Three-dimensional textile cell culture scaffold

Abstract

The invention relates to a textile cell culture scaffold comprising a plurality of monofilament yarns or multifilament yarns that form a three-dimensional structure, wherein the three-dimensional structure is formed by a braid, and wherein the cell culture scaffold comprises multiple layers and / or comprises plied monofilament yarns or multifilament yarns.

Description

[0001] RWTH Aachen University, Düsseldorf, December 22, 2025 Our reference: RD 42849 / AL

[0002] RWTH Aachen University, a public corporation

[0003] Templergraben 55, 52062 Aachen, Germany

[0004] Textile three-dimensional cell culture scaffold

[0005] Description

[0006] Mammalian cells grow in vivo in a complex three-dimensional environment that is difficult to replicate in the laboratory. Cell cultures are typically performed on two-dimensional surfaces such as glass or plastic. In recent years, advanced cell culture methods have been developed to cultivate cells in vitro in three-dimensional environments, creating more realistic cell environments for biomedical research. One established approach, for example, is to grow cells on scaffolds. Nanofibres, foams, or membranes are also used.

[0007] Various scaffold structures for cell cultures are known. For example, US 11629321 B2 describes a scaffold for cell culture or tissue engineering that contains a fiber fleece with a three-dimensional network structure made of biodegradable scaffold fiber. The fibers can be produced by a spinning process from polycaprolactone, polydioxanone, poly(L-lactide), poly(DL-lactide-co-glycolide), polyethylene oxide, polylactic acid, or polyvinyl alcohol. A mean diameter of 100 nm to 3 pm is described for the scaffold fibers. EP 3836978 A1 describes a tissue scaffold made of a synthetic polymer and one or more natural polymers selected from elastin, fibrin, and collagen. The synthetic polymer may include polycaprolactone. The tissue scaffold can form a single-layer structure, but not multi-layered structures.US 2013 / 0183352 A1 describes a nanofiber scaffold that can be seeded with cells and has a basket-weave-like configuration mimicking the structure of biological tissue, such as heart tissue, as well as methods for its fabrication. The nanofiber scaffold can be made of polycaprolactone. The scaffold is fabricated using a noobing process and does not include interwoven or entangled fibers. US 8071007 B1 describes the use of fused deposition modeling (FDM) to fabricate three-dimensional (3D) bioresorbable scaffolds from lattice-like layers of polycaprolactone or polymer-ceramic composites such as polycaprolactone / hydroxyapatite or polycaprolactone / tricalcium phosphate.

[0008] Further scaffold structures are disclosed in the following documents. WO 2012 / 007078 A2 describes a cell culture comprising a three-dimensional, woven or knitted fiber scaffold. The fibers contain a cell-loaded fiber in which living cells are embedded. EP 3884033 A1 describes a textile construction comprising a woven or knitted textile with an average pore size, forming a textile cell growth matrix. The fibers may, for example, include polycaprolactone. EP 3946147 A1 describes a biodegradable, three-dimensional scaffold for use in tissue engineering, producible by additive manufacturing such as 3D printing. The scaffold material may include s-caprolactone or a copolymer of s-caprolactone and p-dioxanone.

[0009] Polycaprolactone scaffold structures are known in the context of ligament and tendon tissue engineering. Bauer et al., Polymers 2024, 16, 488, describe three-dimensional, macroporous, two- and four-layer braided scaffold structures with dimensions comparable to a human anterior cruciate ligament. The fibers from which the scaffold structures are braided are monofilaments with a round cross-section or multifilaments consisting of ten individual filaments per yarn with a snowflake-shaped cross-section, each made from melt-spun polycaprolactone. The fibers may have a chitosan surface modification. Bauer et al., Fibers 2022, 10, 23, describe further melt-spun polycaprolactone fibers for applications in ligament and tendon tissue engineering. Three-layer braided structures made of 96 filaments, produced using multi-layer round braiding, are described, as well as braided structures made of 192, 288 or 384 filaments, which have high tensile strength and tensile force (or tensile strength).primary stability) and exhibited the stiffness of a human anterior cruciate ligament.

[0010] Emonts et al., Polymers 2024, 16, 2349, describe investigations into the mechanical and biological properties and in vitro degradation of braided structures made from melt-spun polycaprolactone fibers for applications in ligament and tendon tissue engineering. Single-layer and nine-layer braids consisting of 48 and 432 filaments, respectively, of various polycaprolactone materials are described. Fibers made from a copolymer of polycaprolactone with 5% polyhydroxyacetic acid (polyglycolic acid, PGA) are also described. However, the described braided structures are strand-like scaffolds, modeled on the dimensions of a human anterior cruciate ligament, and are not designed for cell culture applications.

