MEDICAL DEVICE AND METHOD FOR MANUFACTURING A PRODUCT, IN PARTICULAR A MEDICAL DEVICE

Description

SCOPE OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a medical device and a method for manufacturing a medical device.

[0002] Due to the high and still increasing incidence of arteriosclerotic diseases, advanced intraoperative diagnostic and therapeutic approaches are of fundamentally great social and economic importance. The digitalization of regulated medical applications requires a secure database and thus complementary and independent methods for obtaining information. Various, and sometimes redundant, sensors contribute to this. Currently used methods for arteriosclerotic diseases, such as imaging techniques (contrast angiography, Doppler, and intravascular ultrasound) for assessing the severity of pathological vascular changes, are limited to analyzing vessel diameter and thus the degree of stenosis.Treatment decisions can be improved through more precise differentiation, but this requires additional information about the mechanical properties of the vessel walls. While modern and complex intravascular ultrasound systems are used, particularly in studies, to gain insights into the local vascular structure, simple sensor solutions that could be used in routine clinical practice and, in particular, close the information gap regarding mechanical tissue properties, are not yet commercially available.

[0003] An implantable, wireless sensor for monitoring blood pressure is known, wherein the sensor has a flexible substrate made of parylene, a copper layer, a chromium / gold layer and a PDMS layer (Lo Shao-Hsiang et al.: "A Wireless Parylene-Based Cardiovascular Pressure Sensor with Mxene Film", 2019 20TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS & EUROSENSORS XXXIII (TRANSDUCERS & EUROSENSORS XXXIII)).

[0004] US patent 2003 / 028210 A1 discloses a metallic balloon catheter whose balloon may be coated with a biocompatible elastomer to protect the balloon from splintering in the event of metal fatigue and / or cracking.

[0005] The subject of US 2017 / 119450 A1 is a balloon catheter capable of increasing the temperature of a blood vessel, comprising, among other things, a guide wire tube, an inner tube, an outer tube, a heat-generating element, a light guide element, and a cover tube superimposed radially on the heat-generating element, onto which a light-reflecting metal layer is laminated.

[0006] Furthermore, a piezoresistive touch sensor based on a polymer film with microcracks is known, wherein the cracks are formed by the self-tension of a metal layer sputtered onto the polymer film (PDMS film) and Ti 3 C 2 is embedded in the cracks of the touch sensor as sensor material (CHEN LONGLONG ET AL: "High-Tactile Sensitivity of Piezoresistive Sensors With a Micro-Crack Structure Induced by Thin Film Tension", IEEE ELECTRON DEVICE LETTERS, IEEE, USA, Vol. 40, No. 9, September 1, 2019 (2019-09-01), pages 1519-1521). TASK AND SOLUTION

[0007] The object of the invention is to provide a medical device and a method for manufacturing a medical device, which in particular address the market gap mentioned in the introduction.

[0008] This problem is solved by a medical device having the features according to independent claim 1 and by a method for manufacturing a medical device according to claim 12. Preferred embodiments of the invention are the subject of the dependent claims and the following description. The wording of all claims is hereby incorporated by express reference into the description.

[0009] According to a first aspect, the invention relates to a medical device in the form of a balloon catheter.

[0010] The medical device has at least one multi-layer structure, which includes or consists of the following superimposed layers: at least one metal layer and at least one elastomer material layer.

[0011] The expression "at least one multilayer structure" can, within the meaning of the present invention, mean either one multilayer structure or a plurality of multilayer structures, i.e., two or more multilayer structures.

[0012] The multilayer structure, as defined in the present invention, can be designed in particular as a laminate- and / or membrane-like structure, especially a metal-polymer laminate composite, preferably a metal-polymer laminate membrane. Furthermore, the multilayer structure, as defined in the present invention, can be described in particular as a metal-polymer multilayer composite structure, especially a metal-polymer two-layer composite structure.

[0013] The expression "at least one metal layer" can, within the meaning of the present invention, mean either one metal layer or a plurality of metal layers, i.e., two or more metal layers.

[0014] For the purposes of the present invention, the term "metal layer" means a layer comprising or consisting of at least one metal, in particular in elemental form or in the form of an alloy.

[0015] The expression "at least one elastomeric material layer" can, within the meaning of the present invention, mean either one elastomeric material layer or a plurality of elastomeric material layers, i.e., two or more elastomeric material layers.

[0016] For the purposes of the present invention, the term "elastomeric material layer" means a layer comprising at least one elastomeric material, in particular at least one elastomer, preferably at least one hyperelastic polymer, or consisting of at least one elastomeric material, in particular at least one elastomer, preferably at least one hyperelastic polymer.

[0017] For the purposes of the present invention, the term "hyperelastic polymer" shall be understood to mean a polymer, in particular an elastomer, with hyperelastic properties, especially high reversible elongation.

[0018] The at least one metal layer preferably has a varying surface morphology. The varying surface morphology is preferably designed to influence, in particular to increase or decrease, the sensitivity, especially the resistive behavior, to mechanical stress, especially strain.

[0019] The invention is based in particular on the surprising finding that the multilayer structure provided according to the invention can be used as a sensor unit in medicine, in particular for determining tissue elasticity, preferably the elasticity of hollow organs, such as blood vessels.

[0020] In an embodiment of the invention, the at least one elastomeric material layer comprises at least one elastomeric material, in particular a hyperelastic material, or consists of an elastomeric material, in particular a hyperelastic material, selected from the group consisting of elastomers, thermoplastic elastomers, thermoplastic polyamide elastomers, thermoplastic copolyester elastomers, thermoplastic olefin-based elastomers, thermoplastic styrene block copolymers, thermoplastic urethane-based elastomers, thermoplastic olefin-based vulcanizates, cross-linked thermoplastic olefin-based elastomers, vulcanizates of natural rubbers, vulcanizates of synthetic rubbers, styrene-butadiene rubber, butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), ethylene propylene diene monomer rubber (EPDM), chloroprene rubber (CR). Polyisoprene rubber (IR), polyalkylsiloxanes, polydimethylsiloxane, silicone rubbers, silicone elastomers,Methyl silicone, vinyl methyl silicone, phenyl vinyl methyl silicone, phenyl-modified silicone, fluoroalkyl silicone, fluorovinyl methyl silicone and mixtures of at least two of the aforementioned elastomeric materials.

