Rough Surface Adhesive System

Abstract

The present invention relates to a device with a structured coating for adhesion to rough surfaces, particularly biological surfaces, comprising a carrier layer (101) on which a plurality of protrusions are arranged, each of the protrusions comprising at least one stem having an end face facing away from the surface, and a further layer (104) arranged on at least the end faces, said layer having a lower modulus of elasticity and in the form of a film interconnecting the protrusions. The film may be in the form of a removable film.

Description

[Technical Field]

[0001] The present invention relates to devices having a structured coating for adhesion to rough surfaces, particularly biological surfaces, such as skin surfaces, including eardrums. [Background technology]

[0002] Adhesion to rough surfaces is often problematic. Many adhesives exhibit particularly poor properties in the biological field. At the same time, adhesives often lack sufficient compatibility with biological processes, such as wound healing.

[0003] One alternative is offered by dry adhesive surfaces, such as gecko structures, which can exhibit adhesion to rough surfaces without the aid of an adhesive.

[0004] Adhesion to skin surfaces in particular is not simple, since these surfaces are rough and soft. The surfaces are also often curved rather than flat. At the same time, the adhesive system must be removable again without leaving any residue. Therefore, the adhesive system must first be flexible, but also adhere with sufficient strength.

[0005] Another application area for adhesive systems is tympanic membrane perforation. Tympanic membrane perforation is a frequent problem that can lead to hearing loss or frequently recurring infections. Frequent causes of tympanic membrane perforation can be middle ear inflammation, trauma, and postoperative complications. A fundamental distinction can be made between acute (relatively small) perforations, which close spontaneously in the majority of cases, and large or chronic perforations. These large perforations require surgical care in the form of tympanoplasty or tympanoplasty, which, although highly successful, poses not only surgical risks but also the risk of residual perforation. Furthermore, in the case of tympanoplasty, autologous tissue must be transplanted and then removed. One of the main problems in the regeneration of tympanic membrane damage is the lack of a backing layer for epithelial cell migration and the formation of a trilayer membrane. Generally, either transplanted tissue or polymers can be used as a "support platform," the function of which can be improved by the use of biomolecules. Polymers that can be used include gelatin, silk fibroin, chitosan, alginate, or polyglycerol sebacate, among others. A current review of the results of using these polymers and various growth factors can be found in the review by Hong et al. (Int. J. Pediatr. Otorhinolaryngol. 77, 3-12 (2013). Many of the polymers used provide significant results in terms of closing the perforation, but there are significant differences in tissue morphology.

[0006] Hamed Shahsavan et al., Soft Mater 2012, 8, 8281, "Biologically inspired enhancement of pressure-sensitive adhesives using a thin film-terminated fibrillar interface," Hamed Shahsavan et al., Macromolecules 2014, 47, 353-364, and Drotlef et al., Integrative and Comparative Biology 2019, 1-9, describe various systems with film-terminated microstructures. They use pillars (Sylgard 184) with a high elastic modulus of approximately 2.7 MPa for their structure. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to identify a device having a structured coating that exhibits adhesion to particularly rough and / or biological surfaces and avoids the drawbacks of the prior art. [Means for solving the problem]

[0008] This object is achieved by the invention with the features of the independent claims. Advantageous developments of the invention are characterized in the dependent claims. The wording of all claims is incorporated into this description by reference. The invention also encompasses all reasonable combinations of the independent and / or dependent claims, more particularly all described combinations.

[0009] This object is achieved by a device with a structured coating, which comprises a backing layer having a number of protrusions (pillars) including stems having end faces in each case pointing outward from the surface, the end faces having at least one further layer configured as a film, which layer comprises as a surface at least one layer having a lower modulus of elasticity than the respective protrusions.

[0010] This layer, configured as a film, connects the various protrusions. The film itself can comprise different layers, the outermost layer forming the surface of the film opposite the protrusions and having a lower modulus of elasticity than the protrusions. This layer forms the contact with the surface to which the device is applied.

[0011] Thus, in the vertical direction, starting from the backing layer at the location of the protrusion, the device comprises at least two regions with different elastic moduli, these regions being at least the protrusion and a further layer arranged thereon. The end face of this further layer and the protrusion forms an interface between the two regions with different elastic moduli. Depending on the manufacturing process, this interface may also comprise a thin layer of a connection aid.

[0012] Within the region, the modulus of elasticity is preferably constant.

[0013] The protrusion itself may also have further regions with different moduli of elasticity, in which case the lower modulus of elasticity of the further layer is always related to the region of the protrusion with the highest modulus of elasticity.

[0014] The additional layer has a lower modulus of elasticity than the protrusion that carries it. The effect of this structure is that the outermost layer of the device is particularly soft. As a result, the layer is more elastic and can conform more effectively to rough and / or soft surfaces.

[0015] For an overall very soft device, the device can also conform very well to curved surfaces.

[0016] The device of the invention has a roughness depth R of at least 30 μm, preferably at least 40 μm, in direct comparison with a smooth surface having a roughness depth of 0.1 μm. z The device therefore exhibits particularly good adhesion to surfaces having a roughness depth Rz of at most 100 μm, more particularly at most 80 μm, in particular at most 70 μm.

[0017] In a further embodiment of the invention, the interface between the further layer and the end face is parallel to the surface of the further layer relative to the respective protrusion.

[0018] In one embodiment of the present invention, the ratio of the minimum vertical thickness of the further layer above the protrusion to the height of the protrusion is less than 3, preferably less than 1, more particularly less than 0.5, and even more particularly less than 0.3. As a result, the protrusion below the layer has a particularly strong effect on adhesion. The optimal ratio may also depend on the ratio of the elastic moduli and the shape of the interface.

[0019] The advantageous parameters of modulus, size ratio and interface shape can be determined by simulation and measurement.

[0020] In one preferred embodiment of the present invention, the protrusions on the backing layer have a columnar configuration, which means that the protrusions are preferably configured perpendicular to the backing layer and have a stem and an end face, and the stem and end face can have any desired cross section (e.g., circular, oval, rectangular, square, diamond, hexagonal, pentagonal, etc.).

[0021] The protrusion is preferably configured such that a perpendicular projection of the end face onto the base region of the protrusion forms an overlap region with the base region, and the overlap region and the projection of the overlap region onto the end face produce a body that is entirely within the protrusion. In a preferred embodiment of the invention, the overlap region comprises at least 50% of the base region, preferably at least 70% of the base region, and more preferably the overlap region comprises the entire base region. Thus, the protrusion is preferably not angled, although it may be angled.

