Muscle Assist Membrane

Abstract

The invention provides a muscle membrane (1) intended to be applied to a muscle of a human or animal body, said membrane (1) being capable of at least partially enveloping the muscle, the muscle comprising fibers covered by an external tissue, the membrane, when in position, having a geometry identical to that of the muscle. This membrane (1) is characterized in that it has anisotropic behavior so as to reproduce the mechanical behavior of the muscle, the membrane (1) comprising: - a matrix (7) made of a biocompatible material having an elasticity similar to that of the external tissue of the muscle, - one or more reinforcing bands (8) attached to the matrix (7), each band (8) being made of a biocompatible material having an elasticity similar to that of the fibers it covers and each band (8) being oriented according to the requirements for stiffening the membrane (1) and according to the expected muscle correction. Figure for the abstract: Figure 1

Description

Title of the invention: Muscle Assistance Membrane Technical field of the invention

[0001] The invention relates to a membrane intended to be applied to a muscle of a human or animal body, the membrane being able to at least partially envelop the muscle.

[0002] The invention also relates to a method for manufacturing such a membrane, by 3D printing.

[0003] The invention also relates to a prosthesis of a muscle, of the cardiac prosthesis or muscle prosthesis type, formed by such a membrane.

[0004] The invention also relates to an orthosis, of the plantar orthosis or forearm orthosis type, formed by such a membrane.

[0005] And finally, the invention relates to the use of such a membrane on a muscle of a human or animal body.

[0006] Also, the technical field of this innovation concerns the health sector, and more particularly bioprostheses and bioorthoses. Technical background

[0007] Whether it is the heart or a skeletal muscle, when a muscle is atrophied or damaged, the movement for which it is intended will be prevented or compensated by biological adaptation (e.g., fibrosis, muscle extension) or physiological adaptation (e.g., compensation of the movement by the body or by neighboring muscles).

[0008] Case of the cardiac muscle

[0009] Myocardial infarction is caused primarily by an obstruction of the coronary arteries that supply oxygen to the heart muscle, causing a lack of oxygen (ischemia) in certain regions of the heart muscle. Ischemia of the heart muscle does not irreversibly cause an infarction, but can lead from mild heart failure to cardiogenic shock. This results in impaired contraction and relaxation of the heart muscle (hypokinesis or akinesia) in certain regions of the heart.

[0010] A myocardial infarction will be diagnosed when the evaluation indicates that there is necrosis of certain regions of the heart muscle following ischemia. The infarction most often affects the left ventricle, but the right ventricle can also be affected.

[0011] Myocardial infarction leads to biological and physiological changes in the heart (remodeling). Thus, changes in the dimensions, thickness, and geometry of the left ventricle are observed. The risk of long-term mortality is associated to the extent of this remodeling. A heart attack can also lead to mechanical complications, heart failure, and heart rhythm disturbances that pose a risk of sudden death. Even with treatment, a myocardial infarction increases the risk of mortality by 15%. Patient care often involves intensive treatments, regular medical follow-up, lifestyle changes, surgery, or the implantation of a cardiac defibrillator or pacemaker.

[0012] Biomedical materials intended for epicardial application have been studied intensively in recent years for various therapeutic purposes.

[0013] Most biomaterials intended for epicardial applications are manufactured in the form of membranes or patches.

[0014] These are, for example, thin membranes containing various biological properties and applied directly to the target epicardial region.

[0015] These are also hemostatic patches, creating an interface to prevent severe tissue adhesion after cardiac surgery.

[0016] Or cardiac patches delivering cell therapy after a myocardial infarction.

[0017] However, research in this area has mainly focused on the biological or therapeutic behavior of these biomaterials, largely ignoring the analysis of their mechanical interaction with the heart.

[0018] Indeed, the geometry and isotropic behavior of the membranes and patches are not well suited to the movement of the myocardial wall. The movement of the myocardial wall during systole and diastole produces a complex force in different directions.

[0019] Once the biomedical material adheres to the epicardium, it undergoes the same cyclic deformation and stress caused by the heartbeat as the epicardium. The structure of the muscle fibers also differs from one area to another, thus exerting a mechanical force in different directions during the cardiac cycle.

[0020] Most epicardial biomaterials are manufactured in the form of isotropic membranes or patches that cannot adapt to the specific structure of the heart muscle fibers, thus potentially applying an inappropriate force to the epicardium, which could possibly cause a restriction effect.

