CA2952134A1 - Anti-bacterial leg bands for the prevention of footrot, interdigital dermatitis and other bacterial infections in livestock - Google Patents

Abstract

Durable articles applied to the body of animals containing metallic materials providing antimicrobial properties are disclosed. Articles may comprise grain-refined and/or amorphous metals, e.g., copper, cobalt, tin and zinc, or their combinations, in contact with a fluid absorbent material. Optionally the article comprises complexing agents, gelling agents, end of life indicators and the like to extend their effectiveness under various conditions and signifies depletion of their biocidally active ingredients. Articles may be leg bands, pads, bandages, band aids or wraps.

Description

Dec 19, 2016 Integran Technologies Inc. # 6252 Anti-Bacterial Leg Bands for the Prevention of Footrot, Interdigital Dermatitis and Other Bacterial Infections in Livestock FIELD OF THE INVENTION
Exemplary embodiments herein relate to articles comprising an aqueous fluid absorbent material in contact with a grain-refined and/or amorphous, biocidal, metallic material. The metallic material slowly release metal ions in contact with water and bodily fluids, and provides anti-microbial, antibacterial, anti-fungal and/or anti-viral properties to live stock.
BACKGROUND OF THE INVENTION
A number of pure metals including mercury, silver, copper, iron, lead, zinc, cobalt, lead, bismuth, gold, and aluminum are known to exhibit antimicrobial behavior.
The bactericidal characteristics of these and other metals have been recognized centuries ago and exploited for many years, the two most commonly used being silver and copper.
For example, silver-based ointments have been used in burn centers for over a century, and silver coated water storage tanks in ships and airplanes are known to maintain the water quality for extended periods of time. Copper is commonly used in fungicides, antifouling paints, antiseptics and has also been used as an air conditioning tubing material to suppress Legionnaire's disease. In addition, copper and many of its alloys have been used effectively against E. coli and methicillin-resistant Staphylococcus aureus (MRSA), Salmonella enteric, and even West Nile virus and HIV-1.

- 2 -It is commonly believed that antimicrobial metals function by inhibiting the expression of enzymes and other proteins essential to the production of adenosine 5'-triphosphate (ATP), an essential component of cell metabolism. Studies on silver suggest that silver ions denature proteins (enzymes) of the target cell or organism by binding to reactive groups, resulting in their precipitation and inactivation.
While the precise mechanism by which metals are able to kill bacteria is not well understood, it is apparent that the antimicrobial method of action is related to the dissolution characteristics of the metal. In other words, the bactericidal efficacy is linked to the ability of the metal-containing surface to release its constituent metallic ions at effective antimicrobial concentrations when placed in contact with the target bacteria-containing medium or bio-fluid.
Effective, sustained metallic ion release can be accomplished in a number of ways. For instance, the metal may be processed as a fine particulate and finely dispersed at an appropriate concentration throughout a suspending media. In this way, the surface to volume ratio of the metal is maximized and antimicrobial efficacy thereby enhanced.
Colloidal silver, a suspension of microscopic silver particles in water, is a common example of this technique that is frequently used as a disinfectant in hospitals. Metal-containing ointments and creams function by a similar means. This method, however, generally requires frequent re-application of the metal-containing fluid in order to ensure sustained metal ion release at the region of interest since metallic antimicrobial colloids, ointments and creams are easily rendered inactive by reaction and complexation with bio-fluids.
Bauer et al in U.S. Pat. No. 4,031,208 (1977) teach methods for preparing and using antibiotics' comprising organic compounds consisting of C, H, and 0, and containing methoxy groups, which are poorly soluble in water and can contain ions of trace elements such as Cu, Fe, Mn, Mo, Zn, Co and Ni, both therapeutically and for promoting livestock growth.

- 3 -Sustmann et al in U.S. Pat. No. 4,675,014 (1987) teach a method for absorbing bodily secretions while hindering the generation of odors and growth of microbes comprising applying a fibrous mass having copper cations bound through selected anions, preferably carboxymethyl, the amount of chemically bound copper being between 0.1 and 3% by weight. The fibrous mass can be in the form of a catamenial device, bandage, diaper, shoe liner, or the like.
Code in U.S. Pat. No. 7,867,510 (2011) teaches articles applied to the body of an animal (including humans) to provide both absorbency and antimicrobial activity. The article may comprise a water absorbent material; and a composition that reacts with water to produce molecular iodine. The article may be a diaper, sanitary pad, bandage, bandaid or wrap for an animal.
The requirement for frequent replacement or replenishment of metal-containing ointments, creams and/or colloids based upon antimicrobial metal in particulate form may be overcome by a second means to optimize metallic ion release, namely via the formation of metallic microstructures that are intrinsically active in bulk, fully-dense form. In other words, the desired unassisted antimicrobial behavior is a function of the inherently high surface activity of the metallic material's microstructure and is therefore sustained at a dissolution rate commensurate with effective antimicrobial surface performance as long as the metallic surface remains exposed to the bacteria-containing medium, bio-fluid, etc. Burrell et al. in U.S. Pat. No. 5,753,251 (1998), 5,681,575 (1997), 5,837,275 (1998), 6,238,686 (2001) and 6,365,220 (2002) teach the synthesis of antimicrobial metals that exhibit enhanced antimicrobial activity that is intrinsic to the bulk metal by virtue of its high stored internal energy. The sustained ionic dissolution rate is due to the ultrafine-grained microstructure of the metallic films. It is noteworthy, however, that Burell's definition of "metals" is not limited to what is generally accepted to represent "metallic materials", i.e., metals and alloys, but is significantly expanded to also include electrically non-conductive metal compounds such as oxides, nitrides, borides, sulfides, halides and hydrides. The enhanced, sustained anti-microbial effect is

