Face mask, composite material, iron-iron oxide composition, and methods for manufacturing and using the same

Abstract

The present invention generally relates to face masks. The present invention also generally relates to composite materials, iron-iron oxide compositions, and methods for their manufacture. In particular, an iron-iron oxide composition comprising an extract of cashew seed coat and iron particles and / or iron oxide core-shell particles. The iron-iron oxide composition can be used as an antimicrobial composition.

Description

Technical Field

[0001] The present invention generally relates to face masks. The present invention also generally relates to composite materials, iron-iron oxide compositions, and methods for manufacturing the same. Background Art

[0002] The development of microbial infections and antimicrobial resistance has received attention as one of the particularly important key issues faced by recent public health authorities. Microbial contamination refers to the unintentional or accidental introduction of microorganisms such as bacteria, yeasts, molds, fungi, viruses, prions, protozoa, or their toxins and by-products. The increasing number of hospital-acquired infection (HAI) cases has also drawn more and more attention.

[0003] Diseases caused by highly pathogenic viruses of animal origin have increasingly drawn the attention of health authorities. Recent prominent examples are disease outbreaks caused by SARS and MERS coronaviruses (SARS-CoV, MERS-CoV), avian influenza virus (AIV), and Ebola virus (EBOV). With increasing globalization, the threat of diseases caused by such highly pathogenic viruses has been amplified.

[0004] Highly pathogenic viruses or HP viruses include all viruses for which there is currently no vaccine, and these viruses can cause fatal systemic diseases in humans if left untreated.

[0005] As a specific example, recently, coronavirus disease (COVID-19) is an infectious disease caused by a new virus. This disease causes respiratory illness, and symptoms include coughing, fever, and in more severe cases, difficulty breathing. Another important commonality among all these viruses, apart from the fact that they can all cause fatal diseases in humans and there is no effective treatment method or vaccine in any case, is that they are all of animal origin, that is, they are initially transmitted from animals to humans. For example, the animal source of AIV is birds, the animal source of EBOV is fruit bats, and the animal source of COVID-19 is bats.

[0006] Another common feature is that they have a relatively high mortality rate in humans. In some cases, such as avian influenza, they have the potential to become pandemics, causing a large number of deaths and posing a major challenge to frontline healthcare workers at risk of being infected with the virus.

[0007] Such diseases are mainly transmitted through contact with an infected person when coughing or sneezing, or by touching a surface carrying virus particles and then touching the eyes, nose, or mouth. To prevent the spread of the disease, recommended measures include washing hands frequently, avoiding touching the face, and avoiding close contact (e.g., within 1 meter) with people who are unwell.

[0008] Alternatively, a face mask can be used. The face mask can cover the entire face or a part of the face. Certain face masks can be particularly suitable for medical purposes to protect the wearer from contamination and hazardous particles, or to prevent the wearer from spreading pathogens.

[0009] Medical surgical face masks are typically worn by healthcare professionals and patients to prevent the spread of bacteria and / or viruses. Such face masks can capture bacteria and virus particles released from the mouth and nose of the wearer. However, such face masks are usually loose, and the exhaled air of the wearer flows around the perimeter of the face mask, usually around the lower edge of the wearer's cheeks and around the chin. Therefore, there are concerns about the effectiveness of such face masks in protecting patients and healthcare professionals.

[0010] In a systematic review aimed at discovering the effectiveness of physical interventions in blocking or reducing the transmission of respiratory viruses, the study showed that wearing a face mask can significantly reduce the transmission of respiratory viruses, with an odds ratio of 0.45 for handwashing and an odds ratio of 0.09 for wearing an N95 face mask. This indicates that by taking hygiene measures, the transmission of respiratory viruses can be effectively prevented among young children and within families using only face masks.

[0011] However, medical surgical face masks are only suitable for single use. If the face mask is reused, the risk of infection will increase significantly. This, in turn, causes environmental problems because such face masks are usually plasticized paper products. In this regard, the use of medical surgical face masks is not sustainable.

[0012] In addition, proper disposal of the face mask is required to correctly control the spread of the disease. It has been observed that after using disposable face masks, the situation of littering has increased, which may promote the spread of the disease.

[0013] Another problem with existing face masks is that they are not convenient to store when not in use.

[0014] Another problem is that face masks are usually made as a "one-size-fits-all" product and cannot adapt to the face shapes or head shapes of different users, potentially making it difficult for users to ensure that the face mask fits tightly enough to the face.

[0015] The increasing concern for cleanliness in various industries has led to an increased demand for antimicrobial products. They can be used to protect surfaces from microorganisms and are applied in medical devices and packaging. Due to population growth and urbanization, the demand for antimicrobial additives is also expanding rapidly.

[0016] For this reason, the global market size of antimicrobial coatings in 2019 was estimated to be 7.1 billion US dollars, and the compound annual growth rate (CAGR) from 2020 to 2027 is expected to be 12.8%.

[0017] Currently, antimicrobial products on the market mainly rely on titanium, zinc, and silver compounds to impart antimicrobial effects. Although effective, these elements are expensive and toxic, and are prone to heavy metal contamination. Due to the dependence of these products on light irradiation, their antimicrobial efficacy is also very low.

[0018] There are further concerns about whether such products are toxic to humans and animals. In addition, when using irritating chemicals in the synthesis process, there is always a possibility of leaving toxic precursors such as heavy metals in the final product, so extensive cleaning is required. This increases the production cost.

[0019] It is desired to overcome or alleviate at least one of the above problems, or at least provide a useful alternative. Summary of the Invention

[0020] The present invention is based on the understanding that certain natural products have antimicrobial effects. In particular, the inventors have found that the advantage of the cashew seed coat extract lies in its antimicrobial efficacy. For example, it has been found that the natural product extract has antibacterial properties against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, and has anticancer properties against human hepatocellular carcinoma cell line HEPG2. The natural product extract can be applied in green solvents and can have a permeation effect when tested on surfaces and textiles. In addition, when combined with other components, a synergistic (or at least additive) antimicrobial effect is observed. For example, the cashew seed coat extract can be used as a precursor for synthesizing iron particles and / or iron oxide particles. Since these compositions are synthesized / made from biological or natural materials, they are safe for humans and animals. This green biosynthesis is cost-effective, generates less waste, is non-toxic and environmentally friendly. The application of the present invention is an antimicrobial finishing agent for textiles.

[0021] The present invention provides an iron-iron oxide composition, comprising:

[0022] a) a cashew seed coat extract; and

[0023] b) iron-iron oxide core-shell particles, with the core being a single iron core or an iron alloy core and the shell being an iron oxide shell;

[0024] wherein the cashew seed coat extract comprises components selected from the group consisting of proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from the group consisting of tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or combinations thereof; and

[0025] wherein the iron-iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof.

[0026] In some embodiments, the iron-iron oxide particles are also at least partially passivated by carboxylic acid moieties or hydroxyl moieties.

[0027] In some embodiments, the carboxylic acid is selected from fatty acids, aromatic carboxylic acids, diacids, tricarboxylic acids, keto acids, α-hydroxy acids, divinyl ether fatty acids, phosphoric acid, polyphosphoric acid, tungstic acid, vanadic acid, molybdic acid, heteropolyacids, or combinations thereof.

[0028] In some embodiments, the iron-iron oxide particles comprise elemental Fe, FeO, Fe2O3, Fe3O4, or combinations thereof.

[0029] In some embodiments, the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm.

[0030] In some embodiments, the shell further comprises components from cashew nut shell extract.

[0031] In some embodiments, the thickness of the shell is from about 5 nm to about 1 μm.

[0032] In some embodiments, relative to the iron-iron oxide composition, the iron content of the iron-iron oxide composition is from about 20 wt% to about 80 wt%, and the oxygen content is from about 15 wt% to about 40 wt%.

[0033] In some embodiments, relative to the iron-iron oxide composition, the carbon content of the iron-iron oxide composition is from about 4 wt% to about 50 wt%.

[0034] In some embodiments, the iron-iron oxide composition further comprises excipients selected from stabilizers, dispersants, colorants, or combinations thereof.

[0035] The present invention also provides a method for synthesizing an iron-iron oxide composition, comprising:

[0036] reacting a cashew nut shell extract with iron particles and an iron oxide precursor to form iron-iron oxide core-shell particles having an elemental iron core or an iron alloy core and an iron oxide shell;

[0037] wherein the cashew nut shell extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof; and

[0038] wherein the iron particles and / or the iron oxide particles are at least partially passivated by the cashew nut shell extract.

[0039] In some embodiments, the iron oxide precursor is an iron(III) salt.

[0040] In some embodiments, the anion of the iron(III) salt is selected from nitrates, chlorides, bromides, fluorides, iodides, sulfates, oxalates, perchlorates, phosphates, tetrafluoroborates, or combinations thereof.

[0041] In some embodiments, the reaction is carried out at about 5 °C to about 80 °C.

[0042] In some embodiments, the reaction proceeds for about 1 minute to about 24 hours.

[0043] In some embodiments, the iron particles and the iron oxide precursor are uniformly mixed before reacting with the cashew seed coat extract.

[0044] In some embodiments, when the cashew seed coat extract contains phenolic compounds, the weight ratio of the phenolic compounds to the iron particles and the iron oxide precursor is about 1:500 to about 500:1.

[0045] The present invention also provides a method for disinfecting an abiotic surface, which comprises:

[0046] a) contacting the iron-iron oxide composition disclosed herein with the abiotic surface.

[0047] In some embodiments, the method further comprises the step of applying the iron-iron oxide composition to an application medium before (a).

[0048] The present invention also provides a method for killing microorganisms in the dark by using the iron-iron oxide composition disclosed herein.

[0049] The present invention also provides a method for disinfecting a surface using an iron-iron oxide composition, wherein after 5 minutes, the iron-iron oxide composition can provide at least a 2-log decrease in microbial activity.

[0050] The present invention also provides a composite material, which comprises a porous fabric impregnated with an iron-iron oxide composition and is coated with a waterproof coating on at least one side of the porous fabric,

[0051] wherein the iron-iron oxide composition is present in an amount of about 0.1 wt% to about 5 wt% relative to the composite material;

[0052] wherein the thickness of the waterproof coating is about 10 μm to about 500 μm.

[0053] It should be understood that the composite material can be used to form the facial covering structure of the face mask and / or the composite fabric layer. This is premised on the understanding that while antibacterial and antiviral compounds / compositions can be applied to hard, non-porous surfaces to provide desirable effects, the use of antibacterial and antiviral compounds / compositions on porous surfaces has not been tested. Additionally, due to cost reasons, it is not commercially and economically viable to apply antibacterial and antiviral compounds / compositions on disposable face masks. Advantageously, the composite material provides protection against inhaling viral and bacterial cells. The composite material also functions to kill viral and bacterial cells that come into contact with the composite layer of the face mask. More advantageously, since the iron-iron oxide composition remains in the composite material even after the face mask has been washed 20 times, the face mask can be reused. In this regard, at least 70% of the iron-iron oxide composition remains in the composite fabric layer after 20 washes.

[0054] In some embodiments, the porous fabric of the composite material is a fabric comprising cotton and spandex, wherein the cotton is approximately 90% by weight and the spandex is approximately 10% by weight relative to the fabric.

[0055] In some embodiments, the iron-iron oxide composition comprises iron, iron(II) oxide, and iron(III) oxide.

[0056] In some embodiments, the iron-iron oxide composition comprises elemental Fe, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof.

[0057] In some embodiments, the amino acid, carbohydrate, or mixture thereof is selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, zein, glucose, galactose, fructose, xylose, sucrose, lactose, maltose, trehalose, sorbitol, mannitol, maltodextrin, raffinose, stachyose, fructooligosaccharide, amylose, amylopectin, modified starch, glycogen, cellulose, hemicellulose, ethyl cellulose, methyl cellulose, pectin, hydrocolloid, and combinations thereof.

[0058] In some embodiments, the particle size of the iron-iron oxide composition is from about 1 μm to about 800 μm.

[0059] In some embodiments, the thickness of the shell is from about 50 nm to about 400 nm.

[0060] In some embodiments, the waterproof coating is selected from perfluorobutanesulfonic acid, perfluorooctanoic acid, perfluorohexanoic acid, Scotchgard, perfluorooctanesulfonic acid, paraffin (and other hydrocarbon-based solutions), silica nanoparticles, and silanes (such as alkyltrialkoxysilanes).

[0061] Advantageously, the waterproof coating on the composite material can provide fluid resistance to the outer composite fabric layer, thereby providing a better air droplet shielding effect to the user.

[0062] The present invention also provides a method for manufacturing a composite material, which includes:

[0063] a) impregnating a porous fabric with an iron-iron oxide composition; and

[0064] b) coating the porous fabric with a waterproof coating on at least one side of the porous fabric to form a composite material,

[0065] wherein the iron-iron oxide composition is present in an amount of about 0.1 wt% to about 5 wt% relative to the composite material;

[0066] wherein the thickness of the waterproof coating is about 10 μm to about 500 μm.

[0067] The present invention provides a face mask, which includes:

[0068] a facial covering structure configured to cover at least the mouth and nasal passages of the user; and

[0069] a connecting structure, which includes:

[0070] drawstrings connected to opposite sides of the facial covering structure, which are used to fix the facial covering structure to the user's face; and

[0071] fasteners releasably connected to the drawstrings to hold the drawstrings in a tightened or loosened position;

[0072] wherein the drawstrings are arranged to form an ear loop for surrounding behind the corresponding ears of the user and a neck loop for surrounding behind the user's neck; and wherein the fasteners are connected to the neck loop; and

[0073] wherein the facial covering structure comprises the composite material disclosed herein.

[0074] Advantageously, the connecting structure provides greater convenience for the user to tighten the face mask to prevent the entry or exit of pathogen-carrying droplets and provide a more effective barrier, and also provides greater convenience for storage when not in use.

[0075] The fastener can be a cord lock.

[0076] In some embodiments, each ear strap includes a drawstring portion that is attached at a first point on a relative side and passes through a connecting loop at a second point spaced apart from the first point.

[0077] The neck strap may include a drawstring portion that spans between respective connecting loops.

[0078] In some embodiments, the drawstring passes through the eyelet of a buckle.

[0079] In some embodiments, the facial covering structure includes a nose pad on its inner surface.

[0080] The facial covering structure may include a filter layer. For example, the filter layer may be sandwiched between an outer fabric layer and an inner fabric layer. The outer fabric layer may be a composite fabric layer.

[0081] In some embodiments, the filter layer is replaceable. For example, the facial covering structure may include a sleeve for receiving the filter layer.

[0082] In some embodiments, the facial covering structure is configured to at least partially cover the submental triangular region of the user.

[0083] In some embodiments, the facial covering structure further includes a lower fabric that is attached to the longitudinal sides of the outer fabric layer and the inner fabric layer and is away from the nose pad, such that in use, the lower fabric is attached to the facial covering structure at an angle greater than 20°. In some embodiments, the facial covering structure is configured to at least partially cover the zygomatic region of the user.

[0084] In some embodiments, the facial covering structure further includes two extensions, each extending from a first point on opposite sides of the facial covering structure for attachment to a drawstring.

[0085] Advantageously, this reduces the pulling pressure of the ear straps on the ears, thus providing greater comfort to the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] As a non-limiting example, embodiments of the present invention will now be described with reference to the accompanying drawings, wherein:

[0087] Figure 1 is a front view of a face mask according to certain embodiments;

[0088] Figure 2 is an isometric view of the face mask seen from the upper left;

[0089] Figure 3 is a left view of the face mask;

[0090] Figure 4 is a rear view of the face mask;

[0091] Figure 5 is an exploded view of the face mask, showing the part thereof located on the user's face;

[0092] Figure 6 is a left rear view of a user wearing the face mask, showing the connection of the mask's laces to the user's ears;

[0093] Figure 7 is a left front view of a user wearing the face mask;

[0094] Figure 8 shows the user with the face mask in the storage position;

[0095] Figure 9 is a rear view of another example of a face mask according to certain embodiments;

[0096] Figure 10 shows the insertion of Figure 9 a replaceable filter layer in the face mask;

[0097] Figure 11 is an isometric view of another face mask according to certain embodiments;

[0098] Figure 12 is a right view of the face mask;

[0099] Figure 13 is a schematic diagram of a hypothetical interaction that inhibits viruses;

[0100] Figure 14 is an exemplary schematic diagram of a cashew seed coat extract composition;

[0101] Figure 15 is an exemplary schematic diagram of a cashew seed coat extract composition;

[0102] Figure 16 shows the degradation of Coomassie Brilliant Blue R dye upon contact with the cashew seed coat extract composition;

[0103] Figure 17 shows the degradation of Coomassie Brilliant Blue R dye upon contact with the cashew seed coat extract composition;

[0104] Figure 18 shows the measurement results of OH radicals after exposure to the cashew seed coat extract composition;

[0105] Figure 19 shows the measurement results of O2 radicals after 2 h of exposure to the cashew seed coat extract composition; and

[0106] Figure 20A - Figure 20E shows a scanning electron microscope (SEM) image of an iron-iron oxide composition. Detailed Description

[0107] Embodiments of the present invention relate to a face mask having a connection structure that provides greater convenience for a user to tighten the face mask to provide a more effective barrier against the entry or exit of pathogen-carrying droplets, and also provides greater convenience for storage when not in use.

[0108] First refer to Figures 1 to 4 , the face mask 100 according to certain embodiments includes a face covering structure 110. The face covering structure 110 is configured to cover at least the mouth and nasal cavity of the user. For example, as shown in Figure 6 and Figure 7 , the face covering structure 110 can extend above the tip of the user's nose and, in some instances, can extend to about half of the bridge of the nose. The face covering structure 110 has an upper contour 116 that has a recessed central portion 118 at the bridge of the nose position.

[0109] The face covering structure 110 comprises a composite material disclosed herein. The composite material provides an antimicrobial function for the face mask by capturing and killing microorganisms near or on the surface of the face covering structure.

[0110] The face mask 100 further includes a connection structure for securing the face covering structure 110 to the user's face. Drawstrings are attached to opposite sides of the face covering structure 110. For example, in the rear view as shown in Figure 4 , the opposite ends of the drawstrings are attached at points 102 and 104 on the upper opposite sides of the face covering structure 110. The opposite ends can be attached at points 102, 104 by any suitable method, such as by stitching, adhesive, heat bonding, etc.

[0111] The drawstrings are arranged to form a pair of ear loops 122, 124. In use, the ear loops 122, 124 are looped around the respective ears of the user (see Figure 6 and Figure 7 , which shows the left ear loop looped around the user's left ear).

[0112] The drawstrings are also arranged to form a neck strap 150 that loops around the back of the user's neck, which can be formed by a portion of the drawstring that spans between connection rings 112, 114 located on opposite sides of the face covering structure 110.

[0113] The connection structure further includes a fastener 140 that is releasably connected to the drawstring, particularly to the neck strap 150. The fastener is arranged to hold the drawstring in a loose or tightened position as needed.

[0114] For example, to tighten the drawstring to hold the face covering portion 110 tightly against the user's face, the user can release the fastener 140, pull the neckband 150 in a direction away from their neck to shorten the neckband 150, and then reconnect the fastener 140 to hold the drawstring in the tightened position.

