Patch for applying to a user's skin

Abstract

A medicant patch 100 for application to a user's skin comprising a formulation compartment 116 containing drug medicants or plasma 118 separated by dividers 115 acting to seperate the formulation into

Description

Common skin issues include skin inflammation (of various types) and skin infections. It is known that plasma can be used to treat various types of skin issues. Skin plasma treatments use cold plasma, where the temperature of the plasma is low enough to be safe for use with the skin. As an example, plasma can be used for wound sterilisation, as plasma treatment can effectively disinfect the skin and activate the skin’s healing. In addition to wound sterilisation, there are a whole host of other benefits which can be achieved by plasma treatment of the skin, such as improved delivery of formulations to the skin, as well as other dermatological benefits. A known mechanism by which to generate plasma is by dielectric barrier discharge (DBD), that is by an electrical discharge occurring between two electrodes which have a dielectric layer between them. In volume dielectric barrier discharge (VDBD), the plasma will be generated in an air gap between the two electrodes. In surface dielectric barrier discharge (SDBD) the plasma will be generated at the surface of the dielectric layer. Plasma treatment devices have been developed which can apply plasma to the skin in order to treat it. Despite this, there is room to improve the existing plasma treatment devices. SUMMARY A first aspect of the disclosure provides a patch for applying to a user’s skin, the patch for use with a plasma generating device, and the patch comprising: a plasma compartment configured to engage with the plasma generating device for generation of plasma within the plasma compartment; a formulation compartment for housing a formulation; and a fluidic channel for fluidly coupling the formulation compartment to the plasma compartment. Due to the presence of the formulation compartment and the fluidic channel for fluidly coupling the formulation compartment to the plasma compartment, a formulation housed within the formulation compartment may be inserted into the plasma compartment after a plasma treatment (in which a plasma generating device may be used to generate plasma within the plasma compartment). For example, the formulation may comprise a formulation (e.g., water or a water-based liquid) for absorbing ozone and / or nitrogen oxides. In this way, the gaseous emissions (e.g., NOx and ozone) produced in the plasma compartment by the plasma may be absorbed by / dissolved in the formulation after the plasma treatment. Thus, the safety of the plasma treatment may be improved. As another example, the formulation may comprise a topical formulation (such as a transdermal / skincare formulation) which may be for cosmetic or medical treatment of the skin. Because the formulation may be applied to the skin immediately following the plasma treatment, when the skin may be more permeable, without removing the patch from the skin, the effectiveness of a skin treatment (e.g., the cosmetic / medical skin treatment) may be improved, while inhibiting the release of gaseous emissions (e.g., NOx and ozone). It will be appreciated that the fluidic channel may extend from the formulation compartment to the plasma compartment. The fluidic channel may be for coupling the formulation compartment to the plasma compartment such as to enable a formulation housed within the formulation compartment, to pass into the plasma compartment. In some examples, the formulation may comprise a solid formulation. In such examples, the fluidic channel may be for coupling the formulation compartment to the plasma compartment such as to enable the solid formulation to pass into the plasma compartment. In some examples, the plasma generating device may comprise a dielectric barrier discharge (DBD) terminal. It will be appreciated that a DBD terminal may refer to one or more electrodes. A DBD terminal may refer to a combination of one or more electrodes and a dielectric layer, where the one or more electrodes may be covered with, or embedded within the dielectric layer. The electrodes may be separated from one another by the dielectric layer. The one or more electrodes may comprise one or more high voltage electrodes (which may be coupled to a high voltage power source) and / or one or more ground electrodes (which may be grounded). For example, the patch may be for use with known plasma generating devices. It will be appreciated that the patch comprising the plasma compartment and / or the formulation compartment may refer to the patch defining the plasma compartment and / or the formulation compartment. In some examples, the patch may comprise: a dielectric cover having an inner surface and an outer surface; a support mechanism for supporting the dielectric cover to define the plasma compartment between the inner surface of the dielectric cover and the user’s skin when the patch is applied to the user’s skin; and wherein the dielectric cover comprises a sealing mechanism for forming an air-tight contact between the outer surface of the dielectric cover and the plasma generating device (e.g., the DBD terminal) for the generation of plasma within the plasma compartment. Due to the sealing mechanism forming an air-tight contact with the plasma generating device (e.g., the DBD terminal), the generation of plasma outside the patch is largely prevented. Thus, the safety of the plasma treatment may be improved. Plasma can be generated within the plasma compartment, and the plasma and gaseous emissions (e.g., nitrogen oxides (NOx) and ozone) and UV which may be produced by the plasma can be held within the plasma compartment. It will be appreciated that an air-tight contact may refer to an air-free contact, for example in which there is no (or negligible) air between the outer surface of the patch’s dielectric cover and the plasma generating device (e.g., the DBD terminal). It will further be appreciated that the plasma compartment may correspond to / may include an air cavity, and that the plasma may be generated within the air cavity. In some examples, the air-tight contact between the outer surface of the dielectric cover of the patch and the plasma generating device (e.g., the DBD terminal) may be such that the outer surface of the dielectric cover covers an entire exposed surface (e.g., which is exposed to the air / to the outside of the plasma generating device) of the DBD terminal. For example, the air-tight contact may be formed between a dielectric layer of the DBD terminal and the outer surface of the patch’s dielectric cover. A plasma treatment according to the present disclosure may comprise, when the plasma generating device (e.g., the DBD terminal) is in air-tight contact with the outer surface of the dielectric cover, applying a high voltage to the DBD terminal (or to at least one of the electrodes within DBD terminal) to generate plasma within the plasma compartment. In some examples, at least a part of the dielectric cover may be formed of an elastic material that can conform to the shape of the plasma generating device (e.g., the DBD terminal) when the plasma generating device (e.g., the DBD terminal) is brought into contact with the outer surface of the dielectric cover. In this way, the air-tight contact between the dielectric cover and the DBD terminal may be improved and / or achieved. Thus, the sealing mechanism may comprise an intrinsic property of the dielectric cover, such as the material from which the dielectric cover is formed. Additionally, or alternatively, the elastic material may mean that the volume of the plasma compartment may be adjustable e.g., by moving the DBD terminal closer to the skin, and / or the distance of the DBD terminal from the skin may be adjustable. As such, there may be an improved control over the plasma treatment. Additionally, or alternatively, the elastic material may mean that use of the patch on different areas of the skin (e.g., on different areas of the face) can be facilitated. In some examples, at least a part of the dielectric cover may be non-elastic or non-stretchable. In some examples, the sealing mechanism may comprise an outer adhesive layer on the outer surface of the dielectric cover. The outer adhesive layer may be capable of adhering the plasma treatment device to the outer surface of the dielectric cover. In this way, the air-tight contact between the dielectric cover and the DBD terminal may be improved and / or achieved. In some examples, the patch may comprise a skin-coupling adhesive. The skin-coupling adhesive may create an air-tight seal between the dielectric cover and the user’s skin when the patch is applied to the user’s skin. The skin-coupling adhesive may be for sealing the plasma compartment from an environment outside of the patch (e.g., by creating an airtight seal between the dielectric cover and the user’s skin when the patch is applied to the user’s skin). The skin-coupling adhesive may be for sealing the plasma compartment such that the only fluid inlet into the plasma compartment is formed by the fluidic channel (e.g., by creating an air-tight seal between the dielectric cover and the user’s skin when the patch is applied to the user’s skin). It will be appreciated that reference to seal(s) / sealing herein may be understood to mean an air-tight seal(s) / sealing. In this way, the plasma and the gaseous emissions (e.g., NOx and ozone) and UV which may be produced by the plasma can be kept within the patch, thus improving the safety of the plasma treatment. The skin-coupling adhesive may also seal the formulation compartment from the environment outside of the patch. For example, the only fluid inlet into the formulation compartment may be formed by the fluidic channel. Therefore, when the plasma compartment is sealed