Use of compositions comprising porous silica in preventing or inhibiting bacterial growth

Abstract

There is provided herein a composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm, in preventing or inhibiting bacterial growth.

Description

[0001] USE OF COMPOSITIONS COMPRISING POROUS SILICA IN PREVENTING OR INHIBITING BACTERIAL GROWTH

[0002] Field of the Invention

[0003] The present invention is concerned with uses of compositions containing porous silica particles in preventing or inhibiting bacterial growth. In particular, the present invention relates to the use of such compositions comprising porous silica particles as antibacterial agents which are functional in a variety of medical and non-medical uses, such as in wound healing.

[0004] Background to the Invention

[0005] The listing or discussion of any prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[0006] Bacterial infections are a significant global health concern, causing widespread morbidity and mortality. The emergence of antibiotic-resistant bacteria has further exacerbated the issue, leading to limited treatment options and challenging therapeutic interventions. The development of new and effective anti-bacterial agents is critical to addressing this growing problem and improving patient outcomes.

[0007] Anti-bacterial agents may serve to limit the risk of infection by preventing or reducing the growth of bacteria in areas that are in contact with a target of infection, such as humans. They may also serve to limit the effect of an infection by preventing or limiting growth at points of access to the body, such as site of a wound, and at the site of an infection.

[0008] The search for potent and safe anti-bacterial agents has led to extensive research in the field of biotechnology and pharmaceutical sciences. Various approaches have been explored, such as modifying existing antibiotics, identifying new natural compounds with antimicrobial properties, and harnessing advanced nanotechnology for targeted drug delivery.

[0009] So that they may establish and grow a population, bacteria require access to a food source. Such food sources may include biological material, such as tissue and biological fluids. However, in order to access the nutritional value in such materials, bacteria must first degrade and, at least partially, digest the material. One strategy employed by bacteria to achieve this is the excretion of various enzymes and toxins into the relevant media.

[0010] Specifically, bacterial growth typically begins with an inoculum of bacteria in a nutrientrich environment. The bacteria begin to grow and a biofilm may be formed. As the bacterial population grows, they consume the available nutrients and start to produce waste products, including various toxins and enzymes, which themselves contribute to damaging the tissue of the host organism and the host's defence. The damaged host tissue provides fresh nutrients for the bacteria to continue to grow and the cycle of bacterial growth / tissue damage is thus perpetuated.

[0011] Bacteria excrete toxins and enzymes through various mechanisms, which play a crucial role in their survival, colonization, and pathogenesis. These substances can also be harmful to host cells and tissues, contributing to the development of infections and disease.

[0012] Exotoxins are proteins produced and secreted by certain bacteria. They are released into the surrounding environment or directly into the host's tissues. These toxins can target specific cell types and disrupt cellular processes, leading to damage or death of the host cells. Exotoxins may have various functions, such as inhibiting protein synthesis, disrupting cell membranes, or interfering with cellular signalling pathways.

[0013] Endotoxins, also known as lipopolysaccharides (LPS), are components of the outer membrane of Gram-negative bacteria. They are not actively secreted but are released when the bacterial cell undergoes lysis or destruction. Endotoxins can cause a strong immune response in the host, leading to inflammation and other systemic effects. The release of endotoxins is a significant factor in the pathogenesis of severe bacterial infections, such as septic shock.

[0014] Bacteria secrete various enzymes that facilitate their survival and enhance their ability to colonize host tissues. Some common examples of bacterial enzymes include proteases, lipases, and nucleases. Proteases can break down proteins, allowing bacteria to access nutrients from host tissues. Lipases help in breaking down fats, which aids in bacterial invasion and colonization. Nucleases can degrade nucleic acids, which can hinder the host's immune response. Tissue-infecting bacteria are a class of bacteria that can invade the tissue of a host organism and cause infections. They can infect a variety of tissues, including skin, muscle, bone, and organs such as the lungs, liver, and kidneys. Infections with tissueinfecting bacteria are a significant public health threat.

[0015] Examples of tissue-infecting bacteria include Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli.

[0016] Typically, tissue-infecting bacteria rely on virulence factors, such as toxins and enzymes, to cause damage to host tissues and evade the immune system. For example, S. aureus can produce toxins that damage host cells and tissues.

[0017] Staphylococcus aureus is a pathogenic bacterium that can cause a wide range of infections, both in humans and animals, which range from mild skin infections to lifethreatening conditions. Staphylococcus aureus can cause infections if it enters the body through a cut or a wound.

[0018] Methicillin-resistant Staphylococcus aureus (MRSA) is a type of Staphylococcus aureus that has developed resistance to many antibiotics, making it a major concern in healthcare setting. MRSA can cause a variety of infections, including skin infections, pneumonia, and bloodstream infections.

[0019] In order to address the public health risk of infections, such as bacterial infections with tissue-infecting bacteria, there is a need to provide further methods of inhibiting the growth of such bacteria; in particular, methods of inhibiting their growth on various surfaces that are areas of human contact, as well as preventing and inhibiting their growth in sites of potential infection, such as wounds.

[0020] Porous silica particles have been used in a number of healthcare applications, such as in providing a medium for drug loading and delivery of therapeutic agents. They are thermally and chemically stable, and are exclusively composed of pure silicon dioxide.

[0021] Such silica particles may possess controllable pore sizes, which gives them a high surface area and large total pore volume. These properties, amongst others such as stability and biocompatibility, make them particularly suited for biomedical applications (see, for example, Wang, Y. et al., Nanomedicine Nanotechnology, Biol. Med. 11, 313- 327 (2015)). Moreover, similar materials have previously been approved as food additives (European Center for Ecotoxicology and Toxicology of Chemicals Synthetic Amorphous Silica (CAS No. 7631-86-9), JACC No. 51, page 14 (ECETOC, 2006)).

[0022] WO 2014 / 072363 discusses the use of highly structured, porous silica materials having a specific average pore size of pores in the mesoporous range in the treatment of conditions such as obesity and dyslipidemia. It does not provide any teaching relating to preventing or inhibiting bacterial growth.

[0023] Summary of the Invention

[0024] In a first aspect of the invention, there is provided the use of a composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm, in preventing or inhibiting bacterial growth.

[0025] In a second aspect of the invention, there is provided a method of preventing or inhibiting bacterial growth comprising contacting the bacterial growth medium with a composition as described in the first aspect of the invention.

[0026] In a third aspect of the invention, there is provided a composition as described in the first aspect of the invention, for use in:

[0027] (a) the prophylaxis or treatment of a bacterial infection; or

[0028] (b) inducing and / or accelerating the healing process of a wound.

[0029] In a fourth aspect of the invention, there is provided the use of a composition as described in the first aspect of the invention, in:

[0030] (a) the prophylaxis or treatment of a bacterial infection; or

[0031] (b) inducing and / or accelerating the healing process of a wound.

[0032] In a fifth aspect of the invention, there is provided a method for the prophylaxis or treatment of a bacterial infection comprising administering to a patient in need thereof a therapeutically effective amount of a composition as described in the first aspect of the invention.

[0033] In a sixth aspect of the invention, there is provided a method of inducing and / or accelerating the healing process of a wound by administering to the wound area a therapeutically effective amount of a composition as described in the first aspect of the invention. In a seventh aspect of the invention, there is provided a wound healing article comprising porous silica particles as described in the first aspect of the invention.

[0034] In an eighth aspect of the invention, there is provided the use of a composition as described in the first aspect of the invention, as a wound healing article.

[0035] Brief Description of the Figures

[0036] Figure 1 shows a nitrogen sorption analysis, displaying adsorption-desorption isotherms of the different types of silicas described in Example 1.

[0037] Figure 2 A-C shows nitrogen sorption analysis, displaying pore size distributions derived from the adsorption curve using the DFT model of the different types of silicas described in Example 1.

[0038] Figure 3 shows SEM micrographs of Silica 1.

[0039] Figure 4 shows levels of adsorbed bacterial a-toxin by Silica 2 and Silica 1.

[0040] Figure 5 shows levels of adsorbed bacterial lipase by Silica 2 and Silica 1.

[0041] Figure 6 shows levels of adsorbed bacterial a-toxin by Silica 3 and Silica 1.

[0042] Figure 7 shows levels of adsorbed bacterial lipase by Silica 3 and Silica 1.

[0043] Figure 8 shows a representative Western blot image displaying the levels of LT toxin subunits in both the pellet (pel) and supernatant (sup) fractions for Silica 1, Silica 2, Silica 3, the No-silica control. The upper band corresponds to Subunit A and the lower band corresponds to Subunit B.

[0044] Figure 9 shows levels of LT toxin subunit A adsorbed by Silica 1, Silica 2, and Silica 3.

[0045] Figure 10 shows levels of LT toxin subunit B adsorbed by Silica 1, Silica 2, and Silica 3.

[0046] Figure 11 shows the number of E. coli colonies formed following the treatment with Silica 1, Silica 2, and Silica 3. It is expressed as colony forming units per mL (CFU / mL). Detailed Description of the Invention

[0047] We have found that certain porous silica materials having a specific average pore size in the mesoporous range are able to effectively act as molecular sieves for certain biological molecules in a wide variety of settings, and thus have properties rendering them useful in the prevention or inhibition of bacterial growth, such as for disinfecting surfaces, reducing bacterial growth in a liquid or semi-liquid composition, and for preventing or inhibiting bacterial growth in or on living organisms, such as in wound healing.

[0048] Specifically, porous silica particles according to the present invention are designed to possess certain physiochemical properties, as herein described, allowing for a significant biological effect of relevance to the above-mentioned applications. Control of certain particle properties, such as average pore size, has been unexpectedly found to provide these biological effects, such as by allowing for the adsorption of certain toxins (such as a-toxin) and enzymes (such as lipase) which are released by certain bacteria (e.g. tissue-infecting bacteria) upon infecting the host tissue. Interfering with these toxins and enzymes (e.g. by adsorbing them) may lead to preventing or reducing the damage to the host's tissue, and a reduction in the amount of nutrients which would otherwise be available to the bacteria, essentially interrupting the bacterial growth cycle.

[0049] Without wishing to be bound by theory, the average pore size of the silica particles in the mesoporous range is important, as the pores must be of a suitably large enough size to be able to adsorb the relevant toxins and / or enzymes (such as a-toxin or lipase); however the pores must not be too large, otherwise other (e.g. larger) molecules could be adsorbed into the pores, which may quickly lead to saturation of the silica pores (which would then no longer be available to adsorb the bacterial toxins or enzymes of interest).

