Plasma jet device

Abstract

The invention relates to a cold atmospheric pressure plasma jet device (3) comprising:-at least one capillary tube (20) comprising at least one inert gas supply inlet (22), a plasma generation zone (24) and at least one plasma outlet (26); the capillary includes a cross-sectional enlarged portion (60) downstream of the plasma generation zone and upstream of a distal portion of the capillary, preferably the cross-sectional enlarged portion has a width-to-height ratio of between 0.1 and 1000, the width corresponding to a maximum inner diameter of the cross-sectional enlarged portion.

Description

Technical Field

[0001] The present invention relates to cold atmospheric pressure plasma jet devices. In particular, the present invention relates to devices for cosmetic or medical applications, particularly in the field of cold plasma, for skin applications, such as the treatment of cancer cells, the healing or disinfection of wounds (e.g., chronic or acute postoperative wounds), or in the context of transplantation, to promote healing and prevent infection after transplantation or to prepare the skin before transplantation. Background Art

[0002] In the field of dermatological applications, the use of cold plasma generated by an inert gas (usually helium or argon) subjected to a discharge from a high-voltage power supply at room temperature is well known. The plasma propagates to the outlet of the capillary in a pulsed and possibly periodic manner and, upon contact with the ambient air, produces reactive oxygen and nitrogen species that, together with the electric field, contribute to the biological effects of the cold plasma.

[0003] Treating the skin with cold atmospheric pressure plasma technology has been shown to be beneficial in the treatment of skin wounds, itching, and skin infections. In particular, plasma is known to accelerate wound healing by promoting re-epithelialization and re-epithelialization, reducing inflammation by activating the body's protective mechanisms and mobilizing immune cells to the wound area, activating fibroblasts that induce actin cytoskeleton rearrangement and promote matrix synthesis, activating scar cytokines and growth factors in fibroblasts and keratinocytes, and inducing angiogenesis and the production of pro-angiogenic proteins in endothelial cells.

[0004] The advantages of using cold plasma are that it does not require direct contact and is painless to the patient. Furthermore, treatment time is relatively short, and no allergic reactions, bacterial resistance, or other side effects have been observed to date.

[0005] Furthermore, numerous studies have shown that bacteria, fungi, biofilms, viruses and spores can be killed very effectively with the help of cold plasma (bactericidal activity).

[0006] However, the European standard plasma-generating devices currently on the market do not allow for control over the plasma dose and power applied to a given skin area. Furthermore, these devices do not allow for modification of the plasma application area. Specifically, currently known devices only allow the practitioner to control the duration of plasma application, as the delivered power and distribution of the plasma are non-uniform. Application of treatments based primarily on duration criteria can lead to significant uncertainty and non-reproducibility of treatments.

[0007] US Pat. No. 8,961,888 discloses an atmospheric pressure plasma generator having a plasma generation region of increased volume to allow for treatment of a larger area, the plasma generation region being made of an insulating material to stabilize plasma formation throughout the plasma generation region. US Pat. No. 8,961,888 provides that the plasma generation region may be made of a sintered ceramic having sufficient resistance to withstand the plasma generated thereby.

[0008] US 2011 / 0042008 describes a plasma generator for generating a larger volume of plasma, wherein the discharge after the generation of the plasma is stabilized.

[0009] US 2010 / 0147464 describes a plasma treatment device comprising, among other things, an electrode formed of a conductive layer covered by an insulating substrate made of sintered ceramic. The device described in US 2010 / 0147464 makes it possible to obtain a plasma treatment device that is more resistant to discharge instabilities at a lower cost.

[0010] US 2009 / 0016941 describes an electrode arrangement for a plasma discharge which allows an increase in energy efficiency. Summary of the Invention

[0011] There is a real need for a device that facilitates cold plasma treatment of any type of wound. In particular, there is a need for a device that ensures reproducibility of skin treatment and allows the treatment to be adapted to each type of wound, especially wounds of large areas. There is also a real need for a device that allows the duration of cold plasma treatment to be minimized while ensuring its safety.

[0012] The present invention is directed to satisfying all or some of these needs.

[0013] Plasma diffuser

[0014] According to a first aspect of the present invention, the present invention relates to a cold atmospheric pressure plasma jet apparatus comprising:

[0015] - at least one capillary comprising at least one inert gas supply inlet, a plasma generation region and at least one plasma outlet;

[0016] - at least one plasma diffuser placed on the outlet path of the capillary, said plasma diffuser being positioned so that the plasma generated in said plasma generation zone passes through said plasma diffuser, said plasma diffuser being made of a porous material, the median pore size of the porous material being advantageously between 0.1 μm and 5 mm, better still greater than 1 μm and less than 1 mm, even better still greater than 10 μm and less than 500 μm.

[0017] The device according to the invention allows for a uniform spread of the plasma. It also allows for easy treatment of wounds over large areas and reduces application time.

[0018] In particular, the presence of a plasma diffuser on the exit path of the capillary allows for uniform treatment of 1-50 cm² in a single plasma pulse. 2 In particular, the presence of the plasma diffuser at the outlet of the capillary makes it possible to multiply the area over which the generated plasma is applicable by a factor of 1000 compared to a device that does not include any diffuser element.