[0022] In a preferred embodiment, the end faces are oriented parallel to the base region and the surface. If the end faces are not oriented parallel to the surface and therefore have different vertical heights, the vertical height of the protrusions is considered to be the average vertical height of the end faces.

[0023] In one preferred embodiment of the present invention, the stem of the projection has a height to diameter aspect ratio of 1 to 100, preferably 1 to 10, more preferably 1.5 to 5, based on its average diameter.

[0024] In one embodiment, the aspect ratio is greater than 1, preferably at least 1.5, preferably at least 2, preferably 1.5-15, more preferably 2-10.

[0025] The average diameter here is understood as the diameter of a circle having the same area as the corresponding cross section of the protrusion, averaged over the entire height of the protrusion.

[0026] In another embodiment of the invention, the ratio of the height of the protrusion to the diameter at a particular height over the entire height of the protrusion is always between 1 and 100, preferably between 1 and 10, more preferably between 1.5 and 5. In one embodiment, this aspect ratio is at least 1, preferably between 1 and 3. Diameter here is understood to be the diameter of a circle having the same area as the corresponding cross section of the protrusion at a particular height.

[0027] The protrusions may have a wide end face, known as a "mushroom" structure. It is also possible for additional layers to protrude above the end face, thereby forming a "mushroom" structure.

[0028] In a preferred embodiment, the protrusion does not have a wide end face.

[0029] In a preferred embodiment, the vertical height of all protrusions is in the range of 1 μm to 2 mm, preferably 10 μm to 1 mm, more particularly 10 μm to 500 μm, preferably 10 μm to 300 μm.

[0030] In a preferred embodiment, the total vertical thickness of the further layers, including all layers included above the end face, is in the range of 1 μm to 1 mm, preferably 1 μm to 500 μm, more particularly 1 μm to 300 μm, preferably 1 μm to 200 μm, more particularly 5 μm to 100 μm, in particular 5 μm to 60 μm.

[0031] The further layer preferably has a vertical thickness in the above range or one of the preferred ranges, based on at least 50% of the projection of the base area of ​​the protrusion onto the surface of the further layer, which thickness is also preferably the average thickness of the entire further layer across the device.

[0032] Preferably, the minimum thickness of the further layer above the protrusion is always less than the maximum vertical height of the protrusion.

[0033] In a preferred embodiment, the vertical thickness of the backing layer is in the range of 1 μm to 2 mm, preferably 20 μm to 500 μm, more particularly 20 μm to 150 μm. In a preferred embodiment, the thickness of the backing layer is 20 to 60 μm.

[0034] In a preferred embodiment, the base region corresponds in area to a circle having a diameter of 0.1 μm to 5 mm, preferably 0.1 μm to 2 mm, particularly preferably 1 μm to 500 μm, very particularly preferably 1 μm to 100 μm. In one embodiment, the base region is a circle having a diameter of 0.3 μm to 2 mm, preferably 1 μm to 100 μm.

[0035] The average diameter of the stems is preferably 0.1 μm to 5 mm, preferably 0.1 μm to 2 mm, particularly preferably 10 μm to 100 μm. The height and the average diameter are preferably adapted according to the preferred aspect ratio.

[0036] In a preferred embodiment, in the case of a wide end face, the surface of the end face of the protrusion, or of the further layer, is at least 1.01 times, preferably at least 1.5 times, the area of ​​the base region of the protrusion, which may for example be 1.01 to 20 times larger.

[0037] In another embodiment, the wide end face is 5% to 100% larger than the base region, more preferably 10% to 50% larger than the base region.

[0038] In a preferred embodiment, the distance between two protrusions is less than 2 mm, more particularly less than 1 mm, in particular less than 500 μm or less than 150 μm, where distance is understood to be the shortest distance between two protrusions.

[0039] The protrusions preferably have a regular periodic arrangement.

[0040] In a preferred embodiment of the invention, the protrusions have a height of 5 to 500 μm, preferably up to 400 μm. The further layer has a total vertical thickness above the end face of 3 to 100 μm. The average distance between the columnar protrusions is between 5 and 50 μm. The thickness of the backing layer is between 50 and 200 μm. The diameter is between 5 and 100 μm, depending on the distance between the protrusions. The protrusions are preferably arranged hexagonally. Very preferably, the density of the protrusions is between 10,000 and 1,000,000 protrusions / cm. 2 is.

[0041] The total thickness of the device, including further layers, protrusions and backing layer, is preferably between 50 μm and 500 μm. The thicknesses of the individual components are adapted correspondingly.

[0042] In one embodiment of the invention, the total thickness of the device is between 40 and 90 μm. For these thin devices, it is preferred that the protrusions occupy at least 30%, preferably at least 40%, of the total height of the device.

[0043] The elastic modulus of all regions of the protrusions and further layers is preferably 40 kPa to 2.5 MPa. The elastic modulus of the soft regions, i.e., in particular of the further layers having a lower elastic modulus, is preferably 40 kPa to 800 kPa, preferably 50 kPa to 500 kPa, more preferably 50 to 150 kPa. Independently of this, the elastic modulus of the regions having a higher elastic modulus, such as the protrusions and, for example, the backing layer, is preferably 1 MPa to 2.5 MPa, preferably 1.2 MPa to 2 MPa. Preferably, the elastic modulus of all softer and harder regions is within the above ranges (measured using a nanoindenter).

[0044] The ratio of the moduli between the regions with the lowest and highest moduli is preferably less than 1:100, more particularly less than 1:80, preferably less than 1:70, and regardless of these is at least 1:2, preferably at least 1:3.

[0045] In one preferred embodiment, the modulus of elasticity of the regions of the protrusions and backing layer, and, where appropriate, further layers, is between 1 MPa and 2.5 MPa, preferably between 1.2 MPa and 2 MPa, while the modulus of elasticity of the regions with lower modulus is between 40 kPa and 800 kPa, preferably between 50 kPa and 500 kPa, more preferably between 50 and 150 kPa (measured using a nanointender).

[0046] The use of such soft materials for the protrusions and backing layer allows for the fabrication of relatively thick, yet relatively flexible, devices with adhesion values ​​similar to those of more rigid structures, yet still very flexible. The film-mediated connection provides additional stabilization of the protrusions, thereby preventing collapse of the soft protrusions. At the same time, thicker devices are easier to fabricate and handle.