[0021] Preferably, at least one elastomer material layer comprises a polyalkylsiloxane, in particular polydimethylsiloxane, or consists of polyalkylsiloxane, in particular polydimethylsiloxane.

[0022] Furthermore, at least one elastomer material layer can be designed in a foil-like form.

[0023] In particular, the at least one elastomeric material layer can be formed, especially directly or not directly, on a surface, especially an outer and / or inner surface, preferably an outer surface, of the medical device.

[0024] In a further embodiment of the invention, the at least one elastomer material layer has a layer thickness of 0.0001 mm to 0.2 mm, in particular 0.0005 mm to 0.1 mm, preferably 0.001 mm to 0.05 mm.

[0025] In a further embodiment of the invention, the at least one metal layer comprises at least one metal, in particular in elemental form or in the form of an alloy, or consists of at least one metal, in particular in elemental form or in the form of an alloy, which is selected from the group consisting of gold, platinum, indium, tin, copper, silver, gallium and mixtures, in particular alloys, of at least two of the aforementioned metals.

[0026] Furthermore, at least one metal layer can be designed in a foil-like form.

[0027] Furthermore, the at least one metal layer can be designed in a serpentine shape, at least in sections or areas, in particular only in sections or areas or continuously, or cover or coat the at least one elastomeric material layer.

[0028] Preferably, the thickness of the at least one metal layer is less than the thickness of the at least one elastomer material layer.

[0029] In a further embodiment of the invention, the at least one metal layer has a layer thickness of ≤ 150 nm, in particular 10 nm to 100 nm, preferably 40 nm to 80 nm.

[0030] In a further embodiment of the invention, the at least one elastomeric material layer is covered or coated by the at least one metal layer, in particular directly or indirectly. Furthermore, the at least one elastomeric material layer can be completely covered or coated by the at least one metal layer, i.e., continuously or over the entire surface, or only partially covered or coated, i.e., section by section or area. Preferably, however, the at least one elastomeric material layer is only partially covered or coated by the at least one metal layer. Particularly preferred is the at least one elastomeric material layer being covered or coated by the at least one metal layer directly and only section by section or area.

[0031] In a further embodiment of the invention, at least one adhesion layer is arranged or formed between the at least one metal layer and the at least one elastomer material layer.

[0032] The expression "at least one adhesion layer" can, within the meaning of the present invention, mean either one adhesion layer or a plurality of adhesion layers, i.e., two or more adhesion layers.

[0033] For the purposes of the present invention, the term "adhesion layer" means a layer comprising or consisting of at least one material which is capable of enabling and / or improving the adhesion of the at least one metal layer to the at least one elastomer material layer.

[0034] Furthermore, the at least one adhesive layer can directly or indirectly cover or coat the at least one elastomeric material layer. In particular, the at least one adhesive layer can completely cover or coat the at least one elastomeric material layer, i.e., continuously or over the entire surface, or only partially, i.e., section by section or area. Preferably, however, the at least one adhesive layer only partially covers the at least one elastomeric material layer.

[0035] Furthermore, the at least one metal layer can directly or indirectly cover or coat the at least one adhesive layer. In particular, the at least one metal layer can completely cover or coat the at least one adhesive layer, i.e., continuously or over the entire surface, or only partially, i.e., section by section or area. Preferably, however, the at least one metal layer completely covers the at least one adhesive layer.

[0036] In a further embodiment of the invention, the at least one adhesion layer is covered or coated, in particular directly and preferably completely, by the at least one metal layer, and the at least one elastomer material layer is covered or coated, in particular directly and preferably only sectionally or in areas, by the at least one adhesion layer.

[0037] In a further embodiment of the invention, the at least one adhesion layer comprises at least one material or consists of at least one material selected from the group consisting of titanium, aluminum, chromium and mixtures of at least two of the aforementioned materials.

[0038] Furthermore, at least one adhesion layer can be designed in a foil-like form.

[0039] Furthermore, the at least one adhesion layer can be designed in a serpentine shape, at least in sections or areas, in particular only in sections or areas or continuously, or cover or coat the at least one elastomeric material layer.

[0040] Preferably, the thickness of the at least one adhesion layer is less than the thickness of the at least one elastomer material layer.

[0041] In particular, the thickness of the at least one adhesion layer can be less than the thickness of the at least one metal layer.

[0042] Preferably, the at least one adhesion layer has a layer thickness ≤ 20 nm, in particular 3 nm to 20 nm, preferably 4 nm to 10 nm.

[0043] In a further embodiment of the invention, the at least one metal layer and / or the at least one adhesive layer are configured as a conductor track(s). The conductor track(s) are designed to derive an electrical measurement signal. For the evaluation of the electrical measurement signal, the at least one metal layer and / or the at least one adhesive layer can, in this embodiment of the invention, be electrically connected or contactable with an evaluation unit for evaluating the electrical measurement signal.

[0044] In a further embodiment of the invention, the at least one multilayer structure further comprises at least one additional elastomeric material layer, i.e., only one additional elastomeric material layer or a plurality of, i.e., two or more, elastomeric material layers. Preferably, the at least one metal layer is covered or coated, in particular directly or indirectly, preferably directly, by the at least one additional elastomeric material layer.

[0045] Preferably, the thickness of the at least one metal layer is less than the thickness of the at least one additional elastomer material layer.

[0046] Preferably, the thickness of the at least one adhesion layer is less than the thickness of the at least one additional elastomer material layer.

[0047] The at least one additional elastomer material layer can have a layer thickness of 0.001 mm to 0.15 mm, in particular 0.001 mm to 0.1 mm, preferably 0.001 mm to 0.05 mm.

[0048] Furthermore, at least one additional elastomer material layer can be designed in a foil-like form.

[0049] Furthermore, the at least one additional elastomer material layer and the at least one elastomer material layer can be designed the same or differently, in particular with regard to the elastomer material and / or the layer thickness.

