A particle

Abstract

A particle for a tattoo ink comprises a mineral material, and a pigment, where the pigment is dispersed in the mineral material. Preferably, the mineral material comprises a porous ceramic, such as lithium disilicate, or calcium hydroxyapatite, which forms a matrix structure, for the pigment. Preferably, the particle does not comprise a polymer. The pigment may be selected from the group consisting of metal oxides, or carbon black. A tattoo ink may comprise such particles, water, and an additive such as an antifoaming agent. A method of synthesising the particle may comprise precipitating the mineral in the presence of the pigment. A method of tattooing using the tattoo ink; and also a method of removing a tattoo comprising the particles by using artificial light, are also disclosed.

Description

FIELD The present description relates to relates to mineral material particles for tattoo ink. BACKGROUND The practice of permanently marking skin has been around for thousands of years. One issue with tattooing is the permanence of the ink. There is a need to be able to remove tattoos, refine tattoos by partial removal, and add detail to tattoos by partial removal. It is known to remove permanent tattoos by irradiation with a laser, this is termed ‘laser removal’. An issue with laser removal of conventional tattoo ink is multiple laser sessions are required to progressively fade and eventually remove the tattoo. Further issues with laser removal include the high cost, especially over multiple sessions, and the pain and discomfort associated with the removal process. There is a long felt need for tattoo ink that can be removed more easily and less painfully. Known tattoo inks are manufactured from materials that are intended to be permanent, in other words remain in the dermis. There is a need to provide a tattoo ink that does not degrade over time in the body and yet is easily removed by laser irradiation. Conventional black tattoos are known to fade to appear bluish, green or brown over time. Colour tattoos are also known to fade, particularly red ink is known to deteriorate. Sunlight is known to cause degradation of the appearance of tattoos. There is a need for a tattoo ink that does not fade in sunlight. Intricate designs may include portions of the skin which do not have tattoo ink. These can be difficult to produce as the tattoo ink may become blown out into the surrounding skin which makes intricate, fine line detail in the absence of colour difficult to achieve. There is a need to be able to have fine line detail within a tattoo design which does not comprise colour. The present invention seeks to alleviate one or more of the problems detailed herein. SUMMARY OF THE INVENTION In a first aspect there is provided a particle for a tattoo ink comprising: a mineral material; and a pigment; wherein the pigment is dispersed in the mineral material. In a second aspect there is provided a tattoo ink composition comprising: the particles in accordance with the first aspect; water; and an additive selected from a group consisting of: an antifoaming agent, a dispersant, a surfactant, a humectant, a rheological additive, a pharmacologically active agent, or a combination of two or more thereof. In a third aspect there is provided a method of producing a particle for a tattoo ink comprising: synthesising a mineral material in the presence of a pigment; wherein in the particle the pigment is dispersed in the mineral material. In a fourth aspect there is provided a particle for a tattoo ink, wherein the particle is produced according to the third aspect. In a fifth aspect there is provided use of a particle in accordance with the first or fourth aspect in a tattoo ink. In a sixth aspect there is provided a method of tattooing, comprising applying the tattoo ink in accordance with the second aspect to a human or animal. In a seventh aspect there is provided a method of removing a tattoo comprising: irradiating a tattoo comprising particles in accordance with the first or fourth aspect with an artificial light source. DESCRIPTION OF THE DRAWINGS The present invention will now be described by way of example with reference to the accompanying drawings. In the drawings: Figure 1 shows a schematic cross section of a particle. Figure 2 shows a schematic cross section of a particle having pores. Figure 3 shows a schematic sectional view of a particle having a homogeneous distribution of pores. Figure 4a shows a schematic of a tattoo design as applied and after refinement with a laser. Figure 4b shows a schematic of detail in a tattoo design. DETAILED DESCRIPTION The following description is presented to enable any person skilled in the art to make and use the invention and is provided in the context of a particular application. Various modifications to the disclosed embodiments will be apparent to those skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the present invention. Embodiments are described by way of example only. There is provided a particle for a tattoo ink comprising: a mineral material; and a pigment; wherein the pigment is dispersed in the mineral material. The particle is advantageous for a tattoo ink as the pigment is located and retained in the particle such that the pigment is visible. The pigment being dispersed in the mineral material means that the particles can be used in a tattoo ink and the particles applied as a tattoo is not substantially broken down by the body which means the colour of the tattoo may be maintained. Without being bound by theory, it