ANALYSIS OF STUDIES ON THE ANTIBACTERIAL PROPERTIES OF COPPER SURFACES

ANALYSIS OF STUDIES ON THE ANTIBACTERIAL PROPERTIES OF COPPER SURFACES

Mukhtar Balaubaev

Master's student, D.Serikbayev East Kazakhstan Technical University,

Kazakhstan, Ust-Kamenogorsk

Sergey Plotnikov

PhD Doctor, Professor, D.Serikbayev East Kazakhstan Technical University,

Kazakhstan, Ust-Kamenogorsk

ABSTRACT

Contamination of the surface by microbes leads to a number of harmful consequences, such as infections. One of the measures to prevent surface contamination is to impart antimicrobial properties to surfaces. The antimicrobial properties of copper have been known since ancient times, and the recent resurgence in the use of copper for use as antimicrobial materials or coatings is due to growing concerns about antibiotic resistance and the need to reduce the use of antibiotics. Copper, unlike silver, demonstrates rapid and high bactericidal efficacy against pathogens in close contact in indoor environmental conditions, which expands the scope of its application. This review highlights the mechanisms underlying the powerful antimicrobial properties of copper, the development and manufacture of copper-based coatings, as well as their potential for practical application.

Keywords: antimicrobial coatings, copper, antimicrobial mechanisms, contact destruction.

Introduction

Copper (Cu) is the 26th element in the earth's crust and the oldest metal [1] known to man, who used it since 9000 BC. [2] The potential of copper in antiseptic and health-improving action was recognized by key civilizations as early as 3000 BC and mentioned in the original books of Hippocrates [3] and ancient texts of Ayurveda. [4,5] The first article on Cu as an antimicrobial coating in the Scopus database was published in 1962, which is more than 30 years earlier than the publication of Ag (Fig. 1a) [6], and over the past years the number of studies of two varieties of antimicrobial coatings is constantly growing. The number of patents issued for antimicrobial copper coatings has also been growing steadily over the past 20 years (Fig. 1b), which focuses on the commercial significance of these coatings. Cu and either its compounds have been studied for use against marine biofouling [7,8], as well as for their efficacy against a number of pathogenic microorganisms, such as gram-positive LHC

Figure 1. (a) Graph of the number of articles published in Scopus (as of July 21, 2018) on various types of antimicrobial surface coatings (in relation to their main active ingredient) [6]. (b) A graph of patents granted between 2000 and 2019, obtained from the PatSnap database using the search query "antimicrobial copper coating"

Antimicrobial activity of copper.

To use the antimicrobial properties of copper, the surfaces that touch the skin and food must be made of copper or a copper alloy. This can be achieved by using solid copper equipment or by using copper surface spraying. The plasma sputtering process uses a DC electric arc to produce a stream of high-temperature ionized plasma gas, which acts as a sputtering heat source. The coating material, in the form of a powder, is transferred by an inert gas and injected into a plasma jet, where the powder melts and is ejected to the surface intended for spraying.

Studies have shown that large amounts of copper ions were absorbed by E. coli in 90 minutes when the cells were applied to copper samples by means of an aqueous suspension (standing drop). When the cells were applied to copper using a minimum amount of liquid and with a drying time of 5 seconds, the accumulation of copper ions by the cells was even more pronounced, reaching a concentration in a fraction of a second.

The level of copper ions in the cells remained high during the destruction phase, which suggests that the cells are suppressed by their intracellular copper [5]. The granular structure of copper matter affects the diffusion of ions and thus contributes to the destruction of bacteria by copper ions.

Galvanic method of copper plating of the surface

To use the antimicrobial properties of copper, the surfaces touching the skin and food must consist of copper or a copper alloy.

This can be achieved by using solid copper equipment or by means of a copper surface coating. In general, for price reasons, copper coatings are preferable to a solid copper structure. There are various methods of spraying metal for applying a copper coating on devices that can transmit microorganisms, therefore it is desirable to establish the optimal method of spraying. Accordingly, three metal spraying techniques are evaluated in terms of the antimicrobial effect of the copper surface obtained through each of these techniques.

Copper plating is the process of applying a thin layer of copper to the surface of an object. It is performed by the galvanic method, i.e. by transferring copper ions from a positively charged source to a negatively charged surface to be treated. Most often, the process of electroplating copper is a preparatory stage before coating with nickel and chromium, but often copper plating of metal becomes an independent type of finishing. Electroplating is widely used, for which it is required to create a coating of copper. There are two options for copper plating at home: With immersion of the workpiece in the electrolyte and without immersion.

With immersion of the workpiece in the electrolyte. To perform the procedure, it is necessary to have a container with an electrolyte that has a sufficient volume. After preliminary preparation, consisting in cleaning the surface with sandpaper and washing in a hot soda solution, the object is connected to the negative electrode and immersed in the electrolyte for a certain time.

Conclusion

The results of the studies demonstrate the effectiveness of the destruction of bacteria when using plasma spraying of copper. The plasma sputtering method precipitates molten particles at a relatively low speed (600 m / s). Thus, the Vickers hardness values for the copper coating obtained by plasma deposition were 94. Ionic diffusion in metals is enhanced by the presence of dislocations of particles, known as" diffusion along dislocation lines", and ionic diffusion occurs mainly due to these dislocations.

References:

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