[0047] As a result of the stabilization by the membrane, the device itself is also stabilized. This is important, for example, when the device is intended to withstand not only adhesion but also tensile forces parallel to the contact surface, such as in applications to closed wounds or eardrum injuries. This allows for a further reduction in the modulus of elasticity of the protrusions and backing layer, particularly without losing the stability of the protrusions.

[0048] In another embodiment, the ratio specified above represents the ratio of the modulus of elasticity of the further layer (soft) and the protrusion (hard).

[0049] This layer is also easy to keep clean and sterile, as no dirt can accumulate in the gaps. When used on the eardrum, the result is an infection barrier, especially against microorganisms. This "seal" also improves hearing in the event of a perforation of the eardrum.

[0050] This gives the surface of the device in this embodiment a coherent, unitary appearance, which can then be more easily modified to suit the application, where the treatment of the surface does not affect the structuring within the coating.

[0051] Thus, the surface can be treated or functionalized by known processes.

[0052] The gaps between the protrusions in the device are preferably unfilled, although the gaps can be filled with a material having a different modulus of elasticity than the protrusions and the backing layer.

[0053] The protrusions can be made of a number of different materials, with elastomers being preferred and crosslinkable elastomers being especially preferred. The regions having a higher modulus may also comprise a thermoset resin.

[0054] Thus, the protrusions and further layers may comprise the following materials: Epoxy and / or silicone elastomers, polyurethanes, epoxy resins, acrylates, methacrylates, polyacrylates as homopolymers and copolymers, polymethacrylates (PMMA, AMMA acrylonitrile / methyl methacrylate) as homopolymers and copolymers, polyurethane (meth)acrylates, silicones, silicone resins, rubbers such as R rubber, NR natural rubber, IR polyisoprene rubber, BR butadiene rubber, SBR styrene-butadiene rubber, CR chloropropene rubber, NBR nitrile rubber, M rubber (EPM ethene-propene rubber, EPDM ethylene-propylene rubber), unsaturated polyester resins, formaldehyde resins, vinyl ester resins, polyethylene as homopolymer or copolymer, and mixtures and copolymers of the above materials. Also preferred are elastomers approved by the EU (EU Regulation No. 10 / 2011 of January 14, 2011, published January 15, 2011) or the FDA for use in the packaging, pharmaceutical, and food sectors, or silicone-free UV-curable resins from PVD and CVD process engineering. Polyurethane (meth)acrylates herein refer to polyurethane methacrylates, polyurethane acrylates, and mixtures and / or copolymers thereof.

[0055] The material in question may also be a hydrogel based on, for example, polyurethane, polyvinylpyrrolidone, polyethylene oxide, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), silicone, polyacrylamide, hydroxylated polymethacrylate or starch.

[0056] Epoxy and / or silicone elastomers, polyurethane (meth)acrylate, polyurethane, silicone, silicone resin (eg, UV-curable PDMS), polyurethane (meth)acrylate, rubber (EPM, EPDM, etc.) are preferred.

[0057] Crosslinkable silicones, such as vinyl-terminated silicone-based polymers, are particularly preferred.

[0058] In particular for the further layer in contact with the surface, among the materials specified above, epoxy- and / or silicone-based elastomers, polyurethane (meth)acrylates, polyurethanes, silicones, silicone resins (e.g. UV-curable PDMS), polyurethane (meth)acrylates, rubbers (EPM, EPDM, etc.), more particularly polymers based on crosslinkable silicones, e.g. vinyl-terminated silicones, are preferred.

[0059] It is also possible to use the above-mentioned hydrogels or pressure-sensitive adhesives in the further layers.

[0060] In one preferred embodiment of the present invention, the additional layer comprises at least one layer with a relatively high elastic modulus (hardness), preferably the protruding elastic modulus, and a layer with a lower elastic modulus thereon. The lower layer (support layer) stabilizes the layer with the lower elastic modulus (adhesive layer). As a result, it is possible to use a particularly soft material for this layer without the layer sinking between the protruding parts.

[0061] In this embodiment, the support layer is between 1 and 100 μm thick and the adhesive layer is between 5 and 100 μm thick, preferably the support layer is between 1 and 50 μm thick and the adhesive layer is between 10 and 50 μm thick, and very preferably the support layer is between 1 and 20 μm thick and the adhesive layer is between 1 and 20 μm thick.

[0062] In another preferred embodiment of the invention, the further layer only has a relatively low modulus of elasticity (adhesion layer), in which case there is in fact a certain sinking of the layer between the protrusions, but due to the high elasticity of the layer, adaptation to rough surfaces is still very effectively possible.

[0063] In this embodiment, the thickness of the further layer is between 5 and 100 μm, preferably between 10 and 50 μm.

[0064] In another embodiment, the surface of the further layer is treated. The surface properties can be influenced in this way. This can be preferably done by physical treatment, such as plasma treatment with Ar / O2 plasma.

[0065] For example, it is possible to form covalent or non-covalent bonds to the surface additives in order to achieve a certain compatibility with cells. Preferred additives are those that support cell adhesion, such as poly-L-lysine, poly-L-ornithine, collagen or fibronectin. These types of additives are known from the field of cell culture.

[0066] Particularly in the context of medical use, it may also be advantageous to house and then slowly deliver substances in at least part of the device, which may be, for example, pharmaceuticals such as antibiotics or adjuvants to support cell adhesion or cell growth.

[0067] In another embodiment, the protrusions and the backing layer are made of the same material.

[0068] In another embodiment of the invention, the further layer having a lower modulus is implemented so as to be removable from the device, preferably the entire further layer of the device is removable. Removable here means in particular that there are no covalent bonds between the removable layer and the rest of the device, for example between the protrusions and the further layer. The bond is based solely on non-covalent bonds.

[0069] In one preferred embodiment of the invention, the additional layers, starting from the end face, include a low modulus layer for bonding to the end face, a support layer, and an even lower modulus layer for adhering to the surface.

[0070] Low modulus layer The adhesive layer serves to adhere to the protrusions and is connected only by adhesive forces. As a result, it is possible to separate the part of the device with the protrusions and reuse it.

[0071] The outermost layer of the device is easily soiled by contact with the surface and therefore cannot be reused after removal, for example in medical applications. If a further layer can simply be replaced with this layer, the part of the device with the protrusions can be easily reused by simply applying a new further layer. The coated support layer is easier to manufacture than the part of the device with the protrusions.