[0019] Finally, the use of the device according to the invention makes it possible to have a lower consumption of inert gas. In particular, such a device advantageously makes it possible to limit the losses during the ejection of the plasma from the device.

[0020] A capillary is a tube in which a cold plasma jet is generated and propagated.

[0021] The plasma diffuser facilitates an increase in the cross section of the plasma jet.

[0022] The median pore size of the plasma diffuser may be greater than 0.1 μm and less than 5 mm, more preferably greater than 1 μm and less than 1 mm, more preferably greater than 10 μm and less than 500 μm, more preferably greater than 40 μm and less than 100 μm, and more preferably greater than 50 μm and less than 80 μm.

[0023] The plasma diffuser may have a thickness between 100 μm and 5 cm, better still between 500 μm and 1 cm, even better still between 800 μm and 0.5 cm.

[0024] The thickness of the plasma diffuser may be variable.

[0025] Preferably, the thickness of the plasma diffuser remains constant.

[0026] The plasma diffuser may be made of a dielectric, a semiconductor, a metal, or a metal covered with a dielectric, or a combination of these materials. The plasma diffuser is preferably made of a dielectric.

[0027] In one embodiment of the present invention, the plasma diffuser is made of sintered ceramic, preferably sintered glass including, for example, a high-k material such as alumina or perovskite.

[0028] The plasma diffuser may be located in a plane perpendicular to the direction of plasma propagation in the capillary.

[0029] In one embodiment, a plurality of plasma diffusers are placed on the exit path of the capillary tube and are positioned such that the plasma generated in the plasma generation region passes through the plasma diffusers continuously.

[0030] The capillary tube may include a distal portion including a flared plasma outlet. The flared distal portion may extend in the direction of plasma propagation for a length of less than or equal to 20 cm, preferably less than or equal to 10 cm, and more preferably less than or equal to 5 cm. The ratio of the maximum diameter of the distal portion to the minimum diameter of the distal portion may be 1 to 100.

[0031] These diameters are measured perpendicular to the direction of propagation of the plasma and are internal diameters, ie they are measured without taking the tube wall into account.

[0032] Preferably, the plasma diffuser is positioned in the flared distal portion of the capillary tube perpendicular to the direction of propagation of the plasma in the capillary tube.

[0033] Such positioning of the plasma diffuser allows for stabilization of larger plasma sizes.In addition, the plasma diffuser prevents air from diffusing back into the flared distal end portion, thereby improving the stability and uniformity of the plasma passing through the diffuser.

[0034] The plasma diffuser may be positioned at the end of the flared distal portion, or in other words, the plasma diffuser may be positioned at the distal portion of the capillary tube having the largest diameter.

[0035] The capillary tube may include a wall of fixed or variable thickness. In the specific case where the wall thickness is variable, 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 between 0.1 mm and 5 mm. The ratio of the thickness of the wall of the plasma generation region to the thickness of the distal portion may be between 0.1 and 10.

[0036] 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, more preferably between 1 and 50, more preferably between 1 and 10.

[0037] In one embodiment of the present invention, the apparatus comprises a capillary tube comprising three plasma outlets, each plasma outlet comprising a plasma diffuser.

[0038] In a preferred embodiment of the present invention, the device comprises a plurality of capillaries, each capillary comprises three plasma outlets, each plasma outlet comprises a plasma diffuser, and each capillary preferably comprises an inert gas supply inlet.

[0039] A plasma diffuser may be positioned on the outlet path of each plasma outlet, the plasma apparatus comprising as many plasma diffusers as plasma outlets. Alternatively, a plasma diffuser may be positioned on the outlet path of a plurality of plasma outlets.

[0040] According to another variant of the invention, a plurality of consecutive plasma diffusers can be positioned on the exit path of each plasma outlet.

[0041] The plasma diffuser may be raised to a predetermined potential.Preferably, the plasma diffuser may be at a floating potential or connected to an active or passive electrode so that the propagation of the plasma may be modulated.

[0042] Buffer volume

[0043] According to a second aspect of the present invention, the present invention relates to a cold atmospheric pressure plasma jet apparatus comprising:

[0044] - at least one capillary comprising at least one inert gas supply inlet, a plasma generation region and at least one plasma outlet;

[0045] The capillary comprises a cross-sectional expansion section downstream of the plasma generation zone and upstream of the distal end portion of the capillary, the cross-sectional expansion section preferably having a width / height ratio between 0.1 and 1000, preferably between 0.5 and 100, more preferably between 0.8 and 10, the width corresponding to the maximum inner diameter of the cross-sectional expansion section.

[0046] The width corresponds to the maximum inner diameter of the cross-sectional enlargement, said diameter being measured perpendicular to the direction of propagation of the plasma in the tube. Said diameter is referred to as the inner diameter, ie without taking into account the tube wall.

[0047] The expanded cross-sectional area forms a buffer volume, allowing the plasma ignition voltage—that is, the voltage required to form a plasma in the plasma generation region of the capillary—to be reduced by approximately 20%. Consequently, less energy is required to propagate the plasma. Furthermore, the generated electromagnetic noise is reduced.

