Microstructured soft tissue grafts

Abstract

The present disclosure includes micropatterned fabrics, meshes, textiles, and implantable devices (300), which may include one substrate including a mesh (302), a second substrate having a microstructured surface (304), and a fibrous layer (308) disposed therebetween. The fibrous layer includes a plurality of randomly oriented fibers. The devices having a microstructured surface may include a plurality of first-level microfeatures and a plurality of second-level microfeatures, the plurality of second-level microfeatures being hierarchically arranged on the first-level microfeatures. Methods of manufacturing such micropatterned fabrics, meshes, textiles, and implantable devices are also disclosed.

Description

Technical Field

[0001] The present invention generally relates to micropatterned fabrics, meshes, and textiles, among others. More particularly, the present disclosure relates to devices of a substrate having micropatterns thereon, the substrate having the ability to generate an adhesive force to a target surface, and methods of manufacturing such devices.

Background Art

[0002] Implantable devices for repairing soft tissue defects generally have problems with movement. As a result, such devices, such as prostheses, are generally sutured or tacked to the tissue around the defect to limit the movement of the device from the target position. Mechanical means such as sutures or staples are efficient in limiting the movement of the device from the target position, but attaching the prosthesis to healthy tissue results in trauma to the tissue. The cascade of effects from this trauma can lead to postoperative adhesions, which can cause further complications and pain to the patient. The time required to place and attach the prosthesis significantly increases the time required to complete the procedure. Such prostheses generally do not have adhesive properties, and as a result, the prosthesis may move during the time interval between the initial placement of the prosthesis and its fixation to the tissue. Even more of a drawback, the lack of adhesive properties of these prostheses makes their implantation through minimally invasive procedures, such as laparoscopic procedures, particularly difficult, making them nearly unusable for such procedures.

[0003] What is needed, therefore, is a soft tissue repair device that has adhesive properties, can be fixed without the need for sutures or other mechanical means that cause trauma, and provides prevention of postoperative complications, such as adhesions or other trauma-related problems.

Summary of the Invention

[0004] In certain embodiments disclosed herein, an adhesive component may be added to the soft tissue repair fabric. In some embodiments, the soft tissue repair fabric may be a surgical mesh. The adhesive component may include a woven absorbent matrix applied to the mesh having fibers protruding from the surface of the mesh. The added fibers may significantly increase the mass and stiffness of the implantable fabric. In some embodiments, the implantable surgical mesh may generally rely on fibers to provide mesh strength. In certain embodiments, the fibers may also be decorated with adhesive microstructures that provide distinct clinical advantages compared to composite structures. Composite soft tissue repair fabrics include a first reinforcing component and a second anti-slip component. For example, one composite soft tissue repair fabric may be a sheet of adhesive microstructures bonded to a standard polypropylene mesh. The sheet component is often quite rigid, negating the flexible aspects of the woven mesh, making the tissue repair fabric stiffer and less flexible.

[0005] Consequently, there is a need for soft tissue repair fabrics that are well-fitting, strong, and contain minimal material weight.

[0006] There is also a need for soft tissue repair fabrics that self-adhere to the target tissue surface and are flexible enough to avoid the formation of gaps between the implantable fabric and the target tissue surface. The self-adhesion aspect of this disclosure may be described through capillary action or through the Wenzel-Cassie interface between the implantable fabric and the target tissue surface. This can be achieved through the establishment of [something].

[0007] There is a need for implants having a microsurface texture capable of generating immediate Wenzel-Cassie adhesion for implant fixation. In some embodiments, this same microsurface texture may further promote healthy integration of the implant with the surrounding tissue. Wenzel-Cassie adhesion may occur by the formation of a phase region at the interface between the implant surface and the tissue surface. This type of adhesion may form an interface layer between the tissue and the implant. Unexpectedly, the applicant has found that the formation of the Wenzel-Cassie zone of adhesion is stronger than that of a friction interface.

[0008] In some embodiments, the hierarchical structures disclosed herein may include multiscale configurations and assemblies having large and accessible surface compartments. Recent advances in nanomaterials science have increasingly enabled the design of hierarchical microstructured surfaces with unique properties. Much of this research has focused on hierarchical single-walled carbon nanotube films realized by simple, rapid, reproducible, and inexpensive filtration processes from aqueous dispersions. By varying the thickness of the carbon nanotube random network, it is possible to adapt their wettability due to capillary action in porous films.

