Microparticle antibacterial hybrid system

Abstract

The present invention relates to a hybrid material, particularly as an additive for materials, substances, and / or coating materials for producing antibacterial, antiviral, and / or fungicidal effects, comprising particles each comprising at least one support material at least partially coated with at least two different metals, where at least one first metal and one second metal are in conductive contact with each other at least via their respective surfaces. According to the present invention, the first metal comprises at least one semiconductor compound of at least one transition metal element exhibiting multiple oxidation states and allowing a change of oxidation state via catalytically active centers, and the second metal comprises at least one conductive silver semiconductor. Both metals establish a half-cell that is short-circuited in the presence of water and oxygen, thus developing the antibacterial, antiviral, and / or fungicidal effect, and the support material comprises at least one material compatible with the substance and / or coating material and their use. The hybrid material according to the present invention can be advantageously used as an antibacterial additive for various materials, substances, and / or coating materials, preferably lacquers, paints, plasters, polymers, and / or cellulose.

Description

[Technical Field]

[0001] The present invention relates in particular to a hybrid material, which is provided as an additive for materials, substances and / or coating materials for producing an antibacterial, antiviral and / or fungicidal effect, and which comprises particles each comprising at least one carrier material at least partially coated with at least two different metals, wherein at least one first metal and one second metal are in conductive contact with each other at least by their respective surfaces. The present invention further relates to a method for producing a particulate hybrid material having antibacterial activity, and to uses of such a particulate hybrid material.

[0002] In principle, additives must possess many properties that are often not achievable with the base material alone. The desired property profile can be tailored by surface technology. Often, properties are required that cannot be achieved with a single material alone, but only with several surface materials consisting of different components. Such multi-component systems are also called hybrid material systems.

[0003] Antibacterial devices and products have been used for some time in sensitive fields such as medical and sanitation technology and food processing. The current SARS-CoV-2 pandemic, as well as many previous epidemics, have deeply ingrained the topic of hygiene and protection against pathogenic microorganisms in the public consciousness, extending the need for antibacterial protection to all areas of life. Due to its significant negative impact on the global economy, the current situation highlights the importance of antibacterial protection and significantly increases the need for highly effective antibacterial protective materials. Particularly for items that are frequently touched or serve as antibacterial protection, such as mouth masks, there is an increasing need for stronger and more durable antibacterial systems that can be well processed and integrated into products. [Background technology]

[0004] Previous solutions in the field of antimicrobial additives have been limited to the use of conventional biocidal substances released by leaching. Oligoactive metals such as silver, copper, or zinc, their chemical modifications, organic substances such as triclosan and isothiazolinones, and organometallic substances such as zinc pyrithione are used. These substances are stored in a depot within a carrier matrix. Once the depot is depleted, the antimicrobial effect of the carrier material no longer exists. New developments in the field of antimicrobial additives are primarily related to the production of particles for powder coating, improved dispersion of biocides in polymeric carrier matrices, prevention of discoloration of the carrier matrix by added biocides, and controlled release of biocidal active ingredients through encapsulation. However, promising antimicrobial systems are expected to exert sufficient spontaneous action to prevent microbial growth while simultaneously remaining antimicrobially effective for long periods by slowly releasing toxicologically and ecotoxicologically acceptable amounts of active substances.

[0005] WO 2008 / 046513 discloses a bioactive metal coating containing silver, ruthenium, and a vitamin, which is used for sterilization, disinfection, and decontamination of water or aqueous solutions. The combination of silver with ruthenium and a vitamin, such as ascorbic acid, results in faster and more efficient killing of microorganisms. At the same time, these bioactive metal surfaces prevent microbial colonization and the attachment or stable deposition of problematic biomolecules, such as DNA, RNA, or proteins. Upon contact with water or aqueous solutions, the coating produces a self-cleaning surface that establishes and maintains its sterility very quickly and efficiently over time.

[0006] European Patent No. 0677989 discloses the preparation of an antibacterial powder that can be used as an additive for plastic products. The powder comprises a core of inorganic material coated with an antibacterial metal or metal compound. The second coating consists of aluminum silicate, aluminum oxide, aluminum phosphate, silica, silicate, borosilicate, or a mixture of these substances. The porosity of the coating is intended to regulate the diffusion of the antibacterial active substance to prevent possible discoloration of the plastic used. A third coating of a hydrous metal oxide of aluminum, magnesium, zirconium, or rare earths is intended to reduce particle aggregation and improve particle dispersion in the plastic. The content of the antibacterial coating is 0.05 to 20 wt.% based on the carrier material. In the case of the second coating, the content is 0.5 to 20 wt.% based on the carrier material. The antibacterial powder can be added to various aliphatic or aromatic polymers.

[0007] European Patent No. 0270129 discloses a process for producing antibacterial powders based on zeolites and their use as additives for resins. Both natural and synthetic zeolites are used. The antibacterial function is based on the complete exchange of ammonium ions with the metal ions of silver, copper, zinc, mercury, tin, lead, bismuth, cadmium, chromium, and thallium. The metal content is 0.1-15% by weight silver and 0.1-8% by weight copper or zinc. The antibacterial zeolites are added to resins such as polyethylene, polypropylene, polystyrene, or PVC.

[0008] U.S. Patent No. 5,147,686 discloses the production of antibacterial powders using powdered titanium dioxide as a carrier material. The powder particles have a size of 0.01 μm to 3 μm. The particles are provided with an antibacterial active coating. The coating consists of copper, zinc, and their alloys, such as Cu-Zn, Cu-Ag, Cu-Sn, Cu-Al, Zn-Sn, Zn-Sn-Cu, Zn-Al-Cu-Mg, or similar alloys. The metal content is 0.001 to 35% by weight. The coating is applied by external currentless deposition, whereby the surface of the carrier particles is first activated with palladium or tin. In addition to its antibacterial properties, the powder is excellent as an additive in various media.

[0009] US Patent No. 2016 / 0369405 discloses a method for producing metal-coated particles in a liquid. Silicon, tin, germanium, gallium, lead, zinc, aluminum, or carbon particles are used as substrate particles coated with a metal in a reactor, where the metal is silver, copper, platinum, palladium, iron, cobalt, rhodium, nickel, vanadium, ruthenium, iridium, or gold. A reducing agent, such as ascorbic acid, is used to initiate the plating reaction. In particular, the production and use of silver-coated silicone particles is described.

[0010] Materials incorporated into products or materials in particulate form to ensure or enhance desired product properties are also designed as hybrid systems with different surface compositions and structures to integrate them into other materials and impart their specific particle properties in a desired manner. Therefore, multi-component hybrid particle systems must be specifically tailored to the desired material and required material properties through the correct selection of particle materials, particle sizes and structures, and additionally applied layer systems, or through chemical post-treatment of one or more components of the hybrid particle system. This also applies to microparticle systems with antibacterial properties, which are intended to introduce these antibacterial properties into products or materials. However, there is a risk that their desired core antibacterial properties, namely, antibacterial effect, may be weakened or even lost during particle processing or particle-material integration. Summary of the Invention [Means for solving the problem]

[0011] The objective of the present invention is to develop an antimicrobially active particulate hybrid material that can maintain its antimicrobial properties even after processing, material integration, and / or as an additive in products.

[0012] According to the present invention, the objective is solved by a hybrid material of the above type, in which the first metal comprises at least one semiconductor compound of at least one transition metal element exhibiting multiple oxidation states and enabling oxidation state change via catalytically active centers; the second metal comprises at least one conductive silver semiconductor; both metals establish a half-cell that is short-circuited in the presence of water and oxygen, resulting in the development of antibacterial, antiviral, and / or fungicidal effects; and the carrier material comprises a substance and / or coating material and at least one material compatible with their use. Overall, therefore, the present invention provides a hybrid, adaptable particulate multi-component system of different materials that can transfer its broad-spectrum antibacterial effect (for simplicity, effectiveness against bacteria, viruses, fungi, and other microorganisms will hereinafter be referred to as "antibacterial") to a wide variety of materials, substances, and / or coating materials without losing its antibacterial properties in the molding process, material integration, or ready-to-use product. The material components, particularly the carrier material, required for the molding process or material integration and use of the final antibacterial product are selected so as not to adversely affect, but rather enhance, the antibacterial properties of the hybrid particulate system. Furthermore, the hybrid material according to the present invention is an antibacterial active particulate system that can be tailored via the hybrid particle structure and is suitable for use in different products or primary materials or substances and / or coating materials. In this regard, the hybrid material according to the present invention can be integrated into substances and / or coating materials, for example. The combination with the hybrid particle system imparts antibacterial properties to the product or primary material, and the carrier material comprises at least one material selected, designed, and / or modified so that the hybrid material according to the present invention is optimally adapted to the substance and / or coating material and its use. Thus, in addition to maintaining the antibacterial effect, a further advantage of the hybrid material according to the present invention is that it can be specifically adapted to the material, substance, and / or coating material, as well as the required material properties and its desired application, for example, by the precise selection of the particle material, particle size and structure, and additionally applied layer system, or by chemical post-treatment of one or more components of the hybrid particle system.

