Antibacterial and antiviral metal oxides and methods for producing and using same

Abstract

To provide a metal oxide having high antibacterial and antiviral properties in the dark.SOLUTION: There is provided an antibacterial and antiviral metal oxide represented by the following formula (1). (La1-x1-x2-x3Cex1 Prx2Max3)2(Mo1-y1-y2 Vy1Mby2)2O9...(1). In the above formula (1), Ma is any one or more types selected from the group consisting of Nd, Eu, Gd and Tb. Mb is any one or more types selected from the group consisting of W, Cr and Nb. The relation of the following formulas is satisfied: 0≤x1≤0.3, 0≤x2≤0.3, 0≤x3≤0.1, 0≤x1+x2+x3≤0.5, 0.1≤y1≤0.5, 0≤y2≤0.1 and 0.1≤y1+y2≤0.5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to antimicrobial, antiviral metal oxides and methods of making and using same. [Background technology]

[0002] In the past, humanity has been threatened by bacterial or viral pandemics. Once a pandemic occurs, it has a variety of adverse effects, including on the economy, in addition to direct health damage. Therefore, it is important to prevent pandemics as much as possible. One of the means of preventing pandemics in advance is antibacterial and antiviral materials that inhibit the growth of bacteria and viruses.

[0003] Antibacterial and antiviral materials are broadly classified as organic or inorganic, but inorganic materials are mainly used due to the limitations of the usage environment and the durability of antibacterial and antiviral properties. Inorganic antibacterial and antiviral materials that have been put to practical use include photocatalyst systems such as TiO2 as disclosed in Patent Document 1, and metal systems using Ag nanoparticles, Cu nanoparticles, etc. as disclosed in Patent Document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-93767 A [Patent Document 2] JP 2009-46410 A Summary of the Invention [Problem to be solved by the invention]

[0005] The photocatalytic antibacterial and antiviral material disclosed in Patent Document 1 is based on a photocatalyst, and therefore requires visible light to exhibit antibacterial and antiviral properties, and does not exhibit antibacterial and antiviral properties in the dark.

[0006] The metal-based antibacterial and antiviral material disclosed in Patent Document 2 has high antibacterial activity with a viable bacteria reduction rate of 99% in a few hours even in the dark. However, the antiviral activity is weak with an infectivity reduction rate that does not reach 99% even after several tens of hours. Another problem is that the cost is very high.

[0007] The present invention has been made in view of the above circumstances, and one of its objects is to provide a metal oxide having high antibacterial and antiviral properties in a dark place, and a method for producing and using the same. [Means for solving the problem]

[0008] Aspect 1 of the present invention is It is an antibacterial and antiviral metal oxide represented by the following formula (1). (La 1-x1-x2-x3 Ce x1 Pr x2 Ma x3 )2(Mo 1-y1-y2 V y1 Mb y2 )2O9···(1) In the above formula (1), Ma is one or more selected from the group consisting of Nd, Eu, Gd, and Tb, and Mb is one or more selected from the group consisting of W, Cr, and Nb, and the relationships 0≦x1≦0.3, 0≦x2≦0.3, 0≦x3≦0.1, 0≦x1+x2+x3≦0.5, 0.1≦y1≦0.5, 0≦y2≦0.1, and 0.1≦y1+y2≦0.5 are satisfied.

[0009] Aspect 2 of the present invention is A step of mixing and stirring lanthanum oxide, molybdenum oxide, vanadium oxide, and optionally cerium oxide and / or praseodymium oxide in a dispersion medium; removing the dispersion medium to obtain a mixed powder; and heating the mixed powder to 900 to 1100°C.

[0010] Aspect 3 of the present invention is A method for reducing the viable count of bacteria on a substrate and / or reducing the infectivity titer of viruses on the substrate, comprising applying the antibacterial and antiviral metal oxide according to embodiment 1 to the substrate.

[0011] A fourth aspect of the present invention is An antibacterial and antiviral composition comprising the antibacterial and antiviral metal oxide according to embodiment 1 and a dispersion medium.

