Systems and methods for removing and replacing a conductive adhesive layer on an electrode array - Patents.com

Abstract

The device may include a subassembly having one or more electrode elements, each electrode element having a skin-facing side and a skin-facing surface. The device may further include a skin-contact layer including a conductive adhesive. The skin-contact layer may be coupled to the subassembly and disposed on the skin-facing side of the electrode elements. The conductive adhesive is electrically coupled to the electrodes and configured to contact the skin of the subject. At least a portion of the skin-contact layer is selectively removable from the subassembly.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority and the filing date of U.S. Provisional Application No. 63 / 291,013, filed December 17, 2021, the entirety of which is incorporated herein by reference for all purposes. [Background technology]

[0002] Tumor Treating Field (TT Field) Therapy is a proven approach to treat tumors using alternating electric fields with frequencies between 50KHz and 1MHz. The alternating electric field is induced by electrode assemblies (e.g., an array of capacitively coupled electrodes, also called a transducer array) placed on opposite sides of the subject's body. When an alternating voltage is applied between the opposing electrode assemblies, an alternating current flows through the electrode assemblies into the subject's body. And higher currents are strongly correlated with higher therapeutic effects.

[0003] Figure 1A is a schematic diagram of a prior art electrode assembly 40 including nine prior art electrode elements labeled X1-X9, and Figure 1B is a cross-sectional schematic diagram of electrode elements X7-X9 of electrode assembly 40 taken along the dashed line in Figure 1A.

[0004] As shown in FIG. 1B, electrode element X7 (exemplary) includes a metal layer (shown with diagonal hatching) and a ceramic (dielectric) layer. A layer of conductive hydrogel is provided between each ceramic layer and the subject's skin to ensure good electrical contact between the electrode element and the body. An AC voltage from an AC voltage generator (not shown) is applied to the metal layer of the electrode element in the opposing electrode assembly to generate a TT field within the subject's body. An adhesive cover (bandage) is typically provided over the electrode assembly to hold the electrode assembly in place during use.

[0005] During use, the hydrogel and skin beneath the electrode elements heat up, and safety considerations require that the skin temperature be maintained below a safety threshold (e.g., 41° C.). Because the majority of the heat occurs beneath electrode elements X1-X9 (as shown in FIGS. 1C and 1D), prior art electrode assemblies have hot spots beneath the electrode elements and cooler regions located between the electrode elements, which in turn limit the amount of current that can be delivered through the prior art electrode assemblies.

[0006] The hydrogel layer(s) of the electrode assembly may also have various problems. For example, the hydrogel has a limited shelf life, necessitating moisture-proof packaging, which increases the packaging costs of the electrode assembly. In addition, the signal passing through the hydrogel may vary depending on the specific water content within the hydrogel, and the hydrogel may fail with too much or too little water. Furthermore, electrode assemblies with hydrogel layers must be replaced frequently during use, and many patients have adverse reactions (e.g., allergic reactions) to the hydrogel.

[0007] Conductive hydrogels typically have a shorter life span than other electrode assemblies, however, the hydrogel is typically integral to the electrode assembly, and therefore, when the hydrogel expires or becomes contaminated, the entire electrode assembly must be discarded and replaced. Summary of the Invention [Means for solving the problem]

[0008] In one aspect, a device is disclosed that includes a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface. A skin-contact layer may include a conductive adhesive. The skin-contact layer may be coupled to the subassembly and disposed on the skin-facing side of at least one electrode element. The conductive adhesive may be electrically coupled to an electrode and configured to contact the skin of a subject. At least a portion of the skin-contact layer may be selectively removable from the subassembly.

[0009] The method may include bonding a skin contact layer comprising a conductive adhesive to a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface, such that the skin contact layer is disposed on the skin-facing side of the at least one electrode element.

[0010] The method may include removing a skin contact layer from an assembly, the assembly may include at least one electrode element having a skin-facing surface. The assembly may further include a plurality of conductive adhesive layers including an outermost conductive adhesive layer forming a plurality of the skin contact layers and at least one intermediate layer disposed between the at least one electrode element and the skin contact layer. The step of removing the skin contact layer from the assembly may include removing the skin contact layer from the at least one intermediate layer to expose the at least one intermediate layer to form a new skin contact layer. [Brief description of the drawings]

[0011] [Figure 1A] FIG. 1 is a schematic diagram of a prior art electrode assembly. [Figure 1B] FIG. 1B is a cross-sectional view of an electrode element of a prior art electrode assembly taken along the dashed line in FIG. 1A. [Figure 1C] 1 is a cross-sectional view showing the heating characteristics of a prior art electrode element. [Figure 1D] FIG. 1C is a cross-sectional view illustrating the heating characteristics of a hypothetical modification to the electrode element of FIG. [Diagram 2] 1 is a schematic side view of an electrode assembly disclosed herein. [Diagram 3] FIG. 2 is a schematic side view of an electrode assembly receiving a skin contact layer. [Figure 4] FIG. 2 is a side schematic view of an electrode assembly with the skin contact layer removed. [Diagram 5] FIG. 1 is a schematic plan view of an electrode assembly including electrode elements E1, E2 used to apply a TT field to a subject's body. [Figure 6A] 6 is a cross-sectional view of another embodiment including electrode elements E1, E2 taken along the dashed line in FIG. 5. [Figure 6B] FIG. 6B is a cross-sectional view showing the heat generation characteristics of the embodiment of FIG. 6A. [Figure 7] 6 is a cross-sectional view of yet another embodiment including electrode elements E1, E2 taken along the dashed line in FIG. 5. [Figure 8] FIG. 13 is a cross-sectional view of yet another embodiment including a single electrode element E1. [Figure 9] FIG. 7 is a block diagram of a system incorporating two electrode assemblies used to apply a TT field to the subject's body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Various embodiments are described in detail below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which: The present application describes examples of exemplary electrode assemblies that can be used, for example, to deliver a TT field to a subject's body to treat one or more cancers or tumors located in the subject's body.

[0013] The present invention may be more readily understood by reference to the following detailed description, examples, drawings and claims, as well as the accompanying description, but it is to be understood that the invention is not limited to the particular apparatus, devices, systems and / or methods disclosed, unless expressly stated, as such may, of course, vary.

[0014] The names are provided for convenience only and should not be construed as limiting the invention in any manner. Embodiments presented under any heading or in any portion of this disclosure may be combined with embodiments presented under the same or other headings or portions of this disclosure.

[0015] The invention includes combinations of the elements described herein in all possible variations thereof unless otherwise indicated herein or clearly contradicted by context.

[0016] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0017] Conductive hydrogels typically have a shorter life span than other electrode assemblies. However, it is not possible to remove or replace the current hydrogel skin contact layer. Thus, when the hydrogel expires or becomes contaminated, the entire electrode assembly is discarded and replaced. What is needed is an electrode assembly, and associated method, that allows for the removal and replacement of the skin contact layer.