[0115] To loosen the drawstring, for example when the face mask is not needed, the user can release the fastener 140 again and lengthen the neckband 150, such as by pulling the face covering portion 110 away from their face, and then reconnect the fastener 140 to hold the drawstring in the loosened position. Advantageously, as Figure 8 shown, the neckband 150 remains looped around the user's neck and the loosened drawstring can be used to store the face covering portion 110. This provides the user with a "hands-free" convenience as the face mask can hang around her neck when loosened; additionally, if the face mask needs to be removed temporarily, there is no need to store the face mask in a storage bag.

[0116] By providing the neckband 150 in addition to the ear loops 122, 124, the face mask 100 is held more securely on the user's head, reducing the risk of the face mask falling off when the user is "busy" as the laces secure the face mask 100 to the head and ears, rather than just the ears.

[0117] For example, the fastener 140 can be a cord lock. The cord lock 140 can have a buckle body 142 with a pair of eyelets 144a, 144b to receive the drawstring. The cord lock 140 also includes a plunger 146 that is biased by a spring or other biasing element to snag the drawstring when the drawstring passes through the eyelets 144a, 144b. The plunger 146 can be depressed to release the drawstring to enable shortening or lengthening of the neckband 150.

[0118] As described above, the fastener is connected to the neckband 150 and is typically located in its middle portion such that the end portion 152 of the neckband 150 can be grasped when the user wishes to tighten the neckband 150 and thus tighten the face covering portion 110.

[0119] In some embodiments, the first ear loop 122 includes a drawstring portion that is connected at a first point 102 on one opposite side of the face covering structure 110 and passes through a connecting loop 112 at a second point spaced apart from the first point 102. The first point 102 can be located at or near the top of the face covering structure 110, such as on a wing portion 101 that extends from an upper region of the face covering structure 110 to the user's cheekbone when the face mask 100 is worn ( Figure 7)。Similarly, the second ear strap 124 includes a drawstring portion that is connected at a first point 104 on the other opposite side of the face covering structure 110 and passes through the connecting loop 114 at a second point spaced apart from the first point 104. The first point 104 may be located on the wing portion 103 that extends from the upper region of the other side of the face covering structure 110 to extend to the other cheekbone of the user.

[0120] The ear straps 122 and 124 and the neck strap 150 may be formed by passing drawstrings through the connecting loops 112, 114 provided on opposite sides of the lower portion of the face covering part 110. The lower end of the ear strap 122 may pass through the connecting loop 112, and similarly, the lower end of the ear strap 124 may pass through the connecting loop 114. Thus, the lower ends of the respective ear straps 122 and 124 transition to the respective ends of the neck strap 150. By arranging the ear straps 122, 124 and the neck strap 150 in this way, the mask 100 can be tightened at the ear region and the neck region by a single pull of the drawstring, for example by grasping and pulling the end 152 of the neck strap 150.

[0121] Facilitating the tightening of the mask 100 in this way also increases the likelihood that a tight seal can be formed around the user's face, regardless of their face shape. Thus, the mask 100 can be more personalized than existing "one-size-fits-all" products.

[0122] The connecting structure can be incorporated into the mask 100 in the following manner. First, the connecting loops 112 and 114 are fixed on opposite sides of the lower portion of the face covering structure 110 (e.g., by stitching, although other methods are possible). Next, the first end of a cord formed of a section of material (which can be a textile or fabric material or a polymer material) is connected at a connection point 102 on the wing portion 101. This connection can be made by stitching, adhesive, heat sealing, binding, or any other suitable means. Then, the cord is looped around the first connecting loop 112 to form the first ear strap 122. Next, the cord passes through the eyelet 144b of the buckle 140, loops around, and passes back through the eyelet 144a and the second connecting loop 114 to form the neck strap 150, where the end loop 152 of the neck strap 150 is located on the side of the buckle 140 away from the ear strap 122. Finally, the second end of the cord is connected to a connection point 104 on the wing portion 103, similar to the connection of the first end at the connection point 102.

[0123] In at least some embodiments, the face covering structure 110 may include a layered structure, at least including a filter layer. The filter layer may be sandwiched between an outer fabric layer (e.g., a composite fabric layer) and an inner fabric layer.

[0124] For example, as Figure 5As shown in the exploded view, the facial covering structure 110 may include a filter layer 320 sandwiched between an outer composite fabric layer 310 and an inner fabric layer 330.

[0125] In some embodiments, the outer composite fabric layer 310, the inner fabric layer 330, and the filter layer 320 are stitched together to form the facial covering structure 110.

[0126] In some embodiments, the facial covering structure may include a nose pad (not shown) that is positioned within the facial covering structure to cushion the user's nose bridge during use. For example, the nose pad may be embedded or secured within the inner fabric layer 330, such as in the bridging region 118 of the facial covering structure 110. In some embodiments, part or all of the inner layer 330 may be filled to provide a desired cushioning function. The nose pad advantageously improves the user's comfort while also helping to ensure that the edges of the facial covering structure 110 are closer to the user's face.

[0127] In some embodiments, the facial covering structure 110 is configured to extend from the user's nose bridge to the bottom of the mental protuberance during use. In other embodiments, the facial covering structure 110 is configured to cover the user's mental protuberance or mental region during use. In other embodiments, the facial covering structure 110 is configured to at least partially cover the submental triangle region of the user during use. As Figure 7 shown.

[0128] In some embodiments, the facial covering structure further includes a lower fabric connected to the longitudinal sides of the fabric layer and the inner fabric layer and away from the nose pad. Thus, during use, the lower fabric is connected to the mask structure at an angle greater than 10°. In other embodiments, the angle is greater than 15°, 20°, 25°, 30°, 35°, 40°, 50°, 60°, 70°, 80°, 90°, or 100°.

[0129] Advantageously, the lower fabric drapes as a sheet to provide more coverage to the user. Additionally, the sheet-like drape allows for more contact between the mask and the user's face, thus providing the user with a better sense of security.

[0130] In some embodiments, the facial covering structure 110 is configured to at least partially cover the user's cheek region during use. In other embodiments, the facial covering structure 110 is configured to at least partially cover the user's zygomatic region during use.

[0131] In some embodiments, the facial covering structure further includes two extensions, each extending from a first point on opposite sides of the facial covering structure for connection to drawstrings. As Figure 7 shown.

[0132] Advantageously, when in use, the coverage of the facial covering structure substantially extends to the user's ears, providing greater assurance for better protection for the user. This also prevents (or at least reduces) the possibility of accidentally removing the face mask. In addition, the extension also reduces the pressure on the ears by the ear straps, thus being more comfortable.

[0133] In some embodiments, the outer composite fabric layer 310 is a porous fabric containing cotton and spandex, wherein relative to the fabric, cotton is about 90% by weight and spandex is about 10% by weight.

[0134] In some embodiments, the inner fabric layer 330 is a quick-drying fabric. As used herein, "quick-drying fabric" refers to a fabric that dries quickly. In this regard, the drying rate of the quick-drying fabric is about 1.35 times that of an untreated fabric. For example, this quick-drying property can be provided by a chemical coating that can increase the drying rate of the fabric. Examples of quick-drying fabrics include nylon, polyester, merino wool, cotton, and cotton-polyester blended fabrics.

[0135] In some embodiments, the filter layer 320 is a non-woven filter layer. In some embodiments, the filter layer 320 is a non-woven fabric filter layer. There are two main manufacturing methods for non-woven fabrics: felting or bonding. Fabrics use fibers instead of yarns; they are laid in a random or uniform manner to form a web layer. Non-woven fabrics are fabric-like materials made of short fibers (short) and filaments (continuous long) and can be bonded together by chemical, mechanical, thermal, or solvent treatment.

[0136] Examples of non-woven filter layers include charcoal fabric, bamboo fiber fabric, and meltblown polypropylene. Meltblown polypropylene can also contain charcoal, bamboo fiber, or nanomaterials to improve the filtration efficiency. Polytetrafluoroethylene (PTFE) membranes can also be used because they can withstand better wear and tear and immersion in water.

[0137] In some embodiments, the pore size of the filter layer 320 is less than 2.5 μm. In other embodiments, the pore size of the filter layer 320 is less than 2 μm, 1.5 μm, 1 μm, 0.8 μm, 0.5 μm, or 0.1 μm. In other embodiments, the filter layer 320 is capable of filtering particles with a particle size greater than 1 μm. In other embodiments, the filter layer 320 is capable of filtering particles with a particle size greater than 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, or 0.1 μm.

[0138] In some embodiments, the filter layer 320 is capable of filtering particles having a size greater than 0.3 μm. In some embodiments, the filtration efficiency is at least about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 98%. In other embodiments, the filter layer 320 is capable of filtering particles having a size greater than 0.3 μm and having an efficiency of at least about 80%.

[0139] In some embodiments, the filter layer 320 is capable of filtering particles having a size of about 0.1 μm. In some embodiments, the filtration efficiency is at least about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 98%. In other embodiments, the filter layer 320 is capable of filtering particles having a size of about 0.1 μm and having an efficiency of at least about 80%.

[0140] In some embodiments, the face mask 100 has the following properties:

[0141] a) Outer layer (310) - fluid resistant;

[0142] b) Antimicrobial layer ( Figure 5 not shown in, but may be provided on the outer layer 310) - an antimicrobial fabric layer for capturing and killing microorganisms (virus and bacterial cells);

[0143] c) Inactive layer (320) - special non-woven fibers for filtering external particulate matter; and

[0144] d) Inner layer (330) - fast-drying cooling mesh layer.

[0145] The outer layer and the antimicrobial layer may be part of the outer composite fabric layer 310. The composite fabric layer may be made of the composite materials disclosed herein. This provides the face mask 100 that is comfortable to use and effective in preventing and / or blocking the spread of diseases.

[0146] In some embodiments, the face mask 100 is capable of filtering particles having a size greater than 1 μm. In other embodiments, the face mask is capable of filtering particles having a size greater than 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm or 0.2 μm.

[0147] In some embodiments, the fine particulate matter rating of the face mask 100 is 2.5 (PM 2.5 ). PM 2.5 refers to particulate matter having a diameter of 2.5 μm or less than 2.5 μm. PM 2.5 is generally described as fine particulate matter. In this regard, the face mask 100 is capable of filtering particles down to 2.5 μm.

[0148] In some embodiments, the face mask 100 has a bacterial filtration efficiency of at least 90% after 30 days. In other embodiments, the bacterial filtration efficiency is at least 98%, at least 96%, at least 94%, at least 92%, at least 90%, at least 85%, at least 80%, at least 75%, at least 70%, at least 65% or at least 60%.

[0149] In some embodiments, the antibacterial effect of the face mask 100 is at least 90% after 24 hours. In other embodiments, the antibacterial effect is at least 98%, at least 96%, at least 94%, at least 92%, at least 90%, at least 85%, at least 80%, at least 75%, at least 70%, at least 65% or at least 60%.

[0150] In some embodiments, the antiviral effect of the face mask 100 is at least 0.5-log unit of inhibition after 24 hours. The effect can be compared with a control group. In other embodiments, the antiviral inhibition is at least 1-log unit, at least 1.5-log units, at least 2-log units, at least 2.5-log units, at least 3-log units, at least 3.5-log units, at least 4-log units or at least 4.5-log units.

[0151] In some embodiments, the outer composite fabric layer 310 and the filter layer 320 are fused together. A heat transfer fusing machine can be used for fusing.

[0152] The composite fabric layer 310 may comprise a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; and wherein the thickness of the waterproof coating is about 10 μm to about 500 μm.

[0153] The composite fabric layer 310 of the face mask can be processed or cut from a composite material.

[0154] It is envisioned that a composite material having antibacterial properties and / or antiviral properties may be advantageous. The composite material can be used as the inner layer (the side facing the user) of the face mask, or as the outer layer (the exposed side) of the face mask. The composite material can also be used as a sandwich layer such that both of its sides are protected and / or covered by fabric. For this purpose, the inventors have found that when the iron-iron oxide composition is applied to the porous fabric material in a specific manner, protection can be provided to the user. Without being limited by theory, it is believed to have the ability to kill viruses and bacteria upon contact. When the composite material is applied as a substrate or layer to the face mask, the face mask can not only protect the user by the inhalation route, but also kill viruses and bacteria in contact with the surface of the face mask.

[0155] It is speculated that the composite material will capture microorganisms by mimicking the positions where microorganisms usually attach to human cells, and then destroy them by disrupting their surfaces (viruses) and cell walls (bacteria). It has been found that the composite material can kill the germs causing influenza A, avian influenza, SARS, measles, pneumonia, common cold, tuberculosis, herpes, MRSA, and gastroenteritis.

[0156] The antibacterial activity is thought to be through the following mechanism: proteins on the microbial membrane can bind to the composite material, thereby disrupting the structure and function of bacterial cells. Further complexation with essential metal ions also inhibits the formation of fibrin.

[0157] In addition, it can also play an antiviral role. The composite material can attack different stages of the virus replication process. This includes the extracellular virus particles themselves during virus attachment to cells ( Figure 13 ), during virus entry into cells, during virus replication in host cells, and during the assembly of new virus particles, transport proteins, polysaccharides, and viral enzymes. In almost all of the above stages, the composite material will permanently bind to the proteins of the capsid or supercapsid. The proteins can be specific viral enzymes required for virus replication or newly synthesized viral proteins involved in the production of new virus particles.

[0158] The development of microbial infections and antimicrobial drug resistance has drawn attention as one of the most important key issues faced by public health and safety. The invention of a clean antimicrobial surface with long-term stability and activity has great application prospects, and its applications cover almost all aspects of our daily life, such as medical devices, hospital surfaces, textiles, packaging, electrical appliances, marine antifouling, filters, and public surfaces. Inorganic antimicrobial materials, especially semiconductor antimicrobial materials, are not easily chemically contaminated and have long-term stability. Some metals or metal oxides, such as silver, zinc oxide, and titanium oxide particles, have been used as antimicrobial components in various products or antimicrobial surface coatings. However, these materials also have limitations, such as heavy metal pollution / toxicity (for silver-based materials). For ZnO and TiO2 materials, due to their dependence on light irradiation, their antimicrobial efficacy is low and their applications are limited. In addition, another problem with nanomaterials is the uncertainty of nanotoxicity.

[0159] Advantageously, the inventors have found that iron-based antimicrobial materials are non-toxic, highly active against microorganisms, very stable, and have long-term activity. For example, under non-organic solvent conditions, an iron-iron oxide composition can be synthesized by modifying iron powder (micron-sized) with carbohydrates, amino acids, food additives, or nutrients. This can be accomplished, for example, using a fluidized bed reactor.

[0160] Iron powder has redox activity and will react slowly with oxygen and moisture to form iron oxides and release hydrogen gas. Iron powder itself does not produce reactive oxygen species (ROS) and does not kill bacteria. Some iron cations may be released from iron powder, but the concentration is very low and harmless to cells.

[0161] Advantageously, by modifying iron powder (micron-sized) with carbohydrates, amino acids, food additives or nutrients, the iron particles can have a nanostructured protective shell covering the iron core. The shell can be formed by the reaction of iron with carbohydrates, amino acids, food additives under non-organic solvent conditions. The core-shell structure creates a special interface between the iron core and the iron complex shell, changing the potential of the iron core and the redox reaction pathway. Therefore, the iron particles can react with oxygen and moisture to produce ROS. Iron oxides and hydroxides remain in the core part. In this way, the iron particles can produce different ROS, including superoxide, singlet oxygen and hydroxyl radicals. Then the ROS can kill the contacted bacteria and viruses. The ROS killing mechanism of this material is similar to photocatalytic materials such as ZnO and TiO2. The ROS generation mechanism of this material is different from that of photocatalytic materials. It is a self-catalytic material and does not rely on light irradiation to produce ROS. The iron particles sacrifice the iron core to produce ROS.

[0162] Therefore, the present invention also provides a composite material, which comprises a porous fabric impregnated with an iron-iron oxide composition and is coated with a waterproof coating on at least one side of the porous fabric,

[0163] wherein the iron-iron oxide composition is present in an amount of about 0.1% to about 5% by weight relative to the composite material;

[0164] wherein the thickness of the waterproof coating is about 10 μm to about 500 μm.

[0165] It should be understood that with respect to the composite material, its main use is to produce face masks. Advantageously, the composite material and / or the face mask 100 provide protection against inhaling or spreading viruses and / or bacterial cells. The composite material and / or the face mask 100 also function to kill the viruses and bacterial cells contacting the composite layer 310 of the face mask 100. More advantageously, since the iron-iron oxide composition remains in the composite material even after the face mask is washed 20 times, the face mask can be reused. In this regard, at least 70% of the iron-iron oxide component remains in the composite fabric layer after washing 20 times.

[0166] As used herein, "composite material" is a material made of two or more component materials having significantly different physical or chemical properties, which, when combined, produce a material having properties different from those of each component. Each component remains independent and distinct in the finished structure. In this regard, the presently disclosed composite material has the ability to kill viruses and bacteria and can be washed at least 30 times.

[0167] As used herein, "impregnation" means to soak or saturate (something) with a substance. In this regard, the porous fabric is soaked with the iron-iron oxide composition.

[0168] In some embodiments, the iron-iron oxide composition is impregnated / present at about 0.1 wt% to about 5 wt% relative to the composite material. In this regard, the dry mass of the iron-iron oxide composition is about 0.1 wt% to about 5 wt% relative to the dry mass of the final composite material. In other embodiments, the impregnation amount is about 0.1 wt% to about 4 wt%, about 0.1 wt% to about 3 wt%, about 0.1 wt% to about 2 wt%, about 0.1 wt% to about 1 wt%, or about 0.1 wt% to about 0.5 wt%. In other embodiments, the impregnation amount is less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt% or less than 0.2 wt%.

[0169] Advantageously, the impregnation of the iron-iron oxide composition in the porous fabric allows for the uniform dispersion of iron particles in the composite material. In this regard, the iron-iron oxide composition remains in the composite material. When used to form the face mask 100, during use, moisture or water vapor from the user's mouth passes through the porous fabric, thus "activating" the iron particles. In the presence of oxygen and water, iron is converted to iron oxide and releases ROS in the process. In this regard, a reservoir of ROS is continuously available when the face mask is in use.

[0170] In some embodiments, the iron-iron oxide composition comprises iron, iron(II) oxide, and iron(III) oxide. In some embodiments, the iron content is greater than 90 wt% relative to the iron-iron oxide composition. In other embodiments, the iron content is greater than 91 wt%, greater than 92 wt%, greater than 93 wt%, greater than 94 wt%, greater than 95 wt%, greater than 96 wt% or greater than 97 wt% relative to the iron-iron oxide composition. In other embodiments, the content of iron(II) oxide and iron(III) oxide is less than 10 wt% relative to the iron-iron oxide composition. In other embodiments, the content of iron(II) oxide and iron(III) oxide is less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt% or less than 3 wt% relative to the iron-iron oxide composition.

[0171] In some embodiments, the iron is elemental iron. In other embodiments, the iron(II) oxide is FeO. In other embodiments, the iron(II) oxide is Fe2O3. In other embodiments, the iron(II) oxide and iron(III) oxide is Fe3O4. In this regard, the iron-iron oxide composition can be a mixture of Fe, FeO, Fe2O3, and Fe3O4.

