Permanent, removable tissue markings
View Patent ↗The present invention provides microparticles that create permanent tissue markings, such as tattoos, designed in advance for change and/or removal on demand, as well as methods for implanting the microparticles in tissue and changing and/or removing the resulting markings. Colored microparticles are constructed with specific electromagnetic absorption and/or structural properties that facilitate changing and/or removing tissue markings made using the microparticles by applying specific energy (such as electromagnetic radiation from a laser or flash-lamp) to the tissue marking site.
1. A tissue marking ink comprising:
a particle comprising:
(a) a chromophore, which is bleachable upon exposure to a bleaching agent; and
(b) a submicroparticle comprising a bleaching agent,
wherein the submicroparticle is ruptured upon exposure to a specific energy when the particle is within a tissue; and
a carrier.
2. The ink of claim 1 , wherein the bleaching agent is a peroxide, a hypochlorite, an excited oxygen species, or a free radical.
3. The ink of claim 1 , wherein the chromophore is pH-sensitive, and the bleaching agent is an acid, a base, or a buffer capable of effecting a pH transition within the particle to bleach the chromophore.
4. The ink of claim 1 , wherein the specific energy is electromagnetic radiation.
5. The ink of claim 1 , wherein the specific energy is infrared or near-infrared radiation.
6. The ink of claim 1 , wherein the chromophore has an average particle size of less than about 50 nm.
7. The ink of claim 1 , wherein the particle further comprises:
an indispersible, biologically inert coating; and
a core enveloped within the coating, wherein the core comprises the chromophore.
8. The ink of claim 7 , wherein the coating comprises a metal oxide, silica, glass, fluorocarbon resin, organic polymer, wax, or a combination thereof.
9. The ink of claim 1 , wherein the submicroparticle containing the bleaching agent or the coating enveloping the bleaching agent contains a discrete absorption component, which allows the bleaching agent to leach out and come into contact with the chromophore upon exposure to the specific energy.
10. The ink of claim 9 , wherein the discrete absorption component is selected from the group consisting of Schott filter glass, graphite, carbon, a metal oxide, an acrylate polymer, and a urethane polymer.
11. The ink of claim 1 , wherein the particle is from about 50 nm to about 100 microns in size.
12. The ink of claim 1 , wherein the particle is from about 15 nm to about 500 nm in size.
13. The ink of claim 1 , wherein the carrier comprises at least one of alcohol, water, or glycerin.
14. A method of applying a tissue marking, the method comprising:
providing the tissue marking ink of claim 1 ; and
implanting said ink into a tissue to form a tissue marking,
wherein an appearance of the chromophore changes upon exposure to a specific energy when the chromophore is within the tissue.
15. The method of claim 14 , wherein the specific energy is electromagnetic radiation.
16. The method of claim 14 , wherein the specific energy is infrared or near-infrared radiation.
17. A method for altering a tissue marking implanted in tissue, wherein the tissue marking comprises the ink of claim 1 , the method comprising exposing the tissue marking to the specific energy for a sufficient time to rupture the submicroparticle, thereby altering the appearance of the chromophore.
18. The method of claim 17 , wherein the specific energy is electromagnetic radiation.
19. The method of claim 17 , wherein the specific energy is infrared or near-infrared radiation.