[0018] Disclosed herein are devices, systems, and methods for adding, removing, or modifying a skin contact layer of a device to provide a new skin contact layer for an electrode assembly. In this manner, the skin contact layer can be modified when it deteriorates (e.g., due to exposure to air, dirt, oil, etc. from the patient), becomes contaminated or may become contaminated, or is otherwise undesirable. As can be appreciated, deterioration of the skin contact layer can lead to reduced adhesion, reduced electrical conductivity, and / or reduced thermal conductivity.

[0019] 2, as shown in FIG. 2, the device 100 may include a subassembly 102 including at least one electrode element 104. Each electrode element 104 may have a skin-facing (front-facing) side 106 and a skin-facing surface 108. A skin-contact layer 110 may be coupled to the subassembly 102 and disposed on the skin-facing side of the at least one electrode element 104. The skin-contact layer 110 may include a conductive adhesive 112 that may be electrically coupled to the electrode and configured to contact the skin of the subject. In all embodiments disclosed herein, the skin-contact layer may optionally be a biocompatible conductive adhesive.

[0020] In some optional embodiments, a first adhesive 114 may bond the skin contact layer 110 to the subassembly 102 .

[0021] In some embodiments, the device 100 may include a plurality of layers 120, each of which is a conductive adhesive 112. The plurality of layers 120 may include an outermost layer forming a skin contact layer 110 and one or more intermediate layers 122 disposed between at least one electrode element 104 and the skin contact layer. The skin contact layer 110 may be bonded to the one or more intermediate layers 122. The skin contact layer 110 may be configured to detach from the one or more intermediate layers 122. In this manner, the skin contact layer 110 may be removed from the subassembly, thereby exposing an immediately adjacent intermediate layer 122 that may function as a skin contact layer. That is, when the skin contact layer is detached from the intermediate layer, the adjacent intermediate layer may be configured to form an outermost skin contact layer. In some optional embodiments, the device 100 may include a plurality of intermediate layers 122 configured to successively form an outermost skin contact layer when each adjacent conductive adhesive layer of the plurality of conductive adhesive layers is detached from the subassembly 102. For example, the device 100 may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more intermediate layers 122. In some optional embodiments, the intermediate layer 122 and the skin contact layer 110 may cooperate to define a total resistance of less than 15 ohms when measured at frequencies between 50 KHz and 1 MHz. Optionally, one or more of the layers of conductive adhesive 120 may include peel tabs inserted at one or more peripheries to facilitate removal of the layer. The peel tabs may be, for example, part of a thin polymer film or part of a release liner.

[0022] In some embodiments, the skin contact layer 110 may comprise a conductive adhesive composite as described herein. In further embodiments, the skin contact layer 110 may comprise a hydrogel.

[0023] In some optional aspects, the subassembly 102 may further include a layer of anisotropic material 130 having a skin-facing (front-facing) side 132, a skin-facing surface 134, and an opposite outward-facing (rear-facing) surface 136. The electrode element 104 may be in electrical contact with the outward-facing surface 136 of the layer of anisotropic material 130. The skin-contact layer 110 may be disposed on the skin-facing side 132 of the layer of anisotropic material 130. In some embodiments, the skin-contact layer 110 may be disposed on the skin-facing surface 134 of the layer of anisotropic material 130. In use, the layer of anisotropic material is believed to help avoid or reduce overheating of the electrode and associated skin discomfort by dissipating both electrical current and heat laterally (in-plane) rather than passing directly through the layer in a concentrated manner (perpendicular to the plane of the skin-contact layer). Optionally, the assembly 100 may include a conductive material 138 disposed between the anisotropic material 130 and the electrode element 104. In some embodiments, the anisotropic material 130 may be disposed in contact between the conductive material 138 and the skin-contacting layer 110. In further aspects, the anisotropic material 130 and / or the conductive material 138 may be omitted.

[0024] The drawings (e.g., FIG. 2) further show leads 90 that supply AC voltage (directly or indirectly from an AC voltage generator (not shown)) to the electrode elements to generate the TT field when the electrode assembly 100 is attached to a subject.

[0025] Optionally, the electrode 104 may include a dielectric (eg, ceramic) material 160 (see, eg, FIGS. 6A and 7).

[0026] How to Add One or More Skin Contact Layers 2 and 3, a subassembly 102 of the device 100 may include at least one electrode element 104 having a skin-facing side 106 and a skin-facing surface 108. The method may include bonding a skin-contact layer 110 including a conductive adhesive 112 to the subassembly 102 such that the skin-contact layer is disposed on the skin-facing side of the at least one electrode element.

[0027] For example, the subassembly 102 may include a pre-existing (e.g., old, used, or otherwise undesirable) skin contact layer 140 prior to bonding the skin contact layer 110, such that the skin contact layer 110 is bonded to the pre-existing skin contact layer 140. In further embodiments, the subassembly 102 does not have a pre-existing skin contact layer prior to bonding the skin contact layer 110. For example, the subassembly 102 may include one or more electrode elements 104, optionally anisotropic layer 130, and optionally a conductive layer 138 between the anisotropic layer and the electrode elements. It is contemplated that additional layers, including conductive adhesive 112, may be sequentially bonded to the subassembly to sequentially form the skin contact layer 110. In some optional embodiments, additional layers may be added until the intermediate layer 122 and the skin contact layer 110 together define a total resistance of more than 15 ohms when measured at frequencies between 50 KHz and 1 MHz.

[0028] In these and other embodiments described herein, the electrode 104 may optionally include a layer of a dielectric (eg, ceramic) material.

[0029] In a further optional embodiment, the existing skin contact layer 140 may be removed prior to bonding the skin contact layer 110. In this manner, the electrical and thermal resistance of the existing skin contact layer 140 can be eliminated.

[0030] In some aspects, the subassembly 102 may include a layer of anisotropic material 130 having a skin-facing (front-facing) side 132, a skin-facing surface 134, and an opposite outward-facing (rear-facing) surface 136, as described above. The electrode element 104 may be in electrical contact with the outward-facing surface 136 of the layer of anisotropic material 130. The skin-contact layer 110 may be disposed on the skin-facing side 132 of the layer of anisotropic material 130. In some embodiments, the skin-contact layer 110 may be disposed on the skin-facing surface 134 of the layer of anisotropic material 130. Optionally, the assembly 100 may include a conductive material 138 disposed between the anisotropic material 130 and the electrode element 104. In some embodiments, the anisotropic material 130 may be disposed in contact between the conductive material 138 and the skin-contact layer 110. In further aspects, the anisotropic material 130 and / or the conductive material 138 may be omitted.

