Plasma Jet Device

Abstract

The present invention relates to a low-temperature atmospheric pressure plasma jet device (3) comprising at least one capillary tube (20) including at least one noble gas supply inlet (22), a plasma generation region (24), and at least one plasma outlet (26), wherein the capillary tube includes a section (60) having an enlarged cross section downstream of the plasma generation region and upstream of a distal portion of the capillary tube, preferably the section having an enlarged cross section with a width-to-height ratio between 0.1 and 1000, the width corresponding to the maximum internal diameter of the section having the enlarged cross section.

Description

[Technical Field]

[0001] The present invention relates to a low-temperature atmospheric pressure plasma jet device, in particular to the field of low-temperature plasma used in cosmetic or medical applications, especially in skin applications such as the treatment of cancer cells, scarring or disinfection of wounds, e.g. chronic or acute post-operative wounds, or in the context of transplants, to promote scarring and prevent infection after transplant surgery, or for preparing the skin before transplantation. [Background technology]

[0002] The use of low-temperature plasma generated from noble gases, usually helium or argon, at room temperature, subjected to an electrical discharge delivered by a high-voltage power supply is well known in the field of skin medical applications. This plasma propagates in a pulsed, sometimes periodic manner, to the outlet of the capillary tube, where, upon contact with the surrounding air, it generates active oxygen and nitrogen species which, together with the electric field, produce the biological effects of the low-temperature plasma.

[0003] Treatment of skin with low-temperature atmospheric pressure plasma technology has proven beneficial in the treatment of skin wounds, itching, and skin infections. In particular, plasma is known to accelerate wound scar formation by reducing inflammation through activation of the body's defense mechanisms and recruitment of immune cells to the wound area, activating fibroblasts that induce rearrangement of the actin cytoskeleton to promote matrix synthesis, activating scar-forming cytokines and growth factors in fibroblasts and keratinocytes, and inducing angiogenesis and the production of pro-angiogenic proteins in vascular endothelial cells, thereby promoting re-epithelialization.

[0004] The use of cold plasma has the advantage that no direct contact is required and it does not cause any pain to the patient. In addition, the treatment time is relatively short and no allergic reactions, bacterial resistance or other side effects have been observed so far.

[0005] Furthermore, numerous studies have shown that bacteria, fungi, biofilms, viruses and spores can be killed very effectively by cold plasma (biocidal action).

[0006] However, currently available European standard plasma generating devices do not allow for control of the plasma dose and power applied to a given area of ​​skin. In addition, these devices do not allow for variation of the area of ​​plasma application. In particular, currently known devices only allow the practitioner to control the length of plasma application, due to the uneven distribution of delivered power and plasma. Applying treatment primarily based on length criteria creates significant uncertainty, resulting in non-reproducible treatments.

[0007] Patent Document 1 discloses an atmospheric pressure plasma generator having a plasma generation region with an increased volume to enable treatment of a large area, and the plasma generation region is made of an insulating material to stabilize plasma formation throughout the plasma generation region. Patent Document 1 specifies that the plasma generation region can be made of sintered ceramic, which is a material that is sufficiently resistant to withstand the plasma thus generated.

[0008] Patent document 2 describes a plasma generator for generating a larger volume of plasma, where the discharge behind the generation of the plasma is stable.

[0009] Patent document 3 describes, inter alia, a plasma processing device including an electrode formed from a conductive layer covered with an insulating substrate, the substrate being made of sintered ceramic. The device described in Patent document 3 makes it possible to obtain a plasma processing device at lower cost and more resistant to discharge instabilities.

[0010] US Pat. No. 5,629,999 describes an electrode device for plasma discharge that allows for improved energy efficiency. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 8,961,888 [Patent Document 2] U.S. Patent Application Publication No. 2011 / 0042008 [Patent Document 3] U.S. Patent Application Publication No. 2010 / 0147464 [Patent Document 4] U.S. Patent Application Publication No. 2009 / 0016941 Summary of the Invention [Problem to be solved by the invention]

[0012] There is a great need for a device to facilitate cold plasma treatment of all kinds of wounds, in particular a device that will ensure the reproducibility of skin treatment and make it possible to adapt the treatment to each type of wound, especially for wounds with large areas, and a device that will make it possible to minimize the length of cold plasma treatment and ensure its safety.

[0013] The present invention aims to meet all or some of these needs. [Means for solving the problem]

[0014] Plasma Diffuser According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising: at least one capillary tube including at least one noble gas supply inlet, a plasma generation region, and at least one plasma outlet; at least one plasma diffuser arranged on the outlet path of the capillary tube, arranged so that the plasma generated in the plasma generation region passes through the plasma diffuser, the plasma diffuser being made of a porous material, the median pore size of which is advantageously between 0.1 μm and 5 mm, better still greater than 1 μm and less than 1 mm, and even better still greater than 10 μm and less than 500 μm; The present invention relates to a low-temperature atmospheric pressure plasma jet device including:

[0015] The device according to the invention allows for uniform distribution of plasma, and also allows for easy treatment of large wound areas and reduced application times.

[0016] In particular, the presence of a plasma diffuser on the capillary exit path increases the distance from 1 to 50 cm. 2 This allows for uniform treatment of areas in the range of 1000 to 1500 nm with a single plasma pulse. Specifically, the presence of a plasma diffuser at the exit of the capillary tube can allow for a 1000-fold increase in the area to which the generated plasma can be applied compared to devices that do not include any diffusion elements.