[0050] Furthermore, the at least one additional elastomer material layer, in particular independent of the at least one elastomer material layer, can comprise an elastomer material, in particular a hyperelastic material, or consist of an elastomer material, in particular a hyperelastic material, selected from the group consisting of elastomers, thermoplastic elastomers, thermoplastic polyamide elastomers, thermoplastic copolyester elastomers, thermoplastic olefin-based elastomers, thermoplastic styrene block copolymers, thermoplastic urethane-based elastomers, thermoplastic olefin-based vulcanizates, cross-linked thermoplastic olefin-based elastomers, vulcanizates of natural rubbers, vulcanizates of synthetic rubbers, styrene-butadiene rubber, butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), ethylene propylene diene monomer rubber (EPDM). Chloroprene rubber (CR), polyisoprene rubber (IR), polyalkylsiloxanes,Polydimethylsiloxane, silicone rubbers, silicone elastomers, methyl silicone, vinyl methyl silicone, phenyl vinyl methyl silicone, phenyl-modified silicone, fluoroalkyl silicone, fluorovinyl methyl silicone and mixtures of at least two of the aforementioned elastomeric materials.

[0051] Preferably, the at least one additional elastomer material layer comprises a polyalkylsiloxane, in particular polydimethylsiloxane, or consists of polyalkylsiloxane, in particular polydimethylsiloxane.

[0052] In a further embodiment of the invention, the at least one multilayer structure or the at least one metal layer has a varying surface morphology. In particular, the at least one multilayer structure or the at least one metal layer can have corrugated surface areas and / or non-corrugated surface areas. Preferably, the at least one multilayer structure or the at least one metal layer has surface areas, in particular corrugated surface areas and / or non-corrugated surface areas, with cracks, in particular microcracks, and / or surface areas, in particular corrugated surface areas and / or non-corrugated surface areas, without cracks. Particularly preferably, the at least one multilayer structure or the at least one metal layer has, in particular, corrugated and / or non-corrugated surface areas with cracks, in particular microcracks, and corrugated surface areas without cracks.By varying the surface morphology, the sensitivity of at least one metal layer to mechanical stress, in particular strain, can advantageously be influenced selectively, in particular increased or decreased.

[0053] For the purposes of the present invention, the term "microcracks" shall be understood to mean cracks that have at least one dimension, in particular selected from the group consisting of length, width, depth and combinations of at least two of the aforementioned dimensions, in the micrometer and / or nanometer range, in particular in a range of 1 nm to 5 µm, in particular 10 nm to 2 µm, preferably 20 nm to 1 µm. The formation of the cracks is preferably dependent on the coating parameters applied and / or a pretreatment of the surface of the at least one elastomer material layer.

[0054] For the purposes of the present invention, the term "wavy surface areas without cracks" is understood to mean, preferably, periodically repeating wave-like deformations of the surface of the at least one metal layer, arising from compressive stress within the at least one metal layer, and in particular from deformation of the underlying at least one elastomeric material layer. Preferably, the wavy surface areas without cracks have at least one dimension, in particular selected from the group consisting of period length and amplitude and combinations of the two aforementioned dimensions, in the micrometer and / or nanometer range, in particular in a range of 10 nm to 15 µm, more specifically 20 nm to 10 µm, and preferably 40 nm to 6 µm.

[0055] In a further embodiment of the invention, the at least one multilayer structure is part of a surface, in particular an outer and / or inner surface, of the medical device. In particular, the medical device, especially an outer and / or inner surface of the medical device, can preferably be coated with the at least one multilayer structure at least in sections or areas.

[0056] In a further embodiment of the invention, the at least one multilayer structure is part of a wall of the medical device or is integrated into a wall of the medical device or is formed within a wall of the medical device.

[0057] Furthermore, the at least one multilayer structure can, in principle, be configured in the longitudinal and / or transverse or circumferential direction of the medical device. Preferably, the at least one multilayer structure is configured in the circumferential direction of the medical device.

[0058] Furthermore, at least one multi-layered structure can be designed in a striped shape.

[0059] In particular, the medical device may have a variety of multilayer structures, especially strip-shaped ones, which are formed in the longitudinal and / or transverse or circumferential direction of the medical device.

[0060] In a further embodiment of the invention, the medical device is curved, in particular cylindrically curved.

[0061] Preferably, the medical device is cylindrical, in particular hollow cylindrical, or tubular in shape.

[0062] The medical device is designed as a balloon catheter.

[0063] For the purposes of the present invention, the term "balloon catheter" means a catheter, in particular made of plastic, rubber, silicone, metal or glass, which is equipped with a balloon. The balloon can be inflated, i.e., expanded, with either compressed air or liquid.

[0064] For example, the catheter can be designed as an angiography catheter, embolectomy catheter, cardiac catheter, peripheral venous catheter, central venous catheter, Broviac catheter, Fogarty catheter, Hickman catheter, Swan-Ganz catheter, endotracheal catheter, bronchial catheter, bladder catheter, nephrostomy catheter, ureteral catheter, enterostomy catheter, Shaldon catheter, Demers catheter, balloon irrigation catheter, infusion catheter, pigtail catheter or double-J catheter.

[0065] The catheter is preferably designed as a balloon catheter, especially as a plastic catheter, which has a balloon at its tip that can be inflated with compressed air or liquid (occlusion balloon). The balloon catheter can be used, for example, for angioplasty, especially percutaneous transluminal coronary angioplasty (PTCA), for embolectomy, valvuloplasty, especially in cases of stenosed heart valves, catheterization of the bladder, or for blocking or dilating the bronchi.

[0066] The medical device is designed as a balloon catheter, the balloon of which has at least one multi-layer structure.

[0067] The at least one multilayer structure defines at least one sensor unit, in particular at least one tactile sensor unit. Preferably, the at least one sensor unit is configured in the form of at least one sensor stack, in particular a layered one. The at least one sensor unit is preferably configured to detect a measured quantity, in particular a physical quantity, and to convert it into a measurement signal, preferably an electrical measurement signal. The measured quantity can in particular be a mechanical property, such as extensibility or elasticity, or a structural and / or functional parameter of a tissue, in particular a hollow organ, preferably a blood vessel, in particular an artery. Alternatively or in combination, the measured quantity can be a temperature, a hydrostatic pressure, or another measured quantity, in particular of therapeutic and / or diagnostic interest.