[0031] In some embodiments, the layer of anisotropic material 130 and the skin contact layer 110 may define perimeters 150, 152, respectively. To avoid hot spots of high currents, temperatures, electric fields, and the like, it is advantageous for the perimeter 152 of the skin contact layer and the perimeter 150 of the layer of anisotropic material 130 to coincide. Thus, in some embodiments, the method may further include trimming the perimeter 152 of the skin contact layer 110 to match the perimeter 150 of the layer of anisotropic material. For example, for an anisotropic material 130 having a circular profile, the perimeter 152 may be trimmed such that the skin contact layer is concentric with the layer of anisotropic material 130 and has the same or substantially the same diameter as the layer of anisotropic material 130. Thus, prior to trimming, the skin contact layer 110 may be made larger than the anisotropic material 130 to provide sufficient material for trimming. Optionally, the perimeter 152 may be trimmed prior to bonding the skin contact layer 110 to the subassembly 102. In a further embodiment, the periphery 152 may be trimmed after bonding the skin contact layer 110 to the subassembly 102 .

[0032] In a further embodiment, a jig may be used to align the periphery 152 of the skin contact layer 110 with the periphery 150 of the layer of anisotropic material 130 .

[0033] In various aspects, the skin contact layer 110 may comprise a conductive adhesive composite or hydrogel, as described further herein. In one embodiment, the additional skin contact layer is or comprises a conductive adhesive composite having an in-plane conductivity (xy plane) substantially equal to the conductivity in a direction perpendicular to the plane of the layer (z direction). That is, neither conductivity exceeds the other by more than 1.5 times. In another embodiment, the additional skin contact layer is a conductive adhesive composite having an in-plane conductivity (xy plane) at least 2 times greater than the conductivity in a direction perpendicular to the plane of the layer (z direction). In other aspects, the additional skin contact layer is a conductive adhesive composite having an in-plane conductivity (xy plane) about 1.5 times to about 2 times greater than the conductivity in a direction perpendicular to the plane of the layer (z direction).

[0034] In some aspects, the method includes bonding a plurality of layers, including the skin contact layer 110 (which may include the conductive adhesive 112), to the subassembly 102 such that the plurality of layers constituting the skin contact layer are disposed on the skin-facing side of at least one electrode element, with the skin contact layer being the outermost skin contact layer. The plurality of layers may include two layers, three layers, or more than two layers. For example, two additional layers may include a layer of anisotropic material 130 and the skin contact layer 110. And three additional layers may include a layer of conductive material 138, a layer of anisotropic material, and the skin contact layer. In all of these embodiments, either or both of the skin contact layer 110 and the layer of conductive material 138 may be or may include a conductive adhesive 112, such as a conductive adhesive composite, as described herein. In all of these aspects, other embodiments of the subassembly 102 and methods of bonding the skin contact layer 110 (or the plurality of layers constituting the skin contact layer) to the subassembly may also be suitable to form additional embodiments, as described herein.

[0035] Once the skin contact layer 110 has been applied to the subassembly 102, the skin contact layer 110 may be applied to a patient and a TT field may then be applied to the target area of ​​the patient using the device 100. Prior to or upon expiration of the skin contact layer 110 (e.g., expiration due to degradation), a new skin contact layer may be applied to the subassembly 102 (which may be in the form of multiple layers that make up the skin contact layer, as described above), the new skin contact layer may be applied to the same or a different patient, and a TT field may then be applied to the target area of ​​the patient using the device 100.

[0036] In other embodiments, a kit may be provided that includes a set including any number of layers that constitute the skin contact layer, as described above. For example, a two-layer unit may include a layer of anisotropic material 130 and a skin contact layer 110. A three-layer unit may include a layer of conductive material 138, a layer of anisotropic material, and a skin contact layer. In each unit (two-layer unit or three-layer unit), the outward surface (or surfaces) may be protected by a release layer (or release layers). Thus, a subject utilizing an electrode assembly may be readily provided with multiple replacement units for updating the skin contact layer as needed.

[0037] Method for Removing One or More Skin Contact Layers 2 and 4, the assembly 100 may include at least one electrode element 104 having a skin-facing surface 108. The assembly 100 may include a plurality of layers 120 including a conductive adhesive 112 (conductive adhesive layer). The plurality of conductive adhesive layers 120 may include an outermost conductive adhesive layer defining a skin contact layer 110 and at least one intermediate layer 122 disposed between the at least one electrode element and the skin contact layer 110. Optionally, one or more layers of the plurality of conductive adhesive layers 120 may include a peel tab inserted at one or more peripheries to facilitate removal of the layer. The peel tab may be, for example, part of a thin polymer film or part of a release liner.

[0038] The method may include removing the skin contact layer 110 from the at least one intermediate layer 122 to expose the at least one intermediate layer to define a new skin contact layer. For example, upon removing the skin contact layer 110 from the at least one intermediate layer 122, the at least one intermediate layer may be configured to form an outermost skin contact layer.

[0039] In some optional embodiments, the device 100 may include multiple intermediate layers 122 configured to sequentially form the (outermost) skin contact layer 110 when each adjacent (outermost) conductive adhesive layer of the multiple conductive adhesive layers 120 is separated from the assembly.

[0040] In some optional aspects, the assembly 100 may further include a layer of anisotropic material 130 having a skin-facing side 132, a skin-facing surface 134, and an opposite outward-facing surface 136, as described above. At least one electrode element 104 may be in electrical contact with the outward-facing surface 136 of the layer of anisotropic material 130, and a skin contact layer may be disposed on the skin-facing side 132 of the layer of anisotropic material 130. In some embodiments, the skin contact layer 110 may be disposed on the skin-facing surface 134 of the layer of anisotropic material 130. Optionally, the assembly 100 may include a conductive material 138 disposed between the anisotropic material 130 and the electrode element 104. In some embodiments, the anisotropic material 130 may be disposed in contact between the conductive material 138 and the skin contact layer 110. In further aspects, the anisotropic material 130 and / or the conductive material 138 may be omitted.

[0041] In some embodiments, the plurality of conductive adhesive layers 120 may include a conductive adhesive composite (eg, a conductive adhesive composite disclosed herein) or a hydrogel.

[0042] In some aspects, the method may include removing the skin contact layer 110 (or layers that make up the skin contact layer, as described above) from at least one intermediate layer 122 to expose at least one intermediate layer and define a new skin contact layer. The layers may include two layers, three layers, or more than two layers. For example, the two-layer unit to be removed may include a layer of anisotropic material 130 and a skin contact layer 110. And the three-layer unit to be removed may include a layer of conductive material 138, a layer of anisotropic material, and a skin contact layer. In all of these embodiments, either or both of the skin contact layer 110 and the layer of conductive material 138 may be a conductive adhesive 112, such as a conductive adhesive composite, as described herein. In all of these aspects, other embodiments of the subassembly 102 and methods of removing the skin contact layer 110 (or layers that make up the skin contact layer) from at least one intermediate layer 122, as described herein, may also be suitable in forming additional embodiments.