[0011] Polycaprolactone (PCL) is an aliphatic polymer that is biocompatible, biodegradable, and possesses mechanical and viscoelastic properties that allow its use in conjunction with human tissue. Polycaprolactone is approved by the Food and Drug Administration (FDA) as an implantable material, for example, as suture material. For cell culture applications, 3D Insert™ PCL scaffolds from 3D Biotek, manufactured using precision microfabrication technology, are commercially available. Products available on the market are predominantly additively manufactured, electrospun, or hydrogel-based. Such approaches are primarily designed to achieve the desired 3D architecture and cell-material interaction. However, for many tissues, such as ligament and tendon cultures, other aspects, such as the mechanical properties of the body tissue, are also relevant.These properties cannot be replicated with currently available products, meaning that research findings from 3D cell culture cannot be directly transferred to in vivo applications and have limited applicability. As soon as mechanical aspects need to be considered during the development of a market-ready medical device, it becomes necessary to change the substrate. Therefore, there is a need for specially adapted structures, particularly for the cell culture of ligament and tendon cells.

[0012] It is therefore an object of the present invention to provide a method by which at least one disadvantage of the prior art is at least partially overcome. In particular, it is an object of the present invention to provide a scaffold for three-dimensional cell cultures that can improve the transferability of the results obtained therewith to in vivo applications.

[0013] The problem is solved according to the invention by a textile cell culture scaffold having the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims and in the description, wherein further features described or shown in the dependent claims or in the description can individually or in any combination constitute an object of the invention unless the context clearly indicates otherwise.

[0014] The present invention relates to a textile cell culture framework comprising a plurality of monofilament yarns or multifilament yarns forming a three-dimensional structure, wherein the three-dimensional structure is formed from a braid, and wherein the cell culture framework comprises several layers and / or plied monofilament yarns or multifilament yarns.

[0015] A key advantage of yarn-based scaffolds is that they are pre-fabricated for cell culture dishes such as well plates and are better suited to clinical applications in terms of morphology, mechanical properties, and degradation kinetics. This allows for the generation of results in in-vitro cell culture studies, particularly for ligament and tendon cells, that demonstrate improved transferability to subsequent research steps such as dynamic cell culture and in-vivo studies, including preclinical and clinical trials.

[0016] The term "textile" refers to structures made from interconnected fibers of various raw materials, particularly natural or synthetic fibers. Textile structures include yarns as well as two-dimensional and three-dimensional textile materials such as woven, knitted, and braided fabrics. Accordingly, the adjective "textile" describes products made from interconnected, spun filaments or yarns, especially woven, knitted, or braided products.

[0017] According to DIN 60900, the term "yarn" refers to linear textile structures. Yarn is a long, thin structure made of one or more filaments (fibers). A yarn can be a multifilament yarn, composed of several individual filaments, or a monofilament yarn, composed of a single filament. The term "filament yarn" therefore encompasses both monofilament and multifilament yarns. Regardless of whether the yarn is a monofilament or multifilament yarn, it can also be plied, with several filaments lying side by side.

[0018] The term "plied" yarn refers to yarns that are made up of at least two or more yarns which are joined together in parallel.

[0019] The term "filament" refers to thin, thread-like, continuous or discrete elongated structures that serve as the starting material for games and braids. A "multifilament" comprises several individual filaments. Within the scope of the present invention, the terms "fiber" and "filament" are used synonymously, as in the context of man-made fibers in this publication. According to DIN 60000 (1969), the term "braid" refers to sheet and solid structures with a regular thread density and a closed fabric appearance, whose braiding (lace) threads intersect obliquely towards the fabric edges.

[0020] In embodiments where the cell culture scaffold is formed from mono- or multifilament yarns that are not plied, the scaffold can comprise 2 to 20 layers. In embodiments where the cell culture scaffold is formed from plied monofilament yarns, the scaffold can be single-layered or comprise 2 to 20 layers. Preferably, a cell culture scaffold formed from plied monofilament yarns is a single-layered cell culture scaffold.

[0021] The plied yarns according to the invention are preferably made of monofilament yarns.