[0050] Uses and methods

[0051] Accordingly, in a first aspect of the invention there is provided the use of a composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm, in preventing or inhibiting bacterial growth. Unless indicated otherwise, all technical and scientific terms used herein will have their common meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0052] The skilled person will understand that references to preventing or inhibiting bacterial growth will refer to preventing or inhibiting the growth of bacteria.

[0053] For the avoidance of doubt, the silica particles as defined in the first aspect of the invention (including all embodiments and features thereof) may also be referred to as "the silica (or silica material or silica particles) of the invention (or of the first aspect of the invention)," or the like. Similarly, compositions as defined in the first aspect of the invention (including all embodiments and features thereof) may also be referred to as "the composition(s) of the invention (or of the first aspect of the invention)," or the like.

[0054] When used herein in relation to a specific value (such as an amount), the term "about" (or similar terms, such as "approximately") will be understood as indicating that such values may vary by up to 10% (particularly, up to 5%, such as up to 4%, 3%, 2% or 1%) of the value defined. It is contemplated that, at each instance, such terms may be replaced with the notation "±10%", or the like (or by indicating a variance of a specific amount calculated based on the relevant value). It is also contemplated that, at each instance, such terms may be deleted.

[0055] For the avoidance of doubt, the skilled person will understand that where percentages of a certain feature are defined as belonging to different (i.e. non-overlapping) groups, the sum of these percentages cannot exceed 100%. Similarly, where it is possible for such features to belong to other, non-specified groups, there is no requirement for the sum of the specified features to equal 100%.

[0056] The skilled person will understand that the porous silica particles as defined in the compositions of the first aspect of the invention may be referred to as a plurality thereof, which plurality may be referred to as a porous silica material.

[0057] As used herein, the term "inhibiting bacterial growth" includes achieving a reduction in the rate of bacterial growth, which may be referred to as a statistically significant reduction. In certain embodiments, there is at least a 1% reduction in the rate of bacterial growth, such as at least a 5%, 10% or 15% reduction, e.g. at least a 20% reduction).

[0058] The compositions of the invention (e.g. compositions as defined in the first aspect of the invention) may be considered antibacterial, such as bactericidal and / or bacteriostatic.

[0059] For example, in particular embodiments, the antibacterial effect is bacteriostatic.

[0060] In more particular embodiments, the use is bactericidal and bacteriostatic.

[0061] In particular embodiments, the bacterial growth is on a surface.

[0062] In particular embodiments, the surface is solid or semi-solid, such as solid.

[0063] The skilled person will understand that the surface may be a non-living surface or a living surface (e.g. living tissue).

[0064] In particular embodiments, the surface is a non-living surface, such as metal, plastic, wood, glass, leather, fabric, or the like.

[0065] In particular embodiments, the surface is an area in human contact, such as a surface that frequently comes into contact with human hands during normal use. The area in human contact may be a household, industrial, or a clinical (e.g. hospital) area.

[0066] In particular embodiments, the area in human contact is a clinical (e.g. hospital) area.

[0067] In particular embodiments, the area in human contact is furniture or a handle.

[0068] In more particular embodiments, the furniture is a tabletop (i.e. a work surface), seating (e.g. a chair or bench) or a bed.

[0069] In more particular embodiments, a handle may be a door handle or a handrail.

[0070] In particular embodiments, the area in human contact is a material, such as a covering material (e.g. a disposable covering, such as may be formed by tissue or paper). In particular embodiments, the covering material is clothing, such as shirts, scrubs, disposable patient gowns or lab coats.

[0071] In further embodiments, the covering material is a packaging material, such as food packaging, medicine packaging or equipment (such as medical equipment) packaging.

[0072] In even more particular embodiments, the covering material is food packaging.

[0073] In more particular embodiments, the covering material is a sanitary product, such as an absorbent pad.

[0074] In more particular embodiments, the covering material is a disposable covering, such as disposable paper covering (such as a covering for a tabletop, chair or bed).

[0075] In particular embodiments, where the area of human contact is a material, the silica particles may be embedded in or applied to the material.

[0076] For example, in certain embodiments the silica particles are embedded in the material, such as a paper covering, e.g. a disposable paper covering. In such embodiments, the silica particles may be incorporated into the material during manufacture.

[0077] In particular embodiments, the surface is a medical tool (such as a surgical instrument) or a medical device (such as a medical implant).

[0078] In more particular embodiments, the medical tool is hospital room equipment, such as medical diagnostic equipment.

[0079] In more particular embodiments, the medical device is an analytical instrument or a patient handling device.

[0080] In further embodiments, the surface is a living tissue, such as an animal (e.g. mammal, such as human) body or part thereof.

[0081] In more particular embodiments, the living tissue is an external body part (i.e. outside of the animal body, e.g. human body). In more particular embodiments, the living tissue is external epithelial tissue, such as skin. In certain particular embodiments, the external body part does not include the head (i.e. a part of the body, internal or external, above the neck).

[0082] In certain embodiments, the external body part is not part of the oral cavity (including the mouth, teeth and gums).

[0083] In certain embodiments, the use excludes use in oral care (i.e. as an oral care product).

[0084] In more particular embodiments, the living tissue is a wound (i.e. a skin wound), such as an abrasion, burn, laceration, surgical incision, stab wound, open wound, chronic wound, traumatic wound, diabetic wound, dermatitis or ulcer.

[0085] In even more particular embodiments, the wound is an open wound, chronic wound, or traumatic wound.

[0086] In particular embodiments, the living tissue is internal (i.e. inside body, e.g. an internal organ).

[0087] In certain embodiments, the living tissue excludes the oral cavity and gastrointestinal (GI) tract.

[0088] In certain embodiments, the living tissue excludes the gastrointestinal (GI) tract.

[0089] In more particular embodiments, the internal living tissue comprises a wound, such as a surgical incision, open wound, chronic wound, traumatic wound, or ulcer.

[0090] In particular embodiments where the surface is a living tissue, the use in preventing or inhibiting bacterial growth is non-therapeutic (i.e. cosmetic), for example by promoting skin integrity.

[0091] In particular embodiments, the bacterial growth is in a semi-solid, liquid, cream, oil, or paste, such as semi-solid or liquid (e.g. a liquid).

[0092] In more particular embodiments, the semi-solid, liquid, cream, oil, or paste is a food item.

[0093] In more particular embodiments, the semi-solid, liquid, cream, oil, or paste is a cosmetic agent or a medicament. In even more particular embodiments, the cosmetic agent is an external cosmetic agent (i.e. the cosmetic agent is only suitable for use outside the animal body, e.g. the human body). For example, the cosmetic agent may be a face cream, body cream, hair product, a make-up product, or a skin-care product.

[0094] Similarly, in particular embodiments, the medicament is a medicament for external use (i.e. the medicament is only suitable for use outside the animal body, e.g. human body). For example, the medicament may be suitable for topical application, such as a medicament for treating a skin condition.

[0095] In particular embodiments, where the bacterial growth is in a semi-solid or liquid, the semi-solid or liquid may be part of, or produced by, a wound.

[0096] According to the second aspect of the invention, there is provided a method of preventing or inhibiting bacterial growth comprising contacting the bacterial growth medium using a composition as described in the first aspect of the invention.

[0097] According to the third aspect of the invention there is provided a composition as defined in the first aspect of the invention (including all embodiments thereof), for use in:

[0098] (a) the prophylaxis or treatment of a bacterial infection; or

[0099] (b) inducing or accelerating the healing process of a wound.

[0100] As used herein, the term prevention (and, similarly, preventing) will include references to the prophylaxis of a condition (and vice-versa). In particular, such terms term may refer to achieving a reduction (for example, at least a 10% reduction, such as at least a 20%, 30% or 40% reduction, e.g. at least a 50% reduction) in the likelihood of a subject developing the condition.

[0101] For the avoidance of doubt, the skilled person will understand that such uses and methods will be performed in a subject in need thereof. The need of a subject for such uses and methods may be assessed by those skilled the art using routine techniques.

[0102] As used herein, references to a subject will refer to a living subject being treated, including mammalian (e.g. human) patients. In particular, references to a subject will refer to human, such as a human of adult age (i.e. a human aged 18 years or over). In alternative embodiments, references to a patient may refer to other mammals, such as livestock (e.g. cattle, pigs, sheep, goats, horses, and the like) and / or household pets (e.g. cats, dogs, rabbits, and the like).

[0103] The skilled person will understand that uses and methods relating to the composition of the invention (e.g. a composition defined in the first aspect of the invention) may further comprise such steps as may be appropriate for its use in the form provided.

[0104] In some embodiments, the patient has, or is vulnerable to, a condition characterised by immunosuppression, such as chemotherapy and or radiation induced immunosuppression.

[0105] In particular embodiments, the tissue is external (i.e. outside of to the animal body e.g. human body). In more particular embodiments, the tissue is external epithelial tissue, such as skin.

[0106] In alternative embodiments, the tissue is internal (i.e. inside the animal body e.g. human body). In particular embodiments, the tissue is internal epithelial tissue.

[0107] As used herein, references to an animal include a mammal, such as a human.

[0108] As explained above, the compositions of the invention (e.g. compositions as defined in the first aspect of the invention) may possess antibacterial (such as bacteriostatic and / or bactericidal) properties. As such, they may allow for the prophylaxis or treatment of a bacterial infection per se, that is treatment of a bacterial infection (or a bacterial disease) by interfering with bacterial growth or proliferation in (or on) a host tissue, as opposed to the treatment of any symptoms of bacterial infection, such as pain and / or inflammation. The compositions of the invention may therefore be considered to be antibacterial.

[0109] Similarly, by virtue of the anti-bacterial effects as described herein, compositions of the invention may allow for the prophylaxis or treatment of diseases and disorders that may result from a bacterial infection, such as inflammation, sepsis, tissue necrosis (e.g. gangrene), and the like.

[0110] For example, compositions of the invention may allow for the prophylaxis or treatment of inflammation (i.e. inflammation caused by bacterial infection, such as bacterial arthritis). As such, in particular embodiments, the composition of the third aspect of the invention is for use in treating a bacterial infection.

[0111] In more particular embodiments, the bacteria causing the bacterial infection are tissueinfecting bacteria.

[0112] The antibacterial properties may also allow for the prevention of the onset of a bacterial infection or disease, the protection of cells in a host from (e.g. further) bacterial infection, prevention or arrest of the spread of bacterial infection or disease (within a single host, or from one host to a new host), or for the prevention of reactivation of a bacterium after latency in a host.

[0113] As such, in particular embodiments, the composition of the third aspect of the invention is for prophylaxis (or prevention) of a bacterial infection.

[0114] In more particular embodiments, the bacteria causing the bacterial infection are tissueinfecting bacteria.

[0115] In particular embodiments, the bacterial infection is in point of access to the body, which may be referred to as a site of potential infection.

