Method for producing semi-finished products for medical purposes

Abstract

The invention relates to a method for producing semi-finished products (10) for medical purposes, the method having the following steps: a) providing a plurality of rotation units (20) each having a cylindrical, internal deposition surface (21), b) rotating the rotation units (20) in each case about an axis of rotation associated with the rotation unit (20), c) introducing a semi-finished material (11) via injection units (30) into the rotating rotation units (20) such that the semi-finished material (11) is deposited onto the inner circumferential surfaces (21), in particular over the entire surface, of the respective rotation units (20) under the action of a centrifugal force, d) curing the semi-finished material (11) while rotating the rotation units (20) in order to form the semi-finished product (10), and e) removing the semi-finished products (10) from the rotation units (20), wherein in step c) a feed amount of the semi-finished product (11) is set such that the tubular semi-finished products cured by step d) each form a continuous cylindrical, in particular smooth, inner circumferential surface.

Description

[0001] - 1 - University of Stuttgart (Public Corporation)

[0002] Method for the production of semi-finished products for medical purposes. The invention relates to a method for the production of semi-finished products for medical purposes. Furthermore, the invention relates to a valve prosthesis, which is produced in particular from semi-finished products manufactured using this method.

[0003] Tubular semi-finished products, mostly made of polymers, are used in various medical applications. These semi-finished products, especially thin-walled ones, are required in particular for the production of catheters, thrombectomy systems, heart valves, but also stents and flow diverters or stent covers, which are thus referred to as stent grafts.

[0004] For example, stents can be manufactured by first providing a polymer tube as a semi-finished product, which is then laser-cut to create openings, forming a lattice structure that can be inserted into a blood vessel as a stent. To create a stent graft, a polymer tube is connected to an existing stent.

[0005] Currently, such semi-finished products are mostly manufactured using injection molding or extrusion processes. These established methods have several disadvantages. In particular, both processes require a relatively high temperature to melt the semi-finished material. This necessitates a relatively high energy expenditure. Furthermore, some materials that would be suitable for treatment within the human body cannot be used because they cannot withstand such temperatures. This includes, in particular, biopolymers that cannot tolerate high temperatures or are dissolved in solvents that cannot be produced using the aforementioned manufacturing technologies.

[0006] Another disadvantage is that the tolerances in conventional manufacturing processes are comparatively large. With injection molding, this is further complicated by the fact that small irregularities often form in the injection area, requiring extensive post-processing to prevent the finished implant from posing a risk of injury. A significant disadvantage of conventional manufacturing processes is also the limited availability of different UNS-21528-P-WO- 2 - University of Stuttgart KdöR

[0007] Materials for the formation of semi-finished products with multiple material layers are difficult to obtain.

[0008] The object of the invention is therefore to provide a method for manufacturing semi-finished products for medical purposes that produces highly precise semi-finished products with low tolerances in an industrially usable and energy-saving manner and expands the design possibilities for such semi-finished products. Furthermore, it is an object of the invention to provide a valve prosthesis formed from a semi-finished product manufactured in this way.

[0009] According to the invention, this problem is solved with regard to the manufacturing process by the subject matter of claim 1 and with regard to the

[0010] The flap prosthesis is solved by the subject matter of claim 16.

[0011] The invention is based on the idea of ​​specifying a method for the production of semi-finished products for medical purposes, wherein the method comprises the following steps:

[0012] a) Providing several rotating units, each with a cylindrical, internal separation surface,

[0013] b) Rotating the rotation units around one of the rotational axes assigned to the respective rotation unit,

[0014] c) Introducing a semi-finished material via injection units into the rotating units, so that the semi-finished material is deposited under the influence of a centrifugal force, in particular over the entire surface, on the inner depositing surfaces of the respective rotating units,

[0015] d) Curing of the semi-finished product material under rotation of the respective rotational units to form the semi-finished product, and

[0016] e) Removal of semi-finished products from the rotary units,

[0017] UNS-21528-P-WO- 3 - University of Stuttgart (KdöR)

[0018] wherein in step c) the quantity of semi-finished material is adjusted so that the tubular semi-finished products hardened by step d) each form a continuously cylindrical, in particular smooth, inner circumferential surface.

[0019] In contrast to conventional injection molding or extrusion processes, the invention produces semi-finished products for medical purposes by depositing the semi-finished material onto an internal deposition surface of a rotating unit using centrifugal force. This centrifugation process offers several advantages. Firstly, it allows for particularly tight tolerances. In particular, very thin-walled semi-finished products can be manufactured with high precision. Furthermore, it is possible to change the semi-finished material during production, enabling the creation of multi-layered semi-finished products made from different materials. Secondly, the process according to the invention facilitates serial production on an industrial scale by providing multiple rotating units. This allows for the simultaneous production of several semi-finished products.However, it is not impossible that the production of semi-finished products takes place at different times in the individual rotation units, so that essentially a continuous output of semi-finished products is achieved.

[0020] The process according to the invention can also be carried out with a single rotary unit for the production of a single semi-finished product. Step a) of the process can therefore be implemented by providing at least one rotary unit with a cylindrical, internal deposition surface, wherein all subsequent process steps are also carried out with a rotary unit.

[0021] Therefore, the procedure can consist of the following steps:

[0022] a) Providing at least one rotating unit with a cylindrical, internal separation surface,

[0023] b) Rotating the at least one unit of rotation about an axis of rotation assigned to the unit of rotation,

[0024] UNS-21528-P-WO- 4 - University of Stuttgart (KdöR)

[0025] c) Introducing a semi-finished material into the rotating unit via at least one injection unit, so that the semi-finished material is deposited on the inner depositing surface of the rotating unit under the influence of a centrifugal force, in particular over the entire surface,

[0026] d) Curing of the semi-finished product material under rotation of the rotary unit to form the semi-finished product, and

[0027] e) Removal of the semi-finished product from the rotary unit,

[0028] wherein in step c) the quantity of semi-finished material is adjusted so that the tubular semi-finished product hardened by step d) forms a continuously cylindrical, in particular smooth, inner circumferential surface.

[0029] Where several rotary units and / or injection units are mentioned below, this also applies analogously to the production of a single semi-finished product using a rotary unit and an injection unit.

[0030] The dimensions of the semi-finished products cured after step e), in particular their wall thickness, can be selected based on specifications for the medical implants to be manufactured from these semi-finished products. For example, the wall thickness of the semi-finished product can be set between 40 pm and 300 pm if it is intended for the production of a vascular implant, especially a stent, with a cross-sectional diameter between 2 mm and 10 mm. If the semi-finished product is intended for the production of a vascular prosthesis with a cross-sectional diameter between 2 mm and 6 mm, which will be surgically sutured to biological tissue, for example, a wall thickness between 500 pm and 2 mm can be set during the manufacturing process. A wall thickness of the semi-finished product between 40 pm and 300 pm, and in particular between 50 pm and 150 pm, is advantageous if the semi-finished product is intended for the production of a flexible film as a valve leaflet for a heart valve with a diameter between 10 mm and 25 mm.

[0031] In a preferred embodiment of the method according to the invention, the rotational units each have a dimensionally stable rotating mold and a negative mold, preferably elastic. The negative mold is preferably in the UNS-21528-P-WO- 5 - University of Stuttgart KdöR

[0032] The rotating mold is arranged and forms the inner depositing surface. In other words, the individual rotating units can be composed of several components. The outer rotating mold forms a dimensionally stable part in which the inner negative mold is inserted. The negative mold is preferably elastic and forms the cylindrical, inner depositing surface onto which the semi-finished material is centrifugally deposited. The elasticity of the negative mold ensures that the semi-finished product can be easily removed from the mold after curing.

[0033] The negative mold can be inserted into the rotary mold as a type of insert. The negative mold is removable from the rotary mold and preferably elastic, in particular made of silicone and / or polydimethylsiloxane, to allow the manufactured semi-finished product, especially a flexible film or tube, to be demolded without damage after step d) or in step e). Alternatively, the negative mold can be destroyed to demold the semi-finished product, for example, by breaking it at predetermined breaking points.

[0034] It is also possible that the negative mold is dimensionally stable. It can be modular in design to allow for the removal of the semi-finished product in step e). Alternatively, the semi-finished product can be inserted directly into the dimensionally stable rotary mold without the use of a negative mold. In this case, the inner wall of the rotary mold constitutes the deposition surface.

[0035] Generally, it is advantageous if the rotary mold is made of a stable material, such as a metal. Alternatively, the rotary mold can be made of glass, preferably transparent glass. This allows for visual monitoring of the deposition process.

[0036] The semi-finished material can have plastic and / or elastic properties. The semi-finished material is preferably a polymer. Biopolymers can also be used. It is also possible to use a hydrogel as the semi-finished material. Hydrogels can be cured by crosslinking agents. Alternatively, the hydrogel can be cured by a temperature change, in particular by a reduction of the UNS-21528-P-WO- 6 - University of Stuttgart KdöR

[0037] Temperature during the injection of the semi-finished product material into the rotating unit.

[0038] In general, it is also possible to use porous materials, such as foams, as semi-finished products. The porosity can be created by the formation of gases within the semi-finished product during curing.

[0039] The aforementioned semi-finished materials can also be combined with one another. This can be achieved in particular by sequential deposition in the rotary unit, so that the semi-finished product is formed from several layers of different semi-finished materials.

[0040] In general, the semi-finished material can be introduced into the individual rotary units via injection units. Each injection unit can have injection needles, which are inserted into the respective rotary unit through an end face. Introducing the semi-finished material into the rotary unit, particularly the negative mold, via an injection needle allows for a high degree of control over the deposition process. The injection needle can be inserted coaxially to a longitudinal axis of the rotary unit through the end face, or eccentrically. It is advantageous if the injection needle does not touch the cylindrical inner deposition surface on which the semi-finished material is deposited. The tip of the injection needle, from which the semi-finished material emerges, should instead remain suspended within the rotary mold.

[0041] To achieve a uniform and well-distributed deposition of semi-finished material along the length of the rotating unit, it is advantageous if the injection needles in the individual rotating units are longitudinally displaceable relative to the rotating units. Crucially, this requires relative movement between the respective rotating unit and its associated injection needle. It is irrelevant whether the rotating unit and / or the injection needle is moved. In any case, the relative movement between the rotating unit and the injection needle ensures that the semi-finished material is distributed evenly over the length of the rotating unit, particularly over the length of the negative mold. UNS-21528-P-WO- 7 - University of Stuttgart

[0042] This ensures that the entire cylindrical, internal deposition surface can be covered. Therefore, the relative movement between the rotating unit and the injection needle preferably occurs in a continuous motion or in discrete steps.