from the environment outside of the patch, the formulation compartment may also be sealed from the environment outside of the patch. It will be appreciated that the environment outside of the patch may refer to the environment external to the plasma compartment and the formulation compartment. The environment outside of the patch may refer to the environment on the outer surface of the dielectric cover. In some examples, the skin-coupling adhesive may be on the inner surface of the dielectric cover. In other examples, the skin-coupling adhesive may be located on another component of the patch (e.g., on a support structure which extends from the inner surface of the dielectric cover, as will be described below). It will be appreciated that the air-tight seal between the dielectric cover and the user’s skin may be direct (e.g., when the skin-coupling adhesive is on the dielectric cover), or indirect (e.g., when the skin-coupling adhesive is on another component of the patch). In some examples, the patch may comprise a compressible cover which extends at least partially over the formulation compartment. For example, the compressible cover may extend over the entire formulation compartment, or the compressible cover may extend over only a portion of the formulation compartment. The compressible cover may extend over 50% or more, or 75% or more of the formulation compartment. The compressible cover may be formed of a manually compressible material, e.g., silicon. The compressible cover may comprise a compressible or elastic material, for example such that a volume of the formulation compartment can be controlled by application of a force to the compressible cover. In this way, the formulation can be pushed out of the formulation compartment and into the plasma compartment by (e.g., manually) compressing the compressible cover. In some examples, the dielectric cover may at least partially define the formulation compartment. The dielectric cover may extend (at least partially) over the formulation compartment. In such examples, the dielectric cover may correspond to the compressible cover. In other examples, the compressible cover may be a separate component to the dielectric cover. In some examples, the formulation compartment and the plasma compartment may be arranged side-by-side (e.g., when the patch is applied to the user’s skin). In other examples, the formulation compartment may extend peripherally (e.g., circumferentially) around the plasma compartment (e.g., when the patch is applied to the user’s skin). The formulation compartment may extend around at least a portion of (e.g., all the way around) the perimeter (e.g., the circumference) of the plasma compartment. The formulation compartment may have an annular cross-section, e.g., as taken perpendicular to a patch axis. The patch axis may be perpendicular to the outer surface and the inner surface of the dielectric cover and / or may extend from the outer surface to the inner surface. The patch axis may be a central axis of the patch. In some examples, the support mechanism may comprise at least a part of the dielectric cover. In some examples, the support mechanism may comprise an intrinsic property of the dielectric cover. For example, the support mechanism may comprise a material of the dielectric cover. For instance, at least a part of the dielectric cover may be formed of a structural (e.g., rigid) material such that the dielectric cover defines a plasma compartment between the inner surface and the user’s skin when the patch is applied to the user’s skin. In some examples, the dielectric cover may be formed of a material sufficiently rigid to define the plasma compartment when the patch is applied to the user’s skin and sufficiently flexible to allow variation of the plasma compartment’s volume. In some examples, the support mechanism may include a support structure extending from the inner surface of the dielectric cover. For example, the support structure may extend from the inner surface of the dielectric cover to the user’s skin when the patch is applied to the user’s skin. In this way, the support structure may enable formation of and / or maintenance of the plasma compartment. In some examples, the support structure may comprise a plasma compartment peripheral frame, e.g., an annular frame, which may extend from the inner surface of the dielectric cover (e.g., to the user’s skin when the patch is applied to the user’s skin). The annular frame may have an annular cross section, e.g., as taken perpendicular to a patch axis. The plasma compartment may be (at least partially) defined by an inner circumferential / perimetral surface of the plasma compartment peripheral frame. The plasma compartment peripheral frame may extend around the perimeter of / circumscribe the plasma compartment. In this way, the dielectric cover may be supported more uniformly, and more uniform plasma generation may be facilitated. In some examples, the plasma compartment peripheral frame may comprise a rigid, or semi-rigid material. For example, the plasma compartment peripheral frame may be formed of a rigid or semi-rigid polymer or plastic. In this way, the support of the dielectric cover may be improved. In some examples, the support structure may comprise a spacer, which may be in the form of a mesh. The spacer may be located within the plasma compartment. The spacer may extend from the inner surface of the dielectric cover (e.g., to the user’s skin when the patch is applied to the user’s skin). The spacer may maintain a uniform gap between the inner surface of the dielectric cover and the user’s skin. The gap may correspond to the plasma compartment. In this way, the gap / plasma compartment may be more uniform across a surface of the skin and / or the plasma may be applied across the skin in a more uniform manner. As mentioned above, in some examples, the skin-coupling-adhesive may be located on the support structure. The support structure may comprise a skin-facing surface which faces towards the skin (when the patch is applied to the user’s skin), and the skin-coupling adhesive may be located on the skin-facing surface of the support structure. For example, the skin-coupling adhesive may be located on a skin-facing surface of the plasma compartment peripheral frame. In this way, the plasma compartment, defined (at least partially by) an inner circumferential / perimetral surface of the plasma compartment peripheral frame, may be sealed from the environment outside of the patch. In some examples, the formulation compartment may be (e.g., at least partially, or fully) defined by the support structure. The formulation compartment may be located within the support structure, e.g., within the plasma compartment peripheral frame. For instance, the formulation compartment may be located between (e.g., sandwiched between) the inner surface of the plasma compartment peripheral frame (which may at least partially define the plasma compartment) and an outer surface of the plasma compartment peripheral frame (which may be opposite to the inner surface). For example, the formulation compartment may be located within the annulus of the annular frame. In this way, the formulation compartment may extend peripherally around the plasma compartment. In some examples, a portion of the support structure (e.g., the plasma compartment peripheral frame) may extend over the formulation compartment. In such examples, the support structure, or the portion of the support structure extending over the formulation compartment, may correspond to the compressible cover. The support structure (e.g., the spacer or the plasma compartment peripheral frame) may comprise a compressible or elastic material, for example such that a volume of the formulation compartment can be controlled by application of a force to the support structure. In some examples, the compressible cover (e.g., the dielectric cover) may be (e.g., directly) coupled / sealed to the support structure e.g., the plasma compartment peripheral frame. In such examples, the formulation compartment may be defined by the support structure and the compressible cover. In some examples, the patch may comprise a formulation compartment peripheral frame, which may at least partially define the formulation compartment. The formulation compartment peripheral frame may extend around / circumscribe the formulation compartment. The formulation compartment peripheral frame may have an annular cross section, e.g., as taken perpendicular to a patch axis. The formulation compartment may be (at least partially) defined by the formulation compartment peripheral frame, e.g., by an inner circumferential / perimetral surface of the formulation compartment peripheral frame. In some examples, the compressible cover may be (e.g., directly) coupled / sealed to the formulation compartment peripheral frame. In some examples, the patch may comprise a formulation compartment base surface, which may at least partially define the formulation compartment. The formulation compartment base surface may be opposite to the compressible cover. The formulation compartment base surface may be coupled / sealed to the formulation compartment peripheral frame. The formulation compartment may be defined between the compressible cover and the formulation compartment base surface. The formulation compartment base surface may be positioned to contact the skin when the patch is applied to the skin. In this way, the formulation may be housed within the formulation compartment when the patch is applied to the skin. In some examples, the patch may comprise a framework, the framework comprising: the plasma compartment peripheral frame, the formulation compartment peripheral frame, and / or the formulation compartment base surface. The plasma compartment peripheral frame and the formulation compartment peripheral frame may be arranged side-by-side. The framework may