Abstract:
A material and method delivering to the skin therapeutic radiation and filtering a part of the sun spectrum causing skin damage.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to a protective material, a clothing item and methods of protection and therapy and especially, but not exclusively, to use of special materials for manufacturing clothes which can effectively convert incident radiation in the form of sunlight to light comprising substantially wavelengths having dermatological therapeutic effect and in which wavelengths having deleterious effect are reduced, compared to sunlight.  
       BACKGROUND OF THE INVENTION  
       [0002]     Various light sources have been proposed for therapy of different dermatological problems. For example, blue light in the range of 400-420 nm has been found helpful for acne treatment. U.S. Pat. No. 6,835,202 describes a device for acne treatment having spectrum 405-440 nm. Red light at 590 nm and 632 nm is used for skin rejuvenation and U.S. Pat. No. 6,676,655 describes a method of skin treatment using devices emitting light in narrowband multichromatic spectrum having the wavelengths corresponding to tissue absorption peaks. U.S. Pat. No. 6,645,230 describes devices for photodynamic therapy using specific light spectrum ranges.  
         [0003]     Although some wavelengths of the electromagnetic spectrum have strong therapeutic effect, the full broad spectrum of sunlight, (which includes ultraviolet, visible and infrared ranges) is known to have deleterious effects on the skin. For example, exposure to direct sunlight is a major reason for skin damage and premature aging, and (particularly the ultraviolet component) can cause skin cancer.  
       SUMMARY OF THE INVENTION  
       [0004]     According to a first aspect of the present invention a material is provided having the following optical properties:  
         [0005]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage; and  
         [0006]     transmission of a substantial amount of the electromagnetic radiation in sunlight that has therapeutic effect for the human skin.  
         [0007]     According to a second aspect of the present invention there is provided a material having the following optical properties:  
         [0008]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage; and  
         [0009]     converting at least part of the absorbed radiation to radiation having therapeutic effect on human skin.  
         [0010]     According to a third aspect of the present invention there is provided a material having the following optical properties:  
         [0011]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage; transmission of at least a part of the electromagnetic radiation in sunlight that has a therapeutic effect on human skin; and  
         [0012]     converting at least part of the absorbed radiation to radiation that has a therapeutic effect on human skin.  
         [0013]     Preferably, said optical properties of the material are at least partially resultant from the material having been dyed with one or more pigments. Such a material could be in the form of a continuous non-porous sheet of material.  
         [0014]     Preferably, said material is a fabric.  
         [0015]     Preferably, said fabric is made from polymer fiber dyed with one or more pigments.  
         [0016]     One or more pigments may be a fluorescent agent.  
         [0017]     Said radiation that has a therapeutic effect on human skin can include wavelengths absorbed by porphyrin.  
         [0018]     Said radiation that has a therapeutic effect on human skin preferably has wavelengths greater than about 400 nm.  
         [0019]     Said radiation that has a therapeutic effect on human skin can include wavelengths in the range of 400-490 nm.  
         [0020]     Said radiation that has a therapeutic effect on human skin can include wavelengths stimulating collagen growth.  
         [0021]     Said radiation that has a therapeutic effect on human skin can include wavelengths from 590 nm to 670 nm.  
         [0022]     Preferably at least some of said radiation that causes skin damage has a wavelength less than about 400 mm.  
         [0023]     Preferably at least some of the electromagnetic radiation in sunlight that causes skin damage which is absorbed by the material is ultra-violet radiation.  
         [0024]     Preferably, the material prevents transmission therethrough of at least 50% of said radiation that causes damage in human skin.  
         [0025]     Preferably the material prevents transmission therethrough of at least 75% of said radiation that causes damage in human skin.  
         [0026]     Preferably the material prevents transmission therethrough of at least 90% of said radiation that causes damage in human skin.  
         [0027]     Preferably the material prevents transmission therethrough of at least 98% of said radiation that causes damage in human skin.  
         [0028]     Preferably the material allows transmission therethrough of at least 50% of a specific wavelength or selection of wavelengths of radiation in sunlight that have a therapeutic effect on human skin.  
         [0029]     Preferably the material allows transmission of at least 70% of said one or more selected therapeutic wavelengths.  
         [0030]     Preferably the material allows transmission of at least 90% of said one or more selected therapeutic wavelengths.  
         [0031]     It will be appreciated that the above percentages relate to percentages of incident radiation (of the type specified), under normal conditions, with the angle of incidence of the radiation to the material being approximately 90 degrees.  
         [0032]     The material may comprise a first layer and a second layer with different optical properties.  