[0013] According to the present invention, two metals with high chemical stability and different electrochemical potentials are deposited on a support material. These metals are preferably d-group transition metals, preferably noble metals. The metal combination according to the present invention is deposited on the support material so that both metals are in conductive contact with each other and are distributed on the surface of the support material in the form of multiple nano- or microgalvanic elements short-circuited via an aqueous phase. Therefore, the present invention advantageously includes an antibacterial active metal coating, each consisting of a semiconducting catalytically active transition metal compound (galvanic element half-cell I) and a semiconducting sparingly soluble silver compound (e.g., silver oxide, silver hydroxide, silver sulfide, silver-halide compounds, or combinations thereof; galvanic element half-cell II), both of which are in direct conductive contact with each other. The transition metal element in the first half-cell is selected to have several oxidation states, thus enabling (relatively easy) oxidation state changes via catalytically active centers. Therefore, particularly suitable half-cells are those with multiple valences in which highly reversible redox reactions can occur over a wide potential range. The high catalytic activity of such half-cells for oxygen reduction is due to the facile change of oxidation state and the easy exchange of oxygen, which occurs preferentially at the active centers on the semiconductor surface. In this process, only the valence of the transition metal element changes, resulting in the actual redox reaction. Therefore, transition metal compounds are neither consumed nor formed; only the oxidation state changes. Transition metal compounds bind to molecular oxygen, allowing it to catalytically reduce it. Therefore, the presence of multiple valencies is a prerequisite for catalytic activity and redox reactions. Therefore, the formation of transition metal compounds is not necessary. Special metal oxides or metal sulfides and sparingly soluble silver compounds exhibit catalytic properties, electrical conductivity, and high stability in water. With the appropriate combination of materials, two metals come into electrical contact with each other, have different electrochemical potentials, and thus form a galvanic cell. When this cell is short-circuited through the aqueous phase, a high electric field strength is generated due to the small distance (in the nm or μm range) between the two contacting metals. This significantly contributes to germ elimination. Redox reactions occur at both electrodes of the microgalvanic element, each killing microorganisms.In the first half-cell (cathode), molecular oxygen is reduced to oxygen radicals, which then have a toxic effect on microorganisms, and in the second half-cell (anode), electrons are transferred from the microorganisms to the silver semiconductor, thereby destroying them by oxidation.

[0014] The electrochemical potential difference of the transition metals of the hybrid system deposited on the support material is thereby adjusted so that they can reduce oxygen present in a humid environment by a redox process and form antibacterial active oxygen radicals.The hybrid antibacterial particle system according to the present invention, whose antibacterial effect is based not on the release of biocides or metal ions but on the catalytically assisted generation of oxygen radicals in the combination of noble metals, preferably silver oxide / ruthenium oxide and / or silver chloride / ruthenium oxide, does not change its composition even with long-term antibacterial use and, unlike biocides or oligodynamic metals, does not require a depot or device to regulate the release of biocides or metal ions.

[0015] The two metals (half-cells) can be applied, for example, as a layer system on the surface of a particulate support (support material), with one layer of one metal at least partially above the other. In this case, the respective upper layers can be porous (especially nanoporous) or microcracked, especially in the form of clusters, onto which the other metal is applied or deposited, allowing aqueous solutions or moisture to access both half-cells and short-circuiting the galvanic elements. However, alternatively or additionally, the two metals (half-cells) can also be applied to the surface of the particulate support (support material), for example, in the form of individual particles. These can be, for example, bimetallic particles containing both metals and / or metallic particles each containing only one of the two metals. The latter can be applied sequentially, i.e., first particles of the first metal, then particles of the second metal (or vice versa), or simultaneously as a mixture of particles of both metals, so that they are in conductive contact with the support material. The particles can be applied to the support material in a single layer (located adjacent to each other) and / or at least partially in multiple layers (located on top of each other).

[0016] Unlike biocides and oligodynamic metals, which must release toxic substances into the environment to be effective, only water is ultimately produced from the oxygen radicals formed when the hybrid material of the present invention is used. Because the metal combination is a catalytically supported system, its antimicrobial effect advantageously depends only on the active surface and not on the amount and rate of their leaching, as is the case with biocides or oligodynamic systems (silver, copper, and zinc or their salts or compounds).

[0017] In an advantageous embodiment of the present invention, a carrier material is provided comprising at least one material selected from the group consisting of cellulose, glass, zeolite, silicate, metal or metal alloy, metal oxide (e.g., TiO), ceramic, graphite, and polymer. The hybrid material of the present invention can be selected based on the requirements for integration with other materials and the specific application. For example, temperature resistance when incorporated into plastics (e.g., silver particles as a carrier), water absorption / absorption (e.g., cellulose as a carrier), magnetic particles (iron particles as a carrier) for analytical or manufacturing applications in devices where particle removal is only possible externally with a magnet, cellulose integration in the lyocell process where cellulose doped with the present hybrid material is dissolved in an organic cellulose solution to finely distribute the hybrid material particles in a cellulose slurry from which cellulose filaments can be spun, or color design (e.g., white: cellulose as a carrier). Surprisingly, in one embodiment of the antibacterial hybrid system of the present invention, the selection of cellulose as a carrier material offers new manufacturing possibilities for antibacterial textile fibers and films.

[0018] For example, cellulose (C) and its derivatives, such as microcrystalline (MCC) or nanocrystalline cellulose powder (NCC), can be used as carrier materials, offering numerous inherent properties that support the antibacterial effect of hybrid particle systems, such as their hydrophilicity and high water-binding capacity, which remains approximately 5–8% in the dry state. Cellulose fibers can be varied not only in fiber length but also in fiber cross-section, which can significantly increase the fiber cross-sectional area. Therefore, in addition to "standard cellulose," which has a cloud-shaped cross-section, fibers with star-shaped (trilobal) and letter-shaped (umberto) cross-sections are also available. The cellulose carrier surface can also be significantly increased by so-called bacterial cellulose (BC), due to its tissue-like micro-network structure. BC is also popular in medical applications due to its increased water absorption capacity.

[0019] Cellulose is the most abundant biopolymer on Earth, with an annual production rate of 1.5 trillion tons, making it the world's most important renewable raw material. It is used not only in the textile, paper, and building materials industries, but also in the medical field. The widespread use of cellulose materials, especially in medical applications, has led to the development of antibacterial cellulose particles. Cellulose itself does not possess antibacterial activity that could prevent infections. Most previous research on the production of antibacterial cellulose has focused on incorporating biocidal nanosilver particles onto or within cellulose fibers via various deposition processes. Surprisingly, the present invention has successfully deposited not only silver but also ruthenium onto cellulose in such a way that they adhere. In this regard, the method of the present invention achieves catalytically supported oxygen radical formation on the silver-ruthenium precipitate, which is also imparted to the cellulose support.

[0020] A further advantageous embodiment of the present invention provides that the hybrid material is modified with an organic polymer, preferably polyethylene glycol (PEG), polydopamine and / or chitosan, and / or ascorbic acid or an ascorbic acid derivative. In this context, modification can be achieved, for example, by pretreating the support material before applying the metal and / or by post-treating the hybrid material after applying the metal, in order to facilitate coating. In this way, certain properties of the product (material and / or coating material) doped with the hybrid material according to the invention can be modified or improved. For example, the flowability and / or dispersibility of particles or powders can be specifically adjusted by post-treating the hybrid material, for example, with polydopamine or propylene glycol (PG).

[0021] In an advantageous embodiment of the present invention, it is further provided that the strength of the antibacterial effect can be specifically adjusted by adjusting the amount of at least one of the two metals and / or the proportion of both metals on the particle surface. Thus, the antibacterial strength of a selected antibacterial hybrid material can be adjusted not only by changing the amount of particles, but also by changing its structure. The hybrid system according to the present invention can be specifically adjusted in terms of the strength of its antibacterial effect (in many cases, the highest effect is not desired, and adjustment is made by a growth curve), as well as the requirements for use or integration with other material(s), and the specific application of use. For example, the thickness of the at least one metal layer can be adjusted by changing the coating process. For example, the shape of the support material and / or a reduction process during coating can be used to selectively influence the structure of the metal layer. Furthermore, the strength of the antibacterial effect of the hybrid material according to the present invention can be specifically adjusted, for example, by using a specified amount of at least one metal (e.g., the proportion (wt%) of the metal in the total hybrid material).

[0022] In another advantageous embodiment of the present invention, there is provided a transition metal element which is at least one metal from the group consisting of ruthenium, iridium, vanadium, manganese, nickel, iron, cobalt, cerium, molybdenum, and tungsten.

[0023] A particularly advantageous embodiment of the present invention provides a transition metal compound of a first metal containing ruthenium in one or both of oxidation states VI and IV. Ruthenium is a noble metal with multiple oxidation states, and its different valences can, for example, form different ruthenium oxides. Surface redox transitions such as Ru(VIII) / Ru(VI), Ru(VI) / Ru(IV), Ru(IV) / Ru(III), and possibly Ru(III) / Ru(II) are responsible for the high catalytic activity of mixed ruthenium compounds and their good electrical conductivity. The highly significant catalytic and electrocatalytic properties of ruthenium compounds depend on the variation in oxidation state. For example, antibacterial activity is particularly high in compositions according to the present invention that contain ruthenium(VI) oxide in the first half-cell.