- 4 -associated with the processing of metals and alloys in fine-grained form, however, the material processing technique of Burrell et al. is based upon vapor deposition methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD).
While such techniques are suitable for the synthesis of fine-grained anti-microbial materials, they are wholly unsuitable for the production of highly abrasive wear, scratch and scuff-resistant surfaces as the resulting vapor deposited coatings are generally thin (typically <
micron thickness), porous (<99% theoretical density) and are oftentimes relatively soft (<200 VHN).
To satisfy the basic durability requirements needed in numerous applications, the 10 inherent mechanical property limitations of thin sputtered antimicrobial films must be overcome. This necessitates the use of a processing technique capable of producing fine-grained metallic materials that exhibit the desired sustained release of metal ions inherent to fine-grained microstructures while simultaneously exhibiting good hardness, strength, toughness, scratch resistance, abrasive/sliding wear, and scuff resistance properties.
U.S. Pat. No. 5,352,266 (1994), U.S. Pat. No. 5,433,797 (1995), PCT/EP02/07023 (2002) and DE 10108893 (2002), assigned to the same applicant, teach fine-grained (<0.3 micron average grain size) metals and alloys offering improved resistance to permanent mechanical deformation as compared to either the aforementioned thin vapor deposited coatings or chemically equivalent metals or alloys fabricated in coarse-grained form (>0.3 micron grain size) preferably made by electrodeposition. Palumbo et at.
in U.S.
Pat. No. 9,260,790 (2015), assigned to the same applicant, teach a method of producing polycrystalline ultrapure grain-refined copper materials having improved mechanical and physical properties by electrodeposition from alkaline pyrophosphate solutions. Facchini et at. in U.S. Pat. No. 8,691,397 (2014), assigned to the same applicant, disclose anti-microbial properties of grain-refined Co-comprising metallic coatings.
It is well known that animals that are in pain do not eat well, do not convert feed into meat as well, and do not breed as well as healthy animals. It should be noted that thrush and foot rot in cattle is one of the biggest causes of economic loss for the cattle

- 5 -industry. Presently, the most often used remedy for foot rot, a bacterial disease of the feet in hoofed animals, is copper sulfate foot baths. Similarly, mild superficial infections of the skin of animals between the claws are also typically treated by confining the affected animals in a 5% copper sulfate foot bath for an hour, twice-daily for a number of weeks.
It is against this background that the need arose to develop the articles described herein.
SUMMARY OF THE INVENTION
to At the present time no satisfactory preventive devices or treatments are available designed to prevent bacterial infections in animals from occurring for extended periods of times. It is therefore an object of the invention to provide a durable, preventive medical device for livestock designed, in the presence of water and bio-fluids, to slowly form and/or release antibacterial compounds in sufficient concentrations to reduce the risk of infections and ideally avoid infections altogether for extended periods of times, e.g., several weeks to several months.
It is also known that salts of heavy metals, capable of providing antibacterial properties, when dissolved in aqueous fluids, can be rapidly precipitated by organic or other material contained in bio fluids and at pH levels exceeding 7.
Therefore, while such salts may have good initial antimicrobial properties at an initially effective metal ion concentration, their effective concentration in the fluid can drop rather quickly by the reaction of metal ions with such extraneous matter, thereby depleting the amount of metal ions available for biocidal activity. While, e.g., inorganic water-soluble metal salts appear to offer suitable biocidal infection protection, they may be rendered ineffective rather quickly when applied to livestock's feet and the sustained metal ion release in antimicrobial concentrations required to ensure prolonged destruction and/or inhibition of bacterial infections is not achieved.

- 6 -Accordingly, the present invention provides articles comprising grain-refined and/or amorphous, biocidal, metallic materials produced, e.g., by electrodeposition, which, in the presence of bio-fluids corrode releasing metal ions, thereby exhibiting anti-microbial, antibacterial, anti-fungal and/or anti-viral behavior for extended periods of time while exhibiting enhanced mechanical durability.
Livestock's feet can be exposed to a variety of environments, ranging from totally dry conditions with no fluid present to dissolve and release biocidal metal ions in antimicrobial concentrations to totally wet conditions, quickly dissolving and potentially too quickly releasing all biocidal metal ions contained in a device attached to the legs of animals, e.g., in water soluble salts. At one extreme, in totally dry conditions, no metal corrosion takes place releasing biocidal metal ions. It is therefore an object of the invention to regulate the moisture content in the preventive medical device to avoid too much or too little formation and/or release of the biocidal active compound(s). Ideally, the antimicrobially active device is at least periodically exposed to sufficient fluid to leach sufficient metal ions from the active material to maintain the biocidal properties, such as in the case of dairy cows, which tend to get hosed down with water every day after milking.
It is one objective of the present invention to utilize fine-grained metallic materials and/or amorphous metallic materials produced by electrodeposition in the preventive medical device to provide the biocidal properties. It is to be understood that usage of the term electrodeposition implies electrochemical reduction of metal by either electrolytic (electroplating) or autocatalytic (electroless plating) means. In principle, any electrodeposition-based technique that is suitable for the production of fine-grained metals and alloys can be employed. In particular, both direct current (DC) and pulsed current electrolytic deposition are uniquely suited as the plating conditions can be adjusted to conveniently achieve the desired property or selected properties.
Suitable methods of electroplating include tank, barrel and brush plating. Metal matrix composites (MMCs) can also be produced by electrodeposition by suitably suspending particles in the plating bath resulting in the incorporation of the particulate matter in the