comprise a connector defining the fluidic channel therein, the connector (e.g., directly) coupling the formulation compartment peripheral frame to the plasma compartment peripheral frame. In this way, the formulation compartment and the plasma compartment may be arranged side-by-side (e.g., when the patch is applied to the user’s skin). In some examples, the formulation compartment peripheral frame may be integrally formed with the plasma compartment peripheral frame. In some examples, the formulation compartment peripheral frame and the plasma compartment peripheral frame may be moulded as a single part. In this way, manufacture of the patch may be facilitated. Additionally, or alternatively, the patch may be more robust. Also, support of the dielectric cover and / or the compressible cover may be provided. In other examples, the formulation compartment and the plasma compartment may be formed as multiple concentric parts joined together. As an example, the framework may have a cross-section, e.g., as taken perpendicular to the patch axis, which is (approximately) the shape of the number eight. In some examples, the patch may comprise one or more layers. The patch may comprise a first layer (or an upper layer), a second layer (or a middle layer) and a third layer (or a base layer). For example, the framework may be formed of one or more layers (e.g., the first layer, the second layer and the third layer). The layers may be stacked on top of one another. The second layer may be arranged between the first layer and the third layer. In some examples, the second layer may comprise / define the fluidic channel. The second layer may be formed of an adhesive material (e.g., double sided tape) to couple the first layer and the second layer together. The second layer may comprise a first adhesive side adhered to the first layer and a second adhesive side, opposite the first adhesive side, adhered to the third layer. In some examples, the flexibility of the second layer may be higher than the flexibility of the first layer and / or than a flexibility of the third layer. One or more of the layers (e.g., the first layer and / or the third layer) may be formed of plastic such as semi-rigid plastic. One or more of the layers (e.g., the first layer and the second layer) may be formed of two annuluses (e.g., a larger annulus and a smaller annulus), which may be joined by a connector strip. One or more of the layers (e.g., the third layer) may be formed of an annulus (e.g., a larger annuus) and a circle (e.g., a smaller circle), which may be joined by a connector strip. One or more of the layers may have a cross-section, e.g., as taken perpendicular to the patch axis, which is (approximately) the shape of the number eight. Together, two or more of the layers may form the formulation compartment peripheral frame and / or the plasma compartment peripheral frame. For example, the (e.g., larger) annulus(es) of one or more of the layers (e.g., the first layer, the second layer and the third layer) may form the plasma compartment peripheral frame and the (e.g., smaller) annulus(es) of one or more of the layers (e.g., the first layer and the second layer) may form the formulation compartment peripheral frame. One or more of the layers (e.g., the third layer) may form the formulation compartment base surface. For example, the (e.g., smaller) circle of the third layer may form the formulation compartment base surface. Together, two or more of the layers (e.g., the first layer, the second layer and the third layer) may form the connector. For example, the connector strips (of e.g., the first layer, the second layer and the third layer) may form the connector. The fluidic channel may be defined by the connector strip of the second layer. In some examples, the patch may be formed of a single layer. The patch may be formed of a single material, or the patch may be formed of multiple materials. In some examples, the fluidic channel may be longer than the shortest distance between the plasma compartment and the formulation compartment. For example, the fluidic channel may extend along (at least a portion of) the periphery of the formulation compartment and / or the plasma compartment. It will be appreciated that the fluidic channel may be partially defined by the formulation compartment peripheral frame and / or the plasma compartment peripheral frame. In this way, formulation from the formulation compartment may be inhibited from entering the plasma compartment, e.g., during the plasma treatment, before the compressible cover is compressed. If a formulation were present in the plasma compartment during the plasma treatment, the formulation may be modified by the plasma. Additionally, or alternatively, in the presence of a formulation, plasma generation may be less effective and / or less well controlled, and the effectiveness of plasma treatment in increasing the permeability of the skin may be significantly reduced. In some examples, the patch comprises a barrier, which may be located in the fluidic channel. The barrier may be configured to prevent fluid (or the formulation) moving from the formulation compartment to the plasma compartment. The patch may have a first configuration in which the barrier prevents fluid (or the formulation) moving from the formulation compartment to the plasma compartment, and a second configuration in which the barrier allows fluid (or the formulation) to move from the formulation compartment to the plasma compartment. For example, the barrier may be removeable or breakable (e.g., upon compression of the compressible cover). The barrier may be formed of a (e.g., thin layer of) polymer or plastic, such as polydimethylsiloxane (PDMS), polyethylene (PE), or polypropylene (PP) cellophane films. In some examples, the thickness of the barrier may be at least 10 microns and no more than 2000 microns. In this way, formulation from the formulation compartment may be inhibited from entering the plasma compartment, e.g., during the plasma treatment, before the compressible cover is compressed. In some examples, the barrier may be configured to form an air-tight seal between the formulation compartment and the plasma compartment. For example, in the first configuration, the formulation compartment may be sealed. In this way, the formulation may be inhibited from breaking down or degrading before use. In some examples, the patch (e.g., the formulation compartment) may comprise / define a connecting element configured to connect to a formulation reservoir (that may be external to the patch) to allow flow of formulation from the formulation reservoir into the formulation compartment, and / or to a gas supply reservoir (that may be external to the patch) to allow flow of gas from the gas supply reservoir into the formulation compartment, which may assist the flow of the formulation from the formulation compartment into the plasma compartment. The connecting element may define an inlet into the formulation compartment. For example, when the formulation compartment is (at least partially) defined by the support structure, the support structure may form the connecting element and / or define the inlet. The inlet may face away from the plasma compartment. The formulation reservoir may include a connection tube insertable into the inlet for the flow of formulation into the formulation compartment. Instead of an inlet, the connecting element of the formulation compartment may alternatively be in the form of an adaptor protruding from the formulation compartment and engageable with the connection tube of the formulation reservoir. In this way, the formulation may be inserted into the formulation compartment after manufacture of the patch. The inlet into the formulation compartment and the outlet of the fluidic channel (e.g. microfluidic channel), through which the formulation enters the plasma compartment, may be located at different positions (e.g., different circumferential positions) around the patch axis, and / or may have different angular co-ordinates with respect to the patch axis. The difference between the angular co-ordinates may be at least 90 degrees, and / or no more than 270 degrees. For example, the difference between the angular co-ordinates may be approximately 180 degrees. In this way, the plasma compartment may be better separated from the environment outside of the patch. In some examples, the formulation compartment may contain at least one formulation. In some examples, the formulation compartment may contain two or more formulations, each formulation being separated from the other formulations by one or more dividers. For example, the one or more dividers may comprise one or more liquid / water barriers (which may be non-reacting / inert with respect to the formulations which they separate), and / or one or more air / gas barriers (which may be non-reacting / inert with respect to the formulations which they separate). For example, the one or more dividers may comprise a silicon-based liquid / gel barrier (e.g., cyclopentasiloxane or dimethicone), low viscosity PDMS (polydimethylsiloxane) barrier, a light oil-based barrier (e.g., squalane or caprylic / capric triglyceride), or a biocompatible solvent (e.g., propylene glycol or glycerin) barrier. The one or more dividers may comprise a nitrogen (N2) barrier or an argon (Ar) barrier. In this way, the formulations may be inhibited from reacting with one another before use by a barrier which may be non-reacting / inert and / or have low solubility with respect to the formulations which they separate. The one or more dividers may comprise one or more dividers which are breakable or removeable (e.g., upon compression of the compressible cover). The one or more dividers may comprise a divider (e.g., a breakable / removeable divider) which has a first configuration (e.g., an unbroken configuration) in which the divider separates two