Antibacterial Surfaces with Conductive Particles

Abstract

The antimicrobial article includes a support layer and an antimicrobial layer. The antimicrobial layer has a first major surface formed at least in part by a plurality of particles and a second major surface bonded to the support layer. Each particle of the plurality of particles is formed by a bead of a non-conductive material. The first set of particles includes beads coated with a first conductive material.

Description

[Technical field]

[0001] The present technology relates generally to antimicrobial surfaces, and in particular to antimicrobial scratch resistant surfaces. Summary of the Invention

[0002] In one aspect, the present application relates to an antimicrobial article including a support layer and an antimicrobial layer. The antimicrobial layer has a first major surface formed at least in part by a plurality of particles and a second major surface bonded to the support layer. Each particle of the plurality of particles includes a bead of a non-conductive material. A first set of the particles includes beads coated with a first conductive material.

[0003] In another aspect, the disclosure relates to a method of using an article, the method comprising applying a liquid to a first major surface of the article, the liquid optionally being an electrolyte. [Brief description of the drawings]

[0004] [Figure 1] FIG. 2 is a cross-sectional view of an antimicrobial article. [Diagram 2] 2 is a cross-sectional view of the antimicrobial article of FIG. 1 after some use. [Diagram 3] FIG. 2 is a plan view of an antimicrobial layer that may be used in the antimicrobial article of FIG. 1 having conductive particles and uncoated particles. [Figure 4] 4 is a plan view of an alternative antimicrobial layer that may be used in the antimicrobial article of FIG. 1 having a higher ratio of conductive particles relative to uncoated particles than the antimicrobial layer of FIG. 3. [Diagram 5] 2 is a cross-sectional view of an antimicrobial layer that can be used in the antimicrobial article of FIG. 1 having multiple barrier regions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] As seen in Figures 1 and 2, the antimicrobial article 10 may be applied to or used on the surface of a substrate 16 to provide antimicrobial properties, particularly antimicrobial and antiviral properties, to the substrate surface. Generally, the antimicrobial article 10 includes a support layer 14 and an antimicrobial layer 12 bonded to the support layer. The antimicrobial properties may be provided by various mechanisms, such as metal ion release or galvanic microcurrents. The article 10 may also provide a scratch-resistant surface, which may promote sustained antimicrobial performance over a longer period of time, as compared to a substrate surface, such as a polymeric film, that does not have the antimicrobial article. The antimicrobial article 10 may be particularly useful, for example, as a durable antimicrobial cover for high-touch surfaces.

[0006] With respect to antimicrobial performance, the antimicrobial article 10 can provide a first major surface 18 capable of providing antimicrobial, antiviral, or both types of performance at various minimum thresholds. Antimicrobial performance can be promoted by the presence of moisture. Moisture can be provided by the surrounding environment, such as moisture in the air. Moisture can also be added, such as by wiping with a cloth dampened with water or an electrolyte solution.

[0007] Antimicrobial performance can be measured as log reduction value (LRV), which is calculated according to Equation 1: Equation 1:

number

[0008] A "coated sample" refers to an antimicrobial article 10 having at least an antimicrobial layer 12 on a support layer 14. A "control sample" refers to a similar article without the antimicrobial layer 12, such as an article similar to article 10 including beads 24 except without the coating of conductive material 22. The organisms may be microorganisms such as bacteria or viruses. A higher LRV indicates a greater reduction in organisms compared to the coated sample and the control sample. The LRV may be determined using measurements from the ISO 22196:2011 "Measurement of Antibacterial Activity on Plastic and Other Non-Porous Surfaces" method, which includes bacterial kill tests and viral kill tests described in more detail elsewhere herein.