         [0033]     The first layer may include a fluorescent agent for emitting therapeutic radiation.  
         [0034]     The second layer may have a filtration function to filter out a substantial amount of radiation that causes skin damage.  
         [0035]     According to a fourth aspect of the present invention there is provided a portable item which includes at least a portion made from a material in accordance with at least one of the first to third aspects, such that in use, when being carried or worn by a wearer, in sunlight, the item of clothing can protect at least an area of the wearer&#39;s skin from electromagnetic radiation in sunlight that causes skin damage, while allowing radiation that has a therapeutic effect on human skin to be transmitted from said material to said area of the wearer&#39;s skin.  
         [0036]     The item can be an item of clothing.  
         [0037]     The material is preferably in accordance with at least one of the first second and third aspects.  
         [0038]     According to a fifth aspect of the present invention there is provided a method for protection of the skin from electromagnetic radiation in sunlight that causes skin damage, comprising:  
         [0039]     delivering some of the electromagnetic radiation from sunlight to the skin, through a material having the following optical properties:  
         [0040]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage; and  
         [0041]     transmission of a substantial amount of electromagnetic radiation in sunlight that has therapeutic effect for the human skin;  
         [0042]     and thereby allowing exposure of the skin to electromagnetic radiation from sunlight that has therapeutic effect for human skin.  
         [0043]     According to a sixth aspect of the present invention there is provided a method for protection of the skin from electromagnetic radiation in sunlight that causes skin damage, comprising:  
         [0044]     preventing delivery of at least some of the electromagnetic radiation in sunlight to the skin, by providing a barrier to sunlight, said barrier being at least partially formed by a material having the following optical properties:  
         [0045]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage;  
         [0046]     converting at least part of the absorbed radiation to radiation having therapeutic effect on human skin;  
         [0047]     and thereby allowing exposure of the skin to electromagnetic radiation that has therapeutic effect for human skin.  
         [0048]     According to a seventh aspect of the present invention there is provided a method for protection of the skin from electromagnetic radiation in sunlight that causes skin damage, comprising:  
         [0049]     delivering some of the electromagnetic radiation from sunlight to the skin, through a material having the following optical properties:  
         [0050]     absorption of at least a substantial proportion of the electromagnetic radiation in sunlight that causes skin damage; and  
         [0051]     transmission of a substantial amount of electromagnetic radiation in sunlight that has therapeutic effect for the human skin;  
         [0052]     converting at least part of the absorbed radiation to radiation having therapeutic effect on human skin;  
         [0053]     and thereby allowing exposure of the skin to electromagnetic radiation that has a therapeutic effect for human skin.  
         [0054]     The method may be used for skin therapy.  
         [0055]     A topical agent can be applied to the skin surface prior the light delivery.  
         [0056]     The topical agent may be a precursor of photosensitizer.  
         [0057]     According to one embodiment of the invention the fabric includes natural fibres, such as cotton, (and) or a mix of natural fibres with manmade fibres.  
         [0058]     It will be appreciated that the optional or preferable features recited above will be applicable to various aspects of the invention.  
         [0059]     It will be appreciated that the phrase “therapeutic effect for human skin” is to be construed broadly: for example radiation that destroys bacteria, but which has no significant other therapeutic or harmful effect on human skin should be considered to fall within the meaning of this phrase. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0060]     Embodiments of the invention will hereafter be described, by way of example only, with reference to the accompanying drawings, in which:  
         [0061]      FIG. 1  is a schematic cross sectional view of a piece of material in accordance with an embodiment of the present invention, with incident and transmitted electromagnetic radiation illustrated schematically thereon;  
         [0062]      FIG. 2  is a schematic cross sectional view of a piece of material in accordance with an alternative embodiment of the present invention, with incident, emitted and transmitted electromagnetic radiation illustrated schematically thereon;  
         [0063]      FIG. 3  is a schematic illustration of an item of clothing, in the form of a baseball cap in accordance with an embodiment of the present invention, in use; and  
         [0064]      FIG. 4  is a schematic cross sectional exploded view of a piece of material in accordance with an alternative embodiment of the present invention, with incident, emitted and transmitted electromagnetic radiation illustrated schematically thereon. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0065]     With reference to  FIG. 1 , in one embodiment a material, designated  100 , is shown schematically, with a larger arrow  105  illustrating full spectrum sunlight incident upon the material  100 , and a smaller arrow  110  illustrating a lesser amount of radiation which has been transmitted through the material, the remainder having been effectively filtered by the material.  