- 7 -electrodeposit by inclusion. Alternatively, grain-refined and/or amorphous metallic materials can be formed by electroplating porous structures including foams, felts, clothes, perforated plates and the like.
It is well known that during electrodeposition the metallic layer is formed by the continuous and sustained reduction of metal ions onto the substrate surface, which is a cumulative process. As such, the fine-grained microstructure with an average grain size between 2nm and 300nm in the deposit stretches over a cross-sectional layer thickness of at least 2nm, preferably 0.5 micron, and more preferably 10 micron. The thickness of the metallic layer(s) can extend as far as 25mm in thickness, but typically is less than lmm, to preferably between 0.01 and 0.5mm. The metallic material thickness is chosen to provide sufficient material to supply biocidal ions for weeks to months, however, it is also important the thickness of the material still malleable/flexible, and can readily deformed/bent when, e.g., the leg band is applied to an animal leg.
It is an objective of the present invention to provide metal-coated or free-standing articles comprising fine-grained and/or amorphous metallic layers comprising Cu, Co, and Zn, or combinations thereof, having a porosity of preferably of equal to or less than 1.5%, a layer thickness of at least 0.010mm, preferably greater than 0.025mm, more preferably greater than 0.050mm and even more preferably greater than 0.10mm to ensure the device remains biocidally active for at least one month.
It is another objective of the present invention to optionally provide metallic layers that are porous or suitably perforated to allow for adequate fluid flow, with a porosity of least 1%, preferably at least 5% and even more preferably at least 10%.
It is another objective of the present invention to provide grain-refined metallic layers comprising at least one metal which dissolves in contact with fluids, that are made from a single, coherent, and active metal structure and that do not consist of loose flakes, chips, plates, powders or metal rounds that, with extended use and dissolution, reduce in size, lose physical contact with each other and are prone to plug the absorbing outer fabric material impeding fluid flow. The present disclosure also contemplates using

- 8 -distinct coherent metallic structures for more than one metal/alloy composition incorporated into and integrated with the article. In the case of using metal flakes, powders and the like, coherent "metallic bands" are formed by using, e.g., an organic binder.
It is an objective of the present invention to provide a novel article which comprises durable anti-microbial layers or coatings of pure metals or alloys of metals selected from second to fifth main group of the periodic system and the transition elements including Cu, Co, Sn, Fe, and Zn and optionally further alloying elements selected from B, C, P. Mo, S and W and metal matrix composites of pure metals or alloys with particulate additives such as powders, fibers, nanotubes, flakes, metal powders, metal alloy powders and metal oxide powders of Al, Co, Cu, In, Sn and Zn. The particulate average particle size is typically below 10 micron, more preferably below 1 micron, and more preferably below 0.1 micron. Electrodeposition can be employed to create anti-microbial coatings on metallic components, or non-conductive components that have been metallized to render them suitable for electroplating.
Alternatively, a stand-alone article on a mandrel or other suitable temporary substrate can be electroformed and, after reaching the desired plating thickness, the free-standing electroformed article can be removed from the temporary substrate.
It is another objective of the present invention to provide biocidally active metallic materials comprising a single or several fine-grained and/or amorphous metallic layers comprising at least on element selected from the group consisting of Cu, Co, Sn and Zn, including multi-layer laminates produced in a single tank by electrodeposition composed of, e.g., alternating layers of fine-grained and/or amorphous metallic layers, layers comprising differences in chemical composition, including, but not limited to, a high-Cu, low-Zn brass layer followed by a Zn-rich, low Cu alloy layer and the like.
It is another objective of the present invention to provide biocidally active metallic materials which are substantially free of Ag and toxic or potentially toxic metals, including, but not limited to, Ni, Cr, Pb, Sb and As.

- 9 -It is an objective of the present invention to optionally provide suitable substrates to serve as the carrier for the antimicrobial metallic material(s) and/or to incorporate indicator materials, complexing agents or gelling agents.
It is another objective of the present invention to optionally utilize a variety of additives/substances in the preventive medical device aimed at ensuring that the biocidal properties of the metallic materials are maintained under a variety of environmental conditions as well as over a wide range of compositions of bio-fluids. In addition, end of life indicators can be incorporated to signal the need for replacement of the preventive medical device.
It is another objective of the present invention to provide complexing agents to prevent the formation and precipitation of metal hydroxides at a pH>7.
It is an objective of the present invention to provide a leg band for livestock containing a complexing agent in the range of between 1% and 50% by weight of the leg band.
It is an objective of the present invention to provide an absorbent material capable of managing/regulating the moisture content in the preventive antibacterial medical device for animals and capable of influencing and preferably controlling the formations and/or release of the biocidal active compound(s).
It is an objective of the present invention to provide a leg band for livestock containing a fluid absorbing material in the range of between 1% and 50% by weight of the leg band.
It is an objective of the present invention to optionally utilize gelling agents to prevent the excessive release or "wash out" of antibacterially active compounds in case of very wet conditions resulting in excess fluids contacting the antimicrobial material(s).
It is an objective of the present invention to provide a moisture absorbing material impregnated with the gelling agent and/or to provide the metallic material which is partially or totally coated with the gelling agent with or without the use of a binder.