[0021] Current membranes and patches can therefore have a mechanical influence on the heart, which is not necessarily desirable since it goes against the natural movement of the organ.

[0022] Case of skeletal muscle

[0023] In the case of skeletal muscles, whose function is primarily the mobility of the limbs, several types of injuries can be observed (stretching, straining, (tearing, atrophy, etc.). In the case of disabled individuals, it is a serious injury to the nervous system and / or muscle, for example, that leads to a drastic reduction in limb movement, even immobility. This immobility ultimately results in muscle wasting and atrophy. The loss or reduction of limb mobility is not compensated for, or is only with great difficulty.

[0024] Orthoses exist that correct movement when the muscle is no longer capable of it. The construction of the orthosis can be adapted to the individual's needs (for example: more rigidity, less torsion, more traction, etc.) to compensate for reduced mobility, facilitate movement, and / or reduce pain related to their disability.

[0025] However, current orthoses are designed from a single material, with isotropic behavior. The orthosis does not adapt to the different regions it surrounds, to the different fibrous orientations that vary from one point to another within the organ. A textile orthosis made of synthetic fibers only stiffens movement in the direction of tissue extension, which does not necessarily correspond to the directions of all the muscle fibers surrounded by the orthosis.

[0026] The objective of the present invention is to design a muscle membrane made from compatible materials of natural or synthetic origin, intended to reduce compensation and / or repair damaged muscles, whether cardiac or skeletal. This membrane must be able to follow the complex movement of the muscle without mechanically influencing the desired movement and correcting harmful movements. It must therefore be able to deform in a manner similar to the expected deformation of the muscle in action. Summary of the invention

[0027] This goal is achieved by means of a muscle membrane intended to be applied to a muscle of a human or animal body, said membrane being able to at least partially envelop the muscle, the muscle comprising fibers covered with an external tissue, the membrane in position having a geometry identical to that of the muscle.

[0028] This membrane is characterized in that it has anisotropic behavior so as to reproduce the mechanical behavior of muscle, the membrane comprising:

[0029] - a matrix designed in a biocompatible material having an elasticity similar to that of the external tissue of the muscle,

[0030] - one or more reinforcing strips associated with the matrix, each strip being designed in a biocompatible material having an elasticity similar to that of the fibers it covers, and each strip being oriented according to the needs of stiffening the membrane.

[0031] The main idea of ​​this invention is to design a biomaterial membrane that takes into account not only the geometry but also the mechanical properties of the muscle, namely the external muscle tissue and the muscle fibers.

[0032] Indeed, this membrane is designed to be placed around a muscle, enveloping it very precisely, with an exact geometry.

[0033] This membrane is designed to deform with the muscle by exerting an appropriate mechanical force on it. It forms a kind of double skin, which follows and corrects the natural movement of the muscle.

[0034] This membrane is directly attached to the external tissue of the muscle, and therefore must primarily follow and correct the movement of this external tissue. It is a cellular tissue. In the case of skeletal muscle, this external tissue is the skin. In the case of cardiac muscle, this external tissue is the epicardium.

[0035] More specifically, the membrane matrix is ​​in direct contact with the external tissue. The matrix must therefore reproduce the mechanical properties of this external tissue.

[0036] By mechanical property, we mean the elasticity of fabrics and fibers.

[0037] The first biocompatible material forming the matrix has an elasticity corresponding to that of the external tissue.

[0038] The matrix is ​​designed in a first biocompatible material exhibiting a first elasticity similar to the elasticity of the external tissue, this gives the membrane an initial isotropic mechanical behavior.

[0039] This can be modified by combining reinforcement strips of different elasticities or of identical elasticity but locally increasing the geometry of the membrane. These reinforcements modify the isotropic behavior of the membrane into an anisotropic behavior, and more particularly transverse isotropic or orthotropic behavior.

[0040] It is advantageous not to limit oneself to the external tissue, but also to take into account the orientations of the fibers located just behind the external tissue, because they contribute strongly to the movement of the organ in action.

[0041] Muscle elasticity varies from one area to another depending on the fibrous orientations.

[0042] Fibers with the same orientation will have the same elasticity.

[0043] It is therefore essential to analyze the orientation and elasticity of the fibers locally, in order to be able to precisely design the mechanical properties of the membrane zone by zone.