[0009] The antimicrobial article 10 can provide an organism LRV of 2, 3, 4, 4.5, or even 5 or more one hour after application to the first major surface 18. In some embodiments, the article 10 can provide a bacterial LRV of 2, 3, 4, 4.5, or even 5 or more one hour after application to the first major surface 18. The article can further provide a bacterial LRV of greater than 5, for example, after 6 hours. In some embodiments, the article 10 can provide a viral LRV of 2, 3, 3.5, 4, or even 4.5 or more ten minutes after application to the first major surface 18.

[0010] As used herein, the term "major surface" refers to the largest surface or one of the largest surfaces of an object. For example, a film or paper article may have a first major surface, a second major surface, and a side (or edge) connecting the major surfaces.

[0011] A variety of substrates 16 can be used in the antimicrobial article 10, which may be coupled to the support layer 14. In some embodiments, the substrate 16 may be a three-dimensional object, such as a table, countertop, door handle, steering wheel, chair armrest, appliance, electronic device, or other touchable or high-touch surface. In some embodiments, the substrate 16 may be a substantially planar article, such as a polymeric film, a polymeric adhesive layer, fabric, paper, glass, wall material, or metal. Such substantially planar articles may be applied to three-dimensional objects. For example, the antimicrobial article 10 may be applied to a decorative film, which may then be applied to a tabletop. Although the substrate 16 is described as a separate component, it may also be considered part of the antimicrobial article 10.

[0012] The antimicrobial layer 12 includes a plurality of particles 26. The support layer 14 is configured to physically bond the particles 26 of the antimicrobial layer 12 in a substantially fixed position relative to one another along the article 10. As used herein, the term "bond" means to attach, join, adhere, or otherwise physically join one component to another component.

[0013] Any suitable material capable of physically binding or bonding a plurality of particles 26 can be used to form the support layer 14. The support layer 14 may also be described as a binder or binder layer. In some embodiments, the support layer 14 is or includes a polymer adhesive or film. Non-limiting examples of materials that may be used for the support layer 14 include polyolefin, polyester, polyurethane, vinyl, polyester, polyethylene, acrylic adhesive, epoxy, rubber, or silicone.

[0014] In one example, the antimicrobial article 10 includes an antimicrobial layer 12, a support layer 14 including a polyester as a binder, and a substrate 16 including a fabric, which can provide a flexible antimicrobial surface for a garment. In another example, the antimicrobial article 10 includes an antimicrobial layer 12 and a support layer 14 including a polymer adhesive, which may be applied to or may further include a substrate 16 including a table.

[0015] The support layer 14 may have any suitable total thickness. The thickness may be 10, 25, 50, 100, 250, or even 500 micrometers or more. The thickness may be 1000, 500, 250, 100, 50, or even 25 micrometers or less.

[0016] The antimicrobial layer 12 defines a first major surface 18 and a second major surface 20 opposite the first major surface. The plurality of particles 26 of the antimicrobial layer 12 at least partially form the first major surface 18. The plurality of particles 26 may also at least partially form the second major surface 20. The second major surface 20 is bonded to the support layer 14.

[0017] Each of the particles 26 comprises a bead 24 of a non-conductive material. As used herein, the term "bead" refers to a microspherical bead, which may be transparent, opaque, translucent, or colored. The beads 24 may be collectively described as having an average diameter. The average diameter may be 10, 20, 30, 40, 50, 60, 70, 80, 90, or even 100 micrometers or more. The average diameter may be 250, 200, 150, 100, 80, or even 60 micrometers or less. The size of the beads 24 may be selected, for example, to minimize the visual impact of the beads on the substrate.

[0018] The non-conductive material used to form the beads 24 may also be described as an electrically insulating material. Any suitable non-conductive material may be used to form the beads 24. Examples of non-conductive materials include, but are not limited to, one or more of glass, ceramic, non-conductive metal oxides, cellulose or modified cellulose, and electrically insulating polymers.

[0019] The non-conductive material may also be selected to provide a scratch resistant major surface for the antimicrobial layer 12. In some embodiments, the non-conductive material may be selected to have a Mohs hardness of 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, or even 8 or greater. For example, glass has a Mohs hardness of about 5.5.