[0043] It is particularly advantageous if the rotary units and the injection units interact in such a way that steps c) to d) are performed simultaneously in all rotary units. Additionally, step b) can also be performed simultaneously in all rotary units. Alternatively, the rotary units and the injection units can interact in such a way that steps c) to e) are staggered, so that a semi-finished product is completed at regular intervals. In this way, a continuous manufacturing process can be achieved. Both of the aforementioned variants have the advantage that series production can be achieved at comparatively low costs and with minimal time expenditure.

[0044] A further advantageous embodiment of the method according to the invention provides that in step c) the semi-finished material is expelled from the injection needle by a conveying device and / or the injection needle is moved longitudinally through the rotating unit by a propulsion device. The conveying device can preferably be controlled such that the semi-finished material is continuously expelled from the injection needle. Likewise, the propulsion device can be controlled such that the injection needle is moved continuously, with a uniform motion, or in defined, in particular discrete, steps through the rotating unit. This ensures that semi-finished products with a high degree of material and dimensional homogeneity are produced.

[0045] It is further preferred if, in step c), the semi-finished material is introduced into the rotary units from a common semi-finished material storage area, in particular by means of one or more conveying devices. The use of a common semi-finished material storage area facilitates the provision of semi-finished material and thus the handling of the process. Furthermore, reference is made to this

[0046] UNS-21528-P-WO- 8 - University of Stuttgart (KdöR)

[0047] This ensures that all semi-finished products manufactured in parallel or serially have essentially the same properties.

[0048] At least some, and in particular all, of the rotating units can be moved by a common rotary drive. Alternatively or additionally, at least some, and in particular all, of the injection needles can be moved by a common propulsion device. Furthermore, alternatively or additionally, the semi-finished product material can be conveyed through the injection needles by means of a common conveying device. To utilize the process described here as efficiently as possible, the individual moving parts of a device for implementing the process can each be combined with common drive units in order to reduce the number of components required and increase ease of maintenance. For example, all rotating units can be driven by a common rotary drive.This has the further advantage of ensuring coordinated movement, particularly uniform rotation, especially with regard to rotational speed, of the individual rotating units. Similarly, the injection needles can be moved by a common propulsion device to ensure uniform movement. Likewise, the conveying of the semi-finished material through the injection needles can be achieved using a common conveying device, thus ensuring a uniform and consistent expulsion of the semi-finished material from the injection needles.

[0049] Alternatively, it is conceivable that the rotary units are each moved by individual rotary drives and / or the injection units by individual thrust devices. The semi-finished material can alternatively or additionally be conveyed by individual conveying devices, each assigned to a specific injection needle. When using individual rotary drives, individual thrust devices, and / or individual conveying devices, it is preferred if the rotary drives and / or thrust devices and / or conveying devices are actuated by a common control system. It is further preferred that the aforementioned actuation is synchronized. A uniform movement of the rotary units and / or UNS-21528-P-WO- 9 - University of Stuttgart KdöR

[0050] In this case, the injection units, or rather the uniform conveying of the semi-finished material through the injection needles, are achieved by synchronizing the individual drives. Such synchronization can be implemented electrically and / or electronically. It is also possible for the individual drives mentioned above to be actuated via a preferably digital control interface, which displays an overview of the current operational status of individual rotary drives, individual propulsion units, and / or individual conveying units. Thus, the aforementioned drives can be actuated individually or synchronously, particularly simultaneously or with a time delay, via command functions, especially by selecting a graphical window.Regarding the common rotary drive or the individual rotary drives, it is generally the case that these can be adapted such that the rotary units, in particular rotary molds, can be rotated at a speed between 500 rpm and 10,000 rpm, preferably between 1,000 rpm and 8,000 rpm, and particularly between 2,000 rpm and 5,000 rpm. It is provided that the imbalance of each individual rotary unit, in particular of each individual rotary mold with a negative form, is limited in order to produce a semi-finished product with a thickness variation along the circumference of the semi-finished product. The thickness variation can be small. The thickness variation (in the circumferential direction) can be less than 10%, in particular less than 5%, and in particular less than 2%. The imbalance in each rotary unit can be measured by a laser system. Alternatively, the imbalance can also be measured using an infrared system.The measurement data can be used to adjust the negative mold and / or the rotary mold, or to correct any existing imbalance.

[0051] Generally, the connection from the rotating unit(s) to the rotary drive is preferably made via a drive shaft with high bending resistance to avoid imbalances. To further prevent imbalance, the rotating unit can be mechanically supported and thus centered relative to a drive shaft of the rotary drive. The support is preferably located on the side opposite the drive shaft.

[0052] UNS-21528-P-WO- 10 - University of Stuttgart (KdöR)

[0053] particularly on the side where the end face opening for supplying the semi-finished material is formed. The drive shaft can additionally be supported at at least one point, preferably two points, and thus axially aligned. Ball and plain bearings can be used for supporting the rotating unit and / or the drive shaft. It has been shown that the aforementioned measures achieve an imbalance of at most 50 pm, in particular at most 40 pm, in particular at most 30 pm, in particular at most 20 pm, in particular at most 10 pm, along the length of the rotating unit, in particular at every point or measuring point along the rotating unit. More preferably, the aforementioned measures can achieve an imbalance of at most 5 pm, in particular at most 2 pm.

[0054] In a further preferred embodiment of the method according to the invention, step c) is carried out in several iterations, so that the semi-finished product material is deposited in several layers. The layers can be formed from the same or different semi-finished product materials. In principle, performing step c) multiple times is advantageous because it increases the wall thickness of the produced semi-finished product and thus also influences its stability. If different semi-finished product materials are used, different properties of the semi-finished product can be achieved. For example, semi-finished product materials with different stability properties can be used to form a semi-finished product with a relatively soft and flexible outer layer and a stable and rigid inner layer.The modulus of elasticity, which can be measured using a tensile testing machine, can be used as a characteristic of the stability property. The semi-finished materials can alternatively or additionally have different degradability rates.

[0055] In general, steps c) and d) of the process, in particular the introduction and curing of the semi-finished product material, can be repeated several times to build up the semi-finished product layer by layer. It is therefore conceivable that semi-finished product material is first introduced into the rotating units using the injection units until a first layer of the

[0056] UNS-21528-P-WO- 11 - University of Stuttgart (KdöR)

[0057] The semi-finished material is deposited on the deposition surface. After a certain curing time, which preferably does not lead to complete curing of the semi-finished material, a further quantity of semi-finished material can be introduced into the rotating units via the injection units. Specifically, for example, the injection needles of the injection units can be held stationary during the extrusion of semi-finished material or guided through the rotating units in a continuous or stepwise movement. In this way, a second layer of semi-finished material is deposited on the first layer covering the deposition surface, and this second layer preferably bonds with the first layer. Therefore, it is preferred if the first layer is not completely cured, although complete curing is not excluded. This process can be repeated several times, so that a multi-layered semi-finished product can be formed.

[0058] The layered construction of the semi-finished product can contribute to improved homogeneity. Furthermore, this method can accelerate the manufacturing process, as individual thin layers of the semi-finished material cure more quickly. This can occur because solvent bound in the semi-finished material escapes, particularly evaporates, more rapidly from a comparatively thinner layer than from a comparatively thicker layer. In this way, at least two, in particular at least three, in particular at least four, and in particular at least five, or more material layers can be built up. The curing of the individual material layers can also occur or be additionally supported by other means, for example, by thermal action in the form of heating or cooling, or by chemical bonding.Therefore, the semi-finished material, particularly a polymer, can be mixed with a solvent before being introduced via the injection units; this solvent evaporates during curing. Alternatively, the semi-finished material, particularly the polymer, can be melted to make it flowable. Curing then occurs through cooling of the semi-finished material. Another possibility is to mix the semi-finished material, particularly a polymer or hydrogel, with a crosslinking agent.

[0059] UNS-21528-P-WO- 12 - University of Stuttgart (KdöR)

[0060] which promotes the formation of polymer chains, in particular a three-dimensional polymer network, and thus causes the semi-finished material to harden.

[0061] In principle, the rotational speed of the rotary units, especially the rotary molds, the feed rate of the semi-finished material, the number of material layers, the curing time of each layer, and / or the total rotation time of the rotary unit can be adjusted taking several factors into account. Furthermore, the temperature of the respective rotary unit, especially the rotary mold, can be adjusted taking several factors into account. These factors include the semi-finished material, its viscosity, the curing principle, and the dimensions of the semi-finished product after complete curing. For production purposes, it can generally be advantageous if the semi-finished material is fed into the rotary unit within 20 minutes, particularly within 10 minutes, particularly within 5 minutes, particularly within 2 minutes, and particularly within 1 minute.Furthermore, it is advantageous if the rotating unit is kept in rotation for a maximum of 90 minutes, in particular a maximum of 60 minutes, in particular a maximum of 30 minutes, and in particular a maximum of 20 minutes, until the end of step d). It is also possible that the rotating unit, in particular the rotating mold, together with the semi-finished product, is kept or conditioned in a temperature-controlled environment, for example in a heating chamber, for at least one hour, in particular a minimum of 6 hours, and in particular a minimum of 24 hours, following step d), or alternatively, the semi-finished product alone is kept or conditioned following step e). This promotes the complete curing of the semi-finished product. In the case of a hydrogel, the conditioning can alternatively take place in a refrigerator or incubator.

[0062] A radiopaque material can be added to the semi-finished product material, especially the polymer. For example, barium sulfate can be added as a radiopaque material.

[0063] UNS-21528-P-WO- 13 - University of Stuttgart (KdöR)

[0064] Furthermore, it is possible to integrate medicinal agents, such as cytostatics, into the semi-finished product material. Alternatively or additionally, it is possible to use medicinal agents with anti-inflammatory and / or antithrombotic effects (anti-inflammatory and / or antithromboinflammatory agents) and / or growth factors, peptides, such as RGD peptides, and / or other biologically active substances. In this case, it is advantageous for multilayer semi-finished products if the aforementioned medicinal agents are arranged in all material layers, or alternatively in an inner or outer layer. The aforementioned medicinal agents can also be arranged in an intermediate layer of multilayer semi-finished products, either additionally or alternatively. Different medicinal agents can be embedded in different layers of the semi-finished product material.It is also possible that cells, particularly human cells such as stem cells, endothelial cells, or smooth muscle cells, are integrated into the semi-finished product material. Different cells can be integrated or embedded in different layers of the semi-finished product.