[0043] Once the skin contact layer 110 has been removed (or the layers constituting the skin contact layer have been removed as described above) to expose a (new) outermost skin contact layer, the outermost skin contact layer may be applied to a patient and the device 100 may be used to apply a TT field to a target area of ​​the patient. Before or upon expiration (e.g., expiration of degradation) of the outermost skin contact layer, the outermost skin contact layer may be removed to expose an adjacent skin contact layer. The adjacent skin contact layer may then be applied to the same or a different patient and the device 100 may then be used to apply a TT field to a target area of ​​the patient. Optionally, after the skin contact layer 110 has been removed (or the layers constituting the skin contact layer have been removed), a new replacement skin contact layer 110 (or the layers constituting the skin contact layer) may be added in its place.

[0044] Typical Configuration Below are examples of configurations of the apparatus and methods disclosed in this specification.

[0045] FIG. 5 is a schematic diagram of an embodiment of an electrode assembly (e.g., device 100) including electrode elements used to apply a TT field to a subject's body. In FIG. 5, only two electrode elements, labeled E1 and E2, are shown, but it is contemplated that in any other aspect, the electrode assembly may include additional electrode elements. In alternative embodiments, the electrode assembly includes only one electrode element. It is noted that FIG. 5 generally illustrates the electrode assemblies, and that these electrode assemblies E1 and E2 may have different configurations (e.g., as described below in connection with FIGS. 6A-9).

[0046] FIG. 6A is a cross-sectional view of a first embodiment of an electrode assembly 100 including electrode elements E1, E2 taken along the dashed line in FIG.

[0047] In the embodiment of FIG. 6A, the electrode assembly 100 includes a sheet of anisotropic material 130 having a front surface (facing the subject's skin in FIG. 6A) and a back surface. The sheet has a first thermal conductivity in a direction perpendicular to the front surface. The thermal conductivity of the sheet in a direction parallel to the front surface is at least twice the first thermal conductivity. In some preferred embodiments, the thermal conductivity of the sheet in a direction parallel to the front surface is at least 10 times the first thermal conductivity. The sheet in the illustrated embodiment of FIG. 6A is also anisotropic in other respects. More specifically, the sheet has a first resistance in a direction perpendicular to the front surface, and the resistance of the sheet in a direction parallel to the front surface is less than half the first resistance. In certain embodiments, the resistance of the sheet in a direction parallel to the front surface is less than 10% of the first resistance.

[0048] In some embodiments, the sheet of anisotropic material 130 is a sheet of graphite. In some embodiments, the sheet of anisotropic material 130 is a sheet of synthetic graphite, such as pyrolytic graphite (e.g., Pyrolytic Graphite Sheet (PGS) available from Panasonic Industries, Kadoma, Osaka, Japan). In other embodiments, the sheet of anisotropic material is a graphite foil made of compressed high-purity exfoliated mineral graphite (e.g., MinGraph® 2010A Flexible Graphite, Mineral Seal Corp., Tucson, Arizona, USA), or a graphitized polymer film, such as a graphitized polyimide film (including, but not limited to, those available from Kaneka Corporation, Moga, Tochigi, Japan). In other embodiments, the anisotropic material may be pyrolytic carbon. In other embodiments, sheets of other conductive materials having anisotropy may be utilized. In some embodiments (e.g., when the anisotropic material sheet is a pyrolytic graphite sheet), the anisotropic material sheet is non-metallic.

[0049] The electrode assembly of FIG. 6A further includes a skin contact layer 110 of conductive adhesive 112 disposed on the front surface of the sheet of anisotropic material 130. The skin contact layer of conductive adhesive is configured to ensure good electrical contact between the device and the body. In some embodiments, the skin contact layer may cover the entire front surface of the sheet of anisotropic material. For example, the skin contact layer may be the same size or larger than the sheet of anisotropic material. In some embodiments, the skin contact layer of conductive adhesive comprises a hydrogel. In these embodiments, the hydrogel may have a thickness between 50 μm and 2000 μm. In other embodiments, the skin contact layer of conductive adhesive comprises a conductive adhesive composite as further disclosed herein.

[0050] The electrode assembly of Figure 6A further includes a first electrode element E1 located at the rear of the sheet. The first electrode element E1 has a first front surface disposed in electrical contact with the rear surface of the sheet 130. In the embodiment of Figure 6A, the first electrode element E1 includes a first layer of dielectric (e.g., ceramic) material 160 having a front surface and a rear surface, and a first layer of metal (shown with diagonal hatching) disposed on the rear surface of the first layer of dielectric material. The front surface of the first dielectric layer is the first front surface of the first electrode element E1.

[0051] The electrode assembly of FIG. 6A further includes a first layer of conductive material 138 disposed between the first front surface of the first electrode element E1 (i.e., the front surface of the first layer of dielectric material) and the rear surface of the anisotropic material sheet 130. The first layer of conductive material facilitates electrical contact between the first front surface of the first electrode element E1 and the rear surface of the sheet. In the illustrated embodiment, the layer of conductive material 138 may be a layer of hydrogel. However, in alternative embodiments, another conductive material (e.g., conductive grease, conductive adhesive, conductive tape, etc.) may be used. For example, the layer of conductive material may include a conductive adhesive composite, as further disclosed herein.

[0052] The electrode assembly may optionally include one or more additional electrode elements. In the illustrated embodiment, the electrode assembly includes a second electrode element E2 disposed at the rear of the sheet. The second electrode element E2 has a second front surface disposed in electrical contact with the rear surface of the sheet 130. The two electrode elements E1 and E2 in FIG. 6A have the same structure. Thus, the second electrode element E2 includes a second layer of dielectric (e.g., ceramic) material having a front surface and a rear surface, and a second layer of metal disposed at the rear surface of the second layer of dielectric material. The front surface of the second layer of dielectric material is the second front surface of the second electrode element E2.

[0053] The first layer of conductive material 138 is located between the second front surface of the second electrode element E2 (i.e., the front surface of the second layer of dielectric material) and the rear surface of the sheet 130. The first layer of conductive material facilitates electrical contact between the second front surface of the second electrode element E2 and the rear surface of the sheet. As described for E1, the conductive material 138 in FIG. 6A may be a hydrogel layer, although in alternative embodiments, another conductive material (such as conductive grease, conductive adhesive, conductive tape, etc.) may be used. For example, the layer of conductive material may include a conductive adhesive composite, as further disclosed herein.