[0017] Finally, the use of the device according to the invention makes it possible to reduce the consumption of noble gases, in particular making it possible to advantageously limit losses during the ejection of plasma from the device.

[0018] By capillary tube is meant the tube through which the cold plasma jet is generated and propagates.

[0019] The plasma diffuser facilitates increasing the cross-sectional area of ​​the plasma jet.

[0020] The median pore size of the plasma diffuser may be greater than 0.1 μm and less than 5 mm, better greater than 1 μm and less than 1 mm, better greater than 10 μm and less than 500 μm, better greater than 40 μm and less than 100 μm, and better greater than 50 μm and less than 80 μm.

[0021] The plasma diffuser may have a thickness between 100 μm and 5 cm, better still between 500 μm and 1 cm, and even better still between 800 μm and 0.5 cm.

[0022] The thickness of the plasma diffuser may be variable.

[0023] Preferably, the thickness of the plasma diffuser remains constant.

[0024] The plasma diffuser can be made of a dielectric, a semiconductor, a metal, or a metal coated with a dielectric, or a combination of these materials, and preferably the plasma diffuser is made of a dielectric.

[0025] In one embodiment of the present invention, the plasma diffuser is made of sintered ceramic, preferably sintered glass containing a high dielectric constant material such as alumina or perovskite.

[0026] The plasma diffuser may be in a plane perpendicular to the direction of propagation of the plasma within the capillary tube.

[0027] In one embodiment, multiple plasma diffusers are positioned on the outlet path of the capillary tube such that the plasma generated in the plasma generation region passes through the plasma diffusers in sequence.

[0028] The capillary tube may include a distal portion including the plasma outlet that is flared. The flared distal portion may extend over a length in the direction of plasma propagation of 20 cm or less, preferably 10 cm or less, and even better 5 cm or less. The ratio of the maximum diameter of the distal portion to the minimum diameter of the distal portion may be between 1 and 100.

[0029] These diameters are measured perpendicular to the direction of plasma propagation and are internal diameters, i.e. the walls of the tube are not taken into account when measuring them.

[0030] Preferably, the plasma diffuser is positioned in the flared distal portion of the capillary, perpendicular to the direction of propagation of the plasma within the capillary.

[0031] A plasma diffuser positioned in this manner allows for a larger plasma size to be stabilized, and also prevents back-diffusion of air into the flared distal section, thus improving the stability and uniformity of the plasma passing through the diffuser.

[0032] The plasma diffuser may be located at the end of the flared distal portion, or in other words, the plasma diffuser may be located at the distal portion of the capillary tube having the largest diameter.

[0033] The capillary tube may include a wall of constant or variable thickness. In the special case of a wall of variable thickness, the wall of the distal portion may be wider than the wall of the plasma generation region. The wall of the distal portion may have a thickness ranging between 0.1 mm and 5 mm. The ratio of the wall thickness of the plasma generation region to the thickness of the distal portion may be between 0.1 and 10.

[0034] The device according to the invention may comprise more than two plasma outlets and / or more than two capillaries. Preferably, the number of plasma outlets is between 1 and 100, preferably between 1 and 50, and even better between 1 and 10.

[0035] In one embodiment of the present invention, the apparatus includes a capillary tube that includes three plasma outlets, each of which includes a plasma diffuser.

[0036] In a preferred embodiment of the invention, the apparatus comprises a plurality of capillaries, each capillary comprising three plasma outlets, each of the plasma outlets comprising one plasma diffuser, and each capillary preferably comprising one noble gas supply inlet.

[0037] A plasma diffuser can be disposed on the exit path of each plasma outlet, the plasma device includes the same number of plasma diffusers as the number of plasma outlets, or plasma diffusers can be disposed on the exit paths of multiple plasma outlets.

[0038] According to another variant of the invention, a number of successive plasma diffusers can be arranged on the exit path of each plasma outlet.

[0039] The plasma diffuser can be raised to a predetermined potential, or preferably, the plasma diffuser can be at a floating potential or connected to active or passive electrodes to allow modulation of the plasma propagation.

[0040] Buffer Volume According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising: at least one capillary tube including at least one noble gas supply inlet, a plasma generation region, and at least one plasma outlet; The low-temperature atmospheric pressure plasma jet device includes: The capillary includes an enlarged cross-section downstream of the plasma generation region and upstream of the distal portion of the capillary, the enlarged cross-section preferably having a width / height ratio between 0.1 and 1000, preferably between 0.5 and 100, better still between 0.8 and 10, the width corresponding to the maximum inner diameter of the enlarged cross-section.

[0041] The width corresponds to the maximum internal diameter of the expanded cross section, this diameter being measured perpendicular to the direction of propagation of the plasma within the tube, this diameter being referred to as the internal diameter, i.e. the wall of the tube is not taken into account.

[0042] The expanded cross-section creates a buffer volume that allows the plasma ignition voltage, i.e., the voltage that must be applied to the electrodes to be able to form a plasma in the plasma generation region of the capillary, to be reduced by approximately 20%. This reduces the energy required for plasma propagation. In addition, the generated electromagnetic noise is reduced.

[0043] The cross-sectional enlargement advantageously opens onto the bottleneck in the direction of the plasma outlet.