[0044] After precise analysis of the muscle fibers, several types of zones are defined: - zones which must be reinforced, or encircled, according to the pathology or according to the care which we wish to provide via the membrane. - areas where the direction of fiber extension is similar to the direction of main extension of the external tissue: this means in particular that the elasticities are similar. - areas where the direction of fiber extension differs from the main extension direction of the external tissue: this will be called the secondary extension direction. This means that the elasticities are different.

[0045] The membrane must adapt to all these areas thanks to the reinforcement bands associated with the matrix and which serve to reinforce and orient the membrane in the best possible way, adapting as much as possible to the muscle.

[0046] The orientation of the membrane is carried out according to the needs for stiffening of the membrane, which depend on the muscular correction that one also wishes to give to the muscle.

[0047] According to one possible configuration, the matrix is ​​created first and the reinforcing strips are added to the matrix in a second step. They are then fixed to the matrix by fastening means. In this case, there is a superposition of two layers: namely the matrix layer, and the strip layer.

[0048] The means of attachment can be of the type overmolding, clips, gluing, etc.

[0049] When the strips are superimposed on the matrix, two superimposed layers are obtained forming a reinforcement zone, that is to say a zone where the matrix is ​​rigidified.

[0050] Thanks to these reinforcement bands, the thickness of the membrane can be varied. The membrane will be thin on areas that are not to be impacted, and will be thicker on areas to be impacted, for example when it is a deficient area of ​​the muscle.

[0051] According to another possible configuration, the matrix and the reinforcing strips are created simultaneously during the manufacturing of the membrane. The material of the strips can be integrated into the matrix material during manufacturing to, in a sense, "fill gaps" and provide a different mechanical characteristic in a more localized manner within the membrane.

[0052] As previously stated, each band is made of a material with a specific elasticity. Thus, several bands with different materials are combined with the matrix, so as to obtain a membrane that best corrects the mechanical behavior of the muscle and / or organ.

[0053] According to the invention, some strips are made of the same material as the matrix material, and some strips are made of a different material. It all depends on the desired elasticity of the strip.

[0054] The anisotropic behavior of the membrane can be obtained with the same material for the matrix and the reinforcing strips, or with different materials for the matrix and the strips. Generally, the presence of reinforcing strips modifies the mechanical behavior of the membrane, and makes it anisotropic, that is to say with properties that vary according to directions and areas.

[0055] Biocompatible materials are of natural or synthetic origin.

[0056] They are chosen from among other things latex, synthetic fibers, natural gums of the type chitosan, tamarind, alginate, gelatin, guar, xanthan gum, or mixtures of these gums, or even a polymer of the type polyacrylamide.

[0057] Natural gums have the particularity of being non-toxic and of exhibiting different viscosity properties depending on their nature and thus having a different rigidity after drying.

[0058] These materials are chosen taking into account the structural specificity of muscle tissue and the orientation of the fibers.

[0059] Preferably, the membrane is made from a mixture of chitosan and guar, or a mixture of chitosan and tamarind.

[0060] Preferably, each reinforcing band can be adapted to the needs, by choosing the material, the tension, and the orientation.

[0061] Each band thus presents a specific tension within the membrane.

[0062] By tension, we mean the tension applied between the two ends of the strip, fixed or integrated into the matrix.

[0063] By orientation we mean the orientation of the strip on the matrix in correlation with its positioning on the muscle.

[0064] The materials for the bands are chosen according to the desired anisotropy of the membrane, the bands are oriented according to the orientation of the fibers they cover, and the tension of the bands is applied according to the desired mechanical behavior of this area. The combination of these three parameters promotes the creation of a membrane that corrects the movement of the muscle it envelops.

[0065] Advantageously, the membrane is obtained by molding.

[0066] Advantageously, the membrane is obtained by weaving one or more fibers textiles.

[0067] Advantageously, the membrane is obtained by 3D printing. The muscle membrane is then produced using state-of-the-art technology.

[0068] Advantageously, the membrane has an internal surface suitable for coming into contact with the muscle, said internal surface being able to be functionalized.

[0069] This functionalization is achieved using controlled delivery systems containing or not active ingredients and / or biomolecules.

[0070] For example, such biological functionalization can be achieved by the integration of cells, growth factors, nutrients, and / or therapeutic agents.