[0009] In some embodiments, a hierarchically microstructured surface may be a surface microstructure that includes regions of higher surface energy juxtaposed with regions of lower surface energy. These high and low surface energy regions do not need to be stacked, but rather need to be juxtaposed with each other. Typically, stronger Wenzel-Cassie localization forces are achieved when the microstructure is stacked across three-dimensional space.

[0010] Microstructures with high surface energy are considered wettable, and if they are water-wettable, they are said to be hydrophilic. Microstructures with low energy are considered non-wettable, and if they are water-wettable, they are said to be hydrophobic. The combination of juxtaposed wettable and non-wettable zones creates what is known as the Wenzel-Cassie interface.

[0011] It will be understood that the Wenzel-Cassie interface does not require outward radial forces to generate localized forces. To translate the embeddable surface relative to the target surface, it is required to apply energy to disrupt the lower energy states of the Wenzel-Cassie interface. In some embodiments, the hierarchically microstructured surface has a small contact area with the target surface, and in some embodiments, there is no contact at all.

[0012] Certain embodiments of the present disclosure may include a microstructured surface having periodicity. This periodicity may generate a secondary Wenzel-Cassie interface, which is hereby referred to as a Wenzel-Cassie interface. The secondary Wenzel-Cassie interface is characterized as some type of mechanical deformation of the target surface and / or the microstructured surface that generates an interlocking state between the microstructured surface and the target surface, the deformation of which is caused by substantially non-frictional forces.

[0013] For example, in some embodiments, the target surface exhibits an intrinsic wrinkle mode of deformation that causes wrinkles on the target surface without mechanical damage occurring to the target surface. The microstructured surface may have e-mode(s). These wrinkles can be matched to one or more periodicities of the microstructured surface, so that the target surface and the microstructured surface interlock with minimal mechanical contact. Alternatively, the microstructured surface may also have intrinsic wrinkle modes that can achieve the same second-order Wenzel-Cassie effect. Essentially, shear forces may be converted into wrinkles on either the implantable surface or the tissue surface without displacement of the implant.

[0014] In some embodiments, related but distinct secondary Wenzel-Cassie effects may be associated with Schallamach waves. These waves are generated on either a microstructured surface or a target surface and contain multiple wrinkle components, some of which may not be eigenmodes. The periodicity of the microstructured surface may "catch" some components of the Schallamach waves and allow others to "pass by". This type of secondary Wenzel-Cassie interface is referred to herein as a "slip-grip" interface.

[0015] Other secondary and tertiary Wenzel-Cassie interfaces can also be used, in which case the Wenzel-Cassie interface and the periodicity of the microstructured surface work together to localize the implant placed on a dynamically changing target surface. The spatial periodicity of the microstructure may be coupled cooperatively with other mechanical properties of the microstructured surface, such as the Young's modulus of the material containing the microstructured surface. Additionally, the geometry of the microstructured surface and the method of attachment to the implant can enhance or reduce these secondary Wenzel-Cassie effects.

[0016] The soft tissue repair devices of the present invention may be characterized by mechanical properties different from any implants / prostheses currently disclosed in the prior art. Microstructured surfaces using hydrophobic and hydrophilic regions may result in devices that exhibit increased displacement force when the target contact surface / lumen is wet, when oil is applied, when a surfactant is applied, or when a lubricant is applied. This physical characteristic of enhanced grip under conditions that generally reduce grip is the opposite of the result found in implants / prostheses in the prior art where mechanical friction surface texture is generally present. The problem with implants / prostheses in the prior art is that the in vivo environment generally tends to lubricate the surface of the device and prevent frictional resistance to movement.

[0017] In order for prior art friction treatments, such as barbs, raised struts, surface cylinders, and cones, to be effective, a large radial force must be supplied to facilitate mutual penetration between the microstructure and the surface friction geometry. Conversely, in embodiments of the present disclosure, Wenzel-Cassie zones generated by the microstructure when wet can be prevented from moving through various non-contact effects broadly known as van der Waals forces. These localization forces can generally be characterized as electromechanical and quantum mechanical rather than mechanical and classical.

[0018] In some embodiments, the Wenzel-Cassie effect may generate a "suck-down" effect between the target surface and the implant device. Therefore, instead of an outward radial force being applied to the tissue, an inward (suck-down) radial force may be applied.

[0019] These novel effects are detailed in some aspects of the various embodiments of this disclosure, but in particular, in separate parts of the same device, one is preferred over the other in certain applications, Wenzel-C The combination of the Assie effect and the mechanical friction effect should not be excluded.

