DESC:FIELD OF INVENTION
[0001] The present disclosure relates to the field of anti-microbial compositions. In particular, the present disclosure provides an anti-microbial composition comprising a plurality of copper and silver nanoparticles, at least one quaternary ammonium compound and at least one silane.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The current era of mankind is witnessing a new war, one of survival, between humans and microbes. Every year brings with it new emerging viruses, most of them leaving mild flu like symptoms while some leading to major health concerns. Some of the viruses seen in recent years include, for example, Middle East Respiratory Syndrome coronavirus (MERS), Zika virus, Ebola virus, Human Immunodeficiency Virus (HIV), and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV 2). Bacteria are also known to cause a number of severe diseases like tuberculosis, urinary tract infection, syphilis and cholera. Apart from these, other pathogenic protozoa and fungi are also known. With the microbes multiplying at a steady rate and mutating to develop drug resistant genes, the fight with microbes is ever growing. Apart from directly contracting a pathogen from an infected person, we are also susceptible to indirect transfer via surfaces like door knobs, public transport, faucets, handles, railings, elevators etc. An infected person may transfer the pathogens to the surfaces they come in contact with, called fomites, which further transmit the pathogens to a new host. These fomites may have microbes living on them for hours or days. A conventional alcohol based spray lasts only up to 30 seconds. It becomes practically impossible to keep surfaces sanitized at all times using the same. There is a need for compositions with anti-microbial properties that can stop the spread of the infections from such fomites and decrease the lifecycle of microbes over longer durations of time.
[0004] The anti-microbial properties of metals like copper and silver have been known for centuries and may be utilized in these compositions. However, generating suitable compositions comprising them is challenging. Nanoparticles of silver and copper have also been explored as anti-microbials for surfaces but, they have many limitations. Primarily, compositions comprising these nanoparticles must be stabilized for long periods of time. Even if stabilized, the compositions must have enough adhesion which is not seen in compositions known in the art. To overcome this deficiency manufacturers have to add additional suitable adhesives based on the different substrate surfaces, to bind the composition to the surfaces. This adds to the overall production costs of the composition. Another problem associated with the anti-microbial metal compositions known in the art, is the gradual decay in anti-microbial efficiency with aging. Exposure of the metal nanoparticles to the environment leads to faster oxidation and thus, reduced efficacy. They show anti-microbial activity in the initial days of installation however these effects quickly fade away.
[0005] Therefore, there is a need in the art, to provide an anti-microbial composition comprising nanoparticles that overcomes the existing deficiencies in the art. The inventors of the present disclosure have arrived at an anti-microbial composition that has high efficacy, good adhesion and longevity.

OBJECTS OF THE INVENTION
[0006] An object of the present disclosure is to provide an anti-microbial composition that satisfies the existing needs, as well as emerging ones, and generally overcomes the deficiencies found in the prior art.
[0007] An object of the present disclosure is to provide an anti-microbial composition that is effective against a host of microbes.
[0008] An object of the present disclosure is to provide an anti-microbial composition that has contact killing activity.
[0009] An object of the present disclosure is to provide an anti-microbial composition that can be coated on surfaces to prevent secondary transmission of infections from surfaces.
[00010] An object of the present disclosure is to provide an anti-microbial composition that has reduced oxidation and thus, improved aging efficiency.
[00011] An object of the present disclosure is to provide an anti-microbial composition that forms covalent bonds with the substrate surface to improve adhesion.

SUMMARY OF THE INVENTION
[00012] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[00013] Aspects of the present disclosure provide a composition that has contact killing activity against a host of microbes and thereby acts as an effective anti-microbial.
[00014] In an aspect, the present disclosure relates to an anti-microbial composition comprising:
a) a plurality of copper and silver nanoparticles encapsulated by at least one silane; and
b) at least one quaternary ammonium compound encapsulated by at least one silane.
[00015] In an embodiment, the copper and silver nanoparticles may be encapsulated by the silane to form a nanosol gel.
[00016] In an embodiment, the nanoparticles may be formed from metallic copper, metallic silver, copper alloy, silver alloy, copper salts, silver salts, or combinations thereof. In some embodiments, the nanoparticles may be formed by reduction of the metallic copper, metallic silver, copper alloy, silver alloy, copper salts, silver salts, or combinations thereof.
[00017] In an embodiment, the quaternary ammonium compound may be selected from N-alkyl-N-benzyl-N-N-Dimethyl ammonium chloride, dialkyldimethylammonium chloride, benzethonium chloride, methylbenzethonium chloride or combinations thereof. In a preferred embodiment, the alkyl may be selected from a C8-C16 alkyl.
[00018] In an embodiment, the silane may be selected from alkylsilane, vinylsilane, methacryloxysilane, aminosilane, acryloxysilane, epoxysilane, or combinations thereof. In a preferred embodiment, the silane may be selected from acetoxysilane, glycidoxypropyl trimethoxysilyl silane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3 dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane hydrochloride or combinations thereof. The silane improves adhesion of the composition.
[00019] In an embodiment, the composition comprises the plurality of copper and silver nanoparticles in a weight percentage range of about 2% to about 10% by weight of the composition.
[00020] In an embodiment, the composition comprises the quaternary ammonium compound in a weight percentage range of about 3% to about 15% by weight of the composition.