[0072] In one preferred embodiment of the present invention, the additional layer is removable and has the following structure, starting from the protrusion: an inner adhesive layer, a support layer, and an outer adhesive layer. The inner support layer serves to stabilize the removable additional layer to prevent tearing during removal. In this case, the layer also has better handling qualities. The adhesive layer to the protrusion ensures adhesion of the additional layer to the protrusion.

[0073] In this embodiment, the further layer has a total thickness of 50 to 300 μm, preferably 50 to 150 μm.

[0074] In this case, the thickness of the inner adhesive layer is preferably 5 to 100 μm, preferably 10 to 50 μm. Independently, the support layer has a thickness of 5 to 100 μm, preferably 10 to 50 μm. Independently, the outer adhesive layer has a thickness of 10 to 50 μm.

[0075] In a preferred embodiment, the modulus of elasticity of the support layer is 1 MPa to 2.5 MPa, preferably 1.2 MPa to 2 MPa, and the modulus of elasticity of the adhesive layer is 40 kPa to 800 kPa, preferably 50 kPa to 500 kPa, more preferably 50 to 150 kPa.

[0076] The dimensions of the microstructures correspond to those detailed above for other embodiments.

[0077] In this embodiment with a removable further layer, it also allows the use of microstructures made of a relatively hard material and achieving improved adhesion as well.

[0078] In this embodiment, the elastic modulus of the protrusions and the backing layer is preferably 1 MPa to 4 MPa, more preferably 1 MPa to 3 MPa, more preferably 1 MPa to 2.5 MPa, and particularly preferably 1.2 MPa to 2 MPa.

[0079] In another embodiment, the device also comprises an additional, optionally removable layer. Thus, the surface can be protected by a removable film before use. An additional stabilizing layer can also be disposed on the backing layer.

[0080] The backing layer preferably has a thickness less than the maximum height of the protrusions it supports.

[0081] When the backing layer is constructed from the same material as the protrusions, it also comprises a material with a relatively high modulus of elasticity, so that the thickness of the backing layer can be used to affect the elasticity of the entire device.

[0082] The device of the present invention is preferably configured to adhere onto a flexible substrate.

[0083] The device of the present invention is more particularly configured for adhesion to biological tissue. For this purpose, it may be implemented, for example, as a film. It can also be implemented in combination with a device to be fixed. These may be, for example, covering materials, other electrodes, or other medical devices, such as implants, more particularly implants that are not permanently fixed to bone, or soft implants. These may be, for example, iris implants. The present invention therefore also relates to implants, for example, comprising the device of the present invention on at least a portion of the surface of the implant.

[0084] The present invention further relates to the use of the above-described device for adhering to biological tissue. These may be any desired tissue or internal tissue, such as the surface of an organ, such as the skin, the surface of a wound, or the eardrum. When attached to the skin, this may be healthy or damaged tissue. The device can be used, for example, to fix sensors, dressings, patches, injections, etc. Alternatively, the device may be applied to damaged tissue, such as superficial injuries, such as wounds, burns, pressure points, and chronic wounds. The device allows for the combination of a highly conformable surface with simultaneous adhesion to biological tissue. Thus, the device can also function as a growth substrate for cell culture or for new tissue to be formed. The open interior structure of the device allows for the drainage of liquids or the circulation of air.

[0085] Treatment of eardrum perforation As a result of the device's adhesion, it adheres very well to the surface of the tympanic membrane, allowing it to be applied under stress or even to be applied with stress. Due to its structure, it adheres not only to the tympanic membrane but also to the surrounding tissue. A device configured in this way may optionally include different areas with different adhesive properties. This can be achieved, for example, by the material, the thickness of additional layers, or simply by the distribution of protrusions within the device.

[0086] Thus, a device advantageously implemented as a film includes at least a backing layer having protrusions to which further layers are applied. As a result of being implemented as a film, the device can be easily trimmed to a desired size, which may be performed by a person performing the procedure, such as a physician.

[0087] As a result of its internal structure, the device adheres well to the tissue to which it is applied, which may be the tissue surrounding the eardrum as well as the eardrum itself. No liquid component that can flow into the ear is required to apply the device.

[0088] Depending on the material used, the device may be transparent, so that the condition of the tissue underneath the device can be examined without removal, for example to determine healing.

[0089] The device can be easily removed again.

[0090] Prior to deployment, the device may also be physically or chemically treated, preferably for sterilization. This may be, for example, by autoclaving, e.g., hot air sterilization, or steam sterilization at 50-200°C, more specifically 100-150°C, under a pressure of 1-5 bar for 5 minutes to 3 hours. No significant change in adhesive stress was observed during such autoclaving (121°C, 2 bar, 20 minutes).

[0091] Further sterilization methods are, for example, gamma radiation or ethylene oxide sterilization (ETO).

[0092] In another embodiment, the surface may be treated with, for example, poly-L-lysine, poly-L-ornithine, collagen, fibronectin, gelatin, laminin, keratin, tenascin or perlecan. Such additives are known from the cell culture sector.

[0093] The present invention further relates to a process for manufacturing one embodiment of the device of the present invention.

[0094] The individual process steps are described in more detail below: The steps do not necessarily have to be performed in the order listed, and the outlined processes may include additional steps not listed.

[0095] To this end, in a first step, a template is provided for modeling a number of protrusions.

[0096] The material of the protrusions is introduced into the template preferably as a liquid, and optionally may also already be at least partially hardened.

[0097] The material of the backing layer, i.e. the surface with the protrusions, is then applied to the template and cured, and particularly preferably this is the same material as the stems of the protrusions, so that the backing layer and the stems are also produced in one step, for example by direct introduction of a relatively large amount of material.

[0098] In the next step, the backing layer and protrusions are separated from the template.

[0099] For example, it may be necessary to use fluorosilane to deactivate the template before filling.

[0100] It may also be necessary to align the protrusions by mechanical action, for example by hammering or brushing.

[0101] The material for one of the additional layers is also distributed on the surface, for example by spin coating, and then this layer is cured. This may be repeated multiple times using different materials.

[0102] To attach the protrusions, a curable material is applied to the top layer, for example by spin coating. The microstructure with the protrusions is then placed on this layer so that its end faces are in contact with the layer. The entire device is then cured, so that the additional layers are firmly attached to the protrusions. The device is then separated from the surface.

[0103] Depending on the material and structure, it may be necessary to carry out a plasma treatment, preferably oxygen plasma or air plasma, between the application of the various materials, which makes it possible to minimize the influence of the different layers during the curing process, and also improves adhesion.