is thought that the pigment which is dispersed in the mineral material is substantially held in position in the mineral material and does not migrate within the skin. This helps maintain the precision as well as the colour of a tattoo. Further, it is an advantage of the invention that the tattoo can be removed far more easily than standard tattoos, for example by reducing the number of laser sessions required to remove the colour from the tattoo. When a laser is applies, it is thought that the pigment that is dispersed in the mineral material is urged to migrate out of the particle, where it can then be dispersed. The mineral material therefore has a dual function of protecting the pigment from the body when the tattoo is desired and allowing the pigment to be released when there is a desire to remove the tattoo. A further advantage is that a laser can be used to apply fine detail to a tattoo. This allows pigment to be carefully and precisely removed from a tattoo due to the ease of removal of the pigment from the tattoo. This means that the absence of pigment in a tattoo can be applied with greater precision. There is not a need to leave areas without pigment which would often cause the pigment to have a ‘blown out’ appearance, seen as a migration of the ink beyond the area to which it was applied. Additionally, if there are gaps in the tattoo and the pigment migrates into these, these can be corrected using a laser due to the ease of removal of the pigment. Further, corrections or amendments to the tattoo can also be made due to the ease of removal of the pigment. It is an advantage of the particle that the colour and position of the pigment can be carefully controlled in the tattoo, while still allowing removal of the pigment for design detail, correction, amendments or changes of mind about a tattoo. Figure 1 shows a schematic cross section of a particle. The particle 100 comprises a mineral material 101, shown in figure 1 as grains of mineral material, and pigment 102. The pigment 102 is dispersed throughout the particle. In the example of figure 1, interstices 103 are shown between the mineral material 101 and the pigment 102 is located in the interstices 103. It will be appreciated that each interstice may have no pigment, or one or more particles of pigment present. The mineral material preferably comprises calcium, phosphorus, silicon, or a combination of two or more thereof. The mineral material comprising calcium, phosphorus or silicon is advantageous because such minerals have desired properties such as being biocompatible and being substantially insoluble in water. Preferably, biocompatible means that an item, such as the particle described herein, will not cause substantial tissue irritation and / or will not be carcinogenic. Preferably, insoluble means a solubility of less than 0.1 g / dL in water at 25 °C, preferably less than 0.01 g / dL in water at 25 °C. The particle is preferably biocompatible. The mineral material preferably comprises a biomaterial. A biomaterial may be defined as a synthetic or natural substance suitable for direct interaction with components of a living system. Preferably the particle is sterile. The mineral material preferably comprises a synthetic biomaterial. This is particularly advantageous as the mineral material can be synthesised in the presence of the pigment to form the particle. Preferably, the particle is not substantially broken down when in the body. It will be appreciated that the particle preferably advantageously can be removed by a laser. Some examples of biomaterials are naturally occurring in the human body, other example of biomaterials are synthetic and bio-mimetic. Bone is a biomaterial and significant constituents of human bone are calcium and phosphorus. A minor constituent of human bone is silicon, for example in collagen. Preferably the mineral material is a hydroxyapatite. A hydroxyapatite is a biocompatible material which can be synthesised in the presence of a pigment. Further, a hydroxyapatite is substantially insoluble in water. Preferably the mineral material is substantially crystalline, preferably substantially polycrystalline. The mineral material being crystalline advantageously provides the particle with desirable physical properties such as mechanical properties. Preferably the mineral material comprises a plurality of interstices, preferably each particle contains at least about two interstices, preferably about 2 to about 2000 interstices, preferably about 10 to about 1000 interstices, preferably about 20 to about 500 interstices. The pigment is preferably located in the interstices of the mineral material. The pigment being located in the interstices of a mineral material particle means that the colour and intensity of tattoos made with ink containing such particles does not substantially deteriorate over time. Preferably at least about 5% of the interstices comprise pigment, preferably about 5% to about 100%, preferably about 10% to about 90%, preferably about 20% to about 80%, preferably about 30% to about 70%. It is an advantage of the invention that the intensity of the colour of the ink can be controlled by controlling the amount of pigment present in each particle. The interstices are preferably distributed throughout the mineral material, preferably the interstices are substantially homogenous throughout the mineral material. This gives the mineral material a substantially uniform structure. Preferably, the interstices are pores. Preferably, the mineral material is porous. A porous structure