[00021] In an embodiment, the composition comprises the silane in a weight percentage range of about 2% to about 8% by weight of the composition.
[00022] In an embodiment, the anti-microbial composition may further comprise a solvent. The solvent may be selected from water, de-mineralized water, alcohol, emulsions, paints, or varnishes.
[00023] In an embodiment, the anti-microbial composition is an active contact killing composition.
[00024] In a preferred embodiment, the anti-microbial composition may be an anti-microbial coating composition that is coated on a substrate surface to form a protective layer. Microbes coming in contact with the surface coated with the composition are rapidly destroyed thus keeping the substrate surface effectively self-sanitized.
[00025] In an embodiment, the anti-microbial composition can be used for coating multiple surfaces, including doors, tableware, walls, counter tops, elevators, escalator rails, handles, among others.
[00026] In yet another aspect, the present disclosure provides a process of preparing an anti-microbial composition comprising the steps of:
a) preparing an aqueous solution of a plurality of copper and silver nanoparticles;
b) adding the aqueous solution of step a) to at least one silane with stirring to give a solution A;
c) preparing an aqueous solution of at least one quaternary ammonium compound;
d) adding and mixing the aqueous solution of step c) to the at least one silane to obtain a solution B; and
e) grafting the solution A and solution B on a solvent to give the composition.
[00027] In an embodiment, the solution A may be a nanosol gel.
[00028] In an embodiment, the composition obtained may further be homogenized. The solvent may be selected from water, de-mineralized water, alcohol, emulsions, paints, or varnishes.
[00029] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[00030] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[00031] Figure 1 illustrates the active contact killing activity of the anti-microbial composition as per an embodiment of the present disclosure.
[00032] Figure 2 provides an illustrative process flow of anti-microbial action on pathogens of the anti-microbial composition as per an embodiment of the present disclosure.
[00033] Figure 3 provides the X-ray diffraction pattern obtained for the plurality of nanoparticles prepared as per an embodiment of the present disclosure.
[00034] Figure 4 provides a line graph for the anti-microbial performance of compositions comprising varying amounts of copper and silver nanoparticles.

DETAILED DESCRIPTION OF THE INVENTION
[00035] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[00036] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[00037] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[00038] In some embodiments, numbers have been used for quantifying weights, percentages, concentrations, ratios and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[00039] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[00040] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00041] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[00042] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[00043] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00044] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[00045] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[00046] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as composition or process. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[00047] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[00048] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[00049] The term ‘anti-microbially effective amount’ as used herein refers to the amount of the composition that is sufficient to inhibit or stop the microbe’s growth. This amount would vary depending on the genus and species of the microbe, the components of the composition, or the weight percentages of the components.
[00050] As used herein, the term ‘substrate surface’ refers to the outer exposed face of the substrate that comes in contact with pathogens or microbes.
[00051] The term ‘grafting’ as used herein refers to the process of hooking or covalent bonding of a component onto to the solvent, additive or base employed. The covalent bond maintains stability and adherence of the composition.
[00052] The terms ‘microbe’ and ‘pathogen’ may be interchangeably used in the present disclosure.
[00053] In an embodiment, the present disclosure provides an anti-microbial composition comprising:
a) a plurality of copper and silver nanoparticles encapsulated by at least one silane; and
b) at least one quaternary ammonium compound encapsulated by at least one silane.
[00054] In an embodiment, the copper and silver nanoparticles comprise copper nanoparticles and silver nanoparticles. In some embodiments, these nanoparticles may be prepared simultaneously. In some embodiments, these nanoparticles may be prepared separately and then mixed. The nanoparticles prepared are generally spherical and uniform in size.
[00055] In an embodiment, the copper and silver nanoparticles may be encapsulated by the silane to form a nanosol gel.
[00056] In an embodiment, the composition comprises the plurality of copper and silver nanoparticles in a weight percentage range of about 2% to about 10% by weight of the composition. In a preferred embodiment, the nanoparticles may be present in a weight percentage range of about 2% to about 6% by weight of the composition.
[00057] In an embodiment, the copper nanoparticles and silver nanoparticles may be present in a ratio of about 20:1 to about 13:1, preferably the copper nanoparticles and silver nanoparticles may be present in a ratio of about 15:1.
[00058] In an embodiment, the average size of the copper and silver nanoparticles may be 10 nm to 90 nm. In a preferred embodiment, the average size of the copper and silver nanoparticles may be 35 nm to 70 nm.
[00059] In an embodiment, the copper nanoparticles may be produced by reduction of metallic copper, copper salts, copper alloy, or combinations thereof. In an embodiment, the copper salts may include copper iodide, copper sulfate, copper bromide, copper chloride, copper oxide, copper acetate or combinations thereof. In a preferred embodiment, the reduction of copper ions to copper nanoparticles may be catalyzed by sodium hydroxide and reducing agent may be ascorbic acid.
[00060] In an embodiment, the silver nanoparticles may be produced by reduction of metallic silver, silver salts, silver alloy, or combinations thereof. In an embodiment, the silver salts may include silver iodide, silver bromide, silver nitrate, silver chloride, silver oxide, or combinations thereof. In a preferred embodiment, the reduction of silver ions to silver nanoparticles may be catalyzed by sodium hydrosulphide and reducing agent may be polyvinylpyrrolidone.