[0068] Preferably, at least one sensor unit is designed to detect a measured parameter, such as extensibility or elasticity, that characterizes a blood vessel, in particular an artery. This advantageously allows for the optimization of diagnostics, especially intraoperative diagnostics, and / or therapy of blood vessel diseases, particularly arteriosclerotic diseases.

[0069] If the medical device is designed as a balloon catheter and the at least one multilayer structure forms part of the balloon of the balloon catheter, the elasticity of a blood vessel, in particular an artery, can advantageously be determined, in particular tactilely, by detecting a resistance, in particular electrical resistance, via the sensor unit, which correlates with an expansion or inflation of the balloon of the balloon catheter or with the pressure used to expand or inflate the balloon of the balloon catheter, in particular increases linearly and / or non-linearly and reversibly, and can in particular be interpreted by comparison with a reference behavior without contact with surrounding tissue.

[0070] According to a second aspect, the invention relates to a method for manufacturing a medical device according to the first aspect of the invention. The product can be designed, in particular, in the form of a metal-polymer laminate composite, especially a metal-polymer laminate membrane, and in particular a thin metal-polymer laminate membrane. The method comprises the following steps: a) Producing at least one multilayer structure with at least one metal layer, in particular with varying surface morphology, and at least one elastomer material layer and b) Transferring, i.e. transferring, the at least one multilayer structure onto a substrate to form a substrate provided with the at least one multilayer structure.

[0071] Preferably, step b) is carried out in such a way that no relevant changes to the surface morphology of the at least one metal layer take place, in particular before the substrate is used as a medical device.

[0072] The substrate can be, in principle, a planar substrate (i.e., flat or even a level surface) or, preferably, a non-planar substrate, particularly a curved one. A cylindrical or cylindrically curved substrate, especially a hollow cylindrical or tubular, or conically shaped substrate, is preferred. Preferably, the substrate is a precursor, in particular a blank, a component such as a part, or a semi-finished product of a medical device.

[0073] Preferably, the at least one multilayer structure is produced on a transfer film, in particular a semi-compliant transfer film, during step a), wherein the transfer film is preferably applied to a substrate. In other words, the at least one multilayer structure is preferably produced on a substrate functionalized or coated with a transfer film. Preferably, the transfer film is removable from the substrate, in particular detachable. A wafer, in particular in the form of a circular or quadrilateral, especially rectangular or square, disc, can be used as the substrate. A suitable wafer can be produced from a monocrystalline or polycrystalline blank (so-called ingot).Furthermore, the wafer can comprise or consist of monocrystalline silicon and / or another material, for example, selected from the group consisting of silicon carbide, gallium arsenide, indium phosphide, and mixtures of at least two of the aforementioned materials. The wafer can also, for example, have a thickness of 0.5 mm. A film with an adhesive layer or side, for example, based on acrylic and / or methacrylate, can be used as the transfer film. Preferably, exposure to UV light reduces the adhesive strength of the adhesive layer or side, which advantageously makes it easier to remove the carrier film from the substrate, while maintaining sufficient adhesion to the substrate to prevent premature detachment of the carrier film during subsequent process steps.In addition to the adhesive layer, the transfer film can have another layer, in particular a non-adhesive layer, for example made of polyethylene terephthalate. The transfer film can be applied to the substrate with a thickness of, for example, 40 µm to 240 µm, in particular 60 µm to 155 µm, preferably 75 µm to 120 µm. Preferably, the substrate is coated on one side with the transfer film, in particular by adhesive bonding.

[0074] Preferably, the at least one elastomeric material layer is applied to the transfer film during step a), particularly by rotary coating. In principle, the at least one elastomeric material layer can be applied directly or indirectly to the transfer film, but preferably after UV exposure of the transfer film to reduce adhesion, in order to avoid contact of the at least one elastomeric material layer with UV light and any associated potential degradation of the at least one elastomeric material layer. Preferably, the at least one elastomeric material layer is applied directly to the transfer film. Furthermore, the at least one elastomeric material layer can be applied only partially, i.e., only in sections or areas, or continuously, i.e., over the entire surface, to the transfer film. Preferably, the at least one elastomeric material layer is applied continuously to the transfer film.Preferably, the at least one metal layer is then applied to the at least one elastomer layer. In principle, the at least one metal layer can be applied directly or indirectly to the at least one elastomer layer. Furthermore, the at least one metal layer can be applied only partially, i.e., only in sections or areas, or continuously, i.e., over the entire surface, to the at least one elastomer layer. Preferably, the at least one metal layer is applied continuously to the at least one elastomer layer.During the spin coating process, the elastomer material layer, or more precisely, the elastomer material or a precursor thereof, particularly in the form of a curable prepolymer (preferably a viscous, curable prepolymer without air inclusions), can be spin-applied to the transfer film at a speed of, for example, 400 rpm to 3000 rpm, particularly 500 rpm to 2000 rpm, and preferably 600 rpm to 900 rpm. Furthermore, the spin coating process can be carried out for a period of 30 s to 120 s, particularly 45 s to 90 s, and preferably 60 s to 80 s. In principle, the spin coating process can be carried out at varying speeds and durations. This advantageously improves the uniformity of the resulting elastomer material layer.Particularly at high rotational speeds, the acceleration (in rpm, read: revolutions per minute per second) can also be varied up to a desired rotational speed. This ensures uniform flow behavior and uniform wetting after the initial application of the precursor of the elastomer material, especially the prepolymer. The acceleration can be varied from 100 rpm to 1000 rpm, particularly from 150 rpm to 800 rpm, and preferably from 200 rpm to 400 rpm. A vacuum or reduced pressure is then preferably applied, for example, for a period of 10 to 20 minutes. This advantageously results in the formation of a defect-free and preferably flat elastomer material layer, particularly in the form of a membrane.The elastomer layer can then be cured, for example at a temperature of 25 °C to 120 °C and particularly over a period of 30 minutes to 48 hours. Curing of the elastomer layer can preferably be carried out in an oven.