[0022] In preferred embodiments, the cell culture scaffold is formed from plied filament meshes. Plying allows the "thread count"—a fixed term referring to the number of yarns processed in the mesh—to be increased without adding further layers. The parallel arrangement of the yarns within the plied mesh results in a flatter textile structure than a multi-layered mesh. This is advantageous for a cell culture scaffold. In certain embodiments, the plied monofilament meshes have a ply count in the range of > 2 to < 100, preferably in the range of > 2 to < 20. Good cell culture results are achievable within these ranges.

[0023] In embodiments, the cell culture scaffold comprises a thread count in the range of > 3 to < 3000, preferably in the range of > 20 to < 1000, and preferably in the range of > 200 to < 800, of mono- and / or multifilament yarns. Within these ranges, cell culture scaffolds with good mechanical properties could be provided, enabling in vitro cell culture of ligament and tendon cells. In a braid, the monofilament or multifilament yarns are arranged in the production direction of the braid at an angle α to each other and at an angle α / 2 to the longitudinal axis (tension direction) in the production direction of the braid, where the angle α is: 0 < α < 90°. In embodiments, the monofilament or multifilament yarns are arranged in the production direction of the braid at an angle α in the range of > 4° to < 60°, preferably in the range of > 8° to < 30°.For use in the context of ligaments and tendons, such an arrangement is advantageous because it can approximate the characteristic force-strain behavior of native ligaments and tendons with superimposed structural and material strain. Simultaneously, the yarns are positioned at an angle of α / 2 to the longitudinal axis, i.e., to the direction of tension. At a small angle, this creates a growth-guiding structure for the cells, roughly in the longitudinal direction.

[0024] In embodiments, the cell culture scaffold has a circular shape in the plane of the production direction of the braid. Preferably, the cell culture scaffold has a circular shape in the plane of the production direction of the braid, with dimensions suitable for use in conventional multiwell plates, for example, 6, 12, 24, 48, or 96-well plates. Such a shape can be produced, for example, using a laser or mechanical cutting devices. For use in cell culture, for example, in well plates, the cell culture scaffolds are then already available pre-assembled as laboratory consumables. In embodiments, the filaments are only connected to each other at the edge of the circular surface, for example, by fusing or gluing. In particular, laser cutting to a circular shape can be combined with fusing or gluing. Preferably, the fibers are not connected to each other except at the edge.This has the advantage that, apart from the edge areas, the mesh allows cells to colonize the exposed filaments. In embodiments, the cell culture scaffold has a height of > 1 mm to < 12 mm in the direction perpendicular to the production direction of the mesh for a multilayer arrangement. In embodiments, a cell culture scaffold formed from plied filament yarns has a height of > 100 pm to < 4 mm.

[0025] In embodiments, a single-layer cell culture scaffold formed from plied monofilament yarns can have a ply ratio of > 2 to < 100, preferably > 2 to < 20, and / or a thread count of > 20 to < 1000, preferably > 200 to < 800, and / or a height of > 100 µm to < 4 mm. Furthermore, the monofilament yarns can be arranged in the production direction of the braid at an angle α of > 4° to < 60°, preferably > 8° to < 30°, to each other.

[0026] In various embodiments, the cell culture scaffold has the following properties:

[0027] - a porosity in the range of > 40% to < 90%, preferably in the range of > 60% to < 90%, preferably in the range of > 75% to < 90%, and / or

[0028] - a mean pore size in the range of > 10 pm to < 500 pm, preferably in the range of > 50 pm to < 300 pm, preferably in the range of > 100 pm to < 250 pm.

[0029] In this case, at least 50%, preferably at least 65%, preferably at least 80% of the pores between the filament yarns have a pore size in the range of > 10 pm to < 500 pm, preferably in the range of > 50 pm to < 300 pm, preferably in the range of > 100 pm to < 250 pm.

[0030] The porosity is determined primarily optically with or without micro-computed tomography or by capillary flow porometry. The mean pore size is determined primarily optically with or without micro-computed tomography or by capillary flow porometry.

[0031] In embodiments, the cell culture scaffold has the following mechanical properties: - a direction-dependent tensile strength, wherein the tensile strength in the transverse direction to the production direction of the mesh is at least 80% lower than the tensile strength in the production direction of the mesh, and / or

[0032] - an elongation at break in the range of > 10% to < 150%, preferably in the range of > 10% to < 80%, preferably in the range of > 10% to < 50%, and / or

[0033] - a maximum tensile force in the production direction of the braid of at least 150 N per mm of the braid in the transverse direction, preferably of at least 225 N per mm, preferably of at least 300 N per mm, for a multi-layered arrangement of the braid, or

[0034] - a maximum tensile force in the production direction of the braid of at least 20 N per mm of the braid in the transverse direction, preferably of at least 50 N per mm, preferably of at least 75 N per mm, for a cell culture scaffold formed from plied filament yarns.