- 10 -It is an objective of the present invention to provide hygroscopic additives such as deliquescent materials to keep the device moist during dry conditions.
It is an objective of the present invention to provide an indicator or die material incorporated into the antibacterial medical device to conveniently signify the depletion of the biocidal active metallic material and signify the need to exchange the device, e.g., by affecting a color change.
Accordingly, in one embodiment, the present invention provides a flexible and removable device for fastening to the leg of an agricultural animal providing antimicrobial properties comprising:
(i) an outer fabric material capable of absorbing at least 5% of its own dry weight of water;
(ii) a metallic antimicrobial composition comprising at least one metal chosen from the group consisting of Co, Cu, Sn and Zn having a grain-refined microstructure with an average grain size of less than 10 microns and/or an amorphous microstructure, said metallic antimicrobial composition being a strip with or without perforations which is 5-50cm long, 1-10cm wide, and has a thickness to provide antimicrobial properties for a period of at least 1 month;
(iii) an indicator material reacting with water and/or bio-fluid resulting in a visible color change to signify the depletion of said a metallic antimicrobial composition; and (iv) means for securing said device to an animal leg.
In one embodiment, the present invention provides a flexible article for application to the body of an animal to provide both fluid absorbency and antimicrobial activity comprising:
(i) a permanent substrate which is electrochemically inert and pervious to fluid,

- 11 -(ii) a consumable antimicrobial active metallic insert which is fluid pervious provided on the permanent substrate and having a thickness between 1 and 500 microns, the consumable antimicrobial active metallic coating/layer comprising a consumable, antimicrobial active metallic material capable of being dissolved in said fluid and forming metal ions; and (iii) an electrically non-conductive, fluid pervious absorber positioned on and in intimate contact with the consumable antimicrobial active metallic insert;
wherein the consumable antimicrobial active metallic insert provides antimicrobial properties for a period of at least 1 month.
In one embodiment, the present invention provides an absorbent composite structure suitable for use in disposable absorbent articles for use on livestock, said composite structure comprising:
(i) an absorber in the range of between 1% to 50% by weight of the composite structure, said absorber being capable of absorbing at least 5% of its own dry weight of water;
(ii) a metallic antimicrobial composition in the range of between 5% to 95%
by weight of the composite structure, said metallic antimicrobial composition comprising at least one metal chosen from the group consisting of Co, Cu, Sn and Zn having a grain-refined microstructure with an average grain size of less than 10 microns and/or an amorphous microstructure, and a hardness exceeding 100VHN, said metallic antimicrobial composition being a strip with or without perforations which is 5-50cm long, 1-10cm wide, and having a thickness to provide antimicrobial properties for a period of at least 1 month;
(iii) an indicator material composition in the range of between 0% to 1% by weight of the composite structure, said indicator material capable of reacting with at least one fluid selected from the group consisting of water,

- 12 -bio-fluid, and synthetic urine resulting in a visible color change to signify the depletion of said a metallic antimicrobial composition;
(iv) a gelling agent in the range of between 0% to 1% by weight of the composite structure, said gelling agent capable of reacting with at least one fluid selected from the group consisting of water, bio-fluid, and synthetic urine to increase the viscosity of said fluid by at least 10%;
(v) a complexing agent for metallic ions, released from said metallic antimicrobial composition, in the range of between 0% to 50% by weight of the composite structure; and (vi) means for securing said absorbent composite structure to an animal leg.
Definitions:
As used herein, the term "agricultural animal" or "livestock" refers to animals raised on a farm including, but not limited to cows, horses, sheep, goats, pigs, and the like.
As used herein "biocidal agents" or "antibacterial agents" refer to agents that destroy living organisms, particularly microorganisms.
As used herein, the term "foot rot" refers to an infectious condition that causes swelling, heat and inflammation in cattle's feet, resulting in, at times, severe lameness.
Swelling and lameness can appear suddenly, with the animal walking normally one day but limping the next day. Lame cattle can lose weight quickly if they are reluctant to travel to feed and water.
As used herein, the term "interdigital dermatitis" refers to a mild superficial infection of the skin of animals between the claws occurring where cattle are densely concentrated. An effective treatment is an animal can be confined in a 5%
copper sulfate footbath for an hour, twice-daily for a number of weeks.

- 13 -As used herein, the term "bio-fluid" refers to liquids that animals, e.g., their feet, can be, at times, exposed to such as water containing bodily fluids or other contaminants present around livestock. Bio-fluids include water containing bacteria-containing fluids, water contaminated with body secretions such as urine and feces, water contaminated with natural and artificial fertilizers, pesticides, insecticides, and the like.
As used herein, the term "synthetic urine" refers to a liquid that is designed to be similar to human urine as, e.g., used to calibrate diagnostic equipment.
Typically, synthetic urine has a specific gravity in the range of 1.00-1.04, a pH in the range of 4-9 and a total solids content a in the range of 1.5-6% by weight. It necessarily contains urea, creatinine and water, and optionally includes uric acid, and a buffer, such as a phosphate buffer, phosphorus, potassium, calcium and a source of sodium. A simplified composition contains water with urea (6-9g/L), creatinine (0-3g/L), sodium sulfate (-2g/L), potassium chloride (-2g/L) and ammonium phosphate (1-2g/L). In another variation, the synthetic urine contains urea (6-9g/L), creatinine (3-30g/L), magnesium chloride (-0.5g/L), calcium chloride (-0.25 g/L), ammonium diphosphate (-0.85 g/L), ammonium phosphate (-0.85g/L), of sodium sulfate (-2g/L), and potassium chloride (-2g/L).
As used herein, the term "hygroscopic" refers to the ability of a substance to attract and hold water molecules from the surrounding environment. This is achieved through either absorption or adsorption. This could result in an increase in volume, boiling point, viscosity or other physical characteristic and properties of the substance, as water molecules attach to the substance's molecules in the process.
Hygroscopic substances include cellulose fibers (such as cotton and paper), many fertilizer chemicals, many salts (including table salt), and a wide variety of other substances.
As used herein, the term "deliquescent materials" refers to substances (mostly salts) that have a strong affinity for moisture and will absorb relatively large amounts of water from the atmosphere if exposed to it, forming a liquid solution.
Deliquescent salts include calcium chlorides of Ca, Mg, Fe, and Zn, as well as selected carbonates and