[0075] Preferably, the at least one metal layer is applied to the at least one elastomer material layer by means of a process structuring the surface of the at least one elastomer material layer, in particular by means of photolithography, and a subsequent vacuum-based coating process, in particular by means of physical vapor deposition, preferably by means of thermal evaporation, in particular directly or not directly.

[0076] Preferably, at least one adhesion layer is first applied using a process that structures the surface of the at least one elastomer material layer, in particular using photolithography, and a subsequent vacuum-based coating process, in particular using physical vapor deposition, preferably by means of thermal evaporation, at least sectionally or in certain areas, in particular only sectionally or in certain areas or continuously, i.e.fully applied to the at least one elastomeric material layer, in particular directly or not directly, and subsequently the at least one metal layer is applied to the at least one adhesion layer by means of a process structuring the surface of the at least one elastomeric material layer, in particular by means of photolithography, and a subsequent vacuum-based coating process, in particular by means of physical vapor deposition, in particular directly or not directly, preferably directly and while maintaining the vacuum or the negative pressure, in particular when using reactive metals to form the at least one adhesion layer.

[0077] To perform photolithography, a photoresist is preferably first applied to the at least one elastomer material layer. In principle, either a positive or a negative photoresist can be used. A positive photoresist is one that is removed in the altered, particularly exposed, areas. A negative photoresist is one that is removed in the unchanged, particularly unexposed, areas. Preferably, a negative photoresist is used. The photoresist is preferably applied to the at least one elastomer material layer by rotary coating. The rotary coating can be carried out, for example, at a speed of 1000 rpm to 4000 rpm, particularly 2000 rpm to 3000 rpm, and particularly for a period of 45 s to 90 s, preferably 60 s to 75 s.The photoresist applied to the at least one elastomeric material layer can then be heated, particularly at a temperature of 90 °C to 110 °C and especially for a period of 90 seconds to 2 minutes. This allows solvents contained in the photoresist, in particular propylene glycol monomethyl ether acetate (PGMEA), to desorb, thereby stabilizing the photoresist. A photomask is then placed onto the photoresist applied to the at least one elastomeric material layer. A photomask made of, in particular, high-purity quartz glass or calcium fluoride can be used. The photomask can also be provided, for example, on one side with a chromium layer, in particular a structured chromium layer.

[0078] The next step in photolithography is preferably exposure. This advantageously transfers the image of the photomask onto the photoresist. This creates a lithographic mask that allows for further processing, preferably by chemical and / or physical processes. The exposure can be carried out with a radiation dose of 50 mJ / cm² to 150 mJ / cm², particularly 60 mJ / cm² to 120 mJ / cm², and preferably 70 mJ / cm² to 100 mJ / cm². A mercury vapor lamp, especially a high-pressure mercury vapor lamp, can be used as the radiation source. A high-pressure mercury vapor lamp is defined as a mercury vapor lamp that has an operating pressure of up to approximately 1 MPa, which it reaches after a few minutes of heating.The light used to expose the photoresist can in particular have a wavelength of 280 nm to 700 nm, in particular 300 nm to 500 nm, preferably 350 nm to 450 nm.

[0079] After exposure, a tempering step can be carried out, in particular at a temperature of 100 °C to 180 °C, preferably 100 °C to 120 °C, and in particular during a period of 2 min 30 s to 3 min 30 s, preferably 2 min 50 s to 3 min.

[0080] After the tempering step, the exposed photoresist, together with the substrate, the transfer film, and the at least one elastomer layer, can be transferred directly into a preheated oven. The oven is preferably preheated to a temperature lower than that of the tempering step described in the previous paragraph. Preferably, the oven is preheated to a temperature of 100°C.

[0081] After the aforementioned tempering step, and particularly before the photoresist development described below, preferably after switching off the aforementioned oven, the photoresist can be cooled, in particular to a temperature of 18 °C to 30 °C, preferably 20 °C to 25 °C. Furthermore, the photoresist can be cooled, in particular for a period of 5 hours. This advantageously prevents cracking within the photoresist.

[0082] Finally, when performing photolithography, the photoresist is preferably developed. This process dissolves the exposed areas of the photoresist or, particularly if the photoresist is cured under light, the unexposed areas. A developer solution is preferably used for developing the photoresist. This allows the soluble areas of the photoresist to be dissolved, for example, by wet chemical means such as spraying, immersion, or dripping, and then removed. An aqueous solution containing tetramethylammonium hydroxide (TMAH) can be used as the developer solution. Alternatively, a developer solution based on buffered sodium hydroxide solution, buffered potassium hydroxide solution, or sodium phosphate and sodium metasilicate can be used.The photoresist development can be carried out, for example, over a period of 1 min 30 s to 2 min 20 s, in particular 1 min 50 s to 2 min 10. This can then be followed by rinsing with water, in particular deionized water, and drying under an inert gas, in particular nitrogen.

[0083] Alternatively, to structure the surface of at least one elastomer material layer, a hole or stencil mask, for example having or consisting of nickel or a nickel-phosphorus alloy, can be used and subsequently exposed to UV radiation.

[0084] To influence varying surface morphology after deposition of at least one metal layer with or without at least one adhesion layer in different areas, selective plasma treatment of the elastomer material layer surface can be performed, particularly before the elastomer material layer is introduced into a coating chamber. For this purpose, the photolithographic masking and / or the corresponding stencil mask can be designed such that only parts of the areas to be subsequently coated with the at least one metal layer and optionally the at least one adhesion layer are exposed.By placing the elastomer material in a plasma chamber and exposing the exposed surfaces to a plasma, the surface properties of the elastomer material can be altered, thus influencing the surface morphology of the at least one metal layer that subsequently forms during deposition in these areas. The effect of the plasma on the surface of the at least one elastomer material layer also depends on the choice of process gas and the process parameters. To influence layer growth in such a way that a corrugated, closed surface is formed, oxygen can be used as the process gas, preferably at plasma powers of 50 W to 150 W, a process pressure of 0.5 mbar to 1.5 mbar, and a process gas flow rate of 100 sccm (standard cubic centimeters per minute) to 700 sccm, preferably from 300 sccm to 500 sccm.The duration of the plasma treatment can be 5 s to 40 s, in particular 10 s to 35 s, preferably 15 s to 30 s.

