WO2025212769A1

WO2025212769A1 - Colorimetric indicators and apparatus for treating topical lesions

Info

Publication number: WO2025212769A1
Application number: PCT/US2025/022744
Authority: WO
Inventors: Philip Michael Formica; Lincoln C. Young; Harpreet SEMBHI; Emma Young; R. Sam Niedbala
Original assignee: Cryoconcepts LP
Current assignee: Cryoconcepts LP
Priority date: 2024-04-02
Filing date: 2025-04-02
Publication date: 2025-10-09
Anticipated expiration: 2026-10-02

Abstract

The invention relates to a cryosurgical device and method that makes the application of cryogen to a targeted skin lesion on the surface of the skin for treatment more efficient and safer through the use of thermochromic principles. The thermochromic material within the cryosurgical device informs the operator when the cryosurgical device is ready to be used via a visual change of color in reaction to temperature changes. This color change prevents under or over dispensation of cryogen to the targeted skin lesion to allow for efficient yet safe treatment. After treatment of the area, the frozen tissue will necrose and slough off after a period of time and the thermochromic material will return to its original color.

Description

COLORIMETRIC INDICATORS AND APPARATUS FOR TREATING TOPICAL LESIONS

CROSS REFERENCE TO RELATED APPLICATION

[001] This application claims the benefit of U.S. Provisional Application No. 63/573,110 filed on April 2, 2024; the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

[002] The invention relates to devices for and methods of treating the skin using extreme cold to remove unwanted skin lesions. The invention further relates to devices that increase the ease and safety of use and operation of the device through use of thermochromic principles. Thermochromic materials may be used as indicators for those operating devices where cold gases must be properly dispensed and applied for use.

BACKGROUND OF THE INVENTION

[003] As the largest organ of the body, the skin has a number of functions; however, thermoregulation is one of the most important. The skin is composed of three major layers including the epidermis, the dermis, and subcutaneous tissue. The layers of the skin act, in part, to insulate the body against heat and water loss.

[004] Normally, tissue exists at a homeostatic or constant temperature. The human core temperature ranges from 97.7-99.5°F, with the surface temperature being several degrees cooler. When extreme cold is applied to the skin, any heat loss is offset for a time by the heat transfer from the surrounding tissue. When cryogen is applied for a sufficient period of time in a focused area and at a temperature exceeding the heat capacity for the tissue to return to homeostatic temperature, the tissue is frozen and a cryosurgical effect is achieved. Namely, the cryosurgical effect is the destruction of targeted tissue using extreme cold. The precise temperature when cryosurgical destruction is achieved is debated in the literature, but, generally, it can be achieved at temperatures below -20°C, with temperatures below -50°C being most effective. The goal of the treatment is to destroy the spot or targeted lesion where the extreme cold is applied; however, the overall effectiveness of the treatment is not only influenced by the low temperature, but also the hydration of the targeted lesion.

[005] Numerous types of benign lesions may be treated with cryosurgery and the peer reviewed literature is replete with many examples such as: verruca (warts), including flat, finger, vulgaris, plantar, and other superficial warts; lentigo (age spots); actinic keratoses (solar keratoses); seborrheic keratoses; achrochordon (skin tags); molluscum contagiosum; small keloids; dermatofibromas; keratocanthoma; granuloma annulare; angiomas; chondrodermatitis; epithelial nevus; porokeratosis plantaris discreta; leukoplakia; granuloma pyogenicum; and pyogenic granuloma.

[006] Warts are often discussed as a primary lesion treated using extreme cold or more commonly described as cryosurgery. Warts may be thickened and difficult to adequately freeze. Skin tags, in contrast, are soft and usually pedunculated. They can range in size from 2-6 mm and may or may not be pigmented. Skin tags pose no malignant threat, increase in number with age, and often appear where clothing rubs the skin. Being benign, they may simply be left alone; however, they are often removed for cosmetic reasons or because of irritation. The occurrence of skin tags in the general population is much higher than for warts, above 50%. A number of homeopathic treatments are available on the internet. However, when one reads the online reviews of these products and their poor performance, it is evident that they are not controlled or effective. Cryosurgical treatments, however, have been shown to be 100% effective when treating skin tags.

[007] Thermochromic materials are commonly used in a large number of commercial products designed to show hot or cold temperature changes. The thermochromic materials are often organic or metallic chemicals that tautomerize upon exposure to changes in temperature. The tautomerization reaction causes the molecules of the thermochromic materials to change conformation and, therefore, appear colored to the human eye. Once the temperature returns to the original temperature, the molecules of the thermochromic materials reorient molecularly and become invisible to the human eye. Leuco-dyes, which combine a colorant, an acid, and a solvent, are an example of organic thermochromic compounds. Pigments may also possess thermochromic properties wherein changes in temperature cause the pigment crystals to change shape, thereby absorbing light and appearing a different color.

[008] Freezing lesions using extreme cold is commonplace in physicians' offices as well as with over- the-counter consumer use. The process of freezing a targeted topical lesion depends upon application of the cryogen gas to the lesion for an adequate amount of time at the correct temperature. Cryosurgical treatments often require extremely cold gases to be dispensed onto applicators that are then applied to topical lesions to be treated. The operator of the device must manually track the dispense time of gas onto the applicator or risk excess gas dripping from the device causing harm to any non-targeted skin it touches, such as that of the operator or patient. There is also risk of dispensing too little cryogen and, therefore, not reaching the desired temperature or effect. Under-dispensation of the cryogen, or under- treatment, leads to dissatisfaction, while over-dispensation of the cryogen, or over-treatment, can lead to excessive damage to the targeted area or the healthy surrounding skin. The use of thermochromic materials in the device allows any operator assurance that sufficient cryogen is present upon application to the lesion. Since effectiveness of the treatment can be influenced by the operator of the device properly following instructions for use of the device, there is a need for making the process of freezing lesions more efficient and safer for the patient with the skin lesion which can be accomplished through the use of thermochromic materials. The color changing properties of the thermochromic materials help reduce operator errors while using the device.

SUMMARY OF THE INVENTION

[009] The invention relates to a cryosurgical device for the treatment of topical skin lesions that allows for more efficient treatment by visually informing the operator of the device that the device is ready for application to the targeted skin lesion. The cryosurgical device of the invention comprises a container of cryogen gas which dispenses a cryogen gas into an applicator, thus infusing the applicator with the cryogen. The applicator may comprise an enclosed area or a tip. The applicator may further comprise an applicator material. The cryogen-saturated applicator material or the cryogen-infused enclosed area or tip of the applicator is then positioned and applied to a targeted skin lesion. In some embodiments of the invention, the enclosed area or tip of the applicator is filled with cryogen. The cryosurgical device further comprises at least one thermochromic material that senses the presence of cryogen dispensed into the applicator and visually informs the operator of the device via at least one thermochromic indicator zone that the device is ready to be applied to the skin lesion by changing color. The at least one thermochromic material of the device may be located at various portions of the device and may be mixed into a materials matrix, for example foam or plastic, of the device or coated onto the external surface of the device. The at least one thermochromic indication zone is the portion where the color change from the at least one thermochromic material occurs. In some embodiments of the invention, at least one thermochromic material comprises organic chemicals. In some embodiments of the invention, at least one thermochromic material comprises crystalline inorganic material. In some embodiments of the invention, there is one thermochromic indication zone associated with one thermochromic material within or on one portion of the cryosurgical device. In some embodiments of the invention, there are two thermochromic indication zones associated with thermochromic materials within or on two portions of the cryosurgical device, wherein the thermochromic materials within or on the two portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are three thermochromic indication zones associated with thermochromic materials within or on three portions of the cryosurgical device, wherein the thermochromic materials within or on the three portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are four or more thermochromic indication zones associated with thermochromic materials within or on four or more portions of the cryosurgical device, wherein the thermochromic materials within or on the four or more portions of the cryosurgical device may be the same or different.

[0010] In all embodiments of the invention, the at least one thermochromic material is positioned within or on the device such that the associated at least one thermochromic indication zone is visible to the operator. The at least one thermochromic material is able to cycle color with each treatment performed. The device allows the at least one thermochromic material to provide operators of the device with added safety measures during operation to ensure an adequate amount of cryogen for treatment of the skin lesion without overexposing the skin of the patient to the cryogen.

[0011] The invention further relates to a cryosurgical device for the treatment of a skin lesion comprising an applicator, at least one thermochromic indication zone, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, and a container of cryogen gas. The at least one thermochromic material of the invention visually changes color when exposed to cryogen at a specific temperature.