[0044] Furthermore, such an enlarged cross-section allows for better control of the plasma dose, i.e., the amount of plasma energy delivered from the device, and therefore the application of the plasma to the area to be treated.

[0045] The device may include sensors that measure the pressure in the enlarged cross-section and / or the propagation speed of the plasma in the capillary.

[0046] The enlarged cross-section section may be positioned at a distance between 0 cm and 10 cm, preferably between 0 cm and 7 cm, more preferably between 0 cm and 5 cm from the plasma outlet.

[0047] The diameter of the enlarged cross section may be variable, in particular increasing and then decreasing from upstream to downstream.

[0048] The internal volume of the cross-sectional expansion can have a shape adapted to the gas flow, i.e. substantially spherical, better spherical, substantially elliptical, better elliptical, substantially cylindrical, better cylindrical, or substantially parallelepiped, better parallelepiped.

[0049] Of course, this list is not limiting: the interior volume of the enlarged cross-section can have other geometric shapes, in particular shapes that may or may not have an axis or center of symmetry, and may also be combinations of the aforementioned shapes.

[0050] The internal volume of the expanded cross-section is 0.2 cm 3 and 250cm 3 Between, preferably 0.5 cm 3 and 200cm 3 Between, better 1cm 3 and 25cm 3 It can be between.

[0051] The minimum diameter of the capillary tube may be the diameter of the bottleneck, i.e., the diameter of the outlet of the cross-sectional expansion in the direction of plasma propagation.

[0052] Preferably, the diameter of the entrance of the enlarged cross section is greater than the diameter of the bottleneck.

[0053] The bottleneck can be raised to a predetermined potential, the predetermined potential being selected to keep the cold plasma at the expanding cross-section, and the predetermined potential being changed to allow the cold plasma to move towards the plasma outlet.

[0054] In one particular embodiment, the capillary includes a plurality of plasma outlets, and the enlarged cross-sectional area includes a plurality of bottlenecks, each leading to one of the plasma outlets.

[0055] Alternatively, the capillary includes a plurality of plasma outlets, with one enlarged cross-section provided within the capillary for each plasma outlet.

[0056] The ratio of the maximum diameter of the enlarged cross section to the diameter of the feed inlet and / or the maximum diameter of the enlarged cross section to the diameter of the bottleneck may be between 1 and 1000, preferably between 1 and 500, and better still between 1 and 50.

[0057] The ratio of the maximum diameter of the enlarged cross section to the minimum diameter of the capillary may be between 2 and 40.

[0058] In one particular embodiment, the distal portion is flared. The capillary tube can have a cross-sectional area with a minimum diameter between the enlarged cross-sectional area and the flared distal portion.

[0059] Alternatively, the diameter of the distal portion of the capillary remains constant.

[0060] The enlarged cross-sectional area may have a wall of less thickness than the wall of the distal portion.

[0061] The ratio of the wall thickness of the distal portion to the wall thickness of the enlarged cross-section may be between 1 and 4.

[0062] The enlarged cross-section portion may be made of a different material to the capillary tube, but preferably is made of the same material as the capillary tube and is integrally formed therewith.

[0063] The capillary tube, including the at least one noble gas supply inlet, the at least one plasma outlet, the plasma generation region and the cross-sectional enlargement, can be manufactured by molding or blow molding, or even by additive manufacturing.

[0064] The capillary tube, including the at least one noble gas supply inlet, the at least one plasma outlet, the plasma generation region and the cross-sectional enlargement, can be made of glass or any insulating material with a high dielectric constant.

[0065] The capillary tube, including the at least one noble gas supply inlet, the at least one plasma outlet, the plasma generation region and the cross-sectional enlargement, may be monolithic.

[0066] The maximum diameter of the capillaries is preferably less than 3 mm, more preferably less than 1 mm.

[0067] The capillary tube may be partially detachable, in particular the distal portion, preferably the portion downstream of the plasma generation region is detachable, i.e. can be disengaged / unscrewed from the portion containing the plasma generation region and the noble gas supply inlet.

[0068] The removable downstream portion and the upstream portion including the plasma generation region and the noble gas supply inlet can have complementary shapes. In particular, the upstream portion can have a shape that is complementary to a plurality of different removable downstream portions.

[0069] ignition The device according to the invention may comprise a high voltage electrode fixed to the outer and / or inner wall of the capillary, the electrode being configured to deliver a first electric signal and a second electric signal having two different frequencies, the frequency of the first electric signal being defined such that when the electrode delivers the first electric signal, a rare gas introduced into the capillary and subjected to the voltage of the first electric signal generates a plasma, the frequency of the second electric signal being defined such that a pulse is generated which induces propagation of the plasma towards the plasma outlet, the frequency of the second electric signal being lower than the frequency of the first electric signal, and the ratio between the first signal frequency and the second signal frequency is preferably greater than 1 and less than or equal to 1000, more preferably between 3 and 100, and even better between 5 and 50.

[0070] The second signal advantageously induces and / or accelerates the propagation of the plasma within the capillary.

[0071] The second signal makes it possible in particular to adapt the plasma dose emitted by the device.

[0072] Plasma dose refers to the amount of plasma energy delivered to the target.

[0073] In one embodiment of the present invention, the first electrical signal is a carrier wave modulated by the second signal. Such an embodiment advantageously allows for a substantial reduction in electromagnetic noise generated by the plasma jet device.