[0085] Physical vapor deposition (PVD) can be selected from the group consisting of thermal evaporation, electron beam evaporation, laser beam evaporation, arc evaporation, molecular beam epitaxy, sputtering, ion beam-assisted deposition, ion plating, intrachemical beam fusion (ICB), and a combination of at least two of the aforementioned PVDs. Generally, in PVD, the material to be deposited is in solid form and placed in a usually evacuated coating chamber. The material, which can also be referred to as the target, is vaporized by bombardment with laser beams, magnetically deflected ions or electrons, by arc discharge, or by heating (especially to near its boiling point). The vaporized material moves through the coating chamber either ballistically or guided by electric fields, colliding with the parts to be coated, where it forms a layer.To ensure that the vapor particles reach the parts to be coated and are not lost through scattering by gas particles, the process is generally carried out under reduced pressure. Typical working pressures range from 10⁻⁴ Pa to 10 Pa.

[0086] Preferably, after applying the at least one metal layer to the at least one adhesion layer and / or the at least one elastomer material layer, the photomask, consisting of the unexposed areas of the photoresist, is removed. Preferably, the unexposed areas of the photoresist are removed with an organic solvent, such as acetone.

[0087] In the case of using a hole or stencil mask to structure the surface of the at least one elastomer material layer, the mask is preferably removed after the application of the at least one metal layer to the at least one adhesion layer and / or at least one elastomer material layer, for example by peeling it off.

[0088] Preferably, in carrying out step a), at least one additional elastomeric material layer is applied to the at least one metal layer, in particular by means of rotational coating. Regarding further features and advantages, especially with respect to the at least one additional elastomeric material layer and the rotational coating, reference is made in full to the preceding description. The features and advantages described therein, in particular with respect to the at least one elastomeric material layer, also apply mutatis mutandis to the at least one additional elastomeric material layer.

[0089] Different contacting techniques can be used to connect the at least one metal layer with the at least one adhesion layer between the at least one elastomer material layer and the at least one additional elastomer material layer. For example, contacting can take place in predefined pockets within the at least one additional elastomer material layer, where, for example, conductive, viscous pastes are used to create an electrically conductive connection between defined contact pads of the at least one metal layer with the at least one adhesion layer and leads that lead to an evaluation periphery and are embedded in the at least one additional elastomer material layer.

[0090] Preferably, the at least one multilayer structure together with the transfer film is removed from the carrier before step b) is carried out, in particular detached.

[0091] Preferably, the substrate is applied to a core before step b) is carried out, forming a cylindrical, tubular, or conical substrate. The core is advantageously cylindrical, tubular, or conical in shape. In particular, the core can be stamp-shaped. Furthermore, the core can be made of or comprise a metal. The metal can, for example, be aluminum.

[0092] Preferably, the cylindrical, tubular, or conical substrate is detached from the core, and the core is replaced by a water-soluble material, in particular a water-soluble wax. In other words, the existing core is preferably replaced by a water-soluble core, especially one made of water-soluble wax. The water-soluble wax can have a melting point of 50 °C to 60 °C, particularly 55 °C to 60 °C. Preferably, the detachment of the cylindrical, tubular, or conical substrate from the core and / or the replacement of the core with the water-soluble material is carried out inside a mold or casting tool, particularly a multi-part, preferably two-part, and openable mold or casting tool. Preferably, the mold or casting tool, especially in an assembled or closed state, has a shape that corresponds to the shape of the product to be manufactured.

[0093] Preferably, the at least one multilayer structure is then transferred to the cylindrical, tubular, or conical substrate. This step is preferably carried out outside the mold or casting tool.

[0094] The water-soluble material is then removed, particularly by rinsing with water. This step can preferably be carried out in the mold or casting tool. This advantageously avoids undesirable stresses on the at least one multilayer structure.

[0095] Preferably, the at least one multilayer structure is applied to the substrate using the transfer film during step b). Preferably, the transfer film is removed after a bond, preferably a covalent bond, has formed between the at least one multilayer structure, in particular the at least one elastomeric material layer and / or at least one additional elastomeric material layer of the at least one multilayer structure, and the substrate. The bond can be formed, for example, by curing or crosslinking of the elastomeric material or a precursor thereof, in particular a prepolymer, and can be based in particular on the formation of covalent bonds.Alternatively or in combination, the bond can be based on the formation of non-covalent bonds, in particular selected from the group consisting of van der Waals forces, hydrogen bonds, ionic bonds, coordinate bonds, and a combination of at least two of the aforementioned non-covalent bonds. Furthermore, the bond between the at least one multilayer structure, in particular the at least one elastomeric material layer and / or at least one additional elastomeric material layer of the at least one multilayer structure, and the substrate can be formed in a mold or casting tool, in particular in the aforementioned mold or casting tool.For this purpose, the substrate, which has at least one multilayer structure, can remain in the mold or casting mold for a period of 12 h to 72 h, in particular 24 h to 48 h, and in particular at a temperature of 18 °C to 30 °C, preferably 20 °C to 25 °C.

[0096] Furthermore, the procedure preferably also includes a step c): Forming additional elastomer material, in particular by means of injection molding, onto the substrate provided with the at least one multilayer structure, in particular the at least one multilayer structure transferred to the substrate, i.e. transferred.

[0097] This advantageously allows a final, i.e. definitive, form of the substrate provided with at least one multilayer structure, and thus of the product to be manufactured, to be determined.

[0098] Preferably, step c) is (also) carried out in a mold or casting tool, in particular in the mold or casting tool already mentioned.

[0099] Regarding further features and advantages of the method, full reference is made to the statements made under the first aspect of the invention, which also apply analogously to the method according to the second aspect of the invention.