[00061] In an embodiment, the quaternary ammonium compound may be selected from N-alkyl-N-benzyl-N-N-Dimethyl ammonium chloride, dialkyldimethylammonium chloride, benzethonium chloride, methylbenzethonium chloride or combinations thereof. In a preferred embodiment, the alkyl may be selected from a C8-C16 alkyl.
[00062] In some preferred embodiments, the quaternary ammonium compound may be N-alkyl-N-benzyl-N-N-Dimethyl ammonium chloride, wherein alkyl is C12-C16-alkyl. In some preferred embodiments, the quaternary ammonium compound may be dialkyldimethylammonium chloride, wherein alkyl is C8-C10-alkyl.
[00063] In an embodiment, the quaternary ammonium compound may be present in a weight percentage range of about 3% to about 15% by weight of the composition.
[00064] In an embodiment, the silane may be selected from alkylsilane, vinylsilane, methacryloxysilane, aminosilane, acryloxysilane, epoxysilane, or combinations thereof. In a preferred embodiment, the silane may be selected from acetoxysilane, glycidoxypropyl trimethoxysilyl silane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3 dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane hydrochloride or combinations thereof.
[00065] In an embodiment, the silane may be present in a weight percentage range of about 2% to about 8% by weight of the composition.
[00066] Without being bound to theory, it is believed that the silane aids the composition in forming covalent bonds with the substrate surface on which it may be coated so as to improve the adhesion to these surfaces thereby keeping the composition intact for longer periods of time. Further, the nanoparticles are metals which when exposed to environment are bound to undergo oxidation, but the encapsulation by the silane, a coupling agent, limits the exposure of the nanoparticles to oxygen, so that the process of oxidation takes longer and thus the anti-microbial efficacy remains for prolonged periods of time.
[00067] In an embodiment, the anti-microbial composition may further comprise a solvent. The solvent may be selected from water, de-mineralized water, alcohol, isopropyl alcohol, emulsions, paints, or varnishes. The solvent provides a base for the anti-microbial composition. However, it is understood that any other solvent well-known to a person of skill in the art may be employed that does not go beyond the scope and spirit of the present disclosure.
[00068] In an embodiment, the anti-microbial composition is an active contact killing composition, which means, the microbes are immediately killed on coming in contact with the composition. Without being bound by theory, it is believed that the composition releases copper and silver ions that blast through outer membranes of the microbe and efficiently attack and degrade the DNA and/or RNA of the pathogens that come in contact. Once the genome of the pathogen is destroyed they fail to mutate or develop resistance. This overcomes the drawbacks of known anti-microbial compositions to which the microbes eventually develop resistance and mutate. Figure 1 illustrates the active contact killing activity of the anti-microbial composition as per an embodiment of the present disclosure.
[00069] In a preferred embodiment, the anti-microbial composition may be an anti-microbial coating composition that is coated on a substrate surface in one or a plurality of layers to form a protective layer. Microbes coming in contact with the surface coated with the composition are rapidly destroyed thus keeping the substrate surface effectively self-sanitized.
[00070] In an embodiment, the coating of the substrate surface may be performed by imparting a thin protective layer of the composition on the surface. In an embodiment, the coating of the substrate surface may be performed by spraying, treating, buffing, painting, dipping, drying or combinations thereof, until the desired area of the surface is covered.
[00071] In an embodiment, the composition may be coated till an anti-microbially effective amount is present in the protective layer.
[00072] Figure 2 provides an illustrative process flow of anti-microbial action, on pathogens, of the anti-microbial composition as per an embodiment of the present disclosure. Figure 2 (a) shows the anti-microbial composition comprising nanoparticles as an anti-microbial coating composition that is coated on a substrate surface. Figure 2(b) shows a microbe approaching the surface; Figure 2(c) shows the copper/silver nanoparticles from the composition attacking the microbe by penetrating the cell wall of the microbe; Figure 2(d) show the metals rupturing the cell wall and destroying the DNA/RNA to prevent any mutation or replication; and Figure 2(e) shows the anti-microbial composition eventually killing all microbes coming in contact with the substrate surface.
[00073] In an embodiment, the composition is effective against a host of microbes including viruses, bacteria, fungi, protozoa, spores, molds or combinations thereof.
[00074] In an embodiment, the composition is effective against a host of microbes including, but not limited to, SARS-CoV2, Bacteriophage MS2, Shigella, Escherichia spp. (E. Coli), Salmonella spp., Mycobacterium tuberculosis, MRSA, influenza virus, H3N2, Enterobacteriaceae, Pseudomonas spp., Staphylococci spp., Acinetobacter spp., or Citrobacter spp..
[00075] In a preferred embodiment, the composition is effective against microbes causing urinary tract infection.
[00076] In an embodiment, the composition is an effective anti-microbial, anti-viral, anti-fungal, anti-bacterial, or combinations thereof. In a preferred embodiment, the composition may demonstrate anti-viral efficacy of over 99.96%.
[00077] In an embodiment, the composition has superior stability and synergistic activity.