[0071] The invention also relates to a method for manufacturing a membrane intended for use on a muscle of a human or animal body, comprising the following steps:

[0072] - CT scan of the muscle to be wrapped to define its external geometry, and the orientation of its fibers;

[0073] - modeling of the geometry, elasticity and extension directions of the membrane that must at least partially envelop the muscle;

[0074] - formation of a support taking the shape of the muscle;

[0075] - formation of the membrane from at least one biocompatible material for form the matrix and the reinforcing strips.

[0076] Thanks to this scanning technique, it is possible to personalize the membrane so that it conforms to the exact geometry of the patient's muscle.

[0077] The formation of the membrane can be carried out by any conventional technique, for example by molding, or by 3D printing with injection of the biocompatible material(s).

[0078] In the case of molding, a support in the form of a mold is first formed, and reproduces the exact shape of the muscle. Then, in a second step, the biocompatible material is poured into the mold, and the membrane is thus formed, conforming to the shape of the mold.

[0079] In the case of 3D printing, a support reproducing the exact shape of the muscle is printed simultaneously with the membrane, layer by layer, with membrane 1 covering the support. The material used for the support is not the same as that used for the membrane.

[0080] Thus the steps of forming the support (2) and the membrane (1) are carried out by 3D printing, the membrane (1) being printed simultaneously with the support (2).

[0081] The invention relates to a muscle prosthesis, of the cardiac or muscle prosthesis type, formed by a membrane as described above.

[0082] In this case, the membrane is deployed for example by a minimally invasive operation.

[0083] The membrane matrix will have an elastic behavior as close as possible to the extracellular tissue of the heart for the cardiac prosthesis.

[0084] Such a muscle-assisted cardiac prosthesis reproduces the shape and orientation of the heart's fibers, which have specific mechanical functions (elasticity). It makes it possible to reduce ventricular deformations (in particular enlargement) following an infarction, and / or to serve as an interface for the use of a mechanical exoskeleton or to repair damaged areas through membrane functionalization.

[0085] The invention also relates to a muscle orthosis, of the plantar orthosis or forearm orthosis type, formed by a membrane as described above.

[0086] The membrane matrix will have an elastic behavior as close as possible to the Skin for the orthosis. Thanks to its mechanical properties, the membrane corrects the movement when the muscle is no longer able to do so.

[0087] Finally, the invention relates to the use of a membrane, as described above, on a muscle, said membrane at least partially enveloping the muscle. Brief description of the figures

[0088] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0089] Fig. 1 is an example of a forearm orthosis.

[0090] Fig. 2 is another example of a forearm orthosis.

[0091] Fig. 3 shows the orthosis according to figures 1 and 2 in place on a forearm.

[0092] Figure 4 is a perspective view of a mold of an organ (in this case, the heart) on which a membrane is printed;

[0093] The [Fig.5] is a perspective view of a membrane (in this case a cardiac membrane) intended to be placed in position on an organ (in this case the heart);

[0094] Figures 6A, 6B, 6C illustrate the fibrous directions of an organ (in this case, a heart);

[0095] Figures 7A, 7B, 7C, 7D, 7E represent various stages in the creation of a cardiac membrane. Detailed description of the invention

[0096] In the following description, elements having an identical structure or analogous functions will be designated by the same references.

[0097] The invention relates to a membrane made of biocompatible material, suitable for at least partially enveloping a muscle of a human or animal body, in order to provide temporary and / or permanent functional correction.

[0098] In this detailed description, several examples of membrane will be presented.

[0099] Figures 1 to 3 correspond to examples of a forearm membrane used as an orthosis.

[0100] In [Fig. 1], the orthosis comprises a matrix 7 made of latex and synthetic fabric reinforcement bands 8 integrated into the matrix 7 during its manufacture. Other materials are also covered by the present invention.

[0101] In [Fig. 2], the orthosis comprises a matrix 7 made of latex and latex reinforcement bands 8 subsequently superimposed on the matrix 7. These bands 8 are attached to the matrix 7, here using clips. Other materials and fastening means fall within the scope of the present invention.

[0102] During fixation, the orientation of the bands 8 is chosen so as to correspond to the desired correction according to the orientation of the muscle fibers located below when the orthosis is put in place.

[0103] During fastening, the tension applied between the two ends of the band 8 is adjustable. To achieve this, the bands 8 are pre-drilled to form notches, and depending on the notch chosen for the clip, the band 8 will be more or less taut.

