1. Field of the Art
The present invention relates to devices and methods for cold plasma generation, and, more particularly, to such devices that are formed in the shape of a wand and methods for using same.
2. Background Art
At present, non-thermal (i.e., cold) atmospheric pressure plasmas for the treatment of biological substrates are found in two generalized forms. One form is the gas jet plasma, as exemplified by U.S. Provisional Application No. 60/913,369 and related matters (“the '369 family) and KinPen (PCT/EP2010/061166 application and related matters), which provide a jet of ions and reactive species that can be directed to a target over varying distances, specifically distances greater than a few millimeter. A second form is the Floating Electrode Dielectric Barrier Discharge (FE-DBD) devices, as known from the work of Fridman (PCT/US2010/027411 application), in which the target substrate (often the human body) acts as a floating ground electrode. By acting as the floating ground, the target directly attracts the electrical energy built up on the electrode until an arc, or plurality of arcs, is initiated. This arc generates ions in the atmosphere and drives those ions and reactive species to the target substrate. However, all conventional non-thermal DBD devices that utilize this floating electrode strategy are limited by the size of the area they can treat and the limited amount of variance allowed to the target treatment distance, generally less than 2 mm distance. When attempts are made to increase the size of the electrode, and thereby the surface area of treatment, or increase the distance from the target that an arc can be initiated, the heat generated by the electrode increases and can cause thermal destruction of sensitive substrates such as skin. These disadvantages are discussed further below.
Based on their electrode sizes required for non-thermal plasma output, typical FE-DBD devices can treat only a limited area at carefully controlled distances.
As mentioned above, the distance to the treatment area for FE-DBD devices must be carefully controlled for safety and to achieve a desired effect.
Other prior art cold plasma devices employ ring adapters (see, for example,
Referring to
What is needed is a DBD electrode design that can be easily manipulated over a plurality of surfaces while maintaining an ideal treatment distance as an inherent property of the electrode construction.
An embodiment is described of a cold plasma dielectric barrier discharge (DBD) device that is coupled to a power supply. The cold plasma DBD device has a wand-like shape. The wand-like shape can include a radius tip at the end of the wand-like device, and is round in cross-section, creating a tangential surface with a large number of distances between a relatively flat surface of a target substrate under treatment and the cold plasma DBD device. The length and diameter of the device can vary greatly depending on the desired size of the surface to be treated. Lengths of up to 1 meter with diameters of up to 40 mm have been constructed and successfully generate non-thermal plasma that is effective in surface modification and pathogen destruction. This longer, larger diameter device configuration effectively treats a much larger area and also allow for a greater variance in the target distance. This is achieved by creating a larger tangential surface treatment area, which helps maintain the optimal ˜2 mm or less target distance through the radius of curvature inherent to the wand design. This benefit also translates into the more effective treatment of complex biological and wound architecture based on the resulting optimal plasma distance exposure. In addition, no part of the device that is not generating plasma comes into direct contact with the treatment surface. This helps minimize potential contamination or surface irritation. Wands of this size are not generally possible with single frequency high voltage power supplies but are effectively powered by multi-frequency harmonic-rich power supplies as disclosed in the '369 family (see paragraph [0026] below).
A further embodiment is described of a method of producing cold plasma. The method includes receiving, from a power supply, electrical energy at a cold plasma dielectric barrier discharge (DBD) device. The cold plasma DBD device has a wand-like shape. The wand-like shape can include a radius tip at the end of the wand-like device, is round in cross-section, creating a large number of distances between a relatively flat surface of a target substrate under treatment and the cold plasma DBD device. The method also includes outputting the cold plasma at the target substrate over an effective area.
Cold temperature plasmas have attracted a great deal of enthusiasm and interest by virtue of their provision of plasmas at relatively low gas temperatures. The provision of plasmas at such a temperature is of interest to a variety of applications, including wound healing, anti-bacterial processes, treatments of musculoskeletal disorders, autoimmune disorder treatments and various other medical therapies and sterilization.
Embodiments of the present disclosure include cylindrical cold plasma DBD wand-like devices that provide a large cold plasma treatment area without the use of additional spatial control techniques. Powering these cylindrical cold plasma DBD devices with a multi-frequency harmonic-rich cold plasma (MFHCP) power supply avoids the formation of multiple discrete discharge points along the electrode (and associated pin-point heating and burning). The use of a MFHCP power supply results in a larger cold plasma treatment area (measured in centimeters or more) than that achievable (measured in millimeter values) with a single-frequency power supply. The dielectric of the DBD devices in embodiments of the present disclosure may be formed from polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyethylene (PE), polypropylene (PP), quartz, glass, or other dielectric materials known to one skilled in the art. The electrodes may be formed of a suitable metal or conductive gas separated from the target by the dielectric. Distribution of the energy can also be achieved by using a saline-filled DBD electrode, or a DBD electrode formed by metallic shavings (e.g., non-magnetic such as brass shavings) to improve the capacitance of the electrode and ensure cool discharge. The shapes of embodiments of the present disclosure are cylindrical, and may include a radiused tip. The larger variance in treatment distances available in embodiments of the present disclosure allows the inclusion of a handle for manual manipulation of the plasma. The use of a handle, or any form of manual manipulation, is not feasible with conventional DBD devices, as their plasma treatment distances must be precisely maintained and thereby be positioned with precision positioning equipment.