[0074] In another embodiment, the first and second electrical signals are delivered via a first electrode and a second electrode, respectively, the first electrode being positioned upstream of the second electrode in the direction of plasma propagation.

[0075] The second electrode may be disposed downstream of the cross-sectional expansion in the direction of plasma propagation.

[0076] A second electrode can be positioned in a distal portion of the capillary.

[0077] In one particular embodiment, the device may comprise at least two second electrodes, for example, located in the bottleneck of the device according to the invention, including the cross-sectional enlargement, and in the distal part of the capillary.

[0078] The first and / or second electrodes may be located on the outside or inside of the wall of the device.

[0079] The device can include a switch that, when closed, emits a second electrical signal, and thus, can deliver the second electrical signal only when the switch is open, e.g., when a pushbutton is pressed.

[0080] The first signal may be a DC, AC, pulsed or hybrid signal.

[0081] The second signal can be a DC, AC or pulsed signal.

[0082] Advantageously, the device according to the invention allows for better control of the plasma dose output from the device.

[0083] Parameter Control A device according to the invention may include one or more sensors selected from, for example, a voltage sensor, a power sensor, a frequency sensor, a flow sensor, a distance sensor or a thermal sensor.

[0084] The sensor may be configured to measure the power of the plasma output from the plasma diffuser and / or output from the plasma generator.

[0085] The sensor may be configured to measure a voltage between the plasma output from the plasma diffuser and an area to which the plasma is intended to be applied, or between the plasma output from the plasma generator and an area to which the plasma is intended to be applied.

[0086] The sensor may be configured to measure the temperature during application of the low temperature plasma to the area to which the plasma is intended to be applied.

[0087] Preferably, the device according to the present invention further comprises a control module configured to analyze measurements produced by the one or more sensors.

[0088] The control module may be configured to modify, in response to the analyzed measurements produced by the one or more sensors, the voltage or frequency of the electrical signal delivered for the purpose of generating plasma in the plasma generation region, the voltage or frequency of the electrical signal delivered for the purpose of inducing or accelerating the propagation of plasma in the capillary, the plasma dose emitted by the device onto the target corresponding to the region to which the plasma is intended to be applied, the temperature of the plasma at the plasma outlet of the capillary, the pressure in the plasma generation region, the noble gas pressure in the capillary, the pressure in the cross-sectional expansion section, the noble gas flow rate at the supply inlet.

[0089] In one embodiment, the control module displays the measurements and / or an analysis of the measurements on a digital interface, and the operator can then easily modify the frequency, voltage, pressure, and / or flow rate to match the desired plasma dose output from the device and / or to select a particular plasma regime.

[0090] Low-temperature plasmas exist in various regimes, and their discharges can be of different types (diffused jet discharge, filament discharge, hollow cathode discharge) depending on the generation conditions.

[0091] Mode of plasma regime refers to the mode of operation of the plasma that allows for a particular type of discharge to be achieved.

[0092] The device according to the invention advantageously allows real-time adaptation of the delivered plasma dose, facilitating application and ensuring safety of the treatment.

[0093] Preferably, the device according to the invention comprises a plurality of capillaries, a control module and a sensor, and optionally a digital interface, the device preferably being configured such that the capillaries are controlled independently of each other.

[0094] How to use According to another of its aspects, the present invention relates to the use of a porous material comprising pores with a median diameter between 0.1 μm and 5 mm as a plasma diffuser, preferably in a low-temperature plasma jet device.

[0095] The porous material may contain pores with a median diameter between 1 μm and 1 mm, better between 10 μm and 500 μm, even better between 40 μm and 100 μm, and even better between 50 μm and 80 μm.

[0096] The porous material may have a thickness between 100 μm and 5 cm.

[0097] The porous material may be of variable thickness, but preferably has a constant thickness.

[0098] The porous material can be made of a dielectric, a semiconductor, a metal, or a metal covered with a dielectric, and preferably the porous material is made of a dielectric.

[0099] Preferably the porous material is made of a sintered ceramic, preferably a sintered glass containing a high dielectric constant material such as alumina or perovskite.

[0100] The porous material according to the invention can be used as a plasma diffuser for all fields of application using low temperature plasma, in particular for applications involving surface treatment or grafting or adhesive bonding or propulsion.

[0101] Preferably, the invention relates to the use of a porous material according to the invention as a plasma diffuser in an apparatus for medical applications.

[0102] The various aspects of the invention can be combined with one another. In particular, the device according to the invention can include a plasma diffuser and a cross-sectional expansion.

[0103] The terms "upstream", "downstream", "inlet" and "outlet" are defined relative to the direction of propagation of the noble gas and of the plasma. The terms "inside" and "outside" and "inside" and "outside" are defined relative to the location of the plasma relative to the device, the plasma being inside the device.