[0020] The plurality of particles 26 may be dispersed in any suitable manner to form first major surface 18. In some embodiments, the plurality of particles 26 is formed as a monolayer, which may be described as a single layer of particles.

[0021] At least some of the particles 26 include a coating of conductive material 22 and may be described as conductive particles. In particular, the first set of particles may include beads coated with a first conductive material. Any suitable conductive material 22 suitable for coating the beads may be used. The conductive material 22 may promote metal ion release or galvanic microcurrents. Non-limiting examples of materials that may be used for the conductive coating material include Ag, Au, Pt, Pd, Ir, Cu, Sn, Sb, Bi, Zn, complexes and colloids thereof. Metal oxides of the conductive coating material may also be used.

[0022] The conductive coating of the conductive material 22 may have any suitable thickness. The coating thickness may be 2, 10, 20, 50, 70, 100, or even 500 nanometers or more. The coating thickness may be 1000, 500, 100, 70, 50, 20, or even 10 nanometers or less. The conductive coating may be continuous or discontinuous on the bead 24 to at least partially form the outer or exposed surface of the particle 26. In some embodiments, the particular non-conductive material of the bead 24 and the particular conductive material 22 may be selected such that when a thin coating of the conductive material 22 is applied to the bead 24, a discontinuous coating may be provided that still provides antimicrobial properties. For example, for some particles, a coating of less than 10 micrometers, or even less than 20 micrometers may be discontinuously coated. The coating thickness may be selected to provide the antimicrobial article with ion release and galvanic microcurrent properties for a period of time suitable for application of the article, such as the desired degree of metal ion release or galvanic microcurrent required over a period of time. The coating may be applied to the beads in any suitable manner, including physical vapor deposition techniques such as vacuum deposition, sputtering, magnetron sputtering, and ion plating. Suitable physical vapor deposition techniques may include, for example, those described in U.S. Patent Nos. 4,364,995, 5,681,575, and 5,753,251.

[0023] Coated particles may be fully coated or partially coated. In partially coated particles, at least a portion of the bead surface is exposed. In some embodiments, at least 5%, 10%, 20%, 30%, 50%, or 70% of the particle surface is exposed or uncoated. In some embodiments, no more than 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the particle surface is exposed or uncoated.

[0024] More than one coating of conductive material 22 may be used. In some embodiments, the second set of particles includes beads coated with a second conductive material. The second conductive material may have a different electrical potential than the first conductive material. For example, the first conductive material may include Ag or Cu, and the second conductive material may include the other Cu or Ag.

[0025] The first and second sets of particles 26 may be dispersed in any suitable manner relative to one another throughout the antimicrobial layer, which may be a monolayer, hi some embodiments, the first and second sets of particles 26 may be randomly dispersed throughout the first major surface (see Figures 3 and 4).

[0026] In some embodiments, at least some of the particles 26 are not coated with a conductive material and are described as non-conductive particles. A third set of particles may not be coated with a conductive material. For example, some of the particles may include bare, uncoated beads 24. Any suitable amount of conductive particles relative to non-conductive or uncoated particles may be used. Generally, the percentage of particles 26 that include beads 24 coated with a conductive material is 5%, 10%, 15%, 20%, 25%, 40%, 50%, 75% or more, or even 100% or more of the total number of the plurality of particles.

[0027] The conductive and non-conductive particles 26 may be dispersed amongst one another in any suitable manner throughout the antimicrobial layer, which may be a monolayer, in some embodiments, at least some of the conductive particles may be randomly dispersed amongst the non-conductive particles, or vice versa (see Figures 3 and 4).

[0028] The antimicrobial article 10 may also be more effective than existing technologies by concentrating the conductive material at a contact surface, such as first major surface 18. Portions of the conductive material 22 may also be protected from being removed by abrasion by the contours of the beads 24. Figure 2 shows particles 26 after some of the coating of conductive material 22 has been abraded off of the beads 24. The conductive material 24 still remains in the valleys between the beads 24, facilitating the release of ions or galvanic microcurrents.