         [0066]     Importantly, certain wavelengths which exist in sunlight are known to be harmful to the skin, and the optical properties of the material  100  are such that a substantial amount of the harmful radiation is filtered out. Certain wavelengths which exist in sunlight are known to have therapeutic effect for certain skin conditions, and the optical properties of the material  100  are such that a substantial amount of the therapeutic radiation is transmitted.  
         [0067]     In one embodiment the material  100  is a fabric which transmits only a relatively small proportion of the incident sunlight  105 , and transmits substantially only parts of the spectrum which have a therapeutic effect. Such a fabric can be used for shirts, hats and other clothes. The material may transmit radiation in one or more spectral bands.  
         [0068]     With reference to  FIG. 2 , in a second embodiment a material, designated  200 , is shown schematically. In this embodiment some of the radiation of the incident sunlight is transmitted, some is absorbed by the material  200 , and some of the absorbed radiation is re-emitted at one or more wavelengths which have a therapeutic effect. As illustrated in  FIG. 2 , a larger arrow  205  illustrates full spectrum sunlight incident upon the material  200 , a first smaller arrow  210  illustrates a smaller amount of radiation which has been transmitted through the material  200  and a second smaller arrow  220  illustrates an amount of radiation which has been re-emitted by the material  200 .  
         [0069]     As with the first embodiment  100 , the material  200  can be a fabric can be used for shirts, hats and other clothes. The material  200  may transmit and/or emit radiation in one or more spectral bands.  
         [0070]     It will be appreciated that a further (third) embodiment comprises a material in which substantially no sunlight is simply transmitted through the material, but in which some therapeutic radiation is emitted from the side of the material opposite to the side upon which the sunlight is incident. A schematic illustration of such an embodiment would effectively be the same as the illustration of  FIG. 2 , but with the first smaller arrow,  210 , omitted. Such an embodiment will not, therefore, be explicitly illustrated in a separate drawing.  
         [0071]     With reference to  FIG. 3 , an embodiment of an item of clothing in the form of a baseball cap  300 , has a brim  301  formed from a material in accordance with the embodiment of  FIG. 2  (that is, by the second embodiment, although it will be appreciated that variations could be provided by use of the first or third of the three embodiments described above). Sunlight, illustrated by arrow  305 , incident upon the brim  301 , has a substantial amount of the harmful radiation filtered from it, and by a combination of transmission and re-emission results in radiation  310 , which includes a substantial therapeutic component (and a reduced harmful component compared to sunlight) being incident upon the face of a wearer  320  of the baseball cap  300 .  
         [0072]     It will be appreciated that use of a material, such as is described in relation to the above general descriptions of three embodiments, to shield a subject from at least some of the harmful radiation in sunlight (or other electromagnetic radiation having a harmful component) so that therapeutic radiation is transmitted and/or emitted, so that it can reach a subject, might correspond to a method of protecting a subject from the harmful radiation, and a method of therapy. A particularly convenient form of such a method is to use clothing made from such a material, and to use sunlight as the light source. Of course, alternatives are possible: for example, a parasol or umbrella made from the material could provide a similar effect.  
         [0073]     In one embodiment the optical properties of the material allow transmission and/or emission of wavelengths in the range 400-420 nm. Exposure of the skin of a subject to these wavelengths may provide a useful acne treatment. Radiation in this range of wavelengths interacts with porphyrin generated by bacteria, and this photodynamic reaction destroys the bacteria, reducing the acne. Of course, such an embodiment does not preclude transmission and/or emission of a broader range of wavelengths, such as 400-440 nm, or 400-490 nm and some embodiments target these wavelengths. In some embodiments, other wavelengths which may be suitable for treatment of acne can additionally or alternatively be targeted, such as wavelengths in the range 630-670 nm. Light can interact with porphyrins produced by human cells. The effect can be amplified by applying topical cream with photosensitizing properties. Such a cream may include some precursors of porphyrins or other photosensitizing agents. Application of an appropriate substance, which in one embodiment can be a topical cream, may improve the efficacy of a method of skin treatment such as those described above. The method can include the use of one or more photosensitizing agents. In a variation, photosensitizing agents may be utilized in ways other than being applied to the skin: for example orally or intravenously administered photosensitizing agents could be used.  
         [0074]     Of course, wavelengths with therapeutic effect on conditions other than acne could be utilized. Wavelengths in the orange and red part of the visible spectrum are known to stimulate collagen growth and to have skin rejuvenation effect. Interaction of light in this spectral range with fibroblast stimulates its growth.  