[0104] The invention will perhaps be better understood on reading the following detailed description of non-limiting examples of its implementations and on examining the accompanying drawings, in which: [Brief explanation of the drawings]

[0105] [Figure 1] FIG. 1 is a schematic diagram showing a longitudinal section of a plasma generating device illustrating the generation of low-temperature plasma. [Figure 2] 1 is a schematic diagram showing a longitudinal section of a plasma jet device including a plasma diffuser according to the present invention; [Figure 3] 1 shows a longitudinal cross section of a plasma jet device including a plasma diffuser according to the present invention; [Figure 4a] 1A-1D illustrate various embodiments of an apparatus including a plasma diffuser according to the present invention. [Figure 4b] 1A-1D illustrate various embodiments of an apparatus including a plasma diffuser according to the present invention. [Figure 4c] 1A-1D illustrate various embodiments of an apparatus including a plasma diffuser according to the present invention. [Figure 4d] 1A-1D illustrate various embodiments of an apparatus including a plasma diffuser according to the present invention. [Figure 4e] 1A-1D illustrate various embodiments of an apparatus including a plasma diffuser according to the present invention. [Figure 5] FIG. 1 is a diagram illustrating the application of plasma to an area by a plasma jet device. [Figure 6]6 is a graph showing the propagation and distribution of plasma by the device according to FIG. 5; [Figure 7] 1 shows, inter alia, a plasma jet device including an enlarged cross-sectional area. [Figure 8] 1 shows a plasma jet device including an enlarged cross-sectional area according to the present invention; [Figure 9] 1 is a schematic diagram showing a perspective view from below of an apparatus including a cross-sectional enlargement according to the present invention; [Figure 10] 1 is an example of an apparatus according to the present invention including a cross-sectional enlargement and a plasma diffuser. DETAILED DESCRIPTION OF THE INVENTION

[0106] In the remainder of the description, elements that are identical or have identical functions are given the same reference numerals. These descriptions will not be repeated for each of the figures, but will only note the main differences between the embodiments.

[0107] FIG. 1 shows the operation of a prior art plasma jet device 1.

[0108] Conventionally, cold plasma is generated in a dielectric tube 10 containing a noble gas 12 at room temperature, and an electrode 14 fixed to the dielectric tube 10 generates an electromagnetic field. Cold plasma 16 is generated as a result of the noble gas 12 being exposed to the electromagnetic field. A cold plasma jet 16 is emitted from the device 1.

[0109] FIG. 2 shows diagrammatically a longitudinal cross-sectional view of a plasma jet device 2 according to the invention, including a plasma diffuser 28 .

[0110] The apparatus 2 includes, inter alia, a capillary tube 20 including at least one noble gas supply inlet 22 for supplying noble gas 12, a plasma generation region 24, at least one plasma outlet 26, and a plasma diffuser 28 arranged on the outlet path of the capillary tube, the plasma diffuser 28 being arranged so that the plasma 16 generated in the plasma generation region 24 passes through the plasma diffuser 28, the plasma diffuser being made of a porous material whose median pore size is between 0.1 μm and 5 mm, preferably between 1 μm and 1 mm, and better still between 10 μm and 0.5 μm.

[0111] Upon exiting the tube, the plasma 16 propagates uniformly over a large application area.

[0112] The noble gas 12 can be helium, argon, neon, or a mixture of gases, such as argon and 5% oxygen. Preferably, the noble gas is helium.

[0113] The flow rate of the noble gas may be between 0.2 and 5 L / min, preferably about 1 L / min.

[0114] At least one high voltage electrode 14 is fixed to the outer wall of the capillary tube and enables plasma to be generated in a plasma generation region 24 from a noble gas 12 introduced through a feed inlet 22 .

[0115] The electrodes are capable of delivering a sinusoidal electrical signal at a frequency between 50 Hz and 100 kHz, preferably about 10 kHz, and at a voltage between 1 kV and 30 kV, preferably between 2 kV and 4 kV.

[0116] A second electrode 30 may be fixed to the wall of the capillary tube 20 downstream of the first electrode 14 in the direction of plasma propagation.

[0117] The second electrode may be a low voltage or a high voltage electrode. Preferably, the second electrode is a low voltage electrode, thus limiting the electromagnetic noise generated by the device 2.

[0118] The second electrode advantageously induces or accelerates the propagation of the cold plasma 16 by capillary action within the capillary tube 20 .

[0119] The second electrode can be controlled by a control module (not shown).

[0120] In particular, the control module can be configured to allow a user to tailor the plasma dose output from the device by controlling the voltage delivered by one or more electrodes. For example, the control module can be configured such that when a switch is closed, voltage is delivered through the second electrode, and when the switch is open, no voltage is delivered through the second electrode.

[0121] In one particular embodiment of the present invention, a single electrode 14 delivers the first and second electrical signals via a modulated signal including, for example, a carrier wave at frequency f and a lower frequency signal, the frequency of which is the lowest frequency signal.

[0122] The high frequency carrier generates the low temperature plasma, and the low frequency signal induces the propagation and / or accelerated propagation of the low temperature plasma.

[0123] The electrode(s) 14, 30 are preferably positioned against the outer surface of the capillary wall, and the plasma thus generated is isolated from the electrode(s) by the thickness of the capillary wall, allowing it to come into contact with the living body without risk of electric shock or overheating.

[0124] The porous material 28 may include pores whose median diameter is between 1 μm and 5 mm.

[0125] thickness of porous material e 28 can be between 100 μm and 5 cm.

[0126] thickness of porous material e 28 may be variable. Preferably, the thickness of the porous material e 28 remains constant.