[0029] FIG. 3 shows antimicrobial layer 40 having a first set of coated particles, a second set of coated particles, and a third set of uncoated particles. FIG. 4 shows antimicrobial layer 50 also having a first set of coated particles, a second set of coated particles, and a third set of uncoated particles. In the figure, the coated particles have stronger and darker features, while the uncoated particles appear relatively more faded with lighter gray features. However, antimicrobial layer 50 (FIG. 4) has a higher ratio of coated particles compared to uncoated particles than antimicrobial layer 40 (FIG. 3). In other words, antimicrobial layer 50 has a higher percentage of particles coated with conductive material than antimicrobial layer 40. In the illustrated embodiment, antimicrobial layer 40 has 80% uncoated particles, a first set of 10% coated particles (Cu), and a second set of 10% coated particles (Ag), while antimicrobial layer 50 has 50% uncoated particles, a first set of 25% coated particles (Cu), and a second set of 25% coated particles (Ag).

[0030] Barrier regions can be used to form an antimicrobial layer. Figure 5 shows an antimicrobial layer 100 having barrier regions 102 disposed between particles. The barrier regions 102 may at least partially form a first major surface of the antimicrobial layer. The barrier regions 102 may also at least partially form a part of a monolayer with the particles when the particles are arranged to form a monolayer.

[0031] The barrier region material can be applied in any suitable pattern or shape, including regular and irregular shapes, linear and curvilinear shapes, continuous and discontinuous patterns, random and repeating patterns, and combinations thereof. The barrier regions 102 can have large or small surface areas. The predetermined pattern of barrier regions 102 and particles can be arranged to have a desired visual effect or so that the pattern is invisible to the naked eye.

[0032] The barrier region 102 may be formed using any suitable barrier region material. As used herein, the term "barrier region material" means a material that substantially prevents beads 24 (FIGS. 1 and 2) from adhering to the layer to which it is applied, such as a polymeric support layer. The barrier region material may be permanent, semi-permanent, or temporary. Non-limiting examples of barrier materials include waxes, resins, polymeric materials, inks, inorganics, ultraviolet light curable (UV curable) polymers, particles composed of either organic or inorganic metallic or non-metallic materials, or photoresists.

[0033] Any suitable size of barrier region 102 may be used. In some embodiments, the area of ​​the barrier region 102 forming the first major surface may be 5%, 10%, 15%, 20%, 25%, 40%, 50%, 75%, or even 90% or more of the total surface area of ​​the first major surface. Further examples of techniques and materials related to the creation and use of barrier regions can be found in U.S. Pat. No. 10,845,514 (Chen-Ho et al.).

[0034] The antimicrobial article can be made in any suitable manner. In one example, some beads can be coated with a thin layer of a first conductive material, other beads can be coated with a thin layer of a second conductive material, and further beads can be left uncoated. The beads can be selected from the same or similar size distribution (e.g., the same average diameter). The beads can also be filtered before or after coating to achieve the same or similar size distribution. The beads can be applied to a support layer, such as a polymer adhesive or a membrane. The support layer, which can be an adhesive, can be applied to a substrate, such as a membrane or a fabric.

[0035] The antimicrobial article can provide antiviral or antimicrobial properties through any suitable mechanism, which may include metal ion release or galvanic microcurrent effects when applying a liquid, such as an electrolyte, to the first major surface. Applying a liquid may include application of moisture from ambient air, which may be provided from the surrounding environment. Metal ion release can be controlled by applying an electrolyte or fluid to the first major surface, for example, using metal oxides. Galvanic microcurrent effects can be controlled, for example, by the number of conductive particles forming the first major surface, the potential between different coating materials, and by application of an electrolyte to the first major surface.