Embodiments described in the present disclosure can be directed to various medical treatment applications. In an exemplary embodiment, the cold plasma DBD wand device is powered by the multi-frequency harmonic-rich cold plasma (MFHCP) power supply (which generates a variety of harmonic frequencies simultaneously) and results in a cold plasma with a large treatment area (measured in centimeters or greater). As noted above, previous approaches would be unable to provide a large treatment area, as these prior approaches provided cold plasmas whose size was measured in millimeter values. The larger treatment areas available to embodiments described herein are useful for applications such as those described in U.S. application Ser. No. 14/026,679, entitled “Therapeutic Applications of Cold Plasma,” filed Sep. 13, 2013. The larger treatment areas available to embodiments described herein are also effective at treating various forms of musculoskeletal pain, fatigue, disorders and injuries. Musculoskeletal disorders (MSDs) can manifest in the upper or lower body. MSDs like fibromyalgia or work-related MSDs develop over time, affect the body's muscles, joints, tendons, ligaments, and nerves, and thereby greatly reduce a patient's quality of life. Due to the MFHCP devices' ability to reduce inflammation, deep tissue bruising can be cleared much more rapidly with the application of a MFHCP DBD device treatment protocol, thereby improving a patient's quality of life. In an embodiment, the MFHCP DBD wand device has been found to be effective in the treatment of tendonitis pain induced by repetitive stress. The MFHCP DBD wand device may also be effective at reducing spasticity in skeletal muscles caused by diseases affecting the central nervous system such as multiple sclerosis.
Still referring to embodiments of the present invention, the cold plasma DBD wand device's broad surface of plasma generation allows for the efficient treatment of larger areas with the benefits of being durable, portable, and being able to treat almost any anatomical structure. The terms “wand” and “wand device” are used to convey the notion that such a device is configured to deliver a cold plasma along a smooth peripheral area close to, and possibly including, its distal end, where the device is sufficiently small enough to negotiate placement at the desired treatment area without damaging either the treatment area, nearby regions or any regions encompassed during positioning of the wand device at the treatment area. Certain embodiments of the wand device may have a handle to enable negotiation of the wand device to the desired treatment area.
As noted above, embodiments of the present disclosure are cylindrical, receive high voltage internally, and have a dielectric barrier surrounding the inner, energized portion. In an embodiment, the MFHCP power source design (described in U.S. Provisional Patent Application No. 60/913,369, U.S. Non-provisional Application No. 12/038,159 (that has issued as U.S. Pat. No. 7,633,231) and the subsequent continuation applications (collectively “the '369 application family”), and the cold plasma high voltage power supply described in U.S. patent application Ser. No. 13/620,118 and U.S. Provisional Patent Application No. 61/535,250, which are incorporated herein by reference.) allows for a high level of ionization without substantial temperature rise due to its production of multiple frequencies. A further factor in the effective plasma delivery with a cold plasma DBD cylindrical device is the constant radius surface, which creates a tangential surface having an infinite number of discrete distances between the surface edge of the substrate under treatment and the wand device (see
Further details of three of the embodiments of the invention are provided below.
The electrical energy is passed from the external pins into the inner portion of the fluorescent light bulb, with the glass functioning as a dielectric barrier, such that plasma is generated on the external surface of the bulb when brought into contract with a ground or floating ground. The fluorescent bulb feature of the glass DBD wand still functions as a light source since high voltage is being applied to the internal gas and therefore the device may be designed to emit specific wavelengths radiation to thereby allow for enhanced levels of treatment. For example, if an ultraviolet light is emitted along with the plasma, enhanced disinfection may be achieved when the goal of a plasma therapy is antibiotic/antiseptic in nature. The generated UV can also be used to effectively treat skin disorders such as psoriasis and vitiligo. This embodiment simultaneously generates and combines reactive oxygen species (ROS), reactive nitrogen species (RNS), charged particles, together with the electroporation effects of cold plasma with UV light. The simultaneous generation and combination within the same device and in close proximity to the target greatly enhances antisepsis, or treatment modalities, that can be achieved.