formulations, and a second configuration (e.g., a broken configuration) in which the divider allows the two formulations to come into contact with one another. The breakable divider may be formed of a (e.g., thin layer of) polymer or plastic, such as polydimethylsiloxane (PDMS), polyethylene (PE), or polypropylene (PP) cellophane films. In some examples, the thickness of the breakable divider may be at least 10 microns and no more than 2000 microns. In this way, the formulations may be inhibited from reacting with one another before use by a divider which may be non-reacting / inert with respect to the formulations which they separate, and which may break / rupture upon application of pressure to the divider. In some examples, the at least one (or the two or more) formulation(s) may comprise at least one solid formulation, at least one liquid formulation and / or at least one gel formulation. In some examples, the fluidic channel may enable the mixing of the two or more formulations (e.g., a solid formulation and a liquid formulation) before the formulations pass into the plasma compartment. In some examples, the at least one (or the two or more) formulation(s) may comprise at least one formulation / liquid for absorbing or dissolving ozone and / or nitrogen oxides, e.g., water or a water-based liquid. In this way, the gaseous emissions (e.g., NOx and ozone) produced by the plasma may be absorbed by / dissolved in the formulation after the plasma treatment. Thus, the safety of the plasma treatment may be improved. In some examples, the at least one (or the two or more) formulation(s) may comprise at least one topical formulation (such as a transdermal / skincare formulation) which may be for cosmetic or medical treatment of the skin. The at least one topical / transdermal / skincare formulation may be for treating pigmentation, fine lines, dark spots, acne, and / or inflammation of the skin. Because the formulation may be applied to the skin immediately following the plasma treatment, when the skin may be more permeable, without removing the patch from the skin, the effectiveness of a skin treatment (e.g., the cosmetic / medical skin treatment) may be improved, while inhibiting the release of gaseous emissions (e.g., NOx and ozone). In some examples, the at least one (or the two or more) formulation(s) may comprise at least one solid formulation, e.g., ascorbic acid (vitamin C), retinol (vitamin A), hydroquinone, niacinamide (vitamin B3), or an enzyme (e.g., papain, or bromelain). In some examples, the at least one (or the two or more) formulation(s) may comprise at least one liquid formulation e.g., an oil-based or water-based liquid formulation such as hyaluronic acid, niacinamide (vitamin B3), panthenol (vitamin B5), aloe vera extract, green tea extract, caffeine, salicylic acid, alpha-hydroxy acids (AHAS) like glycolic acid and lactic acid, beta-glucan, peptides, vitamin E (tocopherol), retinol (vitamin A), coenzyme Q10 (ubiquinone), ceramides, fat-soluble vitamins (like vitamin K), chia seed oil, or tetrahexyldecyl ascorbate. In some examples, the support structure (e.g., the spacer) may be dissolvable by the formulation. The support structure may be formed / made of a material which dissolves to a liquid when the formulation (e.g., the liquid formulation) is inserted into the plasma compartment. The support structure may be formed / made of a dehydrated gel / liquid formulation. The support structure may be formed / made of a freeze fried material or a polymer material. In this way, the support structure may become part of the formulation. In some examples, the dielectric cover may have a thickness of no more than 2000 microns, for example no more than 200 microns. It will be appreciated that a thickness may refer to a size along a direction parallel to the patch axis. In this way, the dielectric cover may have limited impact on the plasma generation. In some examples, the dielectric cover may have a thickness of at least 20 microns. In this way, ease of manufacture and / or use of the patch (e.g., attaching the patch to the user’s skin) may be improved. In some examples, the thickness of the support structure may be at least 0.1 mm, for example at least 0.5 mm, and / or no more than 10 mm, for example no more than 8 mm, or no more than 1.5 mm. In some examples, the thickness of the skin-coupling adhesive may be no more than 1000 microns, for example no more than 50 microns or no more than 5 microns, and / or at least 5 microns. Thus, in some examples, a total thickness of the patch may be at least 0.5 mm and / or no more than 10 mm, for example no more than 2 mm. In some examples, a diameter or diagonal width of the patch, or of the dielectric cover, may be at least 5 mm and / or no more than 200 mm, for example no more than 10 mm or no more than 5 mm. The diameter or diagonal width of the patch (or dielectric cover) may be understood to mean the diameter or diagonal width of the cross-section of the patch (or dielectric cover) perpendicular to the path axis. In this way, a cross-sectional area of the patch or dielectric cover (e.g., taken perpendicular to the patch axis) may be larger than (e.g., at least double the size of) the cross-sectional area of a patch-facing surface of the plasma generating device (e.g., which includes the DBD terminal). As such, coupling of the device to the patch may be facilitated. In some examples, the diameter of the fluidic channel may be at least 10 microns and / or no more than 1000 microns. The length of the fluidic channel may be at least 10 mm and / or no more than 100 mm. The fluidic channel may be referred to as a microfluidic channel. In some examples, the volume of the formulation compartment may be smaller than the volume of the plasma compartment. The volume of the plasma compartment may be at least 50 mm3 and / or no more than 1000 mm3. The volume of the formulation compartment may be at least 300 mm3 and / or no more than 1500 mm3. In some examples, the dielectric cover may be formed of a polymer film. In some examples, the dielectric cover may be formed of polyurethane (PU), such as a polyurethane film, polypropylene, such as a polypropylene film, or thermoplastic polyreuthane (TPU), such as a thermoplastic polyreuthane film. In this way, the patch may be stretchable and / or flexible, which may facilitate application of the patch to the user’s skin. In some examples, the patch may be stored or packaged in an inert gas (e.g., a dried inert gas) or in a vacuum. In this way, the degradation of the patch materials, and / or the formulation may be inhibited. A second aspect of the present disclosure provides a plasma generating device for use with a patch according to the first aspect of the invention. The plasma-generating device may be engageable with the dielectric cover and / or with the plasma compartment of the patch for generation of plasma within the plasma compartment. The plasma generating device may include a high voltage power supply, a dielectric barrier discharge terminal comprising an electrode electrically coupled to the high voltage power supply and a controller operable to control the high voltage power supply. In some examples, the plasma generating device may include a formulation reservoir for housing a formulation. The plasma generating device may further include a connection tube extending from (and fluidly coupled to) the formulation reservoir. The connection tube may be for inserting the formulation from the formulation reservoir into the formulation compartment of the patch (e.g., via the connecting element of the patch). In some examples, the plasma generating device may include a gas (e.g., air) supply reservoir for housing a gas (e.g., air). The plasma generating device may further include a connection tube extending from (and fluidly coupled to) the gas supply reservoir. The connection tube may be for inserting gas from the reservoir into the formulation compartment of the patch (e.g., via the connecting element of the patch), which may assist the flow of formulation from the formulation compartment into the plasma compartment. In some examples, the plasma generating device may include a user interface operable to cause formulation within the formulation reservoir to exit the formulation reservoir, e.g., through the connection tube. For example, the user interface may comprise a button (e.g., a compressible button), which may be operable to push the formulation out of the reservoir (e.g., by increasing the pressure within the reservoir). The button may be formed of silicon. In this way, the formulation may be inserted into the formulation compartment after manufacture of the patch. A third aspect of the present invention provides a system for administering plasma to a user’s skin, the system comprising the patch according to the first aspect, and a plasma generating device. The plasma generating device may be engageable with the dielectric cover and / or with the plasma compartment of the patch for generation of plasma within the plasma compartment. The plasma generating device may be a plasma generating device according to the second aspect. It will be appreciated that any of the features, or any combination of the features described with reference to the first aspect, or the second aspect of the disclosure are equally applicable to the third aspect. A fourth aspect of the present invention provides a patch for applying to a user’s skin, the patch comprising a formulation compartment comprising at least one divider partitioning the formulation compartment into a plurality of spaces, wherein each space is configured to house a formulation and a compressible element configured to be compressed to remove the at least one divider to allow mixture of the formulations housed by the respective spaces. In this way, different formulations may be stored separately in the patch, which can help prolong the shelf-lives