[0036] The ability to achieve the release of atoms, ions, molecules, or clusters of the conductive material (e.g., metal) on a sustainable basis can be influenced, for example, by varying the amount of oxygen-containing gas during deposition. Increasing the level of oxygen-containing gas introduced increases the amount of metal oxide, which in turn can increase the metal ions released from the article. Thus, a higher weight percentage of metal oxide can enhance the release of antimicrobial agents, such as metal ions, for example, and can improve antimicrobial activity. When the first major surface is contacted with an alcohol or water-based electrolyte, the conductive material can release ions, atoms, molecules, or clusters. A concentration of the conductive material sufficient to produce an antimicrobial effect can be selected based on the particular conductive material and electrolyte.

[0037] The ability to generate at least one galvanic microcurrent (e.g., electric current) when introduced into an electrolyte can be influenced by the conductive material selected, particularly by their potential difference. Depending on the material selected, if electrons flow from the second conductive material to the first conductive material, the first conductive material can be the cathode (positive electrode) and the second conductive material can be the anode (negative electrode), or vice versa. Redox reactions and ion flow can occur in the presence of the electrolyte, thereby generating an electric current between the first and second conductive materials. The electric current can be influenced by the amount of conductive particles involved in the ion flow. These currents can inhibit the growth of microorganisms such as bacteria and viruses.

[0038] The antimicrobial article may be capable of generating a current of 10, 50, 100, 250, 500, 1000, or even 2500 microamps (μA) or more when introduced into an electrolyte solution. The antimicrobial article may be capable of generating a current of 5000, 2500, 1000, 500, 250, 100, or even 50 μA or less when introduced into an electrolyte solution. EXAMPLES

[0039] Unless otherwise stated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and elsewhere in the specification are by weight. [Table 1]

[0040] Bacterial and phage materials Soft TSB agar was prepared by adding 40 grams of TSB powder and agar (7.5 g) to deionized water (1 L). The resulting product was autoclaved (121°C for 15 min). Before use, the soft agar was melted using a microwave oven and 0.05 mL of 1x10 agar was added per plate. 8 Pseudomonas strain (DSM 21482) was added.

[0041] LB agar plates were prepared by adding LB agar powder (35 g) to deionized water (1 L), autoclaving the mixture (121 °C for 15 min), and pouring 15 mL of the molten gel mixture onto the plate. LB broth was prepared by dissolving LB broth powder (20 g) in deionized water (1 L) and autoclaving the mixture (121 °C for 15 min). TSB broth was prepared by suspending Tryptic Soy broth powder (30 g) in deionized water (1 L) and autoclaving the mixture (121 °C for 15 min).

[0042] Phi 6 phage was harvested from liquid TSB cultures of its host Pseudomonas strain grown in shake flasks at 25° C. in a shaker at 250 RPM for at least 8 hours.

[0043] Bacterial strains were inoculated into LB broth and grown in tubes at 25°C, 250 RPM in a shaker for at least 12 hours.

[0044] Staphylococcus aureus subsp. Rosenbach strain (ATCC 6538) was inoculated into TSB broth and grown at 25°C and 250 RPM in a shaker for at least 12 hours.

[0045] Escherichia coli (Migula) Castellani and Chalmers strain (ATCC 25922) was inoculated into TSB broth and grown at 25°C and 250 RPM in a shaker for at least 12 hours.

[0046] Glass beads Two types of metal coated glass beads were prepared separately using the following method: Cu coated glass beads and Ag coated glass beads for the examples shown in Table 1. The glass beads were calcined at 150° C. for at least 8 hours and then placed in a vacuum chamber (commercially available from Sierra Applied Sciences) equipped with a 300 mL particle stirrer and a 3-inch diameter metal sputtering target and cathode. During deposition, the particle stirrer was operated at about 4 revolutions per minute (rpm). The chamber was pumped down to base pressure and the metal was sputtered at a pressure of about 4 milliTorr (mTorr) using argon gas (99.999% purity). The argon flow rate was 100 standard cubic centimeters per minute (sccm). The metal was sputtered at the desired settings to produce a thin film coating of the metal on the surface of the beads. The coated beads were filtered through a 120 mesh filter. The copper coating was estimated to constitute 2.06% of the final weight of the Cu coated glass beads. The silver coating was estimated to comprise 1.60% of the final weight of the Ag-coated glass beads. [Table 2]