[0035] The direction-dependent tensile strength describes the difference in tensile strength between the production direction (preferred direction) and the transverse direction. The direction-dependent tensile strength is determined, in particular, in a uniaxial quasi-static tensile test based on the French standard NF S 94-167-2, whereby the test length and test speed differ, being 40 mm and 40 mm / min, respectively.

[0036] The elongation at break is determined in particular in the uniaxial quasi-static tensile test in accordance with the French standard NF S 94-167-2, whereby the test length and the test speed are used differently with 40 mm and 40 mm / min respectively.

[0037] The maximum tensile strength is determined in particular in the uniaxial quasi-static tensile test in accordance with the French standard NF S 94-167-2, whereby the test length and test speed are used differently, namely 40 mm and 40 mm / min respectively. Different versions of the cell culture scaffold, whether in a multi-layered arrangement of the mesh or made of plied filament yarns, can exhibit different mechanical properties such as tensile strength or elongation strength.

[0038] A cell culture scaffold formed from plied filament yarns can exhibit a maximum tensile strength in the production direction of the braid of at least 50 N per mm of the braid in the transverse direction, preferably at least 100 N per mm, more preferably at least 150 N per mm, and a tensile strength in the transverse direction to the production direction of the braid that is at least 80% lower than the tensile strength in the production direction of the braid. Such anisotropic properties can advantageously mimic the mechanical properties of anisotropic body tissues. Furthermore, a cell culture scaffold formed from plied filament yarns can exhibit an elongation at break in the range of > 10% to < 150%, preferably in the range of > 10% to < 80%, more preferably in the range of > 10% to < 50%.Multi-layered cell culture scaffolds can achieve good strengths, thus enabling the use of structures that are morphologically similar to natural tendon structures in preclinical or clinical studies.

[0039] In embodiments, a single-layer cell culture scaffold made of plied monofilament yarns can have a maximum tensile strength in the production direction of the braid of at least 50 N per mm of the braid in the transverse direction, preferably at least 100 N per mm, more preferably at least 150 N per mm. In particular, a single-layer cell culture scaffold made of plied monofilament yarns can have a maximum tensile strength in the production direction of the braid of at least 50 N per mm of the braid in the transverse direction, preferably at least 100 N per mm, more preferably at least 150 N per mm, and an elongation at break in the range of > 10% to < 150%, preferably in the range of > 10% to < 80%, more preferably in the range of > 10% to < 50%.

[0040] A multilayered arrangement of the mesh can exhibit a maximum tensile strength in the production direction of the mesh of at least 200 N per mm of the mesh in the transverse direction, preferably at least 300 N per mm, more preferably at least 400 N per mm, and a direction-dependent tensile strength in the transverse direction to the production direction of the mesh that is at least 80% lower than the tensile strength in the production direction of the mesh. Furthermore, a multilayered arrangement of the mesh can exhibit an elongation at break in the range of > 10% to < 150%, preferably in the range of > 10% to < 80%, more preferably in the range of > 10% to < 50%. Multilayered cell culture scaffolds can achieve high strength, thus enabling the use of structures morphologically similar to natural tendon structures in preclinical or clinical studies.

[0041] Overall, advantageous combinations of tensile strength (primary stability), stiffness, viscoelastic properties, porosity, and mean pore size of the mesh can be provided, particularly for the cultivation of ligament and tendon cells. Specifically, by means of a layered or multilayered arrangement of the mesh, especially when made of polycaprolactone or its copolymers, the mechanical properties of body tissues such as tissues of the vascular or musculoskeletal system, in particular tensile strength, stiffness, elasticity, and fatigue strength, as well as degradation kinetics adapted, for example, to a healing process, can be advantageously replicated for cell culture. In particular, appropriate elongation can be set for cell cultures of tendon and ligament tissue.