[0012] A fifth aspect of the present invention is An antibacterial and antiviral product comprising the antibacterial and antiviral metal oxide according to embodiment 1 on its surface. Effect of the Invention

[0013] According to an embodiment of the present invention, a metal oxide having high antibacterial and antiviral properties in a dark place can be provided. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a flow chart illustrating a solid-phase diffusion method, which is an example of a method for producing an antibacterial and antiviral metal oxide according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows the results of X-ray diffraction measurement of (La0.7Ce0.3)2(Mo0.6V0.4)2O9, which is an antibacterial and antiviral metal oxide according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a flowchart showing an antibacterial and antiviral activity evaluation method according to an embodiment of the present invention. [Figure 4] FIG. 4 is a table summarizing the antibacterial and antiviral evaluation results of the examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present inventors have investigated from various angles in order to realize a metal oxide having high antibacterial and antiviral properties in the dark, and as a result, have focused on La2Mo2O9. Although La2Mo2O9 is known as an ionic conductor, it has not been investigated as an antibacterial and antiviral material. It has been found that by substituting molybdenum (Mo) in this La2Mo2O9 with vanadium (V) at a predetermined ratio, it exhibits high antibacterial and antiviral properties in the dark. This is thought to be due to the fact that vanadium, as an acidic oxide, can realize surface acidification and lower the pH, which results in increased antibacterial properties and removal of the outermost envelope of the virus particle and the virus particle itself. The present inventors have also found that in the above case, high antibacterial and antiviral properties are exhibited even when lanthanum (La) is substituted with cerium (Ce) and / or praseodymium (Pr) (also called praseodymium) at a predetermined ratio.

[0016] Hereinafter, the antibacterial and antiviral metal oxides and their manufacturing and use methods according to the present disclosure will be described with reference to the drawings as necessary. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of already well-known matters or duplicate explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the explanations and to facilitate understanding by those skilled in the art.

[0017] The antibacterial and antiviral metal oxide according to an embodiment of the present invention is represented by the following formula (1). (La 1-x1-x2-x3 Ce x1 Pr x2 Ma x3 )2(Mo 1-y1-y2 V y1 Mb y2 )2O9···(1) In the above formula (1), Ma is one or more selected from the group consisting of Nd, Eu, Gd, and Tb, and Mb is one or more selected from the group consisting of W, Cr, and Nb, and the relationships 0≦x1≦0.3, 0≦x2≦0.3, 0≦x3≦0.1, 0≦x1+x2+x3≦0.5, 0.1≦y1≦0.5, 0≦y2≦0.1, and 0.1≦y1+y2≦0.5 are satisfied.

[0018] La may be substituted with Ce and Pr. However, if a certain amount of La is substituted with Ce and Pr in excess (specifically, if either the relationship x1>0.3 or x2>0.3 is satisfied), the crystal structure of A2B2O9 (A is a rare earth element, B is a transition metal element) cannot be maintained, and there is a risk of a mixed phase. If a mixed phase occurs, there is a risk that the antibacterial and antiviral properties cannot be increased. Also, if the amount is small, it is permissible to replace La with elements other than Ce and Pr (also called "Ma" and one or more selected from neodymium (Nd) (also called neodymium), europium (Eu), gadolinium (Gd) and terbium (Tb). However, if La is replaced by Ma in an excess amount (specifically, if the total content of Ma (x3) exceeds 0.1), the crystal structure of A2B2O9 cannot be maintained and there is a risk of a mixed phase. Furthermore, even if a certain amount of La is super-substituted regardless of the element type (specifically, if the relationship (x1+x2+x3)>0.5 is satisfied), the crystal structure of A2B2O9 cannot be maintained, and a mixed phase may occur. Whether or not the crystal structure is A2B2O9 can be checked by X-ray diffraction. Specifically, when X-ray diffraction is measured on the target metal oxide, and 19 or more peaks of La2Mo2L9 indicated by black circles are detected as shown in FIG. 2 described later, the metal oxide can be judged to have the crystal structure (and composition) of A2B2O9 (note that a slight shift in the peak position caused by replacing La and Mo with other elements is allowed). Whether or not x1, x2, x3, y1, and y2 in the above formula (1) are within a predetermined range can be checked by, for example, a general composition analysis (EDX, etc.). Note that impurities other than the elements specified in the above formula (1) may also be detected in the composition analysis, and those in which a small amount (for example, 3 atomic % or less) of La or Mo is replaced by these impurities are also included in the embodiments of the present invention.