[0100] Further features and advantages of the invention will become apparent from the claims and from the following description of preferred embodiments with reference to figures and examples. Features of the invention may be implemented individually or in combination. The embodiments described below serve to further explain the invention without limiting it. SAMPLE PART 1. Experimental methods 1.1 MPBC Sample Design

[0101] Metal-polymer multilayer composites, specifically metal-polymer bilayer composites (MPBCs) with a thin (approx. 100 µm) polydimethylsiloxane membrane (PDMS membrane) functionalized with structured 40 nm gold layers, were used. Two different structuring methods were employed: conventional photolithography and a shadow mask. The gold metallization enables strain-sensitive areas as well as lead-in regions that exhibit only minimal resistance changes under load. The lead-in regions comprise self-similar serpentine structures. The sensor region utilizes a strain-sensitive surface with microcracks. An example of a functionalized metal-polymer multilayer composite structure is shown in Figure 1 shown. 1.2 Substrate preparation

[0102] The main steps of the process are in Figure 2As shown, 4-inch wafers 1, polished on one side and 0.5 mm thick, were used as a handling platform. A UV-sensitive dicing film 2 (also known as saw film) made of polyethylene terephthalate (PET) (Adwill D-203, 50 µm) was transferred to the wafer 1 using a soft foam roller 3. The applied film 2 was cut along the wafer edges with a scalpel and then exposed to UV light 4 to reduce its adhesion to the wafer 1 (special equipment with 5 STER-L-RAY® low-pressure mercury lamps). At a minimum dose of approximately 160 mJ / cm², the adhesion was reduced to about 1% of its original value (from 772.2 N / m to 5.8 N / m according to the datasheet). To ensure a uniform and maximum reduction in adhesion, UV activation was carried out at an increased dose of approximately 250 mJ / cm² and under a nitrogen atmosphere to prevent ozone formation.After UV treatment, a degassed, bubble-free PDMS prepolymer 5 (Sylgard 184® elastomer kit, 10:1 ratio (base to hardener), mixed with a THINKY 250-ARE planetary centrifugal mixer) was applied by rotary coating to the handling wafer 1 covered with film 2 at 600 rpm (acceleration 200 rpm / s) for 60 seconds. A vacuum was then applied (10 minutes) to ensure a defect-free and uniform membrane before it was cured in an oven at 90 °C for 30 minutes. 1.3 Structuring of the PDMS membrane

[0103] In the case of photolithographic structuring, a negative lift-off photoresist 6 (AZ nLOF®< 2070, Merck KGaA) was applied directly to the PDMS surface by rotary coating at 3000 rpm (acceleration 1000 rpm / s) for 60 seconds. Soft baking at 100 °C for 2 minutes on a hot plate resulted in a photoresist thickness of approximately 6.5 µm. Exposure 7 with a chrome mask 8 employed a SUSS MA6 mask aligner (350 W high-pressure mercury lamp) at a dose of 70 mJ / cm²<. The subsequent baking (post-exposure bake PEB) was performed on a hot plate for 3 minutes at 115 °C. To prevent cracking in the stabilized photoresist layer due to differing coefficients of thermal expansion of the layers involved in the multilayer structure, the exposed wafers were transferred directly into a preheated oven at 100 °C. They were then allowed to cool slowly to room temperature over a period of approximately 5 hours.For development, the AZ developer (Merck KGaA, undiluted, high-speed configuration) was prepared in a laboratory glass on an analog orbital shaker (RS-OS 5 Phoenix Instruments). With gentle fluid agitation, the structures were developed for 1 minute 50 seconds, then rinsed with DI water and dried under a nitrogen stream.

[0104] In the case of structuring the metal layer in a shadow mask process, a 50 µm nickel stencil mask 9, manufactured by applied microSWISS GmbH in a suitable UV-LIGA process, was used. Since the mask had the outer dimensions of a standard 4-inch wafer, the mechanics of the SUSS MA6 mask aligner were used to apply the mask to the PDMS membrane surface via flat alignment and magnets. The precise contact between the PDMS and the smooth mask surface ensured stable positioning due to van der Waals interactions without the need for additional fixation. 1.4 PVD metal deposition and removal

[0105] The vapor deposition 10 was performed by thermal evaporation in an Edwards Auto 306 vacuum coating system. To improve the adhesion of the 40 nm Au top layer, a 4 nm Ti intermediate layer was deposited beforehand without interrupting the vacuum (approximately 2 × 10⁻⁶ mbar). After the coating process, either the photoresist was dissolved in acetone with slight fluid excitation and the resulting multilayer system was then rinsed with DI water, or the shadow mask was gently peeled from the PDMS surface. Subsequently, the UV-activated stabilizing transfer film 2 could be easily removed from the wafer 1 without exerting any significant stress on the thin functionalized PDMS membrane 6. 2. Transmission procedure

[0106] In Figure 3The transfer process onto a cylindrical PDMS base substrate 11 is shown. The cylindrical base 11 was cast in a special polymethyl methacrylate (PMMA) mold with a constant outer diameter of 10 mm. The wall thickness was mostly 400 µm and only 200 µm in specified areas. Since the described transfer used a PDMS-to-PDMS bond via partial curing, it was practical to apply the intermediate PDMS bonding layer by rotational coating before removing the film. A PDMS-to-PDMS bond via partial curing enabled high bond strengths while being easy to execute. Here, a thin PDMS layer approximately 60 µm thick was applied to the top surface of the structured layer by rotational coating at 900 rpm for 60 s (acceleration 200 rpm / s) and then cured for 45 min at 50 °C.This resulted in stabilization of the PDMS film while maintaining sticky properties comparable to an intermediate adhesive layer. Subsequently, the relevant sample portion was pre-cut with a scalpel, and the stabilizing transfer film 2 was detached from the handling wafer using tweezers (see step 4 in ). Figure 2 ) and the partially hardened PDMS surface was attached to the appropriate position on the cylindrical base 11 (step 1 in Figure 3 The test piece was then placed in a cylindrical PMMA mold 12 and left there at room temperature for 48 hours to fully cure. As a final step, the transfer film 2 was removed from the bonded membrane layer 13 ( Figure 3 , step 2), and another casting process was carried out ( Figure 3, steps 3 + 4) and subsequent hardening at room temperature for 48 h to obtain a uniform cylindrical sensor. 3. Characterization and Results

[0107] To ensure that the transferred metal morphology was not altered by undefined stresses after the final step, it was necessary to carefully remove the finished PDMS cylinder from the mold. Therefore, the inner part of the mold, which defined the variable wall thickness of the PDMS base cylinder, was replaced with a water-soluble adhesive wax (2-M19 soluble stic wax, Paramelt BV) before the transfer process. This required that the subsequent curing steps of the bonding process and the final casting steps be carried out at a low temperature to prevent the wax from melting (dropping melting point approximately 57 °C).