[0024] Thereby, the transition metal compound of the first metal may include at least one corresponding metal oxide, metal oxyhydrate, metal hydroxide, metal oxyhydroxide, metal halide, and / or at least one metal sulfide of the transition metal element.

[0025] In an advantageous embodiment of the present invention, there is further provided a silver semiconductor comprising at least one silver oxide, silver hydroxide, silver halide or silver sulfide, or a combination of silver and a corresponding silver compound (e.g., metallic silver having a silver compound such as silver oxide or silver chloride on its surface).

[0026] In a further advantageous embodiment of the present invention, particles are provided that have a spherical or polyhedral shape and an average diameter of up to 100 μm, preferably up to 50 μm, and particularly up to 5 μm. For example, such spherical particles may have an average diameter of 0.1 to 70 μm, preferably 0.1 to 50 μm or 0.1 to 10 μm, and particularly 1 to 5 μm. Alternatively or additionally, the particles may have a fibrous shape and an average length of up to 1 mm, preferably up to 100 μm, and particularly up to 75 μm or 60 μm. For example, such elongated particles may have an average length of 0.1 to 100 μm, preferably 0.1 to 50 μm or 0.1 to 10 μm, and particularly 0.1 to 1 μm. Particle size and shape play an important role, for example, in nozzle problems during spinning of polymer threads (e.g., fine silver particles) or when a large surface area is required (e.g., due to different cellulose fiber cross sections or fine silver particles). Since the antimicrobial effect of the hybrid material according to the invention is based on a catalytic process at the particle surface, the particle efficiency increases as the particle surface fraction increases relative to the particle volume, and therefore the particle efficiency is particularly advantageous for smaller particle sizes.

[0027] The present invention relates to a hybrid material having antibacterial activity, in particular to a method for producing said hybrid material, comprising the following steps: a) providing or producing a particulate support material; b) at least partially applying a first metal onto a support material; c) at least partially applying a second metal onto the support material and / or the first metal, wherein both metals are applied in conductive contact with each other at least on their respective surfaces; The problem is further solved by a method comprising:

[0028] In principle, all of the materials mentioned at the beginning can be used as carrier materials, preferably cellulose, metals, metal oxides (e.g., TiO2), glass, ceramics, graphite, and polymers. In certain embodiments, the antibacterial hybrid system comprises a magnetizable particle core. For example, an antibacterial coating may be deposited on a ferromagnetic core (e.g., nickel, iron, or cobalt powder). Such an antibacterial hybrid system is required, for example, when particles require complete removal from difficult-to-access reaction or analytical vessels after use. The antibacterial magnetizable particle hybrids can be pulled from outside the reactor using a strong magnet to an accessible location in the reactor where they can be removed.

[0029] Preferably, a first metal containing at least one conductive silver semiconductor is applied to the support material. A second metal is also applied to the support material and / or the first metal, the second metal having multiple oxidation states and containing at least one transition metal element that allows a change in oxidation state via a catalytically active center. Alternatively, a first metal containing at least one transition metal element that has multiple oxidation states and allows a change in oxidation state via a catalytically active center can be applied to the support material. In this case, a second metal is also applied to the support material and / or the first metal, the second metal containing at least one conductive silver semiconductor. In both alternatives, the second metal is applied to the support material and / or the first metal in a permeable manner so that the two metals are in conductive contact with each other at least on their respective surfaces and with the electrolyte, thereby developing an antibacterial effect (see above).

[0030] For example, silver can be chemically and reductively deposited on a support material (e.g., glass beads) to produce the hybrid material according to the present invention. Silver nitrate (AgNO3) is preferably used as the silver salt. Various reducing agents, such as aldehydes, ascorbic acid, metal hydrides (preferably sodium borohydride), hydrazine and / or hydrazinium salts, and / or hydroxylamine and / or hydroxylammonium salts, can be used as reducing agents. When cellulose is used as the support material, ascorbic acid is preferably used as the reducing agent. Commercially available silver-coated support materials (e.g., pre-silver-coated glass beads) are available, and if used, this first step can be omitted. Ruthenium, for example, can then be applied to the silver layer by chemical reduction. For ruthenium coating, the silver-coated support material (e.g., glass beads) is dispersed in an alkaline solution under vigorous stirring. A solution of ruthenium(III) chloride and sodium borohydride is then added as a reducing agent.

[0031] An advantageous embodiment of the method according to the invention provides that at least one of the two metals is applied onto the support material and / or the respective other metal in the form of clusters, nanoporosity, microcracks and / or single particles.

[0032] In an advantageous embodiment of the method according to the invention, after step a) and / or step c), the carrier material and / or metal are further modified with an organic polymer, preferably polyethylene glycol, polydopamine, and / or chitosan, and / or ascorbic acid or an ascorbic acid derivative. Consequently, the hybrid material can be modified by pretreating the carrier material before applying the metal and / or by post-treating it after applying the metal, for example, to facilitate coating. In this way, specific properties of the product (material and / or coating material) doped with the hybrid material according to the invention can be modified or improved. According to the invention, for example, a carrier material with an antibacterial metal coating, with or without a chemically produced compound layer (see below), can be modified to optimize the properties of the hybrid material. This relates, for example, to flowability, dispersibility, or long-term stability. According to the invention, despite the modification of the hybrid particle system, its antibacterial properties are maintained or even improved.

[0033] In a further advantageous embodiment of the method according to the invention, a linking layer is formed on at least one metal, comprising at least one metal compound of the corresponding metal selected from the group consisting of halides, oxides, and sulfides. To enhance functionality, the two metals are activated with a chemically stable compound of the metal. For this purpose, a linking layer is formed on the metal, which may consist of, for example, a halide, oxide, or sulfide. The effect of the post-treatment of the particulate surface can be determined or adjusted accordingly, for example, using appropriate microbiological methods or measurement procedures such as growth curves.

[0034] In an advantageous embodiment of the method according to the present invention, the strength of the antibacterial effect can be specifically adjusted by adjusting the amount and / or ratio of at least one of the two metals on the surface of the particle. For example, the strength of the antibacterial effect of the hybrid particle system can be controlled by appropriately selecting the deposition conditions of the two metals on the surface of the carrier material, and the area ratio of the two metals on the hybrid surface can be changed relative to each other. The surface composition required for the desired antibacterial effect of the hybrid particulate material of the present invention can be determined by appropriate microbiological methods, such as growth curves, based on variations in particle composition and structure.

[0035] In a further advantageous embodiment of the method according to the invention, it is provided that the respective metals are applied sequentially or simultaneously by electrochemical deposition, chemical reduction deposition, electrophoretic coating, baking, PVD, CVD and / or sol-gel processes. In this connection, the two metals (half-cells) can also be deposited, for example, in the form of individual particles on the surface of the support material. The particles can be applied to the support material, for example, sequentially, i.e., as first particles of the first metal and then particles of the second metal (or vice versa), or simultaneously as a mixture of particles of both metals (or possibly in the form of bimetallic particles).

[0036] In calcination, a thermally decomposable compound containing the desired transition metal (usually anhydrous) is intensively mixed in an alcohol (e.g., ethanol or isopropanol), applied to the surface to be coated, and then thermally decomposed at high temperatures (e.g., 200-500°C) in the presence of air. This process allows any desired composition of the two half-cell metals to be prepared by mixing the two metal salts to obtain the appropriate oxide compound. Examples of readily decomposable ruthenium compounds include RuCl3 (general halides).

[0037] In a particularly advantageous embodiment of the present invention, it is further provided that the application of the second metal to the support material and / or the first metal includes at least one step with a strong oxidizing effect. For example, ruthenium / ruthenium oxide can be applied in a two-step process, in which ruthenium is first oxidized in the first step, and only in the second step is the reduction of ruthenium oxide to ruthenium and RuOx achieved. Unlike the direct, one-step reduction of Ru(III) ions with a strong reducing agent, this indirect, two-step process relies on the oxidation of Ru(III) ions to ruthenium(VIII) oxide (RuO4). RuO4 is a strong oxidizing agent that is converted to ruthenium(IV) oxide by a suitable reducing agent, coating the support material with a layer of ruthenium(IV) oxide. For example, the formation of ruthenium(VI) oxide can be achieved by both electrochemical and PVD deposition of ruthenium, if the ruthenium deposition includes a process step with a strong oxidizing effect.

[0038] A further advantageous embodiment of the present invention provides that after applying both metals, a thermal post-treatment is carried out to adjust the specific oxidation state: if the support material is heat-resistant, the applied oxide metal coating or metal compound can be subjected to thermal oxidation or reduction in a suitable atmosphere to set the specific oxidation state.

[0039] The present invention further relates to a hybrid material having antibacterial activity produced by the above method.

[0040] The present invention also relates to the use of the hybrid material according to the present invention for joint application with any material, substance and / or coating material, preferably lacquer, paint, plaster, polymer and / or cellulose. In this regard, the hybrid material may be associated with the material, substance and / or coating material in any manner. For example, the material, substance and / or coating material may be coated or blended with the hybrid material particles. Preferably, the hybrid material particles of the present invention are incorporated into the material, substance and / or coating material.