[0065] In principle, the semi-finished product material can be selected to decompose within a predetermined period, particularly in contact with bodily fluids such as blood. Therefore, biodegradable semi-finished product materials are preferable. If the semi-finished product consists of several biodegradable layers, it can be advantageous if the individual layers degrade at different rates. For example, the individual layers can degrade radially from the inside out. Alternatively, the outermost layer can degrade gradually as the first layer, followed by other, more internal layers.

[0066] A particular advantage of the method described here is that, during the deposition of the semi-finished material on the inner deposition surface of the rotary unit, especially the negative mold, additional structures can be pre-inserted into the rotary unit or the negative mold and embedded in the semi-finished material. A preferred variant of the

[0067] UNS-21528-P-WO- 14 - University of Stuttgart (KdöR)

[0068] The invention therefore provides that a prestructure, in particular a metallic or polymer-based prestructure, is inserted into the rotating unit before or during step c). By introducing the semi-finished product material in step c), a portion, in particular only a portion, preferably a longitudinal axial section and / or a radial region, of the prestructure can then be embedded in the semi-finished product material. It is also possible for the prestructure to be completely embedded in the semi-finished product material. For example, polymer-coated stent grafts with a metallic prestructure can be produced. For this purpose, a metallic lattice structure is inserted into the rotating unit before or during step c). During the deposition of the semi-finished product material, the lattice structure is then covered with the semi-finished product material, so that the meshes or cells located in the lattice structure, i.e., the openings of the lattice structure, are covered by the deposited semi-finished product material.It is also conceivable that one or more outer layers of the future semi-finished product are first centrifugally deposited in the rotary unit, step c) is briefly interrupted to insert a metal pre-structure, and then further inner layers of the semi-finished product to be manufactured are deposited on and over the pre-structure. In this way, the pre-structure can be completely embedded in the layers of the semi-finished product material.

[0069] Generally, the prestructure can also be made of other materials. Therefore, the prestructure is not limited to a metallic prestructure, but can, for example, also be made of a plastic material. Furthermore, it is possible to use a prestructure that has a shape different from a lattice structure. For example, the prestructure can be formed by small individual elements, such as spheres or beads, discs, or rings. The prestructure, in particular the lattice structure or the individual elements, can exhibit increased radiolucency. The arrangement of the individual elements around the circumference and along the length of the semi-finished product can be chosen so that the radiolucency of the semi-finished product is increased at predetermined locations. The radiolucency can be specifically adjusted by the density of the arrangement of the individual elements.The pre-structure, especially its individual elements, can be platinum, tantalum or gold.

[0070] UNS-21528-P-WO- 15 - University of Stuttgart (KdöR)

[0071] The pre-structure may comprise or consist of a wire or multiple wires. The arrangement, number, and / or length, as well as the material and / or thickness of the wire(s), can be adjusted to determine the mechanical stability and flexibility of the semi-finished material after curing. For example, wires can be inserted and arranged within the semi-finished material to stabilize a foil formed from the semi-finished material, serving as a leaflet of a heart valve, at its edge or other points. The wire(s) may comprise or consist of a radiopaque material, such as platinum, tantalum, or gold, to enhance the radiolucency of the semi-finished material.

[0072] If only part of the prestructure is embedded in the semi-finished product material, it is particularly advantageous if the prestructure is embedded section by section in a sacrificial material when placed in the rotary unit. This sacrificial material is then removed after the semi-finished product has cured, especially after step e). The part of the prestructure embedded in the sacrificial material is then not covered by the semi-finished product material during centrifugal deposition, but remains exposed. This allows, for example, the production of implants that are intended to have a connection between the prestructure, such as a metallic lattice structure, and the semi-finished product material, such as a polymer film, only in certain areas.

[0073] It is also conceivable that a prestructure is embedded longitudinally or circumferentially in only a portion of the semi-finished material. For example, a prestructure can be provided whose length is shorter than the length of the rotational unit, particularly the negative mold. It is also possible that the prestructure extends only over a portion of the circumference of the semi-finished material. Multiple prestructures can also be provided and inserted into the rotational unit. In this way, a semi-finished product can be manufactured that is provided with a prestructure in at least one section and is free of a prestructure in at least one other section. If multiple prestructures are used for a semi-finished material, they can be different. In this case, the semi-finished material can also be provided with a prestructure along its entire length.

[0074] UNS-21528-P-WO- 16 - University of Stuttgart (KdöR)

[0075] The semi-finished material may be provided with pre-structures, which, however, can differ in their shape. Consequently, the semi-finished material may have different pre-structures in some sections and / or no pre-structure in others. The sections may be arranged consecutively in the longitudinal and / or circumferential direction of the semi-finished material.

[0076] It is particularly advantageous if the prestructure consists of a network of polymer fibers and the semi-finished product is a hydrogel. For example, the hydrogel can cure in the mold via chemical cross-linking, thereby embedding the fibers. Alternatively or additionally to chemical cross-linking, physical cross-linking, for example via a temperature change, is also possible.

[0077] The polymer fibers can be oriented in a uniform direction, for example. They can be oriented longitudinally, circumferentially, or obliquely to both the longitudinal and circumferential directions. The polymer fibers can also form a mesh or fabric. It is preferred if the fibers are oriented in two different directions, that is, at least two angles to the longitudinal direction of the semi-finished product. This allows the polymer fibers to withstand forces in different directions. This is particularly advantageous for the construction of vascular prostheses and heart valves. Such structures can be used in tissue engineering, where human cells are embedded in the hydrogel or grow on and within the hydrogel after implantation.

[0078] The polymer fibers, preferably polymer fibers oriented in different directions, can be inserted into the negative mold before step c).

[0079] In principle, it is also possible to embed several layers of polymer fibers into the semi-finished product material. For example, a first layer with polymer fibers, preferably uniformly oriented, can be placed into the negative mold.

[0080] Subsequently, a first layer of the semi-finished product material can be deposited onto these polymer fibers according to step c) of the process. After the first layer of the semi-finished product material with the embedded polymer fibers has cured according to step c) of the process, a second layer of polymer fibers, preferably

[0081] UNS-21528-P-WO- 17 - University of Stuttgart (KdöR)

[0082] The polymer fibers are placed with a uniform orientation onto the inner surface of the cured first layer of the semi-finished material. Subsequently, another layer of the semi-finished material can be deposited onto the second layer of polymer fibers according to step c) of the process and cured according to step d) of the process. The steps of inserting the polymer fibers and depositing (step c) and curing (step d) the semi-finished material can be repeated multiple times. The polymer fibers in the individual layers can have the same orientation. However, it is preferred if the polymer fibers in successive layers of polymer fibers are oriented differently, but the same way within a layer. In any case, it is advantageous if the polymer fibers are not aligned parallel to the longitudinal axis of the negative mold.

[0083] A preferred embodiment of the invention provides that, after the cured semi-finished products are removed from the rotary units, they can be further processed in a subsequent step. For example, the semi-finished products can be provided with openings in a subsequent step, particularly by laser cutting. In particular, diamond-shaped openings can be introduced into the cured semi-finished product material by laser cutting, so that the semi-finished product is essentially transformed into a lattice structure that can be used as a stent. Furthermore, it is also possible to achieve only surface structuring of the semi-finished product using a laser cutting process.

[0084] As an alternative to the aforementioned diamond-shaped openings, oval, round, or slot-shaped openings can also be created in the cured semi-finished material by laser cutting. These openings can also be used to transform the semi-finished material, for example, into a grid structure suitable for use as a stent. The cylindrical inner circumferential surface of the rotating unit does not preclude the creation of openings in the semi-finished material during the inventive process, particularly before curing according to step d) of the process. For example, the negative mold can have inwardly projecting areas that allow the formation of openings in the semi-finished material. These openings can be used, for example, for subsequent fixation, such as for UNS-21528-P-WO-18 - University of Stuttgart KdöR

[0085] Sewing with a grid structure, or providing a certain porosity that, for example, in medical implants for blood vessels manufactured from the semi-finished product, enables a nutrient supply to the tissue covered by the implant. Regardless of whether the openings are introduced into the semi-finished product during its manufacture or afterwards, for example by laser cutting, it is preferred that the openings occupy at most 30%, in particular at most 20%, in particular at most 10%, in particular at most 5%, of the total surface area of ​​the semi-finished product.

[0086] It can be provided that the semi-finished products are each combined with at least one grid structure in a subsequent step, in particular wherein the grid structure is arranged on an inner or outer circumferential surface of the semi-finished product. The produced semi-finished product can thus be used, for example, as a cover film for stents. In this process, both an inner surface and an outer circumferential surface of such a stent can be covered with a semi-finished product produced according to the inventive method. A grid structure provided with such a cover can, in particular, be used as a stent graft. It is not excluded that a grid structure is combined with two semi-finished products, wherein, for example, the inner and outer circumferential surfaces of the grid structure are each covered by one semi-finished product.

[0087] The semi-finished product, in particular the covering film, can cover the grid structure section by section, with the covered section extending at least partially circumferentially and / or at least partially longitudinally along the grid structure. The semi-finished product can extend, in particular, along the longitudinal ends of a tubular grid structure, especially a stent, over the circumference of the grid structure. Alternatively, the semi-finished product can also cover a central section of the grid structure, either completely or partially. In any case, the semi-finished product, in particular the covering film, can be arranged on an inner or outer circumferential surface of the grid structure. It is also possible for one semi-finished product to be arranged on each of the inner or outer circumferential surfaces. Generally, the grid structure can be covered section by section with several semi-finished products or covering films. UNS-21528-P-WO-19 - University of Stuttgart

[0088] It should be provided with. In all the aforementioned cases, it is preferably provided that the semi-finished product is firmly connected to the grid structure.

[0089] Another aspect of the invention relates to a valve prosthesis, in particular a heart valve prosthesis or venous valve prosthesis, which has a tubular lattice structure, particularly a metallic one. The lattice structure can have a support section and a valve section and form a longitudinal channel. The lattice structure in the support section can be covered and connected with a flexible film, which is formed, in particular, by a semi-finished product manufactured using the method described above. The film can extend into the valve section, which has two or more, in particular three, areas in which the film can be deflected radially inwards to close the longitudinal channel, at least temporarily.The semi-finished product manufactured using the previously described method can be particularly advantageous for valve prostheses, as it can exhibit a particularly thin and uniform wall thickness. Despite this thinness, it still possesses high stability, making it especially suitable as a film for artificial replacement of heart and / or venous valves. The flexible film can detach from the grid structure in the free areas and deflect radially inwards, thus opening or closing the passage through the grid structure, much like a valve.