[0012] The invention further relates to a cryosurgical device for the treatment of a skin lesion comprising an applicator receptacle, a cryogen applicator, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, at least one thermochromic indication zone, and a container of cryogen gas. The at least one thermochromic material of the invention visually changes color when exposed to cryogen at a specific temperature.

[0013] The invention further relates to a method for treatment of skin lesions using a cryosurgical skin lesion treatment device of the invention comprising at least one thermochromic material. The method involves dispensing cryogen gas into an applicator until the at least one thermochromic material within or on the device visually changes color via an at least one thermochromic indication zone indicating that the device is ready for application to the targeted skin lesion. The method further involves subsequently applying the cryogen-infused applicator to the targeted skin lesion, contacting the targeted skin lesion with the applicator, and removing the applicator from the targeted skin lesion after a period of time. [0014] The invention also relates to a kit comprising, consisting essentially of, or consisting of the cryosurgical devices comprising at least one thermochromic material disclosed herein.

BRIEF DESCRIPTION OF THE FIGURES

[0015] FIG. 1 shows an exemplary cryosurgical skin lesion treatment device including two possible thermochromic indication zones and a container of cryogen gas in accordance with the invention.

[0016] FIG. 2 shows an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone, a container of cryogen gas, and a cap to enclose an applicator in accordance with the invention.

[0017] FIG. 3A shows an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone, a container of cryogen gas, and a cap to enclose an applicator before dispensation of the cryogen gas in accordance with the invention.

[0018] FIG. 3B shows an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone, a container of cryogen gas, and a cap to enclose an applicator during dispensation of the cryogen gas in accordance with the invention.

[0019] FIG. 4A shows a cross-sectional view of an exemplary cryosurgical skin lesion treatment device including a foam reservoir, a metal tip, three possible thermochromic indication zones, an applicator, and a container of cryogen gas before dispensation of the cryogen gas in accordance with the invention.

[0020] FIG. 4B shows an exemplary cryosurgical skin lesion treatment device including a foam reservoir, a metal tip, three possible thermochromic indication zones, an applicator, and a container of cryogen gas before dispensation of the cryogen gas in accordance with the invention.

[0021] FIG. 4C shows a cross-sectional view of an exemplary cryosurgical skin lesion treatment device including a foam reservoir, a metal tip, three possible thermochromic indication zones, an applicator, and a container of cryogen gas after dispensation of the cryogen gas in accordance with the invention.

[0022] FIG. 4D shows an exemplary cryosurgical skin lesion treatment device including a foam reservoir, a metal tip, three possible thermochromic indication zones, an applicator, and a container of cryogen gas after dispensation of the cryogen gas in accordance with the invention.

[0023] FIG. 5A shows a cross-sectional view of an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone and a container of cryogen gas with an applicator placed into a receptacle on the device in accordance with the invention. [0024] FIG. 5B shows an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone and a container of cryogen gas with an applicator placed into a receptacle on the device in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] The invention relates to a skin lesion treatment device comprising at least one thermochromic material utilizing cryogen to treat topical skin lesions by way of freezing. The invention visually informs an operator when the device is ready to be applied to the targeted skin lesion through use of thermochromic principles. The invention utilizes thermochromic materials embedded into or coated onto various portions of the cryosurgical device which guide the operator on when the cryosurgical device is ready for use or when the cryosurgical device has been overexposed to cryogen resulting in excess gas being released. The thermochromic materials embedded into or coated onto various portions of the cryosurgical device may also inform the operator that the device has reached a temperature that is too warm for the desired use and, therefore, is not ready for use when the color change is detected and reverts back to its original color. The color changing properties of the thermochromic material minimize potential harm or ineffective treatment by preventing over-dispensation of the cryogen or under-dispensation of the cryogen, respectively. The use of thermochromic materials within a cryosurgical device does not affect the operation of the device or the temperatures reached within the device, nor does it affect the strength or functionality of the material, such as plastic or metal, of the device that come into contact with the cryogen. The invention further relates to the spatial placement of thermochromic materials to detect temperature for optimal application of the cryosurgical device. For example, the thermochromic material is placed at a location of the device where the temperature of the cryogen is optimal for application when the color change is detected. Conversely, the thermochromic material is placed at a location of the device where the temperature of the cryogen is no longer optimal for treatment when the color change is detected or reverts back to its original color.

[0026] The invention relates to a cryosurgical device for the treatment of topical skin lesions that allows for more efficient treatment by visually informing the operator of the device that the device is ready for application to the targeted skin lesion. The cryosurgical device of the invention comprises a container of cryogen gas which dispenses a cryogen gas into an applicator, thus infusing the applicator with the cryogen. The applicator may comprise an enclosed area or a tip. The applicator may further comprise an applicator material. The cryogen-saturated applicator material or the cryogen-infused enclosed area or tip of the applicator is then positioned and applied to a targeted skin lesion. The cryosurgical device further comprises at least one thermochromic material that senses the presence of cryogen dispensed into the applicator and visually informs the operator of the device via at least one thermochromic indicator zone that the device is ready to be applied to the skin lesion by changing color. The at least one thermochromic material of the device may be located at various portions of the device and may be mixed into a materials matrix, for example foam or plastic, of the device or coated onto the external surface of the device. The at least one thermochromic indication zone is the portion where the color change from the at least one thermochromic material occurs. In some embodiments of the invention, at least one thermochromic material comprises organic chemicals. In some embodiments of the invention, at least one thermochromic material comprises crystalline inorganic material. In some embodiments of the invention, there is one thermochromic indication zone associated with one thermochromic material within or on one portion of the cryosurgical device. In some embodiments of the invention, there are two thermochromic indication zones associated with thermochromic materials within or on two portions of the cryosurgical device, wherein the thermochromic materials within or on the two portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are three thermochromic indication zones associated with thermochromic materials within or on three portions of the cryosurgical device, wherein the thermochromic materials within or on the three portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are four or more thermochromic indication zones associated with thermochromic materials within or on four or more portions of the cryosurgical device, wherein the thermochromic materials within or on the four or more portions of the cryosurgical device may be the same or different.

[0027] The invention further relates to a cryosurgical device for the treatment of a skin lesion comprising an applicator, at least one thermochromic indication zone, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature. In one embodiment of the invention, the at least one thermochromic indication zone comprises the at least one thermochromic material wherein a color change is visible in the at least one thermochromic indication zone. In one embodiment of the invention, the at least one thermochromic material is spatially connected to the at least one thermochromic indication zone, wherein there is a delay in the color change while the color change from the at least one thermochromic material reaches the at least one thermochromic indication zone. In one embodiment of the invention, the applicator comprises an applicator shaft. In one embodiment of the invention, the applicator comprises an application tip or an enclosed area. In one embodiment of the invention, the applicator tip or the enclosed area is infused with cryogen from the container of cryogen gas. In one embodiment of the invention, the enclosed area or tip of the applicator is filled with cryogen. In one embodiment of the invention, the applicator further comprises an applicator material. In one embodiment of the invention, the applicator material is any material that can incorporate and retain the cryogen until application. In one embodiment of the invention, the applicator material is foam. In one embodiment of the invention, the applicator material is cotton. In one embodiment of the invention, the applicator material is saturated with cryogen from the container of cryogen gas. In one embodiment of the invention, the cryogen from the container of cryogen gas is dispensed into the applicator. In one embodiment of the invention, the applicator is attached to a top of the container of cryogen gas.

[0028] In one embodiment of the invention, the at least one portion with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone. In one embodiment of the invention, the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device. In one embodiment of the invention, the materials matrix of the at least one portion of the cryosurgical device is foam or plastic. In one embodiment of the invention, the cryosurgical device further comprises an applicator cap configured to enclose the applicator. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator cap. In one embodiment of the invention, the applicator tip is metal. In one embodiment of the invention, the metal tip is copper. In one embodiment of the invention, the metal tip is stainless steel. In one embodiment of the invention, the metal tip is tin. In one embodiment of the invention, the metal tip is zinc. In one embodiment of the invention, the metal tip is a metal other than copper, stainless steel, tin, or zinc. In one embodiment of the invention, the at least one thermochromic material is inked onto the metal tip. In one embodiment of the invention, the device further comprises a foam reservoir comprising foam, a portion of the applicator holds the foam reservoir in place, and the foam reservoir surrounds the metal tip. In one embodiment of the invention, the foam reservoir comprises multiple layers of foam. In one embodiment of the invention, the foam reservoir comprises cellulosic materials. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one the following: the portion of the applicator holding the foam reservoir in place, the foam reservoir, or the metal tip. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator shaft. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into the applicator tip or the enclosed area. In one embodiment of the invention, the at least one thermochromic material is disposed on or mixed into the applicator material. In one embodiment of the invention, the at least one thermochromic material comprises at least one organic chemical. In one embodiment of the invention, the at least one thermochromic material comprises at least one inorganic material. In one embodiment of the invention, the cryogen gas in the container is dispensed as a liquified cryogen gas. In one embodiment of the invention, the cryogen gas in the container is dispensed as an aerosol cryogen gas. In one embodiment of the invention, the visual color change of the at least one thermochromic material indicates that the cryosurgical device is ready for use.