[0172] In other embodiments, the iron-iron oxide composition further comprises a carbohydrate. In some embodiments, the carbohydrate content is from about 2 wt% to about 6 wt% relative to the iron-iron oxide composition. In other embodiments, the carbohydrate content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt% relative to the iron-iron oxide composition. In some embodiments, the carbohydrate content is from about 2 wt% to about 20 wt% relative to the iron-iron oxide composition.

[0173] The carbohydrate can be selected from monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Examples of carbohydrates are, but are not limited to, glucose, galactose, fructose, xylose, sucrose, lactose, maltose, trehalose, sorbitol, mannitol, maltodextrin, raffinose, stachyose, fructooligosaccharide, amylose, amylopectin, modified starch, glycogen, dextran, chitosan, glycosaminoglycan, alginate, ulvan, arabic gum, gellan gum, cellulose, hemicellulose, ethyl cellulose, methyl cellulose, pectin, hydrocolloid, and combinations thereof.

[0174] In some embodiments, the iron-iron oxide composition comprises iron, Fe3O4, and a carbohydrate. In some embodiments, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the carbohydrate content is from about 3 wt% to about 5 wt% relative to the iron-iron oxide composition.

[0175] In other embodiments, the iron-iron oxide composition further comprises an amino acid. In some embodiments, the amino acid content is from about 2 wt% to about 6 wt% relative to the iron-iron oxide composition. In other embodiments, the amino acid content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt% relative to the iron-iron oxide composition.

[0176] In the context of this specification, the term "amino acid" is defined as having at least one primary, secondary, tertiary, or quaternary amino group, and at least one acid group, where the acid group can be a carboxylic acid, sulfonic acid, or phosphonic acid, or a mixture thereof. Relative to the acid group, the amino group can be "α", "β", "γ"... up to "ω". The backbone of the "amino acid" can be substituted by one or more groups selected from halogen, hydroxyl, guanidyl, heterocyclic groups. Thus, the term "amino acid" also includes within its scope glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, etc. (L) and (D) forms of amino acids are included within the scope of the present disclosure.

[0177] In some embodiments, the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the carbohydrate content is from about 3 wt% to about 5 wt%.

[0178] In other embodiments, the iron-iron oxide composition further comprises an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, relative to the iron-iron oxide composition, the carbohydrate or its mixture content is from about 2 wt% to about 6 wt%. In other embodiments, relative to the iron-iron oxide composition, the carbohydrate or its mixture content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt%. For example, a mixture of methylcellulose and zein can be used.

[0179] In some embodiments, the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or its mixture content is from about 3 wt% to about 5 wt%.

[0180] In some embodiments, the iron-iron oxide composition is provided in the form of a powder having a particle size of from about 1 μm to about 100 μm. In some embodiments, the particle size of the iron-iron oxide composition is from about 1 μm to about 800 μm. In this regard, the iron-iron oxide can be micron-sized particles. In other embodiments, the particle size is from about 1 μm to about 700 μm, from about 1 μm to about 600 μm, from about 1 μm to about 500 μm, from about 1 μm to about 400 μm, from about 1 μm to about 300 μm, from about 1 μm to about 200 μm, from about 1 μm to about 100 μm, from about 1 μm to about 90 μm, from about 1 μm to about 80 μm, from about 1 μm to about 70 μm, from about 1 μm to about 60 μm, from about 1 μm to about 50 μm, from about 1 μm to about 40 μm, from about 1 μm to about 30 μm, or from about 10 μm to about 40 μm.

[0181] In some embodiments, the iron-iron oxide is a plurality of micron-sized particles. For example, the particles can have an iron core, which can be encapsulated by a shell. In some embodiments, the shell comprises an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, the shell comprises an amino acid. In some embodiments, the shell comprises a carbohydrate.

[0182] Amino acids can be used as encapsulating materials. In such instances, the amino acids can be polymerized into peptides. The peptides can also be used as encapsulating materials. These are also included in the definition of "amino acids". For example, zein can be used.

[0183] Similar to carbohydrates, when monosaccharides and / or disaccharides are used, these sugars can be polymerized during the encapsulation process. Long-chain biopolymers can be produced, which form a shell around the particles. Thus, monosaccharides, disaccharides, oligosaccharides, and polysaccharides are all included in the definition of "carbohydrates". For example, cyclodextrin can be used.

[0184] In some embodiments, the iron-iron oxide composition is a plurality of iron core-shell micron-sized particles, wherein the core comprises Fe and the shell comprises an amino acid. In some embodiments, the iron-iron oxide composition is a plurality of iron core-shell micron-sized particles, wherein the core comprises Fe, the shell comprises an amino acid, and the interface between the core and the shell comprises iron oxide. In other embodiments, the shell comprises an amino acid and iron oxide. In some embodiments, the iron oxide is Fe3O4. In some embodiments, the amino acid is selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, or a combination thereof.

[0185] Advantageously, when the iron particles are encapsulated by a shell, the iron core can be protected by the encapsulating shell material containing amino acids and / or carbohydrates. This can further delay the formation of iron oxides and thus the generation of ROS until it is used in the face mask. This prevents or reduces the over-oxidation of the iron particles, resulting in the face mask having a longer shelf life and / or generating more persistent ROS over a longer period of time. In addition, the amino acid and / or carbohydrate encapsulating material can change the electric potential of the iron core and alter the redox reaction pathway. For example, the generated iron oxide can form an interfacial layer between the shell and the iron core. This enables the generation and release of ROS to be controlled. In this way, the shell on the iron particles controls the oxidation rate of the iron, allowing for the continuous release of ROS, which is sufficient to achieve antibacterial and / or antiviral effects. This improves its applicability for a variety of uses and allows for additional cleaning. A further advantage is that due to the use of natural compounds such as biopolymers to encapsulate the iron particles, the biodegradability of the biopolymer causes the shell to decompose over time. For example, the shell decomposes over time after multiple cleanings. This provides additional antibacterial and / or antiviral persistence effects as the inner iron core, which was previously more difficult to reach, can now be more easily accessed.

[0186] In some embodiments, the thickness of the shell is from about 50 nm to about 400 nm. In other embodiments, the thickness is from about 50 nm to 350 nm, from about 50 nm to about 300 nm, from about 100 nm to about 300 nm, from about 150 nm to about 300 nm, or from about 200 nm to about 300 nm.

[0187] The shell can also contain iron. In this regard, in some embodiments, the shell contains iron and amino acids, carbohydrates, or a mixture thereof. Advantageously, due to the iron being closer to the surface of the particle, the presence of iron in the shell can "kick-start" the oxidation of iron to iron oxide. In this sense, the initial burst of ROS provided by the face mask can provide protection to the user upon first use of the face mask and before sufficient water is provided to the iron core as moisture.

[0188] In some embodiments, the iron-iron oxide composition is a plurality of iron core-shell micron-sized particles, where the core contains Fe and the shell contains Fe and amino acids. In some embodiments, the iron-iron oxide composition is a plurality of iron core-shell micron-sized particles, where the core contains Fe, the shell contains Fe and amino acids, and the interface between the core and the shell contains iron oxide. In some embodiments, the iron oxide is Fe3O4. In some embodiments, the amino acids are selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, or a combination thereof.

[0189] Advantageously, the amino acid-containing shell enables the iron-iron oxide composition to be better retained on the fabric surface. In this regard, the composite fabric can be washed multiple times and still retain its desired functionality.

[0190] As used herein, a "porous" material refers to a material containing pores (voids). The skeletal portion of the material is typically referred to as the "matrix" or "framework". The pores are usually filled with a fluid (liquid or gas). The skeletal material is typically solid or foamed. In this document, a porous fabric is a "breathable" fabric because it allows air to pass freely through. This may be because the fabric has a loose woven structure or can be a non-woven structure but allows fluid absorption. Examples of porous fabrics can be cotton, wool, and silk. In contrast, a non-porous material hinders fluid absorption: air cannot pass freely through a tightly bonded non-porous material; plastics used for fluid or food containers are completely non-porous. The most common characteristic of a porous medium is its porosity.

[0191] The fabric porosity can be defined as the ratio of the non-solid volume (voids) to the total volume of the fabric, and the volume fraction of the solid material is defined as the ratio of the solid fiber material to the total volume of the fabric. While the fiber density is only the weight of the fiber solids in a given volume (i.e., without other materials), the porosity can be calculated as follows using the bulk density and fiber density of the fabric:

[0192]

[0193]

[0194] where p is the fabric porosity (%), φ is the volume fraction of the solid material (%), ρ 织物 (kg / m 3 ) is the bulk density of the fabric, and ρ 纤维 (kg / m 3 ) is the fiber density.

[0195] In some embodiments, the porosity of the porous fabric is about 95%, about 90%, about 85%, about 80%, about 75%, about 70%, about 65%, or about 60%.

[0196] In some embodiments, the porous fabric of the composite material is a knitted porous fabric. A knitted fabric is a textile fabric formed by knitting. The properties of knitted fabrics differ from those of woven fabrics in that they are softer and easier to make into smaller pieces. In some embodiments, the porous fabric of the composite material is a woven porous fabric. A woven fabric is any textile fabric formed by interlacing. Woven fabrics are typically manufactured on a loom and are woven from many yarns on the warp and weft. Technically, a woven fabric refers to any fabric formed by interlacing two or more yarns at right angles to each other.

[0197] In some embodiments, the knitted porous fabric is selected from plain knitted fabric, double jersey fabric, rib fabric, sweatshirt fleece fabric, interlock fabric, spandex fabric, double knit fabric, polar fleece fabric, and terry knitted fabric.

[0198] In some embodiments, the porous fabric of the composite material is a fabric comprising cotton and spandex. In some embodiments, the cotton is about 95 wt%, about 90 wt%, about 85 wt%, about 80 wt%, about 75 wt%, about 70 wt%, about 65 wt%, or about 60 wt% relative to the fabric. In other embodiments, the spandex is about 10 wt% relative to the fabric. In other embodiments, the spandex is about 5 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, or about 40 wt% relative to the fabric.

[0199] In some embodiments, the porous fabric of the composite material is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0200] Spandex, Lycra, or elastane is a synthetic fiber known for its excellent elasticity. It is a polyether-polyurea copolymer.

[0201] Advantageously, the use of spandex makes it easy to form the composite material. As disclosed herein, when forming the composite material, it is slightly stretched. It has been found that stretching promotes the impregnation of the iron-iron oxide composition into the fabric. In addition, the use of spandex makes it easy to cut the composite material for forming the face mask.

[0202] The waterproof coating can provide a lotus effect on the composite material, thereby providing a lotus effect on the face mask made of the composite material. In nature, the lotus leaf has an unprecedented ability to roll water droplets off its surface due to "superhydrophobicity". The fine structure of the leaf surface is produced by the coexistence of micron-scale papillae (10 μm to 20 μm in height, 10 μm to 15 μm in width), nano-scale hair-like structures, and a hydrophobic waxy coating covering everywhere. Physically, this fine structure minimizes the adhesion of liquid droplets to the leaf surface. For this reason, the inventors have developed several fabric finishes to mimic the "lotus effect" and achieve high waterproofness and "self-cleaning" properties. When water droplets roll off this highly waterproof surface, dirty particles and other impurities on the surface will "flow downstream". The chemical composition is as follows:

[0203] C6 Chemical Composition – PFHA (Perfluorohexanoic Acid; C6) has a 6-carbon atom backbone and is considered 40 times less bioaccumulative than perfluorooctanoic acid (PFOA; C8; 8-carbon counterpart). However, it is also less effective, so more chemicals must be used to achieve the same effect. In addition, the formulation also contains a small amount of C8 molecules. Currently, C6 technology is most prevalent in the textile industry, although more and more sustainability-conscious brands are phasing out the use of such chemicals in their products.

[0204] Fluorine-free Chemical Composition: While products that do not contain PFOA and perfluorooctane sulfonate (PFOS) claim to be fluorine-free DWR products, there are also products involving completely different chemical compositions that are already on the market or are being trialed. Paraffin (and other hydrocarbon-based solutions), silica nanoparticles, and silanes (such as alkyltrialkoxysilanes) are some of the tested examples.

[0205] Advantageously, the waterproof coating makes the composite washable and does not lose its antibacterial and antiviral properties. In this regard, the coating prevents or at least reduces the loss of the iron-iron oxide composition in the fabric. More advantageously, the composite can be used as an outer layer (in contact with the environment) and accordingly reduces the number of layers required to form a face mask, but at the same time maintains the same, if not better, level of protection.

[0206] In addition, the waterproof coating prevents or reduces the oxidation of iron particles during the washing process. As described herein, iron is oxidized to iron oxide in the presence of water and oxygen. Advantageously, it has been found that, by synergistically acting with the shell on the iron particles, the waterproof coating can further provide protection to the iron-iron oxide composition. In this regard, the release of ROS can be better controlled.

[0207] In some embodiments, the waterproof coating is selected from perfluorobutane sulfonic acid, perfluorooctanoic acid, perfluorohexanoic acid, Scotchgard, perfluorooctane sulfonate, paraffin (and other hydrocarbon-based solutions), silica nanoparticles, and silanes (such as alkyltrialkoxysilanes).

[0208] In some embodiments, the waterproof coating is located on one side of the porous fabric. When the coating is applied to one side of the porous fabric, the coating can be on the side impregnated with the iron-iron oxide composition. In some embodiments, the waterproof coating is located on at least one side of the porous fabric. In other embodiments, the waterproof coating is located on both sides of the porous fabric.

[0209] In some embodiments, the thickness of the waterproof coating is from about 1 μm to about 1000 μm. In other embodiments, the thickness is from about 1 μm to about 900 μm, from about 1 μm to about 800 μm, from about 1 μm to about 700 μm, from about 1 μm to about 600 μm, from about 1 μm to about 500 μm, from about 1 μm to about 400 μm, from about 1 μm to about 300 μm, from about 1 μm to about 200 μm, or from about 1 μm to about 100 μm. In other embodiments, the thickness is from about 10 μm to about 1000 μm, from about 10 μm to about 900 μm, from about 10 μm to about 800 μm, from about 10 μm to about 700 μm, from about 10 μm to about 600 μm, from about 10 μm to about 500 μm, from about 10 μm to about 400 μm, from about 10 μm to about 300 μm, from about 10 μm to about 200 μm, or from about 10 μm to about 100 μm.

[0210] In some embodiments, after 20 washes, at least 70% of the iron-iron oxide composition remains in the composite material. In some embodiments, at least 75%, at least 80%, at least 85%, at least 90% or at least 95% of the iron-iron oxide composition remains. In other embodiments, the composite material can be washed at least 10 times, at least 15 times, at least 20 times, at least 25 times or at least 30 times.

[0211] As described below, carbohydrates, amino acids, or mixtures thereof can be provided by the cashew seed coat extract. Other components such as proteins, sugars, tannic acid and phenolic compounds can also be present in the cashew seed coat extract and can form part of the iron-iron oxide composition. In addition, in some embodiments, the composite material further comprises a second coating formed from an extract obtained from the cashew seed coat. This can be a cashew seed coat extract other than that present in the iron-iron oxide composition.

[0212] Advantageously, the cashew seed coat extract coating also provides an additional protective layer for the iron-iron oxide composition. The cashew seed coat extract contains a variety of polyphenols, including tannic acid. Tannic acid is a water-soluble reddish-brown molecule. Due to its high antioxidant and anti-inflammatory activities, tannic acid can have anti-cancer and anti-mutagenic properties. The antibacterial properties of tannic acid can also effectively inhibit the growth of a variety of fungi, yeasts, Gram-positive bacteria such as Staphylococcus aureus and viruses (Norovirus, Influenza A virus and Papillomavirus) through the antibacterial and antiviral mechanisms of the present disclosure.

[0213] Advantageously, since cashew nuts are a major crop in the world and the bitter and astringent taste of the cashew nut testa (reddish-brown skin) causes the testa to be generally discarded as waste, the testa can be collected and extracted at low cost. The cashew nut testa extract has antibacterial properties against Gram-negative bacteria, Escherichia coli, and Gram-positive bacteria, Staphylococcus aureus. It also has anti-cancer properties against human liver cancer cells, HEPG2. It is advantageous to synthesize antimicrobial compositions using these waste materials because of their low production cost and environmental friendliness.

[0214] In some embodiments, the thickness of the cashew nut testa extract coating is from about 10 μm to about 1000 μm. In other embodiments, the thickness is from about 10 μm to about 900 μm, from about 10 μm to about 800 μm, from about 10 μm to about 700 μm, from about 10 μm to about 600 μm, from about 10 μm to about 500 μm, from about 10 μm to about 400 μm, from about 10 μm to about 300 μm, from about 10 μm to about 200 μm, or from about 10 μm to about 100 μm.

[0215] In some embodiments, the cashew nut testa extract coating coats one side of the composite material. In other embodiments, the cashew nut testa extract coating coats at least one side of the composite material. In other embodiments, the cashew nut testa extract coating coats both sides of the composite material.

[0216] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 1 wt% relative to the composite material; wherein the thickness of the waterproof coating is from about 10 μm to about 500 μm.

[0217] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the thickness of the waterproof coating is from about 10 μm to about 500 μm; and wherein the waterproof coating is selected from perfluorooctanoic acid, perfluorohexanoic acid, silica nanoparticles, and silanes (such as alkyltrialkoxysilanes).

[0218] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the thickness of the waterproof coating is from about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0219] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; wherein the waterproof coating is selected from perfluorooctanoic acid, perfluorohexanoic acid, silica nanoparticles, and silanes (such as alkyltrialkoxysilanes); and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0220] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and a carbohydrate; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the carbohydrate content is about 3 wt% to about 5 wt%; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0221] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid content is about 3 wt% to about 5 wt%; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0222] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or mixture thereof content is about 3 wt% to about 5 wt%; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0223] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or mixture thereof content is about 3 wt% to about 5 wt%; wherein the iron-iron oxide composition is provided in the form of a powder having a particle size of about 1 μm to about 100 μm; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0224] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or mixture thereof content is about 3 wt% to about 5 wt%; wherein the iron-iron oxide composition is provided in the form of a powder having a particle size of about 1 μm to about 100 μm; wherein the particle comprises an iron core, a shell, and an interface between the core and the shell, wherein the shell comprises an amino acid, a carbohydrate, or a mixture thereof, and wherein the interface comprises iron oxide; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0225] In some embodiments, the composite material comprises: a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, wherein the iron-iron oxide composition is impregnated at about 0.1 wt% to about 5 wt% relative to the composite material; wherein the iron-iron oxide composition comprises iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof; relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or mixture thereof content is about 3 wt% to about 5 wt%; wherein the iron-iron oxide composition is provided in the form of a powder having a particle size of about 1 μm to about 100 μm; wherein the particles comprise an iron core, a shell, and an interface between the core and the shell, wherein the shell comprises an amino acid, a carbohydrate, or a mixture thereof, and wherein the interface comprises iron oxide; wherein the thickness of the shell is about 50 nm to about 400 nm; wherein the thickness of the waterproof coating is about 10 μm to about 500 μm; and wherein the porous fabric is a fabric comprising 90 wt% cotton and 10 wt% spandex.