[00078] In an embodiment, the anti-microbial composition has improved longevity. In some embodiments, when the composition is mixed with paints or varnishes the composition may be effective for up to 365 days. In other embodiments, the composition may be effective for up to 120 days. In other embodiments, the composition may be effective for up to 90 days. In some embodiments, the composition may be effective for up to 60 days. Over a course of time, most compositions lose their anti-microbial efficacy. However, the anti-microbial composition of the present disclosure keeps its efficacy intact over longer periods of time increasing its aging efficacy. The efficacy is maintained for long durations due to the silane envelope formed around the components.
[00079] In an embodiment, the anti-microbial composition is capable of maintaining clean and safe environments.
[00080] In some embodiments, the composition may be water and moisture repellant. In an embodiment, the composition is environmentally safe and does not use bleaches or acids which in conventional formulations can get washed away into water bodies and distort marine life.
[00081] In an embodiment, the anti-microbial composition may be used for coating porous or non-porous substrate surfaces.
[00082] In an embodiment, the anti-microbial composition may be used for coating substrate surfaces including surfaces of doors/drawer knobs, handles, tables, tableware, poles, counter tops, elevators, hand rails, escalator rails, walls, food packages, seating, sports equipment, gym equipment, shopping carts, medical devices, toys, steering wheels, switches, faucets, fabrics, containers, cleaning cloth, toilet seats, automobile parts, in biotechnological or chemical manufacturing, or pipes. The composition may be employed in public spaces including, health care settings, work place, parks, schools, gyms, offices, hotels, malls, shopping centers, restaurants, airports, bus stations, museums, storage facilities, railways, taxis, bathrooms, metro-rails, and other transport means, that have substrate surfaces frequently coming in contact with people and are likely to transfer infections through pathogens. It may be coated on substrate surfaces of different materials, including, glass, metal, polymer, alloy, ceramic, plastic, fabric, wood, concrete and fabrics.
[00083] In an embodiment, the anti-microbial composition is durable and when coated on a substrate surface also prevents any staining of the substrate surface. Said composition is skin friendly and does not harm skin coming in contact with the substrate surface.
[00084] In an embodiment, the anti-microbial composition advantageously shows improved adhesion to the substrate surface. The improved adhesion keeps the coating intact for longer time. In an embodiment, the anti-microbial composition may show adhesion for up to 180 days if not mechanically damaged.
[00085] In an embodiment, the composition may be mixed with other anti-microbial agents.
[00086] In an embodiment, the present disclosure relates to an anti-microbial formulation comprising:
a) a plurality of copper and silver nanoparticles encapsulated by at least one silane;
b) at least one quaternary ammonium compound encapsulated by at least one silane; and
c) an additive.
[00087] In an embodiment, the additive may be selected from corrosion inhibitors, emulsifiers, colorants, disinfectants, modifying agents, carrier, solvent, polishing agents, fragrances, surfactant, or combinations thereof. However, a person skilled in the art would appreciate that any other additive(s) can be utilized to serve the intended purpose without departing from the scope and spirit of the invention.
[00088] In an embodiment, the additives may be selected from miscible organic solvents including, isopropyl alcohol, polyvinyl alcohol, methyl alcohol, ethyl alcohol, DMF, DMSO, chloroform, acetone, methyl ethyl ketone, or combinations thereof; aqueous solvents including water, de-mineralised water, distilled water or combinations thereof; acrylates including methyl methacrylate, methyl acrylate, butyl acrylate, acrylic acid, 2-ethylhexyl acrylate or combinations thereof; polysorbates; polyurethanes; polyamides, or combinations thereof. However, a person skilled in the art would appreciate that any other additive(s) can be utilized to serve the intended purpose without departing from the scope and spirit of the invention.
[00089] In an embodiment, the formulation may be in the form of a paste, hydrogel, emulsion, aerosol, suspension, solution, dispersion, solid, polymer, semi-solid, or wax.
[00090] In an embodiment, the anti-microbial formulation may be transparent that when coated or applied on a substrate surface makes it microbe-free. Consequently, these surfaces stop the spread of infection via secondary transmission of microbes.
[00091] In another embodiment, the present disclosure further provides a process of preparing an anti-microbial composition comprising: a plurality of copper and silver nanoparticles, at least one quaternary ammonium chloride and at least one silane.
[00092] In an embodiment, the present disclosure provides a process of preparing an anti-microbial composition comprising the steps of:
a) preparing an aqueous solution of a plurality of copper and silver nanoparticles;
b) adding the aqueous solution of step a) to at least one silane with stirring to give a solution A;
c) preparing an aqueous solution of at least one quaternary ammonium compound;
d) adding and mixing the aqueous solution of step c) to at least one silane to obtain a solution B; and
e) grafting the solution A and solution B on a solvent to give the composition.
[00093] In an embodiment, the process is an exothermic process.
[00094] In an embodiment, the copper nanoparticles may be produced by reduction of metallic copper, copper salts, copper alloy, or combinations thereof. In an embodiment, the copper salts may include copper iodide, copper sulfate, copper bromide, copper chloride, copper oxide, copper acetate or combinations thereof.
[00095] In a preferred embodiment, the reduction of copper ions to copper nanoparticles may be catalyzed by sodium hydroxide and reducing agent may be ascorbic acid.
[00096] In a preferred embodiment, the reduction may be performed by adding ascorbic acid to the copper sulfate and stirring at room temperature, or at 35°C for about 30 minutes. This may be followed by adding catalyst sodium hydroxide and stirring at about 80°C for about 120 minutes to give aqueous copper nanoparticles, wherein copper nanoparticles are suspended in water.