[0029] The invention further relates to a cryosurgical device for the treatment of a skin lesion comprising an applicator receptacle, a cryogen applicator, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, at least one thermochromic indication zone, and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature. In one embodiment of the invention, the applicator receptacle is configured to accept the cryogen applicator. In one embodiment of the invention, the applicator receptacle is configured on the container of cryogen gas to accept cryogen from the container of cryogen gas. In one embodiment of the invention, the cryogen applicator is saturated with cryogen when accepted into the applicator receptacle. In one embodiment of the invention, the at least one thermochromic indication zone comprises the at least one thermochromic material wherein a color change is visible in the at least one thermochromic indication zone. In one embodiment of the invention, the at least one thermochromic material is connected to the at least one thermochromic indication zone, wherein there is a delay in the color change while the color change from the at least one thermochromic material reaches the at least one thermochromic indication zone. In one embodiment of the invention, one of the at least one thermochromic material is disposed on or mixed into the applicator receptacle. In one embodiment of the invention, the cryogen applicator is made of foam, cotton, other absorbent materials, or combinations thereof. In one embodiment of the invention, the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device. In one embodiment of the invention, the materials matrix of the at least one portion of the cryosurgical device is foam or plastic. In one embodiment of the invention, the at least one portion of the cryosurgical device with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone. In one embodiment of the invention, the at least one thermochromic material comprises at least one organic chemical. In one embodiment of the invention, the at least one thermochromic material comprises at least one inorganic material. In one embodiment of the invention, the cryogen gas in the container is dispensed as a liquified cryogen gas. In one embodiment of the invention, the cryogen gas in the container is dispensed as an aerosol cryogen gas. In one embodiment of the invention, the visual color change of the at least one thermochromic material indicates that the cryosurgical device is ready for use.

[0030] In some embodiments of the invention, the device allows for one-handed dispensation of the cryogen gas to an applicator by the operator. The applicator may be made of an absorbent material, such as cotton or a synthetic material, that is able to hold the cryogen. After dispensation of the cryogen to the absorbent applicator, the cryogen-saturated applicator is applied to the targeted skin lesion on the surface of the patient's skin to freeze and treat the targeted skin lesion. In some embodiments of the invention, the applicator of the device is an open receptacle that holds the cryogen gas so that it is shielded from ambient heat allowing the cryogen gas to remain at its boiling temperature for an extended period of time to increase exposure of the cryogen gas at its boiling temperature to the targeted skin lesion on the surface of the patient's skin during application.

[0031] In some embodiments of the invention, the device includes a lock and key mechanism to connect the applicator and the applicator cap of the device. The lock and key mechanism secures the applicator cap in place while the cryogen gas is dispensed into the applicator decreasing any heat loss during dispensation of the cryogen gas. In some embodiments of the invention, the device including the lock and key mechanism also includes at least one thermochromic material disposed on or mixed into the applicator cap. The lock and key mechanism secures the applicator cap in place ensuring consistent contact between the at least one thermochromic material disposed on or mixed into the applicator cap with the applicator in which the cryogen gas is being dispensed.

[0032] In some embodiments of the invention, the device includes an adaptor that attaches to the device that provides a guide for the operator to apply the device after dispensation of the cryogen gas to the targeted skin lesion on the surface of the patient's skin. In one embodiment of the invention, the operator applies the device with one hand using the adaptor. In another embodiment of the invention, the operator applies the device with two hands using the adaptor.

[0033] In some embodiments of the invention, the applicator tip of the device is an open spray tip that allows for application of the cryogen gas to the targeted skin lesion on the surface of the patient's skin in a spray form.

[0034] The invention may include a container of cryogen gas which dispenses cryogen gas into an applicator. In some embodiments of the invention, the applicator comprises an enclosed area or tip wherein the cryogen is dispensed into and around the enclosed area or tip which lowers the temperature of the enclosed area or tip for application to the targeted skin lesion. In some embodiments of the invention, the applicator comprises an applicator material which is saturated with cryogen. In some embodiments of the invention, the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R410A refrigerant (difluoromethane and pentafluoroethane), R404A refrigerant (pentafluoroethane, 1,1,1-trifluoroethane, and 1,1,2,2-tetrafluoroethane), R152A refrigerant (1,1- difluoroethane), carbon dioxide, nitrous oxide, and liquid nitrogen. In some embodiments of the invention, the container is filled with a composition of multiple cryogen gases. In some embodiments of the invention, the composition of cryogen gases is made of one or more of the following: dimethyl ether, propane, butane, R410A, R404A, R152A, carbon dioxide, nitrous oxide, and/or liquid nitrogen. In some embodiments of the invention, the cryogen gas is liquefied. In some embodiments of the invention, the cryogen gas is an aerosol.

[0035] The at least one thermochromic material present in the device senses the presence of cryogen dispensed into an applicator of the device and visually informs the operator of the device that the device is ready to be applied to the skin lesion by changing color based on a change in temperature. The at least one thermochromic material visually changes color based on the thermochromic material used and the temperature of the color change reaction. In some embodiments of the invention, the visual color change is instant. In some embodiments of the invention, the visual color change occurs within less than 5 seconds, less than 2 seconds, less than 1 second, or less than 0.5 seconds. The cryogen-saturated applicator material or cryogen-infused enclosed area or tip of the device is then applied to the targeted skin lesion. The time that cryogen-saturated applicator material or cryogen-infused enclosed area or tip of the device is applied to the targeted skin lesion is dependent on the size and location of the targeted skin lesion. In some embodiments of the invention, the cryogen-saturated applicator material or cryogen- infused enclosed area or tip of the device is applied to the targeted skin lesion for at least 5 seconds. The amount of time that the cryogen-saturated applicator material or cryogen-infused enclosed area or tip of the device is applied to the targeted skin lesion also depends on the type of cryogen used. In some embodiments of the invention, the cryogen-saturated applicator material or cryogen-infused enclosed area or tip of the device is applied to the targeted skin lesion for 40 seconds when dimethyl ether is used. In some embodiments of the invention, the cryogen-saturated applicator material or cryogen-infused enclosed area or tip of the device is applied to the targeted skin lesion for 10 seconds when nitrous oxide is used. The application of cryogen to a targeted skin lesion utilizing the invention results in the targeted skin lesion sloughing off the patient after a period of time. The sloughing off may take 2 weeks. The preferred end result of using the invention is the complete removal of the targeted skin lesion. The invention provides operators of the device with added safety measures during operation to ensure the proper amount of cryogen for adequate treatment of the skin lesion without overexposing the skin of the patient to the cryogen through use of thermochromic material within the device. In some embodiments of the invention, a single thermochromic material or multiple thermochromic materials emitting different colors visible to the human eye may be used together or in sequence. A spatially placed thermochromic material informs the operator that sufficient cryogen has been dispensed by changing color within the dispensation time period. In some embodiments of the invention, the dispensation time period ranges from 1-10 seconds to 3-5 seconds. In some embodiments of the invention, if the operator continues to dispense the cryogen past the prescribed dispensation time period, then excess cryogen may spill from the applicator, or the heat transfer of the dispensed cryogen may cause a second thermochromic material or second spatially placed thermochromic indication area to change color indicating that excess cryogen has been dispensed. In one embodiment of the invention, an applicator cap comprising at least one thermochromic material may catch excess cryogen that spills from the applicator and change color to a red color indicating that excess cryogen has been dispensed. In some embodiments of the invention, at the end of the treatment period or after excess cryogen has been dispensed, at least one thermochromic material reverts back to its original color indicating to the operator that the temperature of the applicator has risen above the effective treatment temperature and, therefore, the device is no longer at treatment temperature, or that the excess cryogen has evaporated and the device is safe and ready for use. The invention enables the treatment of topical skin lesions of various sizes while minimizing damage to surrounding healthy tissue. An operator of the device may be a health care professional or a general consumer. [0036] The invention relates to treatment of topical skin lesions. In some embodiments of the invention, the topical skin lesion is selected from the group consisting of verruca (warts), including flat, finger, vulgaris, plantar, and other superficial warts; lentigo (age spots); actinic keratoses (solar keratoses); seborrheic keratoses; achrochordon (skin tags); molluscum contagiosum; small keloids; dermatofibromas; keratocanthoma; granuloma annulare; angiomas; chondrodermatitis; epithelial nevus; porokeratosis plantaris discreta; leukoplakia; granuloma pyogenicum; pyogenic granuloma; and other topical skin lesions. In one embodiment of the invention, the topical skin lesion is verruca (warts), including flat, finger, vulgaris, plantar, and other superficial warts. In one embodiment of the invention, the topical skin lesion is lentigo (age spots). In one embodiment of the invention, the topical skin lesion is actinic keratoses (solar keratoses). In one embodiment of the invention, the topical skin lesion is seborrheic keratoses. In one embodiment of the invention, the topical skin lesion is achrochordon (skin tags). In one embodiment of the invention, the topical skin lesion is molluscum contagiosum. In one embodiment of the invention, the topical skin lesion is small keloids. In one embodiment of the invention, the topical skin lesion is dermatofibromas. In one embodiment of the invention, the topical skin lesion is keratocanthoma. In one embodiment of the invention, the topical skin lesion is granuloma annulare. In one embodiment of the invention, the topical skin lesion is angiomas. In one embodiment of the invention, the topical skin lesion is chondrodermatitis. In one embodiment of the invention, the topical skin lesion is epithelial nevus. In one embodiment of the invention, the topical skin lesion is porokeratosis plantaris discreta. In one embodiment of the invention, the topical skin lesion is leukoplakia. In one embodiment of the invention, the topical skin lesion is granuloma pyogenicum. In one embodiment of the invention, the topical skin lesion is pyogenic granuloma.