[0116] In more particular embodiments, the bacterial infection is in a wound.

[0117] In particular embodiments, the composition of the third aspect of the invention is for inducing or accelerating the healing process of a wound.

[0118] For the avoidance of doubt, the third aspect of the invention may have any of the features described for the first, second and fourth to eighth aspects of the invention.

[0119] Thus, for the avoidance of doubt, in more particular embodiments, the wound is external (i.e. outside of the animal body e.g. human body). In alternative embodiments, the wound is internal (i.e. inside the animal body e.g. human body).

[0120] In more particular embodiments, the wound is selected from the group consisting of an abrasion, burn, cut, laceration, surgical incision, stab wound, bullet wound, open wound, chronic wound, traumatic wound, diabetic wound, dermatitis and ulcer. In yet more particular embodiments, the wound is selected from an open wound, chronic wound and / or traumatic wound.

[0121] According to the fourth aspect of the invention, there is provided the use of a composition as defined in the first aspect of the invention (including all embodiments thereof) in :

[0122] (a) the prophylaxis or treatment of a bacterial infection; or

[0123] (b) inducing or accelerating the healing process of a wound.

[0124] In particular embodiments, the use is in the prophylaxis (or prevention) of a bacterial infection (such as infection with a tissue-infecting bacteria).

[0125] In particular embodiments, the use is in the treatment of a bacterial infection (such as infection with a tissue-infecting bacteria).

[0126] In particular embodiments, the use is in inducing or accelerating the healing process of a wound.

[0127] In an alternative fourth aspect of the invention, there is provided the use of a composition as defined in the first aspect of the invention (including all embodiments thereof), for the manufacture of a medicament for the prophylaxis or treatment of a bacterial infection.

[0128] For the avoidance of doubt, the fourth aspect of the invention may have any of the features described for the first to third and fifth to eighth aspects of the invention.

[0129] According to the fifth aspect of the invention, there is provided a method of prevention (or prophylaxis) or treatment of an infection with bacteria, in a subject in need thereof, comprising the step of using (or administering / applying, such as to a wound) a therapeutically effective amount of a composition as defined in the first aspect of the invention (including all embodiments thereof).

[0130] For the avoidance of doubt, the fifth aspect of the invention may have any of the features described for the first to fourth and sixth to eighth aspects of the invention.

[0131] According to the sixth aspect of the invention, there is provided a method of inducing or accelerating the healing process of a wound by administering to the wound area a composition comprising a therapeutically effective amount of a composition as defined in the first aspect of the invention (including all embodiments thereof).

[0132] For the avoidance of doubt, the sixth aspect of the invention may have any of the features described for the first to fifth, seventh and eighth aspects of the invention.

[0133] Compositions

[0134] The skilled person will appreciate that compositions of the invention as described herein may take a variety of forms, depending on factors such as the medium to which the composition is to be applied / administered.

[0135] In some embodiments, the compositions of the invention may be in the form of a solution or suspension, cream, gel, ointment, emulsion, spray (e.g. a film-forming spray), powder, paste, liquid, gum, serum, or a dressing (such as a patch or pad).

[0136] For example, when applied to a surface, compositions of the invention may be in the form of a liquid (e.g. a solution or suspension), cream, gel, spray (e.g. a film-forming spray) or powder.

[0137] The skilled person will understand that references to gels may refer to substances having the physical properties of a liquid but with substantially zero flow.

[0138] In certain embodiments, the composition of the invention is not an oral care composition (i.e. is not for use in oral care).

[0139] In certain embodiments, the compositions of the invention are not a dentifrice (such as toothpaste or toothpowder) or mouthwash.

[0140] In particular embodiments, the compositions of the invention may be referred to as being non-systemic, topical (e.g. for topical application to a wound). As such, the compositions of the invention may be for external use (i.e. external animal body use).

[0141] In alternative embodiments, the compositions of the invention may be for internal use (i.e. internal animal body use). The compositions of the invention may comprise additional components as typically present in the relevant type of composition, which components will be known to those skilled in the art.

[0142] In particular embodiments, the composition of the invention is substantially free of surfactant.

[0143] As used herein, the skilled person will understand that the reference to being substantially free of surfactant may refer to presence of components classified as surfactants (such as those referred to herein) at concentrations at or below about 0.5 wt% of the total composition, such as at or below about 0.4, 0.3, 0.02 or, particularly, 0.1 wt% of the total composition (e.g. at or below about 0.09, 0.08, 0.07, 0;06 or 0.05 wt% of the total composition, particularly below about 0.04, 0.03, 0.02 or 0.01 wt% of the total composition).

[0144] In particular embodiments, the skilled person will understand that the reference to being substantially free of surfactant may refer to the absence of (i.e. the absence of detectable levels of) components classified as surfactants, which may indicate that the preparation of such compositions does not involve addition of any such components.

[0145] As used herein, being substantially free of a component may be indicated by stating that the composition "does not contain a substantial concentration of" or "does not contain" that component, respectively.

[0146] The skilled person will also understand that the maximum about of surfactant that may be present may vary depending on the nature of the surfactant component, with such levels being determined using routine techniques.

[0147] For example: in respect of anionic surfactants, such as sodium lauryl sulfate, the surfactant may be present at levels at or below about 0.05 wt% (e.g. below about 0.04, 0.03, 0.02 or, particularly, 0.01 wt%), or may be referred to in terms of the absence thereof; in respect of zwitterionic (zero net charge) surfactants, such as cocamidopropyl betaine, the surfactant may be present at levels at or below about 0.05 wt%; nonionic surfactants, such as polyethoxylated fatty acid sorbitan esters (e.g. polysorbate 80), the surfactant may be present at levels at or below about 0.1 (or, particularly, 0.05) wt%, or may be referred to in terms of the absence thereof.

[0148] In particular embodiments, where amounts of specific surfactants are referred to, compositions will be substantially free of other surfactants.

[0149] The skilled person will understand that the compositions of the invention may be provided in the form of a mixture of the various components thereof. In particular, the skilled person will understand that such mixtures may comprise components in both the liquid (or gel) and solid phases (e.g. as solid particles), in which case in use the solid component(s) may be substantially evenly distributed through the liquid (or gel) components, which in the case of liquid compositions may require the composition to be agitated (e.g. shaken) before use.

[0150] For the avoidance of doubt, in the case of liquid compositions, the silica particles may be heterogenous with the liquid composition, resulting in sedimentation of the particles during storage. Thus, use of the composition may require mixing (e.g. by shaking and / or inversion thereof) prior to use.

[0151] For the avoidance of doubt, the skilled person will understand that references herein to particles forming part of a composition may include only particles of a suitable size to be considered as forming part of the composition (i.e. particles that may be able to function as a component of the composition).

[0152] The skilled person will be able to determine the amount of the silica of the invention required in compositions of the invention in order to provide the effects as described herein, which amounts may depend on the type of composition used.

[0153] In particular embodiments, the silica of the invention may be present in compositions of the invention in amounts from about 0.1 to about 90.0 wt%.

[0154] For example, the silica of the invention may be present in compositions of the invention in amounts from about 0.1 to about 80.0, 70.0, 60.0, 50.0, 40.0 or 30.0 wt%.

[0155] In particular embodiments, the silica of the invention may be present in compositions of the invention in amounts from about 0.1 to about 20.0 wt%. As used herein, the term "consists essentially of" may indicate that the relevant composition consists of at least 90% by weight (e.g. at least 95% by weight, such as at least 99% by weight or, particularly, at least 99.9%) of the relevant substance.

[0156] In certain embodiments of the first aspect of the invention, the composition of the invention consists (or consists essentially of) the porous silica particles as defined herein (i.e. a plurality of such particles).

[0157] In alternative embodiments of the first aspect of the invention, the porous silica particle content (or, alternatively, the silica particle content) of the composition consists of (or consists essentially of) the silica particles as defined herein (i.e. such that components other than porous silica material may be present).

[0158] The skilled person will understand that the properties of the silica of the invention may be such that the use of other toxin adsorbing materials / substances and / or enzyme adsorbing materials / substances and / or antibacterial agents is not required (i.e. the composition of the invention may produce the effects as described herein without the need for the presence of such agents).

[0159] In particular embodiments, wherein the use of the composition is a therapeutic use, the composition of the invention may be able to deliver a therapeutic effect per se. Treatment with such composition may therefore be therapeutically effective even in the absence of treatment with any other therapeutic agent(s). As such, in particular embodiments, the use does not comprise administration in combination with other therapeutic agents.

[0160] Similar, the skilled person will understand that, as the porous silica particles are therapeutically active, the inclusion of other therapeutic agents in compositions (including pharmaceutical compositions) as described herein is optional.

[0161] In particular embodiments, the composition comprises the porous silica material (as defined in the first aspect of the invention) as the only (i.e. sole) therapeutically active ingredient.

[0162] Thus, in further embodiments, the composition is substantially free of other therapeutically active ingredients. As used herein in relation to other therapeutically active ingredients, the term substantially free will refer to the essential material (e.g. the composition referred to) comprising no significant (i.e. clinically significant) amount of the other material referred to (e.g. the other therapeutically active ingredient(s)), which may indicate the presence of less than 10% (e.g. less than 5%, such as less than 2%, less than 1%, less than 0.5% or, particularly, less than 0.1%, less than 0.01% or less than 0.001%) by weight of the other material, or more particularly the presence of no detectable amount of the other material.

[0163] In certain embodiments, the porous silica particles are not loaded with (i.e. do not have adsorbed, e.g. adsorbed in the pores thereof) a therapeutic agent.

[0164] In particular embodiments of the first aspect of the invention, the composition comprises the porous silica material (as defined in the first aspect of the invention) as the only (i.e. sole) ingredient capable of adsorbing a toxin and / or enzyme released by the bacteria (such as by tissue-infecting bacteria).

[0165] Thus, in further embodiments of the first aspect of the invention, the composition is substantially free of other toxin and / or enzyme adsorbing ingredients.

[0166] As used herein in relation to toxin and / or enzyme adsorbing ingredients, the term substantially free will refer to the essential material (e.g. the composition referred to) comprising no significant (i.e. clinically significant) amount of the other material referred to (e.g. the other therapeutically active ingredient(s)), which may indicate the presence of less than 10% (e.g. less than 5%, such as less than 2%, less than 1%, less than 0.5% or, particularly, less than 0.1%, less than 0.01% or less than 0.001%) by weight of the other material, or more particularly the presence of no detectable amount of the other material.