[0047] Examples 1 to 10 and Comparative Example 1 Examples were prepared with the glass bead amounts and oven temperatures in Table 2 as follows: The diameter of the glass beads was 60-100 micrometers. Coated and uncoated glass beads according to Table 2 were mixed in a glass or metal beaker and heated in an oven until the glass bead mixture reached oven temperature. A thermocouple probe was used to measure the temperature of the glass bead mixture. The heated mixture was then cascaded onto and settled into the polyethylene layer of a bead carrier liner. The bead carrier liner was prepared as described in U.S. Pat. No. 5,474,827, with a 20-50 micrometer polyethylene layer coated onto a paper backing. The settling depth was less than the diameter of the glass beads. A portion of the glass bead mixture remained exposed on the surface of the polyethylene layer. [Table 3]

[0048] Example 11: Cu-coated PET film Cu films were deposited on a 10.16 cm x 10.16 cm square sheet of PET film. One side of the PET sheet was primed. Metal was deposited on the primed surface of the PET film. Deposition was carried out using a PVD75 vacuum deposition chamber (Kurt J Lesker, Jefferson Hills, PA, USA). Cu films were deposited using RF sputtering. The power source was a Kurt J Lesker model R301 RF power supply. The chamber was powered at 3.3 x 10 -6 The chamber was pumped down to a base pressure of less than 10 Torr. Ultra-high purity argon gas was flowed into the chamber at a flow rate of approximately 51 sccm. The operating pressure was approximately 4.1 × 10 -3 Torr. Cu was sputtered at a set point of 200 Watts. Reflected power was 2.0 Watts. The substrate was rotated at 20 rpm on the chamber platen. Deposition was carried out for 715 seconds, resulting in an estimated coating thickness of approximately 100 nm.

[0049] Example 12: Ag-coated PET film Ag films were deposited on a 10.16 cm x 10.16 cm square sheet of PET film. One side of the PET sheet was primed. Metal was deposited on the primed surface of the PET film. Deposition was carried out using a PVD75 vacuum deposition chamber (Kurt J Lesker, Jefferson Hills, PA, USA). Ag films were deposited using DC magnetron sputtering. The chamber was fitted with a 5.0x10 -6 The chamber was pumped down to a base pressure of less than 10 Torr. Ultra-high purity argon gas was flowed into the chamber at a flow rate of approximately 51 sccm. The operating pressure was approximately 4.1 × 10 -3 Torr. Ag was sputtered at a set point of 200 watts (300 volts, 0.67 amps). The substrate was rotated at 20 rpm on the chamber platen. Deposition was carried out for 170 seconds, resulting in an estimated coating thickness of approximately 100 nm.

[0050] Example 13: Article with a fabric backing: The bead-coated liner (Example 9) was coated with a polyester adhesive (50% solids polyester resin commercially available from Bostik Company, Wausatosa, Wis. as "VITEL 3550 B") to a wet thickness of 8 mils, subsequently heat-treated at 190° F. for 30 seconds, laminated to a 100% polyester fabric (2.25 oz / sqyd, Milliken and Co.), and then heat-treated for 6 minutes at 210° F. Following the heat-treatment process, the carrier layer was peeled away to expose the pre-embedded surface of a single layer of glass microspheres to produce an article with a fabric backing.