[0226] Reference is now made to Figure 9 and Figure 10 , which shows another example of a face mask 400. The face mask 400 is substantially the same in form as the face mask 100, although the face mask 400 has a different inner layer 430. In particular, the inner layer 430 of the face mask 400 may be provided with a pocket or sleeve 431 for receiving a replaceable filter layer 420 in the manner Figure 10 shown. For example, the sleeve 431 may be provided by sewing or otherwise securing the inner layer 430 to the remaining layers of the face covering portion 410 of the face mask 400 at or near one end of the inner layer 430 to form an end 434 of the sleeve 431. The other end of the inner layer 430 may remain unconnected, or a cut 432 may be formed in the inner layer 430 to leave an opening of the sleeve 431 for inserting the filter layer 420.

[0227] As described above, the filter layer 420 may have physical and chemical properties similar to or the same as those of the filter layer 320 of the face mask 100.

[0228] Advantageously, by providing the sleeve 431 on the inner layer 430, the filter layer 420 can be removed before cleaning or replaced with another similar filter layer at the end of its useful life (e.g., every 100 hours to ensure that the face mask 400 continues to have the desired antiviral effect).

[0229] The present invention also provides a face mask comprising:

[0230] a body sized to at least cover a user's nose and mouth when the body is in a use position on the user's face; wherein the body comprises:

[0231] a) An outer composite fabric layer;

[0232] b) An inner fabric layer adjacent to the outer composite fabric layer such that the inner fabric layer is in a use position on the user's face; and

[0233] c) A filter layer sandwiched between the outer composite fabric layer and the inner fabric layer;

[0234] wherein the outer composite fabric layer is the composite material disclosed herein.

[0235] The face mask is designed to be worn on the wearer's face and includes a face mask body and a pair of ear straps. The face mask is designed for multiple uses (at least once or several times) or is of a reusable type that can be reused by washing.

[0236] The face mask body covers at least the wearer's mouth and nose (nostrils). The pair of ear straps extend from both sides of the face mask body and are designed to hook around the wearer's ears. The ear straps are preferably made of an elastic material to prevent excessive load on the ears. In addition, the face mask body is preferably made of a soft and comfortable-to-wear material and has a lower stretchability than the ear straps, so that when the face mask is worn on the face, the face mask body maintains its shape. The face mask body can be planar or three-dimensional. In the case of a three-dimensional face mask, the face mask body must be in a three-dimensional shape at least when the face mask is worn. (For example, the face mask body can be designed to be in a three-dimensional form when the face mask is worn and can be folded into a planar form in a preset manner when the face mask is not worn.) Therefore, the face mask body can be designed to be three-dimensional both when the face mask is worn and when it is not worn.

[0237] The face mask can not only filter out 0.3μm virus-like particles but also kill viruses such as influenza. Most commercially available face masks claiming antiviral properties can only be used once. In contrast, the face mask of the present invention is a fabric face mask that allows washing up to 30 times and still maintains its antiviral and filtering properties. The face mask is a more sustainable product than commercially available disposable face masks.

[0238] In some embodiments, the face mask includes:

[0239] A body sized to cover at least the user's nose and mouth when the body is in a use position on the user's face; wherein the body includes:

[0240] a) An outer composite fabric layer;

[0241] b) An inner fabric layer adjacent to the outer composite fabric layer such that the inner fabric layer is in a use position on the user's face; and

[0242] c) A filter layer sandwiched between the outer composite fabric layer and the inner fabric layer;

[0243] Wherein the outer composite fabric layer is the composite material disclosed herein;

[0244] Wherein the inner fabric layer is a quick-drying fabric selected from nylon, polyester, merino wool, cotton, and cotton and polyester blended fabrics;

[0245] Wherein the filter layer is melt-blown polypropylene.

[0246] In some embodiments, the face mask comprises:

[0247] A body sized to at least cover the user's nose and mouth when the body is in a use position on the user's face; wherein the body comprises:

[0248] a) An outer composite fabric layer;

[0249] b) An inner fabric layer adjacent to the outer composite fabric layer such that the inner fabric layer is in a use position on the user's face; and

[0250] c) A filter layer sandwiched between the outer composite fabric layer and the inner fabric layer;

[0251] Wherein the outer composite fabric layer is the composite material disclosed herein;

[0252] Wherein the inner fabric layer is a quick-drying fabric selected from nylon, polyester, merino wool, cotton, and cotton and polyester blended fabrics;

[0253] Wherein the filter layer is melt-blown polypropylene comprising charcoal, bamboo fiber, or nanomaterials.

[0254] In some embodiments, the face mask comprises:

[0255] A body sized to at least cover the user's nose and mouth when the body is in a use position on the user's face; wherein the body comprises:

[0256] a) An outer composite fabric layer;

[0257] b) An inner fabric layer adjacent to the outer composite fabric layer such that the inner fabric layer is in a use position on the user's face; and

[0258] c) A filter layer sandwiched between the outer composite fabric layer and the inner fabric layer;

[0259] Wherein the outer composite fabric layer is the composite material of the present disclosure;

[0260] Wherein the inner fabric layer is a quick-drying fabric selected from nylon, polyester, merino wool, cotton, and cotton and polyester blended fabrics;

[0261] Wherein the filter layer is melt-blown polypropylene comprising charcoal, bamboo fiber, or nanomaterials; and

[0262] Wherein the filter layer is capable of filtering particles with a particle size greater than 0.3 μm and has a filtration efficiency of at least about 80%.

[0263] The present invention also provides a method for manufacturing a composite material, which includes:

[0264] a) impregnating a porous fabric with an iron-iron oxide composition; and

[0265] b) applying a waterproof coating on at least one side of the porous fabric to form a composite material,

[0266] wherein the iron-iron oxide composition is present in an amount of about 0.1 wt% to about 5 wt% relative to the composite material;

[0267] wherein the thickness of the waterproof coating is about 10 μm to about 500 μm.

[0268] In some embodiments, the impregnation step (step a) is completed using a padding mangle. A padding mangle is a mechanical laundry device consisting of two rollers housed in a sturdy frame, connected by gears, and used to press or flatten the fabric.

[0269] In some embodiments, the method further includes a step after step (a) of curing the porous fabric with the iron-iron oxide composition. The curing step can be carried out at a temperature above 100 °C or about 120 °C.

[0270] In some embodiments, the coating step (step b) is completed using a stentering machine. A stentering machine is an oven specifically designed for fabric processing and is used to dry and heat-treat the fabric after wet processing.

[0271] In some embodiments, the method further includes applying a second coating formed from an extract obtained from cashew nut shells.

[0272] In some embodiments, the thickness of the cashew nut shell extract coating is about 10 μm to about 500 μm.

[0273] The present invention also provides a method for manufacturing a face mask, which includes:

[0274] a) impregnating a porous fabric with an iron-iron oxide composition;

[0275] b) coating the porous fabric with a waterproof coating on at least one side of the porous fabric to form an outer composite fabric layer; and

[0276] c) stitching together the outer composite fabric layer, the inner fabric layer, and the filter layer to form a body, with the inner fabric layer adjacent to the outer composite fabric layer such that the inner fabric layer is in the usage position on the user's face and the filter layer is sandwiched between the outer composite fabric layer and the inner fabric layer, and the size of the body is designed to cover at least the user's nose and mouth when it is in the usage position on the user's face,

[0277] wherein the iron-iron oxide composition is present in an amount of from about 0.1 wt% to about 5 wt% relative to the composite fabric layer;

[0278] wherein the thickness of the waterproof coating is from about 10 μm to about 500 μm.

[0279] In some embodiments, the outer composite fabric layer and the filter layer are fused together. Fusing can be carried out using a heat transfer fusing machine.

[0280] In some embodiments, the method further comprises forming the body into a three-dimensional form. In other embodiments, the body is formed into a shape having a concave profile.

[0281] In other embodiments, the method further comprises stitching two loops at opposite ends of the body to form a pair of ear loops.

[0282] In some embodiments, the method further comprises a step before step (c) of die-cutting the shape of the face mask from the outer composite fabric layer, the inner fabric layer, and the filter layer.

[0283] The inventors have found that natural product extracts can be combined synergistically (or at least additively) to particular advantage. In particular, the inventors have found that cashew nut shell extract has antimicrobial efficacy. When formulated into the compositions disclosed herein, the antimicrobial efficacy can be synergistically enhanced. It is contemplated that compositions having antimicrobial (antibacterial and / or antiviral) properties are advantageous when applied as disinfectants or used on surfaces or in textiles.

[0284] The inventors have also found that if the cashew nut shell is subjected to certain processing steps, the antimicrobial efficacy of the cashew nut shell extract can be increased. It is believed that by these steps, the amount of the active ingredient extracted is increased without adversely affecting its antimicrobial function. In addition, the amount of impurities extracted simultaneously is not further increased correspondingly and is also reduced. This is advantageous because when formulated into a product, it gives the consumer a good appearance and feel. The increase in the proportion of the active ingredient also reduces the effect of impurities "blocking" the antimicrobial efficacy of the active ingredient compared to the impurities.

[0285] The present invention provides a method for synthesizing a cashew nut shell extract composition, comprising:

[0286] a) dispersing the cashew nut shell in a solvent to form a dispersion;

[0287] b) stirring the dispersion under heating and / or sonication to extract phenolic compounds; and

[0288] c) filtering the dispersion to obtain the cashew nut shell extract composition;

[0289] wherein the cashew seed coat extract composition comprises phenolic compounds; and

[0290] wherein the cashew seed coat extract composition comprises proteins, amino acids, sugars, or combinations thereof.

[0291] Advantageously, it has been found that the stirring step (b) increases the extraction of the active ingredient. It has been found that the amount of the active ingredient using the method of the present disclosure is at least 0.5 times more than that of the comparative example (shown below).

[0292] In some embodiments, the stirring step is carried out at a temperature of about 40°C to about 100°C. In other embodiments, the temperature is about 80°C.

[0293] In other embodiments, the stirring step under sonication is the ultrasonic disruption method. Sonication can be carried out at an elevated temperature, such as from about 40°C to about 95°C. Advantageously, it has been found that sonication is more effective than heat treatment in extracting the active ingredient.

[0294] In some embodiments, the stirring step is carried out for about 1 h to about 24 h.

[0295] In some embodiments, the solvent is an aqueous medium.

[0296] Advantageously, since water can be used, it is easy to apply the composition to a surface or textile to obtain an antimicrobial effect. The use of water also makes this method easy to scale up and green.

[0297] As used herein, the terms "aqueous solution" or "aqueous medium" refer to a water-based solvent or solvent system consisting mainly of water. Such a solvent can be polar or non-polar, and / or protic or aprotic. A solvent system refers to a combination of solvents that ultimately form a single phase. The'solvent' and'solvent system' can include, but are not limited to, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, 1,4-dioxane, chloroform, diethyl ether, dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, formic acid, butanol, isopropanol, propanol, ethanol, methanol, acetic acid, ethylene glycol, diethylene glycol, or water. The water-based solvent or solvent system can also include dissolved ions, salts, and molecules, such as amino acids, proteins, sugars, and phospholipids. These salts can be, but are not limited to, sodium chloride, potassium chloride, ammonium acetate, magnesium acetate, magnesium chloride, magnesium sulfate, potassium acetate, potassium chloride, sodium acetate, sodium citrate, zinc chloride, HEPES-Na, calcium chloride, iron nitrate, sodium bicarbonate, potassium phosphate, and sodium phosphate. Thus, biological fluids, physiological solutions, and culture media also fall within this definition. In most embodiments, the aqueous solution is water. In some embodiments, the aqueous solution is deionized water. In some embodiments, the aqueous solution is microporous water.

[0298] An aqueous solution is advantageously used in the present disclosure. In particular, water is used. By heating while controlling the pressure and temperature, water can be evaporated or sublimated from the aqueous solution, making it the greenest, ideally harmless and non-toxic solvent for use.

[0299] The cashew seed coat extract contains various polyphenols, including tannic acid. Tannic acid is a water-soluble, reddish-brown molecule. It is believed that tannic acid and phenolic compounds in general can have antimicrobial effects by binding to bacteria, disrupting the integrity of the bacterial cell membrane, and disrupting various functions within the bacterial cell.

[0300] One hypothesis is that various intracellular functions change due to the change in cell wall rigidity and loss of integrity caused by the hydrogen bonding of phenolic compounds to enzymes or due to different interactions with the cell membrane. This can lead to irreversible damage to the cytoplasmic membrane and the condensation of cell contents, and may even lead to the inhibition of intracellular enzymes. For example, condensed phenylpropanoid compounds - tannins may damage the cell membrane and even inactivate metabolism by binding to enzymes, while phenolic acids have been shown to disrupt the integrity of the cell membrane as they cause the leakage of essential components within the cell. Flavonoids may be linked to soluble proteins located outside the cell and in the bacterial cell wall, thus promoting the formation of complexes. Flavonoids may also act by inhibiting energy metabolism and DNA synthesis, thereby affecting the synthesis of proteins and RNA. In the case of Gram-positive bacteria, changes in intracellular pH and interference with the energy (ATP) generation system have been reported.

[0301] In some embodiments, the composition comprises polyphenols or phenolic compounds such as tannins, catechins, epicatechins, epigallocatechin, and p-coumaric acid, gallic acid, or combinations thereof. These polyphenols have high antioxidant activity and exhibit high free radical scavenging activity. The compounds of phenolic compounds can be in any desired percentage or ratio. The phenolic compounds used herein refer to compounds containing at least one aromatic ring linked to a hydroxyl group (-OH).

[0302] In some embodiments, the composition comprises proteins, amino acids, starches, carbohydrates, sugars, or combinations thereof.

[0303] As used interchangeably herein, "polypeptide", "peptide" and "protein" refer to any polymer of amino acid residues (dipeptide or polypeptide) linked by peptide bonds or modified peptide bonds, as well as variants and synthetic analogs thereof. Thus, these terms apply to amino acid polymers in which one or more amino acid residues are synthetic, non-naturally occurring amino acids, such as chemical analogs of the corresponding naturally occurring amino acids, as well as naturally occurring amino acid polymers. The polypeptides of the present invention include, but are not limited to, naturally purified products, products of chemical synthesis processes, and products produced by recombinant techniques from prokaryotic or eukaryotic hosts, including, for example, bacteria, yeast, higher plants, insects, and mammalian cells. The polypeptides of the present invention may contain non-peptide components, such as carbohydrate groups. Carbohydrates and other non-peptide substituents may be added to the polypeptide by the cells producing the polypeptide and will vary with the type of cell. For recombinantly produced polypeptides, the nature and extent of the modifications are largely determined by the post-translational modification capabilities of the particular host cell and the modification signals present in the amino acid sequence of the polypeptide. For example, glycosylation patterns vary between different types of host cells. Polypeptides are defined herein according to their amino acid backbone structure; substituents such as carbohydrate groups are generally not specified but may still be present. In addition, the polypeptides of the present invention may also include an initially modified methionine residue, in some cases as a result of a host-mediated process. Proteins may exist as monomeric or multimeric proteins, such as dimers (homo- or heterodimers) or trimers.

[0304] As used herein, carbohydrates are biomolecules composed of carbon (C), hydrogen (H), and oxygen (O) atoms, usually with a hydrogen to oxygen atom ratio of 2:1 (as in water), and thus having the empirical formula C m (H2O) n (where m may differ from n). However, not all carbohydrates conform to this precise stoichiometric definition (e.g., uronic acids, deoxysugars such as fucose). The term is synonymous with saccharides, which include sugars, starches, and celluloses. Saccharides are divided into four chemical groups: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides are the smallest (lower molecular weight) carbohydrates and are commonly referred to as sugars. Examples of carbohydrates or sugars are monosaccharides such as glucose, galactose, fructose, xylose; disaccharides such as sucrose, lactose, maltose, trehalose, polyols such as sorbitol, mannitol; oligosaccharides such as maltooligosaccharides (maltodextrin), raffinose, stachyose, fructooligosaccharides; polysaccharides such as starch (amylose, amylopectin, modified starch) and non-starch polysaccharides (glycogen, cellulose, hemicellulose, pectin, hydrocolloids).

[0305] In some embodiments, the weight ratio of the phenolic compound to the protein is from about 1:100 to about 100:1.

[0306] In some embodiments, the weight ratio of the phenolic compound to the sugar is from about 1:100 to about 100:1.

[0307] In some embodiments, filtration step (c) includes passing the dispersion through microfiltration. The pore size of the microfiltration is from about 0.1 μm to about 10 μm.

[0308] Preferably, the pore size of the microfiltration is from about 0.1 μm to about 10 μm. Alternatively, filtration step (c) may include microfiltration, ultrafiltration, reverse osmosis, or a combination thereof.

[0309] In some embodiments, the method further includes a step of cleaning the cashew seed coat before step (a). The cleaning step can be carried out in a solvent selected from an aqueous medium, an alcohol, or N,N-dimethylformamide.

[0310] Advantageously, the cleaning step can wash away impurities such as proteins, amino acids, and sugars. This gives the composition a "cleaner" and greener sense of consumption.

[0311] In some embodiments, the method further includes a step of removing the solvent after step (c). In some embodiments, the solvent removal step is freeze-drying.

[0312] Advantageously, freeze-drying makes the composition easy to transport and store. It can also increase the shelf life of the composition.

[0313] In some embodiments, the method further includes a step of adding an excipient. The excipient can be a stabilizer, a dispersant, a colorant, or a combination thereof.

[0314] "Excipient" is an inactive substance used as a carrier or vehicle for an active substance, including any and all solvents, dispersion media, inert diluents or other liquid carriers, dispersants or suspending agents, granulating agents, surfactants, disintegrants, isotonic agents, thickening or emulsifying agents, preservatives, binders, lubricants, buffers, oils, etc. Various excipients for formulating compositions and known techniques for their preparation are disclosed in G.A.R. Remington: The Science and Practice of Pharmacy, 21st ed. (2006), Lippincott Williams & Wilkins. The use thereof is contemplated within the scope of the present invention unless any conventional excipient is incompatible with the substance or its derivatives, such as producing any undesirable biological effects or interacting in a harmful manner with any other component of the pharmaceutical composition.

[0315] According to the judgment of the formulation designer, excipients such as colorants, coating agents, preservatives, and fragrances may be present in the composition. Examples of excipients are colloidal silica, hydroxypropyl methylcellulose, vitamin A, vitamin E, vitamin C, palmitoyl retinyl ester, selenium, sodium metabisulfite, propyl gallate, cysteine, methionine, citric acid, sodium citrate, methyl paraben, propyl paraben, benzalkonium chloride, and lanolin.

[0316] Advantageously, lyophilization makes the composition easy to transport and store. It can also extend the shelf life of the composition.

[0317] The present invention also provides a cashew seed coat extract composition, which comprises:

[0318] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin gallate, p-coumaric acid, gallic acid, or combinations thereof; and

[0319] b) proteins, amino acids, sugars, or combinations thereof.

[0320] Combination of cashew seed coat extract with iron and / or iron oxide particles

[0321] Although the above-mentioned cashew seed coat extract composition is advantageous, the inventors have found that it can be further improved. For example, the retention time of the extract on the surface can be further increased. The compounds of the extract in the comparative example are also easily degraded, so the antimicrobial efficacy decreases rapidly. It has also been further found that when the comparative example is applied to a porous membrane, the compounds of the extract in the comparative example are only retained at the interface and do not penetrate. Therefore, the antimicrobial effect is not persistent.