[00097] In an embodiment, the silver nanoparticles may be produced by reduction of metallic silver, silver salts, silver alloy, or combinations thereof. In an embodiment, the silver salts may include silver iodide, silver bromide, silver chloride, silver nitrate, silver oxide, or combinations thereof.
[00098] In a preferred embodiment, the reduction of silver ions to silver nanoparticles may be catalyzed by sodium hydrosulphide and reducing agent may be polyvinylpyrrolidone.
[00099] In a preferred embodiment, the reduction may be performed by adding polyvinylpyrrolidone to silver nitrate and stirring at room temperature, or at 35°C for about 40 minutes. This may be followed by adding catalyst sodium hydrosulphide and stirring at about 35°C for about 60 minutes to give aqueous silver nanoparticles, wherein silver nanoparticles are suspended in water.
[000100] In an embodiment, the aqueous solution of the plurality of copper and silver nanoparticles is prepared by adding the aqueous copper nanoparticles in the aqueous silver nanoparticles and stirring. In an embodiment, the copper nanoparticles and silver nanoparticles may be present in a ratio of about 20:1 to about 13:1, preferably the copper nanoparticles and silver nanoparticles may be present in a ratio of about 15:1.
[000101] This aqueous solution of the plurality of copper and silver nanoparticles is then added to the silane, preferably in a ratio of about 1:1. This addition may be performed with constant stirring at about 45 rpm for about 120 minutes. Subsequent to the addition, the solution may be stabilized for about 20 minutes to about 40 minutes to give the solution A. In an embodiment, the solution A may be a nanosol gel.
[000102] In an embodiment, the aqueous solution B is prepared by adding the at least one quaternary ammonium compound to the at least one silane, preferably in a ratio of 1:1.This addition is performed by constant stirring at about 45 rpm for about 30 minutes. Subsequent to the addition, the solution may be stabilized for about 20 minutes to about 40 minutes to give the solution B.
[000103] In an embodiment, mixing of the aqueous solution A and the aqueous solution B may be performed slowly, preferably drop-wise, for about 20 minutes to about 40 minutes to obtain a homogenous solution. The mixing may preferably be performed at a temperature of about 65°C.
[000104] In an embodiment, the composition obtained may further be homogenized. The solvent may be selected from water, de-mineralized water, alcohol, emulsions, paints, or varnishes.
[000105] In an embodiment, the present disclosure provides a method of inhibiting growth of or killing of microbes on a substrate surface comprising coating the anti-microbial composition on the substrate surface in an anti-microbially effective amount.
[000106] In yet another embodiment, the present disclosure relates to a manufacturing product or device coated with the anti-microbial composition.
[000107] In an embodiment, the composition of the present disclosure may also be used in combination with other known anti-microbial materials or compositions.
[000108] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

EXAMPLES
[000109] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.
[000110] MATERIALS: All the chemicals for the purposes of the examples in the present disclosure were obtained from third-party suppliers, including, Merck India, and Sigma-aldrich Chemical Pvt. Ltd, Kolkata. The ATP assessment meter was sourced from Hygiena LLC, USA.
[000111] Example 1: Preparation of anti-microbial composition
[000112] Copper sulfate (40 mg) was taken and reduced to copper nanoparticles using ascorbic acid as reducing agent (25% of copper sulfate) and stirred for about 30 minutes at 35 degree Celsius. This was followed by addition of sodium hydroxide as the catalyst (0.2% of ascorbic acid) and stirring for about 2 hours at 80 degree Celsius to give copper nanoparticles (8 mg/mL) suspended in water. Similarly, silver nitrate (20 mg) was taken and reduced to silver nanoparticles using PVP as reducing agent (25% of silver nitrate) and stirring for about 40 minutes at 35 degree Celsius. This was followed by addition of sodium hydrosulphide as the catalyst (0.2% of PVP) and stirring for about 1 hour at 35 degree Celsius to give silver nanoparticles (0.95 mg/mL) suspended in water.
[000113] These nanoparticles were then converted into a mixture of copper and silver nanoparticles (8.95 mg/mL) by drop-wise addition of the copper nanoparticles into the silver nanoparticles in a molar feed ratio of 15:1. The solution was stirred for about 30 minutes. Figure 3 provides the X-ray diffraction pattern for the prepared plurality of copper and silver nanoparticles.
[000114] The obtained nanoparticles were then grafted with glycidoxy propyl trimethoxysilyl silane (10 gms) to give copper and silver nanoparticles encapsulated by silane producing a nanosol - Solution A. This grafting was performed by adding drop-wise the nanoparticles into the silane with continuous stirring for 120 minutes at 45 rpm. This was followed by stability mixing for another 30 minutes to give the copper and silver nanoparticles encapsulated by silane nanosol gel.
[000115] 5% by weight in the ratio 1:1 of N-alkyl-N-benzyl-N-N-dimethyl ammonium chloride (10 mg) was grafted with glycidoxy propyl trimethoxysilyl silane (10 mg) to give the quaternary ammonium compound encapsulated by silane - Solution B. Solution A and Solution B were mixed together drop-wise for 30-40 minutes at 65 degree Celsius to give the anti-microbial composition.