[0041] Despite its catalytic activity, the cellulose-silver-ruthenium particle additive does not significantly affect the decomposition temperature of the solvent used in the lyocell process (N-methylmorpholine N-oxide (NMMO)), and therefore can be processed in the lyocell process. Surprisingly, the hybrid cellulose-silver-ruthenium particle variant of the hybrid material according to the present invention offers the possibility of producing antibacterial cellulose fibers and cellulose films based on the antibacterial hybrid system according to the present invention with the help of innovative and environmentally friendly lyocell technology. In the lyocell process, the carrier material cellulose dissolves in NMMO, releasing silver-ruthenium particles that are deposited on the cellulose fibers uniformly distributed in the cellulose-containing solvent. As a result, antibacterial lyocell fibers can be produced therefrom, not only for the textile industry, but also for nonwovens and other technical applications, such as packaging films.

[0042] The present invention also relates to microparticles, particularly bimetallic particles, for forming antibacterial active powders, comprising particles of a first metal coated with a cluster-shaped, nanoporous, and / or microcracked layer containing a second metal, the first metal particles having an average diameter of up to 50 μm, preferably up to 10 μm. A specific embodiment of the present invention is established when one of the two active components (metals) of the hybrid system simultaneously serves as both the surface and the support material. For economic reasons alone, this only applies to very small noble metal support particles (e.g., 0.1-50 μm, preferably less than 5 μm). This hybrid system variant is optional in processing operations (e.g., into certain plastics) for integrating the hybrid antibacterial particle system according to the present invention, which must be carried out at high temperatures. For this purpose, the metal particles used as the support material must be appropriately small so that the cost of the hybrid particle system can be overcompensated by a correspondingly smaller amount of noble metal due to a more favorable surface-to-volume ratio.

[0043] In an advantageous embodiment of the microparticles according to the invention, it is provided that the first metal is silver and the second metal is a metal selected from the group consisting of ruthenium, iridium, vanadium, manganese, nickel, iron, zinc, cobalt, cerium, molybdenum, and tungsten, or the first metal is a metal selected from the group consisting of ruthenium, iridium, vanadium, manganese, nickel, iron, zinc, cobalt, cerium, molybdenum, and tungsten, and the second metal is silver.

[0044] The present invention also relates to a method for preparing microparticles, in particular bimetallic particles, with antibacterial activity, comprising the following steps: a) dispersing silver particles having an average diameter of 50 μm or less in an alkaline solution; b) adding a ruthenium(III) chloride solution and a reducing agent to the dispersion from step a); c) separating the microparticles from the dispersion according to step b); Includes.

[0045] An advantageous embodiment of the process according to the invention provides that the reducing agent is sodium borohydride, hydrazine and / or hydrazinium salts, and / or hydroxylamine and / or hydroxylammonium salts.

[0046] The present invention further includes microparticles, particularly bimetallic particles, for forming antibacterial powders prepared by the above-described methods.

[0047] The microparticles or bimetallic particles according to the present invention can be advantageously used with any material, substance, and / or coating material, preferably lacquer, paint, plaster, polymer, and / or cellulose. In this regard, the microparticles may be associated with the material, substance, and / or coating material in any manner. For example, the material, substance, and / or coating material may be coated or blended with the microparticles. Preferably, the microparticles are incorporated into the material, substance, and / or coating material.

[0048] Preferably, the particulate or bimetallic particles according to the invention are a component of the hybrid material according to the invention, the support material being at least partially coated with the particulate or bimetallic particles.

[0049] The microparticles or bimetallic particles according to the invention can therefore be used in an advantageous manner to produce the hybrid material according to the invention by applying them to a support material, which can be applied in a single layer (side by side) and / or at least partially in multiple layers (overlapping one another).

[0050] The particulate materials of the present invention are suitable, for example, for providing coatings and paints, plasters, polymers, textiles, and packaging materials with antibacterial properties. In principle, a wide range of materials can be used as carrier materials, such as cellulose, metals or metal oxides (e.g., TiO), ceramic / mineral, or polymeric materials. Hybrid antibacterial particle systems are particularly advantageous when, in addition to the active ingredient, other components of the hybrid system can contribute additional favorable properties that can support or improve the effectiveness, processing, or integration into the desired semi-finished or final product.

[0051] "Particle", "particulate" or "particulate" in the sense of the present invention refers to a single particle-shaped entity as a whole, drawn from other particles and its surroundings. In this context, all possible particle shapes and sizes, regardless of geometric shape and mass, are included within the scope of the present invention. Particles can be characterized, for example, by their shape, weight, volume and / or size (e.g., length, diameter, circumference).

[0052] A "half-cell" in the sense of the present invention refers to a part of a galvanic element that, in combination with at least one further half-cell, forms a galvanic element. In this context, a half-cell comprises a metal electrode that is at least partially located in an electrolyte.

[0053] A "galvanic element" in the sense of the present invention refers to the combination of two different metals, each forming an electrode (respectively an anode and a cathode) in a common electrolyte. When the two metal electrodes are in direct contact with each other or are conductively connected to each other via an electronic conductor, the less noble metal with a lower redox potential (electron donor, anode) donates electrons to the more noble metal with a higher redox potential (electron acceptor, cathode), which subsequently initiates the redox process at the electrode.

[0054] An "electrolyte" in the sense of the present invention refers to a compound (eg, ions in an aqueous solution) that conducts electric current under the influence of an electric field by the directional movement of ions.

[0055] "Substance" in the sense of the present invention refers to the material from which parts, components, structural elements or assemblies of an article or product are made. In particular, the term "substance" includes, but is not limited to, parts made of at least one polymer (plastic; including films as packaging materials), textiles (natural and / or synthetic textile fibers; woven, knitted, crocheted and braided fabrics), nonwovens, metals, glasses and ceramics.

[0056] "Coating material" in the sense of the present invention refers to a material or substance with which an object or product is or can be at least partially covered. The coating material may be applied to the object or product in one or more (preferably thin) layer(s). In particular, the term "coating material" includes, inter alia, liquid or pasty coating materials such as lacquers, paints and plasters, as well as solid coating materials such as powders and films.

[0057] "Metal" in the sense of the present invention refers to atoms of chemical elements of the periodic table of elements (all elements except non-metals) that form a metal lattice by metallic bonds, thereby referring to a macroscopically homogeneous material characterized, inter alia, by high electrical and thermal conductivity. The term "metal" also includes at least two different metals, metal compounds such as metal oxides, metal oxyhydrates, metal hydroxides, metal oxyhydroxides, metal halides and metal sulfides, as well as alloys containing a combination of metals and the corresponding metal compounds.

[0058] A "layer" or "layered" in the sense of the present invention refers to a two- or three-dimensional structure having a horizontal extension and bounded by at least two surfaces, a layer bottom and a layer top. In this context, a layer may comprise a consistent material or substance and / or particles that are at least partially in contact with each other. In the sense of the present invention, a layer may be homogeneous, heterogeneous, continuous (i.e., uninterrupted), clustered, nanoporous, and / or microcracked. "Coated" in the sense of the present invention is a material, particle, or other object (see above) if at least part of its (external or internal) surface is provided with a "layer."

[0059] The invention is explained in more detail by the following figures and examples. [Brief explanation of the drawings]