[0322] The development of microbial infections and antimicrobial drug resistance has received attention as one of the most important key issues facing public health and safety. The invention of a clean antimicrobial surface with long-term stability and activity has great application prospects, and its applications almost cover all aspects of our daily life, such as medical devices, hospital surfaces, textiles, packaging, electrical appliances, marine antifouling, filters, and public surfaces. Inorganic antimicrobial materials, especially semiconductor antimicrobial materials, are not easily chemically contaminated and have long-term stability. Some metals or metal oxides, such as silver, zinc oxide, and titanium oxide particles, have been used as antimicrobial components in various products or antimicrobial surface coatings. However, these materials also have limitations, such as heavy metal pollution / toxicity (for silver-based materials). For ZnO and TiO2 materials, due to their dependence on light irradiation, their antimicrobial efficacy is low and their applications are limited. In addition, another problem with nanomaterials is the uncertainty of nanotoxicity.

[0323] In addition, contrary to the case when the cashew seed coat extract is added as a coating to fabrics, it was found that by incorporating the cashew seed coat extract during the synthesis of iron particles, the cashew seed coat extract can at least partially passivate the surface of the iron particles. This further enhances the stability of the iron particles and controls the release of ROS from the iron particles. More advantageously, by reacting the cashew seed coat extract with the iron particles and / or iron oxide precursors, in addition to being partially passivated by the cashew seed coat extract, the cashew shell extract also forms a partial shell covering the iron particles, enabling the release of ROS to be extended over a longer period of time.

[0324] To this end, the inventors found that by combining the cashew seed coat extract with iron particles and / or iron oxide particles, the antimicrobial efficacy can be further synergistically (or at least additively) enhanced. Advantageously, the inventors found that the iron-based antimicrobial material is non-toxic, highly active against microorganisms, very stable, and has long-term activity.

[0325] The iron particles can have a nanostructured protective shell covering the iron core. This shell is formed by the reaction of iron and the cashew seed coat extract under non-organic solvent conditions. The core-shell structure creates a special interface between the iron core and the iron complex shell, altering the electric potential and the redox reaction pathway of the iron core. For this reason, it is believed that this self-corrosion process can also occur on Fe / Fe e O3, Fe / Fe e O3 particles, and / or their combinations. The electrons generated by iron corrosion can be transferred to the conduction band (CB) of the iron oxide in an energy-favorable manner. The electrons in the CB are capable of reducing oxygen and generating ROS. The iron particles can generate different ROS, including superoxide, singlet oxygen, and hydroxyl radicals. In other words, electrons are contributed from iron to the iron oxide (CB) and reduce oxygen molecules to generate free radicals in an energy-favorable manner. The entire system does not rely on external stimuli, the ROS generation process can be manipulated, and it has long-term stability. Then the ROS will kill the bacteria and viruses in contact. The ROS killing mechanism of this material is similar to that of photocatalytic materials such as ZnO and TiO2, but since the iron / iron oxide particles are self-catalytic materials, it does not rely on light irradiation to generate ROS. The iron particles sacrifice their iron core to generate ROS. The new material designed based on this concept can replace organic disinfectants, preservatives, and antibiotics in a wide range of applications as a non-toxic and safe antimicrobial technology, especially playing a key role in controlling the spread of infectious diseases and antimicrobial resistance (AMR).

[0326] In some embodiments, the cashew seed coat extract is mixed with or reacted with iron particles and / or iron oxide particles. Advantageously, the mixing passivates at least in part the surface of the iron particles and / or iron oxide particles with components of the cashew seed coat extract. This places it in a very close position such that when “activated”, a shell can be formed and the ROS process can be initiated. Alternatively, a shell that releases ROS can be formed by reacting the cashew seed coat extract with iron particles and / or iron oxide particles (or their precursors).

[0327] The present invention also provides a method for synthesizing an iron-iron oxide composition, which comprises:

[0328] a) mixing a cashew seed coat extract with iron particles and / or iron oxide particles to obtain an iron-iron oxide composition;

[0329] wherein the cashew seed coat extract contains phenolic compounds;

[0330] wherein the cashew seed coat extract contains proteins, amino acids, sugars or combinations thereof; and

[0331] wherein the iron particles and / or iron oxide particles are at least partially passivated by the cashew seed coat extract.

[0332] As used herein, “particles” refers to micron-sized particles and / or nano-sized particles. Microparticles are particles having a size of 1 μm to 1000 μm. Nanoparticles are particles having a size of 1 nm to 1000 nm. The particles can be of any shape or morphology, such as spherical, rod-shaped or asymmetric.

[0333] Advantageously, it has been found that the physical combination of the cashew seed coat extract with iron particles and / or iron oxide particles acts synergistically (or at least additively) with each other, thereby increasing the antimicrobial effect. Without wishing to be bound by theory, it is believed that when the compounds in the cashew seed coat extract are allowed to passivate the iron / iron oxide particles, the aggregation and / or agglomeration of the iron / iron oxide particles can be reduced. In addition, with the improvement of particle stability, it has been found that when applied to a porous substrate or a textile, the composition can impregnate the surface of the porous substrate. This is contrary to the cashew seed coat extract alone or the iron / iron oxide particles alone, which are found to be present on the surface. Therefore, the retention time of the composition on the surface is increased, and accordingly the antimicrobial efficacy is improved.

[0334] At least when the phenolic compounds are adsorbed on the surface of the iron / iron oxide particles, it has been found that they are slightly protected from degradation, thereby ensuring a more persistent antimicrobial effect.

[0335] In some embodiments, the iron oxide particles are core-shell particles, where the core is a elemental iron core or an iron alloy core; and the shell is an iron oxide shell. In some embodiments, the iron particles and / or the iron oxide particles are iron-iron oxide particles. In some embodiments, the iron-iron oxide composition comprises iron, iron(II) oxide, and iron(III) oxide. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 90 wt%. In other embodiments, relative to the iron-iron oxide composition, the iron content is greater than 91 wt%, greater than 92 wt%, greater than 93 wt%, greater than 94 wt%, greater than 95 wt%, greater than 96 wt%, or greater than 97 wt%. In other embodiments, relative to the iron-iron oxide composition, the iron(II) oxide and iron(III) oxide content is less than 10 wt%. In other embodiments, relative to the iron-iron oxide composition, the iron(II) oxide and iron(III) oxide content is less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, or less than 3 wt%.

[0336] In some embodiments, the iron is elemental iron. In other embodiments, the iron(II) oxide is FeO. In other embodiments, the iron(II) oxide is Fe2O3. In other embodiments, the iron(II) oxide and iron(III) oxide is Fe3O4. In this regard, the iron-iron oxide composition can be a mixture of Fe, FeO, Fe2O3, and Fe3O4.

[0337] In other embodiments, the iron particles and / or the iron oxide particles further comprise a carbohydrate. In some embodiments, relative to the iron-iron oxide composition, the carbohydrate content is from about 2 wt% to about 6 wt%. In other embodiments, relative to the iron-iron oxide composition, the carbohydrate content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt%. In some embodiments, relative to the iron-iron oxide composition, the carbohydrate content is from about 2 wt% to about 20 wt%.

[0338] The carbohydrate can be selected from monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Examples of carbohydrates are, but not limited to, glucose, galactose, fructose, xylose, sucrose, lactose, maltose, trehalose, sorbitol, mannitol, maltodextrin, raffinose, stachyose, fructooligosaccharide, amylose, amylopectin, modified starch, glycogen, dextran, chitosan, glycosaminoglycan, alginate, ulvan, gum arabic, gellan gum, cellulose, hemicellulose, ethyl cellulose, methyl cellulose, pectin, hydrocolloid, and combinations thereof.

[0339] In some embodiments, the iron particles and / or iron oxide particles comprise iron, Fe3O4, and a carbohydrate. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the carbohydrate content is from about 3 wt% to about 5 wt%.

[0340] In other embodiments, the iron particles and / or iron oxide particles further comprise an amino acid. In some embodiments, relative to the iron-iron oxide composition, the amino acid content is from about 2 wt% to about 6 wt%. In other embodiments, relative to the iron-iron oxide composition, the amino acid content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt%.

[0341] In some embodiments, the iron particles and / or iron oxide particles comprise iron, Fe3O4, and an amino acid. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the carbohydrate content is from about 3 wt% to about 5 wt%.

[0342] In other embodiments, the iron particles and / or iron oxide particles further comprise an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, relative to the iron-iron oxide composition, the carbohydrate or mixture thereof content is from about 2 wt% to about 6 wt%. In other embodiments, relative to the iron-iron oxide composition, the amino acid, carbohydrate, or mixture thereof content is from about 2 wt% to about 5 wt%, or from about 3 wt% to about 5 wt%. For example, a mixture of methylcellulose and zein can be used.

[0343] In some embodiments, the iron particles and / or iron oxide particles comprise iron, Fe3O4, and an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 95 wt%, the Fe3O4 content is less than 2 wt%, and the amino acid, carbohydrate, or mixture thereof content is from about 3 wt% to about 5 wt%.

[0344] In some embodiments, the iron particles and / or iron oxide particles are provided in the form of a powder having a particle size of from about 10 nm to about 100 μm. In other embodiments, the iron particles and / or iron oxide particles have a particle size of from about 10 nm to about 100 μm. In other embodiments, the iron particles and / or iron oxide particles have a particle size of from about 10 nm to about 800 μm. The iron particles and / or iron oxide particles can be micron-sized particles. In other embodiments, the particle size is from about 1 μm to about 700 μm, from about 1 μm to about 600 μm, from about 1 μm to about 500 μm, from about 1 μm to about 400 μm, from about 1 μm to about 300 μm, from about 1 μm to about 200 μm, from about 1 μm to about 100 μm, from about 1 μm to about 90 μm, from about 1 μm to about 80 μm, from about 1 μm to about 70 μm, from about 1 μm to about 60 μm, from about 1 μm to about 50 μm, from about 1 μm to about 40 μm, from about 1 μm to about 30 μm, or from about 10 μm to about 40 μm.

[0345] In some embodiments, the iron particles and / or iron oxide particles are a plurality of micron-sized particles. For example, the particles can have an iron core, which can be encapsulated by a shell. In some embodiments, the shell comprises an amino acid, a carbohydrate, or a mixture thereof. In some embodiments, the shell comprises an amino acid. In some embodiments, the shell comprises a carbohydrate.

[0346] In some embodiments, the iron particles and / or iron oxide particles are a plurality of iron core-shell micron-sized particles, wherein the core comprises Fe and the shell comprises an amino acid. In other embodiments, the iron particles and / or iron oxide particles are a plurality of iron core-shell micron-sized particles, wherein the core comprises Fe, the shell comprises an amino acid, and the interface between the core and the shell comprises an iron oxide. In some embodiments, the iron oxide is Fe3O4. In some embodiments, the amino acid is selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, or a combination thereof.

[0347] Advantageously, when the iron particles are encapsulated by a shell, the iron core can be protected by a shell material containing amino acids and / or carbohydrates. This can further delay the formation of iron oxides, thereby delaying the generation of ROS until it is used in the face mask. This prevents or reduces the over-oxidation of the iron particles, thereby enabling the face mask to have a longer shelf life and / or generate ROS more persistently for a longer time. In addition, the amino acid and / or carbohydrate encapsulation material can change the electric potential of the iron core and alter the redox reaction pathway. For example, the generated iron oxide can form an interfacial layer between the shell and the iron core. This enables the generation and release of ROS to be controlled. In this way, the shell on the iron particles controls the oxidation rate of iron, so that ROS can be continuously released, which is sufficient to achieve antibacterial and / or antiviral effects. This improves its applicability for various uses and allows for additional cleaning. A further advantage is that since natural compounds such as biopolymers are used to encapsulate the iron particles, the biodegradability of the biopolymer causes the shell to decompose over time. For example, the shell will decompose over time after multiple cleanings. This provides additional antibacterial and / or antiviral persistence effects because the inner iron core, which was previously more difficult to reach, can now be more easily reached.

[0348] In some embodiments, the thickness of the shell is from about 5 nm to about 1 μm, or from about 50 nm to about 400 nm. In other embodiments, the thickness is from about 50 nm to 350 nm, from about 50 nm to about 300 nm, from about 100 nm to about 300 nm, from about 150 nm to about 300 nm, or from about 200 nm to about 300 nm.

[0349] The shell can also contain iron. In this regard, in some embodiments, the shell contains iron and amino acids, carbohydrates, or a mixture thereof. Advantageously, since the iron is closer to the surface of the particle, the presence of iron in the shell can "prime" the oxidation of iron to iron oxide. In this sense, the initial burst of ROS provided by the face mask can provide protection for the user upon first use of the face mask and before sufficient water is provided to the iron core as moisture.

[0350] In some embodiments, the iron particles and / or iron oxide particles are a plurality of iron core-shell micron-sized particles, wherein the core contains Fe and the shell contains Fe and an amino acid. In other embodiments, the iron particles and / or iron oxide particles are a plurality of iron core-shell micron-sized particles, wherein the core contains Fe, the shell contains Fe and an amino acid, and the interface between the core and the shell contains an iron oxide. In some embodiments, the iron oxide is Fe3O4. In some embodiments, the amino acid is selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, taurine, betaine, N-methylalanine, or a combination thereof.

[0351] In some embodiments, the iron oxide particles are at least partially passivated by phenolic compounds in the cashew nut shell extract. In some embodiments, the iron oxide particles are at least partially passivated by amino acids in the cashew nut shell extract. In some embodiments, the iron oxide particles are at least partially passivated by sugars in the cashew nut shell extract. In some embodiments, the iron oxide particles are also at least partially passivated by a carboxylic acid moiety or a hydroxyl moiety.

[0352] In some embodiments, the carboxylic acid is selected from fatty acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, keto acids, α-hydroxy acids, divinyl ether fatty acids, phosphoric acid, polyphosphoric acid, tungstic acid, vanadic acid, molybdic acid, heteropolyacids, or a combination thereof.

[0353] In some embodiments, the iron oxide particles contain elemental Fe, FeO, Fe2O3, Fe3O4, or a combination thereof.

[0354] The present invention also provides an iron-iron oxide composition, which comprises:

[0355] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or a combination thereof;

[0356] b) proteins, amino acids, sugars, or a combination thereof; and

[0357] c) iron particles and / or iron oxide particles;

[0358] wherein the iron particles and / or iron oxide particles are at least partially passivated by the phenolic compounds.

[0359] By adding the cashew nut shell extract to the iron / iron oxide particles or onto the iron / iron oxide particles during a synthesis reaction, the antimicrobial efficacy of the composition can be further enhanced; that is, at least a chemical reaction occurs between the phenolic compounds and the iron / iron oxide particles.

[0360] The present invention also provides a method for synthesizing an iron-iron oxide composition, which comprises:

[0361] a) reacting a cashew nut shell extract with iron powder to form iron oxide particles;

[0362] wherein the cashew nut shell extract contains phenolic compounds;

[0363] wherein the cashew nut shell extract contains proteins, amino acids, sugars, or combinations thereof;

[0364] wherein the iron oxide particles are at least partially passivated by the cashew nut shell extract.

[0365] Advantageously, by reacting the cashew nut shell extract with iron powder, an activated shell of iron oxide and cashew nut shell extract can be formed on the core of elemental iron or an iron alloy. The thickness of the iron oxide shell can be controlled by the reaction conditions and the ratio of the amount of cashew nut shell extract to iron powder. The formation of the cashew-iron oxide shell provides greater antimicrobial efficacy because of the longer retention time and increased contact surface area. In addition, it has been found that having a core containing elemental iron or an iron alloy is advantageous because it regenerates the outer iron oxide shell when the shell "is depleted".

[0366] In some embodiments, the shell also contains components of the cashew nut shell extract. The components are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0367] In some embodiments, the iron oxide particles are at least partially passivated by phenolic compounds. To this end, the unreacted cashew nut shell extract can be physically adsorbed on the surface of the iron oxide particles by similar interactions. This provides greater stability to the composition and thus a longer shelf life.

[0368] In some embodiments, the method further comprises a step of reacting the product of step (a) with an iron oxide precursor to form iron oxide particles.

[0369] In some embodiments, the reaction step comprises nitrogen purging a mixture of the cashew nut shell extract and iron powder.

[0370] In some embodiments, the reaction step is carried out at about 50 °C to about 180 °C. In some embodiments, the reaction is carried out at about 5 °C to about 80 °C.

[0371] In some embodiments, the reaction step is carried out for about 1 h to about 50 h. In some embodiments, the reaction is carried out for about 1 minute to about 24 h.

[0372] In some embodiments, the reaction step is carried out in a solvent selected from an aqueous medium, an alcohol, or N,N-dimethylformamide.

[0373] In some embodiments, the reaction step further includes an acid selected from carboxylic acids, amino acids, or combinations thereof.

[0374] In some embodiments, the carboxylic acid is selected from fatty acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, keto acids, α-hydroxy acids, divinyl ether fatty acids, phosphoric acid, polyphosphoric acid, tungstic acid, vanadic acid, molybdic acid, heteropoly acids, or combinations thereof.

[0375] In some embodiments, the carboxylic acid is selected from benzoic acid, phosphoric acid, sulfuric acid, or combinations thereof.

[0376] In some embodiments, the weight ratio of iron powder to acid is from about 1:100 to about 100:1.

[0377] In some embodiments, the average particle size of the iron powder is from about 10 nm to about 800 μm.

[0378] In some embodiments, the iron oxide particles are core-shell particles, wherein the core is an iron core or an iron alloy core; the shell is an iron oxide shell.

[0379] Thus, in some embodiments, a method for synthesizing an iron-iron oxide composition includes:

[0380] reacting the cashew seed coat extract with iron particles and an iron oxide precursor to form iron-iron oxide core-shell particles having an elemental iron core or an iron alloy core and an iron oxide shell;

[0381] wherein the cashew seed coat extract contains components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0382] wherein the iron particles and / or the iron oxide particles are at least partially passivated by the cashew seed coat extract.

[0383] In some embodiments, the iron particles and the iron oxide precursor are uniformly mixed and then reacted with the cashew seed coat extract. This makes the shell coating on the iron particles more uniform.

[0384] In some embodiments, when the cashew seed coat extract contains phenolic compounds, the weight ratio of the phenolic compounds to the iron particles and the iron oxide precursor is from about 1:500 to about 500:1. In other embodiments, the weight ratio is from about 1:200 to about 200:1, or from about 1:100 to 100:1.

[0385] The present invention also provides an iron-iron oxide composition, which comprises:

[0386] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or combinations thereof;

[0387] b) proteins, amino acids, sugars, or combinations thereof; and

[0388] c) Iron oxide particles;

[0389] wherein the iron oxide particles are core - shell particles, the core is a metallic iron core or an iron alloy core; the shell is an iron oxide shell; and

[0390] wherein the iron oxide particles are at least partially passivated by a phenolic compound.

[0391] The present invention also provides an iron - iron oxide composition, comprising:

[0392] a) Iron particles and / or iron oxide particles; and

[0393] b) Cashew nut shell extract;

[0394] wherein the iron particles and / or iron oxide particles are at least partially passivated by the cashew nut shell extract.

[0395] In some embodiments, the iron - iron oxide composition further comprises:

[0396] a) Iron particles and / or iron oxide particles; and

[0397] b) Cashew nut shell extract;

[0398] wherein the components comprised in the cashew nut shell extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin, p - coumaric acid, gallic acid, or combinations thereof; and

[0399] wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof.