of the formulations. Occasionally, the composition to be applied to the user’s skin may include a mixture of mutually reactive formulations or formulations in different forms (e.g., solid, liquid (e.g. oil) forms). Pre-mixing these formulations to form the composition for storage on a patch may affect the efficacy or stability of the composition over time. On the other hand, if the different formulations are stored in different storage containers, it may be troublesome for the user. By storing the different formulations on a single patch in the respective spaces of the formulation compartment, the formulations may be separated prior to use and the user convenience may be improved. In some examples, the at least one divider may be breakable upon compression of the compressible element. The at least one divider may have a first configuration (e.g. an unbroken configuration) in which the at least one divider separates two formulations, and a second configuration (e.g. a broken configuration) in which the at least one divider allows the two formulations to come into contact with one another. For example, the at least one divider may comprise a polymer or plastic (e.g. a thin layer of polymer or plastic). For example, the at least one divider may be formed of one or more of the following: polydimethylsiloxane (PDMS), polyethylene (PE), polypropylene (PP) cellophane films. In some examples, the thickness of the at least one breakable divider may be at least 10 microns and no more than 2000 microns. The at least one breakable divider may be formed together with the frames of the patch (either as separate parts or integrally formed), and the formulations may then be inserted into the spaces partitioned by the dividers. This may provide a straightforward way of inserting the formulations. In some examples, the formulation compartment may comprise the formulations. The formulations may comprise at least one solid formulation, at least one liquid formulation and / or at least one gel formulation. In some examples, the formulations may comprise at least one formulation / liquid for absorbing or dissolving ozone and / or nitrogen oxides, e.g., water or a water-based liquid. In some examples, the formulations may comprise at least one topical formulation (such as a transdermal / skincare formulation). For example, the formulations housed by different spaces may comprise different skincare formulations. These formulations may be for cosmetic or medical treatment of the skin, for example, for treating pigmentation, fine lines, dark spots, acne, and / or inflammation of the skin. The at least one divider may comprise a liquid / water or a gas / air. The liquid / water or gas / air may be non-reacting / inert with respect to the formulations which they separate. For example, the at least one divider may comprise one or more of the following: a silicon-based liquid or gel (e.g., cyclopentasiloxane or dimethicone), low viscosity polydimethylsiloxane, oil-based liquid (e.g. squalane or caprylic / capric triglyceride), a biocompatible solvent (e.g., propylene glycol or glycerin), nitrogen, argon. In this way, the formulations may be inhibited from reacting with one another before use by a barrier which may be non-reacting / inert and / or have low solubility with respect to the formulations which they separate. In some examples, the patch may comprise a further compartment and a fluidic channel for fluidly coupling the formulation compartment to the further compartment; where the formulations housed by the different spaces are inserted into the further compartment upon compression of the compressible element. In this way, the further compartment may first be used for a particular function (e.g. for increasing the permeability of the skin via plasma generation or via application of a primer etc.) and the formulations in the formulation compartment may be inserted into the further compartment thereafter. The fluidic channel may enable the mixing of the formulations (e.g. a solid formulation and a liquid formulation) before the formulations pass into the further compartment. In some examples, the patch may comprise a barrier within the fluidic channel, where the barrier may be configured to prevent fluid (or the formulations) from moving from the formulation compartment to the further compartment. The patch may have a first configuration in which the barrier prevents fluid (or the formulations) moving from the formulation compartment to the plasma compartment, and a second configuration in which the barrier allows fluid (or the formulations) to move from the formulation compartment to the plasma compartment. For example, the barrier may be configured to be removable upon compression of the compressible element. The barrier may be formed of a (e.g., thin layer of) polymer or plastic, such as polydimethylsiloxane (PDMS), polyethylene (PE), or polypropylene (PP) cellophane films. In some examples, the thickness of the barrier may be at least 10 microns and no more than 2000 microns. In this way, formulations from the formulation compartment may be inhibited from entering the further compartment before the compressible element is compressed. In some examples, the barrier may be configured to form an air-tight seal between the formulation compartment and the further compartment. For example, in the first configuration, the formulation compartment may be sealed. In this way, the formulation may be inhibited from breaking down or degrading before use. In some examples, the formulation compartment and the further compartment are arranged side-by-side (e.g., when the patch is applied to the user’s skin). In other examples, the formulation compartment may extend peripherally (e.g. circumferentially) around the further compartment (e.g., when the patch is applied to the user’s skin). The formulation compartment may extend around at least a portion of (e.g., all the way around) the perimeter (e.g., the circumference) of the further compartment. The formulation compartment may have an annular cross-section, e.g., as taken perpendicular to a patch axis. The patch axis may be perpendicular to the outer surface and the inner surface of a cover of the further compartment and / or may extend from the outer surface to the inner surface. The patch axis may be a central axis of the patch. In some examples, the fluidic channel may be longer than the shortest distance between the further compartment and the formulation compartment. For example, the fluidic channel may extend along (at least a portion of) the periphery of the formulation compartment and / or the further compartment. It will be appreciated that the fluidic channel may be partially defined by the formulation compartment peripheral frame and / or the further compartment peripheral frame. In this way, formulation from the formulation compartment may be inhibited from entering the further compartment before the compressible element is compressed. This allows the contents in the further compartment to perform their function more effectively. In some examples, a volume of the formulation compartment may be smaller than a volume of the further compartment. For example, the volume of the further compartment may be at least 50mm3 and / or no more than 1000mm3. The volume of the formulation compartment may be at least 300mm3 and / or no more than 1500mm3. In some examples, the compressible element may comprise a compressible cover which extends at least partially over the formulation compartment. For example, the compressible cover may extend over the entire formulation compartment, or the compressible cover may extend over only a portion of the formulation compartment. The compressible cover may extend over 50% or more, or 75% or more of the formulation compartment. The compressible cover may be formed of a manually compressible material, e.g., silicon. The compressible cover may comprise a compressible or elastic material, for example such that a volume of the formulation compartment can be controlled by application of a force to the compressible cover. In this way, the formulation can be pushed out of the formulation compartment and in some examples, into the further compartment by (e.g., manually) compressing the compressible cover. In some examples, the patch may comprise a further cover over the further compartment and the further cover may at least partially define the formulation compartment. The further cover may extend (at least partially) over the formulation compartment. In such examples, the further cover may correspond to the compressible cover. In other examples, the compressible cover may be a separate component to the further cover. In some examples, the compressible element may be formed of a polymer film. The compressible element may be formed of polyurethane (PU), such as polyurethane film, polypropylene, such as a polypropylene film, or thermoplastic polyreuthane (TPU), such as a thermoplastic polyreuthane film. In this way, the patch may be stretchable and / or flexible, which may facilitate application of the patch to the user’s skin. In some examples, the patch may comprise a support structure having a compressible (or elastic) part, where the formulation compartment may be located within the support structure and the compressible element may comprise the compressible part of the support structure. The compressible part of the support structure may extend over the formulation compartment. The volume of the formulation compartment may be controlled by application of a force to the support structure. In this way, the compressible element may be integrally formed with the support structure holding the formulations, thus simplifying the manufacturing process. In some examples, the patch (e.g. the formulation compartment) may comprise / define a connecting element configured to connect to a formulation reservoir (that may be external to the patch) to allow