facilitates the migration of the pigment out of the mineral material when a laser is applied. Preferably, the interstices have an average diameter in the range of about 1 nm to about 500 nm, preferably about 10 nm to about 100 nm. Such sizes are suitable for containing the pigment. Preferably the pigment is distributed throughout the particle, preferably the pigment is distributed substantially homogeneously throughout the particle. This allows an even distribution of colour throughout the particle and helps ensure the uniformity of the tattoo ink. Figure 2 shows a schematic of a particle 200 having interstices 203. The pigment 102 is located within the interstices 203. The interstices 203 may be pores. The mineral material preferably forms a matrix structure. Preferably the pigment is located in the matrix structure. Preferably the pigment is located in interstices of the mineral matrix. Preferably, for a mineral material having a plurality of interstices, the plurality of interstices of the mineral material form a matrix structure. The plurality of interstices may preferably form a tortuous structure. Figure 3 shows a schematic representation of an example of the distribution of interstices in a particle 300. A mineral material 101 has a substantially homogenous distribution of interstices 203. Preferably, the mineral material is coloured, preferably the mineral material is black, white, red, yellow, green, blue, orange, brown, pink, purple, ora combination of two or more thereof. The mineral material may be naturally coloured, or may be dyed. An advantage of a coloured mineral material is that the intensity of the colour of the particle is enhanced by having a coloured mineral material and a pigment. Surprisingly, the tattoo can still be easily removed by the application of the laser. Sufficient energy can be provided to remove just the pigment by breaking down the pigment. Sufficient energy can be provided to break down the pigment and the mineral. The breaking down of the pigment by laser excitation may cause the mineral to break down. The pigment is preferably a particulate pigment. This is a suitable form for dispersing the pigment within the mineral material. The pigment is preferably distributed throughout the particle. Preferably the pigment is distributed substantially homogeneously throughout the particle. Preferably the pigment is distributed substantially homogeneously in the interstices of the mineral material. Preferably the pigment is distributed substantially homogeneously in the interstices of the mineral material. Particles having pigment throughout the particle, particularly a homogeneous distribution of pigment have a more predictable and even pigment colour intensity. Put another way, various particles having a substantially homogeneously distribution of pigment throughout will have a sim ilar intensity of colour that is independent of particle size. Preferably an external surface of the particle comprises pigment. Without being bound by theory, it is speculated that pigment is adsorbed or bonded to surface atoms of the mineral. This adds to the intensity of the colour of the ink. The mineral material preferably comprises a metal oxide, an alkali metal salt, an alkaline earth metal salt, or a combination of two or more thereof. The mineral material preferably comprises an anionic fragment containing at least one of phosphorus, carbonate, sulfur, carbon, silicon, aluminium, or boron, and a cationic fragment containing at least one alkali metal element or alkaline earth metal element. The mineral preferably comprises a salt. These materials have particular utility as a mineral material. These materials have a particular utility as a biocompatible material. The mineral material preferably comprises a ceramic. Preferably the mineral material comprises a biocompatible ceramic. Preferably the mineral material comprises metal oxides of aluminium, zirconium, silicon, or a combination of two or more thereof. Preferably the metal oxides are modified by boron oxide, phosphorus oxide, fluorine, sodium oxide, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide, or a combination of two or more thereof. These materials have particular utility as a mineral material. These materials have a particular utility as a biocompatible material. The mineral material preferably comprises lithium disilicate, calcium carbonate, an aluminium oxide, a zeolite, calcium glycerophosphate or a combination of two or more thereof. Preferably the mineral material comprises a calcium hydroxyapatite, a phosphorous hydroxyapatite, a magnesium hydroxyapatite, or a combination of two or more thereof. Such materials allow a pigment to be dispersed within them, for example, they may comprise interstices of an appropriate size to contain a pigment, particularly a particulate pigment. The hydroxyapatite structure is particularly advantageous as it comprises interstices within its crystal structure, and / or between crystals that can contain the pigment. A hydroxyapatite is particularly advantageous because it is biocompatible. The particle preferably has a solubility of less than 0.1 g / dL in water at 25 °C, preferably a solubility of less than 0.01 g / dL in water at 25 °C. The mineral material preferably has a solubility of less than 0.1 g / dL in water at 25 °C, preferably a solubility of less than 0.01 g / dL in water at 25 °C. The mineral material preferably has a solubility of less than 0.1 g / dL in blood at 37 °C. Advantageously, this means the particle is not substantially soluble in blood or in