[0037] In some embodiments of the invention, the applicator tip of the device is a metal tip. In some embodiments of the invention, the metal tip is copper. In some embodiments of the invention, the applicator tip of the device is a plastic tip. In some embodiments of the invention, the applicator is a removeable cryogen applicator that is inserted into an applicator receptacle of the invention that is configured to accept the cryogen applicator. In some embodiments of the invention, the applicator is made of any material that can incorporate and retain the cryogen until application, including, but not limited to, foam, cotton, other absorbent materials, or combinations thereof. In some embodiments of the invention, the applicator tip of the device is an open spray tip.

[0038] The at least one thermochromic material of the device may be located at various portions of the device. In some embodiments of the invention, the at least one thermochromic material is an organic chemical. In some embodiments of the invention, the at least one thermochromic material is an inorganic chemical. In some embodiments of the invention, the at least one thermochromic material may be mixed into a materials matrix of the device, for example foam, plastic, or a resin or substrate forming the device components, or coated onto the external surface of the device. In some embodiments of the invention, the at least one thermochromic material is applied to the exterior of the device using adhesives, paints, or tapes. In some embodiments of the invention, the at least one thermochromic material is an organic dye. In some embodiments of the invention, the at least one thermochromic material is a metallic chemical. In some embodiments of the invention, the at least one thermochromic material is a crystalline inorganic material. In one embodiment of the invention, the at least one thermochromic material is a leuco-dye. In another embodiment of the invention, the at least one thermochromic material is a pigment crystal. In some embodiments of the invention, the at least one thermochromic material is one or more of an organic dye, a metallic chemical, a crystalline inorganic material, a leuco-dye, and a pigmented crystal. In some embodiments of the invention, the at least one thermochromic material is mixed with a secondary concentrate to mask undesirable room temperature tints of the device or to match the required device aesthetics. The secondary concentrate is mixed in such a way that it does not mask the color change of the thermochromic material. In some embodiments of the invention, the secondary concentrate is a white pigment. In some embodiments of the invention, the secondary concentrate is 1 %. In some embodiments of the invention, the secondary concentrate is 0.5 %. In some embodiments of the invention, the secondary concentrate is 0.25 %. In some embodiments of the invention, the secondary concentrate is 0 %. In some embodiments of the invention, the at least one thermochromic material is blue. In some embodiments of the invention, the at least one thermochromic material is green. In some embodiments of the invention, the at least one thermochromic material is red. In some embodiments of the invention, the at least one thermochromic material is yellow. In some embodiments of the invention, the at least one thermochromic material is green from the Matsui International Company, Inc.. In some embodiments of the invention, the at least one thermochromic material is red from the Matsui International Company, Inc.. In some embodiments of the invention, the thermochromic concentrate is 0.5 %. In some embodiments of the invention, the thermochromic concentrate is within the range of 1 % - 10 %. In some embodiments of the invention, the thermochromic concentrate is 1 %. In some embodiments of the invention, the thermochromic concentrate is 1.5 %. In some embodiments of the invention, the thermochromic concentrate is 3 %. In some embodiments of the invention, the thermochromic concentrate is 5 %. In some embodiments of the invention, the thermochromic concentrate is 8%. In some embodiments of the invention, the thermochromic concentrate is 10%. In one embodiment of the invention, the secondary concentrate is 1 % and the thermochromic concentrate is 0.5 %. In one embodiment of the invention, the secondary concentrate is 1 % and the thermochromic concentrate is 1 %. In one embodiment of the invention, the secondary concentrate is 0.5 % and the thermochromic concentrate is 1 %. In one embodiment of the invention, the secondary concentrate is 0 % and the thermochromic concentrate is 0.5 %. In one embodiment of the invention, the secondary concentrate is 0 % and the thermochromic concentrate is 1 %. In one embodiment of the invention, the secondary concentrate is 0.5 % and the thermochromic concentrate is 0.5 %. In one embodiment of the invention, the secondary concentrate is 0.5 % and the thermochromic concentrate is 1.5 %. In one embodiment of the invention, the secondary concentrate is 0.25 % and the thermochromic concentrate is 1.5 %. In one embodiment of the invention, the secondary concentrate is 0.5 % and the thermochromic concentrate is 3 %. In one embodiment of the invention, the secondary concentrate is 0 % and the thermochromic concentrate is 1.5 %.

[0039] The at least one thermochromic material of the invention is configured to change color at a specific temperature selected to indicate that the device is at least as cold as the boiling point of the dispensed cryogen gas, which is cold enough to freeze the targeted skin lesion. The at least one thermochromic material may also be configured to indicate early temperature changes of the device at which the device is not yet ready to be used by disposing of or mixing in at least one thermochromic material, for example, along the length of the applicator shaft. As the cryogen is dispensed from the container of cryogen gas into the applicator, the at least one thermochromic material will begin changing color as it is exposed to the cryogen and continue changing color down the length of the applicator shaft. In some embodiments of the invention, the at least one thermochromic material is configured to track the flow of cryogen thereby indicating early release. In some embodiments of the invention, the at least one thermochromic material changes color at a temperature within the range of -10 °C to 20 °C . In some embodiments of the invention, the at least one thermochromic material changes color at a temperature within the range of -5 °C to 20 °C. In some embodiments of the invention, the at least one thermochromic material changes color at a temperature within the range of 0 °C to 10 °C. In some embodiments of the invention, the at least one thermochromic material changes color at a temperature within the range of 0 °C to 5 °C. In some embodiments of the invention, the color change of the at least one thermochromic material occurs when the temperature goes below 0 °C indicating that the device is ready for use. In some embodiments of the invention, the color change of the at least one thermochromic material disappears at a temperature within the range of 10 °C to 20 °C. The at least one thermochromic material may also be configured to indicate that the device has been exposed to the cryogen for too long by including at least two thermochromic materials disposed on or mixed into at least two portions of the cryosurgical device to capture oversaturation and leakage of cryogen into other parts of the device.