[0051] Example 14: Article with extensible hot melt adhesive backing: The bead-coated liner (Example 9) was coated with a polyester adhesive (50% solids polyester resin commercially available from Bostik Company, Wausatosa, WI as "VITEL 3550 B") to a wet thickness of 8 mils, followed by heat treatment at 190°F for 30 seconds and 210°F for 6 minutes. After heat treatment, the exposed surface of the coated adhesive layer was laminated to an extensible hot melt adhesive (Bemis 3419, Bemis Associates Inc.). Following the lamination process, the carrier layer was peeled off, creating a co-compliant article with an exposed pre-embedded surface of a single layer of glass beads.

[0052] Measurement of small current Examples 1-3 were cut into sample specimens measuring 2.54 cm x 5.08 cm. The sample specimens were pre-moistened with Eyesaline (Honeywell, Charlotte, North Carolina). Microcurrents were then measured using an OTII-ARC-001 multimeter (Scheelevagen, Sweden) equipped with a two-point probe, as shown in Table 3. [Table 4]

[0053] Bacterial death test The modified ISO 22196:2011 method "Measurement of Antibacterial Activity on Plastic and Other Non-Porous Surfaces" was used to evaluate the antibacterial properties of the example articles. "Bacterial Killing Test" refers to this method as described herein. Examples 1-12 were cut into circular specimens with a diameter of 2.54 cm, n=3. A 25 microliter inoculum of bacteria, such as bacterial strains, gram-positive strains, or gram-native strains, was prepared in phosphate buffer at a concentration of 1×10E8 to 1×10E9 colony forming units / mL (cfu / mL) for use in the test.

[0054] The test specimens were contacted with the bacteria by placing the inoculum between the test material and a sterile microscope slide cover and incubated at room temperature for 1 hour and / or 6 hours. Comparative Example 1 test specimens with a non-antimicrobial surface were treated with the inoculum. After incubation, the test specimen samples were neutralized in Dey\Engley Neutralizing Broth (obtained from Becton Dickinson Company, Franklin Lakes, NJ) and the viable cell count was accessed using the plate count culture method. In the plate count culture method, viable bacteria were counted by performing 10-fold serial dilutions. An aliquot of each dilution was plated on LB plates or 3M™ PETRIFILM™ Rapid Coliform Count Plates. The plates were incubated at 37°C for 16 hours. The colonies on the LB plates were counted manually and reported in Table 4. The colonies on the Rapid Coliform Count Plates were counted with a 3M™ PETRIFILM™ Plate Reader Advanced and reported in Table 5.

[0055] Virus killing test Viral killing tests for antiviral activity were performed using bacterial phages as surrogates. The modified ISO22196:2011 method "Measurement of Antibacterial Activity on Plastic and Other Non-Porous Surfaces" was used to evaluate the antiviral properties of the example articles. "Viral Killing Test" refers to this method described herein. Examples 1-8 were cut into circular specimens with a diameter of 2.54 cm and n=3. 25 microliters of Phi 6 phage solution at 10E10 pfu / mL was used for the assay.

[0056] The test specimens were contacted with the virus by sandwiching the virus between the test material and a sterile microscope slide cover and incubated at room temperature for 10 minutes. Comparative Example 1 test specimens with a non-antimicrobial surface were treated with the inoculum. After incubation, the test specimen samples were neutralized with 10 mL of Dey\Engley neutralizing broth and evaluated for live Phi 6 phage counts using the plate count culture method. In the plate count culture method, live Phi 6 phage were counted by performing 10-fold serial dilutions. An aliquot (100 microliters) of each dilution was plated on a TSB soft agar plate containing a Pseudomonas strain (DSM 21482). The plates were incubated at room temperature for at least 8 hours. Phage plaques were counted manually and reported in Table 4. [Table 5] [Table 6]