         [0075]     In preferred embodiments the material is a fabric, facilitating manufacture of comfortable clothing items from (or incorporating) such a material. In manufacture of a fabric having the desired optical properties, the following synthetics are examples of polymer materials which can conveniently be used: acetate; acrylic; nylon; latex; polyester; rayon. Of course, other materials could be used and, in particular, materials made from natural fibres, such as cotton, or a mix of natural fibres with manmade fibres, can be used.  
         [0076]     Fluorescent or filtering dye can be impregnated into the polymer. There is a large number of laser and fluorescent dyes which provide light emission in the visible and near infrared spectrum, and from which dyes suitable for emitting desired therapeutic wavelengths can be selected for use in a material.  
         [0077]     In one embodiment, in order to deliver therapeutic radiation to the skin of a subject while protecting the skin of the subject from harmful radiation the fabric should:  
         [0078]     be substantially transparent (and/or translucent) to the desired therapeutic radiation;  
         [0079]     absorb a substantial proportion of the harmful radiation part of sunlight; and  
         [0080]     convert at least some non-desired parts of the sunlight into the desired therapeutic radiation.  
         [0081]     In some embodiments, concentration of the dye in the fabric should be high enough to absorb most of the harmful radiation (but see also the description below, of the embodiment of  FIG. 4 ).  
         [0082]     By way of example, the following dyes can be used for transforming ultraviolet (UV) radiation into blue light: DAPI; Hoechst 334. These dyes are known per se and sometimes used in fluorescent spectroscopy.  
         [0083]     Thus, for example, polyester fabric impregnated with DAPI dye can be used to protect the skin from UV radiation and enhance delivery of blue light in the range 400 nm-450 nm and should therefore provide therapeutic effect for acne.  
         [0084]     The fluorescent dye known as Cy3 dye, has an excitation spectrum in the range of 470-570 nm and a fluorescence (emission) spectrum in the red spectrum 550-650 nm. Broadly speaking this dye may be considered to ‘shift’ the wavelength of incident radiation from a shorter wavelength to a longer wavelength. This dye can be imbedded into a polymer for manufacture of a fabric that can be used to stimulate fibroblast.  
         [0085]     For example, a synthetic fabric, such as that sold under the trademark CoolDry, could be manufactured in a form dyed with Cy3 dye to deliver to the skin the red radiation. It will be appreciated that in this example conversion of at least part of the absorbed radiation to radiation that has a therapeutic effect on human skin is certainly occurring even though the absorbed radiation utilized for ‘conversion’ to therapeutic radiation is not considered particularly harmful.  
         [0086]     In one embodiment a combination of a several dyes can be used to provide better protection from harmful radiation, and/or to provide exposure of the skin of the subject to more, or a greater range of, therapeutic radiation.  
         [0087]     Additionally, or alternatively, a material in accordance with the present invention, may comprise more than one layer, with different layers having different optical properties, but so that the material as a whole has the desired optical properties. For example, as illustrated in  FIG. 4  in schematic, exploded form, a material generally designated  400 , has a first, florescent, layer  402  and a second, filtration, layer  404 . The first, fluorescent, layer  402 , includes a dye which absorbs harmful radiation and emits therapeutic radiation. The second, filtration, layer  404  is substantially transparent to the therapeutic radiation but substantially opaque to harmful radiation.  FIG. 4  illustrates schematically a situation where a considerable amount of incident harmful radiation  406  and a relatively small amount of incident therapeutic radiation  408  are incident upon the first layer  402 . The first, fluorescent, layer  402  absorbs a certain amount of harmful radiation and both transmits and emits therapeutic radiation, so that a reduced amount of harmful radiation  416  and an enhanced amount of therapeutic radiation  418  reach the second, filtration, layer  404 . The second, filtration, layer  404  filters out the remaining harmful radiation, so that substantially no harmful radiation passes through the material  400 , but so that substantially all of the enhanced amount of therapeutic radiation  418  exits the material. It will be appreciated that  FIG. 4  is an exploded view and that in practical embodiments the layers  402 ,  404  would usually be in contact with each other. It should also be appreciated that the representation of the radiation is schematic, and that the incident harmful and therapeutic radiation would be likely to be components of the spectrum of sunlight. In one embodiment the second, filtration, layer  404  can be a coating applied to a first, fluorescent, layer  402  which is in the form of a fabric. The coating could comprise nano particles of inorganic substance such as a suitable metal oxide, such as zinc oxide, which have been found to be effective in filtering ultra-violet radiation while allowing transmission of visible light.  
         [0088]     It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or in any other country.  
         [0089]     In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.  
         [0090]     Variations and modifications can be made in respect of the invention described above and defined in the following statement of claim.