[0048] The cross-sectional expansion advantageously opens into the bottleneck in the direction of the plasma outlet.

[0049] Furthermore, the section with enlarged cross-section allows for better control of the plasma dose, ie the amount of plasma energy transferred out of the device, and thus the application of the plasma to the area to be treated.

[0050] The apparatus may comprise a sensor for measuring the pressure in the section of enlarged cross section and / or the propagation speed of the plasma in the capillary.

[0051] The cross-section-enlarged section may be located at a distance from the plasma outlet of between 0 cm and 10 cm, preferably between 0 cm and 7 cm, and more preferably between 0 cm and 5 cm.

[0052] The diameter of the section with an enlarged cross section may be variable, in particular it may first increase and then decrease from upstream to downstream.

[0053] The internal volume of the cross-sectionally enlarged section can have a shape adapted to the flow of gas, i.e. it is essentially spherical, better spherical, essentially ellipsoidal, better ellipsoidal, essentially cylindrical, better cylindrical, or essentially parallelepipedal, better parallelepiped.

[0054] Of course, this list is non-limiting. The internal volume of the cross-sectional expansion section can have other geometric shapes. In particular, the shape can have or not have an axis of symmetry or a center of symmetry, and can be a combination of the above shapes.

[0055] The internal volume of the cross-sectional expansion section can be 0.2cm 3 and 250cm 3 between, preferably between 0.5cm 3 and 200cm 3 between, preferably within 1cm 3 and 25cm 3 between.

[0056] The minimum diameter of the capillary may be the diameter of the bottleneck, ie, the diameter of the outlet of the cross-section expansion section in the plasma propagation direction.

[0057] Preferably, the diameter of the inlet of the cross-section-enlarged section is larger than the diameter of the bottleneck.

[0058] The bottleneck may be raised to a predetermined potential. The predetermined potential may be selected so as to maintain the cool plasma in the cross-sectionally enlarged section, the predetermined potential being modified to allow the cool plasma to move towards the plasma outlet.

[0059] In a particular embodiment, the capillary comprises a plurality of plasma outlets, and the cross-sectionally enlarged section comprises a plurality of bottlenecks, each bottleneck leading to one of the plasma outlets.

[0060] Alternatively, the capillary comprises a plurality of plasma outlets, for each plasma outlet a cross-section enlarging section being provided in the capillary.

[0061] The ratio of the maximum diameter of the cross-sectional expansion section to the diameter of the supply inlet and / or the ratio of the maximum diameter of the cross-sectional expansion section to the diameter of the bottleneck can be between 1 and 1000, preferably between 1 and 500, more preferably between 1 and 50.

[0062] The ratio of the maximum diameter of the expanded cross-section to the minimum diameter of the capillary may be between 2 and 40.

[0063] In a particular embodiment, the distal portion is flared.The capillary tube may have a cross section of minimum diameter between the enlarged cross section and the flared distal portion.

[0064] Alternatively, the diameter of the distal portion of the capillary tube remains constant.

[0065] The expanded cross-sectional section may have a wall having a thickness less than that of the wall of the distal portion.

[0066] The ratio of the wall thickness of the distal portion to the wall thickness of the expanded cross-section may be between 1 and 4.

[0067] The cross-section enlarged section may be made of a different material than the capillary tube. Preferably, the cross-section enlarged section is made of the same material as the capillary tube and is formed integrally with the capillary tube.

[0068] The capillary comprising at least one inert gas supply inlet, at least one plasma outlet, a plasma generation region and a cross-section expansion section can be manufactured by molding or blow molding, or even by additive manufacturing.

[0069] The capillary tube comprising at least one inert gas supply inlet, at least one plasma outlet, a plasma generation region and a cross-section expansion section may be made of glass or any insulating material having a high dielectric constant.

[0070] The capillary tube comprising the at least one inert gas supply inlet, the at least one plasma outlet, the plasma generation region and the cross-sectional expansion section may be integral.

[0071] The maximum diameter of the capillary is preferably less than 3 mm, more preferably less than 1 mm.

[0072] The capillary tube may be partially detachable. In particular, the distal portion may be detachable. Preferably, the portion downstream of the plasma generation region is detachable, i.e., it may be detached / unscrewed from the portion comprising the plasma generation region and the inert gas supply inlet.

[0073] The detachable downstream part and the upstream part comprising the plasma generation zone and the inert gas supply inlet may have complementary shapes. In particular, the upstream part may have a shape complementary to a plurality of different detachable downstream parts.

[0074] ignition

[0075] The device according to the present invention may include a high-voltage electrode fixed to the outer wall and / or inner wall of the capillary, and the device is configured so that the electrode transmits a first electric signal and a second electric signal having two different frequencies, the frequency of the first electric signal being defined so that when the electrode transmits the first electric signal, the inert gas introduced into the capillary and subjected to the voltage of the first electric signal generates plasma, the frequency of the second electric signal being defined so as to generate a pulse that triggers the propagation of the plasma toward 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.

[0076] The second signal advantageously triggers and / or accelerates the propagation of the plasma in the capillary.

[0077] The second signal in particular makes it possible to adjust the plasma dose ejected from the device.