[0400] In some embodiments, the iron - iron oxide composition comprises:

[0401] a) Cashew nut shell extract; and

[0402] b) Iron - iron oxide core - shell particles, the core is a metallic iron core or an iron alloy core, and the shell is an iron oxide shell;

[0403] wherein the iron particles and / or iron oxide particles are at least partially passivated by the cashew nut shell extract.

[0404] In some embodiments, the iron - iron oxide composition comprises:

[0405] a) Cashew nut shell extract; and

[0406] b) Iron - iron oxide core - shell particles, the core is a metallic iron core or an iron alloy core, and the shell is an iron oxide shell;

[0407] Wherein the components contained in the cashew seed coat extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p-coumaric acid, gallic acid, or combinations thereof; and

[0408] Wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof.

[0409] In some embodiments, the iron particles and / or iron oxide particles are also at least partially passivated by carboxylic acid moieties or hydroxyl moieties.

[0410] In some embodiments, the carboxylic acids are selected from fatty acids, aromatic carboxylic acids, dibasic acids, tribasic acids, keto acids, α-hydroxy acids, divinyl ether fatty acids, phosphoric acid, polyphosphoric acid, tungstic acid, vanadic acid, molybdic acid, heteropoly acids, or combinations thereof.

[0411] In some embodiments, the iron particles and / or iron oxide particles contain elemental Fe, FeO, Fe2O3, Fe3O4, or combinations thereof.

[0412] In some embodiments, the average particle size of the iron particles and / or iron oxide particles is from about 1 μm to about 800 μm.

[0413] In some embodiments, the shell also contains components of the cashew seed coat extract.

[0414] In some embodiments, the thickness of the shell is from about 5 nm to about 1 μm.

[0415] In some embodiments, relative to the iron-iron oxide composition, the iron and / or iron oxide content is greater than 99 wt%, and the cashew seed coat extract content is less than 1 wt%.

[0416] In some embodiments, relative to the iron-iron oxide composition, the iron content is greater than 85 wt%; the iron oxide content is less than 14 wt%.

[0417] In some embodiments, the iron-iron oxide composition further contains excipients selected from stabilizers, dispersants, colorants, or combinations thereof.

[0418] In some embodiments, the iron-iron oxide composition comprises:

[0419] a) cashew seed coat extract; and

[0420] b) iron-iron oxide core-shell particles, the core being a single elemental iron core or an iron alloy core, and the shell being an iron oxide shell;

[0421] wherein the cashew seed coat extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p - coumaric acid, gallic acid, or combinations thereof; and

[0422] wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof; and

[0423] wherein the iron - iron oxide particles have an average particle size of from about 1 μm to about 800 μm.

[0424] In some embodiments, the iron - iron oxide composition comprises:

[0425] a) a cashew seed coat extract; and

[0426] b) iron - iron oxide core - shell particles, wherein the core is a metallic iron core or an iron alloy core and the shell is an iron oxide shell;

[0427] wherein the cashew seed coat extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p - coumaric acid, gallic acid, or combinations thereof; and

[0428] wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0429] wherein the shell further comprises components of the cashew seed coat extract; and

[0430] wherein the iron - iron oxide particles have an average particle size of from about 1 μm to about 800 μm.

[0431] In some embodiments, the iron - iron oxide composition comprises:

[0432] a) a cashew seed coat extract; and

[0433] b) iron - iron oxide core - shell particles, wherein the core is a metallic iron core or an iron alloy core and the shell is an iron oxide shell;

[0434] wherein the cashew seed coat extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p - coumaric acid, gallic acid, or combinations thereof; and

[0435] wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0436] wherein the shell further comprises components of the cashew seed coat extract;

[0437] wherein the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm; and

[0438] wherein, relative to the iron-iron oxide composition, the iron content is from about 20 wt% to about 80 wt% and the oxygen content is from about 15 wt% to about 40 wt%.

[0439] In some embodiments, the iron-iron oxide composition comprises:

[0440] a) a cashew seed coat extract; and

[0441] b) iron-iron oxide core-shell particles, wherein the core is an elemental iron core or an iron alloy core and the shell is an iron oxide shell;

[0442] wherein the components comprised in the cashew seed coat extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or combinations thereof; and

[0443] wherein the iron particles and / or the iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0444] wherein the shell further comprises the components of the cashew seed coat extract;

[0445] wherein the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm;

[0446] wherein, relative to the iron-iron oxide composition, the iron content is from about 20 wt% to about 80 wt% and the oxygen content is from about 15 wt% to about 40 wt%; and

[0447] wherein, relative to the iron-iron oxide composition, the carbon content is from about 4 wt to about 50 wt%.

[0448] In some embodiments, the iron-iron oxide composition comprises:

[0449] a) a cashew seed coat extract; and

[0450] b) iron-iron oxide core-shell particles, wherein the core is an elemental iron core or an iron alloy core and the shell is an iron oxide shell;

[0451] wherein the components comprised in the cashew seed coat extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or combinations thereof; and

[0452] wherein the iron particles and / or the iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0453] wherein the shell further comprises components of the cashew nut testa extract;

[0454] wherein the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm;

[0455] wherein, relative to the iron-iron oxide composition, the iron content is about 20 wt% to about 80 wt% and the oxygen content is about 15 wt% to about 40 wt%;

[0456] wherein, relative to the iron-iron oxide composition, the carbon content is from about 4 wt to about 50 wt%; and

[0457] wherein the iron oxide is iron(II) oxide and iron(III) oxide.

[0458] In some embodiments, the iron-iron oxide composition comprises:

[0459] a) a cashew nut testa extract; and

[0460] b) iron-iron oxide core-shell particles, wherein the core is a elemental iron core or an iron alloy core and the shell is an iron oxide shell;

[0461] wherein the components comprised in the cashew nut testa extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or combinations thereof; and

[0462] wherein the iron particles and / or the iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0463] wherein the shell further comprises components of the cashew nut testa extract;

[0464] wherein the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm;

[0465] wherein, relative to the iron-iron oxide composition, the iron content is about 20 wt% to about 80 wt% and the oxygen content is about 15 wt% to about 40 wt%;

[0466] wherein, relative to the iron-iron oxide composition, the carbon content is from about 4 wt to about 50 wt%; and

[0467] wherein the iron oxide is iron(II) oxide and iron(III) oxide.

[0468] In some embodiments, the iron-iron oxide composition comprises:

[0469] a) a cashew nut testa extract; and

[0470] b) Iron-iron oxide core-shell particles, where the core is an elemental iron core or an iron alloy core, and the shell is an iron oxide shell;

[0471] wherein the components comprised in the cashew seed coat extract are selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin gallate, p-coumaric acid, gallic acid, or combinations thereof; and

[0472] wherein the iron particles and / or iron oxide particles are at least partially passivated by proteins, amino acids, sugars, phenolic compounds, or combinations thereof;

[0473] wherein the shell further comprises components of the cashew seed coat extract;

[0474] wherein the average particle size of the iron-iron oxide particles is from about 1 μm to about 800 μm;

[0475] wherein, relative to the iron-iron oxide composition, the iron content is from about 20 wt% to about 80 wt% and the oxygen content is from about 15 wt% to about 40 wt%;

[0476] wherein, relative to the iron-iron oxide composition, the carbon content is from about 4 wt to about 50 wt%; and

[0477] wherein the iron oxide is iron(III) oxide.

[0478] The present invention also provides a method for synthesizing an iron-iron oxide composition, which comprises:

[0479] a) reacting a cashew seed coat extract with an iron oxide particle precursor to form iron oxide nanoparticles;

[0480] wherein the cashew seed coat extract comprises phenolic compounds;

[0481] wherein the cashew seed coat extract comprises proteins, amino acids, sugars, or combinations thereof;

[0482] wherein the iron oxide nanoparticles are at least partially passivated by phenolic compounds.

[0483] Without wishing to be bound by theory, the inventors believe that under suitable conditions, iron oxide nanoparticles can be synthesized by a plant-mediated green chemistry method using a plant extract as a reducing agent and a metal as a precursor. The process consists of three steps: (1) an activation stage, where metal ions are reduced by phenolic compounds in the plant extract and then nucleated by reduced metal atoms; (2) a growth stage, where small NPs stick together to form large-sized NPs (Ostwald ripening); and (3) a termination stage, where the NPs acquire their shape. The phenolic compounds can also act as stabilizers, covering the surface of the nanoparticles.

[0484] Advantageously, by reacting the cashew nut shell extract with an iron oxide precursor, activated iron oxide and cashew nut shell extract nanoparticles can be formed. In this method, the entire nanoparticle is activated. The iron oxide nanoparticles can be controlled by the reaction conditions and the ratio of the amount of cashew nut shell extract to the iron oxide precursor. It has been found that due to the increase in surface area and surface energy, these nanoparticles are more active, which is beneficial to the dissolution equilibrium.

[0485] In some embodiments, the iron oxide nanoparticles contain elemental iron. In other embodiments, the iron oxide nanoparticles contain an iron-cashew nut shell extract complex. In other embodiments, the iron oxide nanoparticles contain an iron-phenolic compound complex. To this end, the nanoparticles are composed of a network or matrix of iron atoms and phenolic compounds (or at least carbon atoms).

[0486] In some embodiments, the iron oxide nanoparticles are at least partially passivated by phenolic compounds. To this end, the unreacted cashew nut shell extract can be physically adsorbed on the surface of the iron oxide nanoparticles through similar interactions. This provides greater stability to the composition and thus a longer shelf life.

[0487] In some embodiments, the volume ratio or weight ratio of the cashew nut shell extract to the iron oxide precursor is from about 100:1 to about 1:100. In other embodiments, the ratio is about 90:1, 80:1, 70:1, 60:1, 50:1, 40:1, 30:1, 20:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80 or 1:90.

[0488] In some embodiments, the average particle size of the iron oxide nanoparticles is from about 1 nm to about 1000 nm. In other embodiments, the average particle size is from about 10 nm to about 50 nm.

[0489] In some embodiments, the method further comprises the step of reacting the iron oxide nanoparticles with iron powder to form iron oxide particles.

[0490] In the physical mixing and chemical reaction of the cashew nut shell extract composition with iron particles and / or iron oxide particles, the method may further comprise the step of adding a base. A base such as NaOH, KOH, NH4OH can be added to the iron particles and / or iron oxide particles. For example, the addition of the base can promote the formation of iron oxide on the iron particles through an oxidation process.

[0491] The base can also be added to the iron oxide particle precursor. Since Fe(OH)2 and Fe(OH)3 can be formed by the hydroxylation reaction of ferrous and ferric ions at pH > 8, the formation of iron oxide particles can be promoted.

[0492] The base can also be added to the cashew seed coat extract composition. For example, the oxidation of phenolic compounds can be controlled by the amount of NaOH added in the reaction. This can drive the formation of iron oxide particles and the adsorption of phenolic compounds for passivating the surface. In addition, by controlling the pH value to control the ionization of phenolic compounds in the cashew seed coat extract composition, the antimicrobial efficacy can be changed.

[0493] The present invention also provides an iron-iron oxide composition, comprising:

[0494] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin, p-coumaric acid, gallic acid, or a combination thereof;

[0495] b) proteins, amino acids, sugars, or a combination thereof; and

[0496] c) iron oxide nanoparticles;

[0497] wherein the iron oxide nanoparticles are at least partially passivated by the phenolic compounds.

[0498] The present invention also provides a method for synthesizing an iron-iron oxide composition, comprising:

[0499] a) reacting a cashew seed coat extract with iron powder and an iron oxide particle precursor in any order to form iron oxide particles; and

[0500] wherein the cashew seed coat extract contains phenolic compounds;

[0501] wherein the cashew seed coat extract contains proteins, amino acids, sugars, or a combination thereof;

[0502] wherein the iron oxide particles are at least partially passivated by the cashew seed coat extract.

[0503] For example, the addition order of the reagents for the reaction can be:

[0504]

[0505] The present invention also provides a method for synthesizing an iron-iron oxide composition, comprising:

[0506] a) reacting a cashew seed coat extract with iron powder to form iron particles;

[0507] b) reacting the iron particles with an iron oxide particle precursor to form iron oxide particles; and

[0508] wherein the cashew seed coat extract comprises phenolic compounds;

[0509] wherein the cashew seed coat extract comprises proteins, amino acids, sugars, or combinations thereof;

[0510] wherein the iron oxide particles are at least partially passivated by the cashew seed coat extract.

[0511] Advantageously, the method produces a uniform activated iron oxide cashew extract shell on the iron core. By further reacting with an iron oxide precursor, the thickness of the shell can be increased, thereby increasing the amount of active ingredient present at any given time. More advantageously, the stability of the particles is increased.

[0512] In some embodiments, the shell comprises an iron-cashew seed coat extract complex. In other embodiments, the shell comprises an iron-phenolic compound complex. To this end, the shell consists of a network or matrix of iron atoms and phenolic compounds (or at least carbon atoms).

[0513] In some embodiments, the iron oxide particle precursor is an iron(III) salt.

[0514] In some embodiments, the anion of the iron(III) salt is selected from nitrate, chloride, bromide, fluoride, iodide, sulfate, oxalate, perchlorate, phosphate, tetrafluoroborate, or combinations thereof. The iron(III) salt can be in its hydrated form.

[0515] In some embodiments, the volume ratio or weight ratio of the cashew seed coat extract to iron powder is from about 100:1 to about 1:100.

[0516] In some embodiments, the volume ratio or weight ratio of the cashew seed coat extract containing iron powder to the iron oxide precursor is from about 100:1 to about 1:100.

[0517] In some embodiments, the volume ratio or weight ratio of the phenolic compound to iron powder is from about 1:100 to about 100:1.

[0518] In some embodiments, the volume ratio or weight ratio of the phenolic compound to the iron oxide particle precursor is from about 1:100 to about 1:100.

[0519] In some embodiments, the reaction step further comprises an acid selected from carboxylic acids, amino acids, or combinations thereof.

[0520] In some embodiments, the carboxylic acid is selected from fatty acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, keto acids, α-hydroxy acids, divinyl ether fatty acids, phosphoric acid, polyphosphoric acid, tungstic acid, vanadic acid, molybdic acid, heteropolyacids, or combinations thereof.

[0521] In some embodiments, the carboxylic acid is selected from benzoic acid, phosphoric acid, sulfuric acid, or combinations thereof.

[0522] In some embodiments, the weight ratio of iron powder to acid is from about 1:100 to about 100:1.

[0523] In some embodiments, the average particle size of the iron powder is from about 10 nm to about 100 μm.

[0524] In some embodiments, the reaction step is carried out at about 50 °C to about 180 °C.

[0525] In some embodiments, the reaction step is carried out for about 1 h to about 50 h.

[0526] In some embodiments, the reaction step is carried out in a solvent selected from an aqueous medium, an alcohol, or N,N-dimethylformamide.

[0527] In some embodiments, the iron oxide particles are core-shell particles, wherein the core is a metallic iron core or an iron alloy core; and the shell is an iron oxide shell.

[0528] In some embodiments, the shell is a uniform shell. As used herein, "uniform" means that the shell has the same proportion of components throughout. In this regard, the shell is an iron oxide layer in which the cashew nut shell extract is uniformly dispersed (or at least at the interface). The entire thickness of the shell can also be uniform. For example, the thickness measured at various parts of a single iron oxide particle can vary within a range of less than 30%, less than 20%, or less than 10% (or have a standard deviation).

[0529] The present invention also provides an iron-iron oxide composition comprising:

[0530] a) a phenolic compound selected from tannins, catechins, epicatechins, epigallocatechins, p-coumaric acid, gallic acid, or combinations thereof;

[0531] b) a protein, an amino acid, a sugar, or combinations thereof; and

[0532] c) iron oxide particles;

[0533] wherein the iron oxide particles are core-shell particles, the core is an iron core or an iron alloy core; the shell is an iron oxide shell; and

[0534] wherein the iron oxide particles are at least partially passivated by the phenolic compound.

[0535] The present invention also provides a method for synthesizing an iron-iron oxide composition, comprising:

[0536] a) reacting a cashew nut shell extract with a precursor of iron oxide particles to form iron oxide nanoparticles;

[0537] b) reacting iron oxide nanoparticles with iron powder to form iron oxide particles; and

[0538] wherein the cashew seed coat extract comprises phenolic compounds;

[0539] wherein the cashew seed coat extract comprises proteins, amino acids, sugars, or combinations thereof;

[0540] wherein the iron oxide particles are at least partially passivated by phenolic compounds.

[0541] Advantageously, by first forming iron oxide nanoparticles and then attaching the nanoparticles to larger iron powder, particles with a patchy shell of iron oxide are formed on an iron core. Due to the patchiness of the shell, the activity of the iron oxide is increased while the aggregation problem of the nanoparticles is minimized. In addition, since the nanoparticles are adhered to heavier and larger particles, the retention on the surface is improved; i.e., the nanoparticles are less likely to be washed off.

[0542] As used herein, "patchy particles" or "patchy nanoparticles" are micron-scale or nanoscale colloidal particles of an anisotropic type. They can be obtained by modifying the particle surface chemistry ("enthalpy patch"), particle shape ("entropy patch"), or both.

[0543] In some embodiments, the iron oxide particles are core-shell particles, where the core is an iron core or an iron alloy core; and the shell is a patchy shell of iron oxide nanoparticles.

[0544] In some embodiments, the volume ratio or weight ratio of the cashew seed coat extract to the iron oxide precursor is from about 100:1 to about 1:100.

[0545] In some embodiments, the volume ratio or weight ratio of the iron oxide nanoparticle precursor to the iron powder is from about 100:1 to about 1:100.

[0546] The present invention also provides an iron-iron oxide composition comprising:

[0547] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin gallate, p-coumaric acid, gallic acid, or combinations thereof;

[0548] b) proteins, amino acids, sugars, or combinations thereof; and

[0549] c) iron oxide particles;

[0550] wherein the iron oxide particles are core-shell particles, where the core is an iron core or an iron alloy core; and the shell is a patchy shell of iron oxide nanoparticles; and

[0551] wherein the iron oxide particles are at least partially passivated by phenolic compounds.

[0552] In some embodiments, relative to the iron-iron oxide composition, the iron content of the iron-iron oxide composition is from about 20 wt% to about 80 wt%, from about 20 wt% to about 70 wt%, from about 20 wt% to about 60 wt%, from about 20 wt% to about 50 wt%, from about 20 wt% to about 40 wt%, from about 20 wt% to about 30 wt%, from about 20 wt% to about 30 wt%, from about 20 wt% to about 29 wt%, from about 20 wt% to about 28 wt%, from about 20 wt% to about 27 wt%, from about 20 wt% to about 26 wt%, or from about 20 wt% to about 25 wt%.

[0553] In some embodiments, relative to the iron-iron oxide composition, the oxygen content of the iron-iron oxide composition is from about 15 wt% to about 40 wt%, from about 20 wt% to about 40 wt%, from about 20 wt% to about 38 wt%, from about 20 wt% to about 36 wt%, from about 20 wt% to about 34 wt%, from about 20 wt% to about 32 wt%, from about 20 wt% to about 30 wt%, or from about 20 wt% to about 28 wt%.