[000116] Example 2: Anti-microbial compositions with varying Cu:Ag ratios
[000117] Multiple anti-microbial compositions were prepared with varying molar feed ratios of copper and silver nanoparticles. Rest of the process was the same as in Example 1. These compositions were then compared for their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). MIC is the lowest concentration of an antimicrobial ingredient or agent that is bacteriostatic (prevents the visible growth of bacteria) and MBC is the lowest concentration of an antibacterial agent required to kill a bacterium over a fixed, somewhat extended period, such as 18 hours or 24 hours, under a specific set of conditions. Table No. 1 below provides the results.
Table No. 1: Compositions with varying Cu : Ag molar feed ratio
Copper : Silver ratio Concentration Silver (µg/mL) Copper (µg/mL)
13:33:1 MIC 8.95 0.95 8.00
MBC 12.67 1.40 11.27
20:1 MIC 10.72 0.74 9.98
MBC 15.69 1.08 14.61
15:1 MIC 10.71 0.98 9.73
MBC 14.21 1.31 12.90
40:1 MIC 16.04 0.44 15.6
MBC 21.46 0.60 20.86

[000118] Of the above compositions, the most stable and efficient composition came from the 15:1 molar feed ratio of Cu-Ag nanoparticles. Above 20:1, the Cu nanoparticles tend to get unstable and oxidize.
[000119] Example 3: Surface Contamination Assessment
[000120] The presence of Adenosine Triphosphate (ATP) on substrate surfaces coated with the anti-microbial composition of Example 1 was measured to analyze the volume of microbial contamination. ATP is found in all biological cells, also known as cellular energy. A substrate surface is a non-living object and should not ideally contain ATP. If the assessment meter shows signs of ATP presence on the tested surface it is an indication of microbial contamination being present there which can cause infection via touch. The value in the meter was obtained in Relative Light Unit (RLU). The global interpretation of the reading obtained in the ATP Assessment Meter in RLU is provided below. Results of the test are provided in Table No. 2 below.
Parameters: ? 0 RLU - 100 RLU: No Contamination ? 101 RLU - 300 RLU: Low Contamination ? 301 RLU - 500 RLU: High Contamination ? Above 500 RLU: Heavy Contamination
Table No. 2: Results for surface contamination assessment
S. No. Substrate surface Before Coating After Coating
1 Toilet Seat Cover 7437 258
2 Door handles 6782 88
3 Cupboard handles 372 11
4 Switches 852 22
5 Fabrics 3436 135
6 Keys 475 14
7 Laptop 1003 22
8 Mask 1513 22
9 Elevator Buttons 402 5
10 B.E.S.T Buses 378 1

[000121] Example 4: Microbial assays of the composition
[000122] 4.1 Anti-bacterial testing:
[000123] The composition of Example 1 was subjected to anti-bacterial testing against Escherichia coli, Salmonella, Staphylococcus aureus, Pseudomonas, and Enterobacteriaceae. The test was performed by standard protocol of ISO 18593. The composition of the present disclosure showed significant anti-bacterial activity as disclosed in Table No. 3.
Table No. 3: Anti-bacterial test results for the composition
S. No. Microbiological parameters Result of analysis Limits
1 Escherichia coli Absent Absent
2 Salmonella Absent Absent
3 Staphylococcus aureus Absent Absent
4 Pseudomonas Absent Absent
5 Enterobacteriaceae <10 Max. 20

[000124] 4.2 Anti-viral testing:
[000125] Pre-sterilized sample of the composition of Example 1 was loaded with diluted viral suspension to 106 PFU/ ml. Virus suspension 0.4 ml was added to 50 mm x 50 mm of Test sample. It was covered with 40 mm x 40 mm LDPE film. Following exposure time, virus was eluted and neutralized by serial ten-fold dilution and assayed to determine surviving viruses in comparison with control sample (without the composition) in sq. cms. Virus assay was quantitative as Plaque forming unit (PFU) visible as area of clearance. Results are presented in Table No. 4.When tested as specified, the composition showed >99.96% reduction of virus in 30 minutes when tested by ISO 21702:2019 standard.
Table No. 4: Anti-viral test results of the composition
Quantitative Assessment of Anti-viral Activity - ISO21702:2019
Untreated: Average no. of Plaques recovered at 0 hours (U0): 3.00x 104 PFU/sq. cm Log = 4.47
Control sample: Average no. of Plaques recovered at 30 mins. (Ut): 3.20x 104 PFU/sq. cm Log = 4.50
Sample Identification Average No. of Plaques recovered from treated (At) Log of Plaques recovered from treated (At) Antiviral Activity (R) (Log Ut-At) Virus reduction percentage
Present composition <10 <1 >3.50 >99.96%

Where, R = antiviral activity,
Uo = Log of PFU recovered from Untreated specimen immediately after inoculation, in PFU/ cm2
Ut = Log of PFU recovered from Untreated specimen after 24 hrs. after inoculation, in PFU/cm2
At = Log of PFU recovered from Treated specimen after 24 hrs. after inoculation, in PFU/cm2
[000126] EXAMPLE 5: Anti-Viral activity of the composition after aging
[000127] 5.1: Anti-viral activity: The composition of Example 1 was tested for retention of anti-viral activity after 1 week of accelerated aging – 30 days. Pre-sterilized sample of the composition was loaded with diluted viral suspension to 106 PFU/ ml. Virus suspension 0.4 ml was added to 50 mm x 50 mm of Test sample. It was covered with 40 mm x 40 mm LDPE film. Following exposure time, virus was eluted and neutralized by serial ten-fold dilution and assayed to determine surviving viruses in comparison with control sample (without the composition) in sq. cms. Virus assay was quantitative as Plaque forming unit (PFU) visible as area of clearance. Results are presented in Table No. 5.When tested as specified, the composition showed >99.97% reduction of virus in 60 minutes when tested by ISO 21702:2019 standard. Thus, the composition retains its anti-microbial efficacy, specifically anti-viral efficacy even after 30 days.