[0042] In some embodiments, the filament yarns are made of polycaprolactone or its copolymers with polyhydroxyacetic acid (polyglycolic acid, PGA), polylactide (PLA), polyhydroxybutyric acid (PHB), or mixtures thereof. Polycaprolactone (PCL) is a biodegradable polyester. Gam-based scaffolds made of polycaprolactone or its copolymers are therefore advantageously resorbable. This is also beneficial for laboratory consumables such as cell culture materials and their disposal. In particular, the use of polycaprolactone of especially high purity, for example, "medical grade," is advantageous for cell culture applications, as this can improve the interrelationship of the results obtained in cell culture.

[0043] Polycaprolactone is non-toxic and exhibits very high ductility as well as good chemical and solvent resistance. Polycaprolactone is also readily processable with many other plastics. In particular, copolymers with polylactic acid (PLA) or polyglycolide (PGA) can be readily produced by spinning processes. Preferably, the polycaprolactone monomer content is > 90%, more preferably > 95%, based on 100% monomers. Specifically, the polycaprolactone monomer content can be in the range of > 90% to < 99%, more preferably in the range of > 95% to < 98%, based on 100% of the monomers used.

[0044] In particular, fibers made of polycaprolactone and its copolymers are well-suited to supporting slowly regenerating tissue in cell culture. A significant advantage of yarn-based cell culture scaffolds made of polycaprolactone or its copolymers is that they are morphologically, mechanically, and in terms of degradation kinetics adapted to clinical applications, and can also be dimensioned for use in conventional well plates. Braided structures made of polycaprolactone and its copolymers, in particular, have proven to be highly effective in cell culture.

[0045] In various embodiments, the filament games exhibit the following properties

[0046] - Monofilaments with a fiber diameter in the range of > 30 pm to < 1 mm, preferably in the range of > 50 pm to < 500 pm, preferably in the range of > 80 pm to < 250 pm, and / or

[0047] - Multifilament yarns have a fiber diameter of the individual fibers in the range of 0.5 pm to < 150 pm and / or a fineness in the range of > 8 dtex to < 9000 dtex, preferably in the range of > 20 dtex to < 2000 dtex, preferably in the range of > 60 dtex to < 600 dtex, and / or - monofilament yarns or multifilament yarns have a tensile strength of at least 250 MPa, preferably at least 500 MPa, preferably at least 800 MPa, and / or - monofilament yarns or multifilament yarns have an elongation at break in the range of > 10% to < 200%, preferably in the range of > 10% to < 50%, preferably in the range of > 10% to < 30%.

[0048] Here, the unit 1 dtex (decitex) = 1 g / 10,000 m. The fineness for monofilament yarns was determined according to DIN EN 13392:2001. The fineness for multifilament yarns was determined according to DIN EN ISO 2060:1995. The tensile strength was determined by the quasi-static uniaxial tensile test, for monofilament yarns according to DIN EN 13895 and for multifilament yarns according to DIN EN ISO 2062. The elongation at break was determined by the quasi-static uniaxial tensile test, for monofilament yarns according to DIN EN 13895 and for multifilament yarns according to DIN EN ISO 2062.

[0049] Overall, the fibers exhibit a favorable combination of tensile strength (primary stability), stiffness, viscoelastic properties, porosity, and medium pore size.

[0050] In some embodiments, the fiber cross-section of the filaments is round or profiled, in particular star-shaped. Such cross-sectional shapes allow for further modification of the mechanical properties of the resulting braid.

[0051] In certain embodiments, the braid exhibits an undulation, preferably of a regular pattern. The term "undulation" of the fibers describes the fact that the fibers in the braid are arranged in a wave-like manner. This undulation arises, for example, from the use of a circular braiding machine on which the spools containing the fibers move along two intersecting sinusoidal paths. The undulation of the braid results from this predetermined movement. A repeating, regular braid accordingly exhibits a regular undulation. Unless otherwise stated, the technical and scientific terms used have the meanings commonly understood by a person skilled in the art in the field to which this invention belongs.

[0052] Examples that serve to illustrate the present invention are given below.

[0053] Example 1

[0054] Production of a single-layer textile cell culture scaffold from a mesh of plied monofilament amentgam

[0055] 1.1 Production of monofilament yarn

[0056] Polycaprolactone polymer pellets (Capa® 6800) were processed into monofilaments using a single-screw extruder spinning machine (Fourne Polymertechnik GmbH, Alfter, Germany). The processing temperature was 170–222 °C. The material was extruded through a circular spinneret (0.5 mm diameter, 2 L / D), quenched in a water bath, drawn using three pairs of dies, and then wound (SAHM 260XE, Georg Sahm GmbH & Co. KG, Eschwege, Germany). The draw ratio was 9.25.