[0104] It may also be necessary to plasma treat the end faces of the microstructures before placement, for example if the contact area of ​​the microstructures is particularly small.

[0105] Problems during removal can occur, especially if the first layer applied is very soft.

[0106] In another embodiment, a layer of material having a different solubility than the material of the cured device is applied to the substrate, allowing it to be selectively dissolved.

[0107] Further layers and microstructures are then applied to this help layer, as described above. The help layer is then selectively dissolved, and the resulting device is separated from the substrate. The help layer material is preferably water-soluble, e.g., by sonication. A preferred help layer material is a water-soluble polymer, such as polyvinyl acetate.

[0108] Thus, in this process, an auxiliary layer is first applied to the substrate and optionally cured. The material of the top layer of the device, i.e., the adhesive layer, is then applied to this auxiliary layer and cured. Further layers are then applied depending on the nature of the device to be produced. These may be further flexible or support layers. The layers may be cured in either case. The microstructure is then applied. As mentioned above, it may be necessary to apply an uncured layer beforehand, which is only cured after the application of the microstructure. The auxiliary layer is then selectively dissolved and the device is removed. It may also be necessary to clean the surface to remove any residue of the auxiliary layer.

[0109] In one embodiment of the present invention, instead of the auxiliary layer, a particularly easily removable material is used as the substrate of the first layer. In this case, a material with a fluorinated silicone or fluorinated silane coating is preferred, an example of which is a release liner. The material in question can include, for example, a film with such a coating.

[0110] The release liner must have a very smooth surface since any irregularities will be replicated on the top layer.

[0111] Further details and features are evident from the following description of preferred exemplary embodiments in conjunction with the dependent claims. In these contexts, each feature can be realized alone or in multiple combinations with one another. The possibilities for achieving the objective are not limited to the exemplary embodiments. For example, range indications always include all unstated intermediate values ​​and all possible subintervals.

[0112] Exemplary embodiments are represented diagrammatically in the drawings, in which identical reference numbers in the individual figures indicate identical or functionally identical elements or elements that correspond to one another in terms of their functionality. [Brief explanation of the drawings]

[0113] [Figure 1] 1 shows an outline of the manufacturing process for the film end adhesive structure. [Figure 2] (A) Overview of sample A at low magnification in a plan view. The bottom arrow indicates an upright pillar, and the orange arrow indicates several fallen pillars. (B) Overview of sample A at higher magnification in a plan view, showing fallen pillars in close proximity (upper arrow). (C) Schematic of a cross section of sample A at high magnification, where the dissolving layers of the substrate (adhesive layer and glass substrate) serve only for fixation. Schematic of sample A, with MDX-4 shown in gray. (D) Size order indicated; all lengths are in μm. Scale is 500 μm for A, 100 μm for B and C. [Figure 3] (A) Schematic of sample B at low magnification in plan view, with arrows pointing to voids caused by fallen pillars. (B) Overview of sample B at higher magnification in plan view - arrows point to irregularities and impurities on the surface; (C) Schematic of the cross section of sample B at high magnification. Schematic of sample B, with MDX-4 shown in gray. (D) Size order indicated; all lengths are in μm. Scale is 500 μm for A, 100 μm for B and C. [Figure 4]SEM micrographs of the samples are shown. A sample: only the microstructured part is shown (A). B) B sample is shown where an end film made of the same material as the microstructured part was applied as a support layer (B). * indicates the end layer. C) C sample is shown after application of a flexible skin adhesive layer (C). * indicates the boundary layer between the two layers. D) The bottom surface of the end layer is visible (D). [Figure 5] C shows the cross section of the sample. [Figure 6] The cross sections of the different B samples are shown. The thickness of the termination layer can be adjusted in a defined manner by spin coating. A spin coating speed of 800 rpm (A) results in a layer thickness of 60.5 μm, 2000 rpm (B) results in a layer thickness of 31.3 μm, and 9000 rpm (C) results in a layer thickness of 12.2 μm. The layer thickness can also be further reduced by adding a solvent to the polymer. [Figure 7] Various microstructured samples and flat reference samples of comparable thickness and structure are shown: A) A sample with a backing layer and microstructures, and A reference sample; B) B sample with a backing layer, microstructures, and support layer, and B reference sample with a base and support layer; C) C sample with a backing layer, microstructures, support layer, and "bonding layer," and C reference sample with a base, support layer, and "bonding layer" (in each case, from bottom to top). [Figure 8] Figure 7 and Table 1 show the stress and desorption energy (work) of the samples (holding time 1 s). [Figure 9] Rheological measurements of various samples are shown. [Figure 10] 1 shows the fabrication of film end pillars without a support layer. [Figure 11] FIG. 1 shows a schematic diagram for using an adhesive system with a separable film. [Figure 12] 1 illustrates an exemplary embodiment of an adhesive system using a separable film. [Figure 13] Schematic diagram of peel measurement is shown. [Figure 14] 1 illustrates an embodiment of a manufacturing process for an adhesive system. [Figure 15] 1 shows a schematic diagram of a measurement device used to determine adhesion values. [Figure 16] An exemplary diagram of a stress-time curve (left) and a stress-displacement transfer curve is shown. [Figure 17] Photographs of the microstructure after demolding (A) and after mechanical processing (B) are shown. [Figure 18] 1 shows a light microscope photograph of one embodiment of the present invention. [Figure 19] 1 shows the peel measurements at different removal rates. [Figure 20] 1 shows measurements of vibration characteristics of the mouse eardrum. DETAILED DESCRIPTION OF THE INVENTION

[0114] Figure 1 shows an overview of the process for producing a film end adhesive structure. The finished adhesive system consists of a microstructured part (101) made of Silastic MDX4-4210 and an end film, here consisting of a combination of layers of MDX4-4210 (102, 103, step III.ai) followed by the application of a skin-adhesive end layer MG7-1010 (104, VI.ai). The end layer can also be produced without the MDX4 support layer, as shown in III.bi. Each step is described below. The material and thickness of each layer or structure can be varied by changing the materials or application conditions.

[0115] I. Wafer Modeling The wafer (silicon wafer) is placed in a Petri dish and filled with the material for the microstructure mold (PDMS, Elastosil 4601, Wacker, Riemerling, Germany, 100). After degassing, a glass plate (111) is placed on top and cured at 75°C for at least 3 hours. The cured mold (100) is then removed. The wafer now contains the microstructure.