[0090] In this context, it is preferred that the flexible film in the valve section is connected to the grid structure at several, in particular at least two or three, circumferentially spaced connection areas, especially at points or lines, so that the film forms flexibly deflectable valve leaflets between each pair of circumferentially adjacent connection areas. The design resembles a biological venous or heart valve, for example, an aortic valve. This design, adopted from the biological model, is characterized by particularly high reliability and efficiency.

[0091] UNS-21528-P-WO- 20 - University of Stuttgart (KdöR)

[0092] It is particularly preferred if the film formed by the semi-finished product consists of a hydrogel. In this case, a prestructure can consist of a cylindrical polymer network. The fiber forming the polymer network is preferably oriented such that the forces acting on the film during the closing and opening of the valve leaflets are effectively absorbed and transferred into the polymer network. This increases the implant's service life.

[0093] For example, the fiber forming the polymer network (polymer fiber) can be oriented at least predominantly in the circumferential direction. In this way, the film reinforced with the polymer fiber can withstand forces that occur when the valve prosthesis, especially the individual valve leaflets, closes.

[0094] In this context, “predominantly circumferential” means that the polymer fiber has an angle to the circumferential direction that is smaller than its angle to the longitudinal direction of the semi-finished product, where the longitudinal direction is defined by a longitudinal axis, in particular an axis of rotation, of the semi-finished product.

[0095] The flexible film can also have multiple polymer fibers that are oriented differently, i.e., have different angles to the circumferential direction.

[0096] In particular, several polymer networks can be provided, embedded layer by layer in the flexible film. Specifically, two or more polymer networks with different fiber orientations can be arranged layer by layer in the flexible film. It is possible for at least one polymer network to follow an outer edge, especially the contour, of the respective flap blade to reinforce it in a targeted manner. This can reduce the risk of tearing of the flexible film, for example, at points where the flap blade is sewn to the grid structure.

[0097] In general, the semi-finished product manufactured using the inventive method can be used to produce various medical devices for use in any hollow body of a human or animal organism. The medical devices comprising the semi-finished product can, for example, be used or implanted in blood vessels, the heart, the lungs, the esophagus, or visceral organs, as well as in urological applications.

[0098] UNS-21528-P-WO- 21 - University of Stuttgart (KdöR)

[0099] In particular, the medical devices that can be manufactured with the semi-finished product are not limited to use within blood vessels, even though such an application is mainly explained below using specific examples.

[0100] The semi-finished product produced by the inventive method can generally have a uniform wall thickness or a wall thickness that varies at least in certain areas. For this purpose, corresponding recesses can be provided in the negative mold, which cause an accumulation of material during the deposition of the semi-finished product and increase the wall thickness in these areas. This can be seen on the cured semi-finished product as protrusions on the outer surface. Areas with a greater wall thickness contribute to the stability of the semi-finished product, in particular the flexible film or hose produced with it, whereas areas with a lesser wall thickness offer greater flexibility, especially bending flexibility. The areas with greater wall thickness can extend linearly or annularly around the circumference of the semi-finished product. It is also possible for the areas with greater wall thickness to extend longitudinally or diagonally.The structures are arranged helically around the circumference of the semi-finished product. Furthermore, the areas with greater wall thickness can form raised points that, for example, improve the retention of the semi-finished product in tissue. By appropriately designing the negative mold, a roughness can also be created on the outer surface of the semi-finished product, which promotes improved fixation to the tissue or improved biological integration into the tissue.

[0101] The semi-finished product produced using the method described here is particularly suitable for the manufacture of medical implants, especially the valve prosthesis described herein. These implants are preferably designed to be implantable via a catheter. In particular, they can be configured to be radially compressed and inserted into a body cavity via a catheter. The semi-finished product can be compressed or expanded in various ways. If the semi-finished product forms a stent, it can, for example, be expanded by a balloon during implantation. UNS-21528-P-WO-22 - University of Stuttgart

[0102] The material of the semi-finished product deforms preferably plastically during this expansion. For this purpose, the semi-finished product is manufactured with a diameter that is smaller than the diameter required at the implant site.

[0103] For example, the manufacturing diameter can be between 1 mm and 2 mm. A plastically deformable material, such as polycaprolactone (PCL) or a mixture of PCL and polylactides (PLA, PLLA), is particularly suitable as a semi-finished product material in this case. It is possible that the expansion will cause the wall of the semi-finished product to stretch, thereby reducing its wall thickness.

[0104] As an alternative to plastic deformation, a semi-finished product manufactured using the method described here can be used to form a self-expanding medical device, such as a stent. In this case, the cured semi-finished product behaves elastically or quasi-elastically. For example, PLA or polyurethane can be used as the semi-finished product material. The semi-finished product is preferably manufactured with a diameter larger than the diameter of the body cavity at the implantation site. For example, the manufacturing diameter can be between 3 mm and 10 mm. The semi-finished product can also be provided with openings that are introduced during the manufacturing process and / or in a post-processing step. The openings allow the semi-finished product to be compressed to a feed diameter that is sufficiently small to allow the semi-finished product to be inserted into the implantation site.The medical device formed from the semi-finished product, such as a stent, is inserted into the body cavity via a catheter. If the semi-finished product forms a flexible film, e.g., of a stent graft or the leaflets of a valve prosthesis, the openings can be omitted. The flexible film can fold when the medical device is compressed and thus be safely guided to the implantation site via a catheter.

[0105] The features described above, including the embedding of a pre-structure, the provision of areas with different wall thicknesses, the subsequent and / or process-related creation of openings, which

[0106] UNS-21528-P-WO- 23 - University of Stuttgart (KdöR)

[0107] Downstream connections with a grid structure can be combined with each other as desired.

[0108] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying schematic drawings. These show

[0109] Fig. 1 shows a top view of a device for carrying out the method according to the invention in a preferred embodiment;

[0110] Fig. 2 shows a side view of the device according to Fig. 1;

[0111] Fig. 3 shows a top view of an alternative device for carrying out the method according to the invention in a further embodiment;

[0112] Fig. 4 shows a side view of the device according to Fig. 3;

[0113] Fig. 5 shows a top view of an alternative device for carrying out the method according to the invention in a further embodiment;

[0114] Fig. 6 shows a top view of an alternative device for carrying out the method according to the invention in a further embodiment;

[0115] Fig. 7 shows a side view of the device according to Fig. 6;

[0116] Fig. 8 shows a longitudinal sectional view through a rotation unit of a device for carrying out the method according to the invention in a preferred embodiment;

[0117] Fig. 9a shows a longitudinal sectional view of a negative mold for the production of a semi-finished product according to the inventive method in a preferred embodiment;

[0118] Fig. 9b shows a side view of a semi-finished product produced with the negative mold according to Fig. 9a;

[0119] UNS-21528-P-WO- 24 - University of Stuttgart (KdöR)

[0120] Fig. 10a shows a longitudinal section view through a negative mold for the production of a semi-finished product using the inventive method according to a further preferred embodiment;

[0121] Fig. 10b shows a side view of a semi-finished product produced with the negative mold according to Fig. 10a;

[0122] Fig. 11 shows a side view of a semi-finished product produced using the inventive method before and after a material-removing post-processing step;

[0123] Fig. 12 shows a rotary unit with an inserted pre-structure for forming an implant comprising the semi-finished product produced by the inventive method, and a side view of such a semi-finished product according to a preferred embodiment;

[0124] Fig. 13a shows the successive steps of the manufacturing process according to the invention in a preferred embodiment, wherein a pre-structure is at least partially embedded in a sacrificial material which is removed after the deposition of the semi-finished product material;

[0125] Fig. 13b shows a longitudinal sectional view of a valve prosthesis provided with the semi-finished product manufactured according to the invention in a permeable state;

[0126] Fig. 13c shows a longitudinal section through the valve prosthesis according to Fig. 13b in a closed state;

[0127] Fig. 13d shows a perspective view of the valve prosthesis in the closed state according to Fig. 13c;

[0128] Fig. 14a shows the successive manufacturing steps for a semi-finished product or an implant, wherein a pre-structure is partially kept at a distance from an internal deposition surface of the rotary unit by a sacrificial material;

[0129] UNS-21528-P-WO- 25 - University of Stuttgart (KdöR)

[0130] Fig. 14b shows a longitudinal sectional view of an implant produced by a manufacturing process according to the invention with the steps added in Fig. 14a;

[0131] Fig. 15 shows a side view of a medical implant formed from the semi-finished product produced using the manufacturing process according to the invention, with ring-shaped protrusions;

[0132] Fig. 16a shows a longitudinal sectional view of a catheter for delivering the implant according to Fig. 15;

[0133] Fig. 16b shows a longitudinal section view of the catheter according to Fig. 16a during the expansion of the implant;

[0134] Fig. 17 shows a longitudinal section view through a blood vessel with the implant inserted according to Fig. 15; and

[0135] Fig. 18 shows a cross-sectional view through a blood vessel with an implant arranged therein, which has longitudinally oriented protrusions.

[0136] Fig. 1 shows a top view of a device suitable and designed for the production of several semi-finished products 10 for medical purposes. The device comprises, in particular, several rotary units 20. Specifically, in the embodiment shown here, four rotary units 20 are provided. Each rotary unit 20 comprises a rotary mold 22, which is preferably made of a fatigue-resistant material, especially metal. A negative mold 23 is arranged on an inner circumference or on the inner surfaces of the rotary mold 22. The negative mold 23 can be inserted into the rotary mold 22. The negative mold 23 preferably comprises an elastic material, in particular silicone. An inner circumferential surface of the negative mold 23 forms the inner depositing surface 21, which is preferably cylindrical. Specifically, the depositing surface 21 can form a smooth cylindrical surface.The separation area 21 is used in the manufacturing process described here.

[0137] UNS-21528-P-WO- 26 - University of Stuttgart (KdöR)

[0138] the outer contour of the semi-finished product 10, which is produced using the method according to the invention.