[0057] 1.2 Production of a plied yarn

[0058] To prepare for the braiding process, the monofilaments were rewound on the USP300M rewinding machine (Herzog GmbH, Oldenburg, Germany). The material was plied using a creel with the appropriate number of monofilament spools. Nine monofilament spools were used, which were then joined together in the rewinding machine.

[0059] Mechanical characterization of the Gams: The fineness of the filaments (1 dtex = 1 g / 10,000 m) was measured according to DIN EN 13392 using 10 m long filament segments. The fineness of the filaments was 276 dtex.

[0060] The maximum tensile force, tensile strength, and elongation at maximum tensile force were determined in uniaxial tensile tests (STATIMAT 4U, Textechno Herbert Stein GmbH & Co. KG, Mönchengladbach, Germany) according to DIN EN 13895. For material efficiency, the gauge length and test speed were set to 100 mm and 100 mm / min, respectively. The test was performed under standard textile climate conditions according to DIN EN ISO 139. The maximum tensile force was 20 N. The tensile strength was 827 MPa. The elongation was 24.9%.

[0061] 1.3 Production of the braided structure and assembly

[0062] The scaffolds were produced using a circular braiding machine (horizontal circular braiding machine HS80 / 48 from Körting Nachfolger Wilhelm Steeger GmbH & Co. KG, Wuppertal) with 48 bobbins. The spring force used was approximately 141 g. A single-layer circular braid was produced, with each yarn spool containing a 9-ply monofilament, resulting in a total of 432 threads across the 48 yarn spools. The bobbin speed was 30 rpm. A braiding point spacing of 17 cm (measured from the bobbins) was set, and the braid was drawn off at a rate of 1.8 pixels / cm. The cell culture scaffolds were then cut from the continuous braid using laser cutting (Eurolaser GmbH, Lüneburg / Germany) to diameters suitable for standard 96- and 24-well plates.

[0063] 1.4 Characterization of the framework

[0064] The framework dimensions were determined using calipers in two directions, both stress-free and under a force of 2 N. The height of the braid was 4.112 mm stress-free and 3.017 mm under a force of 2 N. The width of the braid transverse to the production direction was 19.765 mm stress-free and 17.186 mm under a force of 2 N. The braid was mechanically characterized at a length of 170 mm in the production direction. The mechanical characterization of the braided framework was carried out in a uniaxial tensile test according to NF S 94-167-2. For this purpose, a universal testing machine (Zmart Pro, ZwickRoell GmbH & Co. KG, Ulm, Germany) was used. The clamping distance of the specimens was 40 mm, and the test was performed at a traverse speed of 40 mm / min.The samples were prepared with load-bearing elements made of cardboard and two-component adhesive (Araldite® 2011, Huntsman, The Woodlands, TX, USA) to prevent slippage. To improve the penetration of the two-component adhesive into the samples, they were pre-treated for 5 minutes using a low-pressure plasma process. The Pico low-pressure plasma system (Diener Electronics GmbH & Co. KG, Ebhausen, Germany) with argon gas was used for this purpose. A clamping pressure of 10 bar and a 20 kN load cell were used for the test. The test was performed under standard textile climate conditions according to DIN EN ISO 139. The direction-dependent tensile strength was 83 MPa. The maximum tensile force was 197 N per mm of width under 2 N preload. The elongation at break was 106%.

[0065] Example 2

[0066] Production of single-layer textile cell culture scaffolds from braids of multi-ply monofilament mesh with different ply ratios

[0067] 2.1 Production of monofilament yarn and mechanical characterization

[0068] The fabrication of monofilament gam was carried out using two approaches as described in Example 1.1. The mechanical characterization of the gam was also performed as described in Example 1.

[0069] Regarding fineness and diameter, textile technology typically specifies the fineness Tt of filaments (1 dtex = 1 g / 10,000 m). For monofilaments, specifying the diameter D is also common. Assuming a circular cross-section and density, the diameter can be calculated from the fineness as follows:

[0070] D = 11.3 √(Tt / p) P ); Tt in dtex

[0071] The density of the polycaprolactone Capa® 6800 is 1.14 g / cm³. 3 .

[0072] The following Table 1 summarizes the results of the mechanical characterization of the yarn of the two approaches VI and V2.