[0054] The metal layers of all of the electrode elements (i.e., E1 and E2 in the illustrated embodiment) may be wired together (e.g., using wires, traces on a flex circuit, etc.) to a lead 90. The lead 90 supplies an AC voltage from an AC voltage generator (not shown) to the electrode elements 104 to generate the TT field when the electrode assembly 100 is applied to a subject.

[0055] Optionally, in all of the embodiments disclosed herein, the electrode assembly may include a flexible self-adhesive backing 55 (as shown in Figures 6A, 7, and 8) configured to support the sheet of anisotropic material 130, the first electrode element E1 (and any other electrode elements present in the electrode assembly), and a layer of conductive material 138 so that a skin-contact layer of conductive adhesive can be placed against the subject's skin.

[0056] As mentioned above, Figure 5 is a schematic plan view of an electrode assembly including electrode elements E1 and E2. This view of Figure 5 (not to scale) also illustrates that the area of ​​sheet 130 can be larger (e.g., at least 10 times larger) than the combined area of ​​electrode elements E1, E2. When an AC voltage is applied to electrode elements E1 and E2, heat spreads throughout the sheet, minimizing or eliminating hot spots.

[0057] This reduction in hot spots (compared to the prior art) becomes evident by comparing Figure 1C with Figure 6B. More specifically, Figure 1C shows the current distribution and heating of prior art electrode elements, where each electrode element is disposed on a conductive hydrogel layer that is approximately the same size as the electrode element. As shown in Figure 1C, all of the current passes through the hydrogel layer directly beneath the electrode element, resulting in a hot spot directly beneath the electrode element.

[0058] One might initially think that this problem could be solved by increasing the area of ​​the hydrogel to cover all the areas between the electrode elements. However, this is not the case. More specifically, Figure 1D shows the current distribution and heating of this hypothetical electrode assembly. As shown in Figure 1D, all of the current still passes through the hydrogel layer directly below the electrode elements, resulting in hot spots directly below the electrode elements.

[0059] In contrast, FIG. 6B shows the current distribution for the embodiment of FIG. 6A. As shown in FIG. 6B, the current is still distributed only in the area under the electrode elements in the top hydrogel layer. However, the sheet of anisotropic material spreads the heat across its area because its thermal conductivity in the horizontal direction (i.e., parallel to the plane of the sheet) is much higher than its thermal conductivity in the vertical direction. In addition to spreading the heat, the low electrical resistance of the sheet in the horizontal direction spreads the current outward across the sheet, and this diffuse current distribution persists in the skin contact layer of the conductive adhesive from there to the subject's skin. In this embodiment, hot spots are eliminated (or at least minimized) because both the current and the heat are spread over a larger area of ​​the skin contact layer of the conductive adhesive 110. This means that for a given applied AC voltage, the hottest point under the electrode assembly of the embodiment of FIG. 6A / B is lower than the hottest point under the electrode assembly of the prior art embodiment of FIG. 1. Thus, the current may be increased (relative to the prior art current) without exceeding a safe temperature threshold at any point under the electrode assembly of the embodiment of FIG. 6A. This increased current is advantageous in increasing the effectiveness of TT field therapy. Similar results can be achieved when the hydrogel is replaced with a conductive adhesive, such as the conductive adhesive composites disclosed herein.

[0060] FIG. 7 is a cross-sectional view along the dashed line of FIG. 5 of a second embodiment of an electrode assembly 100 including electrode elements E1 and E2. The embodiment of FIG. 7 is similar in all respects to the embodiment of FIG. 6A, except as follows: The embodiment of FIG. 6A includes a large continuous layer of conductive material 138 (e.g., hydrogel or conductive adhesive composite) disposed between the sheet of anisotropic material and the front faces of both the first and second electrode elements E1 and E2. In contrast, the embodiment of FIG. 7 includes discrete regions of conductive material 138 for each electrode element. Thus, the embodiment of FIG. 7 includes a first layer of conductive material 138 located between the first front face of the first electrode element E1 and the rear face of the sheet 130, and also includes a second layer of conductive material 138 located between the second front face of the second electrode element E2 and the rear face of the sheet. The first and second layers of conductive material facilitate electrical contact between the front face of each electrode and the rear face of the sheet 130. (FIG. 7 shows electrodes E1 and E2 with a metal backing layer (diagonal hatching) and a dielectric layer 160, similar to FIG. 6A.) In some embodiments, the layer of conductive material 138 may be a layer of hydrogel, although alternative embodiments may use a different conductive material (e.g., conductive grease, conductive adhesive, conductive tape, etc.). For example, the layer of conductive material may be a layer of a conductive adhesive composite disclosed herein.

[0061] In some embodiments, the skin contact layer 110 may include a conductive adhesive 112 (FIG. 7), such as the conductive adhesive composites described herein. In further embodiments, the skin contact layer 110 may include a hydrogel.

[0062] As with the embodiment of FIG. 6A, in the embodiment of FIG. 7, the current in the embodiment of FIG. 7 is still concentrated only in the top layer of conductive material in the area under the electrode elements. The sheet of anisotropic material 130 distributes the heat and current as described above in connection with the embodiment of FIG. 6A, eliminating or at least minimizing hot spots. This means that for a given applied AC voltage, the hottest point under the electrode assembly of the embodiment of FIG. 7 is lower than the hottest point under the electrode assembly of the prior art embodiment of FIG. 1. Thus, the current may be increased (relative to the prior art current) without exceeding a safe temperature threshold at any point under the electrode assembly of the embodiment of FIG. 5. This increase in current is then advantageous in increasing the effectiveness of the TT field treatment.

[0063] FIG. 2 is a cross-sectional view of a third embodiment of an electrode assembly including a single electrode element. In the embodiment of FIG. 2, as described above, the electrode assembly includes a sheet of anisotropic material 130 having a front surface (toward the subject's skin in FIG. 2) and a rear surface. This sheet is similar to the sheet described in FIG. 6A. In some embodiments, the sheet of anisotropic material is a sheet of pyrolytic graphite. In other embodiments, the sheet of anisotropic material is a graphite foil made of compressed high-purity exfoliated mineral graphite. In other embodiments, the sheet of anisotropic material is a graphitized polymer film, such as a graphitized polyimide film. In other embodiments, the sheet of anisotropic material is a sheet of pyrolytic carbon. In other embodiments, the sheet of anisotropic material is a sheet of other conductive anisotropic materials. The embodiment of FIG. 2 also shows a layer of conductive material 138. The beneficial effects of heat and current dispersion discussed above in connection with the embodiment of FIG. 6A, which eliminates or at least minimizes hot spots, are similarly realized in this third embodiment. This means that for a given applied AC voltage, the hottest point under the electrode assembly of the embodiment of Figure 2 is lower than the hottest point under the electrode assembly of the prior art embodiment of Figure 1. Thus, the current may be increased (relative to the prior art current) without exceeding a safe temperature threshold at any point under the electrode assembly of the embodiment of Figure 2. And this increased current is advantageous in increasing the effectiveness of the TT field therapy.