[0078] Plasma dose refers to the amount of plasma energy delivered to the target.

[0079] In one embodiment of the invention, the first electrical signal is a carrier wave modulated by the second signal. Such an embodiment advantageously makes it possible to significantly reduce the electromagnetic noise generated by the plasma jet device.

[0080] In another embodiment, the first electrical signal and the second electrical signal are transmitted via a first electrode and a second electrode, respectively, the first electrode being positioned upstream of the second electrode in the plasma propagation direction.

[0081] The second electrode may be positioned downstream of the cross-sectional expansion section in the direction of plasma propagation.

[0082] The second electrode may be positioned in the distal portion of the capillary.

[0083] In a particular embodiment, the device may comprise at least two second electrodes, for example positioned in a bottleneck of the device according to the invention, said bottleneck comprising a section with an enlarged cross section, and in a distal portion of the capillary.

[0084] The first electrode and / or the second electrode may be positioned outside or within a wall of the device.

[0085] The device may comprise a switch which emits the second electrical signal when the switch is closed. Thus, the second electrical signal may only be delivered when the switch is open, for example when a button is pressed.

[0086] The first signal may be a DC, AC, pulse or mixed signal.

[0087] The second signal may be a DC, AC or pulse signal.

[0088] Advantageously, the apparatus according to the invention allows for better control of the plasma dose output from the apparatus.

[0089] Parameter Control

[0090] The device according to the invention may comprise one or more sensors, for example selected from: a voltage sensor, a power sensor, a frequency sensor, a flow sensor, a distance sensor or a thermal sensor.

[0091] The sensor may be configured to measure the power of the plasma output from the plasma diffuser and / or the plasma output from the plasma generator.

[0092] The sensor may be configured to measure a voltage between plasma output from the plasma diffuser and a region to which the plasma is to be applied, or a voltage between plasma output from the plasma generator and a region to which the plasma is to be applied.

[0093] The sensor may be configured to measure temperature during application of the cold plasma to the region to which the plasma is to be applied.

[0094] Preferably, the device according to the invention further comprises a control module configured to analyze the measurement results generated by the one or more sensors.

[0095] The control module can be configured to modify, based on analytical measurement results generated by one or more sensors, a voltage or frequency of an electrical signal delivered to generate plasma in the plasma generation region, a voltage or frequency of an electrical signal delivered to trigger or accelerate propagation of plasma in the capillary, a plasma dose ejected by the device to a target, a target corresponding to an area to which the plasma is to be applied, a plasma temperature at a plasma outlet of the capillary, a pressure in the plasma generation region, an inert gas pressure in the capillary, a pressure in the cross-sectional expansion section, and an inert gas flow rate at a supply inlet.

[0096] In one embodiment, the control module displays the measurement results and / or an analysis of the measurement results on a digital interface. The operator can then easily modify the frequency, voltage, pressure and / or flow rate to adapt the desired plasma dose output from the device and / or select a specific plasma regime.

[0097] Cold plasma exists in a variety of states, and its discharge type varies depending on the production conditions (diffuse jet discharge, filamentary discharge, hollow cathode discharge).

[0098] The mode of the plasma state refers to an operating mode of the plasma that allows a specific type of discharge to be achieved.

[0099] The device according to the present invention advantageously allows real-time adjustment of the delivered plasma dose, facilitating application and ensuring safety of the treatment.

[0100] 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 controllable independently of each other.

[0101] How to use

[0102] According to another aspect of the invention, the 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 cold plasma jet device.

[0103] The porous material may comprise pores having a median diameter between 1 μm and 1 mm, more preferably between 10 μm and 500 μm, more preferably between 40 μm and 100 μm, more preferably between 50 μm and 80 μm.

[0104] The porous material may have a thickness between 100 μm and 5 cm.

[0105] The porous material may have a variable thickness. Preferably, the porous material has a constant thickness.

[0106] The porous material may be made of a dielectric, a semiconductor, a metal, or a metal covered with a dielectric. The porous material is preferably made of a dielectric.

[0107] Preferably, the porous material is made of a sintered ceramic, preferably a sintered glass including, for example, a high-k material such as alumina or perovskite.

[0108] The porous material according to the invention can be used as a plasma diffuser in any field of application where cold plasma is used, in particular for applications involving surface treatment or implantation or bonding or propulsion.

[0109] Preferably, the invention relates to the use of the porous material according to the invention as a plasma diffuser in medical applications.

[0110] The various aspects of the invention may be combined with one another. In particular, the device according to the invention may comprise a plasma diffuser and a cross-section enlarging section.