[0108] Figure 4The finished PDMS cylinder with integrated sensor structures is shown. To demonstrate the claim that the process enables the handling and transfer of fragile surface morphologies, various surfaces (with microcracks and wavy periodic structures) were introduced through selective plasma pretreatment and by varying the deposition rate. To characterize the morphology in the initial state before joining, after removal from the handling wafer, and in the final state at the cylindrical base, the same structure was examined at each step using a SEM (Philips XL30). To characterize the morphology after transfer to the cylindrical base, a special aluminum fixture simulating the curvature of the PDMS base was used.

[0109] In Figure 5A selected morphological area of ​​the prepared specimen is shown at each relevant step of the presented procedure. As can be seen, the fragile crack morphology did not change during handling of the membrane, and the only change involved slight compression due to the curvature of the cylindrical base ( Figure 5 c) , while neither delamination nor crack propagation was observed. Furthermore, simple two-wire resistance measurements showed that the electrical integrity of the structure was maintained at approximately 4 kΩ.

[0110] Since there are various methods for bonding the membrane to the substrate, a 90° peel test (see DIN EN 28510-1:2014) was performed to determine the necessary peel force for removing the cover film from the PDMS membrane (step 2, Figure 3For this purpose, test specimens with a 100 µm PDMS membrane were prepared according to the substrate preparation procedure described above (step 1, Figure 2The PDMS surface was detached from the handling wafer and bonded to the polished side of pre-cut wafer pieces (30 mm wide) after activation in an oxygen plasma (30 sec at 100 W). The transfer film was then attached to the load cell of the peel tester, and tests were performed at a constant speed of 50 mm / min with a peel angle of 90°. Since the investigations were limited by the size of the wafers and the width of the flats (wafers were cut perpendicular to the main flat near the edges of the flat), the maximum peel length was 90 mm and the peel width used was 20 mm. A total of five samples with peel lengths between 20 mm and 80 mm were tested and analyzed to eliminate edge effects. The mean peel force was determined to be 0.07 N / mm (SD 0.011 N / mm). Nr. Peeling force [N / mm] 1. 0.076 2. 0.076 3. 0.082 4. 0.078 5. 0.051 Ø 0.07 Standard deviation 0.01

Claims

1. A medical device having at least one multilayer structure that includes the following layers arranged on top of one another: - at least one metal layer and - at least one elastomer material layer, characterized in that the at least one multilayer structure defines a sensor unit of the medical device, wherein the medical device takes the form of a balloon catheter and the balloon of the catheter includes the at least one multilayer structure.

2. The medical device as claimed in claim 1, characterized in that the at least one elastomer material layer includes an elastomer material, more particularly a hyperelastic material, or consists of an elastomer material, more particularly hyperelastic material, selected from the group consisting of elastomers, thermoplastic elastomers, thermoplastic polyamide elastomers, thermoplastic copolyester elastomers, olefin-based thermoplastic elastomers, thermoplastic styrene block copolymers, urethane-based thermoplastic elastomers, olefin-based thermoplastic vulcanizates, olefin-based crosslinked thermoplastic elastomers, natural rubber vulcanizates, synthetic rubber vulcanizates, styrene-butadiene rubber, butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), polyisoprene rubber (IR), polyalkylsiloxanes, polydimethylsiloxane, silicone rubbers, silicone elastomers, methyl silicone, vinyl methyl silicone, phenyl vinyl methyl silicone, phenyl-modified silicone, fluoroalkyl silicone, fluoro vinyl methyl silicone, and mixtures of at least two of the aforementioned elastomer materials.

3. The medical device as claimed in claim 1 or 2, characterized in that the at least one metal layer includes at least one metal, more particularly in elemental form or in the form of an alloy, or consists of at least one metal, more particularly in elemental form or in the form of an alloy, selected from the group consisting of gold, platinum, indium, tin, copper, silver, gallium and alloys of at least two of the aforementioned metals.

4. The medical device as claimed in any of the preceding claims, characterized in that the at least one elastomer material layer has a layer thickness of 0.0001 mm to 0.2 mm, more particularly 0.0005 mm to 0.1 mm, preferably 0.001 mm to 0.05 mm, and the at least one metal layer has a layer thickness of ≤ 150 nm, more particularly 10 nm to 100 nm, preferably 40 nm to 80 nm.

5. The medical device as claimed in any of the preceding claims, characterized in that the at least one metal layer directly covers the at least one elastomer material layer.

6. The medical device as claimed in any of the preceding claims, characterized in that at least one adhesion layer is formed between the at least one metal layer and the at least one elastomer material layer.

7. The medical device as claimed in claim 6, characterized in that the at least one metal layer covers the at least one adhesion layer directly and completely and the at least one adhesion layer covers the at least one elastomer material layer directly and only in regions.

8. The medical device as claimed in claim 6 or 7, characterized in that the at least one adhesion layer includes at least one material or consists of at least one material selected from the group consisting of titanium, aluminum, chromium, and mixtures of at least two of the aforementioned materials.

9. The medical device as claimed in any of the preceding claims, characterized in that the at least one multilayer structure further includes at least one additional elastomer material layer that directly covers the at least one metal layer.

10. The medical device as claimed in any of the preceding claims, characterized in that the at least one multilayer structure or the at least one metal layer has a varying surface morphology, more particularly surface regions with cracks, more particularly microcracks, and surface regions, more particularly corrugated surface regions, without cracks.

11. The medical device as claimed in any of the preceding claims, characterized in that the at least one multilayer structure forms part of a surface of the medical device or is integrated in a wall of the medical device.

12. A process for producing a medical device according to any of the preceding claims, including the following steps: a) producing at least one multilayer structure having at least one metal layer and at least one elastomer material layer and b) transferring the at least one multilayer structure to a substrate, with the formation of a substrate provided with the at least one multilayer structure, wherein the at least one multilayer structure defines a sensor unit of the medical device, wherein the medical device takes the form of a balloon catheter and the balloon of the catheter includes the at least one multilayer structure.