[0116] The resulting mold was silanized with fluorosilane (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, 50 μL solution) under reduced pressure (20 mbar).

[0117] II. Fabrication of microstructured parts in adhesive systems For the microstructure material, two components (Silastic MDX4-4210) are weighed and mixed in the ratio A:B (10:1). This material was used for all structures and layers of Silastic MDX4-4210.

[0118] The mold (100) is placed on a glass plate (111) and filled with the material for the microstructure. The surface is flattened by spin coating (3000 rpm, 120 seconds), which gives a small overlay to the filled mold. Degassing may be necessary before spin coating.

[0119] In parallel, a backing layer (Silastic MDX4-4210) is applied to a plasma-activated glass plate. A layer with the specified thickness is produced by spin coating (9000 rpm, 120 seconds). The plasma-activated glass plate thus coated is then applied to the filled microstructure. The structure is rotated 180° and placed on a plasma-activated glass plate (112, oxygen-argon plasma, 2 minutes) and cured (95°C, 1 hour). This connects the microstructure to the backing layer. To effectively separate the cured microstructure from the mold, oxygen-argon plasma is used to achieve effective bonding of the structure to the glass plate.

[0120] This structure is applied to a new glass plate (111). It may be necessary to align the pillars of the microstructure by mechanical action, such as brushing or combing (Figure 17). This results in the A sample, i.e., a microstructure without an end film. The separate production of the backing layer allows its thickness and material to be easily adapted.

[0121] Figure 2 shows the micrographs (A, B, C) and a schematic diagram of sample A. The microstructure was also used for other experiments.

[0122] As a reference sample, a film of the same material and of comparable thickness is prepared via a doctor blade.

[0123] III.ai Preparation of the support layer The material for the outer layer (Silastic MDX4-4210, 103) is applied to a glass plate (111) and distributed by spin coating (9000 rpm, 180 seconds). The coating is cured at 95°C for one hour. The material for the support layer (Silastic MDX4-4210, 102) is then applied and distributed by spin coating (9000 rpm, 180 seconds). The manufactured microstructure (101) with pillars is then placed on the applied layer that has not yet been cured, so that the pillars are at least in contact with the last applied layer. The whole is then cured at 95°C for one hour. The resulting structure (sample B) is rotated 180° and a backing layer is applied to the glass plate.

[0124] FIG. 3 shows a micrograph of sample B.

[0125] For the reference sample, the material of the reference structure (Silastic MDX4-4210) is applied to a glass plate, for example using a doctor blade. The thickness is the same as that of the microstructure. To this layer, the material of the bottom layer (Silastic MDX4-4210) is applied, which is distributed by spin coating (9000 rpm, 180 seconds) and the whole is cured at 95°C for 1 hour. The material of the second layer (Silastic MDX4-4210) is applied to this layer, which is distributed by spin coating (9000 rpm, 180 seconds) and the whole is cured at 95°C for 1 hour.

[0126] III. Preparation of end films without a supporting layer The fabrication is illustrated diagrammatically in Figure 10. The material for the auxiliary layer (120, 20% PVA polyvinyl acetate in H2O) is applied to a glass plate (111), dispensed by spin coating (3000 rpm, 60 seconds), and cured at 95 °C for 10 minutes. The material for the adhesive layer (106, Dow Corning MG7-1010) is then applied by spin coating (4000 rpm, 120 seconds, 100 rpm / s), and cured at 95 °C for 1 hour. The material for the further adhesive layer (105, Dow Corning MG7-1010) is then applied by spin coating (9000 rpm, 180 seconds). The fabricated microstructure (101) with pillars is then placed on the applied layer (105) that has not yet been cured, with the pillars at least in contact with the layer. The whole is then cured at 95 °C for 1 hour. The sample is then cut to size as needed. The auxiliary layer (120) is then selectively dissolved in water (ultrasonic bath for 10-20 minutes). The detached composite structure is applied to a glass plate together with the backing layer and allowed to dry. This results in a B-OS sample. The adhesive layer had an average thickness of 27 μm. A 70 μm thick B-OS sample was also prepared.

[0127] For the reference sample, the material of the reference structure (Silastic MDX4-4210) is applied to a glass plate, for example using a doctor blade. The thickness is similar to that of the microstructure. To this layer, the material of the bottom layer (Dow Corning MG7-1010) is applied, distributed by spin coating (1000 rpm, 120 seconds), and the whole is cured at 95°C for 1 hour. To this layer, the material of the second layer (Dow Corning MG7-1010) is applied, distributed by spin coating (9000 rpm, 180 seconds), and cured at 95°C for 1 hour.

[0128] The process using the auxiliary layer can also be used to fabricate the C sample when the microstructure with the end film is in place.

[0129] IV ai Preparation of the final adhesive layer The viscoelastic layer was prepared by mixing viscoelastic material MG7-1010 (Dow Corning, Midland, USA). The two components were weighed and mixed in a 1:1 ratio.

[0130] Adhesion layer material (104, Dow Corning MG7-1010) was applied to the III.ai structure, distributed by spin coating (4000 rpm, 120 seconds), and cured at 95° C. for 1 hour, resulting in the C sample.

[0131] Figures 4, 5 and 6 show photographs of the different samples. Measurements were performed using sample C with the following values: backing layer: 71.99 + / - 25.16 μm, microstructure height 208.44 + / - 18.87 μm, support layer thickness (102, 103): 19.7 + / - 4.94 μm, adhesive layer: 21.25 + / - 12.05 μm.

[0132] Table 1 and Figure 8 show the adhesion stress and work of various samples (Figure 7) determined in tack tests on substrates that model the roughness of skin. Determination of adhesion stress and detachment energy for various microstructured samples compared to unstructured samples with comparable layer structures. It is clear that the microstructured samples not only have higher adhesion stress but also higher work relative to the rough substrate.

[0133] Table 4 shows the results for different roughness (R z Table 3 shows the adhesive stress (1 s hold time) measured for various samples on substrates with a rough surface. Table 3 shows the same data, with the values ​​for the smooth substrates set to 100% in each case. It is clear that the samples with adhesive layers (C, BoS) lose much less adhesion in the case of rough substrates. Samples manufactured with auxiliary layers or release liners have better adhesion values ​​than the samples in Table 1, since these processes provide better surface flatness for the adhesive layer.