[0064] Figure 8 is a cross-sectional view of a fourth embodiment of an electrode assembly including a single electrode element E1. The embodiment of Figure 8 is similar to the embodiment of Figure 6, except that the first front surface of the first electrode element E1 is the front surface of a metal strip (indicated by diagonal hatching) and is located in direct contact with the rear surface of the anisotropic sheet of material 130 (which includes a dielectric layer 160 and is electrically connected via an intervening layer of conductive material 138).

[0065] As with the embodiment of FIG. 2, the anisotropic material sheet 130 of the embodiment of FIG. 8 distributes heat and current as described above in connection with the embodiment of FIG. 6A, eliminating or at least minimizing hot spots. This means that for a given applied AC voltage, the hottest point under the electrode assembly of the embodiment of FIG. 8 is lower than the hottest point under the electrode assembly of the prior art embodiment of FIG. 1. Thus, the current may be increased (relative to the prior art current) without exceeding a safe temperature threshold at any point under the electrode assembly of the embodiment of FIG. 8. This increase in current is then advantageous in increasing the effectiveness of the TT field treatment.

[0066] In some embodiments, the skin contact layer 110 may include a conductive adhesive 112 (FIG. 8), such as the conductive adhesive composites described herein. In further embodiments, the skin contact layer 110 may include a hydrogel.

[0067] In some embodiments, a capacitor may be connected in series with and behind the metal strip.

[0068] Figure 9 illustrates a method of applying an alternating electric field to a target area within a subject's body using a pair of electrode assemblies of Figure 6A. (Any of the electrode assemblies described above in connection with Figures 2-8 can be used.)

[0069] A method of applying a TT field includes positioning a first electrode assembly at a first location on or within the subject's body (in the example shown in FIG. 9 , the first electrode assembly is located on the subject's skin on the right side of the subject's head facing the target area, e.g., the tumor).

[0070] The method further includes positioning a second electrode assembly at a second location in or on the subject's body (in the example shown in FIG. 9 , the second electrode assembly is located on the subject's skin on the left side of the subject's head facing the target area).

[0071] The method further includes applying an alternating voltage between the first electrode assembly and the second electrode assembly after positioning the first electrode assembly and the second electrode assembly.

[0072] The AC voltage between the first and second electrode assemblies may be applied by an AC voltage generator 820. In some embodiments, the frequency of the AC voltage is between 50 kHz and 1 MHz, or between 100 kHz and 500 kHz. In the illustrated example, the AC voltage generator is controlled by a controller 822. The controller 822 can control the amplitude of the current delivered through the first and second electrode assemblies 100 with the temperature measurements to maintain a temperature below a safety threshold (e.g., 41° C.). This can be accomplished, for example, by measuring a first temperature of the first electrode element, measuring a second temperature of the second electrode element, and controlling the application of the AC voltage based on the first and second temperatures, as described below.

[0073] FIG. 9 shows an example of suitable hardware for this purpose. More specifically, a temperature sensor 800 (e.g., a thermistor) is disposed in thermal contact with each electrode element (e.g., dielectric material 310 / metal layer 320) in each electrode assembly 100. The temperature sensor 800 measures corresponding first and second temperatures (e.g., the first and second electrode elements of the first and second electrode assemblies, respectively), and a controller 822 controls the output of an AC voltage generator 820 based on these temperatures. FIG. 9 also shows the skin contact layer 110, which includes a conductive adhesive 112, the layer of anisotropic material 130, and the layer of conductive material 138 that resides between the electrode elements 310 / 320 and the layer of anisotropic material 130.

[0074] As discussed above, it is contemplated that one or more of the layers of conductive material disclosed herein (e.g., layers 110, 138 including conductive adhesive 112) may comprise a conductive adhesive composite (described further below) rather than a hydrogel. In an exemplary aspect, the conductive adhesive composite may comprise a dielectric material and conductive particles dispersed within the dielectric material. In some embodiments, at least a portion of the conductive particles may define a conductive path through the thickness of the conductive adhesive composite. It is believed that the conductive particles may be aligned in response to application of an electric field such that the conductive particles undergo electrophoresis. In some aspects, the dielectric material of the electrode assembly may be a polymer adhesive. Optionally, in these aspects, the polymer adhesive may be an acrylic adhesive. In some aspects, the conductive particles may comprise carbon. Optionally, in these aspects, the conductive particles may comprise graphite powder. Alternatively or additionally, the conductive particles may comprise carbon flakes. Alternatively or additionally, the conductive particles may comprise carbon particles. Alternatively or additionally, the conductive particles may comprise carbon fibers. Alternatively or additionally, the conductive particles may include carbon nanotubes. Alternatively or additionally, the conductive particles may include carbon nanowires. Alternatively or additionally, the conductive particles may include carbon black powder. Alternatively or additionally, the conductive particles may include carbon microcoils. The conductive particles may be a combination of types of particles. In a further aspect, the conductive adhesive composite further includes a polar material (e.g., a polar salt). Polar salts include quaternary ammonium salts, such as tetraalkylammonium salts. Exemplary conductive adhesive composites and methods of making such conductive adhesive composites are disclosed in U.S. Pat. No. 8,673,184 and U.S. Pat. No. 9,947,432, which are incorporated herein by reference for all purposes.The conductive adhesive composite may be, for example, a dry carbon / salt adhesive such as the OMNI-WAVE adhesive composition manufactured and sold by Flexcon® (Spencer, Massachusetts, USA) or the ARcare® 8006 conductive adhesive composition manufactured and sold by Adhesives Research, Inc. (Glen Rock, Pennsylvania, USA).

[0075] In exemplary embodiments, it is contemplated that by using a conductive adhesive composite as the skin contact layer as disclosed herein, additional backing and / or cover layers (such as, for example, adhesive backing 55) may be omitted. In these embodiments, the conductive adhesive composite may provide sufficient adhesion to the skin such that additional layers are not required to maintain the desired position of the electrode assembly on the subject's body, thereby reducing ease of use and overall cost of manufacture and use.

[0076] In a further aspect, by avoiding the use of hydrogels in the electrode assembly, it is believed that the electrode assembly including the conductive adhesive composite as disclosed herein does not require moisture-proof packaging, thereby making packaging costs much more affordable.In addition, it is believed that the conductive adhesive composite of the disclosed electrode assembly can avoid the signal fluctuation problem of hydrogels, thereby providing consistent material properties (e.g., adhesion) and reliable performance during the delivery of TT fields.Furthermore, it is believed that the disclosed conductive adhesive composite has a much longer shelf life than hydrogels, thereby reducing the frequency with which the electrode assembly (or the skin contact layer of the electrode assembly) must be replaced.