[0019] When a certain amount of Mo is substituted with V (specifically, when the relationship y1>0.5 is satisfied), the crystal structure of A2B2O9 cannot be maintained and a mixed phase occurs. On the other hand, when the amount of Mo substituted with V is less than a certain amount (specifically, when the relationship y1<0.1 is satisfied), the surface acidification does not proceed well, and the antibacterial and antiviral properties cannot be improved. y1 is preferably 0.2 or more, more preferably 0.3 or more, and even more preferably 0.4 or more. This allows the antibacterial and antiviral properties to be further improved. In addition, Mo may be replaced with trace amounts of elements other than V (referred to as "Mb" and selected from one or more of tungsten (W), chromium (Cr) and niobium (Nb). However, if Mo is replaced with Mb in an amount exceeding a certain amount (specifically, if the total Mb content (y2) exceeds 0.1), coloring may occur due to the replacement, which may narrow industrial applications, and the antibacterial and antiviral properties may decrease due to the surface not being acidified properly. Furthermore, even if a certain amount of Mo is super-substituted regardless of the element type (specifically, if the relationship (y1+y2)>0.5 is satisfied), the crystal structure of A2B2O9 cannot be maintained, and there is a risk of a mixed phase occurring.

[0020] In the antibacterial and antiviral metal oxide according to the embodiment of the present invention, when La is replaced with Ce, the antibacterial and antiviral properties can be further enhanced, which is preferable. Specifically, x1 is preferably greater than 0, and more preferably 0.1 or more. This is believed to be due to the fact that Ce is more likely to form a compound with phosphoric acid, which is a nutrient for bacteria, thereby realizing phosphoric acid removal and antibacterial properties, etc.

[0021] A method for producing an antibacterial and antiviral metal oxide according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a flow chart showing a solid-phase diffusion method, which is an example of a method for producing an antibacterial and antiviral metal oxide according to an embodiment of the present invention. The solid-phase diffusion method includes (1) a step of mixing and stirring a rare earth oxide and a metal oxide in a dispersion medium, (2) a step of removing the dispersion medium to obtain a mixed powder, and (3) a step of heating the mixed powder to 900 to 1100°C. It is preferable to include a primary crushing step before the heating step (3), and a secondary crushing step after the heating step (3). Each step will be described in detail below.

[0022] <(1) Mixing and stirring process> The rare earth oxide and the metal oxide are mixed and stirred in a dispersion medium. This allows the rare earth oxide and the metal oxide to be thoroughly (uniformly) mixed. The rare earth oxide contains at least lanthanum oxide (La2O3, LaO, etc.). The rare earth oxide may further contain cerium oxide (CeO2, Ce2O3, etc.) and / or praseodymium oxide (Pr6O 11 The metal oxide may include molybdenum oxide (MoO3, MoO2, etc.) and vanadium oxide (VO2, V2O3, V2O5, etc.). Trace amounts of oxides of Ma and Mb may be included. It is preferable to mix these oxides so as to satisfy the predetermined ratio of the above formula (1).

[0023] The dispersion medium is not particularly limited as long as it can disperse the rare earth oxide and metal oxide, but an organic solvent having a boiling point of less than 100° C. is preferable, and examples of the dispersion medium include lower alcohols such as methanol, ethanol, and 2-propanol, and ketones such as acetone. The dispersion medium may be used alone or in combination of two or more kinds.

[0024] <(2) Dispersion medium removal process> After the mixing and stirring step (1), the dispersion medium is removed. The removal method is not particularly limited, but may be, for example, heating to a temperature equal to or higher than the boiling point of the dispersion medium using a dryer to volatilize it. By removing the dispersion medium, a mixed powder of the rare earth oxide and the metal oxide is obtained.

[0025] <(3) Heating process> After the dispersion medium removal step (2), the mixed powder is heated to 900 to 1100°C. If the temperature is less than 900°C, the solid-phase reaction may not proceed well, and the desired crystal structure of A2B2O9 may not be obtained. On the other hand, if the temperature is more than 1100°C, the solid-phase reaction may proceed excessively, and other different phases may be generated, and there is also a problem that the powders may strongly adhere to each other and become difficult to handle. The heating rate can be, for example, 5°C / min or more, and the heating time can be, for example, 12 hours or more. The heating step may be a two-stage heating step, and may include a pre-heating step (also called "first heating") of heating to 500 to 700°C before heating to 900 to 1100°C (also called "main heating" or "second heating"). By including the pre-heating step, even a large amount of mixed powder can be heated uniformly. From the above, an antibacterial and antiviral metal oxide according to an embodiment of the present invention can be obtained. After the heating is completed, the temperature can be lowered to room temperature at a rate of 5° C. / min or more.