[0040] In all embodiments of the invention, the at least one thermochromic indication zone is positioned within the device such that it is exposed to a position which is visible to the operator. In one embodiment of the invention, the at least one thermochromic indication zone comprises the at least one thermochromic material wherein a color change is visible in the at least one thermochromic indication zone. In one embodiment of the invention, the at least one thermochromic material is connected to the at least one thermochromic indication zone, wherein there is a delay in the color change while the color change from the at least one thermochromic material reaches the at least one thermochromic indication zone. In some embodiments of the invention, there is one thermochromic indication zone associated with one thermochromic material within or on one portion of the cryosurgical device. In some embodiments of the invention, there are two thermochromic indication zones associated with thermochromic materials within or on two portions of the cryosurgical device, wherein the thermochromic materials within or on the two portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are three thermochromic indication zones associated with thermochromic materials within or on three portions of the cryosurgical device, wherein the thermochromic materials within or on the three portions of the cryosurgical device may be the same or different. In some embodiments of the invention, there are four or more thermochromic indication zones associated with thermochromic materials within or on four or more portions of the cryosurgical device, wherein the thermochromic materials within or on the four or more portions of the cryosurgical device may be the same or different. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of a container of cryogen of the invention. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of an applicator of the invention. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of a shaft of the applicator. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of a tip or enclosed area of the applicator. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of a cap that encloses the applicator of the invention. In some embodiments of the invention, the at least one thermochromic material surrounds an applicator tip of the invention. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of the applicator holding the foam reservoir in place. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of the foam reservoir. In some embodiments of the invention, the at least one thermochromic material is disposed on a portion of the metal tip. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of the cryosurgical device adjacent to an area where the cryogen is dispensed to reflect the flow of cryogen onto the applicator. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into a portion of the applicator material. In some embodiments of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of one or more of the following: the application, the applicator shaft, the tip or enclosed area, the applicator material, the applicator cap, the foam reservoir, the portion of the applicator holding the foam reservoir in place, the metal tip, or any other portion of the cryosurgical device. In one exemplary embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator shaft and the applicator material. In one exemplary embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the foam reservoir and the portion of the applicator holding the foam reservoir in place. In one exemplary embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the foam reservoir, the portion of the applicator holding the foam reservoir in place, and the applicator tip. In one exemplary embodiment of the invention, the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator and the applicator cap. In some embodiments of the invention with two or more thermochromic materials, the thermochromic material colors are the same. In some embodiments of the invention with two or more thermochromic materials, the thermochromic material colors are the different at different portions of the cryosurgical device. In some embodiments of the invention, there is one or more thermochromic indication zones associated with one thermochromic material.

[0041] The invention can be used to treat skin lesions located anywhere on the dermis. In some embodiments of the invention, the targeted skin lesion is located on the neck. In some embodiments of the invention, the targeted skin lesion is located on the chest. In some embodiments of the invention, the targeted skin lesion is located on the hands. In some embodiments of the invention, the targeted skin lesion is located on the arms. In some embodiments of the invention, the targeted skin lesion is located on or around the groin. In some embodiments of the invention, the targeted skin lesion is located on or around the breasts. In some embodiments of the invention, the targeted skin lesion is located on or around the knees or feet.

[0042] The invention further relates to a method for treating skin lesions comprising providing a cryosurgical device of the invention, for example comprising an applicator, at least one thermochromic indication zone, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, and a container of cryogen gas; dispensing cryogen from the container of cryogen gas into the applicator; observing a visual color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen is dispensed into the applicator and reaches a temperature; applying the applicator to a targeted skin lesion of a patient when the at least one thermochromic material changes color; contacting the targeted skin lesion with the applicator; and removing the applicator tip from the targeted skin lesion after a period of time. In one embodiment of the invention, the period of time is greater than 1 second. In one embodiment of the invention, the temperature is less than 0 °C.

[0043] The invention further relates to a method for treating skin lesions comprising providing a cryosurgical device of the invention, for example comprising an applicator receptacle, a cryogen applicator, at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device, at least one thermochromic indication zone, and a container of cryogen gas; inserting the cryogen applicator into the applicator receptacle; dispensing cryogen from the container of cryogen gas into the applicator receptacle; saturating the cryogen applicator with the cryogen; observing a color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen applicator is saturated with the cryogen and reaches a temperature; removing the cryogen-saturated cryogen applicator from the applicator receptacle when the at least one thermochromic indication zone changes color; applying the cryogen-saturated cryogen applicator to a targeted skin lesion of a patient; contacting the targeted skin lesion with the cryogen from the cryogen-saturated cryogen applicator; and removing the cryogen applicator from the targeted skin lesion after a period of time. In one embodiment of the invention, the period of time is greater than 1 second. In one embodiment of the invention, the temperature is less than 0 °C.

[0044] FIG. 1 shows an exemplary cryosurgical skin lesion treatment device including at least two possible thermochromic indication zones and a container of cryogen gas. This exemplary embodiment of the invention shows that the at least one thermochromic material may be placed on various portions of the device within the thermochromic indication zones. The exemplary cryosurgical skin lesion treatment device 100 comprises an applicator tip 101, an applicator shaft 102, a spray cap 103, a container of cryogen gas 104, and two possible thermochromic material placement areas 105a and 105b (thermochromic indications zones). The at least one thermochromic material may be disposed onto or mixed into a portion of the spray cap 103, shown as placement area 105b, or within or onto a portion of the applicator shaft 102, shown placement area 105a. Cryogen gas releases from the container of cryogen gas 104 and travels through the spray cap 103 and the applicator shaft 102 into the applicator tip 101. While the cryogen gas travels to the applicator tip 101 from the container of cryogen gas 104, the at least one thermochromic material placed at placement area 105a is exposed to the cryogen gas and informs the operator that the device 100 is ready for use by visually changing color based on the temperature of the cryogen gas as the cryogen gas is dispensed from the container of cryogen gas through the applicator shaft. Once alerted by the visual color change of the at least one thermochromic material, the operator then applies the applicator tip 101 saturated with the cryogen gas to the targeted skin lesion on the surface of a patient's skin. The targeted skin lesion is then exposed to the cryogen gas for treatment. If the applicator tip 101 is overexposed to the cryogen and the cryogen leaks onto the spray cap 103, the thermochromic material placed at placement area 105b will change color alerting the operator of overexposure to the cryogen.

[0045] FIG. 2 shows an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone, a container of cryogen gas, and a cap to enclose an applicator. This exemplary embodiment of the invention shows that the at least one thermochromic material of the invention can be added to enclosures of the device, such as the cap to enclose the applicator. The exemplary cryosurgical skin lesion treatment device 200 comprises an applicator tip 201, an applicator shaft 202, a spray cap 203, a container of cryogen gas 204, a thermochromic material placement area 205 (thermochromic indication zone), and an applicator cap 206. The at least one thermochromic material is disposed on or mixed into a portion of the applicator cap 206 at the thermochromic material placement area 205. Cryogen gas releases from the container of cryogen gas 204 and travels through the spray cap 203 and the applicator shaft 202 into the applicator tip 201 which is enclosed by the applicator cap 206. While the cryogen gas travels to the applicator tip 201 from the container of cryogen gas 204, the at least one thermochromic material placed at placement area 205 within the applicator cap 206 is exposed to the cryogen gas and informs the operator that the device 200 is ready for use by visually changing color based on the temperature of the cryogen gas as the cryogen gas is dispensed into the applicator tip 201. Once alerted by the visual color change of the at least one thermochromic material within the applicator cap 206, the operator then removes the applicator cap 206 and applies the applicator tip 201 saturated with the cryogen gas to the targeted skin lesion on the surface of a patient's skin. The targeted skin lesion is then exposed to the cryogen gas for treatment.

[0046] FIG. 3A and 3B show an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone, a container of cryogen gas, and a cap to enclose an applicator before and during dispensation of the cryogen gas. The exemplary cryosurgical skin lesion treatment device 300 comprises an applicator 301, an applicator cap 302, and a cryogen container 303. FIG. 3A shows the device 300 before dispensation of the cryogen gas into the applicator 301. The applicator 301 is attached to the container of cryogen gas 303 and enclosed by the applicator cap 302. FIG. 3B shows the device 300 during dispensation of the cryogen gas. The operator uses downward force on the applicator cap 302 enclosing the applicator 301 in order to dispense cryogen gas from the container of cryogen gas 303 into the applicator 301. As the cryogen gas is dispensed, the at least one thermochromic material disposed on or mixed into the applicator 301 senses the temperature of the cryogen gas and visually changes color to inform the operator that the cryogen gas has been dispensed and the device 300 is ready for use. The operator would then remove the applicator cap 302 and apply the tip of the applicator 301 saturated with cryogen gas to the targeted skin lesion on the surface of a patient's skin. The targeted skin lesion is then exposed to the cryogen gas for treatment.