flow of formulation from the formulation reservoir into the formulation compartment. The connecting element may alternatively or also be configured to connect to a gas supply reservoir (that may be external to the patch) to allow flow of gas from the gas supply reservoir into the formulation compartment, which may assist the flow of the formulations from the formulation compartment into the further compartment. The connecting element may define an inlet into the formulation compartment. For example, when the formulation compartment is (at least partially) defined by the support structure, the support structure may form the connecting element and / or define the inlet. In some examples, the further compartment may comprise a plasma compartment configured to engage with a plasma generating device for generation of plasma within the plasma compartment. Due to the presence of the formulation compartment and the fluidic channel for fluidly coupling the formulation compartment to the plasma compartment, the formulations housed within the formulation compartment may be inserted into the plasma compartment after a plasma treatment (in which a plasma generating device may be used to generate plasma within the plasma compartment). These formulations may be useful for absorbing ozone and / or nitrogen oxides produced during the plasma treatment or may be topical formulations (such as transdermal / skincare formulations) for cosmetic or medical treatment of the skin. In some examples, the patch may be a cosmetic patch. For example, the formulations housed by the different spaces may include different skincare formulations. It will be appreciated that for each of the aspects of the disclosure, the examples provided may be combined in any suitable combination to provide further examples, except where such a combination is clearly impermissible or expressly avoided. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a cross-sectional side view of a patch according to the present disclosure. Fig. 2A shows a top view of the components of a patch according to the present disclosure. Fig. 2B shows a top view of the components of a patch according to the present disclosure. Fig. 3A shows a cross-sectional side view of a patch according to the present disclosure. Fig. 3B shows a cross-sectional top view of a patch according to the present disclosure. Fig. 4A shows a cross-sectional side view of a system for administering plasma to a user’s skin. Fig. 4B shows a cross-sectional side view of a system for administering plasma to a user’s skin. DETAILED DESCRIPTION Fig. 1 shows a cross-sectional side view of a patch 100 according to the present disclosure, where the patch 100 is applied to a user’s skin 102. The patch 100 comprises: a framework which includes support structures in the form of a plasma compartment peripheral frame 104 and a formulation compartment peripheral frame 106 coupled to one another by a connector 108, a dielectric cover 110 (formed of an elastic material) sealed to the plasma compartment peripheral frame 104, and a compressible cover 112 (in the form of a silicon button) sealed to the formulation compartment peripheral frame 106. The plasma compartment peripheral frame 104 and the formulation compartment peripheral frame 106 each has an annular cross section taken perpendicular to the patch axis (which extends perpendicularly from the outer surface of the patch to the inner surface of the patch). When the patch 100 is applied to the user’s skin 102, a plasma compartment 114 is defined between the inner surface of the dielectric cover 110 and the skin 102, with the plasma compartment peripheral frame 104 circumscribing the plasma compartment 114. The plasma compartment 114 contains a spacer 115 in the form of a mesh which extends from the inner surface of the dielectric cover 110 to the user’s skin 102. It will be understood that the plasma compartment peripheral frame 104 and the spacer 115 together form a support structure which supports the dielectric cover 110 to define the plasma compartment 114. Although not shown in Fig. 1, the patch 100 further includes a skin-coupling adhesive located on the skin-coupling surface of the plasma compartment peripheral frame 104. The skin-coupling adhesive creates an air-tight seal with the user’s skin 102 to seal the plasma compartment 114 from the environment outside of the patch 100. In addition to the plasma compartment 114, a formulation compartment 116 (which is shown housing a formulation 118 in Fig. 1) is defined between the compressible cover 112 and a formulation compartment base surface 120 sealed to the formulation compartment peripheral frame 106, with the formulation compartment peripheral frame 106 circumscribing the formulation compartment 116. As shown in Fig. 1, the formulation compartment 116 and the plasma compartment 114 are arranged side-by-side. The connector 108 defines a channel which may be a microfluidic channel 122 and which extends from the formulation compartment 116 to the plasma compartment 114 to fluidly couple the formulation compartment 116 to the plasma compartment 114 and enable the formulation 118 from the formulation compartment 116 to be inserted into the plasma compartment 114. To begin the plasma treatment, a DBD terminal of a plasma generating device (not shown in Fig. 1) is brought into contact with the outer surface of the dielectric cover 110. To ensure that an air-tight contact is achieved between the DBD terminal and the dielectric cover 110, the dielectric cover 110 includes a sealing mechanism. In the example shown in Figure 1, the sealing mechanism is achieved by virtue of the elastic material of the dielectric cover 110. The elastic material means that the dielectric cover 110 conforms to the shape of the DBD terminal. In other examples, the sealing mechanism may additionally / altematively comprise an outer adhesive layer on the outer surface of the dielectric cover 110. When the DBD terminal is in airtight contact with the outer surface of the dielectric cover 110, a high voltage can be applied to the DBD terminal. Plasma is then generated within the plasma compartment 114. Due to the airtight contact between the dielectric cover 110 and the DBD terminal, plasma is prevented from being generated outside of the patch 100. In the example shown in Figure 1, the thickness of the dielectric cover 110 is no more than 200 microns, and thus the dielectric cover 110 has limited impact on the plasma generation. After the plasma has been generated in the plasma compartment 114, the formulation 118 in the formulation compartment 116 can be inserted into the plasma compartment 114. In particular, the formulation 118 can be pushed out of the formulation compartment 116 and into the plasma compartment 114 by manually compressing the compressible cover 112. In some examples, the formulation 118 is a liquid such as water, in which ozone and / or nitrogen oxides within the plasma compartment 114 can be dissolved. In this way, the gaseous emissions produced by the plasma may be dissolved in the formulation 118 after the plasma treatment. Thus, the safety of the plasma treatment may be improved. In some examples, the formulation 118 may comprise a transdermal / skincare formulation e.g., for cosmetic or medical treatment of the skin 102. Such a formulation 118 may be a solid, a liquid, or a gel for example. Because the formulation 118 is applied to the skin 102 immediately following the plasma treatment (when the skin 102 is more permeable) without removing the patch 100 from the skin 102, the effectiveness of the formulation 118 in treating the skin 102 (e.g., cosmetically or medically) can be improved, while inhibiting the release of the gaseous emissions produced by the plasma. Fig. 2A shows a top view of the components of the patch 100, and Fig. 2B shows an exploded top view of the patch 100 which demonstrates how the components of the patch 100 are arranged. Figs. 2A and 2B show that the framework of the patch 100 is formed of three layers stacked on top of one another: a base layer 124, a middle layer 126 and an upper layer 128. The upper layer 128 and the middle layer 126 are each formed of two annuluses (a larger annulus 126a / 128a and a smaller annulus 126b / 128b) joined by a connector strip 126c / 128c. The base layer 124 is formed of an annulus (a larger annulus 124a) and a circle (a smaller circle) 120 joined by a connector strip 124c. Together, the larger annuluses 124a / 126a / 128a of the three layers form the plasma compartment peripheral frame 104, while the smaller annuluses 126b / 128b of the middle layer 126 and the upper layer 128 together form the formulation compartment peripheral frame 106, and the smaller circle 120 of the base layer 124 forms the formulation compartment base surface 120. The connector strips 124c / 126c / 128c of each of the layers together form the connector 108, with the connector strip 126c of the middle layer 126 defining the channel (e.g. the microfluidic channel) 122 therein. The upper layer 128 and the base layer 124 are each formed of semi-rigid plastic, and the middle layer 126 is formed of an adhesive material (specifically, double-sided tape) to couple and seal the layers together. In other words, the middle layer 126 includes a first adhesive side for adhering to the upper layer 128 and a second, opposite adhesive side for adhering to the base layer 124. As shown in Fig. 2A, the channel 122 is longer than the shortest distance between the plasma compartment 114 and the formulation compartment 116, with the fluidic channel (which may take the form of a microfluidic channel) 122 extending along a portion of the periphery of the formulation compartment 116 and a portion of the periphery of the plasma compartment 114. That is to say, rather than taking a direct shortest route from the plasma compartment 114 to the formulation compartment 116, the channel 