- 14 -phosphates. Many engineering polymers are hygroscopic, including polyamides, ABS, polycarbonate, cellulose, and poly(methyl methacrylate).
As used herein, the term "gelling agent" refers to substances added to fluids as thickening agents to raise their viscosity and provide the texture of a gel.
As used herein, the term "porosity" refers to a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0 and 100%. In the context of this disclosure porosity is a measure of the "accessible void", i.e., the total amount of void space accessible by a liquid from an outer surface.
As used herein, the term "metal", "alloy" or "metallic material" means crystalline and/or amorphous structures where atoms are chemically bonded to each other and in which mobile valence electrons are shared among atoms. Metals and alloys are electric conductors; they are malleable and typically form positive ions. Metallic materials include Co¨P, Co¨B and Co¨P¨B alloys. Metal compounds, i.e., metal salts including the metal as an ion and not having a valence of 0, bound to another ion, usually an anion, e.g., CuO, CuC12, CuSO4 and the like are not considered a metallic material within the context of this invention.
As used herein, the terms "metal-coated article", "laminate article" and "metal-clad article" mean items which contain at least one substrate material and at least one metallic layer or patch comprising the biocidal metallic layer in intimate contact covering at least part of the surface of said substrate material. In addition, one or more intermediate structures, such as metalizing layers and polymer layers including, but not limited to adhesive layers and indicator layers can be employed between said metallic layer or patch and said substrate material.
As used herein, the term "metallic coating" or "metallic layer" means a metallic deposit/layer comprising one or more biocidal metallic layers applied to part of or the entire exposed surface of a temporary or permanent substrate. The metallic coating is intended to adhere to the surface of the permanent substrate to provide mechanical

- 15 -strength, wear resistance, corrosion resistance, anti-microbial properties and a low coefficient of friction.
As used herein, the term "metal matrix composite" (MMC) is defined as particulate matter embedded in a fine-grained and/or amorphous metal matrix.
MMCs are produced by suspending particles in a suitable plating bath and incorporating particulate nuttier into the deposit by inclusion.
As used herein, the term "fine-grained" or "grain-refined" refers to a polycrystalline metal or alloy having an average grain size that ranges from 2nm to 300nm (0.3 micron).
As used herein, the term "coating thickness" or "layer thickness" refers to depth in a deposit direction.
As used herein, the term "surface" means a surface located on a particular side of an article. A side of an article may include various surfaces or surface areas, including, but not limited to, a metallic article surface area, a polymer article surface area, a fastener surface area, a seam or joint surface area, etc. Thus, when indicating a coating is applied to a "surface" of an article, it is intended that such surface can comprise any one or all of the surfaces or surface areas located on that particular side of the article being coated.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to better illustrate the present disclosure by way of examples, descriptions are provided for suitable embodiments of the method/process/apparatus according to the present disclosure in which:
FIG. 1 illustrates an exemplary embodiment of a metallic antimicrobial composition comprising copper contained in a leg band for livestock and the entire leg band showing the outer absorbing fabric with a buckle.

- 16 -DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
The present invention focuses on articles that exhibit a highly desirable combination of antimicrobial, antibacterial, anti-fungal and/or anti-viral efficacy and enhanced mechanical durability. The inventive process renders the material functionally biocidal and highly resistant to abrasive and/or sliding wear, scuffing and scratching and the resulting articles suitable for use on livestock.
This invention relates to articles comprising grain-refined and/or amorphous, biocidal, metallic materials produced, e.g., by electrodeposition, which exhibit anti-microbial, antibacterial, anti-fungal and/or anti-viral behavior for extended periods of time while exhibiting enhanced mechanical durability.
Without wishing to be bound by theory, it is one aspect of the present invention that the metallic polycrystalline material exhibit bulk ionic dissolution characteristics that are commensurate with antimicrobial efficacy. This characteristic of a metallic material is related to the stored internal energy of its microstructure. Specifically, the arrangement of the constituent metallic atoms must be sufficiently disordered such that the bulk microstructure is prone to release of its constituent metal in antimicrobial concentrations from the outer surface of interest of the component from which the metallic material has been made or onto which the metallic material has been coated. This property is intrinsic to a material that possesses a high energy microstructure. As an example, cold working (e.g. rolling) of a fully annealed metal is a common method to increase the concentration of structural defects, in this case dislocations, throughout the microstructure of the metal.
The presence of these defects, in turn, increases the stored internal energy of the cold worked metal relative to the same material in the fully annealed, equilibrium state.
Another means to increase the internal stored energy of a metal is to refine the size of its constituent crystals or grains. Atoms located at the grain boundary and triple junction (intersection of three grain boundaries) regions are well-known to possess much higher stored energy values compared to those atoms situated within the well-ordered crystal