Table No. 5: Anti-viral test results of the composition after aging
Quantitative Assessment of Anti-viral Activity - ISO21702:2019
Untreated: Average no. of Plaques recovered at 0 hours (U0): 3.20x 104 PFU/sq. cm Log = 4.50
Control sample: Average no. of Plaques recovered at 60 mins. (Ut): 4.50x 104 PFU/sq. cm Log = 4.65
Sample Identification Average No. of Plaques recovered from treated (At) Log of Plaques recovered from treated (At) Antiviral Activity (R) (Log Ut-At) Virus reduction percentage
Present composition after one week of accelerated aging <10 <1 >3.65 >99.97%

Where, R = antiviral activity,
Uo = Log of PFU recovered from Untreated specimen immediately after inoculation, in PFU/ cm2
Ut = Log of PFU recovered from Untreated specimen after 24 hrs. after inoculation, in PFU/cm2
At = Log of PFU recovered from Treated specimen after 24 hrs. after inoculation, in PFU/cm2
[000128] 5.2 Anti-viral activity on coated ceramic tile: A tile coated with the anti-microbial composition of Example 1 was exposed for 30 days to oil, urine and paan (700 wash cycle). MS2 Bacteriophage with E. coli as hosts were used for testing. Rest of the test was performed as per section 5.1 and the results are provided in Table No. 6.
Table No. 6: Anti-viral test results of the tile after aging
Quantitative Assessment of Anti-viral Activity - ISO21702:2019
Untreated: Average no. of Plaques recovered at 0 hours (U0): 8.40x 104 PFU/sq. cm Log = 4.92
Control sample: Average no. of Plaques recovered at 2 hours (Ut): 9.10x 104 PFU/sq. cm Log = 4.95
Sample Identification Average No. of Plaques recovered from treated (At) Log of Plaques recovered from treated (At) Antiviral Activity (R) (Log Ut-At) Virus reduction percentage
Present composition 390 2.59 2.36 99.57%

[000129] 5.3 Anti-viral activity on coated non-porous material: A stainless steel container and hanger were coated with the anti-microbial composition of Example 1. MS2 Bacteriophage with E. coli as hosts were used for testing after 35 days. The test was performed just as in section 5.1 and results are provided in Table No. 7.
Table No. 7: Anti-viral test results of the non-porous material after aging
Quantitative Assessment of Anti-viral Activity - ISO21702:2019
Untreated: Average no. of Plaques recovered at 0 hours (U0): 8.60x 104 PFU/sq. cm Log = 4.93
Control sample: Average no. of Plaques recovered at 2 hours (Ut): 9.20x 104 PFU/sq. cm Log = 4.96
Sample Identification Average No. of Plaques recovered from treated (At) Log of Plaques recovered from treated (At) Antiviral Activity (R) (Log Ut-At) Virus reduction percentage
Present composition 720 2.85 2.11 99.21

[000130] 5.4 Anti-viral activity on coated porous material: A fabric material (cushion cover) was coated with the anti-microbial composition of Example 1. MS2 Bacteriophage with E. coli as hosts were used for testing after 35 days. Test and control fabrics were cut into appropriately-sized swatches of 50 mm diameter and stacked. The numbers of swatches taken were enough to absorb the entire liquid inoculum of 0.5 ml quantity. Stock virus was standardized to prepare a test inoculum. Test and control materials were inoculated with the test virus, and incubated in a humid environment at 350C temperature for 2 hours contact time. The viral concentration was determined at "Time Zero" to verify the target inoculums using plaque assay techniques. Assay plates were incubated for 48 hours for the virus-host cell system. After the incubation period, following neutralization, the carrier suspensions were quantified to determine the levels of infectious virus survived and the assay was scored for titre of test virus. Adequate control was implemented to verify neutralization effectiveness of the antimicrobial agent with neutralizer (D/E broth) used. Percent reductions were computed for test fabric relative to the Time Zero enumeration(s) and results are provided in Table No. 8.

Table No. 8: Anti-viral test results of the porous material after aging
Sample Test Organism: MS2 Bacteriophaqe Log Reduction
of virus
at 2 hrs Percentage reduction of virus at 2 hours
Average PFU/Carrier
at 0 hours (B) Average PFU/Carrier
at 2 hours (A)
PFU Log PFU Log
Coated cushion cover after 35 days 9.30x104 4.96 <10 <1 >3.96 >99.98
Lab control – untreated fabric 9.60x105 4.98 0.00 0.00
where log reduction – log (A/B), and where B = Number of viable test microorganisms on the control carriers immediately after inoculation, and A = Number of viable test microorganisms on the test carriers after the contact time, and
where Percentage Reduction = (B - A/ B) x 100.