[0134] FIG. 11 shows an adhesive system with a separable end film. This system consists of two components: an end film (I) and a microstructured part (II, 101), which are manufactured separately and then pressed together in step 1. The layer configuration of the three-layer end film is as follows: an adhesive layer (131, Dow Corning MG7-1010), an elastic support layer (132, Silastic MDX4-4210), and an adhesive layer (132, Dow Corning MG7-1010). In a second step, the adhesive system can be used and applied to a rough surface (134, e.g., skin). During use, the bottom layer 132 becomes dirty. Because the connection between the microstructure 101 and the inner adhesive layer 131 is reversible, the microstructure and the film can be separated from each other. In this case, the end film is discarded, but the microstructured part can be returned to the product's life cycle. It is also possible to apply the end film to a microstructure that already has a support layer applied. This process allows for the reuse of microstructures that are expensive and complex to manufacture.

[0135] Figure 12 shows an exemplary embodiment of an adhesive system with a separable film. The film was produced by triple spin-coating of various materials. The terminal film (A) was made from adhesive layers (131, 132) and a support layer (130). Figure 12 shows a light microscope image of the cross section of the film. The two adhesive layers (MG7-1010) appear darker, while the middle support layer (MDX4-4210) appears lighter. The thickness is 32.32 μm. The film itself is applied to glass. This film was applied to different structures (C, Sylgard 184 with microstructure thickness, Tesafilm, microstructure of Sylgard 184 film) and used for peel measurements (D, see Figure 13, 180°, 1 mm / step, maximum measured force divided by sample width). It is clear that this system allows for the advantages of the inventive system while the film remains removable.

[0136] FIG. 18 shows a light microscope photograph of the removable film (top) on the microstructure.

[0137] Figure 19 shows the maximum force measured for different backing systems applied to the film. The pillars are microstructures made of Sylgard 184 (protrusion height: 187 ± 1.5 μm, backing layer: 62 ± 4 μm), and the tape is Tesafilm (thickness: 59 ± 1.3 μm). Sylgard 184 is a film of Sylgard 184 (thickness: 295 ± 8.4 μm).

[0138] For the measurement of a removal rate of 0.5 mm / step (top), the film was measured with the following structure: MG7-1010: 30±4.5 μm / MDX4-4210: 25±5 μm / MG7-1010: 33±7 μm. The measurement was performed three times.

[0139] Measurements of removal speed 1 mm / step (bottom) were performed on films with the following composition: MG7-1010: 28 ± 3.5 μm / MDX4-4210: 22 ± 4.5 μm / MG7-1010: 27 ± 4 μm. Measurements were performed three times.

[0140] Figure 13 shows a schematic diagram of the peel measurement. A backing 143 is applied to a hexapod 144. A substrate 142 is applied in a vertical area. The substrate used had an elasticity similar to that of skin. Additionally, modeling of an artificial skin (Vitroskin) was performed to obtain a replica of human skin. The substrate under test is attached to a strip 141 connected to a load cell 140 that can be pulled apart parallel to the surface while the force is measured. The measurement parameters used were: hold time: 60 seconds; removal direction 180°, removal speed 1 mm / step, preload: 1.1 kPa (area 0.75 x 0.75 cm). Different substrates were measured. The measurements shown in the figure were performed using a model of Vitroskin (Turboflex) (R a = 4.43 μm, R z = 25.3 μm). The strip width was 6.5 to 7 mm. The measurement length depended on the substrate and was up to 7 mm.

[0141] FIG. 14 shows a further embodiment of a process for producing an adhesive system. In this case, the adhesive layer 132, which will later become the outermost layer, is applied to a release liner (fluorinated 135, step I, 3M Scotchpak 9709 release liner film, fluorosilicone-coated polyester film). Based on this, further layers, such as adhesive and support layers, can be applied according to the desired embodiment, and then the microstructures are applied to these layers. The layers can be produced by spin coating and curing, as in the processes already described. To apply the microstructures 101, the last applied layer with the applied microstructures is cured, or the last applied layer is an adhesive layer. FIG. 14 shows the application of the support layer 130 as step II. To this layer, an adhesive layer 131 is applied (step III). To this layer, the microstructures 101 are applied (step IV). In alternative Ia, the microstructures 101 are applied directly or after the application of further adhesive layers (105, 106). For different materials, it may be necessary to treat the surface with air plasma before applying the next material. In this way, it is possible to prevent the soft layer in particular from changing its properties due to successive curing steps.

[0142] The release liner 135 allows for easy and damage-free removal of the adhesive system, reducing production time and improving the quality of the system.

[0143] If a microstructure with a terminal film is placed, a process using a release liner can also be used to manufacture sample B. An alternative possibility is to apply one or more MDX4-4210 layers as the last layer, which are then connected to the microstructure as described above. For better attachment of the MDX4-4210 layer, it may be necessary to carry out a plasma treatment (air plasma) before application to improve attachment.

[0144] The use of a release liner allowed achieving a more uniform surface of the sample, leading to a further improvement in adhesion. During half the holding time, the BoS sample (with the same microstructure and an adhesive layer thickness of 30 μm) exhibited 641 ± 79 mJ / m 2 and a stress of 14.84±1.18 kPa, while the reference is 79.03±39.91 mJ / m 2 and 7.25±3.04 kPa. With increasing holding time, the desorption energy increases more than twice, more specifically by 56%, for the BOS sample. The cohesive stress shows an increase of 35%. For the BoS-Ref sample, an increase of 61% in the desorption energy and 33% in the cohesive stress can be measured.

[0145] Rheometric data were measured using a rheometer (MCR 300, Anton Paar (formerly Physica), Graz, Austria). The rheometer has a cone-plate geometry. Before the measurements were carried out, small amounts of polymer mixtures were prepared in each case. MG7-1010, MDX4-4210, and Sylgard 184 in a 10:1 ratio and Sylgard 184 in a 100:1.6 ratio were tested. The latter two mixtures are comparative mixtures, which have been used in the literature for microstructure analysis. Each sample was measured three times and was prepared fresh for this purpose.

[0146] Figure 9 shows a graphical evaluation of the rheometry measurements (A: storage modulus (G'), B: complex modulus (G*), C: loss modulus (G"), D: damping coefficient (tan δ = G" / G')).

[0147] The elastic modulus can be estimated for each material using the storage modulus. These values ​​differ from those measured with a nanoindenter, but give a relative ratio.