[0127] Figure 3 shows another embodiment of the device 2 according to the invention. This device differs from the example shown in Figure 2 in that it includes, inter alia, a flared distal portion 20a in which a plasma diffuser 28 is arranged. The combination of the flared distal portion according to the invention and a plasma diffuser made of a porous material makes it possible to significantly increase the application area of ​​the cold plasma output from the device.

[0128] The plasma diffuser 28 may be located at the distal end of the capillary tube, for example as shown in Figures 4a, 4c and 4d.

[0129] Alternatively, as shown in Figure 4b, the plasma diffuser 28 can be located inside the capillary, not necessarily at its periphery, but at a distal portion of the capillary. In particular, the plasma diffuser 28 can be located at a distance d of 10 mm or less. 28,26 may separate the plasma outlet 26 from the porous material 28 .

[0130] An apparatus according to the present invention may include multiple noble gas supply inlets 22, possibly multiple plasma generation regions 24, and a plasma outlet 28. One such example is shown in Figure 4c.

[0131] An apparatus according to the present invention may include multiple plasma outlets 26, with one plasma diffuser 28 positioned on the path of each capillary outlet 26, as shown in Figure 4d.

[0132] The number of plasma outlets 26 is not limited to 1 or 2. The device according to the invention may include more than two plasma outlets, in particular the capillary tube 20 may include three plasma outlets. Preferably, the number of plasma outlets is between 1 and 100.

[0133] The device according to the invention can accommodate a modular, removable and replaceable plasma outlet or plasma head. In particular, the plasma outlet can be mechanically fixed to the capillary tube.

[0134] A device according to the invention may include multiple capillaries 20, as shown in Figure 4e.

[0135] A device according to the present invention comprising multiple capillaries 20 may include capillaries that differ from one another. The capillaries 20 may differ from one another in the number of their feed inlets 22, the number of their plasma outlets 26, the presence of one or more plasma diffusers 28, the presence of an enlarged cross-sectional area 60, the maximum or minimum diameter of the capillary, the thickness of the capillary wall, or the presence of a flared distal portion 20a. This list is not limiting.

[0136] FIG. 6 is a graph showing the propagation of plasma in a capillary tube 20 containing a porous material 28' on the plasma exit path.

[0137] The results shown in the graph were obtained by experiment using the apparatus shown in Figure 5, where the porous material 28' contains pores with median diameters between 40 and 100 µm.

[0138] During the experiment, a plasma was generated in a capillary tube 20 exposed to an electromagnetic field by a ring-shaped high-voltage copper electrode 14, the plasma was applied to a glass target area 4 with an aluminum strip deposited underneath, a space of 5 mm separating the plasma outlet 26 of the capillary from the target area 4, and the electrode 14 generated an electrical signal at a frequency of 15 kHz and a voltage of approximately 4.4 ± 0.30 kV.

[0139] The x and y axes of the graph in Figure 6 represent pixel numbers, with 1 pixel equal to 50 μm.

[0140] In the graph, it is possible to see, in particular, a first stage 51 in which the plasma propagates along the capillary tube 20, a second stage 52 in which the plasma reaches and passes through the porous material 28', and finally a third stage 53 in which the plasma is applied across the porous material 28' to the surface 4.

[0141] It can be seen that the plasma distribution is uniform and the plasma spreads over a relatively large area.

[0142] FIG. 7 shows a plasma jet device 3 according to the invention including an enlarged cross-sectional area 60 .

[0143] The apparatus 3 shown in Figure 7 includes a capillary tube 20 including a noble gas supply inlet 22, a plasma generation region where plasma is generated by an electrode 14, and a plasma outlet 26, the capillary tube including an enlarged cross-sectional section 60 downstream of the plasma generation region and upstream of a distal portion 20a of the capillary tube.

[0144] In one embodiment, the expanded cross-sectional area 60 can include the plasma generation region 24 .

[0145] Ratio D of the maximum diameter of the cross-sectional expansion portion 60 to the height p,max / h p can be between 0.1 and 100.

[0146] The enlarged cross section advantageously opens onto the bottleneck 62 in the direction of the plasma outlet 26 .

[0147] The enlarged cross-section section 60 may be located at a distance D from the plasma exit between 0 cm and 10 cm.

[0148] Diameter of the expanded cross section d p may be variable, in particular increasing and then decreasing from upstream to downstream. In one embodiment, the diameter d p may decrease from upstream to downstream.

[0149] The interior volume of the enlarged cross-section can have a shape that is substantially spherical, better spherical, substantially elliptical, better elliptical, or substantially cylindrical, better cylindrical. These examples are non-limiting.

[0150] The internal volume of the expanded cross-section is 0.2 cm 3 and 250cm 3It can be between.

[0151] The minimum diameter of the capillary is the diameter of the bottleneck d s It can be said that:

[0152] In one particular embodiment, the capillary includes multiple plasma outlets and the enlarged cross-section includes multiple bottlenecks 62, each leading to one plasma outlet. An example of such an embodiment is shown in Figure 9, which shows a view from below of a capillary 20 including three plasma outlets 26 and one enlarged cross-section 60.

[0153] Alternatively, one enlarged cross section is provided in the capillary for each plasma outlet.

[0154] Maximum diameter of the cross-sectional expansion section Entrance diameter d of the cross-sectional expansion section e may be between 1 and 1000, preferably between 1 and 500, and better still between 1 and 50.