[0111] The terms "upstream", "downstream", "inlet" and "outlet" are defined relative to the direction of propagation of the inert gas and the plasma. The terms "inside", "outside", "inner" and "outer" are defined relative to the position of the plasma with respect to the device, where the plasma is located inside the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0112] The invention may be better understood upon reading the following detailed description of non-limiting embodiments of the invention and examining the accompanying drawings, in which:

[0113] [ Figure 1 ] Figure 1 schematically shows a longitudinal section of a plasma generating device illustrating the generation of cold plasma,

[0114] [ Figure 2 ] Figure 2 Schematically shows a longitudinal section through a plasma jet device according to the invention including a plasma diffuser,

[0115] [ Figure 3 ] Figure 3 shows a longitudinal section through a plasma jet device according to the invention comprising a plasma diffuser,

[0116] [ Figure 4a ]、[ Figure 4b ]、[ Figure 4c ]、[ Figure 4d ]and[ Figure 4e ] Figure 4a 、 4b 4c, 4d and 4e illustrate different embodiments of an apparatus comprising a plasma diffuser according to the present invention,

[0117] [ Figure 5 ] Figure 5 Schematic diagram showing the application of plasma to an area by a plasma jet device,

[0118] [ Figure 6 ] Figure 6 It is a diagram illustrating that plasma Figure 5 a diagram of the spread and diffusion of equipment;

[0119] [ Figure 7 ] Figure 7 shows, among other things, a plasma jet device comprising a section with an enlarged cross section,

[0120] [ Figure 8 ] Figure 8 shows a plasma jet device according to the invention comprising a section with an enlarged cross section,

[0121] [ Figure 9 ] Figure 9 is a schematic diagram showing a bottom perspective view of an apparatus according to the invention comprising a section with an enlarged cross section,

[0122] [ Figure 10 ] Figure 10 is an example of an apparatus according to the invention comprising a cross-section enlarging section and a plasma diffuser.

[0123] In the rest of the specification, the same or functionally identical elements will be indicated by the same reference numerals. The description of each of the figures will not be repeated with reference to each figure, and only the main differences between the embodiments will be mentioned. DETAILED DESCRIPTION

[0124] Figure 1 The operation of a prior art plasma jet device 1 is illustrated.

[0125] Conventionally, cold plasma is generated at room temperature in a dielectric tube 10 containing an inert gas 12. Electrodes 14 mounted on the dielectric tube 10 generate an electromagnetic field. Cold plasma 16 is generated by subjecting the inert gas 12 to the electromagnetic field. A cold plasma jet 16 is ejected from the apparatus 1.

[0126] Figure 2 A longitudinal section through a plasma jet device 2 according to the invention including a plasma diffuser 28 is schematically shown.

[0127] The device 2 comprises, among other things, a capillary 20 comprising at least one inert gas supply inlet 22 for supplying an inert gas 12, a plasma generation region 24, at least one plasma outlet 26, and a plasma diffuser 28 placed in the capillary outlet path, the plasma diffuser 28 being positioned 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 having a median pore size between 0.1 μm and 5 mm, preferably between 1 μm and 1 mm, and more preferably between 10 μm and 0.5 mm.

[0128] Upon exiting the capillary, the plasma 16 spreads uniformly over a large application area.

[0129] The inert gas 12 may be helium, argon, neon or a mixture of gases, such as argon with 5% oxygen. Preferably, the inert gas is helium.

[0130] The flow rate of the inert gas may be between 0.2 L / min and 5 L / min, preferably about 1 L / min.

[0131] At least one high voltage electrode 14 is fixed to the outer wall of the capillary, allowing plasma to be generated in the plasma generation region 24 by the inert gas 12 introduced through the supply inlet 22 .

[0132] The electrodes are capable of delivering a sinusoidal electrical signal having a frequency between 50 Hz and 100 kHz, preferably about 10 kHz, and a voltage between 1 kV and 30 kV, preferably between 2 kV and 4 kV.

[0133] The second electrode 30 may be fixed to the wall of the capillary 20 downstream of the first electrode 14 in the propagation direction of the plasma.

[0134] The second electrode can be a low voltage or high voltage electrode. Preferably, the second electrode is a low voltage electrode, thereby limiting the electromagnetic noise generated by the device 2.

[0135] The second electrode advantageously triggers or accelerates the propagation of the cold plasma 16 by capillary action in the capillary tube 20 .

[0136] The second electrode may be controlled by a control module (not shown).

[0137] In particular, the control module can be configured to allow a user to adjust 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 so that when the switch is closed, voltage is delivered via the second electrode, and when the switch is open, no voltage is delivered via the second electrode.

[0138] In a particular embodiment of the invention, a single electrode 14 transmits the first and second electrical signals, for example via a modulated signal comprising a carrier wave of frequency f and a lower frequency signal, the frequency of the lowest frequency signal.

[0139] The high frequency carrier wave allows the generation of a cold plasma and the lower frequency signal allows the triggering and / or acceleration of the propagation of the cold plasma.

[0140] The one or more electrodes 14; 30 are preferably positioned against the outer surface of the capillary wall. The plasma thus generated is isolated from the one or more electrodes by the thickness of the capillary wall and can come into contact with the organism without risk of electric shock or heating.

[0141] The porous material 28 may include pores having a median diameter between 1 μm and 5 mm.

[0142] The thickness of the porous material e 28 It can be between 100 μm and 5 cm.

[0143] The thickness of the porous material e 28 Preferably, the thickness e of the porous material is 28 Keep it constant.

[0144] Figure 3 Another embodiment of the device 2 according to the invention is illustrated. Figure 2 The example shown in FIG1 differs in particular in that it comprises a flared distal portion 20 a in which is located a plasma diffuser 28. The combination of the flared distal portion and the plasma diffuser made of a porous material according to the invention makes it possible to significantly increase the application area of ​​the cold plasma output from the device.