[0148] Based on the assumption of E ~ 3 * G', the values ​​reported in Table 2 are obtained for 1 Hz. These values ​​also show that Sylgard 184 10:1 is much harder than MDX4-4210, which corresponds to measured nanoindenter values ​​of 2.7 MPa and 1.9 MPa, respectively (steel hemisphere, sample thickness > 1 mm, sample indentation depth 5000 nm).

[0149] Figure 15 shows the schematic configuration of the measurement device for determining adhesion values. In the figure, s represents the position of the platform in the z direction. The platform moves in the positive z direction to bring the sample into contact with the substrate. Once a specified compressive prestress is reached, the position is maintained for a specified holding time. Measurement variables, such as the induced force, are detected by a load cell and can be read from a screen. The sample is fixed by the bonding substrate on a glass slide, which is fixed on the platform using a screw device on the sample mount. To change the sample position, the platform, along with the sample, can also be displaced in the x and y directions. The sample position and contact can be observed and adjusted using optical elements such as a prism and cameras 1 and 2.

[0150] The platform was moved in the positive z-direction towards the substrate at a rate of 30 μm / s until the established compressive prestress was 70 ± 20 mN (or 10 ± 4 kPa). After contact between the sample and the substrate was maintained for a defined holding time of either 1 s or 30 s, the sample was detached from the substrate. For this, the platform was moved in the negative z-direction at a removal rate of 10 μm / s. The measurement setup included a load cell (maximum 3 N, Tedea-Huntleigh 1004, Vishay Precision Group, Basingstoke, GB) oriented to capture low detachment forces. The system measured the time t and the platform position s. zThe induced normal force F in the z-direction relative to the sample was recorded. A prism was integrated into the sample mount for optical detection of the sample position and thus for observation of the contact between the sample and the substrate. This allowed the measurements to be tracked and recorded on a computer screen with the help of two cameras (camera 1 and 2) (DMK23UX236, The Imaging Source, Germany). A goniometer was used to adjust the contact area between the sample and the test substrate.

[0151] FIG. 16 shows exemplary diagrams of stress-time curves and stress-displacement transfer curves. The maximum of each of the curves indicates the selected compressive prestress, in other words the stress at which the sample is pressed against the test substrate. The minimum of the curves in each case indicates the cohesive stress (σ s ) The area encompassed by the curve and the zero line of the stress-displacement diagram corresponds to the desorption energy (W deb The area of ​​each test substrate was determined by optical microscopy. The detachment operation is initiated, but the sample and substrate are still in full contact with each other, and at time t0, the compressive prestress passes through zero, and the platform s z The position of is called s0 (Figure 16). end is the time when the desorption operation is completed (s end ), which is the point at which the adhesive stress equals zero.

[0152] The test substrates used were as follows: a model of smooth glass (polished glass) in epoxy resin (EGS area 6.2 mm 2 , R a =0.01μm, R z = 0.10 μm), a rough glass (etched matte glass) model in epoxy resin (EGR area 6.95 mm 2 、 R a =0.22μm, R z = 1.97 μm), and a model of Vitroskin made from epoxy resin (area 7.26 mm 2、 R a = 9.48 μm, R z = 49.66 μm). A mouse eardrum model was also used. For these models, R z = 2.2 μm (tension part) and R z It was possible to determine a roughness depth of 13 μm (relaxed area). All Ra and Rz values ​​were measured using a profilometer (SURFCOM 1500SD3, Carl Zeiss, Oberkochen, Germany). Ra and Rz were determined according to DIN EN ISO standard 4287:2010-07.

[0153] The curvature of the tympanic membrane at the tension point is 35.33±3.5° (measured by optical microscope). However, when used on the tympanic membrane, excessively good adhesion may also be detrimental to detachment due to the high sensitivity of the tympanic membrane. In the case of the device of the present invention, adhesion can be adjusted in a simple manner by changing the parameters.

[0154] Figure 20 shows the vibration characteristics of mouse tympanic membranes (intact, perforated, perforated with a simple film, and perforated with microstructures).

[0155] Distortion product otoacoustic emissions (DPOAEs) were measured in anesthetized female mice aged 6 to 8 weeks. The strain was CBA / J. The investigated frequency range was 8 kHz to 17.9 kHz. Flat films and microstructured systems with a diameter of approximately 1 mm were used. The diameter of the perforations was 0.5 to 0.9 mm.

[0156] The microstructures used had a 20 μm adhesive layer without a support layer, protrusions 20 μm in diameter and 40 μm high, and a backing layer 20–50 μm thick. The minimum distance between pillars was 20 μm. They had a regular hexagonal arrangement.

[0157] The results show that the inventive film does not have any adverse effects. For a given weight, the inventive microstructure is somewhat bulkier than the unstructured film. This microstructure is inherently significantly more stable and can be applied with greater precision.

[0158] [Table 1]

[0159] [Table 2]

[0160] [Table 3]

[0161] [Table 4] [Explanation of symbols]

[0162] 100 Microstructure mold (Elastosil 4601) 101 Microstructure (Silastic MDX4-4210) 102 Support layer (Silastic MDX4-4210) 103 layers (Silastic MDX4-4210) 104 Adhesive layer (Dow Corning MG7-1010) 105 Adhesive layer (Dow Corning MG7-1010) 106 Adhesive layer (Dow Corning MG7-1010) 110 wafers 111 Glass Plate 112 Plasma activated glass plate 120 Auxiliary layer 130 Supporter layer 131 Adhesive layer 132 Adhesive layer 133 Dirt 134 Rough surface (skin) 135 Release liner 140 load cells 141 Strip 142 PCB 143 Backing (glass) 144 Hexapod

Claims

1. A device with a structured coating for adhering to a rough surface, said device comprising a backing layer with a number of protrusions including stems having at least in each case end faces pointing away from the surface, said end faces having at least one further layer configured as a film, said layer consisting of at least one layer having a lower modulus of elasticity than each of said protrusions, The device, characterized in that the additional layers include, starting from the edge surface, a low modulus layer for bonding to the edge surface, a support layer, and an even lower modulus layer for adhering to the roughened surface.

2. The device of claim 1 , wherein the protrusions have an aspect ratio greater than one.

3. 3. The device of claim 1, wherein the protrusions have an aspect ratio of at least 1.

5.

4. The device according to any one of claims 1 to 3, characterized in that the further layer with the lower modulus is removable from the device.

5. The device according to any one of claims 1 to 4, characterized in that it is adapted to adhere to living tissue.

6. 6. The device of claim 5 for use in treating a tympanic membrane perforation.

7. An implant comprising a device according to any one of claims 1 to 6.

Images