[0060] [Figure 1] 1 is a schematic diagram illustrating an exemplary embodiment of a hybrid material according to the present invention. [Figure 2] 1 shows photographic images of different antibacterial variants of hybrid materials according to the present invention prepared on silver-coated glass beads S3000S from Potters Industries Inc. having an average diameter of about 40 μm. [Figure 3]REM images of silver-coated glass beads S3000S from Potters Industries Inc. at 300x magnification (top left) and 10,000x magnification (top right). Ruthenium-coated samples are shown at 10,000x magnification: Samples 513 (center left), 514 (center right), 515 (bottom left), and 516 (bottom right). [Figure 4] 4 is a bar graph showing the catalytic formation of hydrogen peroxide on the surface of particulate antimicrobial hybrid materials 513, 514 and 515 according to FIG. 3. [Figure 5] Figure 1 shows a photographic image of the zone of inhibition test. A suspension culture of Escherichia coli (E. coli) (DSM498) was plated on an agar plate. The silver-coated glass particles S3000S and the antibacterial hybrid materials 513, 514, and 515 were inoculated onto the agar as samples according to Figure 3 and incubated at 37°C for 18 hours. The samples were then added to the agar plate. [Figure 6] 4 shows growth curves of MRSA cultures (source: Robert Koch Institute) in the presence of glass particles S3000S and antibacterial hybrid materials 513, 514 and 515 according to FIG. 3. [Figure 7] 1A-1D are photographic images of exemplary embodiments of hybrid materials according to the present invention: a) uncoated cellulose powder; b) coated antimicrobial cellulose powder with a silver content of 20% by weight and a ruthenium content of 1% by weight; c) distribution of the two metals on cellulose fibers; and d) zone of inhibition test powders prepared according to the present invention. [Figure 8] 8 shows growth curves of MRSA cultures (source: Robert Koch Institute) in the presence of hybrid materials (powder) according to the invention shown in Figure 7. (a) Determination of the minimum inhibitory concentration; and (b) Dependence of the antibacterial efficiency of cellulose particles on the ruthenium content. [Figure 9]Figure 1 shows photographic images, bar graphs and tables relating to the antimicrobial efficacy of cellulose films or yarns produced by the Lyocell process: a) cellulose films; b) Zone of inhibition test for the antimicrobial activity of cellulose filaments produced according to the present invention against Escherichia coli (E. coli) (DSM 498); and c) Antimicrobial activity of particulate cellulose-based silver-ruthenium hybrid (720b) ​​against Staphylococcus aureus (S. aureus) (DSM 799). [Figure 10] 1 is a graphical representation (curve) of a viral plaque assay for the efficacy of one embodiment of a hybrid material according to the present invention against SARS-CoV-2 and feline coronavirus (FCoV): (a) feline coronavirus (FCoV); and (b) SARS-CoV-2. [Figure 11] 1A-1C are photographic images of exemplary embodiments of hybrid materials (microparticles or antibacterial powders) according to the present invention. a) Uncoated silver powder; b) Antibacterial powder coated according to the present invention; c) REM image of powder particles at 100,000x magnification. d) Zone of inhibition test for antibacterial activity of microparticles or powders according to the present invention. [Figure 12] FIG. 11b shows the growth curve of MRSA on the microparticles according to the invention shown in FIG. [Figure 13] 10A-10D are photographic images of further exemplary embodiments of catalyst-based hybrid materials (microparticles or antibacterial powders) according to the present invention: a) powder after filtering, washing, and drying; b) black powder applied with mortar; c) REM image of powder particles at 100,000x magnification; and d) Zone of inhibition test for antibacterial activity of microparticles or powders according to the present invention. [Figure 14] FIG. 14 shows the growth curve of the fine particles or powder according to FIG. 13. [Figure 15] 1A-1C are photographic images of several samples of a commercially available facade paint to which increasing concentrations (0.1%, 0.5% and 1.0% by weight) of an exemplary embodiment of a hybrid material according to the present invention prepared on glass particles have been added. [Figure 16]10A-10C are photographic images of several samples of a commercial antifouling paint to which increasing concentrations (2.0 wt %, 4.0 wt %, and 8.0 wt %) of another exemplary embodiment of a hybrid material according to the present invention prepared on cellulose powder have been added. [Figure 17] 1A-1C are photographic images of an Ultramid C33 sample containing 1 wt. % of an exemplary embodiment of a hybrid material of the present invention prepared with commercially available silver powder: a) granules; b) plate; and c) zone of inhibition test of the sample against Escherichia coli (E. coli). [Figure 18] FIG. 1 shows (a) a photographic image of fibers of polyamide containing 3 wt. % of an exemplary embodiment of a catalyst-based hybrid material of the present invention and (b) a bar graph of the antimicrobial efficacy of these fibers. [Figure 19] Figure 1 shows photographic images of an antibacterial hybrid material prepared according to the present invention, the core of which consists of ferromagnetic iron powder (a and b), and a bar graph (c) showing the lysis of Gram-positive B. subtilis bacteria by this hybrid material. [Figure 20] 1A-1C are photographic images of exemplary embodiments of hybrid material according to the present invention, uniformly distributed in water by vigorous stirring: a) particles of hybrid material without post-coating; and b) particles of hybrid material subsequently treated with dopamine hydrochloride solution (2 mg / ml) and phosphate buffer (0.1 M, pH 8.5) at room temperature. [Figure 21] 1 is a photographic image of a zone of inhibition test for the antimicrobial efficacy of an exemplary embodiment of a cellulose-based hybrid material according to the present invention, the efficacy of which is not compromised by post-treatment. [Figure 22] Photograph images of cellulose-based antimicrobial hybrid materials incorporated into siloxane to impart antimicrobial activity: a) siloxane-coated H2084 and H5055; and b) antimicrobial assay results of Escherichia coli (E. coli) on agar with polypropylene platelets coated on one side with siloxane. [Figure 23]FIG. 1 shows the growth curves of MRSA bacteria using two ruthenium / ruthenium oxide / / silver / silver chloride (Ru / RuOx / / Ag / AgCl) powders (AP383 and AP823) prepared by different ruthenium deposition processes for different powder amounts. [Figure 24] FIG. 1 shows XPS surface analysis (Ru 3d spectra) of electroplated Ru / RuOx / / Ag / AgCl powder samples 825 and 392 and Ru / RuOx / / Ag / AgOx PVD coatings on polyethylene films (samples Ru and RuOx). [Figure 25] FIG. 1 shows O1s spectra of samples 825, 392, Ru, and RuOx. DETAILED DESCRIPTION OF THE INVENTION

[0061] According to the present invention, a particulate hybrid material is produced based on a core material (support material). For example, a first closed layer containing one of the two electrode metals according to the present invention is first applied to the core material (cellulose, metal, glass, ceramic, graphite, polymer). Subsequently, a second electrode metal is applied to the core material and / or the first electrode layer as a thin, open, cluster-shaped, porous or microcracked second layer. These coatings can be applied by conventional electrolytic processes, chemical reduction processes, or vapor deposition. Preferably, a chemical reduction process is used, in which the metal is deposited on the selected support material by chemical reduction. Suitable reducing agents include aldehydes, ascorbic acid, hydrazine, hydroxylamine, or metal hydrides. To prevent the reducing agent from depositing metal ions already in the solution rather than on the particle core, which would decompose the solution and result in metal loss, a suitable inhibitor known to experienced electroplaters can be added to the electrolyte. For ruthenium deposition, for example, ethylenediamine can be added as a suitable inhibitor. Depending on the reducing agent used, the surface of the support material must be activated with a catalyst. No additional activation is required for this combination since the silver causes the decomposition of the sodium borohydride.

[0062] The deposition of two metals onto a support material can be carried out, for example, in a two-stage process, since both metals can be galvanically deposited from electrolytes with different compositions. Preferably, chemical reduction metal deposition is carried out batchwise, ensuring that the amount of metal contained in the electrolyte is completely deposited on the particle core. Verification of complete electrolyte completion can be performed by classical analytical methods such as AAS or ICP, which is essential not only for quality control but also when precious metals are used as antibacterial coating materials. To achieve uniform and complete deposition of the metals on the particle core, the metered addition of the metal compounds, reducing agents, and other chemical additives to the reactor must be carried out simultaneously with high electrolyte transport, for example, by a stirrer or mixer (or kneader in the case of cellulose). Classical electrolyte control, such as temperature control or cooling and pH measurement, is important for quality assurance of hybrid antibacterial particles and process reliability.

[0063] Post-coating of the antimicrobial hybrid material is carried out in a separate reactor, for example, by adding, under uniform stirring, an aqueous solution containing reactants, such as halide- or sulfide-containing water-soluble compounds, ascorbic acid, chitosan, polyethylene glycol, polydopamine, to the metal surface of the hybrid system, where chemical reaction or chemisorption occurs on the surface of the metal on the hybrid material of the present invention.

[0064] Figure 1 shows a schematic representation of the structure of a particulate antimicrobial hybrid material, whose shape and size are largely determined by the particle core (1). The particle size is typically <50 μm, preferably <5 μm. For fibrous particles, the linear extension can be <1 mm, preferably <60 μm, preferably <1 μm, depending on the application.

[0065] A first substantially closed metal layer (2), preferably a silver layer, is applied to the core (1).

[0066] On top of the first layer (2) of the hybrid system, a second metal, preferably ruthenium, is applied as a very thin nanoporous layer (3). The first layer (2) and the second layer (3) on the core (1) are configured in such a way that oxygen from the humid environment is reduced at the cathodic part of the applied material on the hybrid surface, forming oxygen radicals.

[0067] The metal components of the first layer (2) and the second layer (3), respectively, can be converted to metal compounds (4), such as metal halides or metal sulfides, by chemical reaction on the surface, or can form oxide layers with oxidizing solutions, or can convert existing oxide layers to mixed oxide layers with altered valence. Alternatively, the hybrid layer system on the particle can be provided with a chemisorbed ascorbic acid layer (5).

[0068] The hybrid system can be further provided with a polymer layer (6) of chitosan, polyethylene glycol or polydopamine which does not inhibit the antibacterial effect.

[0069] Depending on the required property profile, the chemically reductively deposited metals and chemically applied inorganic or organic layers can be variably tailored in their lateral distribution, thickness and structure.

[0070] Figure 2 shows different antibacterial variants of the hybrid material according to the present invention prepared on silver-plated glass beads S3000S from Potters Industries Inc., with an average diameter of approximately 40 μm. Silver served as the anode material, on which ruthenium was deposited in different layer thicknesses as a catalytically active cathode material. For the ruthenium coating, the glass spheres were dispersed in an alkaline solution under vigorous stirring. A solution of ruthenium(III) chloride and sodium borohydride was then added as a reducing agent. Particles with different ruthenium layer thicknesses were prepared. The calculated average ruthenium layer thicknesses were approximately 0.4 nm for Sample 513, approximately 0.8 nm for Sample 514, and approximately 1.9 nm for Sample 515. The surfaces of the samples became slightly darker with increasing ruthenium layer thickness. Sample 515 exhibited a light brownish hue.

[0071] Figure 3 shows SEM images of chemically-reductively coated particles. Silver-coated glass particles S3000S are shown at 300x magnification (top left) and 10,000x magnification (top right). Additionally, a ruthenium-coated sample is shown at 10,000x magnification. Samples 513 (center left), 514 (center right), and 515 (bottom left) show very uniform coatings. The porous structure of the catalytically active ruthenium coating is evident for sample 516 (bottom right), which has an average coating thickness of approximately 9.4 nm.