[0104] The bands 8 are attached to the matrix 7 at different heights (or locations) and thus give different intensities and orientations to the force applied to the forearm.

[0105] The orthosis thus manufactured in figures 1 and 2 has anisotropic behavior and corrects the movements of the injured muscle (example atrophied muscle).

[0106] The 8 reinforcing bands induce resistance on specific arm movements in order to allow the forearm to maintain a functional position and / or return to its initial position.

[0107] Figure 3 shows the orthosis of Figures 1 and 2 fitted to the forearm. This orthosis has an opening 9 for the thumb and an opening 10 for the elbow.

[0108] The membrane is manufactured here in a flat pattern, from a mold into which the latex is poured and then dried under controlled temperature. Hook and loop fasteners 11 are arranged on the longitudinal sides so that they can be joined together once the orthosis is positioned around the forearm. Other fastening means fall within the scope of the present invention, in particular a permanent assembly to form a sleeve-type orthosis.

[0109] Figures 4 to 6 relate to an example of a membrane used as a cardiac prosthesis.

[0110] The heart has a limited capacity for regeneration. Once the cardiomyocytes (the contractile cells of the heart muscle) of an adult heart are damaged, they are replaced by non-contractile fibrous scar tissue. The loss of the contractile capacity of cardiomyocytes leads to heart dysfunction and ultimately causes heart failure. A promising approach for the treatment of myocardial infarction is the application of two-dimensional (2D) or three-dimensional (3D) membranes.

[0111] The three-dimensional membrane according to the invention is made from a scan of a patient's heart in order to obtain a suitable geometry.

[0112] This scan allows us to obtain the exact dimensions of the heart. From this scan, we can define the exact dimensions of the membrane that will cover this heart.

[0113] The membrane must have a geometry that corresponds to the external shape of the heart, in order to fit it.

[0114] In order to be able to manufacture cardiac membranes exhibiting the characteristics With appropriate mechanical systems, it is necessary to study cardiac tissue.

[0115] A heart is represented in figure 6C.

[0116] Its cardiac tissue is shown in Figure 6A and is broken down into:

[0117] i) an epicardium 4 (which corresponds to an outer envelope)

[0118] ii) a myocardium 5 (which corresponds to muscle fibers, called myofibers)

[0119] iii) an endocardium 6 (which corresponds to an inner envelope).

[0120] The myocardium 5 is coiled and roughly forms an 8.

[0121] More specifically, a helical orientation of the myocardium 5 is observed, from the base (i.e. the upper part of Figure 6C) to the apex of the heart (i.e. the lower part in Figure 6C).

[0122] During the cardiac scan (Figure 6C), the different directions of fiber extension are identified. Indeed, when the cardiac muscle is stressed, it will stretch or contract according to the directions of the fibers.

[0123] In the case of the heart, as illustrated in Figure 6B, there are myofibers that extend along:

[0124] - a first extension direction, called the main extension direction, in such a way radial, symbolized by the arrow R;

[0125] - a second extension direction, called the secondary extension direction, in such a way longitudinal, symbolized by the arrow L.

[0126] It is noted here that the major part of the myocardium 5 has a radial fibrous orientation.

[0127] The zoom in Figure 6B illustrates the orientation of the myofibers on a longitudinally extending area of ​​the myocardium 5.

[0128] Moving upwards from the apex to the base, we observe that the fibers of myocardium 5 are oriented alternately longitudinally and radially.

[0129] There are variations in the elasticity of cardiac tissue depending on the elements considered (epicardium 4, myocardium 5 and endocardium 6), and also depending on the fibrous orientations of the myocardium 5.

[0130] These elasticity values ​​are measured, for example by nanoindentation. The reduced Young's modulus is measured as a function of the penetration depth of the penetrator on samples of cardiac tissue.

[0131] A certain elasticity value can be deduced for a certain fibrous orientation. Indeed, one elasticity value is obtained for the myocardium 5 with a longitudinal orientation of the myofibers, and another elasticity value is obtained for the myocardium 5 with a radial orientation of the myofibers.

[0132] A certain elasticity value is also obtained for epicardium 4 and endocardium 6.

[0133] So that the cardiac membrane 1 reproduces the mechanical behavior as closely as possible of the heart, it must be designed in one or more materials whose elasticity corresponds to that measured on cardiac tissue and on fibers.