[0145] The plasma diffuser 28 may be placed at the distal end of the capillary, e.g. Figure 4a 、 Figure 4c and Figure 4d As shown in .

[0146] Or, as Figure 4b As shown in FIG, the plasma diffuser 28 can be placed at the distal end portion of the capillary, inside the capillary, and not necessarily at its edge. In particular, the distance d less than or equal to 10 mm 28,26 The plasma outlet 26 may be separated from the porous material 28 .

[0147] The apparatus according to the invention may comprise a plurality of inert gas supply inlets 22 , possibly a plurality of plasma generation regions 24 and a plasma outlet 28 . Figure 4c Such an example is shown in .

[0148] The apparatus according to the present invention may comprise a plurality of plasma outlets 26, and a plasma diffuser 28 may be placed in the path of each outlet 26 of the capillary, such as Figure 4d As shown in the diagram.

[0149] The number of plasma outlets 26 is not limited to 1 or 2. The device according to the invention may comprise more than two plasma outlets, in particular the capillary 20 may comprise 3 plasma outlets. Preferably, the number of plasma outlets is between 1 and 100.

[0150] The device according to the invention can accommodate modular, detachable and interchangeable plasma outlets or plasma heads. In particular, the plasma outlet can be mechanically fixed to the capillary.

[0151] like Figure 4e As shown schematically in FIG, the device according to the present invention may comprise a plurality of capillaries 20.

[0152] The apparatus according to the present invention comprising a plurality of capillaries 20 may comprise capillaries that differ from one another. The capillaries 20 may differ from one another in the number of supply inlets 22, the number of plasma outlets 26, the presence of one or more plasma diffusers 28, the presence of a cross-sectional expansion section 60, the maximum or minimum diameter of the capillaries, the thickness of the capillary walls, or the presence of a flared distal portion 20a. This list is not intended to be limiting.

[0153] Figure 6 is a diagram illustrating the propagation of plasma in a capillary 20 including a porous material 28' on the plasma exit path.

[0154] The results shown in this figure are obtained by using Figure 5 The device shown in was obtained experimentally, wherein the porous material 28 ′ comprises pores with a median diameter between 40 μm and 100 μm.

[0155] During the experiment, plasma was generated in a capillary 20 subjected to an electromagnetic field by means of an annular high-voltage copper electrode 14. The plasma was applied to a glass target area 4, under which an aluminum strip was deposited. A space of 5 mm separated the plasma outlet 26 of the capillary from the target area 4. The electrode 14 generated an electrical signal with a voltage of approximately 4.4 + / - 0.30 kV and a frequency of 15 kHz.

[0156] Figure 6 The x-axis and y-axis in the graph represent the number of pixels, and one pixel is equal to 50 μm.

[0157] In this figure, one can see in particular a first stage 51 in which the plasma propagates along the capillary 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 passes through the porous material 28 ′ and is applied to the surface 4 .

[0158] It can be seen that the diffusion of the plasma is uniform and the plasma extends over a relatively large area.

[0159] Figure 7 A plasma jet device 3 according to the invention is shown, comprising a cross-sectional widening section 60 .

[0160] Figure 7 The device 3 shown in the figure comprises a capillary 20 including an inert gas supply inlet 22, a plasma generation region (plasma is generated by the electrode 14) and a plasma outlet 26; downstream of the plasma generation region and upstream of the distal end portion 20a of the capillary, the capillary comprises a cross-sectional expansion section 60.

[0161] In one embodiment, the expanded cross-sectional section 60 may include the plasma generation region 24 .

[0162] The ratio D of the maximum diameter to the height of the cross-sectionally enlarged section 60 is p,max / h p Can be between 0.1 and 100.

[0163] The cross-sectional widening advantageously opens into the bottleneck 62 in the direction of the plasma outlet 26 .

[0164] The cross-sectionally enlarged section 60 may be located at a distance D between 0 cm and 10 cm from the plasma outlet.

[0165] Diameter d of the expanded cross-section p The diameter d of the cross-sectional enlargement section may be variable, in particular it may first increase and then decrease from upstream to downstream. p It can decrease from upstream to downstream.

[0166] The interior volume of the cross-sectionally enlarged section may have a shape that is substantially spherical, more spherical, substantially ellipsoidal, more ellipsoidal, or substantially cylindrical, more cylindrical. These examples are non-limiting.

[0167] The internal volume of the cross-sectional expansion section can be 0.2cm 3 and 250cm 3 between.

[0168] The minimum diameter of the capillary can be the diameter of the bottleneck d s .

[0169] In a particular embodiment, the capillary comprises a plurality of plasma outlets, and the cross-sectionally enlarged section comprises a plurality of bottlenecks 62, each leading to one plasma outlet. Figure 9 An example of such an embodiment is shown in . Figure 9 A bottom view of a capillary tube 20 comprising three plasma outlets 26 and a section 60 with an enlarged cross section is shown.

[0170] Alternatively, for each plasma outlet, a cross-section enlargement section is provided in the capillary.