[0020] In some additional embodiments, adhesive and lubricating microsurface textures may be used in combination. Fluid thinning and fluid densification are common effects resulting from the disordering or ordering of water molecules, respectively, caused by the effect that the spatially distributed surface energy pattern of the microstructured surface has on electric dipoles in the interfacial fluid. In particular, regions of high surface energy may be juxtaposed with regions of low surface energy, thereby causing tissue dynamics to pass through the implant device without displacing it. These and other effects are described in detail below.

[0021] There is also a need for soft tissue repair fabrics that can be repositioned perioperatively without damaging the contact between the tissue and the prosthesis.

[0022] There is also a need for soft tissue repair fabrics with improved resistance to migration. In particular, there is a need for soft tissue repair fabrics that do not require sutures, temporary stitches, or other mechanical mechanisms between the fabric and the target surface to prevent postoperative device migration.

[0023] There is also a need for soft tissue repair fabrics that have the lowest surface density (mass per unit area) and the highest tensile strength.

[0024] Additionally, various methods for texturing or generating patterned effects in fabrics are generally known. These texturing methods include chemical methods, such as chemical etching and localized shrinkage techniques, and physical methods, such as mechanical cutting, compression, or compaction of the fabric area.

[0025] In some embodiments, the soft tissue repair fabric may include a mesh, an interfacial web structure, and an embossed microstructure. The microstructure may be embossed on a prepolymer layer on the interfacial web or may be embossed directly on the interfacial web by heating.

[0026] In a third embodiment, a standard polymer mesh may be internally heated to a deformable state and the microstructure is then embossed. The polymer mesh material is heated uniformly and non-destructively such that after the microstructure is embossed on the fibers constituting the mesh, the original tensile strength of the mesh is retained.

[0027] By means of the present disclosure, highly adhesive and hierarchically patterned effects are obtained in medical prostheses at relatively low processing costs.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 is an example of a method for generating an embodiment of the present disclosure. [Figure 2] FIG. 2 is a flowchart of a method for generating an embodiment of the present disclosure. [Figure 3] FIG. 3 is an example of one embodiment of a microstructured soft tissue device. [Figure 4] FIG. 4 is an example of a heating method for heating and embossing a microstructure on a soft tissue device. [Figure 5A] FIG. 5A is an example of one embodiment of a microstructured soft tissue device. [Figure 5B] FIG. 5B is an example of one embodiment of a microstructured soft tissue device; FIG. 5B is a detailed example of a grooved microstructure.

Modes for Carrying Out the Invention

[0029] Referring to Figure 2, a method for manufacturing a substrate on which a micropattern is arranged is disclosed. In some embodiments, the method may include providing a substrate. The substrate may include a material suitable for coating. In certain embodiments, the substrate may be a material of the type such as fabric, plastic, and polymer. In certain embodiments, the material may be biocompatible, bioabsorbable, biostable, or nonabsorbable, or a combination thereof. In some embodiments, the substrate may include at least one portion that is bioabsorbable and a second portion that is nonabsorbable. In other embodiments, the substrate may be biocompatible and may include one portion that is bioabsorbable and a second portion that is nonabsorbable. In certain embodiments, the substrate may include one or more combined materials, each component of which may be a fabric, plastic, or polymer, and may be biocompatible, bioabsorbable, biostable, or nonabsorbable, or a combination thereof.

[0030] In some embodiments, a polymer adhesive or binder coating may be applied to the substrate. The coated substrate may then be embossed. In certain embodiments, a mold or embossed surface may be applied to the coated substrate via a physical embossing structure, such as a cylindrical roller or stamping press. In some embodiments, the embossed coated substrate may be cured.

[0031] In some embodiments, the coating may be in a liquid state when undergoing the embossing process. In certain embodiments, the coating may be in a semi-liquid / semi-solid state when undergoing the embossing process. In certain embodiments where the coating is in a liquid state when undergoing embossing, the coating may be transported through a rotary cylindrical mold for embossing. In certain embodiments, the mold for the embossing process may be embossed in a cylindrical screen that can rotate simultaneously with the movement of the substrate beneath it.