[0134] Figures 4 and 5 illustrate a cardiac membrane 1. These figures will be described in more detail later in the description.

[0135] The cardiac membrane 1 mainly comprises a matrix 7 designed in a first material, and whose behavior is similar to that of the epicardium 4 of [Fig.6].

[0136] More specifically, a first biocompatible material is chosen which has an elasticity similar to that of epicardium 4. A first biomaterial is thus chosen whose mechanical properties are closest to those of epicardium 4, to make a matrix 7, which will then have a first direction of extension.

[0137] For the reinforcement bands 8, the second biocompatible material is chosen, and they are positioned perpendicular to the fibers covered over all or part of the organ according to the movement correction requirements.

[0138] For the creation of a cardiac membrane in the form of a sock, a base 2 is manufactured, as illustrated in Figures 4 and 7A, in plastic by 3D printing following the scan of the heart, then the membrane 1 is cast on the base 2 to take the shape of the heart, as illustrated in Figures 4 and 7B.

[0139] For example, the matrix 7 is designed in alginate, chitosan and guar gum, and the reinforcing bands 8 of the membrane 1 are designed with the same material at a concentration, ratio, and / or oriented structure, more or less alveolar as shown in Figures 7C, 7D and 7E, adapted to the expected stiffening.

[0140] Figure 7E shows in particular the positioning of such oriented alveolar structures, which are arranged in precise directions according to the direction of extension of the fibers they cover, L or R.

[0141] It is also possible to design the membrane by 3D (three-dimensional) printing.

[0142] To give it this exact geometry, it is necessary to print a base and the membrane at the same time.

[0143] Thus, as illustrated in [Fig.4], following the heart scan, the base 2 reproducing the external shape of the heart and the membrane 1 are printed layer by layer. This base 2 is printed with a plastic material which allows the base to be rigid and to serve as a support for the printing of the membrane 1.

[0144] The cardiac membrane 1 is printed in one or more materials which allow it to be more or less flexible after printing. The latter ultimately conforms perfectly to the external shape of the heart 3, as illustrated in [Fig.5].

[0145] Each layer of the membrane 1 is printed from the two materials of the matrix 7 and the reinforcement 8, i.e., with the two biocompatible materials. thus obtains cardiac membrane 1 as illustrated in [Fig.5].

[0146] The reinforcement of the membrane 1 is obtained by the organization of the reinforcements 8. The orientation, the nature of the reinforcements 8 and their number are defined by the analysis of the scan of the failing organ.

[0147] When it is desired to reinforce only one area of ​​the matrix 7, then the reinforcement bands 8 are printed in the matrix 7.

[0148] A membrane 1 with anisotropic behavior is obtained, composed of two interlaced materials, forming one or more localized reinforcements. These reinforcing bands 8 constitute means of stiffening the membrane 1.

[0149] When it is desired to modify the orientation of the membrane 1 in different areas, then reinforcing bands 8 are locally printed on the matrix 7, with a biomaterial adapted to the desired orientation.

[0150] In the example shown, the matrix 7 has an elasticity similar to the longitudinal elasticity of the myocardial fibers. We will therefore use the same first biomaterial to print this matrix 7 and a second material in the form of reinforcing strips 8 whose elasticity corresponds to the radial elasticity of the myocardial fibers with an orientation perpendicular to the fibers, see [Fig.7].

[0151] From the moment strips 8 are printed in the form of a structure made up of alveoli of varying sizes [Fig. 7], a cardiac membrane 1 with anisotropic behavior is obtained. The two materials used thus contribute to obtaining the mechanical behavior of the cardiac membrane 1, which is compatible with the heart being treated.

[0152] The matrix 7 and the reinforcing bands 8 can be designed with polymer-based materials.

[0153] According to the invention, 3D printing ink formulations based on natural gums have been developed for the manufacture of these anisotropic cardiac membranes.

[0154] Four ink formulations based on chitosan (CH), chitosan / guar gum (CH-GG), chitosan / tamarind gum (CH-TG) and alginate / polyacrylamine (AL-PO) have been developed.

[0155] In order to improve the printing of these four inks, gelatin may be added to the composition of the inks.

[0156] The first one is composed of chitosan 90 / 10 (90% degree of deacetylation, 10 mPa.s average viscosity) at a concentration of 2% called CH.