[0171] The maximum diameter of the cross-sectional expansion section and the inlet diameter d of the cross-sectional expansion section e The ratio may be between 1 and 1000, preferably between 1 and 500, more preferably between 1 and 50.

[0172] The maximum diameter of the cross-section expansion section and the diameter of the bottleneck d s The ratio may be between 1 and 1000, preferably between 1 and 100, more preferably between 1 and 50.

[0173] Preferably, the diameter d of the inlet of the cross-sectionally enlarged section is e Larger than the diameter d of the bottleneck s .

[0174] This advantageously allows increasing the propagation speed of the plasma in the distal portion of the capillary by the Venturi effect.

[0175] The diameter of the distal portion 20a of the capillary can be kept constant, as Figure 7 As shown in .

[0176] In one particular embodiment, the distal portion 20a is flared.

[0177] like Figure 8 As shown in the example of FIG, the cross-sectionally enlarged section may have a thickness e p Than the thickness of the wall of the distal part e s Small wall.

[0178] The thickness e of the wall of the distal part s The thickness of the wall of the expanded cross-section e p The ratio e s / e p Can be between 1 and 4.

[0179] The maximum diameter of the capillary is less than 3 mm, preferably less than 1 mm.

[0180] The device according to the invention may comprise sensors 641 , 642 , in particular optical sensors 641 , thermal sensors or voltage sensors 642 .

[0181] The sensors 641, 642 can transmit the measurement results to the control module 66, which can adjust the plasma dose delivered from the device through a feedback mechanism, preferably by adjusting the treatment time, power (voltage and / or frequency delivered via the high-voltage power supply 70 to the electrode 14 for generating plasma), power (voltage or frequency delivered via the high-voltage power supply to another electrode fixed to the wall (preferably fixed to the outer wall) of the capillary, preferably downstream of the electrode for generating plasma, which is, for example, configured to trigger or accelerate the propagation of plasma to the plasma outlet) and / or the flow rate of the inert gas at the inert gas supply inlet 22.

[0182] The sensor may comprise a voltage sensor that measures a voltage difference along the capillary.

[0183] The sensor may include a voltage sensor 642 that measures the voltage difference between the capillary and the region 4 to which the plasma is to be applied.

[0184] The sensor may include a temperature sensor that measures the temperature of the plasma outlet or the temperature in the region 4 to which the plasma is to be applied.

[0185] The sensor may include a flow rate sensor that measures the flow rate of the inert gas entering the supply inlet.

[0186] The sensors may include biosensors, ie sensors that allow for the detection and conversion of a biochemical signal into a quantifiable physical signal.

[0187] The sensor comprises, for example, an electrocardiogram fixed to the area 4 to which the plasma is to be applied.

[0188] The control module 66 is capable of modifying 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 electrode fixed to the wall of the capillary, preferably fixed to the outer wall, and / or the flow rate of the inert gas at the inert gas supply inlet 22, so as to adjust the plasma dose ejected from the device.

[0189] In a particular embodiment of the invention, the control module 66 does not adjust the plasma dose ejected from the device by a feedback mechanism, but rather transmits the measurements delivered by the sensors, or an analysis of the measurements delivered by the sensors, to the control interface 68 via the digital communication means 72 .

[0190] The control interface 72 allows the user to manually control the plasma dose ejected from the device and to adjust said plasma dose according to the measurements delivered by the sensors 641 , 642 .

[0191] In particular, the user can modify the power, voltage and / or frequency delivered by the high-voltage power supply 70 to the electrode 14 for generating plasma, the power, voltage and / or frequency delivered by the current source to another electrode fixed to the wall of the capillary (preferably fixed to the outer wall) preferably downstream of the electrode for generating plasma, the other electrode being configured, for example, to trigger or accelerate the propagation of the plasma towards the plasma outlet, and / or the flow rate of the inert gas at the inert gas supply inlet 22, and / or the distance from the plasma outlet 26 to the region 4 to which the plasma is to be applied.

[0192] Figure 10 An embodiment of a device according to the invention is shown, which comprises a plasma diffuser 28 and a cross-sectional enlargement section 60 .

[0193] example

[0194] Four plasma jet devices were compared.

[0195] This comparison enables the measurement of the maximum area over which the plasma can extend uniformly through the plasma jet when the plasma is generated and applied by means of one of the following 4 devices: MED (Neoplas GmbH, Greifswald, Germany), (CINOGY GmbH, Duderstadt, Germany), SteriPlas (Adtecplasma Technology, Adtec Europe, Hounslow, UK) and an apparatus according to the invention comprising a plasma diffuser.

[0196] The MED is a portable device that has a continuously generated medical plasma source and includes a pencil-shaped applicator that uses argon as a carrier gas to deliver a cold atmospheric pressure plasma jet. Typical plasma plume lengths are 8 to 12 mm and diameters are 1 mm. The plasma jet is directed vertically over the target with precise and arbitrary 3D motions of approximately 5 mm / s, resulting in average treatment times of 30 to 60 s / cm 2 .then, MED delivers a non-diffusing jet focused on one point. The effective treatment area is reduced to a few mm 2 .