[0077] Exemplary Aspects Below, more specifically described aspects of the present invention are described in terms of products, systems, methods and variations thereof. However, these specifically recited aspects should not be construed to have any limiting effect on the different claims that include different or more general teachings set forth herein, or to be construed in any way other than the inherent meaning of the language in which the "specific" aspect is literally used.

[0078] Aspect 1: An apparatus comprising: a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface; a skin contact layer comprising a conductive adhesive, the skin contact layer coupled to the subassembly and disposed on a skin-facing side of the at least one electrode element, the skin contact layer electrically coupled to the electrode and configured to contact the skin of a subject, at least a portion of the skin contact layer being selectively removable from the subassembly.

[0079] Aspect 2: The device of aspect 1, further comprising a first adhesive bonding the skin contact layer to the subassembly.

[0080] Aspect 3: The device of any one of the preceding aspects, comprising a plurality of layers including a conductive adhesive, the plurality of layers including an outermost layer forming the skin contact layer and at least one intermediate layer disposed between the at least one electrode element and the skin contact layer, the skin contact layer being bonded to the at least one intermediate layer, and the skin contact layer being configured to be separated from the at least one intermediate layer.

[0081] Aspect 4: The device of Aspect 3, wherein the at least one intermediate layer is configured to form an outermost skin contact layer when the skin contact layer is separated from the at least one intermediate layer.

[0082] Aspect 5: The device of Aspect 4, wherein the at least one intermediate layer includes multiple intermediate layers that sequentially form the outermost skin contact layer when an outermost layer of each adjacent conductive adhesive of the multiple conductive adhesives is separated from the subassembly.

[0083] Aspect 6: A device described in any one of the preceding aspects, wherein the subassembly further includes a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the skin contact layer being disposed on the skin-facing side of the layer of anisotropic material.

[0084] Example 7: The device of any one of the previous examples, wherein the skin contact layer comprises a conductive adhesive composite.

[0085] Aspect 8: A method comprising: 1. A method comprising: bonding a skin contact layer comprising a conductive adhesive to a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface, the skin contact layer being adapted to be disposed on the skin-facing side of the at least one electrode element.

[0086] Aspect 9: The method of aspect 8, wherein the subassembly further includes an existing skin contact layer, and wherein bonding the skin contact layer to the subassembly includes bonding the skin contact layer to the existing skin contact layer.

[0087] Aspect 10: The method of aspect 8, wherein the subassembly further includes an existing skin contact layer, and further comprising the step of removing the existing skin contact layer from the subassembly prior to bonding the skin contact layer to the subassembly.

[0088] Example 11: The method of Example 8, wherein the subassembly further comprises a first adhesive bonding the skin contact layer to the subassembly.

[0089] Aspect 12: A method according to any one of aspects 8 to 11, wherein the subassembly further includes a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the bonding includes bonding the skin contact layer to the subassembly such that the skin contact layer is positioned on the skin-facing side of the layer of anisotropic material.

[0090] Aspect 13: The method of aspect 12, wherein each of the layer of anisotropic material and the skin contact layer defines a corresponding perimeter, and further comprising a step of trimming the perimeter of the skin contact layer in alignment with the perimeter of the layer of anisotropic material.

[0091] Aspect 14: The method of any one of aspects 8 to 13, wherein the skin contact layer comprises a conductive adhesive composite.

[0092] Example 15: The method of any one of Examples 9 to 14, wherein the existing skin contact layer comprises a conductive adhesive composite.

[0093] Aspect 16: A method comprising: removing the skin contact layer from the assembly, said assembly comprising: at least one electrode element having a skin-facing surface; and a plurality of conductive adhesive layers, the plurality of conductive adhesive layers comprising: an outermost conductive adhesive layer defining said skin contact layer; at least one intermediate layer disposed between the at least one electrode element and the skin contact layer; The method, wherein the step of removing the skin contact layer from the assembly includes removing the skin contact layer from the at least one intermediate layer to expose the at least one intermediate layer and define a new skin contact layer.

[0094] Aspect 17: The method of aspect 16, wherein the at least one intermediate layer includes multiple intermediate layers that sequentially form the outermost skin contact layer when an outermost layer of each adjacent conductive adhesive of the multiple conductive adhesives is separated from the assembly.

[0095] Aspect 18: A method according to any one of Aspects 16 to 17, wherein the assembly further includes a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the skin contact layer being positioned on the skin-facing side of the layer of anisotropic material.

[0096] Aspect 19: The method of any one of aspects 16 to 18, wherein the skin contact layer comprises a conductive adhesive composite.

[0097] Aspect 20: The method of any one of aspects 16 to 19, further comprising, following the step of removing the skin contact layer from the assembly, adding a new skin contact layer comprising a conductive adhesive composite.

[0098] Embodiment 21: The device of any one of embodiments 1 to 7, wherein the skin contact layer comprises a hydrogel.

[0099] Aspect 22: The method of aspect 16, wherein the at least one intermediate layer is configured to form an outermost skin contact layer upon removal of the skin contact layer from the at least one intermediate layer.

[0100] Aspect 23: The method of any one of aspects 16 to 18, wherein each of the plurality of conductive adhesive layers comprises a conductive adhesive composite.

[0101] Aspect 24: The device of Aspect 7, wherein the conductive adhesive composite comprises a dielectric material and conductive particles dispersed within the dielectric material, the conductive particles comprising carbon flakes, carbon granules, carbon fibers, carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon black powder, graphite powder, carbon nanowires, carbon microcoils, or any combination thereof.

[0102] Aspect 25: The method of aspect 14 or aspect 15, wherein the conductive adhesive composite comprises a dielectric material and conductive particles dispersed within the dielectric material, the conductive particles comprising carbon flakes, carbon granules, carbon fibers, carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon black powder, graphite powder, carbon nanowires, carbon microcoils, or any combination thereof.

[0103] Aspect 26: The method of any one of aspects 19, 20, or 23, wherein the conductive adhesive composite comprises a dielectric material and conductive particles dispersed within the dielectric material, the conductive particles comprising carbon flakes, carbon granules, carbon fibers, carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon black powder, graphite powder, carbon nanowires, carbon microcoils, or any combination thereof.

[0104] Embodiment 27: The method of any one of embodiments 9 to 15, wherein the skin contact layer is part of a two-layer unit or a three-layer unit, the two-layer unit including a layer of anisotropic material and a skin contact layer, and the three-layer unit including a layer of conductive material, a layer of anisotropic material, and a skin contact layer.