[0026] The method for producing an antibacterial and antiviral metal oxide according to the embodiment of the present invention may include a step of crushing the mixed powder obtained after the (2) dispersion medium removing step (sometimes referred to as a primary crushing step), if necessary. This allows the agglomerates of the mixed powder to be broken down into smaller particles, which increases the contact efficiency between the rare earth oxide and the metal oxide, allowing the antibacterial and antiviral metal oxide to be obtained by heating for a shorter period of time. The crushing method is not particularly limited, and may be, for example, crushed in a mortar for 5 minutes or more.

[0027] The method for producing an antibacterial and antiviral metal oxide according to an embodiment of the present invention may further include a crushing step (sometimes referred to as a secondary crushing step) after the heating step ((3)), as necessary. This makes it possible to loosen powder particles that have adhered to each other due to solid-phase diffusion, which is effective, for example, when the product is used by application. The crushing method is not particularly limited, and may be, for example, crushed in a mortar for 5 minutes or more.

[0028] The particle size of the antibacterial and antiviral metal oxide according to the embodiment of the present invention is not particularly limited, but for example, an average particle size (equivalent circle diameter, median diameter) of 3 to 10 μm is preferable since antibacterial and antiviral properties are easily exhibited. The antibacterial and antiviral metal oxide according to the embodiment of the present invention can be used as a composition (liquid) (containing the antibacterial and antiviral metal oxide and a dispersion medium) by dispersing it in, for example, the above-mentioned dispersion medium. By applying (for example, coating) the composition to a target product, antibacterial and antiviral properties can be imparted to the target product. The antibacterial and antiviral metal oxide according to the embodiment of the present invention can impart antibacterial and antiviral properties to a target product, for example, by being contained on the surface of the product. For example, by containing the antibacterial and antiviral metal oxide according to the embodiment of the present invention in a resin product, a metal product, a ceramic product, or the like, or coating the surface of such products, a product containing the antibacterial and antiviral metal oxide according to the embodiment of the present invention on its surface can be provided. As an example of a method of using the antibacterial and antiviral metal oxide according to an embodiment of the present invention, the antibacterial and antiviral metal oxide according to an embodiment of the present invention can be applied to a substrate (including, but not limited to, glass, etc.) to reduce the viable cell count of bacteria (including, but not limited to, Escherichia coli, Staphylococcus aureus, etc.) on the substrate, and / or reduce the infectivity titer of viruses (including, but not limited to, bacteriophage Qβ, influenza virus, coronavirus, norovirus, etc.). EXAMPLES

[0029] The following examples are provided to more specifically describe the embodiments of the present invention. The embodiments of the present invention are not limited to the following examples, and may be modified as appropriate within the scope of the above and below-described aims, and all of these are included in the technical scope of the embodiments of the present invention.

[0030] La2O3, MoO3, VO2, and optionally CeO2 and / or Pr6O 11 and were mixed in a predetermined ratio. The mixed powder was put into a beaker together with ethanol, and mixed and stirred at 400 rpm for 1 hour using a stirrer and a rotor. In order to remove the ethanol, the mixture was dried at 120°C for 2 hours using a dryer to obtain a mixed powder. The mixed powder was crushed for 15 minutes using a mortar so as to break up the aggregates. The crushed mixed powder was placed in an alumina crucible, covered, and put into a muffle furnace. The heating and cooling rates were set to 5°C / min, and the mixture was heated at 500°C for 12 hours and then at 900°C for 12 hours. The heated powder was crushed for 15 minutes using a mortar to obtain antibacterial and antiviral metal oxides (average particle size: 3 to 10 μm) of Examples 1 to 10.