[0155] Diameter d of the bottleneck of the maximum diameter of the cross-sectional expansion section s may be between 1 and 1000, preferably between 1 and 100, and better still between 1 and 50.

[0156] Preferably, the diameter d of the inlet of the cross-sectional expansion section e is the diameter of the bottleneck d s Greater than.

[0157] This advantageously allows for an increased propagation speed of the plasma in the distal portion of the capillary via the Venturi effect.

[0158] The diameter of the distal portion 20a of the capillary may remain constant, as shown in FIG.

[0159] In one particular embodiment, the distal portion 20a is flared.

[0160] As shown in the example of Figure 8, the expanded cross-section section has a wall thickness of the distal part e s Smaller thickness e p The wall may have a thickness of 100 mm.

[0161] Distal wall thickness e s The wall thickness of the expanded cross section e p Ratio to e s / e p can be between 1 and 4.

[0162] The maximum diameter of the capillary is less than 3 mm, preferably less than 1 mm.

[0163] The device according to the invention may include sensors 641, 642, in particular a light sensor 641, a heat sensor or a voltage sensor 642.

[0164] The sensors 641, 642 can deliver measurements through a feedback mechanism to a control module 66 which can adapt the plasma dose delivered from the device, preferably by adapting the treatment time, the power (via the voltage and / or frequency delivered by the high voltage power supply 70 to the electrode 14 used to generate the plasma), the power (via the voltage and / or frequency delivered by the high voltage power supply to another electrode fixed to the wall of the capillary, preferably to the outer wall, preferably downstream of the electrode used to generate the plasma, this electrode being configured, for example, to induce or accelerate the propagation of the plasma towards the plasma outlet), and / or the flow rate of the noble gas at the noble gas supply inlet 22.

[0165] The sensor may include a voltage sensor that measures the voltage difference along the capillary tube.

[0166] The sensor may include a voltage sensor 642 that measures the difference in voltage between the capillary and the area 4 to which the plasma is intended to be applied.

[0167] The sensor may include a temperature sensor that measures the temperature at the plasma outlet or in the region 4 where the plasma is intended to be applied.

[0168] The sensor may include a flow sensor that measures the flow rate of the noble gas entering the supply inlet.

[0169] Sensors can include biosensors, ie, sensors capable of detecting and converting a biochemical signal into a quantifiable physical signal.

[0170] The sensor may for example comprise an electrocardiogram fixed to the area 4 to which the plasma is intended to be applied.

[0171] The control module 66 can vary one or more parameters selected from the treatment time, the power, voltage, and / or frequency delivered by the high voltage power supply 70 to the electrodes fixed to the capillary wall, preferably the outer wall, and / or the flow rate of the noble gas at the noble gas supply inlet 22, making it possible to adapt the plasma dose emitted from the device.

[0172] In one particular embodiment of the present invention, rather than adapting the plasma dose emitted from the device through a feedback mechanism, the control module 66 transmits measurements delivered by the sensor or an analysis of the measurements delivered by the sensor to the control interface 68 via digital communication means 72.

[0173] The control interface 68 allows the user to manually control the plasma dose emitted from the device and adapt it according to measurements delivered by the sensors 641,642.

[0174] In particular, the user can vary the power, voltage and / or frequency delivered by the high voltage power supply 70 to the electrode 14 used to generate the plasma, the power, voltage and / or frequency delivered by the current source to another electrode fixed to the wall of the capillary, preferably the outer wall, preferably downstream of the electrode used to generate the plasma, for example, an electrode configured to induce or accelerate the propagation of the plasma towards the plasma outlet, and / or the flow rate of the noble gas at the noble gas supply inlet 22, and / or the distance from the plasma outlet 26 to the region 4 to which the plasma is intended to be applied.

[0175] FIG. 10 shows an example of an implementation of the device according to the invention, including a plasma diffuser 28 and a cross-sectional enlargement 60 .

[0176] Example A comparison of four plasma jet devices was carried out.

[0177] This comparison made it possible to measure the maximum area over which the plasma could be spread uniformly through the plasma jet when the plasma was generated and applied by one of four devices: KinPen® MED (Neoplas GmbH, Greifswald, Germany), PlasmaDerm® (CINOGY GmbH, Duderstadt, Germany), SteriPlas (Adtec Plasma Technology, Adtec Europe, Hounslow, UK), and a device according to the invention including a plasma diffuser.

[0178] The KinPen® MED is a handheld device containing a pen-shaped applicator that possesses a continuously generated medical plasma source and delivers a low-temperature atmospheric-pressure plasma jet using argon as a carrier gas. Typical plasma plume lengths are 8 to 12 mm and 1 mm in diameter. The plasma jet is guided vertically over the target with precise and arbitrary three-dimensional motion of approximately 5 mm / s, leading to an average treatment time of 30 to 60 seconds / cm2. The KinPen® MED therefore delivers a focused, non-dispersing jet. The effective treatment area is several mm2. 2 is reduced to

[0179] PlasmaDerm® is a plasma device that allows for the treatment of large areas. 27cm 2 It is equipped with multiple configurable plasma heads that allow for the coverage of areas up to 10 ...