[0073] Table 1: Results of the mechanical characterization

[0074]

[0075] 2.2 Production of four-ply and nine-ply braids

[0076] To prepare for the braiding process, the monofilaments were rewound on the USP300M rewinding machine (Herzog GmbH, Oldenburg, Germany). The material was plied using a creel with the appropriate number of monofilament spools. Four or nine monofilament spools were used, which were then joined together in the rewinding machine.

[0077] The frames were produced using a circular braiding machine (horizontal circular braiding machine HS80 / 48 from Körting Nachfolger Wilhelm Steeger GmbH & Co. KG, Wuppertal) with 48 bobbins. The spring force used was approximately 58 g (4-ply) and 128 g (9-ply). A single-layer circular braid was produced, with each spool of yarn containing a 4-ply or 9-ply monofilament (of the type described above), so that with 12 or 9 bobbins, respectively, the resulting spools contained 12 or 128 g of braid.

[0078] 48 spools of yarn resulted in a total thread count of 48 or 432. The bobbin winder speed was 30 rpm. A braiding point spacing of 8 cm (4-ply) or 17 cm (9-ply) (measured from the braiding ring or the bobbins) was set and the stitches were pulled off at a rate of 4.5 pixels / cm (4-ply) or 2.1 pixels / cm (9-ply).

[0079] 2.3 Characterization of the framework

[0080] The frame dimensions were determined using calipers in two directions, both stress-free and under a force of 2 N, as described in Example 1.4 "Characterization of the Frame". The height of the mesh was 1.45 mm stress-free and 1.29 mm under a force of 2 N (9-ply frame), and 0.62 mm and 0.59 mm under a force of 2 N (4-ply frame). The width of the mesh transverse to the production direction was 18.4 mm stress-free and 15.1 mm under a force of 2 N, and 3.38 mm and 2.39 mm under a force of 2 N (4-ply frame). Table 2 below summarizes the results of the mechanical characterization of the 4-ply and 9-ply frames.

[0081] Table 2: Results of the mechanical characterization of the scaffolds

[0082]

[0083] Mechanical characterization in production direction

[0084] The mechanical characterization of the braided framework was performed in a uniaxial tensile test in accordance with NF S 94-167-2. A universal testing machine (Zmart Pro, ZwickRoell GmbH & Co. KG, Ulm, Germany) was used for this purpose. The clamping distance of the specimens differed from the standard test: 30 mm (for the 9-ply frameworks) and 40 mm (for the 4-ply frameworks). The test was carried out at a traverse speed of 30 mm / min (for the 9-ply frameworks) and 40 mm / min (for the 4-ply frameworks). The specimens were prepared with load-bearing elements made of cardboard and two-component adhesive (Araldite® 2011, Huntsman, The Woodlands, TX, USA) to prevent slippage. To improve the penetration of the samples with the two-component adhesive, the samples were pretreated for 5 minutes using a low-pressure plasma process. For this purpose, the Pico low-pressure plasma system (Diener Electronics GmbH & Co.) was used.KG, Ebhausen, Germany) with argon gas. A clamping pressure of 10 bar and a 20 kN load cell (for the 9-ply frames) or a 5 kN load cell (for the 4-ply frames) were used for the test. The test was carried out under standard textile climate conditions according to DIN EN ISO 139. Table 3 below summarizes the results of the mechanical characterization of the 4-ply and 9-ply frames in the production direction.

[0085] Table 3: Results of the mechanical characterization of the 4-fold and 9-fold scaffolds in product direction!

[0086]

[0087] Mechanical characterization in the transverse direction

[0088] The mechanical characterization in the transverse direction was carried out on a tensile testing machine (Z2.5, ZwickRoell GmbH & Co. KG, Ulm, Germany) in accordance with ISO 7198. The test was performed on the 9-ply frame under standard climate conditions according to DIN EN ISO 139 with a specimen length of 20 mm, a testing speed of 50 mm / min, and a 20 N force transducer. The clamping length in the starting position was 10 mm, and the parallel specimen length was 15.94 mm. The maximum tensile force in the transverse direction of the frames was 4.8 ± 0.58 N. This shows that the direction-dependent tensile strength in the transverse direction to the production direction is at least 80% lower than the tensile strength in the production direction of the braid.

Claims

Patent claims 1. Textile cell culture framework comprising a variety of monofilament yarns or multifilament yarns forming a three-dimensional structure, wherein the three-dimensional structure is formed from a braid, and wherein the cell culture framework comprises multiple layers and / or plied monofilament yarns or multifilament yarns.