[0072] Figure 4 shows the catalytic formation of hydrogen peroxide on the surface of particulate antimicrobial hybrid materials 513, 514, and 515. 50 mg of each bead was incubated in a solution of ferrous iron and xylenol orange on a shaker at 225 rpm for 1 hour. The iron(II) ions were oxidized with the formation of hydrogen peroxide. The resulting ferric iron ions immediately formed a colored complex with xylenol orange, the concentration of which was measured photometrically at a wavelength of 585 nm. As the thickness of the ruthenium layer increased, the concentration of hydrogen peroxide formed increased.

[0073] Figure 5 shows the determination of antibacterial efficiency of powder samples after zone of inhibition test. 750 μl of a suspension culture containing 1 / ml of E. coli (DSM498) was plated. The samples were plated on agar and incubated at 37°C for 18 hours. The silver-coated glass particles S3000S already showed moderate antibacterial activity. The antibacterial efficiency of powders 513, 514 and 515 was very high. No differences between these samples could be distinguished after the microbial agar test.

[0074] Figure 6 shows the growth curves of powders S3000S, 513, 514 and 515. 30 ml of MRSA culture (source: Robert Koch Institute) was adjusted to an optical density of 0.1 in an Erlenmeyer flask. Subsequently, 200 mg of each of the different samples was incubated in a shaking incubator at 37°C and 150 rpm. The optical densities (OD 600 ) was determined at 1-hour intervals. After this highly sensitive antibacterial assay, no inhibition of MRSA culture growth was measured for the silver-coated glass beads. As the thickness of the ruthenium layer on the beads increased, growth inhibition increased significantly. For sample 515, complete growth inhibition was observed for the selected powder weight. Therefore, the minimum inhibitory concentration (MIC) for this powder is 200 mg.

[0075] Figure 7 shows an antibacterial microparticle hybrid material prepared based on cellulose powder with an average fiber length of 60 μm. First, the cellulose powder was soaked in a silver nitrate solution. Then, the silver ions were reduced by adding ascorbic acid. A grayish-white silver-coated cellulose powder was obtained. The silvered cellulose powder was then dispersed in an alkaline solution with vigorous stirring. A solution of ruthenium(III) chloride and sodium borohydride was then added as a reducing agent. A dark gray powder was obtained, the color of which depends largely on the ruthenium content. Figure 7a shows the uncoated cellulose powder, and Figure 7b shows the coated antibacterial powder with a silver content of 20 wt% and a ruthenium content of 1 wt%. Figure 7c shows a 10,000x SEM image of the fiber surface, demonstrating the uniform distribution of the two metals on the cellulose fibers. Zone of inhibition tests in Figure 7d demonstrate that various batches of powder produced by this process have high antibacterial activity.

[0076] Figure 8a shows the determination of the minimum inhibitory concentration of antibacterial powder on coated cellulose by constructing an MRSA growth curve. A sample without added antibacterial powder served as the control. The minimum inhibitory concentration of the prepared powder was only 15 mg. Figure 8b shows that the antibacterial efficiency of the prepared cellulose-based antibacterial particles also depends on their ruthenium content. According to the determined growth curve, a ruthenium content of 0.2 wt% shows only slight inhibition of MRSA bacterial growth, whereas a ruthenium content of 1.0 wt% results in complete inhibition of growth. Again, a sample without added antibacterial powder served as the control. Each powder weighed 20 mg.

[0077] All hybrid silver-ruthenium particles on cellulose carrier materials exhibited antibacterial efficacy, but the strength of the antibacterial effect could again be differentiated based on the growth curves with MRSA bacteria. Table 1 shows that both the ruthenium content and the silver content (amount) affected the strength of efficacy against MRSA. Both metals could be used to control the antibacterial effect of the hybrid materials of the present invention with respect to the required strength. Table 1 shows the amounts of silver and ruthenium [wt%] analyzed for the entire hybrid material, and the respective antibacterial strengths are rated as (x+) according to the legend. In principle, if sufficient amounts are present, all material variants can ultimately exhibit complete antibacterial efficacy. Therefore, for measurements, since not all variants achieved complete MRSA kill, the particle amount was reduced until differentiation could be made. If 100% efficacy of a silver-ruthenium variant was still detectable with a lower weighting, it was classified as a particularly effective composition. Therefore, Table 1 shows the rating of the indicated variants according to weight. [Table 1]

[0078] Figure 9a shows an antibacterial cellulose film produced by the Lyocell process, which was produced by adding a cellulose-based antibacterial hybrid material produced according to the present invention to the Lyocell process. Similarly, antibacterial cellulose filaments can also be produced after the Lyocell process. Figure 9b shows the antibacterial effect of cellulose filaments produced according to the present invention against Escherichia coli (DSM 498) based on the inhibition zones formed around the thin filaments. Figure 9c shows significant antibacterial activity against Staphylococcus aureus (DSM 799) measured according to DIN EN ISO 20743 by adding only 3% of the particulate cellulose-based silver-ruthenium hybrid (720b) ​​to the cellulose spinning solution.

[0079] Figure 10 shows the effectiveness of the particulate antimicrobial hybrid material prepared according to the present invention against SARS-CoV-2 and feline coronavirus (FCoV), which are more difficult to inhibit. Testing was performed at FU Veterinary Medicine using a so-called plaque assay. The viral plaque assay determines the number of plaque-forming units (pfu) in a viral sample, which is a measure of the amount of virus. This assay is based on a microbiological method performed in Petri dishes or multiwell plates. Viral plaques form when a virus infects cells within a fixed cell monolayer. Virus-infected cells lyse, and the infection is transmitted to neighboring cells, where the infection-lysis cycle is repeated. The infected cell area forms a plaque (an infected area surrounded by uninfected cells) that can be visualized by light microscopy or visually. In Figure 10a, the plaque reduction assay shows that the cellulose-based antimicrobial particles prepared according to the present invention have an antiviral effect against feline coronaviruses even at a concentration of approximately 0.2 mg / ml (IC50: kills 50% of the virus). In the case of the antiviral effect of the antimicrobial cellulose-based microparticle hybrid material according to the present invention against SARS-CoV-2, shown in Figure 10b, the IC50 is even significantly lower at about 0.05 mg / ml. Therefore, the antimicrobial hybrid system according to the present invention is suitable for fighting viruses by incorporating the particles into paints, coatings, and plastics.

[0080] Figure 11 shows microparticles (antibacterial powders) prepared on silver particles according to the present invention, in which commercially available spherical silver powder with a particle size of 1 μm-100 μm was coated with ruthenium. The silver powder was dispersed in an alkaline solution under vigorous stirring. A solution of ruthenium(III) chloride and sodium borohydride was then added as a reducing agent. A dark gray powder with a ruthenium content of 3.2 wt% was obtained. Figure 11a shows the uncoated silver powder, and Figure 11b shows the coated antibacterial powder. Figure 11c shows an SEM image of powder particles at 100,000x magnification with a diameter of approximately 1 μm. The porous structure of the ruthenium coating is clearly visible. Figure 11d shows a zone of inhibition test demonstrating the high antibacterial efficiency of the microparticles or powders according to the present invention.

[0081] Figure 12 shows the growth curve of MRSA for antibacterial microparticles based on silver particles according to Figure 11b. The minimum inhibitory concentration of the particles is 20 mg. A sample without added antibacterial powder served as a control.

[0082] Figure 13 shows the catalyst-based microparticles (antibacterial powder) of the present invention. The silver powder used as the base was previously prepared by a chemical reduction process. Ascorbic acid was used as the reducing agent, and gum arabic was used as the inhibitor. The prepared silver powder was filtered, washed, and immediately coated with ruthenium after filtration. Again, a solution of ruthenium(III) chloride and sodium borohydride was added as the reducing agent. Figure 13a shows the powder after filtration, washing, and drying. Larger, hard, golden particles were formed. These were then crushed. Figure 13b shows the black powder coated with mortar. The particle size of the powder varied from 0.1 μm to 5 μm. The ruthenium content was 3.2% by weight. Figure 13c shows an SEM image of the powder particles at 100,000x magnification. The diameter is approximately 0.7 μm.

[0083] Figure 14 shows the growth curve of the microparticles or powder according to Figure 13. The minimum inhibitory concentration of the powder is only 5 mg. This small value is due to the large relative surface area of ​​the small powder particles. A sample without added antimicrobial powder served as a control.

[0084] Figure 15 shows several samples of a commercially available facade paint to which increasing concentrations of the antibacterial hybrid material prepared on glass particles according to the present invention have been added. The powder concentrations are 0.1%, 0.5%, and 1.0% by weight. The antibacterial activity of the samples against Escherichia coli (E. coli) bacteria was determined after a zone of inhibition test. All samples showed significant antibacterial efficiency, which increased with increasing powder concentration. The antibacterial function of the hybrid material is not inhibited by the facade paint. Because film preservation of the facade paint does not require significant long-range effects, much lower concentrations of the hybrid material powder are sufficient for this application. A reference sample with high antibacterial activity was used as a control.