[0139] In the embodiment shown in Fig. 1, the rotating units 20 are coupled to a common rotary drive 24 via a transmission means 25. The common rotary drive 24 transmits a rotary motion to all rotating units 20 by means of a transmission means 25. The transmission means 25 can be, for example, a chain or a belt.

[0140] Alternatively, gear transmissions are also possible as a transmission means 25.

[0141] The device further comprises several injection units 30. Each injection unit 30 has an injection needle 31 which can be inserted into the respective associated rotary unit 20 via an end-face opening 26. The injection needle 31 is preferably designed as a hollow needle in order to transport a semi-finished material 11 into the rotary unit 20.

[0142] In a particularly simple embodiment, as provided in the exemplary embodiments described here, the injection unit 30 comprises a cylinder 35 and a piston 34. In the exemplary embodiment shown in Fig. 1, all pistons 34 of the multiple injection units 30 are mechanically coupled to one another via a transmission means 25. The transmission means 25 can, for example, be a rod or a plate. All pistons 34 are coupled to a common conveying device 32 via the transmission means 25. The conveying device 32 can, in particular, be designed as a linear motor, which exerts a linear movement uniformly on the individual pistons 34 via the transmission means 25. In this way, the pistons 34 in the cylinders 35 can be moved simultaneously. The movement of the pistons 34 in the direction of the injection needles 31 causes the semi-finished material 11 to be expelled from the injection needle 31.

[0143] To ensure that the semi-finished material 11 is evenly distributed in the rotating units 20, the injection units 30, in particular the injection needles 31, can be moved longitudinally axially through the individual rotating units 20, in particular the negative molds 23. For this purpose, a drive unit 33 is provided, which is also designed as a linear drive. UNS-21528-P-WO-27 - University of Stuttgart

[0144] The propulsion unit 33 is preferably mechanically coupled to all injection units 30, in particular the injection needles or the cylinders 35, via a further transmission means 25. The mechanical coupling is preferably designed such that a linear movement of the propulsion unit 33 is transmitted simultaneously to all injection needles 31. In this way, the injection needles 31 can be moved synchronously longitudinally by the rotation units 20.

[0145] Figure 2 clearly shows that the transmission means 25 for the propulsion unit 33 and the conveying unit 32 are each designed as a type of rigid plate, rigidly connecting the propulsion unit 33 to the individual cylinders 35 and the conveying unit 32 to the individual pistons 34. The propulsion unit 33 moves the entire injection unit 30 longitudinally, so that the tip of the injection needle 31 is guided longitudinally through the rotating unit 20. The conveying unit 32, with its linear movement, ensures that a relative movement is established between the piston 34 and the cylinder 35, which leads to the expulsion of the semi-finished material 11 from the injection needle 31.

[0146] Fig. 3 shows a further embodiment of a device for carrying out the method according to the invention. This embodiment differs from the embodiment according to Figs. 1 and 2 in that the rotational movement of the rotary units 20 is not synchronized by a mechanical coupling, but rather by an electronic coupling, in that the rotary units 20 are signal-connected to a common control unit 60. The same applies to the injection units 30, each of which comprises independent conveying devices 32, which, however, are signal-connected to the common control unit 60 via an electronic connection. The rotary units 20 and / or the injection units 30 can be actuated synchronously via the control unit. Synchronization can be achieved by actuating the rotary units 20 and / or the injection units 30 simultaneously.However, it is also possible that the rotary units 20 and / or the injection units 30 are synchronized by means of the control unit 60 in such a way that the individual rotary units 20 and / or the UNS-21528-P-WO- 28 - University of Stuttgart KdöR.

[0147] The injection units can be 30 operated at different times or independently.

[0148] Specifically, each rotary unit 20 has its own rotary drive 24. The rotary drives 24 are coupled to a controller 60 via signal lines. The controller 60 ensures that the rotary drives 24 are actuated synchronously. This also ensures simultaneous rotation of all rotary molds 20. Likewise, each rotary unit 20 is assigned an independent injection unit 30, with each injection unit 30 comprising a separate feeder 32. The respective feeder 32 acts as a linear drive on the piston 34, which is arranged to be longitudinally displaceable within the respective cylinders 35 (Fig. 4). The feeders 32 are also connected to the controller 60 via signal lines, so that the movement of the pistons 34 in the cylinders 35 can be electronically synchronized by the controller 60.

[0149] In the side view according to Fig. 4, it can also be seen that each injection unit 30 has an independent propulsion device 33, which acts as a linear drive on the conveying device 32 and the piston-cylinder unit with the injection needle 31. Specifically, the cylinder 35 and the conveying device 32 are mounted on a common plate, which can be linearly displaced by means of the propulsion device 33. In this way, the injection needle 31 can be moved longitudinally through the rotation unit 20 by means of the propulsion device 33. The propulsion devices 33 of the injection units 30 are also coupled to the control unit 60 via signal lines, so that electronic synchronization of the propulsion movement of the individual injection needles 31 is possible.

[0150] Fig. 5 shows a further development of the device according to Fig. 3. Analogous to the device according to Fig. 3, several rotation units 20 are provided here as well, each comprising independent rotation drives 24. The rotation drives 24 are signal-connected to a controller 60 (not shown here) to ensure synchronized movement of the rotation units 20. Likewise,

[0151] UNS-21528-P-WO- 29 - University of Stuttgart (KdöR)

[0152] Each rotary mold 20 is assigned an injection unit 30, each comprising an independent conveying device 32 and an independent thrusting device 33 (Fig. 7). The conveying devices 32 and the thrusting devices 33 are also signal-connected to the control unit 60, which is not shown here.

[0153] In the embodiment shown in Fig. 5, an additional semi-finished material storage unit 14 is provided, which serves as a central storage unit 14 for all injection units 30. The central or common storage unit 14 is connected to the cylinders 35 of the individual injection units 30 via lines 15, so that semi-finished material 11 can be conveyed from the storage unit 14 into each of the cylinders 35. The linear movement of the conveying device 32 allows the semi-finished material 11 to be conveyed from the storage unit 14 into the cylinders 35 by pulling the piston 34 out of the cylinder 35.

[0154] Alternatively, it is also possible that the semi-finished material storage 14 includes a pump that continuously pumps semi-finished material 11 into the cylinders 35 or supports the feeding of the semi-finished material 11 into the cylinders 35.

[0155] Appropriate valves can ensure that semi-finished material 11 can then enter the cylinders 35. After appropriate valve actuation, the piston 34 can then be advanced into the cylinder 35 in the direction of the injection needle 31, causing the semi-finished material 11, which is located in the cylinder 35, to be guided via the injection needle 31 into the rotary unit 20. Generally, it can be provided that a common check valve is arranged between the semi-finished material storage 14, in particular between the conveying device 32, and the injection needles 31, or that individual check valves, each assigned to one injection needle (31), are arranged between the semi-finished material storage 14 and the injection needles 31. Each injection needle 31 can be assigned its own check valve and / or its own conveying device 32.The semi-finished material storage 14 is preferably formed by a closed container to prevent the evaporation of solvent.

[0156] UNS-21528-P-WO- 30 - University of Stuttgart (KdöR)

[0157] Fig. 6 shows another device in which several rotation units 20 are provided, each comprising independent rotation drives 24. Here too, the rotation drives 24 can be signal-connected to a common control unit 60.

[0158] Each rotating unit 20 is associated with an injection needle 31, which is movable longitudinally through the rotating unit 20. For this purpose, the injection needle 31 is preferably mounted on a plate or a slide that is linearly movable via the drive unit 33 (Fig. 7). In the embodiment according to Figs. 6 and 7, a central injection unit 30 is provided, which includes a common conveying unit 32. The common injection unit 30 is connected to a semi-finished material storage container 14 via a line 15. Further distributing lines 15 lead from the central injection unit 30, in particular its cylinder 35, to the individual injection needles 31. The lines 15 between the injection needles 31 and the cylinder 35 are preferably designed as flexible lines in order to be able to follow a linear movement of the drive unit 32.

[0159] Fig. 8 illustrates the manufacturing process according to the invention in a longitudinal sectional view of a rotary unit 20. The rotary unit 20 comprises a rotary mold 22 into which a negative mold 23 is inserted. The rotary mold 20, like the negative mold 23, has an end-face opening 26. An injection needle 31 can be inserted into the interior of the rotary unit 20 through the end-face opening 26. The injection needle 31 can be aligned coaxially with the rotary unit 20. Alternatively, it is possible to insert the injection needle 31 eccentrically into the rotary unit 20.

[0160] During the manufacturing process, the rotary unit, i.e., the rotary mold 22 including the negative mold 23, is set into rotation. Semi-finished material 11, for example a polymer, is introduced into the rotary unit 20 via the injection needle 31. Due to the rotation of the rotary unit 20 and the resulting centrifugal forces, the semi-finished material 11 is deposited onto an internal deposition surface 21 of the rotary unit 20.

[0161] UNS-21528-P-WO- 31 - University of Stuttgart (KdöR)

[0162] The inner depositing surface 21 essentially corresponds to the inner circumferential surface of the negative mold 23. When the semi-finished material 11 is fed into the rotating unit 20, the injection needle 31 can be moved linearly, continuously, or in, in particular, discrete steps, in order to deposit semi-finished material 11 along the entire length of the negative mold 23. The deposition of the semi-finished material 11 preferably continues until a cylindrical inner circumferential surface of the semi-finished material is formed. Any irregularities on the inner depositing surface 21 are thus completely covered, so that the semi-finished material 11, or the semi-finished product 10 produced therefrom, ultimately has a cylindrical, smooth inner circumferential surface.

[0163] Figure 8 shows a particular embodiment of the process in which the semi-finished material 11 is changed during the manufacturing process. This allows semi-finished products 10 to be formed with layers of different materials. For example, a first semi-finished material 11 can initially be fed into the rotating unit 20 via the injection needle 31 until a first layer of material is formed. Subsequently, a second semi-finished material 11, which may, for example, have different material properties, can be introduced into the rotating unit 20 via the injection needle 31 to deposit a second layer of the semi-finished material 11. The semi-finished product produced in this way then comprises two layers of different semi-finished materials 11. In particular, the layers can have different mechanical properties, for example, different moduli of elasticity. The layers can also have different degrees of degradation.In particular, an outer layer can degrade more slowly than an inner layer. This is especially advantageous when using the semi-finished product as a vascular implant. The degradation time can be investigated and measured in a physiological solution.