[0167] Porous silica particles

[0168] The skilled person will understand that references herein to pores being of a certain size will refer to the average diameter of the relevant pores (i.e. the average diameter of each individual pore, considering the dimensions thereof). For the avoidance of doubt, the skilled person will understand that references to average pore size may refer in particular to the average size of the opening of each pore (or, in the case of a pore the channel of which internally traverses the body of the particle, the average size of all openings to the pore(s)), which may be referred to as the pore window(s) (or the window(s) of the pore).

[0169] For the avoidance of doubt, unless otherwise stated, averages referred to herein will be calculated as the mean average.

[0170] Unless otherwise stated, pore sizes as described herein is measured by nitrogen sorption and calculated using the Density Functional Theory (DFT) method (see, for example, the methods as described in Landers, J. et al., Colloids and Surfaces A: Physicochem. Engineering Aspects, 437, 3-32 (2013)). As such, unless otherwise stated, references herein to an average pore size will refer to pore size as measured by nitrogen sorption and calculated using the Density Functional Theory (DFT).

[0171] The skilled person will understand that references to the percentage of pores present being in a particular range may be understood to be references to the pore size distribution (PSD) of such particles. As such, references to the percentage of pores present being in a particular range will refer to the combined volume of pores present in each range as a percentage of the total pore volume of the relevant group(s) of pores (e.g. pores in the mesoporous range).

[0172] For the avoidance of doubt, references to particles having a particular average pore size may in certain instances include references to pores that are functionally equivalent (e.g. when utilised in the manner described herein) with particles having such average pore sizes.

[0173] The skilled person will understand that pore size distribution of the silica material may be measured using DFT pore size distribution curves, which is a technique well- understood by those skilled in the art (see, for example, Olivier, J. P., Conklin, W. B. and Szombathely, M. V., Studies in Surface Science and Catalysis, 87, 81-89 (1994)). The percentage of the pores are calculated from the DFT cumulative pore size distribution curves.

[0174] The skilled person will understand that references to porous silica particles having pores in the mesoporous range will take its normal meaning in the art, i.e. as referring to porous silica particles having (or containing / comprising) pores with a diameter in the range 2 to 50 nm, which materials may be referred to as mesoporous and which pores may be referred to as mesopores. For the avoidance of doubt, the skilled person will understand that the porous silica material referred to in the first aspect of the invention may also have (i.e. further containing / comprising) pores with a diameter outside of the mesoporous range, such as by having micropores (i.e. pores with a diameter of less than 2 nm) and / or macropores (i.e. pores with a diameter of greater than 50 nm).

[0175] For the avoidance of doubt, unless otherwise stated, references for percentages of pores as used herein will refer to the percentage by volume.

[0176] In a particular embodiment, at least about 40% (i.e. 40% by volume) of the pores present in the silica material of the invention are in the mesoporous range.

[0177] In a more particular embodiment, at least about 50%, such as at least about 60%, particularly at least about 70%, of the pores present in the silica material of the invention are in the mesoporous range.

[0178] The skilled person will understand that, in relation to the pores in a given range, there may also be calculated an average (i.e. mean average) pore size. As described herein, such average pore size may be measured by the nitrogen sorption technique and calculated using the Density Functional Theory (DFT), which will be well-known to those skilled in the art (see: Olivier, J. P., Conklin, W. B. and Szombathely, M. V., Studies in Surface Science and Catalysis, 87, 81-89 (1994); Landers, J., et al., Colloids and Surfaces A: Physicochem. Eng. Aspects, 437, 3-32 (2013)). As such, unless otherwise stated, references herein to average pore size will refer to average pore size as measured by nitrogen sorption and calculated using DFT.

[0179] In particular embodiments, the average pore size of the pores in the mesoporous range is from about 7.0 to about 22.0 nm.

[0180] In more particular embodiments, the average pore size of the pores in the mesoporous range is from about 7.0 to about 21.0 nm.

[0181] In yet more particular embodiments, the average pore size of the pores in the mesoporous range is from about 7.0 to about 20.0 nm.

[0182] For example, in certain embodiments the average pore size of the pores in the mesoporous range is at least about 7.0nm, such as: from about 7.0 to about 19.0 nm; from about 7.0 to about 18.0 nm; from about 7.0 to about 17.0 nm; from about 7.0 to about 16.0 nm; from about 7.0 to about 15.0 nm; from about 7.0 to about 14.0 nm; from about 7.0 to about 13.0 nm; or from about 7.0 to about 12.0 nm.

[0183] In certain embodiments, the average pore size of the pores in the mesoporous range is at least about 8.0nm, such as from about 8.0 to about 13.0 nm.

[0184] In more particular embodiments, the average pore size of the pores in the mesoporous range is from about 8.0 to about 12.0 nm.

[0185] In more particular embodiments, the average pore size of the pores in the mesoporous range is from about 8.0 to about 11.0 nm.

[0186] In alternative embodiments, the average pore size of the pores in the mesoporous range is at least about 9.0nm, such as from about 9.0 to about 11.0 nm.

[0187] In yet more particular embodiments, the average pore size of the pores in the mesoporous range is at least about lO.Onm, such as from about 10.0 to about 18.0 nm.

[0188] In yet more particular embodiments, the average pore size of the pores in the mesoporous range is at least about lO.lnm, such as from about 10.1 to about 18.0 nm.

[0189] In yet more particular embodiments, the average pore size of the pores in the mesoporous range is at least about 10.2nm, such as from about 10.2 to about 18.0 nm.

[0190] In certain embodiments, the average pore size of the pores in the mesoporous range is about 10.2 nm.

[0191] In certain embodiments, the average pore size of the pores in the mesoporous range is not 10 nm. In certain embodiments, the average pore size of all pores is not 10 nm.

[0192] The skilled person will understand that, in addition to referring to the (mean) average pore size, as described herein, the silica material of the invention may also be defined by reference to the distribution of pore sizes, such as the distribution of pore sizes of the pores in the mesoporous range.

[0193] In particular embodiments of the first aspect of the invention, at least 21% (such as at least at least 22%, at least 23%, at least 24%, at least 25%, at least 26%, at least 27% at least 28% or at least 29%) of the pores in the mesoporous range (by volume) have a diameter in within the range of the specified for the average pore size (i.e. the range as specified for the average pore size).

[0194] In more particular embodiments of the first aspect of the invention, at least about 30% of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0195] In yet more particular embodiments of the first aspect of the invention, at least about 35% (such as at least 40% or at least 45%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0196] In still more particular embodiments of the first aspect of the invention, at least about 50% (such as at least 55%, at least 60%, at least about 65%, at least about 70% or, particularly, at least about 72%) of the pores in the mesoporous range have a diameter in within the range of the average pore size (i.e. the range given for the average pore size of the pores in the mesoporous range, as defined herein).

[0197] For example, in certain embodiments at least about 50% (such as at least 55%, at least 60%, at least about 65%, at least about 70% or, particularly, at least about 72%) of the pores in the mesoporous range have a diameter in within the range specified for pores in the mesoporous range, such as in the range 7.0 to 25.0 nm, e.g. in the range 7.0 to 18.0 nm.

[0198] In certain embodiments, up to about 100% (or up to about 99%, about 95%, or about 90%) of the pores in the mesoporous range have a diameter in within the range of the average pore size (i.e. the average pore size range of pores in the mesoporous range as specified herein). In certain embodiments, from about 21% to about 100% (or, particularly, about 25% to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0199] In yet more particular embodiments of the first aspect of the invention, at least about 30% (e.g. about 30% to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0200] In yet more particular embodiments of the first aspect of the invention, at least about 35% (e.g. about 35% to about 99%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0201] In yet more particular embodiments of the first aspect of the invention, about 40% to about 90% (or to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0202] In certain embodiments of the first aspect of the invention, about 50% to about 90% (or to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0203] In certain embodiments of the first aspect of the invention, about 55% to about 90% (or to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0204] In certain embodiments of the first aspect of the invention, about 60% to about 90% (or to about 99% or 100%) of the pores in the mesoporous range have a diameter in within the range of the average pore size.

[0205] For example, in a particular embodiment (i.e. a particular embodiment of the first aspect of the invention), at least about 25% (e.g. about 25% to about 99%, such as about 50% to about 99% or 100%) of the pores of the silica particle are mesopores of a size in the range of from about 7.0 to about 25.0 nm (such as about 7.0 to about 18.0 nm, or about 7.0 to about 13.0 nm).

[0206] Similarly, in a particular embodiment, at least about 50% (e.g. about 50% to about 99%, such as about 50% to about 90%) of the pores of the silica particle are mesopores of a size in the range of from about 7.0 to about 25.0 nm (such as about 7.0 to about 18.0 nm, or about 7.0 to about 13.0 nm). In a particular embodiment (i.e. a particular embodiment of the first aspect of the invention), at least about 50% (e.g. about 50% to about 99%) of the pores of the silica particle are mesopores of a size in the range of from about 9.0 to about 12.0 nm.

[0207] In a further embodiment, at least about 25% (e.g. at least about 50%, about 60% or about 70%) of the pores of the silica particle are mesopores of a size in the range of from about 9.0 to about 18.0 nm.

[0208] In a further embodiment, at least about 25% (e.g. at least about 50%, about 55%, about 60%, about 65% or about 70%) of the pores of the silica particle are mesopores of a size in the range of from about 10.1 to about 18.0 nm.

[0209] In a more particular embodiment, at least about 25% (e.g. about 25% to about 99%) of the pores of the silica particle are mesopores of a size in the range of from about 10.1 to about 15.0 nm.

[0210] In a yet more particular embodiment, at least about 25% (e.g. about 25% to about 99%) of the pores of the silica particle are mesopores of a size of about 10.2 nm.

[0211] The skilled person will understand that references to porous silica particles having pores in the mesoporous range will necessarily require that such particles are porous, which will include particles behaving in a porous manner. As such, porous silica particles will refer to particles having a significant degree of porosity, which may in certain embodiments be defined by reference to features such as the pore volume and / or surface area of the particles, such as by reference to those parameters as defined herein (which features as described herein may, as with other features described herein, be taken both alone and in combination).

[0212] The skilled person will understand that the surface area of a particle (or a sample of particles) may be calculated using the Brunauer Emmett Teller (BET) theory, a technique well-known to those skilled in the art (see, for example, Brunauer, S., Emmett, P. H., and Teller, E., J. Am. Chem. Soc., 60(2), 309-319 (1938)).

[0213] In a particular embodiment, the silica particles have a BET surface area of at least about 150 m2 / g. In a more particular embodiment, the silica particles have a BET surface area of at least about 200 m2 / g.

[0214] In a yet more particular embodiment, the silica particles have a BET surface area of at least about 300 m2 / g (such as at least about 350 m2 / g).

[0215] In a still more particular embodiment, the silica particles have a BET surface area of at least about 400 m2 / g (such as at least about 450 m2 / g).