the dermis. Preferably the particle does not comprise a polymer. It is an advantage that it is not necessary to include a polymer in the particle. It is believed that a polymer could compete with the pigment for space in the interstices and thus reduce the intensity of the colour of the pigment. Further, it is believed that the presence of a polymer may reduce or prevent the expulsion of pigment from a mineral material by laser irradiation. Further, polymers can break down inside the body to carcinogenic compounds meaning that they pose a risk to health. Preferably the particle does not have a core-shell structure. A core-shell structure may reduce or prevent the expulsion of pigment from a mineral material by laser irradiation. Visibility may be defined in terms of optical absorbance and / or optical transmission. The mineral material preferably has a higher optical transmittance than the pigment. Optical transmission can be measured using a photodetector. Percent transmission (%T) is the used to quantitatively express how a sample transmits light. Percent transmission is measured at a particular wavelength (or wavelength range) and is the ratio of transmitted light intensity (I) to incident light intensity (Io), expressed as a percentage: I %T = — x 100 'o The mineral material preferably has an optical transmittance of more than about 50%, preferably the optical transmittance of the mineral material is more than about 70%, preferably the optical transmittance of the mineral material is more than about 90%. This allows the pigment to be seen through the mineral material, and thus allows the colour of the pigment to be the desired vibrancy. It is an advantage that the mineral material comprises dispersed pigment that is visible when viewing the particles. Preferably the pigment is substantially optically opaque. This is an advantage as the pigment can be clearly seen when it is dispersed in the particle. The particle preferably has a D90 particle size between about 500 nm and about 500 pm, preferably the particle has a D90 particle size between about 1 pm and about 100 pm, preferably the particle has a D90 particle size between about 10 pm and about 50 pm. The particle size can be measured by X-ray diffraction, laser diffraction, dynamic light scattering, or sieving, preferably by laser diffraction. The particle size is advantageous for use in a tattoo ink, the particles are sufficiently small so as to be able to penetrate the skin by puncturing and to not be rejected by the body and sufficiently large to appear as coloured in the skin and not be broken down by bodily processes such as by macrophages. Preferably the mineral material has a substantially cubic microstructure or a substantially hexagonal microstructure. The mineral material preferably has a microstructure that accommodates pigment in interstices of the mineral material. The pigment preferably has a D90 particle size between about 5 nm and about 100 nm, preferably between about 10 nm and about 60 nm, preferably about 20 nm. The pigment is preferably selected from the group consisting of metal oxides, zinc, molybdenum, carbon, carbon black, organic colourants or a combination of two or more thereof. Such pigments are suitable for dispersing in the mineral material. Preferably the pigment comprises carbon black. Preferably the mineral material comprises a hydroxyapatite and the pigment comprises carbon black. This combination allows substantially black tattoos to be applied while still facilitating easier tattoo removal. The particle may preferably be produced by comminution of a body comprising the mineral material and the pigment. For example, a comminution process may be performed on a body of mineral material that is about 0.5 cm3 to about 3 cm3 to produce particles smaller than the body. This allows the production of larger mineral material and pigment bodies that can then be comminuted to the desired size. This allows for an efficient process. Preferably the ratio of pigment to mineral material is about 0.1:99.9 to about 20:80 by weight. Preferably the ratio of pigment to mineral material is about 1:99 to about 15:85 by weight. It is an advantage of the invention that a smaller amount of pigment is required than mineral material as this facilitates the removal of the pigment from the tattoo, when this is required. There is provided a tattoo ink composition comprising the particles as described above. The tattoo ink preferably comprises water. The tattoo ink preferably further comprises an additive selected from a group consisting of an antifoaming agent, a dispersant, a surfactant, a humectant, a rheological additive, a pharmacologically active agent, or a combination of two or more thereof. Such additives improve the performance of the tattoo ink. The tattoo ink containing a pharmacologically active agent may preferably be used to administer the pharmacologically active agent as a medicament. There is provided a tattoo ink composition comprising the particles as described above, preferably comprising water, preferably further comprising an additive selected from a group consisting of an antifoaming agent, a dispersant, a surfactant, a humectant, a rheological additive, or a combination of two or more thereof. Preferably the tattoo ink is sterile. This is advantageous for a human or animal body to not reject the tattoo ink if applied and to not cause a significant immune response. The antifoaming agent is preferably an alcohol. Preferably the alcohol is ethanol. The antifoaming agent may preferably be propylene