122 is positioned at an angle to the shortest path between the two compartments 114, 116, thereby maximising the length of the channel 122. This may inhibit the formulation 118 from entering the plasma compartment 114 during the plasma treatment before the compressible cover 112 is compressed. Although not shown in the figures, in some examples, the patch 100 may additionally, or alternatively comprise a barrier in the fluidic channel 122. The barrier may be configured to prevent the formulation 118 moving from the formulation compartment 116 to the plasma compartment 114, and may be breakable upon compression of the compressible cover 112, such as to allow the formulation 118 to move from the formulation compartment 116 to the plasma compartment 114. This may also inhibit the formulation 118 from entering the plasma compartment 114 during the plasma treatment before the compressible cover 112 is compressed. Figs. 2A and 2B further demonstrate that the compressible cover 112 is sealed to the smaller annulus 128b of the upper layer 128 with the formulation housed in the formulation compartment 116, and that the dielectric cover 110 is sealed to the larger annulus 128a of the upper layer 128 with the spacer 115 located within the plasma compartment 114. Fig. 3A shows a cross-sectional side view of another patch 200 according to the present disclosure, where the patch 200 is applied to the user’s skin 102. The patch 200 shown in Fig. 3A shares several features in common with that described with reference to Figs. 1, 2A and 2B. For conciseness, discussion of these features may not be repeated here. As shown in Fig. 3A, the patch 200 comprises a dielectric cover 210 and a plasma compartment peripheral frame 204, which has an annular cross section, and which extends from the dielectric cover 210 to the user’s skin 102. In this example, the plasma compartment peripheral frame 204 is formed of a compressible material. When the patch 200 is applied to the user’s skin 102, a plasma compartment 214 is defined between the inner surface of the dielectric cover 210 and the skin 102, with the plasma compartment peripheral frame 204 circumscribing the plasma compartment 214. The plasma compartment 214 contains a spacer 215 in the form of a mesh which extends from the inner surface of the dielectric cover 210 to the user’s skin 102. In addition to the plasma compartment 214, a formulation compartment 216 is defined by the plasma compartment peripheral frame 204. Specifically, the formulation compartment 216 is located within the annulus of the plasma compartment peripheral frame 204. Thus, the formulation compartment 216 extends circumferentially around the plasma compartment 214. The plasma compartment peripheral frame 204 further defines a microfluidic channel 222 which extends from the formulation compartment 216 to the plasma compartment 214 to fluidly couple the formulation compartment 216 to the plasma compartment 214 and enable the formulation 118 from the formulation compartment 216 to be inserted into the plasma compartment 214. In addition, the plasma compartment peripheral frame 204 defines an inlet 230 for inserting the formulation 118 into the formulation compartment 216 (e.g., from an external reservoir). The difference between the angular co-ordinate of the inlet 230 (with respect to the patch axis) and that of the outlet of the fluidic channel (which may be a microfluidic channel) 222 is approximately 180 degrees (in the plane transverse to the patch axis). In this way, the plasma compartment 214 may be better separated from the environment outside of the patch 200. Although not shown in Fig. 3A, the patch 200 further includes a skin-coupling adhesive located on the skin-coupling surface of the plasma compartment peripheral frame 204. The skin-coupling adhesive creates an air-tight seal with the user’s skin 102 to seal the plasma compartment 214 such that the only fluid inlet into the plasma compartment 214 is formed by the channel (which may be a microfluidic channel) 222. Fig. 3B shows a cross-sectional top view of the patch 200 shown in Fig. 3A. As shown in Fig. 3B, the patch 200 includes four different formulations 118a / b / c / d. For example, each of the formulations 118a / b / c / d may be a different transdermal / skincare formulation for cosmetic / medical treatment of the skin 102. The formulation compartment 216 contains dividers 232a / b / c / d to separate the formulations 118 from one another. In particular, the dividers 232a / b / c / d partitions the formulation compartment 216 into a plurality of spaces, where each space houses a formulation 118a / b / c / d. In the example shown in Fig. 3B, the dividers 232a / b / c / d are inert liquid barriers or inert gas barriers (which are non-reacting with respect to the formulations 118a / b / c / d). After the plasma has been generated in the plasma compartment 214, the formulations 118a / b / c / d in the formulation compartment 216 can be inserted into the plasma compartment 214 by manually pressing the portion of the (compressible) peripheral frame which extends over the formulation compartment 216. The formulations 118a / b / c / d and the dividers 232a / b / c / d will each be pushed out of the formulation compartment 216 into the plasma compartment 214. In the plasma compartment 214, the dividers 232a / b / c / d no longer separate the formulations 118a / b / c / d, allowing the formulations 118a / b / c / d to be mixed in the plasma compartment 214. In other examples, the dividers may be breakable dividers which each have an unbroken configuration in which the divider separates the formulations 118a / b / c / d from one another, and a broken configuration in which the divider allows the formulations 118a / b / c / d to come into contact with one another. For example, the breakable dividers may each be formed of a thin layer of plastic. In one example, the formulation compartment 216 comprising the different formulations 118a / b / c / d is filled by inserting each formulation 118a / b / c / d, followed by each liquid / gas divider 232a / b / c / d sequentially into the formulation compartment 216 through the inlet 230. In another example, the plasma compartment peripheral frame 204 includes a bottom part and a top part. The top part is removable from the bottom part to allow filling of the formulation compartment 216. In this example, the dividers may be breakable dividers that are connected with (either as separate parts or integrally formed with) the bottom part of the frame 204. Fig. 4A shows a system 240 for administering plasma to a user’s skin 102. The system 240 includes a plasma generating device 242 and the patch 200 described with reference to Figs. 3A and 3B. The plasma generating device 242 includes a high voltage power supply 244, and a dielectric barrier discharge (DBD) terminal formed of a single electrode 248 covered by a dielectric layer 250, with the electrode 248 being electrically coupled to the high voltage power supply 244. Although not shown in Figure 1, the plasma generating device 242 further comprises a controller operable to control the high voltage power supply 244. Fig. 4A also shows a filling device 252 which includes a reservoir 254 for housing a formulation 118 and a connection tube 256 extending from the reservoir 254 for inserting the formulation 118 from the reservoir 254 into the formulation compartment 216 of the patch 200 via the inlet 230. Fig. 4B shows another system 260 for administering plasma to a user’s skin 102. The system 260 of Fig. 4B shares several features in common with that of Fig. 4A as indicated by like reference numerals. The plasma generating device 262 shown in Fig. 4B includes a formulation reservoir 264 for housing a formulation 118, and a connection tube 266 extending from the reservoir 264 for inserting the formulation 118 from the reservoir 264 into the formulation compartment 216 of the patch 200 via the inlet 230. The plasma generating device 262 includes a compressible silicon button 268 operable to push the formulation 118 out of the reservoir 264, and through the connection tube 266, by increasing the pressure within the reservoir 264. Whilst particular examples and embodiments have thus far been described, it should be understood that there are illustrative only and that various modifications may be made without departing from the scope of the invention as defined by the claims. For example, the formulation compartment 116 of the patch 100 may also include different formulations separated from one another by one or more dividers. Similarly, the formulation compartment 216 of the patch 200 may include any number of formulations. For instance, it may not include dividers and may instead have only a single formulation. Alternatively, it may include more than four formulations. In addition, the spacer 215 of the patch 200 may be optional. Furthermore, the formulation compartment 116 of the patch 100 may also include an inlet similar to the inlet 230 of the patch 200 for inserting formulation from a formulation reservoir (e.g. formulation reservoir 254 or 264) into the formulation compartment 116. In addition, it would be appreciated that the patches 100, 200 may be used for other purposes. For example, they may be general cosmetic patches including, but not limited to, anti-wrinkle patches, hydration patches and brightening patches. Instead of a plasma compartment, the patches 100, 200 can include a further compartment for a different purpose (e.g. it may contain a primer to be applied to the skin prior to applying the formulation(s) in the formulation component). Alternatively, the further compartment may be omitted. In these patches, the formulation compartment 116, 216 can include either one formulation or multiple formulations. These multiple formulations may be in different forms (e.g. solid, oil or liquid forms) and / or may be mutually reactive.