[0047] FIG. 4A-4D show cross-sectional views and normal views of an exemplary cryosurgical skin lesion treatment device including a foam reservoir, a metal tip, three possible thermochromic indication zones, and a container of cryogen gas before and after dispensation of the cryogen gas. The exemplary cryosurgical skin lesion treatment device 400 comprises a metal tip 401, a foam reservoir 402, which houses foam, an applicator 403, at least three possible thermochromic material placement areas 405a, 405b, and 405c (thermochromic indication zones), a container of cryogen gas 404. FIG. 4A and 4B show the device 400 before dispensation of the cryogen gas in a cross-sectional view (FIG. 4A) and a normal view (FIG. 4B). The metal tip 401 is surrounded by the foam in the foam reservoir 402. The cryogen gas is dispensed from the container of cryogen gas 404 into the metal tip 401. The cryogen overflows the metal tip and soaks the foam of the foam reservoir 402. The cryogen gas lowers the temperature of the metal tip 401 below -20 °C. The portion of the applicator 403 which holds the foam reservoir 402 in place may contain at least one thermochromic material placed at placement area 405a. The foam of the foam reservoir may also include at least one thermochromic material 405b. The metal tip 401 may also include at least one thermochromic material 405c. The at least one thermochromic materials 405a, 405b, and/or 405c detect the temperature change and informs the operator that the device 400 is ready for use by visually changing color, as shown in FIG. 4C and 4D, which show a cross-sectional view (FIG. 4C) and a normal view (FIG. 4D) of the device 400 after dispensation of the cryogen gas. For example, the at least one thermochromic material 405b turns blue to inform the operator that the desired amount of cryogen gas has been dispensed and the device 400 is ready for use. The operator would then apply the metal tip 401 to the targeted skin lesion on the surface of the patient's skin. The targeted skin lesion is then exposed to the cryogen gas for treatment.

[0048] In some embodiments of the invention, the cryogen gas is dispensed into the foam of the foam reservoir 402 surrounding the metal tip 401. The foam fills with the cryogen gas and the at least one thermochromic material disposed on or mixed into the foam 405b senses the presence of the cryogen gas by the change in temperature and informs the operator that the device 400 is ready for use by visually changing color. The rapid evaporation of the cryogen gas from the foam cools the metal tip 401 to the desired treatment temperature. The operator would then apply the cooled metal tip 401 to the targeted skin lesion on the surface of the patient's skin to freeze the targeted skin lesion.

[0049] FIG. 5A and 5B show a cross-sectional and normal view of an exemplary cryosurgical skin lesion treatment device including a thermochromic indication zone and a container of cryogen gas with an applicator placed into a receptacle on the device. This exemplary embodiment of the cryosurgical skin lesion treatment device is designed to work in conjunction with a removeable applicator. The exemplary cryosurgical skin lesion treatment device 500 comprises an applicator receptacle 501 configured to accept an applicator 502, a thermochromic component 503 (visible in FIG. 5A but not fully visible in FIG. 5B), thermochromic indication zones 504 (only one is visible in FIG. 5A and two are visible in FIG. 5B), and a container of cryogen gas 505. The applicator 502 is placed into the applicator receptacle 501, which is attached to the container of cryogen gas 505, by the operator. After placement of the applicator 502, the cryogen gas is dispensed from the container of cryogen gas 505 into the applicator receptacle 501 by downward force on the cap of the container of cryogen gas. The thermochromic component 503 of the applicator receptacle comprises at least one thermochromic material. In some embodiments, the thermochromic component 503 is contained inside the applicator receptacle 501. As shown in FIG. 5A, the thermochromic component 503 is exposed to the cryogen gas and visually informs the operator that the device 500 is ready for use via the thermochromic indication zones 504, as shown in FIG. 5B, by visually changing color. In this embodiment, the thermochromic component 503 and the thermochromic indication zones 504 are spatially placed so that the cryogen is not directly exposed to the thermochromic indication zones 504. There is a delay as the color change travels from the thermochromic component 503 to the thermochrorriic indication zones 504. The placement of the thermochromic indication zones

504 is located an appropriate distance away from the thermochromic component 503 so that by the time the color change reaches the thermochromic indication zones 504 the temperature of the applicator 502 is ready to use. For example, the thermochromic indicator zones 504 turn blue to inform the operator that the device 500 is ready for use. The operator would then remove the applicator 502 soaked in cryogen from the applicator receptacle 501 and apply the cryogen-soaked applicator 502 directly to the targeted skin lesion on the surface of a patient's skin. The targeted skin lesion is then exposed to the cryogen gas for treatment.

[0050] The invention further provides a kit comprising, consisting of, or consisting essentially of the cryosurgical device disclosed herein; and instructions for administration of the cryosurgical device. As used herein, the term "instructions" when used in the context of a kit includes a publication, a recording, a diagram, or any other medium of expression which can be used to communicate the usefulness of the kit for its designated use. The instructions can, for example, be affixed to or included within a container for the kit. The applicator, applicator cap, applicator tip, applicator shaft, applicator material, thermochromic component, at least one thermochromic material, at least one thermochromic indication zone, foam reservoir, applicator receptacle, and/or the container of cryogen gas may be sealed as separate articles (i.e., fully or partially disassembled) or may be combined into one or more articles of manufacture (i.e., fully or partially assembled). The applicator, applicator cap, applicator tip, applicator shaft, applicator material, thermochromic component, at least one thermochromic material, at least one thermochromic indication zone, foam reservoir, applicator receptacle, and/or the container of cryogen gas may also be packaged as separate articles of manufacture. For example, the applicator, applicator cap, applicator tip, application shaft, applicator material, at least one thermochromic material, at least one thermochromic indication zone, foam reservoir, applicator receptacle, and/or thermochromic component, may be packaged as a first article of manufacture, and the container of cryogen gas may be packaged as a second article of manufacture. Individual components of the cryosurgical device may be packaged as their own articles of manufacture as well. Furthermore, more than one of any component of the cryosurgical device and optional container of cryogen gas may be packaged in a single article of manufacture. For example, one article of manufacture may contain two or more cryogen applicators for more than one treatment application.

[0051] The term "container" as used herein refers to any receptacle or applicator means capable of holding, storing, and/or applying the cryogen disclosed herein. Such a container may be in any container configuration known to a person skilled in the art, such as, but not limited to, a canister. The containers may be made of any material suitable for the materials contained therein and additionally suitable for short- and/or long-term storage under any kind of temperature. Such materials include, by way of example, inorganic materials, such as Type I glass (including amber colored glass), ceramics, metals (e.g., steel, aluminum, tin), etc., and organic materials such as inert polymers including polyolefins (e.g., high density polyethylene), fluorinated polyolefins, and the like. Suitable containers include those that maintain the sterility and integrity of their contents, for example, by providing a barrier to moisture.

[0052] The term "disposed on" as used herein refers to any means for applying or depositing the at least one thermochromic material onto the desired portion of the cryosurgical device. For example, the at least one thermochromic material disclosed herein can be applied to the desired portion of the cryosurgical device by any method known in the art, including, without limitation, compounding, coating, painting, inking, spraying, brushing, dipping, taping, printing, or rolling, or mixed into desired portions of the cryosurgical device. The at least one thermochromic material can be applied onto the desired portion of the cryosurgical device using various tools and equipment, including, without limitation, a paint brush, a spray gun, a roller, or a dispensing system.

[0053] Exemplary Embodiments of the Invention

[0054] El. A cryosurgical device for the treatment of a skin lesion comprising: an applicator; at least one thermochromic indication zone; at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device; and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature.

[0055] E2. The cryosurgical device of El, wherein the at least one thermochromic indication zone comprises the at least one thermochromic material.

[0056] E3. The cryosurgical device of El, wherein the at least one thermochromic material is connected to the at the least one thermochromic indication zone.

[0057] E4. The cryosurgical device of any one of E1-E3, wherein the applicator comprises an applicator shaft. [0058] E5. The cryosurgical device of any one of E1-E4, wherein the applicator comprises an applicator tip or an enclosed area.

[0059] E6. The cryosurgical device of any one of E1-E5, wherein the applicator further comprises an applicator material.

[0060] E7. The cryosurgical device of any one of E1-E6, wherein cryogen from the container of cryogen gas is dispensed into the applicator.

[0061] E8. The cryosurgical device of E6, wherein the applicator material is saturated with cryogen from the container of cryogen gas.

[0062] E9. The cryosurgical device of any one of E1-E8, wherein the applicator is attached to a top of the container of cryogen gas.

[0063] E10. The cryosurgical device of any one of E1-E9, wherein the at least one portion of the cryosurgical device with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone.

[0064] Ell. The cryosurgical device of any one of E1-E10, wherein the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device.

[0065] E12. The cryosurgical device of Ell, wherein the materials matrix of the at least one portion of the cryosurgical device is foam or plastic.

[0066] E13. The cryosurgical device of any one of E1-E12, wherein the cryosurgical device further comprises an applicator cap configured to enclose the applicator.

[0067] E14. The cryosurgical device of E13, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator cap.

[0068] E15. The cryosurgical device of E5, wherein the applicator tip is metal.