2. Textile cell culture scaffold according to claim 1, characterized in that the cell culture scaffold is a single-layer cell culture scaffold formed from multi-layered monofilament scaffolds.

3. Textile cell culture framework according to claim 1 or 2, characterized in that the plied monofilament yarns have a plying in the range of > 2 to < 100, preferably in the range of > 2 to < 20.

4. Textile cell culture framework according to one of the preceding claims, characterized in that the cell culture framework comprises a thread count in the range of > 3 to < 3000, preferably in the range of > 20 to < 1000, preferably in the range of > 200 to < 800, mono- and / or multifilament yarns.

5. Textile cell culture framework according to one of the preceding claims, characterized in that the monofilament yarns or multifilament yarns are arranged in the production direction of the braid at an angle α in the range of > 4° to < 60°, preferably in the range of > 8° to < 30°, to each other.

6. Textile cell culture framework according to one of the preceding claims, characterized in that the cell culture framework has a circular shape in the plane of the production direction of the braid, wherein the filament yarns are preferably only connected to each other in the edge region of the circular surface and / or wherein the cell culture framework has a height in the range of > 1 mm to < 12 mm in the direction perpendicular to the production direction of the braid for a multi-layered arrangement, or has a height in the range of > 100 pm to < 4 mm for a cell culture framework formed from plied filament yarns.

7. Textile cell culture scaffold according to one of the preceding claims, characterized in that the cell culture scaffold has the following properties: - a porosity in the range of > 40% to < 90%, preferably in the range of > 60% to < 90%, preferably in the range of > 75% to < 90%, and / or - a mean pore size in the range of > 10 pm to < 500 pm, preferably in the range of > 50 pm to < 300 pm, preferably in the range of > 100 pm to < 250 pm, wherein in particular at least 50%, preferably at least 65%, preferably at least 80% of the pores between the filament yarns have a pore size in the range of > 10 pm to < 500 pm, preferably in the range of > 50 pm to < 300 pm, preferably in the range of > 100 pm to < 250 pm.

8. Textile cell culture scaffold according to one of the preceding claims, characterized in that the cell culture scaffold has the following mechanical properties: - a direction-dependent tensile strength, wherein the tensile strength in the transverse direction to the production direction of the braid is at least 80% lower than the tensile strength in the production direction of the braid, and / or - an elongation at break in the range of > 10% to < 150%, preferably in the range of > 10% to < 80%, preferably in the range of > 10% to < 50%, and / or - a maximum tensile force in the production direction of the braid of at least 200 N per mm of the braid in the transverse direction, preferably at least 300 N per mm, preferably at least 400 N per mm, for a multi-layered arrangement of the braid, or - a maximum tensile force in the production direction of the braid of at least 50 N per mm of the braid in the transverse direction, preferably at least 100 N per mm, preferably at least 150 N per mm, for a cell culture scaffold formed from plied filament yarns.

9. Textile cell culture framework according to one of the preceding claims, characterized in that the filament yarns are formed from polycaprolactone or its copolymers with polyhydroxyacetic acid, polylactide, polyhydroxybutyric acid or mixtures thereof, wherein the proportion of polycaprolactone monomer is preferably > 90%, preferably > 95%, based on 100% monomers.

10. Textile cell culture framework according to one of the preceding claims, characterized in that the filament yarns have the following properties: - Monofilament games have a fiber diameter in the range of > 30 pm to < 1 mm, preferably in the range of > 50 pm to < 500 pm, more preferably in the range of > 80 pm to < 250 pm, and / or - Multifilament games have a fiber diameter of the individual fibers in the range of > 0.5 pm to < 150 pm and / or a fineness in the range of > 8 dtex to < 9000 dtex, more preferably in the range of > 20 dtex to < 2000 dtex, more preferably in the range of > 60 dtex to < 600 dtex, and / or - Monofilament yarns or multifilament yarns with a tensile strength of at least 250 MPa, preferably at least 500 MPa, preferably at least 800 MPa, and / or - Monofilament or multifilament yarns have an elongation at break in the range of > 10% to < 200%, preferably in the range of > 10% to < 50%, preferably in the range of > 10% to < 30%.

11. Textile cell culture framework according to one of the preceding claims, characterized in that the fiber cross-section of the filaments is round or profiled, in particular star-shaped, and / or the mesh has an undulation, preferably regular.

Images