine (deten), trans-[Cu(H2O)2(deten)2](tdc) (6), N,N-diethylethylenediamine (eten), [Cu(μ-tdc)(eten)]n (7), and N-methyl-1,3-propanediamine (nmpen), [Cu(tdc)(nmpen)2] (8), have been synthesized and characterized by elemental analyses, magnetic moments, thermal analyses (TG, DTG and DTA), UV–Vis and IR spectra. The crystal structures of 2, 3, 5 and 7 were determined by single crystal X-ray diffraction studies. In 1, 5 and 6, the Cu(II) ions are coordinated by two aqua ligands and four nitrogen atoms of nmen, neten and deten, respectively and thiophene-2,5-dicarboxylate (tdc) acts as a counterion. In 2, 4 and 8, tdc coordinates to the Cu(II) ions through the oxygen atom of the carboxylate group as a monodentate ligand, and the distorted square pyramidal geometries of the Cu(II) ions of 2, 4 and 8 are completed by the nnen, tmen and nmpen ligands, respectively, which act as bidentate ligands. In 3 and 7, the tdc ligand exhibits tridentate-μ2 and tetradentate-μ2 bridging modes, being coordinated through three and four carboxylate oxygens atoms, respectively. The crystal packing of the complexes is a composite of intermolecular hydrogen bonding interactions. Furthermore, in vitro antimicrobial activities of these complexes were tested against selected wild type microorganisms using MIC methods.

Copper(II) complexes as superoxide dismutase mimics: Synthesis, characterization, crystal structure and bioactivity of copper(II) complexes

Two new copper(II) complexes of the type [Cu(L)X 2), where L = (E)-N-phenyl-2-[phenyl (pyridine-2-yl)methylene]hydrazinecarboxamide X = Cl/Br have been synthesized and characterized by elemental analyses, FAB (fast atomic bombardment) magnetic measurements, electronic absorption, conductivity measurements cyclic voltammetry (CV) and Electron paramagnetic resonance (epr) spectroscopy. The structures of these complexes determined by single crystal X-ray crystallography show a distorted square based pyramidal (DSBP) geometry around copper(II) metal center. The distorted CuN 2OX (X = Cl/Br) basal plane in them is comprised of two nitrogen and one oxygen atoms of the meridionally coordinated ligand and a chloride or bromide ion and axial position is occupied by other halide ion. The epr spectra of these complexes in frozen solutions of DMSO showed a signal at g ca. 2. The trend in g-value ( g || > g ⊥ > 2.00) suggest that the unpaired electron on copper(II) has d x 2 - y 2 character. Biological activities in terms of superoxide dismutase (SOD) and antimicrobial properties of copper(II) complexes have also been measured. The superoxide dismutase activity reveals that these two complexes catalyze the fast disproportionation of superoxide in DMSO solution.