[0031] In order to confirm that the antibacterial and antiviral metal oxide obtained above has a crystal structure of A2B2O9, a crystal structure measurement was carried out by X-ray diffraction. The crystal structure measurement was carried out using a D2PHASER (manufactured by Bruker). As an example of this embodiment, the (La 0.7 Ce 0.3)2(Mo 0.6 V 0.4 The measurement results for )2O9 are shown in Figure 2. In Figure 2, the solid line indicates (La 0.7 Ce 0.3 )2(Mo 0.6 V 0.4 )2O9, the circles represent the peak positions of the crystal structure data of La2Mo2O9 stored in the ICDD powder diffraction and crystal structure database. The peak positions in the figure and the positions of the circles were almost identical. Thus, it was found that the antibacterial and antiviral metal oxide obtained above has a crystal structure of A2B2O9.

[0032] The antibacterial and antiviral properties of the antibacterial and antiviral metal oxide obtained above were evaluated. The method for evaluating the antibacterial and antiviral properties will be described with reference to Fig. 3. Fig. 3 is a flow chart for explaining the method for evaluating the antibacterial and antiviral properties. (1) Preparation of evaluation specimens Ethanol was added so that the antibacterial and antiviral metal oxide was 1 mg / mL, and a dispersion liquid of the antibacterial and antiviral metal oxide was prepared. 150 μL of the dispersion liquid was dropped onto the center of a slide glass arranged in a darkened work area, and the slide glass was dried in a dark room. The operation of dropping onto the slide glass was repeated twice to prepare an evaluation test piece. (2) Preparation of test bacteria and virus solutions In carrying out the antibacterial and antiviral evaluation, the bacterial species was Escherichia coli and the viral species was bacteriophage Qβ. The test bacterial solution was obtained by pre-culturing Escherichia coli in NA and suspending it in 1 / 500 nutrient bouillon (NB, Eiken Scientific Co., Ltd.) to prepare a bacterial suspension of approximately 107 cfu / mL. The test virus solution was prepared by mixing bacteriophage Qβ with the host bacterium (Escherichia coli), culturing it at 35°C for 15 hours, stomaching it at 260 rpm for 2 minutes, leaving it to stand at 35°C for 1 hour, centrifuging it at 3500 rpm for 20 minutes, filtering it through a 0.22 μm pore membrane filter, and suspending it in 1 / 500 nutrient bouillon (NB, Eiken Scientific Co., Ltd.) to prepare a virus solution of approximately 107 cfu / mL. (3) Antibacterial and antiviral tests After drying the above-mentioned evaluation test pieces that had been sterilized by high-pressure steam, 0.02 mL of the above-mentioned test bacterial liquid and test virus liquid were dropped onto them and covered with a film.Then, they were placed in a Tupperware and left to stand in a dark room at 35°C and a relative humidity of 90% or more for a specified period of time, and the evaluation test pieces were taken out. (4) Measurement of viable cell count and bacteriophage infectivity After the predetermined time had elapsed, the viable cell count or bacteriophage infectivity titer was measured for each evaluation test piece. To measure the viable bacterial count, the evaluation test specimen was placed in a stomacher bag, the test specimen was washed with 10 mL of SCDLP medium (manufactured by Nissui Pharmaceutical), and the test specimen was gradually diluted with 0.85% saline. After culturing at 35°C for 2 days using the SA pour culture method, the viable bacterial count per test specimen was measured. In addition, the bacteriophage infectivity titer measurement test specimens were placed in a stomacher bag, thoroughly washed by hand, and then serially diluted with 0.85% saline. The specimens were mixed with the host bacterial liquid and then cultured at 37°C for 16 to 20 hours, after which the bacteriophage infectivity titer per test specimen was measured. The reduction rate was calculated as (CD) / C, where C is the number of viable bacteria and the bacteriophage infectivity per evaluation specimen at the initial state of 0 h, and D is the number of viable bacteria and the bacteriophage infectivity per evaluation specimen after 6 hours.

[0033] The antibacterial and antiviral evaluation was carried out using the metal oxides of Comparative Examples 1 to 5 and the anatase type TiO2 (manufactured by Kojundo Chemical Laboratory) of Comparative Example 6, as well as the antibacterial and antiviral metal oxides of Examples 1 to 10. The results are shown in Figure 4.