glycol or methanol. The humectant is preferably one or more selected from the group consisting of glycerol, hyaluronic acid, alpha-hydroxy acids, propylene glycol, panthenol, urea, and pyrrolidone carboxylic acids. The tattoo ink composition may preferably comprise a surfactant. The function of a surfactant in the composition is to reduce the surface tension of the ink and improve flowability. The tattoo ink preferably comprises about 30 wt% to about 60 wt% water, preferably about 35 wt% to about 50 wt% water. This allows the particles to be easily tattooed on to the skin. The tattoo ink preferably comprises about 20 wt% to about 40 wt% of the particles. This is a useful level of particle loading to introduce into the skin. This is a suitable percentage for the ink to flow and have adequate vibrancy. The tattoo ink preferably comprises about 5 wt% to about 30 wt% of the additive, preferably about 10 wt% to about 25 wt%. There is provided a method of producing a particle for a tattoo ink comprising synthesising a mineral material in the presence of a pigment, wherein in the particle the pigment is dispersed in the mineral material. Preferably the synthesised mineral material comprises a plurality of interstices, and preferably the pigment is located in the plurality of interstices. Preferably in the method, synthesising the mineral material comprises precipitating the mineral material in the presence of the pigment, preferably a particulate pigment. The method may preferably comprise comminution of a body comprising the mineral material with the dispersed pigment. This allows particles of the required size to be made. An illustrative example of a method of synthesis is provided. A hydrothermal synthesis of lithium disilicate is provided in which 1 g of carbon black, 3 g of Li2CO3 and 9 g of SiO2.H2O are added to 1000 mL of hot aqueous 0.3 M NaOH under magnetic stirring at 80°C. The pH in the resulting solution is adjusted, with stirring, with a 1M NaOH solution, to a pH value = 7 + 0.5. The solution is stirred for around 30 minutes. The solution is heated at 100°C for about an hour. The solution is cooled to room temperature and filtered. The filtrate is washed in water several times. The product is filtered again and allowed to dry. The particle size may be adjusted as necessary by grinding and sieving the dry product. Particles comprising a lithium disilicate mineral material with a carbon black pigment dispersed in the lithium disilicate can therefore be formed. A further illustrative example of a method of synthesis is provided. A synthesis of calcium hydroxyapatite containing carbon black is provided in which 1 g of carbon black, 30 g of Ca(NO3)2(H2O)4 and 15 g of H3PO4 solution are added to 1000 mL of water. The pH in the resulting solution is adjusted, with stirring, with a 1M NaOH solution, to a pH value = 7 + 0.5. The solution is stirred for around 30 minutes. The resulting solution is kept at room temperature for around 24 hours. The solution is filtered using a vacuum pump. The filtrate is washed in water then dried at 50°C. The particle size may be adjusted as necessary by grinding and sieving the dry product. Particles comprising a calcium hydroxyapatite mineral material with a carbon black pigment dispersed in the calcium hydroxyapatite can therefore be formed. There is provided a particle for a tattoo ink, wherein the particle is produced according to the method described herein. The particle for a tattoo ink is preferably used in a tattoo ink. There is provided a method of tattooing, comprising applying the tattoo ink to a human or animal. Preferably the tattoo ink is applied using a tattooing needle. There is provided a method of removing a tattoo comprising irradiating a tattoo comprising particles as described above with an artificial light source. The artificial light source is preferably a laser. Preferably the laser has a wavelength of 1064 nm. The laser preferably has a spot diameter of about 2 mm to about 10 mm, preferably about 6 to 10 mm, a frequency of about 1-10 Hz, and a power of about 200 MJ to about 800 M, preferably about 400 MJ to about 600 MJ, preferably about 500 MJ. The method of removing a tattoo may preferably comprise irradiation by two or more lasers, the lasers having a combined power of about 200 MJ to about 800 MJ, preferably about 500 MJ. Figure 4a shows a representation of an applied tattoo. As seen on the right at 401, the lines of the tattoo are not straight. At 401, there are various features that may be seen as errors, for example the apex of the star points is not a sharp, acute angle; there is an overlap of lines at one of the star points. A refined version of the tattoo design 401 is seen at 402, this is representative of having selectively applied a laser to remove parts of the tattoo. The lines of tattoo 402 are thinner than the lines of tattoo 401, the lines are straight and the errors have been removed by laser removal. Figure 4b shows a representation of a solid colour tattoo 403 and the same tattoo with a subtractive design 404 produced by using a laser to selectively remove portions of the solid tattoo. Fine detail is shown at the centre of tattoo 404, this would be achieved by using a small laser spot size to remove tattoo ink. A thicker triangle is seen in 404, this would be achieved by using a larger laser spot size than for the fine detail. Within this specification, the term "about" means plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%. Within this specification, the term "substantially" means a deviation of plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%. Within this specification, reference to “substantially” includes reference to “completely” and / or “exactly”. That is, where the word substantially is included, it will be appreciated that this also includes reference to the particular sentence without the word substantially. It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications are covered by the appended claims. In this disclosure, when the subject of a phase is described as being "configured to" or “arranged to”, followed by a term defining a condition or function, this is used to indicate that the subject of the phrase is in a state in which it has that condition, or is able to perform that function, without the subject being modified or further configured. Some implementations may be described using the expressions “one / an embodiment” or “one / an example”, along with their derivatives. These terms mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Moreover, unless otherwise noted the features described above are recognized to be usable together in any combination. Thus, any features discussed separately may be employed in combination with each other unless it is noted that the features are incompatible with each other. The foregoing description of example embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the present disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future filed applications claiming priority to this application may claim the disclosed subject matter in a different manner and may generally include any set of one or more limitations as variously disclosed or otherwise demonstrated herein. Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein and vice versa. CLAUSES 1. A particle for a tattoo ink comprising: a mineral material; and a pigment; wherein the pigment is dispersed in the mineral material. 2. The particle as stated in clause 1, wherein the mineral material comprises a ceramic, preferably a biocompatible ceramic, preferably wherein the mineral material comprises metal oxides of aluminium, zirconium, silicon or a combination of two or more thereof, preferably wherein the metal oxides are modified by boron oxide, phosphorus oxide, fluorine, sodium oxide, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide or a combination of two or more thereof. 3. The particle as stated in clause 1 or 2, wherein the mineral material comprises calcium, magnesium, phosphorus, silicon or a combination of two or more thereof. 4. The particle as stated in any preceding clause, wherein the mineral material comprises a biomaterial, preferably a synthetic biomaterial. 5. The particle as stated in any preceding clause, wherein the mineral material is biocompatible. 6. The particle as stated in any preceding clause, wherein the mineral material comprises a plurality of interstices, preferably each particle contains at least about two interstices, preferably about 2 to about 2000 interstices, preferably about 10 to about 1000 interstices, preferably about 20 to about 500 interstices. 7. The particle as stated in clause 6, wherein the pigment is located in the interstices of the mineral material, preferably at least about 5% of the interstices comprise pigment, preferably about 5% to about 100%, preferably about 10% to about 90%, preferably about 20% to about 80%, preferably about 30% to about 70%. 8. The particle as stated in clause 6 or 7, wherein the interstices have an average diameter in the range of about 1 nm to about 500 nm, preferably about 5 nm to about 100 nm. 9. The particle as stated in any of clauses 6 to 8, wherein the interstices are distributed throughout the mineral material, preferably wherein the interstices are substantially homogenous throughout the mineral material. 10. The particle as stated in any of clauses 6 to 9, wherein the interstices are pores, preferably wherein the mineral material is porous 11. The particle as stated in any preceding clause, wherein the mineral material is substantially crystalline, preferably substantially polycrystalline. 12. The particle as stated in any preceding clause, wherein the mineral material forms a matrix structure, preferably wherein the pigment is located in the matrix structure, preferably wherein the pigment is located in interstices of the mineral matrix. 13. The particle as stated in any preceding clause, wherein the pigment is distributed throughout the particle, preferably wherein the pigment is distributed substantially homogeneously throughout the particle. 14. The particle as stated in any preceding clause, wherein the mineral material is coloured, preferably the mineral material is black, white, red, yellow, green, blue, orange, brown, pink, purple or a combination of two or more thereof. 15. The particle as stated in any preceding clause, wherein an external surface of the particle comprises pigment. 16. The particle as stated in any preceding clause, wherein the mineral material comprises a metal oxide, an alkali metal salt, an alkaline earth metal salt or a combination of two or more thereof, preferably the mineral material comprises an anionic fragment containing at least one of phosphorus, carbonate, sulfur, carbon, silicon, aluminium, or boron, and a cationic fragment containing at least one alkali metal element or alkaline earth metal element. 17. The particle as stated in any preceding clause, wherein the mineral material comprises a hydroxyapatite, lithium disilicate, calcium carbonate, an aluminium oxide, a zeolite, calcium glycerophosphate or a combination of two or more thereof, preferably a hydroxyapatite, preferably a calcium hydroxyapatite or a magnesium hydroxyapatite, or a combination thereof, preferably a calcium hydroxyapatite. . 