[0216] In a particular embodiment, the silica particles have a BET surface area of at least about 500 m2 / g.

[0217] In particular embodiments, the BET surface area is up to about 1500 m2 / g (such as up to about 1200 m2 / g or 1000 m2 / g).

[0218] For example, in a particular embodiment, the silica particles have a BET surface area of from about 200 to about 1500 m2 / g.

[0219] In a further embodiment, the silica particles have a BET surface area of from about 500 to about 1200 m2 / g.

[0220] In a yet more particular embodiment, the silica particles have a BET surface area of from about 600 to about 1200 m2 / g.

[0221] In an alternative embodiment, the silica particles have a BET surface area of from about 600 to about 1000 m2 / g.

[0222] In a further alternative embodiment, the silica particles have a BET surface area of from about 500 to about 900 m2 / g, such as from about 550 to about 900 m2 / g.

[0223] In a yet further alternative embodiment, the silica particles have a BET surface area of from about 600 to about 850 m2 / g.

[0224] The skilled person will understand that the porous silica particles may be provided in a variety of shapes.

[0225] In a particular embodiment, the silica particles have a substantially non-spherical morphology (i.e. an aspect ratio of greater than 1: 1, such as greater than 1.1: 1). In a more particular embodiment, the silica particles have an aspect ratio of greater than 1.5: 1, such as greater than 1.8: 1.

[0226] In a yet more particular embodiment, the silica particles have an aspect ratio equal to or greater than 2: 1.

[0227] As used herein, the term "aspect ratio" will be understood to refer to the ratio between the largest cross-section diameter of the silica particle and the smallest cross-section diameter.

[0228] Alternatively, such particles (i.e. particles having a substantially non-spherical morphology) may be described as having at least one plane (i.e. an equally dividing plane bisecting the particle) of asymmetry (i.e. such that the morphology of the particle differs about the plane).

[0229] In a more particular embodiment, the silica particles have an essentially rod-shaped morphology. Thus, in particular embodiments, the porous silica particle may be characterized by having an essentially rod-shaped morphology, as seen by electron microscopy (such as by Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM), using techniques known to those skilled in the art), such as with a rod-length of from about 0.5 to about 5.0 pm.

[0230] As used herein, the term essentially rod-shaped will be understood as referring to a particle of an elongate form resembling a rod, in which the rod may be straight or curved (e.g. such rod shaped particles may be substantially straight).

[0231] In an alternative embodiment, the silica particles of the invention may be substantially spherical (or referred to as spherical). Thus, in a particular embodiment, the silica particles of the invention may have an aspect ratio (or an average aspect ratio) of about 1 : 1.

[0232] In further embodiments, the silica particles of the invention may be of amorphous shape.

[0233] The skilled person will understand that the term mean particle size, as used herein, will refer to the mean diameter of the particles at the greatest point thereof (e.g. in the case of rod-shaped particles, the length thereof; or in the case spherical particles, the diameter thereof.), which may be measured using techniques well-known to those skilled in the art, for example using electron microscopy techniques (such as by Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) technique known to those skilled in the art). In a particular embodiment, particle size is determined using electron microscopy (e.g. using SEM).

[0234] In particular embodiments, such as those in which the particles are spherical, the size of particles may be defined by reference to the diameter thereof.

[0235] In a particular such embodiment, the silica particles have a mean particle size of from about 0.1 to about 20.0 pm.

[0236] In a more particular embodiment, the silica particles have a mean particle size of from about 0.1 to about 15.0 pm.

[0237] In a yet more particular embodiment, the silica particles have a mean particle size of from about 0.1 to about 10.0 pm.

[0238] In a yet more particular embodiment, the silica particles have a mean particle size of from about 0.5 to about 10.0 pm.

[0239] In a still more particular embodiment, the silica particles have a mean particle size of from about 0.5 to about 5.0 pm.

[0240] In certain embodiments, the silica particles have a mean particle size of from about 0.5 to about 4.5 pm.

[0241] In particular embodiments, the silica particles have a mean particle size of from about 1.0 to about 10.0 pm.

[0242] In particular embodiments, the silica particles have a mean particle size of from about 1.0 to about 5.0 pm.

[0243] In more particular embodiments, the silica particles have a mean particle size of from about 1.0 to about 4.0 pm.

[0244] In yet more particular embodiments, the silica particles have a mean particle size of from about 1.0 to about 2.0 pm. In still more particular embodiments, the silica particles have a mean particle size of at least 500 nm.

[0245] In further embodiments, such as those in which the particles are rod-shaped, the size of particles may be defined (or also defined) by reference to the width thereof (which will refer to the diameter at the narrowest point).

[0246] In a particular such embodiment, the silica particles have a mean width of from about 0.05 to about 0.6 pm.

[0247] In a more particular embodiment, the silica particles have a mean width of from about 0.1 to about 0.6 pm.

[0248] In a yet more particular embodiment, the silica particles have a mean width of from about 0.1 to about 0.4 pm.

[0249] In a yet more particular embodiment, the silica particles have a mean width of from about 0.2 to about 0.4 pm.

[0250] The skilled person will understand that porous silica materials of the type described in the present invention are typically non-crystalline. Thus, in certain embodiments, the porous silica particle may be described as a substantially non-crystalline porous silica particle (and materials formed from a plurality of such particles may be described in the same manner). As such, the porous silica particle may be described as a noncrystalline porous silica particle.

[0251] In alternative embodiments, the silica material present in particles as described in the first aspect of the invention may be described as being amorphous. In such embodiments, it will be understood that the term amorphous will indicate that the structure of the silica material (excluding the pores present therein) has no substantial order, such as the order which may be present in a crystalline substance (i.e. the porous silica particles, or silica material, may be referred to as non-crystalline).

[0252] As described herein, the skilled person will understand that the silica materials of the invention are porous. As such, silica particles of the invention may be referred to as having a certain minimum total pore volume, as measured using nitrogen sorption (e.g. taken as the volume adsorbed at the highest value of P / Po, for example, P / Po = 0.995), or a range of such volumes.

[0253] In particular embodiments, the total pore volume is at least about 0.2 cm3 / g (such as at least about 0.3, 0.4, 0.5, 0.6 or 0.7 cm3 / g).

[0254] In particular embodiments, the total pore volume is from about 0.2 to about 2.5 cm3 / g.

[0255] In more particular embodiments, the total pore volume is from about 0.2 to about 2.0 cm3 / g.

[0256] In yet more particular embodiments, the total pore volume is from about 0.5 to about 1.5 cm3 / g.

[0257] In still more particular embodiments, the total pore volume is from about 0.6 to about 1.4 cm3 / g.

[0258] For example, in certain embodiments, the total pore volume is from about 0.7 to about 1.3 cm3 / g.

[0259] Anti-bacterial properties

[0260] As described herein, the porous silica particles as described herein, and therefore compositions comprising the same as described herein, may be of particular use in preventing or reducing the growth of bacteria.

[0261] Without wishing to be bound by theory, it is believed that the cycle of bacterial growth is interrupted by the silica particles adsorbing the toxins and / or enzymes released by the bacteria, which toxins and enzymes would therefore no longer be able to damage the host tissue and / or provide the nutrients required for bacterial growth.

[0262] Thus, compositions of the invention may be said to product the effects described herein by inhibition (i.e. by adsorption) of toxins and / or enzymes released by the bacteria.

[0263] As such, compositions of the invention are of particular use in preventing or reducing the growth of bacteria in circumstances where the growth of said bacteria is facilitated by the release of said toxins and / or enzymes, such as where said bacteria area present in combination with a food source, such as biological material (e.g. biological tissue and / or fluids).

[0264] In a particular embodiment, the bacteria are toxin and / or enzyme secreting bacteria.

[0265] In a particular embodiment, the bacteria are enzyme secreting bacteria.

[0266] In particular embodiments, the enzymes secreted are lipases. Thus, in a particular embodiment, the bacteria are enzyme (e.g. lipase) secreting bacteria.

[0267] In a particular embodiment, the bacteria are toxin secreting bacteria.

[0268] In particular embodiments, the toxins secreted are proteins, which may be referred to as bacterial proteins, such as those described in the examples provided herein (e.g. a- toxin). Thus, in a particular embodiment, the bacteria are toxin (e.g. protein) secreting bacteria.

[0269] In a further embodiment, the bacteria are present in combination with a suitable food source (i.e. a source of food for said bacteria, which may be referred to as suitable nutrients).

[0270] Thus, in a further embodiment, the bacteria are toxin and / or enzyme secreting bacteria present in combination with a suitable food source, such as in a nutrient rich media.

[0271] In a particular embodiment, the bacteria (i.e. the bacteria producing the bacterial growth) are bacteria that may infect biological systems, such as living tissue or tissue derived food sources (e.g. biological fluids).

[0272] Thus, in particular embodiments, the bacteria may be referred to as tissue-infecting bacteria.

[0273] For the avoidance of doubt, the term "tissue-infecting bacteria" will include references to bacteria that are able to invade the tissue of a host organism and cause infections. Thus, tissue-infecting bacteria include bacteria which, upon infecting the tissue of the host organism, release proteins or enzymes that are toxic to the host organism (such as a-toxin or lipase). Similarly, the tissue-infecting bacteria, upon infecting the tissue, are capable of releasing toxins or enzymes that are damaging to the tissue. In some embodiments, the tissue-infecting bacteria are necrotising bacteria.

[0274] In some embodiments, the bacteria (e.g. the tissue-infecting bacteria) are selected from the following:

[0275] Staphylococcus aureus

[0276] Streptococcus pyogenes

[0277] Escherichia coli (E. coli)

[0278] Clostridium difficile

[0279] Pseudomonas aeruginosa

[0280] Mycobacterium tuberculosis

[0281] Neisseria gonorrhoeae

[0282] Helicobacter pylori

[0283] Vibrio cholerae

[0284] Chlamydia trachomatis

[0285] Haemophilus influenzae

[0286] Klebsiella pneumoniae

[0287] Enterococcus species

[0288] In some embodiments, the tissue-infecting bacteria are a Staphylococcus, such as Staphylococcus aureus.

[0289] In some embodiments, the tissue-infecting bacteria are a Streptococcus, such as Streptococcus pyogenes.

[0290] In some embodiments, the tissue-infecting bacteria are Escherichia coli (E. coli).

[0291] Products

[0292] For the avoidance of doubt, where the use silica of the invention is in the form of a product or article, such products or articles comprising said silica as defined herein are also within the scope of the invention.

[0293] According to the seventh aspect of the invention, there is provided a porous silica containing product or article as defined herein.