[0105] Aspect 27: A method according to any one of aspects 18 to 20, wherein the step of removing the skin contact layer from the assembly includes removing the two-layer unit or the three-layer unit from the assembly, the two-layer unit including a layer of anisotropic material and a skin contact layer, and the three-layer unit including a layer of conductive material, a layer of anisotropic material, and a skin contact layer.

[0106] Embodiment 28: A kit comprising: A kit comprising a plurality of replaceable units comprising a layer of anisotropic material and a skin contact layer bonded to said anisotropic layer.

[0107] Embodiment 29: The kit described in embodiment 28, wherein the unit is a two-layer unit comprising a layer of anisotropic material and the skin contact layer.

[0108] Aspect 30: The unit is a three-layer unit including a layer of anisotropic material, the skin contact layer, and a layer of conductive material, the layer of anisotropic material being disposed between the skin contact layer and the layer of conductive material; 29. The kit of embodiment 28, wherein the skin contact layer is part of a bilayer unit or a trilayer unit, the bilayer unit comprising a layer of anisotropic material and a skin contact layer, and the trilayer unit comprising a layer of conductive material, a layer of anisotropic material, and a skin contact layer.

[0109] Aspect 31: A method comprising: 1. A method comprising: bonding a skin contact layer comprising a conductive adhesive to a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface, the skin contact layer being adapted to be disposed on the skin-facing side of the at least one electrode element, the skin contact layer having an in-plane conductivity and a conductivity perpendicular to the in-plane conductivity, the in-plane conductivity being substantially equal to the conductivity perpendicular to the in-plane conductivity.

[0110] Aspect 32: A method comprising a step of bonding a skin contact layer comprising a conductive adhesive to a subassembly comprising at least one electrode element having a skin-facing side and a skin-facing surface, the skin contact layer being positioned on the skin-facing side of the at least one electrode element, the skin contact layer having an in-plane conductivity and a conductivity perpendicular to the in-plane conductivity, the in-plane conductivity being at least two times greater than the conductivity perpendicular to the in-plane conductivity.

[0111] Although the present invention has been disclosed with reference to certain embodiments, many modifications, variations and variations of the described embodiments are possible without departing from the field and scope of the invention, as defined in the appended claims. Thus, the present invention is not limited to the described embodiments, but has the full scope defined by the language of the following claims and equivalents thereof. [Explanation of symbols]

[0112] 40 Electrode Assembly 55 Flexible self-adhesive backing 90 Lead 100 Apparatus, electrode assembly 102 Subassembly 104 Electrode Element 106 Skin side 108 Skin-facing surface 110 Skin contact layer 112 Conductive adhesive 114 First Adhesive 120 Multiple Layers 122 Middle Class 130 Layer of anisotropic material 132 Skin side 134 Skin-facing surface 136 Outward Facing Surface 138 Layer of conductive material 140 Existing skin contact layer 150 Periphery 152 Periphery 160 Dielectric layer 310 Dielectric Materials 320 metal layer 800 Temperature Sensor 820 AC voltage generator 822 Controller E1 1st electrode element E2 2nd electrode element X1, X2, X3, X4, X5, X6, X7, X8, X9 electrode elements

Claims

1. 1. An apparatus comprising: a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface; a skin contact layer coupled to the subassembly and positioned on a skin-facing side of the at least one electrode element, the skin contact layer being electrically coupled to the at least one electrode element and configured to contact the skin of a subject, at least a portion of the skin contact layer being selectively removable from the subassembly.

2. The device of claim 1 further comprising a first adhesive bonding the skin contact layer to the subassembly.

3. The device described in claim 1, wherein the device includes a plurality of layers, the plurality of layers including an outermost layer forming the skin contact layer and at least one intermediate layer arranged between the at least one electrode element and the skin contact layer, the skin contact layer being bonded to the at least one intermediate layer, and the skin contact layer being configured to be detached from the at least one intermediate layer.

4. The device of claim 3 , wherein the at least one intermediate layer is configured to form an outermost skin-contacting layer upon separation of the skin-contacting layer from the at least one intermediate layer.

5. 10. The device of claim 1, wherein the subassembly further includes a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the skin-contact layer being disposed on the skin-facing side of the layer of anisotropic material.

6. 1. A method comprising:

1. A method comprising: bonding a skin contact layer comprising a conductive adhesive to a subassembly including at least one electrode element having a skin-facing side and a skin-facing surface, the skin contact layer being adapted to be disposed on the skin-facing side of the at least one electrode element.

7. 7. The method of claim 6, wherein the subassembly further comprises a pre-existing skin contact layer, and wherein bonding the skin contact layer to the subassembly comprises bonding the skin contact layer to the pre-existing skin contact layer.

8. 7. The method of claim 6, wherein the subassembly further comprises a pre-existing skin contact layer, and further comprising removing the pre-existing skin contact layer from the subassembly prior to bonding the skin contact layer to the subassembly.

9. 7. The method of claim 6, wherein the subassembly further includes a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the bonding includes bonding the skin-contact layer to the subassembly such that the skin-contact layer is disposed on the skin-facing side of the layer of anisotropic material.

10. 7. The method of claim 6, wherein the skin contact layer is part of a two-layer unit or a three-layer unit, the two-layer unit including a layer of anisotropic material and a skin contact layer, and the three-layer unit including a layer of conductive material, a layer of anisotropic material, and a skin contact layer.

11. 1. A method comprising: removing the skin contact layer from the assembly, said assembly comprising: at least one electrode element having a skin-facing surface; a plurality of conductive adhesive layers, the plurality of conductive adhesive layers comprising: an outermost conductive adhesive layer defining the skin contact layer; at least one intermediate layer disposed between the at least one electrode element and the skin contact layer; The method, wherein the step of removing the skin contact layer from the assembly includes removing the skin contact layer from the at least one intermediate layer to expose the at least one intermediate layer and define a first new skin contact layer.

12. 12. The method of claim 11 , wherein the at least one intermediate layer comprises a plurality of intermediate layers that sequentially form the outermost skin-contacting layer when an outermost layer of each adjacent conductive adhesive of the plurality of conductive adhesives is separated from the assembly.

13. 12. The method of claim 11, wherein the assembly further comprises a layer of anisotropic material having a skin-facing side and an opposite outward-facing side, the at least one electrode element being in electrical contact with the outward-facing side of the layer of anisotropic material, and the skin contact layer being disposed on the skin-facing side of the layer of anisotropic material.

14. 12. The method of claim 11, further comprising the step of adding a second new skin contact layer comprising a conductive adhesive composition following the step of removing the skin contact layer from the assembly.

15. 13. The method of claim 12, wherein the step of removing the skin contact layer from the assembly comprises removing a two-layer unit or a three-layer unit from the assembly, the two-layer unit comprising a layer of anisotropic material and a skin contact layer, and the three-layer unit comprising a layer of conductive material, a layer of anisotropic material, and a skin contact layer.

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