[0180] The SteriPlas is a large, caster-mounted medical device with an articulating arm equipped with a treatment head that emits a cold, argon-based plasma toward the treatment area. The plasma torch has six electrodes, and argon is used as a carrier gas to transport the gas stream to the target. The plasma torch opening has a diameter of 3.5 cm and a 12 cm 2 Treatment area up to

[0181] The device according to the first aspect of the invention allows the initial propagation of a single plasma jet from 1 to 50 cm, without the need for contact with a target. 2 It becomes possible to cover an area of

[0182] As is now clearly apparent, the device according to the invention allows for better propagation of the plasma. Not only can larger areas be treated more quickly and more uniformly, but the device also allows for better adaptability and greater dosing accuracy. Such a device is particularly advantageous for treating burns, for example in patients with severe burns. In general, such a device is suitable for treating all kinds of wounds, in particular different types of chronic wounds.

[0183] It was not obvious that sintered glass in particular could be used as a porous material in a plasma diffuser in a low-temperature plasma jet device. In particular, although the use of sintered glass in plasma jet devices is well known in the prior art due to its mechanical properties (such as its resistance to corrosion, abrasion, compression, high temperatures and chemicals) that enable it to withstand the conditions of plasma generation, it has not previously been envisaged for use as a diffuser operated by a plasma jet.

[0184] The present invention allows for dynamic control of the plasma dose emitted from the plasma jet device, thus allowing the user to better tailor each treatment to the wound or clinical situation.

[0185] Of course, the invention is not limited to the example embodiments that have been described here.

[0186] In particular, the device according to the invention may include a safety system configured to control the plasma dose emitted from the device, and / or to control the delivered electrical current, and / or to control the temperature of the plasma output from the device, and / or to control the power of the plasma, and / or to control the noble gas pressure in a noble gas cylinder supplying the noble gas supply inlet of the capillary, and / or, when the capillary includes a cross-sectional enlargement, to control the noble gas pressure in the capillary, particularly in the cross-sectional enlargement. For example, the safety system may be a high-speed circuit breaker or a microcontroller controlling the high-voltage power supply of the electrodes used to generate the plasma.

[0187] The device according to the present invention is preferably designed with redundancy, particularly to comply with medical device regulations.

[0188] In particular, the device according to the invention is preferably configured to comply with all or some of the following standards: ISO 13485:2016, ISO 14971:2019, IEC 62304 / A1:2018, IEC 62366-1:2015, ISO 15223-1:2016, ISO 10993, IEC 60601-1, AAMI TIR 57, 14155:2020 (for RIPH1), DIN SPEC 91315. This list is not exhaustive.

[0189] The expressions "comprising a" and "comprising one" should be understood to be synonymous with "including at least one." [Explanation of symbols]

[0190] 1. Plasma jet device 2. Plasma jet device 3. Plasma jet device 4 Target area 10 Dielectric tube 12 Noble Gases 14 First electrode 16. Plasma 20 Capillary 20a Flared distal portion 22 Noble gas supply inlet 24 Plasma generation region 26 Plasma outlet 28 Plasma Diffuser 28′ porous material 30 Second electrode 60 Enlarged cross section 62 Bottleneck 641 optical sensor 642 voltage sensor 66 Control Module 68 Control Interface 70 High voltage power supply 72 Digital Communication Methods

Claims

1. A low-temperature atmospheric pressure plasma jet device (3) comprising at least one capillary tube (20) having at least one noble gas supply inlet (22), a plasma generation region (24) and at least one plasma outlet (26), A low-temperature atmospheric pressure plasma jet device (3), wherein the capillary tube is provided with an enlarged cross-section (60) downstream of the plasma generation region and upstream of the distal portion of the capillary tube.

2. 2. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the enlarged cross-sectional area is disposed at a distance between 0 cm and 10 cm, preferably between 0 cm and 7 cm, more preferably between 0 cm and 5 cm from the plasma outlet.

3. 3. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1 or 2, wherein the diameter of the cross-sectional expansion section is variable, in particular increasing and then decreasing from upstream to downstream.

4. 4. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the internal volume of the enlarged cross-section has a shape that is substantially spherical, better spherical, substantially elliptical, better elliptical, substantially cylindrical, better cylindrical, or substantially parallelepiped, better parallelepiped.

5. The internal volume of the enlarged cross-sectional area is 0.2 cm ３ and 250 cm ３ and preferably between 0.5 cm ３ and 200 cm ３ and better still between 1 cm ３ and 25 cm ３ The low-temperature atmospheric pressure plasma jet device according to claim 4, wherein

6. 6. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the minimum diameter of the capillary is the diameter of a bottleneck portion where the cross-sectional enlargement portion opens.

7. 7. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein a diameter of the inlet of the enlarged cross-section portion is larger than a diameter of a bottleneck portion into which the enlarged cross-section portion opens.

8. The low-temperature atmospheric pressure plasma jet device according to claim 1 , wherein a bottleneck portion where the cross-sectional enlarged portion opens rises to a predetermined potential.

9. 9. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the capillary includes a plurality of plasma outlets, and the enlarged cross-sectional portion opens into a plurality of bottleneck portions each leading to one plasma outlet.

10. 9. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the capillary includes a plurality of plasma outlets, and one enlarged cross-sectional area is provided in the capillary for each of the plasma outlets.

11. 11. The low-temperature atmospheric pressure plasma jet apparatus according to claim 1, wherein the cross-sectional expansion has a width / height ratio between 0.1 and 1000, and the width corresponds to a maximum inner diameter of the cross-sectional expansion.

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