[0157] The second ink is composed of a mixture (1:1 ratio) of chitosan (2%) and Guar gum (2%) called CH-GG.

[0158] The third ink is composed of a mixture (1:1 ratio) of chitosan (2%) and Tamarin gum (2%) called CH-TG.

[0159] The fourth ink is composed of a mixture (8:1 ratio) of alginate (12.25%) and of polyacrylamine (1.75%).

[0160] A printed membrane 1 based on CH-GG or CH-TG exhibits elasticity similar to that of the myocardium 5 with a radial orientation of the fibers.

[0161] A printed membrane 1 based on CH or based on AL-PO exhibits an elasticity similar to that of epicardium 4 and that of myocardium 5 with a longitudinal orientation of the fibers.

[0162] Thus, preferably, the first biocompatible material is CH or AL-PO, and the second biocompatible material is CH-GG or CH-TG.

[0163] Preferably, all 3D constructions were printed using an Envisiontec bioprinter with an inner diameter needle of 250 mm and a constant speed of 5 mm / s, while the pressure was adapted to each formulation: approximately 0.6 bar for CH, 0.8 bar for CH-TG, and 1.0 bar for CH-GG. These parameters can be transposed and adjusted depending on the printer used.

[0164] To be effective in restoring cardiac function, membranes 1 must:

[0165] i) have mechanical properties similar to those of the core, as seen previously,

[0166] and ii) optionally release therapeutic ingredients such as growth factors and / or biomolecules.

[0167] Indeed, the functionalization of membrane 1 falls within the scope of the present invention. In this case, the inner wall of membrane 1 in contact with the heart is functionalized, at least in the areas to be treated.

[0168] Several applications are possible with such membranes 1.

[0169] Indeed, these membranes 1 can be used as active cardiac prostheses (for example with the integration of cardiomyocytes) and passive cardiac prostheses, made of polymers.

[0170] These membranes 1 can be used as muscle prostheses, or as orthoses, for example for elite athletes in para-sports. This could be a forearm orthosis.

[0171] The configurations shown in the cited figures are only possible examples, by no means limiting, of the invention which on the contrary encompasses variants of forms and designs within the reach of a person skilled in the art.

Claims

Demands

1. Muscle membrane (1) intended to be applied to a muscle of a human or animal body, said membrane (1) being able to at least partially envelop the muscle, the muscle comprising fibers covered by an external tissue, the membrane (1) in position having a geometry identical to that of the muscle, said membrane being characterized in that it has anisotropic behavior so as to reproduce the mechanical behavior of the muscle, the membrane (1) comprising: - a matrix (7) designed in a biocompatible material having an elasticity similar to that of the external tissue of the muscle, - one or more reinforcing bands (8) associated with the matrix (7), each band (8) being designed in a biocompatible material having an elasticity similar to that of the fibers it covers and each band (8) being oriented according to the requirements for stiffening the membrane (1).

2. Membrane (1) according to the preceding claim, characterized in that the biocompatible materials are selected from latex, synthetic fibers, natural gums of the type chitosan, tamarind, alginate, gelatin, guar, xanthan gum, or mixtures of these gums, a polymer of the type polyacrylamide.

3. Membrane (1) according to the preceding claim, characterized in that it is made up of a mixture of chitosan and guar, or a mixture of chitosan and tamarind.

4. Membrane (1) according to any one of the preceding claims, characterized in that each band (8) has a specific tension within the membrane.

5. Membrane (1) according to any one of the preceding claims, characterized in that it is obtained by 3D printing.

6. Membrane (1) according to any one of the preceding claims, characterized in that it has an internal surface suitable for coming into contact with the muscle, said internal surface being functionalized.

7. A method for manufacturing a membrane (1) according to any one of claims 1 to 6, comprising the following steps: - scanning the muscle to be wrapped to define its external geometry and the orientation of its fibers; - modeling the geometry, elasticity, and directions extension of the membrane (1) to envelop at least partially the muscle; - formation of a support (2) taking the shape of the muscle; - formation of the membrane (1) from at least one biocompatible material to form the matrix (7) and the reinforcing bands (8).

8. Method according to the preceding claim, characterized in that the steps of forming the support (2) and the membrane (1) are carried out by 3D printing, the membrane (1) being printed simultaneously with the support (2).

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