[0057] Scratch and bacterial killing tests Examples 9-12 were individually tested for scratch resistance using a TABER Model 5750 Linear Abrader (Taber Industries, North Tonawanda, NY). First, a 2.5 cm x 5.0 cm section of SCOTCH-BRITE™ Hand Pad 7447 (3M Company, St. Paul, MN) was adhesively attached to the bottom of the instrument's test arm and used as the abrasive material in the test. Each example (10 cm x 10 cm) was adhesively attached to a horizontally positioned glass surface, exposing the metal-coated surface for contact with the abrasive pad. In operation, an abrasive pad was placed in contact with the metal-coated surface and operated in a linear reciprocating motion across the metal-coated surface with an 825 gram load attached to the top end of the test arm for 50 cycles (at a rate of 60 cycles / minute). Each example was then rotated 90 degrees and abraded under the same conditions for an additional 50 cycles. Second, a 2.5 cm x 5.0 cm section of SCOTCH-BRITE™ Hand Pad 7448 (3M Company, St. Paul, Minn.) was attached to the bottom of the instrument's test arm and the same areas of each example were abraded at 0 degrees and 90 degrees, respectively, for 100 cycles. Third, a 2.5 cm x 5.0 cm section of 3M TRIZACT™ HOOKIT™ Finishing Foam Disc, 3000 (3M Company, St. Paul, Minn.) was attached to the bottom of the instrument's test arm and the same areas of each example were abraded at 0 degrees and 90 degrees, respectively, for 100 cycles.

[0058] The resulting abraded Examples 9-12 were then tested for bacterial kill with bacterial and gram-negative strains according to the bacterial kill test described above. The results are reported in Tables 6 and 7. [Table 7] [Table 8]

[0059] Thus, various embodiments of antimicrobial surfaces with conductive particles are disclosed. Reference is made herein to the accompanying series of drawings, which form a part of this disclosure, and at least one skilled in the art will appreciate that various adaptations and modifications of the embodiments described herein are within or do not depart from the scope of the present disclosure. For example, aspects of the embodiments described herein can be combined with each other in various ways. It is therefore to be understood that within the scope of the appended claims, the claimed invention may be practiced otherwise than as expressly described herein.

[0060] All scientific and technical terms used herein have the meanings commonly used in the art unless otherwise specified. The definitions provided herein are intended to aid in the understanding of certain terms used frequently herein and are not intended to limit the scope of the present disclosure.

[0061] Unless otherwise indicated, all numbers expressing feature sizes, quantities, and physical properties used in the specification and claims can be understood as being modified by either the term "exactly" or "about." Accordingly, unless specifically indicated to the contrary, the numerical parameters set forth in the above specification and appended claims are approximations that can vary depending upon the desired properties sought to be obtained by those of ordinary skill in the art utilizing the teachings disclosed herein, for example, within typical ranges of experimental error.

[0062] The term "or" is generally used in its inclusive sense, e.g., meaning "and / or," unless the content clearly indicates otherwise. The term "and / or" refers to one or all of the listed elements or a combination of at least two of the listed elements.

Claims

1. The supporters and 1. An antimicrobial article comprising: an antimicrobial layer having a first major surface formed at least in part by a plurality of particles and a second major surface bonded to the support layer, wherein each particle of the plurality of particles comprises a bead of a non-conductive material, and a first set of the particles comprises beads coated with a first conductive material.

2. the first major surface is a log reduction in bacteria of 2 or greater one hour after application to said first major surface; and 10. The article of claim 1, wherein the article is configured to provide at least one of: a log reduction of viruses of 2 or greater 10 minutes after application to the first major surface.

3. The article of claim 1 or 2, wherein the second set of particles comprises beads coated with a second conductive material having a different electrical potential than the first conductive material.

4. 4. The article of claim 3, wherein a current of at least 10 microamps is generated when the first major surface is coated with an electrolyte.

5. The article of claim 3 , wherein the first conductive material comprises Ag and the second conductive material comprises Cu.

6. The article of claim 1 , wherein the first conductive material comprises Cu.

7. The article of claim 1 , wherein the plurality of particles are arranged to form a monolayer.

8. The article of claim 1 , wherein the third set of particles is not coated with a conductive material.

9. 10. A method of using the article of claim 1, comprising applying a liquid to said first major surface of said article, said liquid optionally being an electrolyte.

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