Method and apparatus to enhance optical transparency of biological tissues

Abstract

Contemplated methods and compositions use selected agents to clarify biological tissues, and particularly tissues in vivo. In especially preferred aspects, the clarification agent is topically applied to clarify a plurality of layers, wherein the dermal layer that includes a target object remains unclarified. Light energy is then applied to the skin in an amount and under a protocol effective to destroy or alter the target object such that all skin layers avoid thermal damage. For example, hair follicles, collagen, and/or tattoo pigments located in the dermal reticular layer of skin are irradiated under a protocol in which the dermal papillary layer and all epidermal layers are clarified while the dermal reticular layer remains unclarified. Remarkably, such protocol significantly reduces thermal damage in the dermis, epidermis, and hypodermis.

1 . A method of irradiating a target object in skin comprising:
 providing a clarification agent in a topical formulation;   ascertaining that the target object is located in a sub-papillary layer of the skin, wherein the target further comprises a dye;   topically applying the clarifying agent to at least one layer of epidermis and a papillary layer of dermis under a protocol effective to achieve clarification of the at least one layer of epidermis and the papillary layer while providing substantially no clarification of the sub-papillary layer;   irradiating the skin with laser irradiation having visible light emission at a wavelength of less than 700 nm and at an energy effective to at least partially destroy the target object; and   wherein the step of irradiating is performed under a protocol effective to avoid thermal damage in the at least one layer of epidermis and the papillary layer.   
     
     
         2 . The method of  claim 1  wherein the clarification agent comprises at least one of glycerol, diatrizoate meglumine acid, and glucose. 
     
     
         3 . The method of  claim 1  wherein the step of topically applying is performed using application of at least one of heat, electrical current, and occlusion. 
     
     
         4 . The method of  claim 1  wherein the step of topically applying is performed without removal of at least one of stratum corneum and stratum lucidum. 
     
     
         5 . The method of  claim 1  wherein the topical formulation further includes a penetration enhancer. 
     
     
         6 . The method of  claim 1  wherein the sub-papillary layer of the skin is a reticular layer. 
     
     
         7 . The method of  claim 1  wherein the dye comprises a metal or melanin. 
     
     
         8 . The method of  claim 1  wherein the target object is selected from the group consisting of a hair follicle, a tattoo, a pigmented lesion, and collagen. 
     
     
         9 . The method of  claim 1  wherein the step of irradiating comprises irradiation with a laser having an emission wavelength of between 430 nm to 700 nm at an energy of between 10 W to 45 W. 
     
     
         10 . A kit comprising:
 a topical formulation for application to skin comprising a clarification agent in an amount effective to provide clarification of an epidermal layer of the skin and optionally a papillary layer of the skin when applied topically to the skin; and   an instruction to apply the formulation under a protocol effective to achieve clarification of at least one epidermal layer and optionally papillary layer of the skin while providing substantially no clarification of a sub-papillary layer of the skin.   
     
     
         11 . The kit of  claim 10  wherein the clarification agent comprises at least one of glycerol, diatrizoate meglumine acid, and glucose. 
     
     
         12 . The kit of  claim 10  wherein the formulation further includes a penetration enhancer. 
     
     
         13 . The kit of  claim 12  wherein the penetration enhancer is selected from the group consisting of sodium lauryl sulfate, sodium octyl sulfate, cetyl trimethyl ammonium bromide, dodecyl pyridinium chloride, octyl trimethyl ammonium bromide, hexadecyl trimethyl ammoniopropane sulfonate, oleyl betaine, cocamidopropyl hydroxysultaine, cocamidopropyl betaine, polyoxyethylene sorbitan monolaurate, sorbitan monolaurate, polyethyleneglycol dodecyl ether, Triton X-100, linoleic acid, linolenic acid, tetracaine, isopropyl myristate, sodium oleate, methyl laurate, N-decyl-2-pyrrolidone, dodecyl amine, nicotine sulfate, menthol, methyl pyrolidone, cineole, limonene, and ethanol. 
     
     
         14 . The kit of  claim 10  wherein the protocol includes reference to at least one of application of heat, application of an electric field, and application under occlusion. 
     
     
         15 . The kit of  claim 10  wherein the instruction further includes a reference to use the formulation in preparation for laser irradiation of a target disposed in a sub-papillary layer. 
     
     
         16 . The kit of  claim 15  wherein the target is selected from the group consisting of a hair follicle, a tattoo, a pigmented lesion, and collagen. 
     
     
         17 . A method of removing hair having a hair follicle, comprising:
 topically applying a clarification agent to skin such that at least one layer of epidermis and a papillary layer of dermis is clarified while substantially no clarification occurs in a sub-papillary layer of the skin; and   irradiating the hair follicle in the sub-papillary layer with visible laser light having a wavelength of above 700 nm at an energy effective to at least partially destroy the hair follicle.   
     
     
         18 . The method of  claim 17  wherein the step of topical application is performed without at least one of disruption and removal of at least another layer of the epidermis. 
     
     
         19 . The method of  claim 17  wherein the step of topically applying comprises application to an area of at least 200 cm 2 . 
     
     
         20 . The method of  claim 17  wherein the step of irradiating includes use of a green-blue laser at an energy of between 15 W to 40 W.