[0164] Furthermore, it is possible to structure the outer circumferential surface of the semi-finished product 10 to be manufactured already during the manufacturing process. Such a procedure is illustrated in Figures 9a to 10b. In the embodiment according to Figures 9a and 9b UNS-21528-P-WO-32 - University of Stuttgart KdöR

[0165] For example, the negative mold 23 has a negative structure 27. The negative structure 27 can be formed by individual recesses on the inner depositing surface 21. When the semi-finished material 11 is deposited on the depositing surface 21, a portion of the semi-finished material 11 flows into the negative structure 27. During the manufacturing process, such a quantity of semi-finished material 11 is deposited on the depositing surface 21 that the entire depositing surface 21, including the negative structure 27, is covered, resulting in a smooth, cylindrical inner circumferential surface of the semi-finished product 10. The semi-finished product 10 produced in this way has corresponding protrusions 16 on an outer circumferential surface, which are complementary to the negative structure 27. Such a semi-finished product 10 can be seen in the side view according to Fig. 9b.

[0166] In the embodiment shown in Figures 10a and 10b, the negative mold 23 has a positive structure 28. The positive structure 28 thus comprises areas of the negative mold 23 that project radially inwards into the interior of the negative mold 23. To form the semi-finished product 10, a quantity of semi-finished material 11 is deposited within the negative mold 23, so that the positive structure 28 is completely covered by semi-finished material 11. After curing, the produced semi-finished product 10 has a cylindrical, smooth inner circumferential surface. On the outer circumferential surface, however, depressions 17 appear, which are formed in a manner complementary to the positive structure 28. This design can be seen in the side view of a semi-finished product 10 produced in this way in Figure 10b.

[0167] In general, semi-finished products 10, which are essentially tube-like, can be produced using the method according to the invention. These tube-like semi-finished products 10 can have a smooth, cylindrical inner circumferential surface. The outer circumferential surface can also be smooth and cylindrical.

[0168] Alternatively, the outer circumferential surface can also be structured by means of a negative structure 27 or positive structure 28 of the negative mold 23. Generally, the negative mold 23 is preferably arranged as an insert in the rotary mold 22. The negative mold 23 can thus be replaced whenever it is worn after demolding the semi-finished product 10 or semi-finished products 10, or when it is required for

[0169] UNS-21528-P-WO- 33 - University of Stuttgart (KdöR)

[0170] The demolding of the semi-finished product 10 requires breaking or deformation. The rotary mold 22 thus remains intact during the demolding process. Alternatively, the rotary mold 22 itself can form the negative mold 23 and thus the deposit surface 21. This is particularly possible if the rotary mold 22 has a modular design or if the cured semi-finished product is deformable or flexible enough to allow demolding. The deposit surface 21 of the rotary mold 22 can be cleaned before the production of the next semi-finished product via the injection unit 30, in particular the injection needle 31, for example by introducing a solvent into the negative mold 23.

[0171] Fig. 11 shows a semi-finished product 10, which has a smooth, cylindrical outer circumferential surface. To obtain a medical implant from the semi-finished product 10, it can be additionally provided to introduce openings 13 into the semi-finished product 10 in a subsequent processing step, so that a lattice structure 41 is formed. The openings 13 can, in particular, be diamond-shaped. The introduction of the openings 13 is preferably carried out by a laser cutting process. The semi-finished product 10 is thus laser-cut to obtain the corresponding implant structures. The lattice structure 41 produced in this way can, for example, be used as a stent.

[0172] Furthermore, it is possible that the semi-finished product 10 presented here can be directly integrated into a medical device. For this purpose, for example, a pre-structure 40 can be inserted into a rotating unit 20 before the semi-finished product material 11 is deposited. Such a pre-structure 40 can, for example, be a metallic lattice structure 41. Alternatively, a pre-structure 40 made of a polymer material can also be used.

[0173] One such variant of the manufacturing process is shown in Fig. 12. A rotary unit 20 with a rotary mold 22 and a negative mold 23 is visible therein. The negative mold 23 has a smooth, cylindrical internal deposition surface 21. A pre-structure 40, for example, is embedded in the negative mold 23.

[0174] UNS-21528-P-WO- 34 - University of Stuttgart (KdöR)

[0175] A metallic lattice structure is inserted. After the pre-structure 40 is inserted, semi-finished product 11 is introduced from the injection needle 31 into the rotating unit 20. The injection needle 31 is moved linearly to ensure a uniform distribution of the semi-finished material 11 along the length of the rotating unit 20. The semi-finished material 11 is deposited on the inner deposition surface 21 and covers at least part of the pre-structure 40. The pre-structure 40 is thus embedded in the finished semi-finished product 10.

[0176] Fig. 12 also shows the result of the manufacturing process thus designed. A side view shows that the manufactured semi-finished product 10 is embedded in a lattice structure 41, or rather, the lattice structure 41 is embedded in the manufactured semi-finished product 10. The semi-finished product 10 thus forms a film 45 that covers the openings 13 in the lattice structure 41. In this way, a medical implant, for example a stent graft, i.e., a stent with a flexible covering film, can be produced directly using the manufacturing process described here.

[0177] Another possibility for manufacturing a medical implant using the semi-finished product manufacturing process described here is shown in Figures 13a-13d. In this variant, a pre-structure 40 is inserted into the rotation unit 20, in particular into the negative mold 23 arranged in the rotary die 22. The pre-structure 40 has sections with different cross-sectional diameters. The pre-structure 40 can, in particular, be designed as a lattice structure 41, which includes a support section 42 that has a smaller cross-sectional diameter than a flap section 43. The support section 42 is to be embedded in the semi-finished product 10. The flap section 43, on the other hand, is not to be embedded in the semi-finished product 10 to be manufactured. To achieve this, a sacrificial material 12 is first introduced into the negative mold 23. The sacrificial material 12 can also be introduced via the centrifugal deposition process.However, it is preferred if the sacrificial material 12 is already connected to the pre-structure 40. Thus, the sacrificial material 12 can be placed into the negative mold 23 together with the pre-structure 40. The support section 42 is positioned.

[0178] UNS-21528-P-WO- 35 - University of Stuttgart (KdöR)

[0179] the valve section 43 is embedded in the sacrificial material 12.

[0180] In a subsequent manufacturing step, the semi-finished material 11 is deposited onto the inner deposition surface 21, which is defined by the sacrificial material 12. As can be seen in Fig. 13a, this embeds the support section 42 of the pre-structure 40 into the semi-finished material 11. The flap section 43, however, remains in the sacrificial material 12 and thus does not come into contact with the semi-finished material 11. Finally, the pre-structure 40 with the cured semi-finished product 10 is removed from the rotary unit 20, and the sacrificial material 12 is removed. The result is shown in a sectional view in Fig. 13b.

[0181] Fig. 13b shows a medical device or implant in the form of a valve prosthesis 50. The valve prosthesis 50 comprises a support section 42 in which a lattice structure 41 is embedded in the semi-finished product 10. A valve section 43 adjoins the support section 42 longitudinally, in which the lattice structure 41 has a larger cross-sectional diameter than in the support section 42. In the valve section 43, the lattice structure 41 is free of the semi-finished product 10. Instead, the semi-finished product 10 extends coaxially, in a tube-like manner, from the support section 42 through the interior of the lattice structure 41 in the valve section 43. Thus, in the valve section 43, the semi-finished product 10 is free of the lattice structure 41 and forms flexibly movable valve leaflets 48. The semi-finished product 10 forms a passage channel 44 across the support section 42 and the valve section 43.

[0182] In Fig. 13b, the valve prosthesis 50 is shown in an open position. The valve leaflets 48 open the passage 44, allowing blood flow through the valve prosthesis 50, which can be used, for example, as a venous valve prosthesis or heart valve prosthesis. Fig. 13c, on the other hand, shows the valve prosthesis 50 in a closed position. In this position, the valve leaflets 48 are deflected radially inwards to close the passage 44. This closed state is shown again in Fig. 13d.

[0183] UNS-21528-P-WO- 36 - University of Stuttgart (KdöR)

[0184] shown in perspective. In this case, the valve prosthesis 50 is designed as a type of aortic valve with three valve leaflets 48. Alternatively, it is also possible that the valve prosthesis 50 comprises only two valve leaflets 48. In any case, the semi-finished product 10 forms a type of film 45, which is flexible. It is advantageous if a hydrogel is used as the semi-finished product material 11. A plastic, for example an elastomer, in particular a thermoplastic elastomer, for example a polyurethane, can also be used.

[0185] In the areas where the film 45 is connected to the grid structure 41, the film 45 remains dimensionally stable. In free areas 46, which form in the flap section 43, the flexible film 45 can, however, be deflected to close the passage 44 as a flap leaf 48. In connection areas 47, however, no radial inward deflection occurs. The connection areas 47 form areas of the film 45 that are connected to the grid structure 41 at least at points or along a line. In particular, the connection to the grid structure 41 can be made via seams. Thus, the film 45 can be connected to the grid structure 41 in some areas in the flap section 43, in particular by stitching, so that these connection areas 47 are held to the grid structure 41 at points or along a line. The areas between immediately successive connection areas 47 in the circumferential direction are referred to as free areas 46.In these free areas 46, the film 45 can deflect radially, thus forming the flap vanes 48. The pre-structure 40 can also be cylindrical in its initial state with a constant cross-sectional diameter and be expanded outwards in the area of ​​the sacrificial material 12 during the production of the flexible film 45. After removal of the sacrificial material, the pre-structure 40 can return to its initial state.

[0186] Alternatively, the flexible film 45 can be produced separately in the form of a tube made of semi-finished material 11 and subsequently attached to a grid structure 41 to form a flap. The film 45 is connected to the grid structure 41 in the areas described above, preferably by sewing. A textile section can also be provided in the support section, which is typically referred to as UNS-21528-P-WO-37 - University of Stuttgart KdöR

[0187] The "skirt" is also connected to the foil 45. The edge regions of the flap vanes 48 can also have a profile that promotes their fluid-tight closure. For example, they can be slightly curved, as is known from the prior art, for instance in pericardial flaps. Such a profile can be defined by a corresponding negative mold 23. The foil 45 preferably has a corrugated end on one side that corresponds to the curvature of the individual flap vanes 48.