The cold plasma DBD wand device generates cold plasma wherever it comes into direct or proximate contact with the target (when sufficient ground potential exists). In an exemplary embodiment, optimal treatment distances between the wand device and the treatment target range from direct physical contact up to ˜2 mm, depending upon the voltage, frequency, substrate conductance, substrate capacitance, and the dielectric properties of the medium through which the plasma passes. It should be stressed that with a large diameter cylindrical electrode, such as the fluorescent light bulb, even when the surface is brought into direct contact with the substrate, there are discharge points along the entire radius of curvature at varying distances from the substrate. This is not the case with a planar electrode where the entire electrode is substantially the same distance from, or in direct contact with, the target substrate.
In a second embodiment, a standard ⅜ inch copper plumbing pipe is cut to size and a heavy-duty heat shrink wrap is added to the outer surface of the copper tubing to act as the dielectric barrier. Several advantages to the copper pipe DBD wand device are that it is less fragile, very inexpensive to manufacture, it cannot release toxic materials Hg) if broken, and any length and diameter can be selected. The “copper” based embodiments may be fanned in a number of different ways. An advantage of using a “copper pipe” embodiment over an alternative “solid copper rod” embodiment is a significant reduction in manufacturing costs and weight, particularly for large wand devices. Due to the use of MFHCP power source, MFHCP DBD wand devices are markedly larger in diameter and length than any of those previously developed, thereby creating a considerably more generous surface area for treatment.
Further details of embodiments of the present invention can be found by reference to the following figures.
The same core cold plasma DBD device may be employed with a carrier in an industrial process setting. For example, the same core cold plasma DBD device may be employed in a food processing setting, as further explained in U.S. patent application Ser. No. 14/103,540, filed Dec. 11, 2013, which is incorporated herein by reference in its entirety. When the core cold plasma DBD device is used in a setting where manual manipulation is used (e.g., clinician setting), a handle is typically attached. Thus, from a terminology point of view, the term “wand” is used herein to denote the attachment of a handle such that manual manipulation of the cold plasma device may be accomplished.
The process begins at step 1210. In step 1210, electrical energy is received at a cylindrical cold plasma DBD device. In an embodiment, cylindrical cold plasma device 800 receives the electrical energy.
In step 1220, cold plasma is output at a target substrate from the cylindrical cold plasma DBD device, wherein the diameter of the electrode is in excess of 1 centimeter.
At step 1230, method 1200 ends.
The above disclosure provides various embodiments of cylindrical cold plasma
DBD devices that provide a large cold plasma treatment area. In the context of this application, a large cold plasma treatment area refers to the need to project a cold plasma to a target treatment area using a cold plasma DBD electrode having a diameter in excess of 1 centimeter, something that has not been achievable by prior approaches. The ability to project over such distances by cylindrical cold plasma DBD devices is enabled by the use of a multi-frequency harmonic-rich cold plasma (MFHCP) power supply. Such a supply avoids the formation of multiple discrete discharge points along the electrode (and associated pin-point heating and burning). Consequently, the use of a MFHCP power supply results in a larger cold plasma treatment area (measured in centimeters or more) than that achievable with a single-frequency power supply. Distribution of the cold plasma energy can also be achieved by using a saline-filled DBD electrode, or by using a DBD electrode formed by metallic shavings (e.g., non-magnetic such as brass shavings). The dielectric of the DBD devices in embodiments of the present disclosure may be formed from polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyethylene (PE), polypropylene (PP), quartz, glass, or other dielectric materials known to one skilled in the art. The shapes of embodiments of the present disclosure are cylindrical, and may include a radiused tip.
As discussed above, the larger electrode diameters available in embodiments of the present disclosure allows for the inclusion of a handle for manual manipulation of the plasma. The use of a handle, or any form of manual manipulation, is not feasible with conventional DBD devices, as they must be positioned with precision positioning equipment. Thus, the cylindrical cold plasma DBD device may be passed over the treatment area or substrate, or the cylindrical cold plasma DBD device may be stationary with the substrate moving in proximity to the cylindrical cold plasma DBD device.
It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present invention as contemplated by the inventor(s), and thus, are not intended to limit the present invention and the appended claims in any way.
The present invention has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.
The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.
The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
This application claims the benefit of U.S. Provisional Application No. 61/747,828, filed Dec. 31, 2012 and entitled “Method and Apparatus for Dielectric Barrier Discharge Wand Cold Plasma Device,” which is incorporated herein by reference in its entirety. This application is related to U.S. Provisional Application No. 60/913,369, filed Apr. 23, 2007; U.S. patent application Ser. No. 12/038,159, filed Feb. 27, 2008 (which issued as U.S. Pat. No. 7,633,231); U.S. patent application Ser. No. 13/620,118, filed Sep. 14, 2012, and U.S. patent application Ser. No. 14/103,540, filed Dec. 11, 2013, each of which are herein incorporated by reference in their entireties.
Number | Date | Country | |
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61747828 | Dec 2012 | US |