- 17 -lattice by virtue of being situated at the relatively disordered grain boundary/triple junction sites. The average grain size of a typical polycrystalline metallic material is on the order of 1 ¨ 100 microns in diameter. Under these normal circumstances, the proportion of atoms located at either grain boundaries or triple junctions is insignificant relative to the number situated at intragranular lattice positions and so the internal energy of the bulk material is not affected by the higher energy interfacial atoms.
However, when the grain size of the material is decreased, the volume fraction of the material's constituent atoms that are located at intercrystalline sites rises proportionately and, at an average grain size below approximately 300nm, the stored internal energy contribution of the interfacial atoms becomes discernible. This manifests itself in a tendency for the fine-grained metallic material to exhibit an enhanced ionic dissolution rate relative to its chemically equivalent coarse-grained counterpart.
Furthermore, because the fine-grained structure is not merely a surface phenomenon and exists throughout the entire mass of the metallic material, the ionic dissolution is not rendered inactive as readily as metal-based ointments, colloids, or creams. Hence, grain refinement is an effective means to promote the sustained dissolution of metallic material at concentrations that result in enhanced antimicrobial efficacy.
Articles or coatings according to the invention can be formed by electrodeposition or electroless deposition of suitable metallic compositions onto permanent or temporary substrates. Suitable permanent substrates include a variety of metal substrates, carbon-based materials selected from the group of graphite, graphite fibers and carbon nanotubes, and polymer substrates, commonly referred to as "plastics". If required, substrates can be metallized to render them sufficiently conductive for plating.
The person skilled in the art of plating, in conjunction with, e.g., U.S. Pat.
No.
5,352,266 (1994), U.S. Pat. No. 5,433,797 (1995), PCT/EP02/07023 (2002) and DE

10,108,893 (2002), will know how to electroplate or electroform selected fine-grained metals or alloys by selecting suitable plating bath formulations and plating conditions. As

- 18 -noted above, optionally solid particles can be suspended in the electrolyte and are consequently included in the deposit as described in PCT/EP02/07023 (2002).
In addition to improving antimicrobial efficacy, grain size reduction/grain refinement is known to increase the hardness, strength, abrasive wear, scuff, and scratch wear resistance of fully-dense metallic materials. Depending on the mechanical properties desired the grain size is suitably reduced to a level required to achieve the desired hardness, strength, abrasive wear, scuff, and/or scratch resistance.
In another embodiment of the invention grain-refined and/or amorphous metallic layer comprise metal flakes, powders and the like, processed into coherent "metallic bands" by using, e.g., an organic binder. Metallic bands typically contain between 1-20%
per weight of one or more organic binders. Suitable binders include, but are not limited to, epoxies, polyvinyl alcohol, poly-methylmethacrylate such as plexiglass and Lucite , polycarbonate, paraffin and hotmelt adhesives such as compositions comprising polyolefin, acrylate, and acetate.
In one embodiment the article is a leg band for livestock comprising a metal strip encapsulated in an absorber and a locking system. The locking system can be Velcro , a buckle, an adjustable ratchet locking system or any other fastening means which securely attach the leg band to the animal and can conveniently be removed.
In one embodiment, the novel article exhibits the biocidal and durability improvements disclosed herein either throughout the entire bulk of the metallic material microstructure or as a discrete coating on a suitable substrate. It is to be understood that the metallic material can be homogenous, or heterogeneous, e.g., graded and/or layered.
In one embodiment the metallic material is a Cu-Co laminate produced from a single electrolyte by modulating the deposition conditions as described, e.g., in U.S. Pat.
No. 9,005,420 (2015), assigned to the same applicant. A suitable sublayer thickness is in the range of 1 Onm-10 microns and the Co content provides for added strength in addition to exhibiting biocidal properties.

- 19 -In another embodiment the metallic material can also coat the inner and/or outer surface of the component or cover a portion of the inner and/or outer surface of the component only. To control the dissolution of the biocidal active material in the bio-fluid an electropositive or electronegative material can be applied to or incorporated into the biocidal metallic material. As an example, carbon/graphite "dots" can be applied on the biocidal metal to create galvanic couples accelerating copper metal dissolution thereby expanding the "zone of inhibition". Alternatively, zinc can be applied to galvanically protect Cu thereby slowing down the dissolution of Cu and the release of Cu ions and preferentially dissolving also providing some, albeit, lesser biocidal properties than Cu ions of similar concentration.
In one embodiment the release of biocidal active metal ions into the bio-fluid is controlled by the outer surface of the metallic material. For instance, Cu bands 1-10cm in width, preferably 2-10cm in width with a length of 1-50cm, preferably 5-25cm in length provide an adequate outer surface when used as leg band on livestock.
Perforations 0.1-5cm in diameter, preferably 0.5-3cm in diameter, can be incorporated into the metallic strip. Perforations can be used to, e.g., stich the metal strip to the absorbent material, and to hold gelling and/or wetting agents.
Biocidally Active Metallic Material:
Composition: One or more metallic materials which can be dissolved in the bio-fluid such as Co, Cu, Fe, Sn, Zn Alloying additions: B, P, C, Mo, S, W
Particulate additions: metals (Al, Cu, Sn, and Zn), their chlorides, sulfates, oxides or nitrides; carbon (carbon nanotubes, diamond, graphite, graphite dots, graphite fibers, graphene) 0. 1. 5. 10 Minimum particulate material fraction [% by "