[000131] EXAMPLE 6: Comparative analysis
[000132] A comparative study was performed to assess the synergistic anti-microbial effect of the composition of the present disclosure. For comparison two control samples namely – Controller A (non-coated glass slide) and Controller B (pre-stabilized non-coated glass slide) were taken. The silver and copper nanoparticles were taken individually and in two combinations compositions comprising copper and silver in ratios of 13:1 and 20:1. Two samples of encapsulated silver and copper nanoparticles in a ratio of 13:1 and 20:1 were taken as per the present invention (Example 1). The test was carried out by coating the compositions on a glass surface. Pre-sterilized samples were loaded with viral suspension to 106 PFU/ml. Virus suspension 0.4 ml was added to 50 mm x 50 mm of Test substrate. It was covered with 40 mm x 40 mm LDPE film. Following exposure time, virus was eluted and neutralized by serial ten-fold dilution and assayed to determine surviving viruses in comparison with Control without test product in sq. cms. Virus assay was quantified as Plaque forming unit (PFU) visible as area of clearance. The results are provided in Figure 4. As can be seen, individual Ag nanoparticles and individual Cu nanoparticles show lower efficacy than both copper and silver nanoparticles combined. However, the combined copper and silver nanoparticles show lower efficacy than the encapsulated copper and silver nanoparticles over a period of time. As seen, 13:1 of encapsulated Cu+Ag is more effective/ antimicrobial than 20:1 Cu+Ag. It can be inferred that reduced amounts of nanoparticles are required for bringing about the same efficacy in the composition of the present disclosure.
Encapsulated Cu+Ag > Cu+Ag > Individual Ag > Individual Cu > Controller
[000133] Thus, encapsulating Cu+Ag nanoparticles with a silane as in the present composition gives more efficiency than mere combination of Cu+Ag nanoparticles.
[000134] From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein merely for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention and should not be construed so as to limit the scope of the invention or the appended claims in any way.

ADVANTAGES OF THE PRESENT INVENTION
[000135] The present disclosure provides an anti-microbial composition that is effective against a host of microbes.
[000136] The present disclosure provides an anti-microbial composition that is stable and shows lower oxidation of the components.
[000137] The present disclosure provides an anti-microbial composition that has improved adhesion to substrate surfaces.
[000138] The present disclosure provides an anti-microbial composition that maintains its efficiency with aging for longer time.
,CLAIMS:1. An anti-microbial composition comprising:
a) a plurality of copper and silver nanoparticles encapsulated by at least one silane; and
b) at least one quaternary ammonium compound encapsulated by at least one silane.
2. The composition as claimed in claim 1, wherein the copper and silver nanoparticles are present in a weight percentage range of 2% to 10% by weight of the composition.
3. The composition as claimed in claim 1, wherein the copper nanoparticles and silver nanoparticles are present in a ratio of 20:1 to 13:1.
4. The composition as claimed in claim 1, wherein the copper and silver nanoparticles are encapsulated by the silane to form a nanosol gel.
5. The composition as claimed in claim 1, wherein the quaternary ammonium compound is selected from N-alkyl-N-benzyl-N-N-Dimethyl ammonium chloride, dialkyldimethylammonium chloride, benzethonium chloride, methylbenzethonium chloride or combinations thereof.
6. The composition as claimed in claim 1, wherein the quaternary ammonium compound is present in a weight percentage range of 3% to 15% by weight of the composition.
7. The composition as claimed in claim 1, wherein the silane is selected from alkylsilane, vinylsilane, methacryloxysilane, aminosilane, acryloxysilane, epoxysilane, or combinations thereof.
8. The composition as claimed in claim 1, wherein the silane is selected from acetoxysilane, glycidoxypropyl trimethoxysilyl silane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3 dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane hydrochloride or combinations thereof.
9. The composition as claimed in claim 1, wherein the silane is present in a weight percentage range of 2% to 8% by weight of the composition.
10. The composition as claimed in claim 1, wherein the composition further comprises a solvent.
11. The composition as claimed in claim 10, wherein the solvent is selected from water, de-mineralized water, alcohol, isopropyl alcohol emulsions, paints, or varnishes.
12. The composition as claimed in claim 1, wherein the composition is an anti-microbial coating composition that is coated on a substrate surface in one or a plurality of layers.
13. An anti-microbial formulation comprising:
a) a plurality of copper and silver nanoparticles encapsulated by at least one silane;
b) at least one quaternary ammonium compound encapsulated by at least one silane; and
c) an additive.
14. A process for preparing an anti-microbial coating composition, wherein the process comprises the steps of:
a) preparing an aqueous solution of a plurality of copper and silver nanoparticles;
b) adding the aqueous solution of step a) to at least one silane with stirring to give a solution A;
c) preparing an aqueous solution of at least one quaternary ammonium compound;
d) adding and mixing the aqueous solution of step c) to at least one silane to obtain a solution B; and
e) grafting the solution A and solution B on a solvent to give the composition.
15. A method of inhibiting growth of or killing of microbes on a substrate surface comprising coating the anti-microbial composition as claimed in claim 1, on the substrate surface in an anti-microbially effective amount.
16. A manufacturing product or device coated with the anti-microbial composition as claimed in claim 1.