[0034] From the results of FIG. 4, the following can be considered. All of the antibacterial and antiviral metal oxides of Examples 1 to 10 in FIG. 4 satisfied the requirements defined in the embodiment of the present invention, and had high antibacterial and antiviral properties in the dark (i.e., the reduction rate after 6 hours in both antibacterial and antiviral evaluations was 99% or more). Particularly in Examples 1 to 3, in the range of y1=0.1 to 0.5 in the above formula (1), the higher the V content (larger y1), the higher the antibacterial and antiviral properties tended to be. Also, as in Examples 4 and 5, as long as 0≦x1≦0.3 was satisfied in the above formula (1), the replacement of La with Ce tended to result in higher antibacterial and antiviral properties. On the other hand, none of the metal oxides of Comparative Examples 1 to 6 satisfied the requirements defined in the embodiment of the present invention, and did not exhibit high antibacterial and antiviral properties in the dark.

[0035] The metal oxide of Comparative Example 1 did not contain V (that is, y1<0.1 in the above formula (1)), and both the antibacterial property and the antiviral property were less than 99%.

[0036] The metal oxide of Comparative Example 2 contained an excess of V (i.e., y1>0.5 in the above formula (1)), and both the antibacterial and antiviral properties were less than 99%. This is thought to be because the A2B2O9 crystal structure could not be maintained due to the excessive addition of V, resulting in the generation of a mixed phase.

[0037] The metal oxide of Comparative Example 3 contained an excess of Ce (i.e., x1>0.3 in the above formula (1)), and both the antibacterial and antiviral properties were less than 99%. This is thought to be due to the fact that the A2B2O9 crystal structure could not be maintained due to the excessive addition of Ce, resulting in the generation of mixed phases, and the reduction in the phosphoric acid removal effect.

[0038] The metal oxide of Comparative Example 4 contained an excess of Pr (i.e., x2>0.3 in the above formula (1)), and both the antibacterial and antiviral properties were less than 99%. This is thought to be due to the fact that the A2B2O9 crystal structure could not be maintained due to the addition of an excess of Pr, resulting in the generation of a mixed phase, and the reduction in the phosphoric acid removal effect.

[0039] The metal oxide of Comparative Example 5 had an excessive total content of Ce and Pr (i.e., (x1+x2+x3)>0.5 in the above formula (1)), and both the antibacterial and antiviral properties were less than 99%. This is thought to be due to the fact that the A2B2O9 crystal structure could not be maintained due to the excessive total content of Ce and Pr, resulting in the generation of a mixed phase, and a decrease in the phosphate removal effect.

[0040] The TiO2 of Comparative Example 6 had both antibacterial and antiviral properties of less than 99%. It is clear that TiO2, which is a photocatalyst, has insufficient antibacterial and antiviral properties in a dark place. [Industrial Applicability]

[0041] The antibacterial and antiviral metal oxide according to the embodiment of the present invention has high antibacterial and antiviral properties, and therefore can be used as an antibacterial and antiviral material. In addition, for example, by incorporating it into a resin or coating it on a surface, it can also impart antibacterial and antiviral properties to various products.

Claims

1. An antibacterial and antiviral metal oxide represented by the following formula (1): (LL １－ｘ１－ｘ２－ｘ３ Ce ｘ１ Pr ｘ２ Ma ｘ３ ) ２ (Mo １－ｙ１－ｙ２ V ｙ１ Mb ｙ２ ) ２ O ９ ・・・(1) In the above formula (1), Ma is one or more selected from the group consisting of Nd, Eu, Gd, and Tb, and Mb is one or more selected from the group consisting of W, Cr, and Nb, and the relationships of 0≦x1≦0.3, 0≦x2≦0.3, 0≦x3≦0.1, 0≦x1+x2+x3≦0.5, 0.1≦y1≦0.5, 0≦y2≦0.1, and 0.1≦y1+y2≦0.5 are satisfied.

2. A method for reducing the viable count of bacteria on a substrate and / or reducing the infectivity titer of viruses on the substrate, comprising applying the antibacterial and antiviral metal oxide according to claim 1 to the substrate.

3. An antibacterial and antiviral composition comprising the antibacterial and antiviral metal oxide according to claim 1 and a dispersion medium.

4. An antibacterial and antiviral product comprising the antibacterial and antiviral metal oxide of claim 1 on its surface.

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