- 20 -volume]:
Maximum particulate material fraction [% by 25. 50. 75 volume]:
Microstructure: Amorphous or crystalline Minimum average grain size [nm]: 2; 5; 10 Maximum average grain size [gm]: 0.1; 0.5; 1; 5; 10 Minimum Metallic Layer Thickness [gm]: 1; 5; 10; 25; 30; 50 Maximum Metallic Layer Thickness [mm]: 0.1; 1; 2.5 Minimum hardness of the electrodeposit [VHN]: 50; 100; 150; 200 Maximum hardness of the electrodeposit [VHN]: 600, 800; 1200 Minimum Porosity [%]: 0; 1; 5; 10 Maximum Porosity [%]: 52; 50; 75; 95 Metallic Material Substrate:
At times suitable substrates can be employed to serve as carrier for the antimicrobial metallic material(s) and/or to incorporate indicator materials or gelling agents. They include metallic materials which are inert and do not dissolve in the bio-fluid. Suitable substrates can also include non-metallic materials such as organic polymers. Suitable substrate geometries include open cell foams, meshes, perforated plates and the like which provide a relative unimpeded fluid flow. The metallic material layer(s) can be applied to one side or both sides of the substrates and the metallic material to layers can be applied to encapsulate the entire substrate.
In one preferred embodiment the substrate comprises a metallic material and is selected so it can simultaneously serve as the end of life indicator. Examples of metallic substrates which can also provide an indicator function include, but are not limited to, Al and Zn. Upon exhaustion of, e.g., the Cu biocidal layer which encapsulates such substrates and exposure of the Al and/or Zn substrate, "white rust", i.e., Al and/or Zn

-21 -chloride, hydroxide will become visible and the outer absorber layer of the legband will gradually turn white or "white patches" will become visible.
Absorbent Material:
In one preferred embodiment the invention incorporates an absorbent material to provide a convenient, preventive antibacterial medical device for animals capable of managing/regulating the moisture content in the device and thereby influencing and preferably controlling the formations and/or release of the biocidal active compound(s).
In one preferred embodiment the present invention provides a convenient, preventive antibacterial medical device for animals comprising (i) a composition capable of slowly generating and/or releasing antibacterially active compounds, (ii) a moisture absorbing material in intimate contact with the antibacterial composition, and (iii) means for attaching the medical device to the outer body of animals ensuring that the generated and/or released antibacterially active compounds contacts and suitable treats the skin and/or hooves/claws of animals wearing such a device. Preferably, durable, moisture absorbing materials are used to cover or encapsulate the active metal band including woven and unwoven fabrics to prevent the metal from exposure to dirt and to prevent sharp metal edges from harming the animal by abrasion, inflicting cuts, etc.
The moisture absorbing materials can be natural (animal or plant) based or synthetic materials. Suitable absorbing textiles include polyamides including Nylon , polyesters, polyolefins, aramids including Kevlar , and acrylics.
In one preferred embodiment the invention the leg band contains a fluid absorbing material in the range of between I% and 50% by weight of the leg band.
Preferably, the absorber is capable of absorbing at least 5% of its own dry weight of fluids such as water, bio fluids and synthetic urine.
Complexing Agents:

- 22 -In one preferred embodiment complexing agents are added to prevent the formation of metal hydroxide which can precipitate if the bio-fluid is alkaline (pH>7).
Complexing agents include, but are not limited to glycine, tartrate, pyrophosphate, fluoborate, ammonium salts, glycerol, ethylenediamine, ethylendiaminetetraacetate (EDTA). The person skilled in the art will appreciate that the potential toxicity of these compounds as well as their degradation products needs to be considered. For instance, EDTA which is a chelating agent widely used in industry and agriculture, is fairly resistant to chemical and biological degradation and its use may give cause to ecological concerns.
In one preferred embodiment the invention incorporates at least one complexing agent in the range of between 1% and 50% by weight of the leg band.
Gelling Agent:
In another embodiment, the invention utilizes gelling agents to prevent the excessive release or "wash out" of antibacterially active compounds in case of very wet conditions resulting in excess fluids contacting the antimicrobial material(s). Suitable gelling agents include acacia, alginic acid, bentonite, Carbopols (also known as carbomers), various cellulose materials (methylcellulose, carboxymethyl cellulose, ethylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose), gelatin, starches, various silicates, e.g., magnesium aluminum silicate polyvinyl alcohol, sodium alginate, tragacanth, and xanthan gum.
It is known that some gelling agents require a "neutralizer" or a pH adjusting chemical. Carbomers, which is a generic name for a family of polymers used as gelling agents known as Carbopol , are dry powders having high bulk densities and forming acidic aqueous solutions (pH around 3.0). They thicken at higher pHs (around 5 or 6) and also swell in aqueous solution to as much as 1000 times their original volume.
Their solutions range in viscosity from 0 to 80,000 centipoise (cps).

- 23 -In one embodiment, the moisture absorbing material is impregnated with the gelling agent while in another embodiment the metallic material is partially or totally coated with the gelling agent with or without the use of a binder.
The gelling agent is selected to increase the viscosity of water and/or the bio fluid at room temperature by at least 10%, preferably by at least 25%, and more preferably by at least 50%.
End of Life/Replacement Indicator:
In another embodiment an indicator or die material conveniently signifying the depletion of the biocidal active metallic material can be incorporated into the metallic material as well, e.g. in the center of the strip, band or wire, and gets released once the biocidally active material is at or nearing depletion to signify the need to exchange the device. Once the metallic material is used up to the extent that the indicator material gets exposed to bio-fluid, the indicator material reacts and/or dissolves in the bio-fluid and results in, e.g., a color change which is easily detectable. One or more suitable indicator materials can be used to change the color of the article, indicators reacting with moisture to change color such as pH indictors, e.g., phenolphthalein if the fluid is alkaline (purple above pH 9), Malachite green, green in (pH range of 2-12), methylorange in case the fluid is acidic (red below pH3), urine indicators, ammonia indicators or the like.
As indicated above, in a preferred embodiment the indicator material is incorporated into the metallic material substrate, or comprises the metallic material substrate.
Articles or coatings made according to the process of this invention find use in a variety of applications requiring improved durability with respect to wear and tear and enhanced antimicrobial, antibacterial, anti-fungal and/or anti-viral efficacy.
Specific application areas include the legs and feet of animals.