18. The particle as stated in any preceding clause, wherein the mineral material has a solubility of less than 0.1 g / dL in water at 25 °C, preferably less than 0.01 g / dL in water at 25 °C. 19. The particle as stated in any preceding clause, wherein the particle does not comprise a polymer. 20. The particle as stated in any preceding clause, wherein the particle does not have a core-shell structure. 21. The particle as stated in any preceding clause, wherein the mineral material has an optical transmittance of more than about 50%, preferably wherein the optical transmittance of the mineral material is more than about 70%, preferably wherein the optical transmittance of the mineral material is more than about 90%. 22. The particle as stated in any preceding clause, wherein the pigment is substantially optically opaque. 23. The particle as stated in any preceding clause, wherein the particle has a D90 particle size between about 500 nm and about 500 pm, preferably the particle has a D90 particle size between about 1 pm and about 100 pm, preferably the particle has a D90 particle size between about 2 pm and about 50 pm. 24. The particle as stated in any preceding clause, wherein the mineral material has a substantially cubic microstructure or a substantially hexagonal microstructure. 25. The particle as stated in any preceding clause, wherein the pigment is a particulate pigment, preferably a nanoparticulate pigment, preferably wherein the particulate pigment has a D90 particle size between about 1 nm and about 100 nm, preferably between about 5 nm and about 60 nm, preferably about 10 nm. 26. The particle as stated in any preceding clause, wherein the pigment is selected from the group consisting of metal oxides, , carbon, , organic colourants or a combination of two or more thereof, preferably carbon black. 27. The particle as stated in any preceding clause, the particle being produced by comminution of a body comprising the mineral material and the pigment. 28. The particle as stated in any preceding clause, wherein the ratio of pigment to mineral material is about 0.1:99.9 to about 20:80 by weight, preferably wherein the ratio of pigment to mineral material is about 1:99 to about 15:85 by weight. 29. A tattoo ink composition comprising: the particles as stated in any of clauses 1 to 28; water; and an additive selected from a group consisting of: an antifoaming agent, a dispersant, a surfactant, a humectant, a rheological additive, a pharmacologically active agent, or a combination of two or more thereof. 30. The tattoo ink composition as stated in clause 29, wherein the antifoaming agent is an alcohol. 31. The tattoo ink composition as stated in clause 29 or 30, wherein the humectant is one or more selected from the group consisting of glycerol, hyaluronic acid, alpha-hydroxy acids, propylene glycol, panthenol, urea, and pyrrolidone carboxylic acids. 32. The tattoo ink composition as stated in any of clauses 29 to 31, comprising about 30 wt% to about 60 wt% water, preferably about 35 wt% to about 50 wt% water. 33. The tattoo ink composition as stated in any of clauses 29 to 32, comprising about 20 wt% to about 40 wt% of the particles. 34. The tattoo ink composition as stated in any of clauses 29 to 33, comprising about 5 wt% to about 30 wt% of the additive, preferably about 10 wt% to about 25 wt%. 35. A method of producing a particle for a tattoo ink comprising: synthesising a mineral material in the presence of a pigment; wherein in the particle the pigment is dispersed in the mineral material. 36. The method as stated in clause 35, wherein the synthesised mineral material comprises a plurality of interstices, and wherein the pigment is located in the plurality of interstices. 37. The method as stated in clause 35 or 36, wherein synthesising the mineral material comprises precipitating the mineral material in the presence of the pigment. 38. The method as stated in any of clauses 35 to 37, further comprising comminution of the mineral material. 39. The method as stated in any of clauses 35 to 38, wherein the particle is a microparticle. 40. The method according to any of clauses 35 to 39 further comprising the features of any of clauses 1 to 28. 41. A particle for a tattoo ink, wherein the particle is produced according to any of clauses 35 to 40. 42. Use of a particle according to any of clauses 1 to 29 or clause 41 in a tattoo ink. 43. A method of tattooing, comprising applying the tattoo ink according to any of clauses 29 to 34 to a human or animal. 44. The method of tattooing as stated in clause 43, wherein the tattoo ink is applied using a tattooing needle. 45. A method of removing a tattoo comprising: irradiating a tattoo comprising particles as stated in any of clauses 1 to 29 or 41 with an artificial light source. 46. The method as stated in clause 45, wherein the artificial light source is a laser, preferably having a wavelength of 1064 nm. 47. The method as stated in clause 46, wherein the laser has a wavelength of 1064 nm, a spot diameter of about 6 to 10 mm, a frequency of about 1 -10 Hz, and a power of about 200 MJ to about 800 MJ, preferably about 400 MJ to about 600 MJ, preferably about 500 MJ. 48. The method as stated in any of clauses 45 or 46, wherein the irradiation is by two or more lasers, the lasers having a combined power of about 200 MJ to about 800 MJ, preferably about 500 MJ.