[0294] In a particular embodiment, there is provided a wound healing article comprising porous silica particles as defined in the first aspect of the invention (including all embodiments thereof). In particular embodiments, the wound healing article is selected from the group consisting of a wound dressing, plaster, bandage, gauze pads, gauze rolls, or an absorbent patch or pad.

[0295] In more particular embodiments, the wound dressing is selected from non-adherent dressing, foam dressing, alginate dressing, hydrogel dressing, collagen dressings, sterile wound dressing, hydrocolloid wound dressing, silicone dressing or film dressing.

[0296] In more particular embodiments, the bandage is an adhesive bandage (i.e. bandaid) or a compression bandage.

[0297] According to the eighth aspect of the invention, there is provided the use of a product or article as described in the seventh aspect of the invention or a composition as described in the first aspect of the invention for the purposes as described here.

[0298] In a particular embodiment, there is provided the use of a composition as described in the first aspect of the invention as a wound healing article (such as those described herein).

[0299] Methods of manufacture

[0300] The skilled person will understand that products and articles comprising silica particles as described herein may be prepared using techniques as known to those skilled in the art relating to the manufacture of said product or article.

[0301] For example, products and articles comprising silica particles may be prepared by incorporating the silica particles as described herein during the process of manufacture of that product or article, such as by adding it in place of standard silica (i.e. silica lacking the properties as described herein) or similar materials commonly used in the relevant process of manufacture.

[0302] For example, where the product or article is or comprises a material (such as an absorbent material), the product or article may be prepared by incorporating the silica as described herein in that material, such as by adding it as a component during manufacture. Similarly, where the product or article is a liquid or semi-liquid, the silica material may be added as a component of that liquid or semi-liquid, which may result in the silica being suspended therein.

[0303] Examples

[0304] The present invention will be further described by reference to the following examples, which are not intended to limit the scope of the invention.

[0305] Example 1: Preparation / characterization of porous silica materials

[0306] Materials

[0307] Silica 1 and Silica 3 were manufactured according to a process previously described (see Kupferschmidt, N et al., Nanomedicine. 9:9, 1353-1362 (2014) and Baek, J et al., Nanomedicine. 17: 1, 9-22 (2022), in particular the experimental procedures described therein).

[0308] In brief, Silica 1 was manufactured by dissolving a meso-structure templating agent (P123, a triblock copolymer with average molecular weight = 5800 g mol-1, PEO20PPO70PEO20) in aqueous hydrochloric acid (HCI), with acid concentration equivalent to 1.6 M. Complete dissolution of P123 was followed by addition of tetraethyl orthosilicate (TEOS) under vigorous stirring at 40 °C. The final molar ratio of P123: TEOS in the solution was 0.02: 1.00 and the molar ratio of TEOS: HCI: H2O was 1:7:230. The synthesis was kept static at 40 °C for 20 h and further hydrothermally treated for 10 h at 100 °C. Following hydrothermal treatment, the material was filtered, washed and dried. The material was finally subjected to calcination (550°C in air for 6 h, with 10 h ramp time) to remove the organic template and generate the open porous network.

[0309] The synthesis of Silica 3 was based on the self-assembly of folic acid (FA) pterin groups that forms chiral stacks stabilized by intrinsic n-n interactions. Briefly, these folic acid stacks acted as templates in the synthesis where 3-aminopropyltriethoxysilane (APES) was used as co-structure directing agent and TEOS as silica source. FA was added into distilled water and the solution was kept at 40°C for 2 hours under static condition. The solution was stirred at 500 rpm 40 min before adding the mixture of APES and TEOS. The molar composition of the reaction mixture was FA: APES: TEOS: H2O 1: 2.53: 7.63: 1771. Afterwards, the mixture was stirred for another 2 h at 500 rpm and was subsequently stored at 60°C under static conditions overnight before raising the temperature to 100°C for overnight hydrothermal treatment. The solid product was filtered and dried. The template was removed by calcination at 600°C in air for 12 h.

[0310] Silica 2 was Sunsphere NP-30 obtained from AGC Si-Tech.

[0311] Nitrogen sorption analysis

[0312] Brunauer-Emmett-Teller (BET) surface area was calculated from adsorption isotherm at a relative pressure (p / p°) of <0.2 (plots in Figure 1). Total pore volume were recorded at a relative pressure (p / p°) = 0.995. Average pore size and pore size distributions were derived from the adsorption curves using the Density Functional Theory (DFT) method. The pore size distribution data for the silica particles derived from the adsorption curves using DFT and a cylindrical pores - oxide surface model is presented in Figure 2 (A-C). The measurements were performed at liquid nitrogen temperature (-196 °C) using a TriStar II volumetric adsorption analyser and data analysis was performed using the software MicroActive for TriStar II version 2.03 (Micromeritics Instrument Corp., GA, USA).

[0313] Particle size

[0314] Scanning electron microscopy (SEM) using a JSM-7401F (JEOL Ltd., Tokyo, Japan) was used to characterize the particle size and morphology from SEM micrographs (Figure 3 A-B). The mean particle size (length and width for rod-shaped particles Silica 1 and diameterfor spherical particles Silica 2) were analyzed from >50 particles using Image! (Fiji; see Schindelin J, Arganda-Carreras I, Frise E et al., Fiji: an open-source platform for biological-image analysis., Nat. Methods, 9(7), 676-682 (2012)).

[0315] Table 1: Material characteristics

[0316] Various properties of the studied silica materials were measured using above listed techniques with operational conditions. The features identified are described in Table

[0317] 1 below.

[0318] 1[4 x Total Pore Volume (cm3 / g) / BET Surface Area (m2 / g)] x 1000

[0319] 2Calculated on adsorption curves, using DFT model and assuming a cylindrical pore geometry

[0320] 3Calculated from the DFT pore size distribution and total pore volume: [(Pore Volume at 50 nm - Pore Volume at 2 nm) / Total Pore Volume] x 100

[0321] 4Calculated from the DFT pore size distribution: [(Pore Volume at 25 nm - Pore Volume at 7 nm) / (Pore Volume at 50 nm - Pore Volume at 2 nm)] x 100

[0322] 5Calculated from the DFT pore size distribution: [(Pore Volume at 18 nm - Pore Volume at 7 nm) / (Pore Volume at 50 nm - Pore Volume at 2 nm)] x 100

[0323] Analysis of the properties of these silica materials is also provided in Figures 1, Figure 2 (A-C) and Figure 3 (A-B) as described herein.

[0324] Example 2: Assessment of bacterial in Silica 1 2 and 3.

[0325] Materials

[0326]

[0327] Preparation of stock and working solutions

[0328] Prior to the assay, several stock and working solutions were prepared. lx Running buffer

[0329] 50 mL Bolt MES running buffer 20x was mixed with 950 mL double distilled water (ddH2O). lOx TBS, pH = 7.6

[0330] 80 g NaCI and 24.2 g Trizma base were dissolved in 700 mL ddH2O using a magnetic stirrer. pH was adjusted to 7.6 with IN HCI. ddH2O was added to a final volume of IL. lx TBS

[0331] 100 mL lOx TBS was mixed with 900 mL ddH2O.

[0332] TBST

[0333] 200 mL lOx TBS was mixed with 1780 mL ddH2O and subsequently, 20 mL 10% Tween was added.

[0334] 10% Tween

[0335] 10 mL Tween-20 was mixed with 90 mL ddH2O. lx LDS buffer 1250 pL Bolt™ 4X LDS sample buffer was mixed with 500 pL Bolt™ Sample Reduction Agent (lOx) and 3250 pL ddHzO.

[0336] 2x LDS buffer

[0337] 150 pL Bolt™ 4X LDS sample buffer was mixed with 60 pL Bolt™ Sample Reduction Agent (lOx) and 90 pL ddHzO.

[0338] 2x PBS stock solution, pH = 5.4

[0339] 10 PBS tablets were dissolved in 950 mL ddHzO. Once dissolved, pH was adjusted to

[0340] 5.4 with IN HCI and ddHzO was added up to IL. lx PBS working solution, pH = 5.4

[0341] 50 mL 2x PBS stock solution was mixed with 50 mL ddHzO to obtain a lx PBS working solution.

[0342] Amido Black staining dye

[0343] 2.5 g Amido Black was dissolved in 250 mL methanol and 35 mL acetic acid. ddHzO was added to a final volume of 500 mL.

[0344] Silica stock solutions

[0345] 60-80 mg of mesoporous silica (Silica 1 and Silica 3) or non-porous silica (Silica 2) was weighed and dried overnight at 120 °C. On the next day, silica was weighed again to obtain precise post-dried weight and 20 mg / mL silica suspension was prepared using ddHzO. The silica suspensions were vortexed for homogenous suspension. For Silica 1, sonication was necessary for homogeneous suspension. Briefly, 2 mm microtip was fit into the sonicator and the silica suspension was sonicated for 3 min at 40% amplitude without pulse. After the sonication, silica suspension was mixed several times by inversion and inspected visually. If silica clumps were still present, sonication was repeated once more. Generally, two rounds of sonication resulted in a dispersion with no or minimal clumps remaining.

[0346] S. aureus recombinant proteins stock solutions

[0347] S. aureus recombinant His-tagged alpha-hemolysin (hly, o-toxin) and lipase 1 (lipl) were provided in lyophilized form (1 mg). A 1: 1 mix of ddHzO and 100% glycerol was prepared and 1 mL of it was added to each vial to obtain a recombinant protein stock solution of 1 mg / mL. The stock solution was aliquoted to avoid repeated freeze-thaw cycles and stored at -20 °C. Adsorption of recombinant proteins by silica

[0348] Each silica sample was incubated with each recombinant protein for protein adsorption. The incubation mix was prepared by mixing 450 pL of lx PBS (pH 5.4), 500 pL of silica (1 mg / mL) and 50 pL of the recombinant protein stock solution (1 mg / mL) in 1.5 mL microcentrifuge tube. The incubation solutions were mixed by inversion and incubated for 1 hour at 37 °C with vertical rotation using a rotator. The final concentrations in the incubation mix were: 500 pg / mL silica and 50 pg / mL recombinant protein.

[0349] Sample preparation for gel electrophoresis

[0350] Following the protein adsorption, the incubation mixes were centrifuged at 2000 ref for 5 min at room temperature to separate the adsorbed and non-adsorbed recombinant proteins. Following the centrifugation, the silica and the adsorbed proteins were pulled down in the pellet fraction, while the non-adsorbed proteins remained in the supernatant fraction. 800 pL of the supernatant was transferred to a new 1.5 mL microcentrifuge tube and the rest of the supernatant solution was discarded to obtain a "clean" silica pellet. 65 pL of the supernatant was transferred to a new 1.5 mL tube and mixed with 35 pL 2x LDS buffer. The silica pellet was suspended in 500 pL lx LDS buffer.