[0085] Figure 16 shows several samples of a commercially available antifouling paint to which increasing concentrations of hybrid antibacterial material powder prepared on cellulose powder were added. The powder concentrations were 2.0 wt%, 4.0 wt%, and 8.0 wt%. An antifouling coating without the antibacterial powder served as a control. The samples were stored in the North Sea for six weeks. After this time, the control sample already showed significant fouling, while the 2.0 wt% antibacterial powder showed fouling only in isolated areas. As the concentration of the antibacterial hybrid material powder increased, the low-level fouling further decreased.

[0086] Figure 17 shows a sample of Ultramid C33 containing 1 wt. % antibacterial microparticles prepared with commercially available silver powder. Figure 17a shows the granules, and Figure 17b shows the plate. Figure 17c shows the zone of inhibition test of the sample against Escherichia coli (E. coli). Both samples have moderate antibacterial activity. One sample on the plate was incubated in deionized water for 18 months, which was replaced periodically. The antibacterial activity of the sample does not change after incubation because its antibacterial activity is due to a catalytic process and not due to leaching of the biocide.

[0087] Figure 18 shows polyamide fibers containing 3 wt% catalytic antibacterial microparticles (Figure 18a). The microparticle powder used was produced by reducing silver ions in a chemical reduction process, followed by coating with ruthenium. In order for the powder to be incorporated into the fibers, the particle size must be less than 5 μm. The fibers have good antibacterial activity (Figure 18b).

[0088] Figure 19a shows an antibacterial hybrid material produced according to the present invention, whose core is made of ferromagnetic iron powder. Figure 19b shows how hybrid particles with ferromagnetic cores can be completely manipulated inside a glass container from the outside through the glass wall with a strong permanent magnet. Such hybrid systems can be used, for example, in biometric devices. Figure 19c shows the results of a hybrid antibacterial particle system (arrow) according to the present invention for PCR genomic analysis of Gram-positive B. subtilis bacteria. The antibacterial particle system according to the present invention was tasked with lysing B. subtilis (approximately 1 x 10 exp6 cells) in a 21 μl suspension containing PBS for 15 minutes at room temperature. Here, with the help of a magnet, the particles could be completely removed from the device after the experiment.

[0089] Figure 20 shows antibacterial hybrid material coated according to the present invention and uniformly dispersed in water by vigorous agitation. (a) Hybrid material particles are not post-coated, while (b) hybrid material particles are subsequently treated in a dopamine hydrochloride solution (2 mg / ml) and phosphate buffer (0.1 M, pH 8.5) at room temperature. The dopamine hydrochloride treatment converted the particle surface from its previous hydrophobic state to a hydrophilic state. This resulted in particles that were hydrophobic without the dopamine hydrochloride post-coating sinking to the bottom of the container immediately after agitation, but which can maintain a stable dispersion for a longer period due to the hydrophilized particles (Figure 20b).

[0090] Figure 21 shows the cellulose-based antibacterial hybrid material produced according to the present invention, whose antibacterial effect is not impaired by post-treatment. Figure 21a shows the antibacterial activity of cellulose-based hybrid particles produced according to the present invention without post-treatment against Escherichia coli (DSM498) suspension cultures (200 μl plated at 10 exp7 / ml) based on significant inhibition zones on agar. In Figure 21b, the same size Hemmhof shows that post-treatment of cellulose-based hybrid particles with ascorbic acid does not negatively alter the antibacterial activity of particles prepared according to the present invention. The same applies to post-treatment with chitosan (Figure 21c) and polydopamine (Figure 21d).

[0091] Figure 22 shows a cellulose-based antibacterial hybrid material incorporated into a sol-gel coating material (e.g., siloxane) to impart antibacterial activity to the sol-gel coating. Two siloxane coatings, H2084 and H5055 (Figure 22a), were used as the sol-gel coating. Hybrid cellulose-based particles were used as an antibacterial additive and added to the siloxane coating at a concentration of 5 wt%. After mixing, the dispersion was applied to the sample substrate by spraying. The coating was then crosslinked in a drying oven at an appropriate temperature. The powder particles showed good distribution on the sample surface. Figure 22b shows the results of an antibacterial test of Escherichia coli (E. coli) on agar on a polypropylene plate coated on one side with siloxane and 5 wt% of the cellulose-based hybrid antibacterial material of the present invention. An inhibition yard test using E. coli (DSM498) shows high antibacterial activity for the two samples. This also applies to samples subsequently incubated in a 1% solution of potassium sulfide for 5 minutes. The partially irregular inhibition halo is due to uneven spray application. It can be seen that the antimicrobial activity of the antimicrobial particles produced according to the present invention is largely unaffected by the siloxane coating. In this case, subsequent sulfide post-treatment also leads to increased antimicrobial efficacy of the dispersion coating system. Because the siloxane coating is hard and scratch-resistant in the polymerized state, this antimicrobial dispersion coating system is particularly suitable for surfaces subject to wear and tear.

[0092] Figure 23 shows the growth curves of MRSA bacteria using two ruthenium / ruthenium / silver / silver oxide powders at different powder concentrations. Ruthenium can be deposited on the silver surface, for example, by a direct, one-step chemical reduction route using different strong reducing agents (e.g., NaBH4, NH2H4), and ruthenium / ruthenium oxide can be deposited on the silver surface accordingly. However, ruthenium / ruthenium oxide can also be deposited in a two-step process in which ruthenium is first oxidized in the first step, and the oxidized ruthenium is reduced to ruthenium and ruthenium oxide only in the second step. Different process routes for ruthenium / ruthenium oxide deposition on silver particles were expected to result in comparable antibacterial effects. Surprisingly, however, the two-step process was found to have nearly one order of magnitude higher antibacterial activity against Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) with a silver / silver oxide / ruthenium / ruthenium oxide system compared to the direct one-step ruthenium deposition process. Unlike the direct one-step reduction of Ru(III) ions with a strong reducing agent, the indirect two-step process relies on the oxidation of Ru(III) ions to ruthenium(VIII) oxide [Chen 2011]. RuO4 is a strong oxidizing agent that is converted to ruthenium(IV) oxide by an appropriate reducing agent, coating the support material with a layer of ruthenium(IV) oxide. The oxidation of Ru(III) ions to RuO4 is carried out with sodium hypochlorite. To stabilize RuO4, the process is carried out in an alkaline medium. Reduction to RuO2 is carried out with sodium nitrite.

[0093] Ru / RuO onto silver particles using an indirect two-step process for ruthenium deposition x Preparation of semiconducting silver / silver oxide / ruthenium / ruthenium oxide powders by chemical reductive deposition of (AP383): 50 g of silver powder (Toyo Chemical Industrial, SBA10M27) was slurried in a 2000 ml three-neck flask containing 1000 ml of deionized water in an ultrasonic bath. The mixture was further stirred at 300 rpm using a KPG stirrer. After 2 hours, the brown suspension was decanted into another 2000 ml three-neck flask. While stirring in the ultrasonic bath and with a KPG stirrer, 10 ml of Ru(NO)(NO3)3 solution (10.83 g / L) was added. A mixture of the following solutions was then added to the suspension: 300 ml of NaClO solution (14%), 100 ml of NaOH solution (10 g / l), 87.5 ml of NaNO2 solution (10 g / l).

[0094] The silver powder quickly darkened. The suspension was then stirred in an ultrasonic bath for 1 hour. After the coating powder settled, the yellow supernatant was decanted. The powder was dissolved in deionized water and filtered. After washing with deionized water, the powder was dissolved in ethanol, filtered, and dried in a drying oven at 60°C.

[0095] Antibacterial effect Surprisingly, silver / silver oxide / ruthenium / ruthenium oxide powders in which ruthenium oxide was deposited by one-step and two-step chemical reduction processes, respectively, showed significantly different antibacterial activity against MRSA bacteria (Gram-positive). The silver / silver oxide / ruthenium / ruthenium oxide powder (AP823), deposited by direct ruthenium reduction onto silver particles using the strong reducing agent sodium borohydride (NaBH), exhibited antibacterial activity nearly one order of magnitude lower than the silver / silver oxide / ruthenium / ruthenium oxide powder (AP383) deposited by the two-step method. Figure 23 shows the growth curves of MRSA bacteria using two ruthenium / ruthenium oxide / silver / silver oxide powders with different amounts of powder. As can be seen from the shape of the growth curves, the two-stage silver / silver oxide / ruthenium / ruthenium oxide powder (AP383) showed complete kill of MRSA bacteria at 2.5 mg of weighed powder, whereas the one-stage silver / silver oxide / ruthenium / ruthenium oxide powder (AP823) showed complete kill only at 15 mg of powder. Thus, the two-stage ruthenium deposition method was found to have significantly increased antibacterial efficacy compared to the one-stage method, as indicated by the fact that complete disinfection required only 2.5 mg of powder for sample 383 (equivalent to the Ru deposition method as 392) and >10 mg for sample 823, or approximately one-sixth to one-quarter of the amount, over the entire 8-hour experimental period. In a study of the antibacterial activity of both types of powder (AP823) and (AP383) against P. aeruginosa PA14 (Gram-negative), a relatively large difference in antibacterial activity (approximately one order of magnitude) was found.