[0188] A prestructure 40 can be embedded in the semi-finished product 10. The prestructure 40 can comprise a polymer network made of polymer fibers to reinforce the valve leaflets 48, particularly in areas subject to high stress, such as the edge of the valve leaflets 48. Furthermore, the skirt can be embedded in the semi-finished product 10. The polymer network and the skirt can be provided in different areas or sections of the semi-finished product 10. For example, in the production of the flexible film 45, a skirt can be embedded in the support section 42 and a polymer network in the valve section 43 of the semi-finished product 10 or the valve prosthesis, respectively. The skirt can serve to connect the semi-finished product 10 with a lattice structure. The semi-finished product 10 is preferably made of a hydrogel.

[0189] It is also generally possible that the semi-finished product 10 produced by the method described here, in particular the tube produced by the method described here, independently forms a "skirt". The semi-finished product can, in particular, consist of a hydrogel. The "skirt" is preferably connected to an outer surface of the lattice structure 41, in particular by suturing. In the implanted state, the "skirt" seals the lattice structure 41 against the surrounding tissue.

[0190] In general, it is conceivable that the flap wing 48 could have thickenings or bulges in certain places by means of targeted cutouts in the negative mold 23.

[0191] The outer circumferential surface has raised areas that project radially outwards. For example, the recesses in the negative mold 23 can be designed such that the wall thickness of the flexible film 45 in the flap wing 48 is thickened at the edges. This reinforces the edges of the flap wings 48, making them more resistant to damage.

[0192] UNS-21528-P-WO- 38 - University of Stuttgart (KdöR)

[0193] The flaps must be able to close properly and absorb the forces occurring during closing. Areas connected to the grid structure 41, for example by stitching, can also have a greater wall thickness. Conversely, other areas of the flap blades 48, which have a comparatively smaller wall thickness, offer increased flexibility, particularly bending flexibility. The change in wall thickness, for example from a central area, often referred to as the "belly," of a flap blade 48 to its edge and / or to the connection points with the grid structure 41, can be gradual in order to avoid localized stress concentrations.

[0194] Figures 14a and 14b show another variant in which a prestructure 40 can be embedded section by section into a semi-finished product 10. In this variant, the rotary unit 20 has a rotary mold 22 in which a negative mold 23 is inserted, the negative mold 23 forming the inner deposit surface 21, which is smooth and cylindrical. A prestructure 40, for example in the form of a lattice structure 41, is placed into the negative mold 23. The prestructure 40 is deflected radially inwards, for example in a central section 49, so that the prestructure 40 has a distance from the deposit surface 21 in the central section 49. This deflection can be achieved, for example, by pre-forming the prestructure 40 into this tapered shape by means of a heat treatment or by inserting clamping elements within the prestructure 40 that pull the prestructure 40 radially inwards in the central section 49.

[0195] In a further manufacturing step, the semi-finished material 11 is introduced into the rotating unit 20 and centrifugally deposited. During this process, the pre-structure 40 is embedded in the semi-finished material 11 at the edges. In the central section 49, however, the pre-structure 40 remains free of the semi-finished material 11. After the semi-finished material 11 has hardened, the pre-structure 40 is removed from the rotating unit 20 along with the semi-finished product 10. The inwardly tapered central section 49 can then be detached, allowing the pre-structure 40, or lattice structure 41, to enter a stress-free resting state, in which the lattice structure 41 assumes a substantially hollow cylindrical shape. This is shown in Fig. 14b. In its hardened state, the semi-finished product 10 forms a UNS-21528-P-WO- 39 - University of Stuttgart KdöR

[0196] The foil 45 is firmly attached to the grid structure 41 at its edges and rests loosely on the outer circumference of the grid structure 41 in the central section 49. In a subsequent processing step, the foil 45 can also be selectively attached to the grid structure 41 at certain points, for example by sewing. However, this is not strictly necessary.

[0197] In all embodiments, the rotating units 20 preferably have one or more holes on the opposing end walls, particularly in an end wall opposite the end face opening 26, to ensure air circulation through the rotating units 20. The holes are preferably arranged eccentrically to the axis of rotation of the rotating units 20. The semi-finished products 10 produced by the method described here generally have a cylindrical, and in particular smooth, inner circumferential surface. However, the outer circumferential surface can be structured. The structuring can be introduced during the manufacturing process, as shown, for example, in the embodiments according to Figures 9a, 9b and 10a, 10b. Alternatively, it is possible to carry out the structuring in a subsequent processing step, for example, by a hot stamping or cold stamping process.This can also be done on the inner surface of the semi-finished product 10. It is also possible to carry out the structuring using a laser in a subsequent processing step.

[0198] Furthermore, openings 13 can be introduced into the semi-finished product 10 by means of laser post-processing. These openings 13 can be diamond-shaped, round, oval, or even slits or circles. It is also possible to provide the manufactured semi-finished product 10, which is tubular in shape, with a continuous longitudinal cut, so that the semi-finished product 10 has a C-shaped cross-section and can be opened completely along its length. Regarding the pre-structure 40, it can be provided that it is made of a stronger material, for example, metal. The pre-structure 40 can be formed by laser cutting from a metallic tubular blank. It is also possible that the pre-structure 40 is designed as a mesh, whereby the mesh can be formed from wires or threads connected to each other. UNS-21528-P-WO- 40 - University of Stuttgart KdöR

[0199] The wires are interwoven, woven, or knitted. They can also be meandering or otherwise bent so that they do not cross and therefore do not form a mesh.

[0200] The prestructure 40 can also be a mesh produced by electrospinning. Electrospinning processes in which the fibers can be precisely oriented are particularly advantageous. Such electrospinning processes can produce meshes that transmit forces in specific directions. In particular, these meshes can exhibit anisotropic, i.e., direction-dependent, properties.

[0201] Furthermore, it is not excluded that the pre-structure 40 is also designed as a semi-finished product 10, which was produced using the method described herein. For example, a semi-finished product 10 can be produced using the method described herein and, in a post-processing step, provided with openings by laser cutting to form a lattice structure 41. This lattice structure 41 can then be used as the pre-structure 40. The pre-structure 40 can generally be made of a metal, in particular biocompatible metal alloys. The use of nitinol or stainless steel as the material for the pre-structure 40 is particularly preferred. Alternatively, polymers can also be used as the material for the pre-structure 40. The pre-structure 40 can also include radiopaque components. It is also possible to insert one or more pre-structures 40 into the rotating units 20.A stabilizing prestructure 40 can be used, which, for example, is designed as a lattice structure 41. Additionally, radiopaque marking elements can be inserted into the negative mold 23, so that these radiopaque marking elements are also embedded in the semi-finished product 10. Electrical components, such as electrodes or sensors, can also be used as prestructures 40. In this case, the prestructure 40 does not have a load-bearing function.

[0202] Synthetic or biological polymers are preferably used as semi-finished material 11. In particular, polycaprolactones (PCL) and polylactides can be used.

[0203] UNS-21528-P-WO- 41 - University of Stuttgart (KdöR)

[0204] (PLA, PLLA), polyurethanes, or a combination thereof can be used. Biological or synthetic polymers, or a combination thereof, can also be used. In the context of this application, proteins are considered biological polymers. Furthermore, hydrogels can be used as semi-finished material 11. Suitable hydrogels include, for example, polyvinyl alcohol (PVA), gelatin, fibrin, collagen, or combinations thereof. It is also possible to use a combination of hydrogels and polymers as semi-finished material 11. In particular, hydrogels and polymers can be deposited layer by layer to form a multilayer semi-finished product 10, which has layers of polymers and / or layers of hydrogels.

[0205] Hydrogels are preferably cured using crosslinking agents. Alternatively, they can also be cured by changing the temperature, in particular by reducing the temperature of the rotating units during the hydrogel reaction in the rotating units 20. Polymers can also be cured by the evaporation of a solvent contained in the semi-finished material 11. This can be promoted, for example, by increasing the temperature of the rotating units 20. In general, the rotating units 20 can therefore be temperature-controlled. The rotating units 20 can have corresponding temperature control devices. These devices can increase or decrease the temperature within the rotating units 20. In particular, the temperature control devices can ensure that the temperature within the rotating units 20 is kept constant.

[0206] The rotary units, the semi-finished material storage unit(s) and the injection units, in particular all units or assemblies of the manufacturing devices shown in Figs. 1 to 7, can be located in a chamber in which the temperature and humidity are controlled.

[0207] The hardening of the material in step d) can be achieved by solvent evaporation. It is advantageous to apply the material in several layers to allow for evaporation between layers. It is also advantageous to remove the solvent in a controlled manner via air supply or extraction.

[0208] UNS-21528-P-WO- 42 - University of Stuttgart (KdöR)

[0209] Curing can also occur through temperature control or temperature changes during the process. For example, hydrogels can be physically cross-linked through cooling. Chemical cross-linking can also lead to curing.

[0210] Figures 15-18 each show an implant 55 formed by a semi-finished product 10 manufactured according to the invention. In the illustrated embodiment, the implant 55 has several protrusions 16 that extend as ring-shaped protrusions 16 around the circumference of the implant's outer surface. The protrusions 16 are an integral part of the implant 55, which is formed entirely and, in particular, exclusively by the semi-finished product 10. A negative mold 23 is used in the manufacture of the semi-finished product 10, which has corresponding ring-shaped recesses in which the semi-finished product material 11 can be deposited. This creates the ring-shaped protrusions 16 on the semi-finished product 10 and subsequently the implant 55. The ring-shaped protrusions 16 can be arranged at regular intervals along the length of the implant 55. The implant 55 is preferably plastically deformable.Figure 15 shows the manufactured state of the implant 55, i.e., a state in which no external forces act on the implant 55. In the manufactured state, the implant 55 has a first wall thickness.

[0211] The implant 55 is preferably intended for use in a blood vessel 80. A catheter 70 is preferably used to introduce the implant 55 into the blood vessel 80. Such a catheter 70 is shown in Figures 16a and 16b. The catheter 70 is preferably a balloon catheter. The catheter 70 comprises a proximal catheter end 71, which may have connections for fluid supply and / or manipulation devices for actuating the catheter 70 by an operator. Furthermore, the catheter 70 has a distal catheter end 72, which has an exit opening of a guide channel 74. A guide wire 73 can be passed through the guide channel 74 to facilitate the insertion of the catheter 70 into a blood vessel 80. A balloon 75 is arranged on the catheter 70 in the region of the distal catheter end 72. The balloon 75 is connected to the proximal catheter end 71 by means of an inflation channel.