[0197] It is a plasma device that allows the treatment of large areas. It is equipped with multiple configurable plasma heads that allow coverage of up to 27cm 2The plasma source is based on the concept of dielectric barrier discharge (DBD). The carrier gas can be argon or air. However, in DBD-based devices, the generated plasma behaves differently between the two alternating plasma discharges, and the lack of uniformity in the transferred plasma requires a high level of user skill. Furthermore, the device is in direct mechanical contact with the target.

[0198] The SteriPlas is a large, wheeled medical device with an articulated arm and a treatment head that releases cold argon-based plasma to the treatment area. The plasma torch has six electrodes, and argon is used as a carrier gas to deliver the gas flow to the target. The aperture of the plasma torch has a diameter of 3.5 cm, allowing for up to 12 cm 2 treatment area.

[0199] The device according to the first aspect of the invention makes it possible to cover 1 to 50 cm by the initial propagation of a single plasma jet. 2 area, especially without the need for contact with the target.

[0200] It should now be clear that the device according to the present invention allows for improved plasma propagation. Not only can larger areas be treated more quickly and evenly, but it also allows for greater adaptability and higher dose accuracy. This device is particularly advantageous for treating burns, such as those with severe burns. Generally speaking, this device is suitable for treating any type of wound, especially various types of chronic wounds.

[0201] It is not obvious that fritted glass can be used in particular as a porous material in plasma diffusers in cold plasma jet devices. In particular, even though the use of fritted glass in plasma jet devices is well known in the prior art, its use as a diffuser activated by a plasma jet has never been envisaged due to its mechanical properties (such as resistance to corrosion, wear, compression, high temperatures and chemicals) that enable it to withstand the conditions of plasma generation.

[0202] The present invention allows for dynamic control of the plasma dose ejected from the plasma jet device, thus allowing the user to better tailor each treatment to the wound or clinical situation.

[0203] Of course, the invention is not limited to the examples of embodiment that have just been described.

[0204] In particular, the apparatus according to the present invention may include a safety system configured to control the dose of plasma ejected from the apparatus, and / or the current delivered, and / or the temperature of the plasma output from the apparatus, and / or the power of the plasma, and / or the pressure of the inert gas in the inert gas cylinder supplying the inert gas supply inlet of the capillary tube, and / or the pressure of the inert gas in the capillary tube, in particular, when the capillary tube includes a cross-sectional expansion section, the pressure of the inert gas in the cross-sectional expansion section. For example, the safety system may be a fast circuit breaker, or a microcontroller that controls the high-voltage power supply of the electrode used to generate the plasma.

[0205] The device according to the invention is preferably designed with redundancy, in particular in order to comply with regulations regarding medical devices.

[0206] In particular, the device according to the present invention is preferably configured to comply with all or part 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 (if RIPH1), DIN SPEC 91315. This list is not exhaustive.

[0207] The expressions "comprising" and "comprising a" must be understood as being synonymous with "comprising at least one".

Claims

1. A cold atmospheric pressure plasma jet device (3), comprising: at least one capillary tube (20) comprising at least one inert gas supply inlet (22), a plasma generation region (24), and at least one plasma outlet (26); The capillary tube includes an enlarged cross-section section (60) downstream of the plasma generation region and upstream of a distal portion of the capillary tube.

2. The device according to the preceding claim, the cross-section expansion section being located at a distance from the plasma outlet of between 0 cm and 10 cm, preferably between 0 cm and 7 cm, and more preferably between 0 cm and 5 cm.

3. The device according to any of the preceding claims, wherein the diameter of the section with widened cross-section is variable, in particular first increasing and then decreasing from upstream to downstream.

4. An apparatus according to any one of the preceding claims, wherein the internal volume of the cross-sectionally enlarged section has a shape that is essentially spherical, better spherical, essentially ellipsoidal, better ellipsoidal, essentially cylindrical, better cylindrical or essentially parallelepipedal, better parallelepipedal.

5. The device according to claim 4, wherein the internal volume of the cross-sectionally enlarged section is 0.2 cm 3 and 250cm 3 between, preferably between 0.5cm 3 and 200cm 3 between, and more preferably within 1 cm 3 and 25cm 3 between.

6. The device according to any one of the preceding claims, the smallest diameter of the capillary tube being the diameter of the bottleneck into which the section of enlarged cross section opens.

7. Apparatus according to any one of the preceding claims, the diameter of the inlet of the section of widening cross-section being greater than the diameter of the bottleneck into which the section of widening cross-section opens.

8. Apparatus according to any preceding claim, the bottleneck into which the section of enlarged cross-section opens being raised to a predetermined electrical potential.

9. The device according to any one of the preceding claims, the capillary comprising a plurality of plasma outlets, the section of enlarged cross section opening into a plurality of bottlenecks, each bottleneck opening into one plasma outlet.

10. The apparatus according to any one of claims 1 to 8, the capillary comprising a plurality of plasma outlets, for each plasma outlet a cross-sectional enlargement section being provided in the capillary.

11. Apparatus according to any one of the preceding claims, the section of enlarged cross section having a width / height ratio between 0.1 and 1000, the width corresponding to the maximum inner diameter of the section of enlarged cross section.

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