[0351] To calculate the relative amount of adsorbed proteins, 2 standard samples of known protein concentrations were prepared (0.5 and 0.25 pg / pL). More specifically, 6 pL lx PBS was mixed with 6 pL of the stock protein solution (1 mg / mL) to obtain a protein solution of 0.5 pg / pL, which was equivalent 3 pg of protein in total. Subsequently, 6 pL of this solution was transferred to a new 1.5 mL tube and mixed with 6 pL lx PBS, which resulted in a 0.25 pg / mL protein solution. 6 pL of this solution was discarded and the total protein amount remaining was 1.5 pg. 4 pL lx PBS and 5.4 pL 2x LDS buffer were added in both standard samples.

[0352] To denature the proteins, all samples were heated at 65°C for 15 minutes in the heat block. After denaturation, the adsorbed proteins were released from the pores of the silica into the solution. Therefore, the silica pellet samples were centrifuged at 2000 ref for 5 min to separate adsorbed proteins in the supernatant fraction from the "empty" silica in the pellet fraction. After centrifugation, supernatant was transferred to a new 1.5 mL tube. This sample was still labelled as "pellet".

[0353] Gel electrophoresis

[0354] Gel electrophoresis was performed according to manufacturer's instruction (Thermo Fisher Scientific). Briefly, the gel was placed in the cassette clamp and in the chamber of the Mini Gel Tank. Once the gel is secured in the tank, pellet / supernatant samples and standard samples were loaded into the gel. The amounts loaded were: 30 pL of the supernatant and pellet samples, 15.4 pL of the standard samples, and 3 pL of each of the molecular weight ladders. The tank was then closed, and the electrodes were connected to the PowerPac 300. The samples were run at 80 V to go through the stacking gel, then at 120 V until the end of the gel.

[0355] Protein transfer to PVDF membrane

[0356] After the gel electrophoresis, the cassette containing the gel was removed from the tank and the two plates were separated. The gel was then placed in a tray containing ddHzO. To assemble the transfer cassette, the bottom stack of a Mini Trans-Blot Turbo transfer pack was placed in the bottom part of the cassette and pressed gently with the western blot roller to remove air bubbles. Subsequently, the gel was placed on top of the bottom stack, pressed with the roller and then the top stack containing a PVDF membrane was placed over the gel. The whole stack was pressed with the roller again and the lid of the cassette was placed on top and locked. The proteins were transferred using the Turbo transfer program for 7 min.

[0357] Protein detection

[0358] After protein transfer, the membrane was either blotted with anti-His antibody or stained with protein detection dyes (Ponceau and Amido Black).

[0359] Anti-His antibody detection

[0360] After the transfer of the proteins, the PVDF membrane was placed in a 50 mL tube with the transferred side facing inwards. 5 mL Intercept® blocking buffer was added and the membrane was incubated for 1 h at room temperature with a low-speed rolling on the tube roller. Following the blocking stage, the blocking buffer was discarded and replaced with the primary antibody solution, which contained 2.5 mL Intercept® blocking buffer, 2.5 mL TBST and 5 pL anti-His antibody. The membrane was incubated overnight at 4°C on the tube roller.

[0361] On the next day, the primary antibody solution was discarded, and the membrane was washed with 20 mL TBST 3 times, 10 min each at room temperature. After the last wash, the secondary antibody solution was added. The secondary antibody solution contained 5 mL Intercept® blocking buffer, 20 mL TBST and 1 pL fluorescently labeled goat anti-rabbit secondary antibody. Once the secondary antibody solution was added the tube was covered with aluminum foil to avoid bleaching of the fluorescence. The membrane was incubated for 1 h at room temperature on the tube roller. After the incubation, the membrane was washed with 20 mL TBST 3 times, 10 min each at room temperature. The membrane was further washed with 20 mL lx TBS 3 times, 10 min each at room temperature.

[0362] An image of the membrane was acquired at a 2 min exposure time using the Odyssey Fc instrument and analyzed with the Empiria Studio® software.

[0363] The amounts of adsorbed a-toxin by Silica 1 and Silica 2 are shown in Figure 4.

[0364] Amido Black staining

[0365] After the transfer of the proteins, the PVDF membrane was placed in a tray containing 20 mL Amido Black and the membrane was stained for 2 min at room temperature with constant shaking. After staining, the dye was discarded and the membrane was washed with ddHzO, until clear protein bands were visible. The membrane was then scanned, and the image was analyzed using the Fiji software.

[0366] The amounts of adsorbed a-toxin by Silica 1 and Silica 3 are shown in Figure 6.

[0367] The amounts of adsorbed lipase by Silica 1 and Silica 2 are shown in Figure 5.

[0368] The amounts of adsorbed lipase by Silica 1 and Silica 3 are shown in Figure 7.

[0369] Image analysis

[0370] The fluorescent image and the images acquired by Amido Black staining were analysed with the Empiria Studio 2.3 and Fiji software, respectively. The intensity of the a-toxin and lipase bands was quantified by the respective software. The amount of adsorbed protein was calculated as a ratio, in which the intensity of the band for each pellet samples was divided by the intensity of the band for the respective supernatant sample

[0371] Example 3: Assessment of f. co / / '-secreted heat-labile enterotoxin (LT toxin) adsorption by Silica 1, 2 and 3.

[0372] Materials Preparation of stock and working solutions

[0373] Prior to the assay, several stock and working solutions were prepared.

[0374] LB medium

[0375] 25 g of LB broth powder was dissolved in 1 L of ddHzO using a magnetic stirrer, then autoclaved (121 °C, 20 min).

[0376] 50% glycerol

[0377] Equal volumes of 100% glycerol and ddHzO were mixed in a glass bottle, then autoclaved (121 °C, 20 min). lx Running buffer

[0378] 50 mL Bolt MES running buffer 20x was mixed with 950 mL ddHzO. lOx TBS, pH = 7.6

[0379] 80 g NaCI and 24.2 g Trizma base were dissolved in 700 mL ddHzO using a magnetic stirrer. pH was adjusted to 7.6 with IN HCI. ddHzO was added to a final volume of IL. lx TBS

[0380] 100 mL lOx TBS was mixed with 900 mL ddHzO.

[0381] TBST

[0382] 200 mL lOx TBS was mixed with 1780 mL ddHzO and subsequently, 20 mL 10% Tween was added.

[0383] 10% Tween

[0384] 10 mL Tween-20 was mixed with 90 mL ddHzO. lx LDS buffer

[0385] 1250 pL Bolt™ 4X LDS sample buffer was mixed with 500 pL Bolt™ Sample Reduction Agent (lOx) and 3250 pL ddHzO.

[0386] 2x LDS buffer

[0387] 150 pL Bolt™ 4X LDS sample buffer was mixed with 60 pL Bolt™ Sample Reduction Agent (lOx) and 90 pL ddHzO. Silica stock and working solutions

[0388] 60-80 mg of mesoporous silica (Silica 1 and Silica 3) or non-porous silica (Silica 2) was weighed and dried overnight at 120 °C. On the next day, silica was weighed again to obtain precise post-dried weight and 20 mg / mL silica suspension was prepared using ddHzO (stock solution). The silica suspensions were vortexed for homogenous suspension. For Silica 1, sonication was necessary for homogeneous suspension. Briefly, 2 mm microtip was fit into the sonicator and the silica suspension was sonicated for 3 min at 40% amplitude without pulse. After the sonication, silica suspension was mixed several times by inversion and inspected visually. If silica clumps were still present, sonication was repeated once more. Generally, two rounds of sonication resulted in a dispersion with no or minimal clumps remaining. To create the silica working solutions, the silica stock solutions were diluted 10 times with ddHzO e.g. 0.1 mL stock silica solution was mixed with 0.9 mL ddHzO.

[0389] Preparation of E. coli glycerol stocks

[0390] Escherichia coli (E. coli) are facultative anaerobic gram-negative bacteria and are part of the normal bacterial flora of the normal gastrointestinal system. Although most E. coli strains are harmless, several serotypes produce toxins that can cause severe foodborne diseases, gastroenteritis, and urinary tract infections, among other health issues. One of the pathogenic serotypes is the enterotoxigenic E. coli (ETEC), a leading bacterial cause of diarrhoea. ETEC produces and secretes toxins, including the heat- labile enterotoxin (LT toxin). The LT toxin consists of two subunits (A and B) and targets the gastrointestinal tract, causing diarrhoea and food poisoning.

[0391] Lyophilized E. coli (American Type Culture Collection (ATCC), 25922) was rehydrated in 5 mL of LB medium. 1 mL of the suspension was aliquoted in five autoclaved flasks and 4 mL of LB medium was subsequently added in all flasks. The inoculated flasks were incubated at 37 °C with constant agitation (shaker set at 120 rpm) overnight. Following incubation, 0.5 mL of each bacterial culture was aliquoted into autoclaved 2 mL cryovials. An equal volume (0.5 mL) of autoclaved 50% glycerol was added to each vial. The contents were mixed by inversion, ensuring any solute on the lid was shaken down. The vials were then stored at -80 °C.

[0392] Preparation of E. coli-secreted proteins

[0393] 20 mL of LB medium was added to a glass flask. A small amount of E. coli glycerol stock was used to inoculate the LB medium. The inoculated culture was incubated overnight (16-24 hr) at 37 °C with constant agitation. After incubation, the entire bacterial culture was poured into 50 mL tubes and centrifuged at 3000 rpm for 10 min at room temperature to pellet the bacterial cells. The supernatant (cell-free LB medium containing E. co / / -secreted proteins) was carefully poured into a new 50 mL tube to avoid pellet disruption.

[0394] Adsorption of E. coli-secreted proteins by silica

[0395] Four 1.5 mL tubes were prepared: one for each silica sample and one for the No-silica control. Into each tube, 0.5 mL of the supernatant of the E. coli bacterial culture was aliquoted. Then, 0.5 mL of the respective silica working solution (2 mg / mL) or ddHzO (for the No-silica control) was added. All tubes were mixed by inversion. For protein adsorption by the silica, the samples were incubated for 1 hr at 37 °C with vertical rotation using a rotator.

[0396] Sample preparation for gel electrophoresis

[0397] Following the protein adsorption, the samples were centrifuged at 2000 ref for 5 min at room temperature to separate the adsorbed and non-adsorbed proteins. Following the centrifugation, the silica and adsorbed proteins were collected in the pellet fraction, while the non-adsorbed proteins remained in the supernatant fraction. 800 pL of the supernatant was collected to a new 1.5 mL tube and the rest of the supernatant solution was discarded to obtain a "clean" silica pellet. 65 pL of the supernatant was transferred to a new 1.5 mL tube and mixed with 35 pL 2x LDS buffer. The silica pellet was suspended in 500 pL lx LDS buffer.