[0096] The antibacterial effect is particularly high for samples containing ruthenium(VI) oxide in the first half-cell (Table 2). Clearly, ruthenium(VI) oxide can be obtained by both electrochemical and PVD deposition of ruthenium, provided that a process step with a strong oxidizing effect on the ruthenium deposition (392 and RuOx) is present. XPS surface analysis shows a correlation between the antibacterial effect and the composition of the ruthenium oxide, likely depending on the specific ruthenium(VI) oxide / ruthenium(IV) oxide ratio. In either case, the presence of ruthenium(VI) oxide is beneficial or even necessary for enhanced antibacterial activity. [Table 2]

[0097] Literature binding energy (eV): ·Ru(0):Ru 3d:280,2 eV;JFMoulder,WFStickle,PESobol and KDBomben:Handbook of X Ray Photoelectron Spectroscopy:A reference of Standard Spectra for identification and interpretation of XPS Data,J.Chastain and JRCKing,Editors,p.115,Physical Electronics Eden Prairie,Minnesota(1995). ·RuO2:Ru 3d:280,66 eV;TPLuxton,MJEick,KGSchekel;Journal of Colloid and Interface Science 359,(2011)30-39. ·RuO3:Ru 3d:282,5 eV;TPLuxton,MJEick,KGSchekel;Journal of Colloid and Interface Science 359,(2011)30-39. RuO3:Ru 3d:282.4eV;R.Kotz,HJLewerenz and S.Stucki;J.Electrochem.Soc.130,No.4,1983,825-829.

[0098] In addition to the wet-chemical two-step Ru deposition onto silver, ruthenium and silver were also deposited by PVD coating onto PE foil, which has the advantage that no silver chloride is present on the PVD samples and any differences that may be detected can be more clearly attributed to the ruthenium half-cell. (A) PVD deposition: · (a) Ruthenium sputtering on silver (sample designation “Ru”). · (b) Reactive sputtering of silver and ruthenium (O2) (sample designation “RuOx”). (B) Chemical reductive ruthenium deposition: (c) Direct reduction for deposition of ruthenium on silver (sample designation "825"). (d) Reduction of ruthenium deposited on silver in the already described two-step process (oxidation + subsequent reduction, sample designation "392").

[0099] These four samples were analyzed by growth curve and surface composition (XPS analysis). In both studies, XPS analysis showed differences not only within each group (A) or (B) but also between groups (A) and (B), with an increase in antibacterial efficiency corresponding to the significant difference in surface composition.

[0100] Figure 24 shows the XPS spectra of samples Ru(a), RuOx(b), and 825(c), 392(d). Antibacterial testing, as described above, showed significant differences between the chemically reductively deposited and PVD-deposited Ru / RuOx / Ag / AgCl and AgOx half-cell combinations, respectively. XPS analysis reveals significant differences corresponding to different antibacterial effects. As can be seen in the Ru3d spectra (Figure 24), there are significant differences within and between the two groups in both the chemically reductively prepared sample groups 825(c) (curve (1)), 392(d) (curve (2)) and the PVD-coated sample groups Ru(a) (curve (3)), RuOx(b) (curve (4)). A narrow signal from metallic ruthenium (BE=280.1 eV) is seen in curve 1 of sample 825(a). The spectrum of sample Ru consists mostly of metallic ruthenium (65%), with about 24% assigned to RuO2. The RuOx(b) sample (curve (4) - PVD oxide sputtering) contains significantly less Ru(0), making the carbon component more prominent. The largest component (BE = 284.4 eV) can be attributed to metal carbides (C clearly comes from the PVD cleaning of the PE film). The ruthenium component of the spectrum is dominated by a signal at BE = 282.1 eV, which accounts for approximately 85% and can be assigned to RuO3**. The half-width of this component is so large that the contribution of other compounds to the signal cannot be excluded. The remaining Ru component in the spectrum is caused by Ru(VI) or oxidized hydrates of higher oxidation states of ruthenium. Curve (2) of sample 392(d) is similar to curve 4 of sample RuOx(b), and also contains significant concentrations of RuO3**. However, there are also other compounds that may be oxide hydrates. However, Ru compounds with higher valences are also possible. The Ru(0) and RuO2 contents are low. **) According to literature data (Table 1), RuO3 is located at 282.2 eV - 282.6 eV.

[0101] The oxygen O1s spectrum (Figure 25) shows the same grouping of samples as described for the Ru3d spectrum. The Ru and 825 samples give virtually identical spectral shapes, which can be matched to three components. The metal oxide is expected to have a BE of 530 eV. The components with higher BEs may represent hydroxides and hydrates. However, a significant portion of these are likely due to the adsorbent. The RuOx sample is likely heavily influenced by the adsorbent. Additionally, O atoms are found in ruthenium oxide. Sample 392 shows only a small proportion of oxidized oxygen atoms. The majority are bound in hydrates. Meanwhile, hydroxides are likely yet to be found.

[0102] XPS analysis shows some differences in the oxide composition of the tested samples. The significant, and perhaps main, reason for the increased antibacterial effect may be the presence of the hexavalent oxidation state of ruthenium, in addition to RuO2 and metallic Ru(0), in the samples with high antibacterial effect. In particular, in the PVD samples without AgCl, this side may not have any effect on the increased antibacterial effect.

Claims

1. 1. A hybrid material provided as an additive for materials, substances and / or coating materials for producing an antibacterial, antiviral and / or fungicidal effect, the hybrid material comprising particles, each of which comprises at least one support material at least partially coated with at least two different metal compounds, at least one first metal compound and one second metal compound being in conductive contact with each other at least on their respective surfaces, the first metal compound comprising at least one semiconductor compound of ruthenium exhibiting multiple oxidation states and allowing for change of said oxidation state by catalytically active centers, and the second metal compound comprising at least one conductive silver semiconductor, both metal compounds establishing a short-circuited half-cell in the presence of water and oxygen, resulting in the antibacterial, antiviral and / or fungicidal effect, the support material comprising at least one material selected from the group consisting of cellulose, zeolite, silicate, metal alloy, metal oxide and graphite.

2. The hybrid material of claim 1 , characterized in that the carrier material comprises cellulose.

3. 3. The hybrid material according to claim 1 or 2, characterized in that it is modified with an organic polymer and / or ascorbic acid or a derivative of ascorbic acid.

4. 2. The hybrid material of claim 1, characterized in that the intensity of the antibacterial effect is adjustable by adjusting the amount of at least one of both metal compounds and / or the ratio of both metal compounds on the surface of the particle.

5. 2. The hybrid material of claim 1, wherein the ruthenium compound comprises ruthenium present in one or both of oxidation states VI and IV.

6. 6. The hybrid material according to claim 1, wherein the ruthenium compound comprises at least one of ruthenium oxide, ruthenium oxyhydrate, ruthenium hydroxide, ruthenium oxyhydroxide, ruthenium halide and / or at least one ruthenium sulfide.

7. 2. The hybrid material of claim 1, wherein the silver semiconductor comprises at least one of silver oxide, silver hydroxide, silver halide, or silver sulfide, or a combination of metallic silver with silver oxide, silver hydroxide, silver halide, or silver sulfide.

8. 2. The hybrid material according to claim 1, characterized in that the particles have a spherical or polyhedral shape and an average diameter of up to 100 μm and / or the particles have a fibrous shape and an average length of up to 1 mm.

9. The following process: a) providing or producing a particulate support material, said support material comprising at least one material selected from the group consisting of cellulose, zeolite, silicate, metal alloy, metal oxide, and graphite; b) at least partially applying a first metal compound onto the support material, the first metal compound comprising at least one semiconducting compound of ruthenium exhibiting multiple oxidation states and allowing the change of said oxidation state by catalytically active centers; c) at least partially applying a second metal compound onto the support material and / or the first metal compound, the second metal compound comprising at least one conductive silver semiconductor, and both metal compounds being applied in conductive contact with each other at least on their respective surfaces; A method for producing the hybrid material according to any one of claims 1 to 8, comprising:

10. 10. The method according to claim 9, characterized in that at least one of both metal compounds is applied onto the support material and / or other metal compound in the form of clusters, nanoporosity, microcracks and / or single particles.

11. 11. The method according to claim 9 or 10, characterized in that after step a) and / or step c), the support material and / or the metal compound are modified with an organic polymer and / or with ascorbic acid or a derivative of ascorbic acid.

12. A method according to claim 9, 10 or 11, characterized in that a link layer is produced on at least one metal compound, said link layer comprising at least one metal compound selected from the group consisting of halides, oxides and sulfides of the corresponding metal compound.

13. 13. The method according to any one of claims 9 to 12, characterized in that the intensity of the antibacterial effect is adjusted by adjusting the amount of at least one of both metal compounds and / or the ratio of both metal compounds on the surface of the particle.

14. 14. The method according to any one of claims 9 to 13, characterized in that the respective metal compounds are applied sequentially or simultaneously by electrochemical deposition, chemical reduction deposition, electrophoretic coating, baking, PVD, CVD and / or sol-gel processes.

15. 15. The method according to any of claims 9 to 14, characterized in that the application of the second metal compound to the support material and / or the first metal compound comprises at least one step having a strong oxidizing effect.

16. 16. A method according to any one of claims 9 to 15, characterized in that after applying both metal compounds a thermal post-treatment is carried out to adjust the specific oxidation state.

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