[0069] E16. The cryosurgical device of E15, wherein the cryosurgical device further comprises a foam reservoir comprising foam, wherein a portion of the applicator holds the foam reservoir in place, and wherein the foam reservoir surrounds the metal tip.

[0070] E17. The cryosurgical device of E16, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of at least one of the following: the portion of the applicator holding the foam reservoir in place; the foam reservoir; or the metal tip.

[0071] E18. The cryosurgical device of any one of E1-E17, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator.

[0072] E19. The cryosurgical device of E4, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator shaft.

[0073] E20. The cryosurgical device of E5, wherein the at least one thermochromic material is disposed on or mixed into the applicator tip or the enclosed area.

[0074] E21. The cryosurgical device of E6, wherein the at least one thermochromic material is disposed on or mixed into the applicator material.

[0075] E22. The cryosurgical device of any one of E1-E21, wherein the skin lesion is selected from a verruca (warts), lentigo (age spots), actinic keratoses (solar keratoses), seborrheic keratoses, achrochordon (skin tags), molluscum contagiosum, small keloids, dermatofibromas, keratocanthoma, granuloma annulare, angiomas, chondrodermatitis, epithelial nevus, porokeratosis plantaris discreta, leukoplakia, granuloma pyogenicum, pyogenic granuloma, and other topical skin lesions.

[0076] E23. The cryosurgical device of any one of E1-E22, wherein the at least one thermochromic material comprises at least one organic chemical.

[0077] E24. The cryosurgical device of any one of E1-E22, wherein the at least one thermochromic material comprises at least one inorganic material.

[0078] E25. The cryosurgical device of any one of E1-E24, wherein the cryogen gas in the container is dispensed as a liquified cryogen gas.

[0079] E26. The cryosurgical device of any one of E1-E24, wherein the cryogen gas in the container is dispensed as an aerosol cryogen gas.

[0080] E27. The cryosurgical device of any one of E1-E26, wherein the visual color change of the at least one thermochromic material indicates that the cryosurgical device is ready for use.

[0081] E28. The cryosurgical device of any one of E1-E27, wherein the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and liquid nitrogen.

[0082] E29. The cryosurgical device of any one of E1-E27, wherein the cryogen gas is a composition of one or more of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and/or liquid nitrogen.

[0083] E30. A cryosurgical device for the treatment of a skin lesion comprising: an applicator receptacle; a cryogen applicator; at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device; at least one thermochromic indication zone; and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature.

[0084] E31. The cryosurgical device of E30, wherein the applicator receptacle is configured to accept the cryogen applicator.

[0085] E32. The cryosurgical device of E30 or E31, wherein the applicator receptacle is configured on the container of cryogen gas to accept cryogen from the container of cryogen gas.

[0086] E33. The cryosurgical device of E31 or E32, wherein the cryogen applicator is saturated with cryogen when accepted into the applicator receptacle.

[0087] E34. The cryosurgical device of any one of E30-E33, wherein the at least one thermochromic indication zone comprises the at least one thermochromic material.

[0088] E35. The cryosurgical device of any one of E30-E33, wherein the at least one thermochromic material is connected to the at the least one thermochromic indication zone.

[0089] E36. The cryosurgical device of any one of E30-E35, wherein one of the at least one thermochromic material is disposed on or mixed into the applicator receptacle.

[0090] E37. The cryosurgical device of any one of E30-E36, wherein the cryogen applicator is made of foam, cotton, other absorbent materials, or combinations thereof.

[0091] E38. The cryosurgical device of any one of E30-E37, wherein the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device.

[0092] E39. The cryosurgical device of E38, wherein the materials matrix of the at least one portion of the cryosurgical device is foam or plastic.

[0093] E40. The cryosurgical device of E30-E39, wherein the at least one portion of the cryosurgical device with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone. [0094] E41. The cryosurgical device of any one of E30-E40, wherein the skin lesion is selected from the group consisting of a verruca (warts), lentigo (age spots), actinic keratoses (solar keratoses), seborrheic keratoses, achrochordon (skin tags), molluscum contagiosum, small keloids, dermatofibromas, keratocanthoma, granuloma annulare, angiomas, chondrodermatitis, epithelial nevus, porokeratosis plantaris discreta, leukoplakia, granuloma pyogenicum, pyogenic granuloma, and other topical skin lesions.

[0095] E42. The cryosurgical device of any one of E30-E41, wherein the at least one thermochromic material comprises at least one organic chemical.

[0096] E43. The cryosurgical device of any one of E30-E41, wherein the at least one thermochromic material comprises at least one inorganic material.

[0097] E44. The cryosurgical device of any one of E30-E43, wherein the cryogen gas in the container is dispensed as a liquified cryogen gas.

[0098] E45. The cryosurgical device of any one of E30-E43, wherein the cryogen gas in the container is dispensed as an aerosol cryogen gas.

[0099] E46. The cryosurgical device of any one of E30-E45, wherein the visual color change of the at least one thermochromic material indicates that the cryosurgical device is ready for use.

[00100] E47. The cryosurgical device of any one of E30-E46, wherein the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and liquid nitrogen.

[00101] E48. The cryosurgical device of any one of E30-E46, wherein the cryogen gas is a composition of one or more of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and/or liquid nitrogen.

[00102] E49. A method for treating skin lesions, the method comprising: providing the cryosurgical device of any one of E1-E29; dispensing cryogen from the container of cryogen gas into the applicator; observing a visual color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen is dispensed to the applicator and reaches a temperature; applying the applicator to a targeted skin lesion of a patient when the at least one thermochromic material changes color; contacting the targeted skin lesion with the applicator; and 1 removing the applicator from the targeted skin lesion after a period of time.

[00103] E50. The method of E49, wherein the period of time is greater than 1 second.

[00104] E51. The method of E49 or E50, wherein the temperature is less than 0 °C.

[00105] E52. The method of any one of E49-E51, wherein the targeted skin lesion is topically located on the patient.

[00106] E53. A method for treating skin lesions, the method comprising: providing the cryosurgical device of any one of E30-E48; inserting the cryogen applicator into the applicator receptacle; dispensing cryogen from the container of cryogen gas into the applicator receptacle; saturating the cryogen applicator with the cryogen; observing a color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen applicator is saturated with the cryogen and reaches a temperature; removing the cryogen-saturated cryogen applicator from the applicator receptacle when the at least one thermochromic indication zone changes color; applying the cryogen-saturated cryogen applicator to a targeted skin lesion of a patient; contacting the targeted skin lesion with the cryogen from the cryogen-saturated cryogen applicator; and removing the cryogen applicator from the targeted skin lesion after a period of time.

[00107] E54. The method of E53, wherein the period of time is greater than 1 second.

[00108] E55. The method of E53 or E54, wherein the temperature is less than 0 °C.

[00109] E56. The method of any one of E53-E55, wherein the targeted skin lesion is topically located on the patient.

[00110] E57. The method of any one of E53-E56, wherein the cryogen applicator is made of foam, cotton, other absorbent materials, or combinations thereof.

[00111] E58. The method of any one of E49-E57, wherein the targeted skin lesion is selected from the group consisting of a verruca (warts), lentigo (age spots), actinic keratoses (solar keratoses), seborrheic keratoses, achrochordon (skin tags), molluscum contagiosum, small keloids, dermatofibromas, keratocanthoma, granuloma annulare, angiomas, chondrodermatitis, epithelial nevus, porokeratosis plantaris discrete, leukoplakia, granuloma pyogenicum, pyogenic granuloma, and other topical skin lesions. [00112] E59. The method of any one of E49-E58, wherein the at least one thermochromic material comprises at least one organic chemical.

[00113] E60. The method of any one of E49-E58, wherein the at least one thermochromic material comprises at least one inorganic material.

[00114] E61. The method of any one of E49-E60, wherein the cryogen gas in the container is a liquified cryogen gas.

[00115] E62. The method of any one of E49-E60, wherein the cryogen gas in the container is dispensed as an aerosol cryogen gas.

[00116] E63. The method of any one of E49-E62, wherein the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and liquid nitrogen.

[00117] E64. The method of any one of E49-E62, wherein the cryogen gas is a composition of one or more of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and/or liquid nitrogen.

[00118] E65. A kit comprising the cryosurgical device of any one of E1-E48.

[00119] E66. The kit of E67, wherein the cryosurgical device is partially or fully preassembled.

[00120] E67. The kit of E67, wherein the cryosurgical device is disassembled.

Claims

The claimed invention is:

1. A cryosurgical device for the treatment of a skin lesion comprising: an applicator; at least one thermochromic indication zone; at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device; and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature.