[0398] To denature the proteins, all samples were heated at 65 °C for 15 min in the heat block. After denaturation, the adsorbed proteins were released from the pores of the silica into the solution. Therefore, the silica pellet samples were centrifuged at 2000 ref for 5 min to separate adsorbed proteins in the supernatant fraction from the "empty" silica in the pellet fraction. After centrifugation, supernatant was transferred to a new 1.5 mL tube. This sample was still labelled as "pellet".

[0399] Gel electrophoresis

[0400] Gel electrophoresis was performed as described in Example 2.

[0401] Protein transfer to PVDF membrane

[0402] Protein transfer to PVDF membrane was performed as described in Example 2.

[0403] LT toxin detection

[0404] After the transfer of the proteins, the PVDF membrane was placed in a 50 mL tube with the transferred side facing inwards. 5 mL Intercept® blocking buffer was added and the membrane was incubated for 1 h at room temperature with a low-speed rolling on the tube roller. Following the blocking stage, the blocking buffer was discarded and replaced with the primary antibody solution, which contained 2.5 mL Intercept® blocking buffer, 2.5 mL TBST and 5 pL anti-LT antibody. The membrane was incubated overnight at 4 °C on the tube roller.

[0405] On the next day, the primary antibody solution was discarded, and the membrane was washed with 20 mL TBST 3 times, 10 min each at room temperature. After the last wash, the secondary antibody solution was added. The secondary antibody solution contained 5 mL Intercept® blocking buffer, 20 mL TBST and 1 pL fluorescently labeled goat anti-rabbit secondary antibody. Once the secondary antibody solution was added the tube was covered with aluminum foil to avoid bleaching of the fluorescence. The membrane was incubated for 1 h at room temperature on the tube roller. After the incubation, the membrane was washed with 20 mL TBST 3 times, 10 min each at room temperature. The membrane was further washed with 20 mL lx TBS 3 times, 10 min each at room temperature.

[0406] An image of the membrane was acquired at a 2 min exposure time using the Odyssey Fc instrument.

[0407] A representative image of the membrane is shown in Figure 8.

[0408] Image analysis

[0409] The acquired fluorescent image was analysed with the Image Studio® software. The intensity of each LT toxin subunit band was quantified. The amount of adsorbed protein was calculated as a ratio, where the intensity of each pellet sample band was divided by the intensity of the corresponding supernatant sample band.

[0410] The amounts of LT toxin Subunit A adsorbed by Silica 1, Silica 2, and Silica 3 are shown in Figure 9.

[0411] The amounts of LT toxin Subunit B adsorbed by Silica 1, Silica 2, and Silica 3 are shown in Figure 10. Example 4: Assessment of E. coli colony formation.

[0412] Materials Preparation of stock and working solutions

[0413] Prior to the assay, several stock and working solutions were prepared.

[0414] LB medium

[0415] 25 g of LB broth powder was dissolved in 1 L of ddHzO using a magnetic stirrer, then autoclaved (121 °C, 20 min).

[0416] LB agar plates

[0417] 40 g of LB broth with agar powder was dissolved in 1 L of ddHzO using a magnetic stirrer while heating at approximately 70 °C. The medium was then autoclaved (121 °C, 20 min). Following autoclaving, the medium was poured into 100 mm petri dishes

[0418] (20 mL per dish), covered with lids, and incubated at room temperature overnight to allow the LB agar to solidify. Silica stock solutions

[0419] Silica stock solutions were prepared as described in Example 3.

[0420] Preparation of E. coli glycerol stocks

[0421] E. coli glycerol stocks were prepared as described in Example 3.

[0422] Assessment of E. coli colony formation

[0423] 30 mL of LB medium was added to a glass flask. A small amount of E. coli glycerol stock was used to inoculate the LB medium. The inoculated culture was incubated overnight (16-24 hr) at 37 °C with constant agitation. Following incubation, 9.9 mL of LB medium was added to each of three 15 mL tubes. Then, 100 pL of the bacterial culture was added to the first tube, resulting in a IO-2dilution. The tube was mixed by inversion, and 100 pL was transferred to the second tube, creating 10-4dilution. This tube was mixed by inversion and 100 pL was transferred to the third tube, resulting in a IO-6dilution.

[0424] Next, 1.35 mL of the diluted bacterial culture was added to four wells of a 24-well plate. Then, 150 pL of each of the silica stock solution (20 mg / mL) was added to the respective well. For the No Silica Control, 150 pL ddHzO was added to one well. The plate was sealed with a sealing film and incubated at 37 °C with constant agitation for 3 hours.

[0425] After incubation, 25 pL of each bacterial culture was pipetted onto an agar plate and spread evenly using a glass pipette. All agar plates were incubated inverted at 37 °C overnight. Following this incubation, the number of colonies on each plate was counted. To calculate the colony-forming units per mL (CFU / mL), the number of colonies was divided by the volume of bacterial culture plated (25 pL) and multiplied by the dilution factor (IO-6).

[0426] The number of E. coli colonies formed following the treatment with Silica 1, Silica 2 and Silica 3, expressed as colony forming units per mL (CFU / mL) are shown in Figure 11.

Claims

Claims1. Use of a composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm, in preventing or inhibiting bacterial growth.

2. A method of preventing or inhibiting bacterial growth comprising contacting the bacterial growth medium with a composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm.

3. The use or method of Claim 1 or 2, wherein the bacterial growth is on a surface.

4. The use or method of Claim 3, wherein the surface is solid or semi-solid.

5. The use or method of Claim 4, wherein the surface is an area in human contact, such as furniture (e.g. tabletop, seating, bed) or a handle (e.g. door handle, handrail).

6. The use or method of Claim 4, wherein the surface is material, such as a covering (e.g. clothing, packaging, sanitary products, disposable paper coverings).

7. The use or method of Claim 4 or 6, wherein the surface is a packaging material, such as a food packaging.

8. The use or method of Claim 4, wherein the surface is a medical tool or medical device.

9. The use or method of Claim 3, wherein the surface is living tissue, such as skin or a wound.

10. The use or method of any one of the preceding claims, wherein the bacterial growth is in a semi-solid, liquid, cream, oil, or paste.

11. The use or method of Claim 10, wherein the semi-solid, liquid, cream, oil, or paste is a food item.

12. The use or method of Claim 10, wherein the semi-solid, liquid, cream, oil, or paste is a cosmetic agent or a medicament.

13. A composition comprising porous silica having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25 nm, for use in :(a) the prophylaxis or treatment of a bacterial infection; or(b) inducing and / or accelerating the healing process of a wound.

14. Use of a composition comprising porous silica particles having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25.0 nm, in :(a) the prophylaxis or treatment of a bacterial infection; or(b) inducing and / or accelerating the healing process of a wound.

15. A method for the prophylaxis or treatment of a bacterial infection comprising administering to a patient in need thereof a composition comprising a therapeutically effective amount of porous silica particles having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25.0 nm.

16. A method of inducing and / or accelerating the healing process of a wound by administering to the wound area a composition comprising a therapeutically effective amount of porous silica particles having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25.0 nm.

17. The use, method, or composition for use of any one of the preceding claims, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 22.0 nm.

18. The use, method, or composition for use of any one of the preceding claims, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 20.0 nm.

19. The use, method, or composition for use of any one of the preceding claims, wherein the average pore size of the pores in the mesoporous range is from about 8.0 to about 13.0 nm.

20. The use, method, or composition for use of any one of the preceding claims, wherein at least about 40% by volume of the pores are in the mesoporous range.

21. The use, method, or composition for use of any one of the preceding claims, wherein at least about 21% of the pores in the mesoporous range have a diameter within the range of the average pore size, such as at least about 35% or at least about 50%.

22. The use, method, or composition for use of any one of the preceding claims, wherein the silica particles have a BET surface area of at least about 200 m2 / g.

23. The use, method, or composition for use of any one of the preceding claims, wherein the silica particles have a mean particle size of from about 0.1 to about 20.0 pm.

24. The use, method, or composition for use of any one of the preceding claims, wherein the silica particles have a mean particle size of from about 1.0 to about 5.0 pm.

25. The use, method, or composition for use of any one of the preceding claims, wherein the silica particles have a total pore volume from about 0.7 to about 1.3 cm3 / g.

26. The use, method, or composition for use of any one of Claims 1 to 15 and 17 to 25, wherein the bacteria producing the bacterial growth or the bacterial infection are tissue-infecting bacteria.

27. The use, method, or composition for use of Claim 26, wherein the tissueinfecting bacteria are necrotising bacteria.

28. The use, method, or composition for use of Claim 26, wherein the tissueinfecting bacteria are selected from the group consisting of:Staphylococcus aureus;Streptococcus pyogenes;Escherichia coli (E. coli);Clostridium difficile;Pseudomonas aeruginosa;Mycobacterium tuberculosis;Neisseria gonorrhoeae;Helicobacter pylori;Vibrio cholerae;Chlamydia trachomatis;Haemophilus influenzae;Klebsiella pneumoniae; andEnterococcus species, such as Escherichia coli (E. coli).

29. The use, method, or composition for use of any one of Claims 26 to 28, wherein the tissue is epithelial tissue, such as skin.

30. The use, method, or composition for use of any one of Claims 13 to 15 and 17 to 29, wherein the infection is an infection of a wound.

31. The use, method, or composition for use of any one of Claims 9 to 14 and 16 to 30, wherein the wound is one or more selected from the group consisting of an abrasion, burn, laceration, surgical incision, stab wound, open wound, chronic wound, traumatic wound, diabetic wound, dermatitis and ulcer.

32. The composition for use according to any one of Claims 13 and 17 to 31, wherein the composition is in the form of a solution, cream, gel, an ointment, an emulsion, a suspension, a powder, paste, liquid, gum, serum, a spray (e.g. a film-forming spray) or a dressing (such as a patch or pad).

33. A wound healing article comprising porous silica particles having pores in the mesoporous range, wherein the average pore size of the pores in the mesoporous range is from about 7.0 to about 25.0 nm.

34. The wound healing article of Claim 33, wherein the wound healing article is a wound dressing (such as non-adherent dressing, foam dressing, alginate dressing, hydrogel dressing, collagen dressings, sterile wound dressing, hydrocolloid wound dressing, silicone dressing or film dressing), plaster, bandage (such as adhesive bandage (i.e. bandaid) or compression bandage), gauze pads, gauze rolls, or an absorbent patch or pad.

35. The wound healing article of Claim 33 or 34 having any one of the features of Claims 17 to 32.

36. Use of a composition as defined in any one of Claims 1 to 32 as a wound healing article.

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