[0554] In some embodiments, relative to the iron-iron oxide composition, the carbon content of the iron-iron oxide composition is from about 4 wt% to about 50 wt%, from about 10 wt% to about 50 wt%, from about 20 wt% to about 50 wt%, from about 30 wt% to about 50 wt%, from about 32 wt% to about 50 wt%, from about 34 wt% to about 50 wt%, from about 36 wt% to about 50 wt%, from about 38 wt% to about 50 wt%, from about 40 wt% to about 50 wt%, from about 42 wt% to about 50 wt%, or from about 44 wt% to about 50 wt%.

[0555] The cashew seed coat extract composition may also comprise excipients such as surfactants, stabilizers, and / or polymers. Such excipients can improve the dispersion of iron particles and / or iron oxide particles in the application medium. A surfactant is a compound that reduces the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Examples of surfactants include sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), octylphenoxypolyethoxyethanol, polyoxyethylene mono-p-tert-octylphenyl ether, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), DOC, ethoxylated nonylphenol (NP-40), octyl-β-D-thioglucopyranoside, octyl glucoside, and dodecyl maltoside. A stabilizer is a chemical substance used to prevent degradation caused by, for example, heat and / or light. For example, antioxidants such as oxygen scavengers, persistent radical scavengers, and anti-ozonants can be added to further control the production rate of ROS (as disclosed herein). Chelating agents can also be added to form chelate complexes and deactivate trace metal ions on the surface, which would otherwise act as catalysts or inactivate the composition. UV stabilizers (UV absorbers and quenchers) can also be added to protect the composition from degradation. Polymers including polyelectrolytes such as polyacrylic acid (PAA), poly(sodium styrenesulfonate) (PSS), polyethyleneimine (PEI), poly(lactic-co-glycolic acid) (PLGA), and fluoropolymers can be added to improve the application on the surface and increase the retention time of ROS.

[0556] The present invention also provides a method for synthesizing an iron-iron oxide composition, which comprises:

[0557] a) Mixing a cashew seed coat extract with a citrus extract to obtain a cashew seed coat extract composition;

[0558] wherein the cashew seed coat extract comprises phenolic compounds;

[0559] wherein the cashew seed coat extract comprises proteins, amino acids, sugars, or combinations thereof.

[0560] In some embodiments, the citrus extract is synthesized by the following steps:

[0561] a) Dispersing citrus peel powder in an extractant to form a mixture;

[0562] b) Incubating the mixture; and

[0563] c) Filtering the mixture to obtain the citrus extract;

[0564] wherein the citrus extract comprises terpene compounds.

[0565] The citrus extract may also be referred to as orange extract, or orange peel extract.

[0566] In some embodiments, the extractant is selected from an aqueous medium, an alcohol, hydroxyethyl cellulose, propylene glycol, or a combination thereof.

[0567] In some embodiments, the incubation step (b) is carried out for about 1 h to about 50 h.

[0568] In some embodiments, the incubation step (b) is carried out with stirring.

[0569] In some embodiments, the terpene compounds are selected from α-pinene, sabinene, myrcene, limonene, linalool, citronellal, neral, geraniol, or a combination thereof.

[0570] In some embodiments, the citrus extract further comprises phenolic compounds.

[0571] The present invention also provides an iron-iron oxide composition, comprising:

[0572] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin gallate, p-coumaric acid, gallic acid, or a combination thereof;

[0573] b) proteins, amino acids, sugars, or a combination thereof; and

[0574] c) a citrus extract;

[0575] wherein the citrus extract comprises terpene compounds.

[0576] The present invention also provides an iron-iron oxide composition, comprising:

[0577] a) phenolic compounds selected from tannins, catechins, epicatechins, epigallocatechin gallate, p-coumaric acid, gallic acid, or a combination thereof;

[0578] b) proteins, amino acids, sugars, or a combination thereof;

[0579] c) iron oxide particles; and

[0580] d) a citrus extract;

[0581] wherein the iron oxide particles are at least partially passivated by the phenolic compounds; and

[0582] wherein the citrus extract comprises terpene compounds.

[0583] The present invention is based in part on the discovery that iron oxide particles formed from cashew seed coat extract can generate different ROS, including superoxide, singlet oxygen, and hydroxyl radicals. Due to the interaction of the iron oxide particles with the phenolic compounds of the cashew seed coat extract, ROS can be generated in the dark, i.e., without ultraviolet radiation. More advantageously, since ROS are continuously released through autocorrosion, no external stimulation is required. When applied to a surface, this is beneficial for providing a continuous "active" surface.

[0584] In particular, when the iron oxide particles form iron core-iron oxide shell particles, the core-shell structure creates a special interface between the iron core and the iron complex shell, changing the potential of the iron core and the redox reaction pathway. For this reason, it is believed that this autocorrosion process can also occur on Fe / Fe e O3, Fe / Fe e O3 particles, and / or combinations thereof. The electrons generated by iron corrosion can be transferred to the conduction band (CB) of the iron oxide in an energy-favorable manner. The electrons in the CB are capable of reducing oxygen and generating ROS. In other words, electrons are contributed from iron to the iron oxide (CB) and reduce oxygen molecules to generate free radicals in an energy-favorable manner. The entire system does not rely on external stimulation, the ROS generation process can be manipulated, and has long-term stability. Then the ROS will kill the contacting bacteria and viruses. The ROS killing mechanism of this material is similar to photocatalytic materials such as ZnO and TiO2, but since the iron / iron oxide particles are autocatalytic materials, it does not rely on light irradiation to generate ROS. The iron particles sacrifice their iron cores to generate ROS.

[0585] The microbial killing mechanism of ROS is believed to be related to ˙O2 - 、H2O2、˙OH、 1 O2 and / or α-O.

[0586] The present invention provides methods for using iron-iron oxide compositions in antimicrobial applications. The iron-iron oxide compositions disclosed herein can be in any suitable form. For example, the composition can be in the form of a gel, a liquid, or a sprayable form.

[0587] The present invention also provides a method for cleaning a non-biological surface, which includes:

[0588] a) contacting the iron-iron oxide composition with the non-biological surface.

[0589] As used herein, "cleaning" refers to the act of making something clean by, for example, removing dirt, marks, or stains. As shown herein, the iron-iron oxide composition is also capable of degrading colored compounds. Through this degradation, the color of the compound is lost due to the disruption of its aromaticity / conjugated system.

[0590] The present invention also provides a method for disinfecting a non-biological surface, which comprises:

[0591] a) contacting an iron-iron oxide composition with the non-biological surface.

[0592] As used herein, "disinfection" refers to the act of cleaning something to eliminate microorganisms such as bacteria and / or viruses.

[0593] In some embodiments, ROS can be generated in the dark. In other embodiments, ROS can be generated without ultraviolet radiation. In other embodiments, the generation of ROS is selected from ˙O2 - , H2O2, ˙OH, 1 O2, α-O, or a combination thereof.

[0594] In some embodiments, when FeCl3 is used in the synthesis, the presence of Cl - anions also contributes to the generation of ROS. ROS can be Cl˙ and / or Cl2 - ˙. This is more advantageous because the antimicrobial effect can be enhanced, especially it can also extend a certain distance from the application surface. In this sense, the antimicrobial effect can be obtained without the microorganisms contacting the surface.

[0595] In some embodiments, ROS can be dispersed at a certain distance from the application area or surface. In other embodiments, the distance is from about 0.1 mm to about 10 cm. In other embodiments, the distance is about 1 cm, 2 cm, 5 cm, 7 cm or 10 cm.

[0596] In some embodiments, the iron / iron oxide composition can reduce the microbial activity by at least 2 log after 5 minutes.

[0597] The method further comprises the step of applying the iron-iron oxide composition to an application medium before (a).

[0598] In some embodiments, the application medium is a textile, plastic or cellulose product. In some embodiments, the application medium is a non-woven fabric such as polyester or melt-blown polypropylene. Such products can be used as cleaning and / or disinfection wipes, or form part of personal protective equipment.

[0599] Thus, the iron-iron oxide composition can be used in detergents, aerosols, disinfectants, general cleaners, pest control solutions and dishwashing liquids.

[0600] For example, in order to be suitable for use as a spray, a viscosity reducing agent can be added to obtain a viscosity of from about 80,000 cPs to about 900,000 cPs. Since the iron particles are nanoscale and / or micron scale, they can be dispersed and suspended in the air within an appropriate time. When sprayed on a surface, the unaggregated iron particles can also be evenly dispersed on the surface.

[0601] The iron-iron oxide composition can be used for air purification because when these substances come into contact with, for example, a treated surface, they can decompose harmful particulate matter, volatile organic compounds, and polycyclic aromatic hydrocarbons. The composition can also be used as an additional safety layer for coating air filters and filtration systems.

[0602] The iron-iron oxide composition can also be used in combination with a resin or polymer such as varnish to form an antimicrobial coating. The iron-iron oxide composition can also be used in combination with a resin or polymer such as varnish to form an antimicrobial coating.

[0603] The iron-iron oxide composition can also be used in wastewater treatment or management. For example, the composition can be added to wastewater to kill microorganisms and / or reduce aromatic colorants and impurities.

[0604] It can also be used for water purification. In some embodiments, the iron / iron oxide composition can reduce the dyeing effect by at least 60%. In some embodiments, the iron / iron oxide composition can reduce the dyeing effect of Brilliant Blue R by at least 60%.

[0605] The present invention also provides a method for using an iron-iron oxide composition in skin care applications, which includes:

[0606] contacting the iron-iron oxide composition with the skin of a subject in need thereof.

[0607] The present invention also provides the use of an iron-iron oxide composition for cleaning an abiotic surface, which includes:

[0608] a) contacting the iron-iron oxide composition with the abiotic surface.

[0609] The present invention also provides the use of an iron-iron oxide composition for disinfecting an abiotic surface, which includes:

[0610] a) contacting the iron-iron oxide composition with the abiotic surface.

[0611] The present invention also provides the use of an iron-iron oxide composition in skin care applications, which includes:

[0612] contacting the iron-iron oxide composition with the skin of a subject in need thereof.

[0613] The present invention also provides a disinfectant comprising the iron-iron oxide composition disclosed herein.

[0614] The present invention also provides a cleaning agent comprising the iron-iron oxide composition disclosed herein.

[0615] The present invention also provides a detergent, an aerosol, a pest control solution, and a dishwashing liquid comprising the iron-iron oxide composition disclosed herein.

[0616] The present invention also provides a coating composition comprising the iron-iron oxide composition disclosed herein for coating a surface.

[0617] Examples

[0618] Manufacturing process of composite materials

[0619] The iron-iron oxide composition is applied to the fabric by a padding machine located at the entrance of a stentering machine. The fabric is then cured in a 10-chamber stentering machine at 120 °C for 7 minutes. Then, the adhesion between the metal oxide and the fabric is enhanced by applying a waterproof coating and the fabric is passed through the stentering machine again. Using this process, a coating is formed on the fabric surface, ensuring the persistence of antibacterial and / or antiviral properties and lasting up to 30 washes. This process also helps to optimize the particle filtration efficiency of the face mask. This process plays a dual role in this process.

[0620] Manufacturing process of face masks

[0621] To improve the efficacy of the face mask, a heat transfer fusing machine can be optionally used to fuse the non-woven filter layer with the composite fabric layer. Then, an automatic cutting machine is used to die-cut several layers of the face mask according to the paper template of the face mask. Then, it is stitched together according to the manufacturing instructions to form the shape of the face mask.

[0622] Antibacterial test of face masks and their composite materials

[0623] Antimicrobial finish evaluation of textile materials (AATCC 100-2012) was used. Briefly, the material was washed in a gentle cycle machine at 80 °F and then tumble dried at low temperature. Then, the material was tested under the following conditions:

[0624] · Staphylococcus aureus ATCC 29213

[0625] · Dilution medium: PBS

[0626] · Sample size # layers: 1

[0627] · Sterilization: None

[0628] · Neutralizer: 0.9% NaCl + 0.2% Tween

[0629] · Target inoculation level: (1.0 - 2.0)×10 6 CFU / ml

[0630] · Inoculum volume: 1.0 ml

[0631] · Contact time: 24 h

[0632] · Temperature: 37 + / - 2 °C

[0633] It was found that after 24 hours, a 98% to 100% reduction in bacteria was observed.

[0634] Bacterial filtration efficiency 1 (ASTM test method F2101)

[0635] A suspension of Staphylococcus aureus (ATCC 29213) was delivered to the test article to determine the filtration efficiency. A challenge level of greater than 10 7 colony forming units (CFU) was obtained by aerosol spraying. This method was adapted from ASTM F2101. The test was not conducted at a fixed flow rate of 28.3 l / min, but at a more stringent level. The uncollected aerosol particles were collected by a six-stage Andersen sampler. However, sufficient controls were included to verify the reliability of the study. All test method acceptance criteria were met. The conditions were as follows:

[0636] Challenge flow: Aerosol spraying

[0637] Condition parameters: 85 ± 5% relative humidity (RH) and 21 ± 5 °C for at least 4 hours

[0638] Test area: 15 cm × 15 cm

[0639] Test surface: Black surface

[0640] Challenge level: 1.8×10 7 CFU

[0641] Mean particle size (MPS): ~0.8 μm

[0642] After 20 washes, the average bacterial filtration efficiency of 5 test samples was 97.2%. After 30 washes, the average bacterial filtration efficiency of 5 test samples was 95.6%.

[0643] Since the face mask can filter up to 99.9998% of Staphylococcus aureus ATCC29213 bacteria with a size of ~0.8 μm, the face mask meets the fine particulate matter of 2.5 (PM2.5).

[0644] Bacterial filtration efficiency 2( BS EN 14683:2019)

[0645] Contact area for bacterial challenge: Inside the face mask

[0646] Flow rate: 28.3 ± 0.3 L / min

[0647] Average particle size of the challenge aerosol: 3 μm ± 0.3 μm

[0648] Test area: Approximately 50 cm 2

[0649] For the 5 face masks tested Bacterial filtration efficiency All exceeded 99.85%.

[0650] Antiviral efficacy

[0651] Cell line: Madin - Darby canine kidney (MDCK) cells

[0652] Virus: Influenza A virus (PR8#2 - 3)

[0653] Drugs / Chemicals: Slides coated with antimicrobial agents (labeled as control sample, sample 28, and sample 60)

[0654] Medium: DMEM - E10, overlay medium

[0655] Incubate and treat the virus with slides coated with antimicrobial agents for 1 h - Dilute the influenza A virus to 10 5 PFU / 100 μL and add it to the slides coated with control, sample 1, and sample 2. Thereafter, cover each slide with a thin paraffin film to ensure contact between the virus and the coated slide. After incubation for 1 hour, collect the supernatant for plaque assay.

[0656] Plaque assay - Seed MDCK cells in 12 - well plates respectively. Serial - dilute the supernatant from the influenza - treated samples to 10 -4 , and take 250 μL of the diluted supernatant and add it to the MDCK cells. Incubate the plate for 1 hour with a shaking interval of 15 minutes. Then wash the plate twice with 1×PBS and add 0.3% agarose overlay medium to each well. Incubate the plate for 2 days. Finally, remove the overlay medium and add crystal violet to stain the countable plaques. Then count the plaques using plaque - forming units per mL.

[0657] The results showed that, compared with the control group, the samples were sufficient to inhibit the virus by > 4.5 - log units (or at least 0.5 - log unit inhibition). The average plaque - assay virus titers of the control group and the samples were 4.53×10 4 PFU / mL and 0 PFU / ml (or at least 9.06×10 3 PFU / mL), respectively.

[0658] According to ISO18184:2019, after the mask / composite material was in contact with P22 phage for 24 hours, the overall reduction of phage was 99.98%.

[0659] According to ISO18184:2014, after the mask / composite material was in contact with enterovirus 71 for 2 hours, the overall reduction of the virus (antiviral activity rate) was 99.92%.

[0660] According to ISO18184:2014, after the mask / composite material was in contact with influenza A virus H1N1 for 2 hours, the overall reduction of the virus (antiviral activity rate) was 99.93%.

[0661] According to ISO18184:2014, after the mask / composite material was in contact with influenza A virus H3N2 for 5 minutes, the overall reduction of the virus (antiviral activity rate) was 97.25%. After the mask / composite material was in contact for 2 hours, the overall reduction (antiviral activity rate) was 99.52%. In contrast, when using only the iron oxide mask alone after 2 hours of contact, the overall reduction (antiviral activity rate) was 99.12%, while when using only the mask of cashew seed coat extract alone after 2 hours of contact, the overall reduction (antiviral activity rate) was 92.43%.

[0662] According to ISO18184:2019, after the mask / composite material was in contact with SARS-CoV-2 virus for 2 hours, the overall reduction (antiviral activity rate) was 99.08%.

[0663] The mask / composite material was washed 15 times by hand after being exposed to the human coronavirus strain OC43 for 60 minutes, and its antiviral efficacy was tested.

[0664]

[0665] Under this evaluation condition, the mask / composite material can be classified as having good antiviral effect after being exposed for 60 minutes.

[0666] Waterproof - spray test

[0667] (BS EN 24920 / ISO4920 / DIN EN 24920 / AATCC 22)

[0668] Water temperature: 27 degrees Celsius

[0669] Water flow rate: 26 seconds

[0670] Temperature: 21 °C

[0671] Humidity: 66%

[0672] The average repellency of 3 samples exceeded 70.

[0673] Cytotoxicity test (ISO10993-5; ISO10993-12)

[0674] The composite material and the face mask are rated 0, indicating that they have no cytotoxic effect.

[0675] Cashew seed coat extract

[0676] · Appearance: Brown liquid

[0677] · Physicochemical properties: High free radical scavenging activity (antioxidant activity)

[0678] · Composition: A mixture of compounds containing catechin, epicatechin, and tannic acid

[0679] · Thermal stability up to 200 °C

[0680] · Solubility in water is 2850 g / L

[0681] Extraction of cashew seed coat - comparative example

[0682] Use a ball mill to grind the skin at 500 rpm for 1 hour until it becomes a fine powder. Then, collect the powder and add ultrapure water in a ratio of 1:10. Stir and incubate the entire mixture in a water bath at 37 °C for 1 hour. Then, centrifuge it at 10000 g for 10 minutes at 4 °C. Take the supernatant, carefully filter it through a 0.2-μm filter, and freeze-dry it.

[0683] Extraction of cashew seed coat - method 1

[0684] To obtain the cashew seed coat extract, the method disclosed in International Journal of Engineering Technology Science and Research, Volume 4(8), pages 671 to 675 (ISSN: 23943386) can be used. For example, the seed coat can be boiled in water at 40 °C to 100 °C for 1 to 24 hours. This extracts water-soluble polyphenols such as tannins from the seed coat. After heating, carefully filter the solution to remove any residual solid matter.