Claims

1. A particle for a tattoo ink comprising:a mineral material; anda pigment;wherein the pigment is dispersed in the mineral material.

2. The particle as claimed in claim 1, wherein the mineral material comprises a ceramic, preferably a biocompatible ceramic, preferably wherein the mineral material comprises metal oxides of aluminium, zirconium, silicon or a combination of two or more thereof, preferably wherein the metal oxides are modified by boron oxide, phosphorus oxide, fluorine, sodium oxide, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide or a combination of two or more thereof.

3. The particle as claimed in claim 1 or 2, wherein the mineral material comprises calcium, magnesium, phosphorus, silicon or a combination of two or more thereof.

4. The particle as claimed in any preceding claim, wherein the mineral material is biocompatible.

5. The particle as claimed in any preceding claim, wherein the mineral material comprises a plurality of interstices, preferably each particle contains at least about two interstices, preferably about 2 to about 2000 interstices, preferably about 10 to about 1000 interstices, preferably about 20 to about 500 interstices.

6. The particle as claimed in claim 5, wherein the interstices are pores, preferably wherein the mineral material is porous.

7. The particle as claimed in any preceding claim, wherein the mineral material forms a matrix structure, preferably wherein the pigment is located in the matrix structure, preferably wherein the pigment is located in interstices of the mineral matrix.

8. The particle as claimed in any preceding claim, wherein an external surface of the particle comprises pigment.

9. The particle as claimed in any preceding claim, wherein the mineral material comprises a hydroxyapatite, lithium disilicate, calcium carbonate, an aluminium oxide, a zeolite, calcium glycerophosphate or a combination of two or more thereof, preferably a hydroxyapatite, preferably a calcium hydroxyapatite or a magnesium hydroxyapatite, or a combination thereof, preferably a calcium hydroxyapatite. .

10. The particle as claimed in any preceding claim, wherein the particle does not comprise a polymer.

11. The particle as claimed in any preceding claim, wherein the mineral material has an optical transmittance of more than about 50%, preferably wherein the optical transmittance of the mineral material is more than about 70%, preferably wherein the optical transmittance of the mineral material is more than about 90%.

12. The particle as claimed in any preceding claim, wherein the pigment is substantially optically opaque.

13. The particle as claimed in any preceding claim, wherein the particle has a D90 particle size between about 500 nm and about 500 pm, preferably the particle has a D90 particle size between about 1 pm and about 100 pm, preferably the particle has a D90 particle size between about 2 pm and about 50 pm.

14. The particle as claimed in any preceding claim, wherein the pigment is a particulate pigment, preferably a nanoparticulate pigment, preferably wherein the particulate pigment has a D90 particle size between about 1 nm and about 100 nm, preferably between about 5 nm and about 60 nm, preferably about 10 nm.

15. The particle as claimed in any preceding claim, wherein the pigment is selected from the group consisting of metal oxides, carbon, organic colourants or a combination of two or more thereof, preferably carbon black.

16. A tattoo ink composition comprising:the particles as claimed in any of claims 1 to 15;water; andan additive selected from a group consisting of: an antifoaming agent, a dispersant, a surfactant, a humectant, a rheological additive, a pharmacologically active agent, or a combination of two or more thereof.

17. The tattoo ink composition as claimed in claim 16, comprising about 30 wt% to about 60 wt% water, preferably about 35 wt% to about 50 wt% water.

18. The tattoo ink composition as claimed in any of claims 16 to 17, comprising about 20 wt% to about 40 wt% of the particles.

19. A method of producing a particle for a tattoo ink comprising:synthesising a mineral material in the presence of a pigment;wherein in the particle the pigment is dispersed in the mineral material.

20. The method as claimed in claim 19, wherein synthesising the mineral material comprises precipitating the mineral material in the presence of the pigment.

21. The method as claimed in any of claims 19 or 20, further comprising comminution of the mineral material.

22. A particle for a tattoo ink, wherein the particle is produced according to any of claims 19 to 21.

23. Use of a particle according to any of claims 1 to 15 or claim 22 in a tattoo ink.

24. A method of tattooing, comprising applying the tattoo ink according to any of claims 16 to 18 to a human or animal.

25. A method of removing a tattoo comprising:irradiating a tattoo comprising particles as claimed in any of claims 1 to 15 or 22 with an artificial light source.Application No: GB2400946.6Examiner: Mr Gareth ProtheroClaims searched: 1 to 25Date of search: 17 July 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1 to 8, 10 to 18, 23 to 25 US 2023 / 0320973 Al (BRUNS et al.) See especially figure 1, and paragraphs [0005] and [0049], X 1 to 8, 10 to 15 US 2016 / 0108244 A (KANE et al.) See especially the claims and paragraphs [0024] to [0026], X 1 to 8, 10 to 18, 23 to 25 US 2009 / 0271932 Al (ALBERIUS et al.) See especially the Examples, and paragraph [0050], X 1 to 18, 23 to 25 WO 2022 / 185348 Al (UNIV. MODENA) See especially page 13, line 23, to page 14, line 3; and claims 1 and 9. X 1 to 8, 10 to 15 JP 2013095888 A (JGC CATALYSTS) See WPI abstract accession no. 2013-H50918, and the machine translation.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:www.gov.uk / ipoInternational Classification:Subclass Subgroup Valid From A61K 0008 / 25 01 / 01 / 2006 A61K 0008 / 02 01 / 01 / 2006 A61K 0008 / 19 01 / 01 / 2006 A61K 0008 / 24 01 / 01 / 2006 A61Q 0001 / 02 01 / 01 / 2006 C09C 0001 / 00 01 / 01 / 2006 C09C 0001 / 02 01 / 01 / 2006 C09C 0001 / 28 01 / 01 / 2006 C09C 0003 / 06 01 / 01 / 2006www.gov.uk / ipo

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