2. The cryosurgical device of claim 1, wherein the at least one thermochromic indication zone comprises the at least one thermochromic material.

3. The cryosurgical device of claim 1, wherein the at least one thermochromic material is connected to the at the least one thermochromic indication zone.

4. The cryosurgical device of claim 1, wherein the applicator comprises an applicator shaft.

5. The cryosurgical device of claim 1, wherein the applicator comprises an applicator tip or an enclosed area.

6. The cryosurgical device of claim 1, wherein the applicator further comprises an applicator material.

7. The cryosurgical device of claim 1, wherein cryogen from the container of cryogen gas is dispensed into the applicator.

8. The cryosurgical device of claim 6, wherein the applicator material is saturated with cryogen from the container of cryogen gas.

9. The cryosurgical device of claim 1, wherein the applicator is attached to a top of the container of cryogen gas.

10. The cryosurgical device of claim 1, wherein the at least one portion of the cryosurgical device with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone.

11. The cryosurgical device of claim 1, wherein the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device.

12. The cryosurgical device of claim 11, wherein the materials matrix of the at least one portion of the cryosurgical device is foam or plastic.

13. The cryosurgical device of claim 1, wherein the cryosurgical device further comprises an applicator cap configured to enclose the applicator.

14. The cryosurgical device of claim 13, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator cap.

15. The cryosurgical device of claim 5, wherein the applicator tip is metal.

16. The cryosurgical device of claim 15, wherein the cryosurgical device further comprises a foam reservoir comprising foam, wherein a portion of the applicator holds the foam reservoir in place, and wherein the foam reservoir surrounds the metal tip.

17. The cryosurgical device of claim 16, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of at least one of the following: the portion of the applicator holding the foam reservoir in place; the foam reservoir; or the metal tip.

18. The cryosurgical device of claim 1, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator.

19. The cryosurgical device of claim 4, wherein the at least one thermochromic material is disposed on or mixed into at least one portion of the applicator shaft.

20. The cryosurgical device of claim 5, wherein the at least one thermochromic material is disposed on or mixed into the applicator tip or the enclosed area.

21. The cryosurgical device of claim 6, wherein the at least one thermochromic material is disposed on or mixed into the applicator material.

22. A cryosurgical device for the treatment of a skin lesion comprising: an applicator receptacle; a cryogen applicator; at least one thermochromic material disposed on or mixed into at least one portion of the cryosurgical device; at least one thermochromic indication zone; and a container of cryogen gas, wherein the at least one thermochromic material visually changes color when exposed to cryogen at a specific temperature.

23. The cryosurgical device of claim 22, wherein the applicator receptacle is configured to accept the cryogen applicator.

24. The cryosurgical device of claim 22, wherein the applicator receptacle is configured on the container of cryogen gas to accept cryogen from the container of cryogen gas.

25. The cryosurgical device of claim 23, wherein the cryogen applicator is saturated with cryogen when accepted into the applicator receptacle.

26. The cryosurgical device of claim 22, wherein the at least one thermochromic indication zone comprises the at least one thermochromic material.

27. The cryosurgical device of claim 22, wherein the at least one thermochromic material is connected to the at the least one thermochromic indication zone.

28. The cryosurgical device of claim 22, wherein one of the at least one thermochromic material is disposed on or mixed into the applicator receptacle.

29. The cryosurgical device of claim 22, wherein the cryogen applicator is made of foam, cotton, other absorbent materials, or combinations thereof.

30. The cryosurgical device of claim 22, wherein the at least one thermochromic material is mixed into a materials matrix of the at least one portion of the cryosurgical device or coated onto a surface of the at least one portion of the cryosurgical device.

31. The cryosurgical device of claim 30, wherein the materials matrix of the at least one portion of the cryosurgical device is foam or plastic.

32. The cryosurgical device of claim 22, wherein the at least one portion of the cryosurgical device with the at least one thermochromic material is visible to an operator of the cryosurgical device via the at least one thermochromic indication zone.

33. The cryosurgical device of any one of claims 1-32, wherein the skin lesion is selected from the group consisting of a verruca (warts), lentigo (age spots), actinic keratoses (solar keratoses), seborrheic keratoses, achrochordon (skin tags), molluscum contagiosum, small keloids, dermatofibromas, keratocanthoma, granuloma annulare, angiomas, chondrodermatitis, epithelial nevus, porokeratosis plantaris discreta, leukoplakia, granuloma pyogenicum, pyogenic granuloma, and other topical skin lesions.

34. The cryosurgical device of any one of claims 1-32, wherein the at least one thermochromic material comprises at least one organic chemical.

35. The cryosurgical device of any one of claims 1-32, wherein the at least one thermochromic material comprises at least one inorganic material.

36. The cryosurgical device of any one of claims 1-32, wherein the cryogen gas in the container is dispensed as a liquified cryogen gas.

37. The cryosurgical device of any one of claims 1-32, wherein the cryogen gas in the container is dispensed as an aerosol cryogen gas.

38. The cryosurgical device of any one of claims 1-32, wherein the visual color change of the at least one thermochromic material indicates that the cryosurgical device is ready for use.

39. The cryosurgical device of claim 1 or claim 22, wherein the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and liquid nitrogen.

40. The cryosurgical device of claim 1 or claim 22, wherein the cryogen gas is a composition of one or more of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and/or liquid nitrogen.

41. A method for treating skin lesions, the method comprising: providing the cryosurgical device of claim 1; dispensing cryogen from the container of cryogen gas into the applicator; observing a visual color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen is dispensed to the applicator and reaches a temperature; applying the applicator to a targeted skin lesion of a patient when the at least one thermochromic material changes color; contacting the targeted skin lesion with the applicator; and removing the applicator from the targeted skin lesion after a period of time.

42. The method of claim 41, wherein the period of time is greater than 1 second.

43. The method of claim 41, wherein the temperature is less than 0 °C.

44. The method of claim 41, wherein the targeted skin lesion is topically located on the patient.

45. A method for treating skin lesions, the method comprising: providing the cryosurgical device of claim 22; inserting the cryogen applicator into the applicator receptacle; dispensing cryogen from the container of cryogen gas into the applicator receptacle; saturating the cryogen applicator with the cryogen; observing a color change of the at least one thermochromic material via the at least one thermochromic indication zone as the cryogen applicator is saturated with the cryogen and reaches a temperature; removing the cryogen-saturated cryogen applicator from the applicator receptacle when the at least one thermochromic indication zone changes color; applying the cryogen-saturated cryogen applicator to a targeted skin lesion of a patient; contacting the targeted skin lesion with the cryogen from the cryogen-saturated cryogen applicator; and removing the cryogen applicator from the targeted skin lesion after a period of time.

46. The method of claim 45, wherein the period of time is greater than 1 second.

47. The method of claim 45, wherein the temperature is less than 0 °C.

48. The method of claim 45, wherein the targeted skin lesion is topically located on the patient.

49. The method of claim 45, wherein the cryogen applicator is made of foam, cotton, other absorbent materials, or combinations thereof.

50. The method of any one of claims 41-49, wherein the targeted skin lesion is selected from the group consisting of a verruca (warts), lentigo (age spots), actinic keratoses (solar keratoses), seborrheic keratoses, achrochordon (skin tags), molluscum contagiosum, small keloids, dermatofibromas, keratocanthoma, granuloma annulare, angiomas, chondrodermatitis, epithelial nevus, porokeratosis plantaris discreta, leukoplakia, granuloma pyogenicum, pyogenic granuloma, and other topical skin lesions.

51. The method of any one of claims 41-49, wherein the at least one thermochromic material comprises at least one organic chemical.

52. The method of any one of claims 41-49, wherein the at least one thermochromic material comprises at least one inorganic material.

53. The method of any one of claims 41-49, wherein the cryogen gas in the container is a liquified cryogen gas.

54. The method of any one of claims 41-49, wherein the cryogen gas in the container is dispensed as an aerosol cryogen gas.

55. The method of claim 41 or claim 45, wherein the cryogen gas is selected from the group consisting of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and liquid nitrogen.

56. The method of claim 41 or claim 45, wherein the cryogen gas is a composition of one or more of dimethyl ether, propane, butane, R152A refrigerant, R410A refrigerant, R404A refrigerant, carbon dioxide, nitrous oxide, and/or liquid nitrogen.

57. A kit comprising the cryosurgical device of any one of claims 1, 16, or 22.

58. The kit of claim 57, wherein the cryosurgical device is partially or fully preassembled.

59. The kit of claim 57, wherein the cryosurgical device is disassembled.