[0032] Referring to Figure 1, a method for manufacturing a substrate with a micropattern may include a roller 102 of the substrate material. In some embodiments, the roller 102 may provide a continuous supply of the substrate material as it is unwound. The substrate material may be transferred to a second compartment where a coating may be applied. In some embodiments, the coating may be a polymer adhesive or binder. In certain embodiments, the coating may be applied via an immersion station 104. In other embodiments, the coating may be spray-applied or applied via electrostatic discharge. In some embodiments, after coating, the coated substrate may pass through a cylindrical embossing roller 106. In certain embodiments, the cylindrical embossing roller 106 may include a mold having a microstructured pattern that can be transferred to the coating. In some embodiments, the mold may be a positive mold. In some embodiments, the mold may be a negative mold. In some embodiments, the mold may include parts of both positive and negative molds. In certain embodiments, the embossing process may include a contact pressure cylinder 108 for applying pressure to the coated substrate in contact with the cylindrical embossing roller 106. In some embodiments, gas pressure may be applied instead of contact pressure cylinder 108.

[0033] In embodiments utilizing gas pressure, the gas is directed onto the surface of the mold to compress the mold. The coated substrate may be pressed, or the gas may be directed toward the coated substrate to press the coated substrate toward the mold.

[0034] After the coating has been embossed with a microstructured pattern, the microstructured substrate may be subjected to a curing treatment 110. The curing treatment may be one of the conventional types known in the art in which the coating solidifies or hardens. In some embodiments, the microstructured substrate may then be collected for storage or further processing. In some embodiments, the microstructured substrate may be wound onto a roll 112 of material.

[0035] In certain embodiments disclosed herein, coatings disposed on a substrate may generally be classified as aqueous and / or solvent-based coatings. In some embodiments, aqueous coatings may consist of one or more of the following: a binder, an emulsion polymer, and / or a viscosity enhancer, or any combination thereof. In certain embodiments, aqueous coatings may contain all of the binder, emulsion polymer, and viscosity enhancer. In other embodiments, they may also contain one or more of the following: a plasticizer, a thermosetting resin, a curing catalyst, a stabilizer, and / or other additives.

[0036] The emulsion polymer may be selected from the following: acrylic, vinyl-acrylic, vinyl, urethane and / or styrene-butadiene latex, and combinations thereof. In embodiments in which the coating is cured, it may generally be necessary to increase the viscosity of the coating to about 30,000 to 100,000 MPa-s (millipascal-seconds) immediately after embossing, thereby ensuring that the microstructure maintains the desired geometry between embossing and curing. In certain embodiments, viscosity may be governed at least in part by the properties of the substrate and / or by the way the microstructure is brought into contact with the coating layer.

[0037] Suitable thickeners for increasing viscosity may include water-soluble polymers such as carboxymethylcellulose, hydroxyethylcellulose, polyoxymethylene, and natural rubber, as well as alkali-swellable polymers such as highly carboxylated acrylic emulsion polymers and poloxamer prepolymers.

[0038] In some embodiments, plasticizers may be added to alter the feel of the finished article or to improve the flow and leveling characteristics of the coating. If one objective is to improve leveling characteristics, a temporary plasticizer, such as a phthalate, may be used. If one objective is to alter the feel of the finished device or at least a portion of the finished device, a more permanent plasticizer, such as a low molecular weight polyester, may be used.

[0039] In some embodiments, thermosetting resins, such as methylol-melamine, urea-formaldehyde condensate, or phenol-formaldehyde condensate, may be incorporated to improve the durability or wear resistance of the finished device.

[0040] In certain embodiments including a catalyst, oxalic acid or diammonium phosphate may be used. In some embodiments, the use of a catalyst may increase the rate of curing of the adhesive. More specialized additives may be used, which may include dyes or pigments for coloring the backing, e.g., urethane foam, UV absorber to be subjected to photodegradation, and the adhesive layer. If a breathable film is desired, the coating may be foamed chemically or mechanically. Solvent coatings are both fully reacted and The material may also contain soluble polymers, such as acrylic homopolymers and copolymers, polyesters, polyamides, or polyurethanes.

[0041] The solvent coating may also include both fully reacted soluble polymers, such as acrylic homopolymers and copolymers, polyesters, polyamides, or polyurethanes, as well as two subsets, such as polyester polyols with diisocyanates or isocyanate prepolymers and epoxy with polyamines.

[0042] The polymer or prepolymer may be dissolved in a suitable solvent, preferably one with low boiling properties, and then thickened to a suitable viscosity in a manner similar to that used for water-based adhesives. In some embodiments of the solvent-based coating, catalysts, crosslinkers, stabilizers, pigments, or dyes may also be incorporated.