- 24 -FIG. 1 shows an exemplary embodiment of a leg band for livestock, specifically the antimicrobial copper foil on top of the assembled leg band showing the outer absorbing fabric with a buckle for fastening the device to the leg of an animal.
VARIATIONS
The foregoing description of the invention has been presented describing certain operable and preferred embodiments. It is not intended that the invention should be so limited since variations and modifications thereof will be obvious to those skilled in the art, all of which are within the spirit and scope of the invention.

Claims (20)

Anti-Bacterial Leg Bands for the Prevention of Footrot, Interdigital Dermatitis and Other Bacterial Infections in Livestock

1. A flexible and removable device for fastening to the leg of an agricultural animal providing antimicrobial properties comprising:
an outer fabric material capable of absorbing at least 5% of its own dry weight of water;
(ii) a metallic antimicrobial composition comprising at least one metal chosen from the group consisting of Co, Cu, Sn and Zn having a grain-refined microstructure with an average grain size of less than 10 microns and/or an amorphous microstructure, said metallic antimicrobial composition being a strip with or without perforations which is 5-50cm long, 1-10cm wide, and has a thickness to provide antimicrobial properties for a period of at least 1 month;
(iii) an indicator material reacting with water and/or bio-fluid resulting in a visible color change to signify the depletion of said a metallic antimicrobial composition; and (iv) means for securing said device to an animal leg.

2. The metallic antimicrobial composition according to claim 1 which is substantially free of Ag, Ni, Cr, Pb, Sb and As.

3. The metallic antimicrobial composition according to claim 1, wherein at least part of said metallic antimicrobial composition is compositionally graded or layered.

4. The a metallic antimicrobial composition according to claim 1, wherein at least part of said metallic antimicrobial composition is grain refined comprising an average grain size between 2 nm and 300 nm.

5. The metallic antimicrobial composition according to claim 1, wherein at least part of said metallic antimicrobial composition is amorphous.

6. The metallic antimicrobial composition according to claim 1, wherein said indicator material is embedded in said metallic antimicrobial composition.

7. The a metallic antimicrobial composition according to claim 1 having a porosity greater than or equal to 5%.

8. The a metallic antimicrobial composition according to claim 1 comprising at least one metallic material selected from the group consisting of rounds, flakes, chips, plates, powders held together by an organic binder.

9. A flexible article for application to the body of an animal to provide both fluid absorbency and antimicrobial activity comprising:
(i) a permanent substrate which is electrochemically inert and pervious to fluid, (ii) a consumable antimicrobial active metallic insert which is fluid pervious provided on the permanent substrate and having a thickness between 1 and 500 microns, the consumable, antimicrobial active metallic coating/layer comprising a consumable antimicrobial active metallic material capable of being dissolved in said fluid and forming metal ions; and (iii) an electrically non-conductive, fluid pervious absorber positioned on and in intimate contact with the consumable antimicrobial active metallic insert;
wherein the consumable antimicrobial active metallic insert provides antimicrobial properties for a period of at least 1 month.

10. The permanent substrate according to claim 9 which is a polymer foam.

11. The consumable antimicrobial active metallic insert according to claim 9 which is compositionally graded or layered.

12. The consumable antimicrobial active metallic insert according to claim 9 which is grain refined having an average grain size between 2 nm and 300 nm.

13. The consumable antimicrobial active metallic insert according to claim 9 which is amorphous.

14. The consumable antimicrobial active metallic insert according to claim 9 comprising at least one metallic material selected from the group consisting of rounds, flakes, chips, plates, powders held together by an organic binder.

15. The article according to claim 9, wherein an indicator is embedded in said consumable antimicrobial active metallic insert.

16. An absorbent composite structure suitable for use in disposable absorbent articles for use on livestock, said composite structure comprising:
(i) an absorber in the range of between 1% to 50% by weight of the composite structure, said absorber being capable of absorbing at least 5% of its own dry weight of water;
(ii) a metallic antimicrobial composition in the range of between 5% to 95%
by weight of the composite structure, said metallic antimicrobial composition comprising at least one metal chosen from the group consisting of Co, Cu, Sn and Zn having a grain-refined microstructure with an average grain size of less than 10 microns and/or an amorphous microstructure, and a hardness exceeding 100VHN, said metallic antimicrobial composition being a strip with or without perforations which is 5-50cm long, 1-10cm wide, and having a thickness to provide antimicrobial properties for a period of at least 1 month;
(iii) an indicator material composition in the range of between 0% to 1% by weight of the composite structure, said indicator material capable of reacting with at least one fluid selected from the group consisting of water, bio-fluid, and synthetic urine resulting in a visible color change to signify the depletion of said a metallic antimicrobial composition;
(iv) a gelling agent in the range of between 0% to 1% by weight of the composite structure, said gelling agent capable of reacting with at least one fluid selected from the group consisting of water, bio-fluid, and synthetic urine to increase the viscosity of said fluid by at least 10%;
(v) a complexing agent for metallic ions, released from said metallic antimicrobial composition, in the range of between 0% to 50% by weight of the composite structure; and (vi) means for securing said absorbent composite structure to an animal leg.

17. The metallic antimicrobial composition according to claim 16 which is substantially free of Ag, Ni, Cr, Pb, Sb and As.

18. The metallic antimicrobial composition according to claim 16, wherein at least part of said metallic antimicrobial composition is compositionally graded or layered.

19. The a metallic antimicrobial composition according to claim 16, wherein said indicator material is embedded in the metallic antimicrobial composition.

20. The a metallic antimicrobial composition according to claim 16, comprising at least one metallic material selected from the group consisting of rounds, flakes, chips, plates, powders held together by an organic binder.