Claims

1. A patch for applying to a user’s skin, the patch comprising:a formulation compartment comprising at least one divider partitioning the formulation compartment into a plurality of spaces, wherein each space is configured to house a formulation; anda compressible element configured to be compressed to remove the at least one divider to allow mixture of the formulations housed by the respective spaces.

2. A patch according to claim 1, wherein the at least one divider is breakable upon compression of the compressible element.

3. A patch according to any preceding claim, wherein the at least one divider comprises a polymer or plastic.

4. A patch according to any preceding claim, wherein the at least one divider is formed of one or more of the following: polydimethylsiloxane, polyethylene, polypropylene cellophane films.

5. A patch according to claim 1, wherein the formulation compartment comprises the formulations.

6. A patch according to claim 5, wherein the at least one divider comprises a liquid or a gas.

7. A patch according to claim 6, wherein the at least one divider comprises one or more of the following: a silicon-based liquid or gel, low viscosity polydimethylsiloxane, oil-based liquid, a biocompatible solvent, nitrogen, argon.

8. A patch according to any preceding claim, further comprising:a further compartment; anda fluidic channel for fluidly coupling the formulation compartment to the further compartment;wherein the formulations housed by the different spaces are inserted into the further compartment upon compression of the compressible element.

9. A patch according to claim 8, further comprising a barrier within the fluidic channel, wherein the barrier is configured to prevent fluid from moving from the formulation compartment to the further compartment.

10. A patch according to claim 9, wherein the barrier is configured to be removable upon compression of the compressible element.

11. A patch according to any one of claims 8 to 10, wherein the formulation compartment and the further compartment are arranged side-by-side when the patch is applied to the user’s skin.

12. A patch according to any one of claims 8 to 10, wherein the formulation compartment extends peripherally around the further compartment.

13. A patch according to any one of claims 8 to 12, wherein the fluidic channel is longer than the shortest distance between the further compartment and the formulation compartment.

14. A patch according to any one of claims 8 to 13, wherein a volume of the formulation compartment is smaller than a volume of the further compartment.

15. A patch according to any preceding claim, wherein the compressible element comprises a compressible cover which extends at least partially over the formulation compartment.

16. A patch according to any one of claims 1 to 15, further comprising a support structure having a compressible part, wherein the formulation compartment is locatedwithin the support structure and the compressible element comprises the compressible part of the support structure.

17. A patch according to any preceding claim, wherein the formulation compartment 5 comprises a connecting element configured to connect to a formulation reservoir to allow flow of formulation from the formulation reservoir into the formulation compartment.

18. A patch according to any one of claims 8 to 16, wherein the further compartment comprises a plasma compartment configured to engage with a plasma generating device for 10 generation of plasma within the plasma compartment.

19. A patch according to any one of claims 5 to 17, wherein the formulations housed by different spaces comprise different skincare formulations.

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