[0212] UNS-21528-P-WO- 43 - University of Stuttgart (KdöR)

[0213] Connection, particularly in fluid connection, so that the balloon 75 can be transferred from a compressed state to an expanded state by supplying fluid. In the illustration according to Fig. 16a, the balloon 75 is in a compressed state and carries the implant 55 with its outwardly projecting, ring-shaped protrusions 16. In this state, the catheter 70 can be inserted into a blood vessel 80 until the implantation site is reached.

[0214] Fig. 16b shows the catheter 70 in a state it typically assumes at the implantation site. Once the implantation site is reached, a fluid, preferably a saline solution, is pumped into the balloon 75 via the inflation channel, thereby building up pressure that causes the balloon 75 to expand. The balloon 75 thus expands, and the implant 55 attached to it follows this radial expansion. The plastically deformable implant 55 is thereby stretched, reducing its wall thickness. The implant 55 thus assumes its implantation state. In the implantation state, the implant 55 has a second wall thickness that is thinner than the first wall thickness in its manufactured state.

[0215] The implantation status of the implant 55 is shown in detail in Fig. 17. Fig. 17 shows a blood vessel 80 with the implant 55 inserted therein. The implant 55 was introduced into the blood vessel 80 using the catheter 70, which has since been removed. The catheter 70 is removed by withdrawing the fluid from the balloon 75, causing the balloon 75 to collapse. This detaches the balloon 75 from the inner surface of the implant 55. The balloon 75, and thus also the catheter 70, are then free and can be withdrawn from the blood vessel 80.

[0216] Figure 17 clearly shows that the protrusions 16 of the implant 55 offer a particular advantage. The protrusions 16 can press into the tissue of the blood vessel 80, especially into the vessel wall, thus resulting in improved anchoring of the implant 55 in the blood vessel 80.

[0217] In the cross-sectional view according to Fig. 18, this is further illustrated using an implant 55 with elevations 16, which are longitudinally extending elevations UNS-21528-P-WO- 44 - University of Stuttgart KdöR

[0218] 16 or ribs are formed. The elevations 16 or ribs consequently run parallel to a longitudinal axis of the implant 55. It can be seen that the implant 55 nestles against the vessel wall of the blood vessel 80, with the elevations 16 penetrating the vessel wall of the blood vessel 80 and thus anchoring the implant 55 in the blood vessel 80.

[0219] In addition to or as an alternative to improved anchoring of the implant 55, the longitudinally extending projections 16 in the embodiment shown in Fig. 18 can cause controlled disruption of an atherosclerotic plaque during the widening of a stenosis. The projections 16 can also be wound helically around the longitudinal axis of the implant 55 and / or accommodate a lattice structure and / or other pre-structures.

[0220] The protrusions 16 shown in the figures, particularly in Figures 17 and 18, are schematically exaggerated for clarity and may be significantly flatter in reality. Where the implant 55 is shown in the figures in an expanded state, particularly in the implanted state, this representation is highly idealized insofar as the blood vessel 80 is depicted as having a straight course. In practice, however, blood vessels 80 are often curved and / or have varying diameters, so that the implant 55 also expands in such a section of the blood vessel 80 that has a curved course and / or a varying diameter. The implant 55 adapts to the shape of the blood vessel 80. For this purpose, the implant 55 has a corresponding bending flexibility. The protrusions 16 in the embodiment according to Figure 16 are shown in the figures in a simplified form.17 in the form of circumferential rings offer improved bending flexibility because flexible areas (between the rings) and stabilizing areas (on the rings) are arranged alternately in the longitudinal direction.

[0221] In general, the transition between the surveys 16 and thinner areas between the surveys 16 can be continuous, especially gradual.

[0222] UNS-21528-P-WO- 45 - University of Stuttgart (KdöR)

[0223] In all embodiments, the implant can have 55 openings 13. If the implant 55 has protrusions 16, the openings 13 are preferably located in the areas between the protrusions 16. However, it is conceivable to provide openings 13 in the area of ​​the protrusions 16 instead of between them or in addition to them.

[0224] UNS-21528-P-WO- 46 - University of Stuttgart (KdöR)

[0225] Reference symbol list

[0226] 10 semi-finished products

[0227] 11 Semi-finished product material

[0228] 12 Victim material

[0229] 13 Opening

[0230] 14 Semi-finished product storage 15 Line

[0231] 16 Survey

[0232] 17 Further Study

[0233] 20 rotation units

[0234] 21 Separation area

[0235] 22 Rotary mold

[0236] 23 Negative form

[0237] 24 Rotary drive

[0238] 25 means of transmission

[0239] 26 Front surface opening

[0240] 27 Negative structure

[0241] 28 Positive structure

[0242] 30 injection units

[0243] 31 injection needles

[0244] 32 Funding facility

[0245] 33 Tunneling device

[0246] 34 pistons

[0247] 35 cylinders

[0248] 40 Prestructure

[0249] 41 Grid structure

[0250] 42 Support section

[0251] 43 Valve section

[0252] 44 through channel

[0253] 45 slides

[0254] 46 free space

[0255] UNS-21528-P-WO- 47 - University of Stuttgart (KdöR)

[0256] 47 Connection area 48 Flap wing

[0257] 49 tapered midsection 50 valve prosthesis

[0258] 55 implant

[0259] 60 Control

[0260] 70 catheters

[0261] 71 proximal catheter end 72 distal catheter end 73 guide wire

[0262] 74 Guide channel

[0263] 75 Balloon

[0264] 80 blood vessels

[0265] UNS-21528-P-WO

Claims

1. - 48 - University of Stuttgart KdöR Claims 1. A method for producing semi-finished products (10) for medical purposes, the method comprising the following steps: a) Providing several rotating units (20) each with a cylindrical, internal separation surface (21), b) Rotating the rotation units (20) about each of the rotational axes assigned to the respective rotation unit (20), c) Introducing a semi-finished material (11) via injection units (30) into the rotating units (20) so that the semi-finished material (11) is deposited on the inner depositing surfaces (21) of the respective rotating units (20) under the influence of a centrifugal force, in particular over the entire surface, d) Curing of the semi-finished material (11) under rotation of the respective rotation units (20) to form the semi-finished product (10), and e) Removal of the semi-finished products (10) from the rotary units (20), wherein in step c) a feed quantity of the semi-finished product material (11) is adjusted such that the tubular semi-finished products hardened by step d) each form a continuously cylindrical, in particular smooth, inner circumferential surface.

2. Method according to claim 1 characterized by the fact that the rotational units (20) each have a dimensionally stable rotational mold (22) and a, preferably elastic, negative mold (24) which is arranged inside the rotational mold (22) and forms the cylindrical, internal deposition surface (21).

3. Method according to claim 1 or 2 characterized by the fact that UNS-21528-P-WO- 49 - University of Stuttgart (KdöR) the injection units (30) each have injection needles (31) which are each inserted into the respective rotation unit (20) via an end face.

4. Method according to any one of the preceding claims characterized by the fact that the rotation units (20) and the injection units (30) interact in such a way that steps c) to d) are carried out simultaneously in all rotation units (20).

5. Method according to claim 3 or 4 characterized by the fact that in step c) the semi-finished material (11) is driven out of the injection needle (31) by a conveying device (32) and / or the injection needle (31) is moved longitudinally axially through the rotation unit (20) by a propulsion device (33).

6. Method according to any one of the preceding claims characterized by the fact that in step c) the semi-finished material (11) is introduced into the rotary units (20) from a common semi-finished material storage (14), in particular by means of one or more conveying devices (32).

7. Method according to any of the preceding claims characterized by the fact that at least some of the, in particular all, rotation units (20) are moved by a common rotation drive (24) and / or at least some of the, in particular all, injection needles (31) are moved by a common propulsion device (33) and / or that the semi-finished product material (11) is conveyed through the injection needles (31) by means of a common conveying device (32).

8. Method according to any one of claims 1 to 6 characterized by the fact that the rotation units (20) each by individual rotation drives (24) UNS-21528-P-WO- 50 - University of Stuttgart (KdöR) and / or that the injection units (30) are each moved by individual propulsion devices (33) and / or that the semi-finished material (11) is conveyed by individual conveying devices (32) each assigned to an injection needle (31), wherein the rotary drives (24) and / or propulsion devices (33) and / or conveying devices (32) are synchronously operated by a common control (60).

9. Method according to any of the preceding claims characterized by the fact that Step c) is carried out in several iterations, so that the semi-finished material (11) is deposited in several layers.

10. Method according to claim 9 characterized by the fact that the layers are formed from different semi-finished materials (11).

11. Method according to any of the preceding claims characterized by the fact that before or during step c) a pre-structure (40), in particular a metallic one, is inserted into the rotating unit (20).

12. Method according to claim 11 characterized by the fact that by introducing the semi-finished material (11) in step c) a part, in particular only a part, preferably a longitudinal axial section and / or a radial area, of the pre-structure (40) or the pre-structure (40) is completely embedded in the semi-finished material (11).

13. Method according to claim 12 characterized by the fact that the pre-structure (40) is embedded section by section into a sacrificial material (12), which is removed after step e). UNS-21528-P-WO- 51 - University of Stuttgart (KdöR) 14. Method according to any of the preceding claims characterized by the fact that the semi-finished products (10) are provided with openings (13) in a subsequent step, in particular by laser cutting.

15. Method according to any of the preceding claims characterized by the fact that the semi-finished products (10) are each connected with at least one grid structure (41) in a subsequent step, in particular wherein the grid structure (41) is arranged on an inner surface or an outer surface of the semi-finished product (10).

16. Valve prosthesis (50), in particular heart valve prosthesis or venous valve prosthesis, with a, in particular metallic, tubular grid structure (41) which has a support section (42) and a valve section (43) and forms a longitudinal axial passage channel (44), wherein the grid structure (41) in the support section (42) is covered and connected with a flexible film (45) which is formed in particular by a semi-finished product (11) produced by the method according to one of the preceding claims, wherein the film (45) extends into the valve section (43) which has free areas (46) in which the film (45) can be deflected radially inwards in order to close the longitudinal axial passage channel (44) at least temporarily.

17. Valve prosthesis (50) according to claim 16 characterized by the fact that The flexible film (45) in the flap section (43) is connected to the grid structure (41) at several, in particular at least two or three, connection areas (47) spaced apart from each other in the circumferential direction of the grid structure (41), in particular point-like or linear, so that the film (45) forms flexibly deflectable flap wings (48) between each pair of connection areas (47) that are immediately adjacent in the circumferential direction. UNS-21528-P-WO

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