[0685] Example 1: Synthesis of iron - polyphenol composite particles (Fe - cashew core coated with Fe(NO3)3·9H2O shell) - Composite material A of

[0686] Prepare fresh cashew nut extract as described above and cool it to room temperature. Mix 1 mL to 50 mL of cashew nut extract with 2 g to 10 g of iron powder, and purge the mixture with nitrogen for 1 h. During this process, iron and cashew nut extract will connect to form a composite iron-cashew nut. Prepare 1 mL to 90 mL of 0.1 M Fe(NO3)3·9H2O solution separately and purge it with nitrogen for 1 h. Subsequently, mix the iron-cashew nut solution with 0.5 M Fe(NO3)3·9H2O. The reaction continues for 24 h under nitrogen, and the product is stored at 4 °C. Nanoparticles with an Fe-cashew nut core coated with a Fe(NO3)3·9H2O shell are obtained.( Figure 14 )

[0687] Alternatively, combine 2 g to 10 g of Fe and 1 mL to 50 mL of cashew nut extract, and stir constantly at room temperature for 1 h. Then add 1 mL to 90 mL of 0.1 M FeCl3, and incubate the mixture with constant stirring at room temperature for 1 h. Centrifuge the entire mixture at 5000 rpm and collect the precipitate. Wash the precipitate first with water and then with ethanol.

[0688] In the examples disclosed herein, different types of Fe salts were tested; for example, FeCl3, FeSO4, Fe2(SO4)3, Fe(NO3)3, Fe(NO3)2.

[0689] Example 2: Synthesis of iron - polyphenol composite particles (Fe core coated with cashew - Fe(NO3)3·9H2O shell) - Composite material B of

[0690] Purge 2 g to 10 g of iron powder with nitrogen in water for 1 h. Mix 1 mL to 50 mL of cashew nut solution and 1 mL to 90 mL of 0.1 M Fe(NO3)3·9H2O separately, and purge with nitrogen for 1 h to form a cashew nut-Fe(NO3)3·9H2O connected compound. Subsequently, mix the iron solution with the cashew nut-Fe(NO3)3·9H2O solution. The reaction continues for 24 h under nitrogen, and the product is stored at 4 °C. Nanoparticles with an Fe core coated with a cashew nut-Fe(NO3)3·9H2O shell are obtained.( Figure 15 )

[0691] Example 3: Synthesis of iron powder activated by cashew extract (Composite material C)

[0692] Mix fresh iron powder (1 g to 10 g) with cashew nut testa extract (1 mL to 50 mL), and stir at 80 °C for 24 hours. After cooling to room temperature, collect the solid residue of composite material C.

[0693] Example 4: Synthesis of iron nanoparticles of cashew extract (Composite material D)

[0694] 16.23 g of FeCl3 was added to 1 L of ultrapure water to prepare a 0.1 M FeCl3 solution. Subsequently, 1 mL to 90 mL of the 0.1 M FeCl3 solution was added to 1 mL to 50 mL of cashew nut extract. The formation of iron-cashew nanoparticles was marked by the appearance of a precipitate, which was collected by centrifugation at 7000 rpm. Then the iron-cashew nanoparticle powder was frozen at -20 °C and then dried at a pressure of 10 Pa in a freeze dryer at -45 °C for 24 h.

[0695] Alternatively, 1 mL to 90 mL of the 0.1 M FeCl3 solution could be incubated with 1 mL to 50 mL of cashew nut extract at room temperature for 1 hour. Then the entire mixture was centrifuged at 5000 rpm and the precipitate was collected. The precipitate was washed first with water and then with ethanol.

[0696] Example 5: Synthesis of iron nanoparticles of cashew extract (Composite material E)

[0697] 1 mL to 90 mL of 0.1 M FeCl3 + 1 mL to 50 mL of cashew seed coat extract were incubated at room temperature for 1 hour. Then 1 M NaOH was added until the pH reached 11. The entire mixture was centrifuged at 5000 rpm and the precipitate was collected. The precipitate was washed first with water and then with ethanol.

[0698] Example 6: Fe - FeCl3 as the core and cashew as the shell (Composite material F)

[0699] 1 g to 10 g of Fe + 1 mL to 90 mL of 0.1 M FeCl3 were combined and incubated at room temperature with constant stirring for 1 hour. Then 1 mL to 50 mL of cashew nut extract was added and the mixture was incubated at room temperature with constant stirring for 1 hour. The entire mixture was centrifuged at 5000 rpm and the precipitate was collected. The precipitate was washed first with water and then with ethanol.

[0700] Energy - dispersive X - ray spectroscopy (EDX) analysis of iron particles and / or iron oxide particles

[0701] The EDX results shown below are based on Examples 1, 2, and 6, using different amounts of iron particles, iron oxide precursors, and cashew seed coat extract.

[0702] Element wt% wt% σ C 50.60 0.62 O 27.13 0.56 Cl 0.89 0.08 Fe 21.37 0.42 Total; 100.00

[0703] Element wt% wt% σ C 36.22 0.36 O 39.39 0.32 Cl 1.14 0.04 Fe 23.25 0.23 Total; 100.00

[0704] Element wt% wt% σ C 31.15 0.40 O 40.18 0.34 Cl 1.43 0.05 Fe 27.24 0.27 Total: 100.00

[0705] Element wt% wt% σ C 31.25 0.38 O 40.38 0.33 Cl 0.77 0.04 Fe 27.61 0.26 Total; 100.00

[0706]

[0707] Scanning electron microscope (SEM) analysis

[0708] The SEM results of Examples 1, 2, and 6 are as Figure 20A - Figure 20E shown.

[0709] Antimicrobial effect of iron - cashew particles against Staphylococcus aureus

[0710]

[0711] Quantitative suspension test for evaluating bacterial activity

[0712]

[0713] Meet the requirements for bactericidal efficacy according to EN 1276.

[0714] Antiviral efficacy

[0715]

[0716] According to ISO 18184:2019, the mask / composite material showed an antiviral activity rate of 99.36% after 2 h of contact with the SARS-CoV-2 virus.

[0717] Degradation of Coomassie Brilliant Blue R dye

[0718] 0.1 g of iron-cashew seed coat nanoparticles was added to brilliant blue dye and incubated at room temperature for 15 min. The absorbance was measured at 550 nm using an ultraviolet spectrophotometer. The blank was used as a control. The results are as Figure 16 and Figure 17 shown.

[0719] Absorbance at 550 nm after 15 min (arbitrary unit):

[0720] Blank = 3.243

[0721] Comparative example (iron / iron oxide alone) = 2.905

[0722] Example 1 using Fe(NO3)3 = 0.882

[0723] Example 4 using FeCl3 = 2.59

[0724] Example 6 using FeSO4 = 2.926

[0725] Example 6 using FeCl3 = 2.87

[0726] Example 1 using FeSO4 = 2.81

[0727] The results showed that the cashew seed coat extract composition (when containing iron / iron oxide particles) was able to degrade dyes compared to the blank and comparative examples.

[0728] Application of antimicrobial composition on textiles

[0729] Pad-dry-cure is the most widely used process for 100% washed cotton fabrics. The cashew seed coat extract was treated with 1% to 80% (owf) of the fabric at room temperature. The treated fabric was passed between rollers two to three times under a uniform pressure of 1.5 bar to better penetrate the finishing agent and squeeze out the excess liquid from the fabric. Then the fabric was dried at 110 °C and cured in an oven at 130 °C for 3 minutes. The cashew seed coat extract had 99% antimicrobial activity against the common Gram-positive bacterium Staphylococcus aureus.

[0730] Application of antimicrobial composition (containing citrus extract) on textiles

[0731] Pad-dry-cure is the most widely used process for 100% washed cotton fabrics. Orange (Citrus) peel extract was treated with 1% to 80% (owf) of the fabric at room temperature. The treated fabric was passed between rollers two to three times under a uniform pressure of 1.5 bar to better penetrate the finishing agent and squeeze out the excess liquid from the fabric. Then the fabric was dried at 110 °C and cured in an oven at 130 °C for 3 minutes.

[0732] Antimicrobial test

[0733] The tests were conducted with samples of treated and untreated test materials. The materials were cut into 4.8 cm in diameter. According to the AATCC100 test procedure, about 1 - 2×10 5 CFU / ml of 1 ml of the test biological suspension was inoculated into the test samples. Samples of the cashew seed coat extract composition with iron particles and / or iron oxide particles were tested. The inoculated samples were incubated for a specific contact time. At the appropriate contact time, neutralizing broth was added to each container and the container was shaken for 1 minute to release the inoculum from the test sample into the neutralizing broth. Serial dilutions were made and plates were incubated. After incubation, the recovered colonies were counted and used to determine the percentage reduction.

[0734] The following results are related to the fabric samples. The percentage reduction was determined by comparing the samples after the contact time with the samples immediately after inoculation. The percentage reduction was converted to a log reduction as follows:

[0735] A 90% reduction = a 1 log decrease;

[0736] i.e., a reduction from 1000000 to 100000 is a 1 log decrease

[0737] A 99% reduction = a 2-log decrease;

[0738] That is, reducing 1,000,000 to 10,000 is a 2-log decrease.

[0739] A 99.9% reduction = a 3-log decrease;

[0740] That is, reducing 1,000,000 to 1,000 is a 3-log decrease.

[0741] A 99.99% reduction = a 4-log decrease;

[0742] That is, reducing 1,000,000 to 100 is a 4-log decrease.

[0743] Test information:

[0744] · Staphylococcus aureus ATCC 29213

[0745] · Dilution medium: PBS

[0746] · Sample size # layers: 1

[0747] · Sterilization: None

[0748] · Neutralizer: 0.9% NaCl + 0.2% Tween

[0749] · Target inoculation level: (1.0 - 2.0) × 10 5 CFU / ml

[0750] · Inoculum volume: 1.0 ml + / - 0.1 ml

[0751] · Contact time: 24 h

[0752] Temperature: 37 + / - 2 °C

[0753] AATCC100 test method for 24 - hour contact time Staphylococcus aureus Cashew A 3 - log reduction After 30 washes of cashew A 2 - log reduction Iron / iron oxide A 3 - log reduction

[0754] ATP test for long - term durability of coating (single application)

[0755]

[0756] Effect of citrus and (iron oxide + cashew) impregnated face masks at shorter contact times

[0757]

[0758] Test results against H3N2 virus

[0759]

[0760] Test results against HCoV - 229E virus

[0761]

[0762] Analysis of ·OH level generated by iron - cashew particles in water using hydroxyphenyl fluorescein (HPF) probe method

[0763] Example 1 using Fe(NO3)3 and Example 4 using FeCl3 were used as samples.

[0764] 0.01 g of the sample was added to a 1.5 mL centrifuge tube. 1 mL of 10 μM HPF detection solution was added to each sample. The solution was thoroughly mixed by vortexing and stored in the dark at room temperature. At a certain time point, the solution was centrifuged (16800 rpm × 5 min), and 100 μL of the solution was transferred to a black 96-well microplate for fluorescence detection. Fluorescence at 490 / 515 nm was collected using a microplate reader.

[0765] The type of ROS released by FeNO3-cashew (Example 1) after 2 hours in the dark was ·OH radicals. FeCl3-cashew (Method 1) did not release ·OH radicals ( Figure 18 ).

[0766] Determination of ·O2 free radical level in iron - cashew particles using nitroblue tetrazolium (NBT) method

[0767] Example 1 using Fe(NO3)3 and Example 4 using FeCl3 were used as samples.

[0768] 0.2 g of iron-cashew particles was added to 10 mL of an aqueous solution of 1000 mgL -1 NBT and placed in the dark. At a certain time point, the absorption spectrum of NBT was measured using a UV-Vis-NIR spectrophotometer. At 2 h, the absorption peak of NBT continued to decrease, indicating that FeCl3-cashew continuously generated ·O2 radicals and reacted with NBT ( Figure 19 ).

[0769] The comparative examples were prepared in a similar manner. The absorbance value of NBT did not change within a 2 h time interval.

[0770] It should be understood that many further modifications and permutations can be made to various aspects of the described embodiments. Accordingly, the described aspects are intended to embrace all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.

[0771] In this specification and the claims that follow, unless the context requires otherwise, the term "comprising", and variations such as "comprises" and "comprising", will be understood to mean including the stated integer or step or group of integers or steps, but not including any other integer or step or group of integers or steps.

[0772] Any reference in this specification to any prior publication (or information derived therefrom) or to any matter which is known is not, and should not be taken to be, an admission or acknowledgment or permission, or any kind of implication, that the prior publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. A method for surface disinfection, characterized in that, Contacting a surface with an iron-iron oxide composition; An iron-iron oxide composition comprising: a) a cashew seed coat extract; and b) iron-iron oxide core-shell particles, wherein the core is a metallic iron core or an iron alloy core and the shell is an iron oxide shell; Water is used as a solvent in the preparation process of the cashew seed coat extract; The cashew seed coat extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p-coumaric acid, gallic acid, or combinations thereof; And The iron-iron oxide particles are at least partially passivated by components of the cashew shell extract.

2. The method for surface disinfection according to claim 1, characterized in that The iron-iron oxide composition provides at least a 2 log reduction in microbial activity after 5 minutes.

3. The surface disinfection method according to claim 1, characterized in that The method further comprises the step of applying the iron-iron oxide composition to an application medium before (a); the application medium is selected from textiles, plastics, and cellulose products.

4. A composite material, characterized in that, It comprises a porous fabric impregnated with an iron-iron oxide composition and coated with a waterproof coating on at least one side of the porous fabric, An iron-iron oxide composition comprising: a) a cashew seed coat extract; and b) iron-iron oxide core-shell particles, wherein the core is a metallic iron core or an iron alloy core and the shell is an iron oxide shell; Water is used as a solvent in the preparation process of the cashew seed coat extract; The cashew seed coat extract comprises components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechins, p-coumaric acid, gallic acid, or combinations thereof; and The iron-iron oxide particles are at least partially passivated by components of the cashew shell extract; The iron-iron oxide composition is present in an amount of 0.1 wt% to 5 wt% relative to the composite material; and The thickness of the waterproof coating is 10 μm to 500 μm.

5. The composite material according to claim 4, characterized in that, The porous fabric is a fabric comprising cotton and spandex; Cotton is 90 wt% relative to the fabric; and Spandex is 10 wt% relative to the fabric.

6. The composite material according to claim 4 or 5, characterized in that, The iron-iron oxide composition comprises iron, iron(II) oxide, and iron(III) oxide.

7. The composite material according to claim 4, wherein The iron-iron oxide composition comprises elemental Fe, Fe3O4, and amino acids, carbohydrates, or mixtures thereof.

8. The composite material according to claim 7, characterized in that, The amino acids are selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, aspartic acid, glutamine, glutamic acid, lysine, arginine, histidine, and combinations thereof; The carbohydrates are selected from glucose, galactose, fructose, xylose, sucrose, lactose, maltose, trehalose, sorbitol, mannitol, maltodextrin, raffinose, stachyose, fructooligosaccharides, amylose, amylopectin, modified starch, glycogen, cellulose, hemicellulose, ethyl cellulose, methyl cellulose, pectin, and combinations thereof.

9. The composite material according to claim 4, wherein The particle size of the iron-iron oxide composition is 1 μm to 800 μm.

10. The composite material according to claim 4, wherein The thickness of the shell is 50 nm to 400 nm.

11. The composite material according to claim 4, wherein The iron-iron oxide particles are also at least partially passivated by a carboxylic acid moiety or a hydroxyl moiety.

12. The composite material according to claim 4, wherein The shell also contains components from the cashew seed coat extract.

13. The composite material according to claim 4, wherein The thickness of the shell is from 5 nm to 1 μm.

14. The composite material according to claim 4, characterized in that, Wherein, relative to the iron - iron oxide composition, the iron content is 20 wt% to 80 wt%, and relative to the iron - iron oxide composition, the oxygen content is 15 wt% to 40 wt%.

15. The composite material according to claim 4, wherein Wherein, relative to the iron - iron oxide composition, the carbon content of the iron - iron oxide composition is 4 wt% to 50 wt%.

16. The composite material according to claim 4, wherein The iron - iron oxide composition further contains excipients selected from stabilizers, dispersants, colorants, or combinations thereof.

17. The composite material according to claim 4, characterized in that Wherein the waterproof coating is selected from perfluorobutanesulfonic acid, perfluorooctanoic acid, perfluorohexanoic acid, Scotchgard, perfluorooctanesulfonic acid, paraffin, silica nanoparticles, and silanes.

18. A method for manufacturing a composite material, characterized in that, It includes: a) impregnating a porous fabric with an iron - iron oxide composition; and b) coating the porous fabric on at least one side with a waterproof coating to form a composite material, An iron - iron oxide composition, comprising: a) a cashew seed coat extract; and b) iron - iron oxide core - shell particles, the core being a metallic iron core or an iron alloy core, and the shell being an iron oxide shell; Water is used as a solvent in the preparation process of the cashew seed coat extract; Wherein the cashew seed coat extract contains components selected from proteins, amino acids, sugars, phenolic compounds, or combinations thereof, and the phenolic compounds are selected from tannins, catechins, epicatechins, epigallocatechin, p - coumaric acid, gallic acid, or combinations thereof; and The iron - iron oxide particles are at least partially passivated by the components of the cashew shell extract; Wherein, relative to the composite material, the iron - iron oxide composition is present in an amount of 0.1 wt% to 5 wt%; The thickness of the waterproof coating is from 10 μm to 500 μm.

19. A face mask, characterized in that, It includes: a) a facial covering structure configured to at least cover the mouth and nasal passages of the user; And b) a connecting structure, which includes: i) drawstrings connected to opposite sides of the facial covering structure, which are used to fix the facial covering structure to the user's face; and ii) a fastener releasably connected to the drawstrings to hold the drawstrings in a tightened position or a loosened position; Wherein the drawstrings are arranged to form an earband for surrounding behind the corresponding ears of the user and a neckband for surrounding behind the user's neck; Wherein the fastener is connected to the neckband; and Wherein the facial covering structure contains the composite material according to any one of claims 4 to 17.

20. The face mask according to claim 19, wherein Wherein the fastener is a cord lock.

21. The face mask according to claim 19 or 20, characterized in that, Wherein each earband includes a drawstring portion that is connected at a first point on one opposite side and passes through a connecting ring at a second point spaced apart from the first point.

22. The face mask according to claim 21, characterized in that, Wherein the neckband includes a drawstring portion spanning between the respective connecting rings.

23. The face mask according to claim 20, characterized in that, Wherein the drawstring passes through the eyelet of the cord lock.

24. The face mask according to claim 19, characterized in that, Wherein the facial covering structure includes a nose pad on its inner surface.

25. The face mask according to claim 19, characterized in that, Wherein the facial covering structure includes a filter layer.

26. The face mask according to claim 25, wherein, Wherein the filter layer is sandwiched between an outer fabric layer and an inner fabric layer.

27. The face mask according to claim 26, characterized in that, Wherein the outer fabric layer is the composite material according to any one of claims 4 to 17.

28. The face mask according to claim 25, characterized in that, Wherein the filter layer is replaceable.

29. The face mask according to claim 25, wherein, Wherein the facial covering structure includes a sleeve portion for accommodating the filter layer.

30. The face mask according to claim 19, characterized in that, Wherein the facial covering structure is configured to at least partially cover the submental triangle area of the user.

31. The face mask according to claim 30, characterized in that, The facial covering structure further includes a lower fabric, which is connected to the longitudinal sides of the outer fabric layer and the inner fabric layer and is away from the nose pad, such that when in use, the lower fabric is connected to the facial covering structure at an angle greater than 20°.

32. The face mask according to claim 19, wherein, The facial covering structure is configured to at least partially cover the zygomatic region of the user.

33. The face mask according to claim 32, characterized in that, The facial covering structure further includes two extensions, each of which extends from a first point on opposite sides of the facial covering structure and is for connecting to a drawstring.

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