[0043] Certain embodiments disclosed herein may incorporate a cylindrical die for embossing a pattern onto a substrate or a coating on a substrate. As previously disclosed, some embodiments may incorporate a contact pressure cylinder for applying pressure to a coated substrate in contact with a cylindrical embossing roller, while some embodiments may incorporate gas pressure instead of a contact pressure cylinder. In embodiments using gas pressure, the gas pressure may be in a range that provides acceptable results. In some embodiments, the gas pressure may be in the range of about 30 psi to about 100 psi. In certain embodiments, the gas pressure may be in the range of about 60 psi to 100 psi.

[0044] One embodiment of the cylindrical type may include a substrate or coated substrate that is present on and being transported on a conveyor belt or a similar transport system. In some embodiments, the conveyor belt may include positioning holders projecting upward from there for the purpose of maintaining the substrate in a substantially flat position relative to the belt, in addition to maintaining the placement of the substrate on the belt. Typically, the conveyor belt may be a tenter frame or a conventional type of conveyor belt or blanket, vacuum belt, etc., adapted to maintain the substrate in a flattened form. The conveyor may be wider than the substrate, and as a result, a boundary region may exist between the outer edge of the substrate and the outer edge of the belt on either side of the substrate. In some embodiments, the cylindrical type may be a rotary type that rotates at the same speed as, or approximately the same speed as, the conveyor system. In some embodiments, the conveyor system and the rotary type may include a wheel present on the boundary region of the belt. The wheel may be of any type of suitable material, such as plastic, metal, or rubber. The cylindrical type may include an extension projecting through the wheel and located on a support bracket adapted for rotatable support of the mold.

[0045] Therefore, thanks to the support bracket, the majority of the cylindrical mold's weight may be supported by the bracket. The wheel may then be lightly positioned on the boundary portion, and as a result, the conveyor's motion causes the cylindrical mold to rotate in the same direction as the substrate, while the axis of the cylindrical mold is maintained in a position substantially perpendicular to the direction of the conveyor's motion. In other embodiments, the cylindrical mold may include a support bracket that includes an integrated or external rotating device for rotating the cylindrical mold. The rotation of the cylindrical mold may be matched to the speed of the conveyor belt system.

[0046] Certain embodiments disclosed herein may include implantable devices for repairing soft tissue defects. In one embodiment, the device may include a surgical mesh having a laminate layer comprising a microstructure. In certain embodiments, the laminate-like structure may be positioned between two strong, abrasion-resistant surface regions relative to each other. It may also include a region having a soft, absorbent central core with a low fiber concentration.

[0047] Referring here to Figure 3, the embeddable device 300 may include a substrate having a mesh structure 302 and a microstructured surface 304. In some embodiments, the microstructured surface may include a region 306 having the ability to generate capillary action. In a particular embodiment, the capillary action region 306 may communicate with a fibrous layer 308 located between the microstructured surface 304 and the mesh surface 302. In a particular case, the capillary action may draw moisture into the fibers of the fibrous layer 308. The relatively low fiber concentration within the central core region 310 provides space for increasing the amount of moisture that can be absorbed by the fibrous layer.

[0048] In some embodiments, there is a network of fibers 312 within the central core region 310 that generally connects two surface regions without the use of a binder or adhesive. In some embodiments, a binder or adhesive may be used, but it does not have to be distributed throughout the entire central core region 310. In a particular embodiment, the binder in at least one surface region is distributed in a fine, gap-through pattern, and the bonded portions in that surface region are finely modeled to soften them. In other embodiments, the binder or adhesive may be used throughout the entire central core region. Generally, the binder or adhesive may be used to connect two surface regions in an embeddable device.

[0049] In certain embodiments disclosed herein, the formation of the fiber layer 308 may be achieved in a variety of ways. In some embodiments, it may be preferable to form a fiber layer 308 of randomly oriented short fibers 314, 316. In certain embodiments, the fiber layer 308 may include a first side portion 318 to which a first binder or adhesive that may permeate the fiber layer is applied. In some embodiments, permeation may occur through the thickness of the fiber layer for about 10 to about 60 microns, or about 10 to about 50 microns, about 10 to about 40 microns, about 10 to about 30 microns, about 10 to about 20 microns, or about 10 to about 15 microns. In other embodiments, permeation of the first binder may occur up to about 20 to about 50 microns, about 30 to about 40 microns, or about 35 microns. In further embodiments, transmission may occur at approximately 20 to 60 microns, 30 to 60 microns, 40 to 60 microns, or 50 to 60 microns.

[0050] In some embodiments, the fiber layer 308 may include a second side portion 320 on which a second binder material is applied in a fine, gap-through pattern, permeating through the thickness of the fiber layer at a distance of about 10 to about 60 microns, or about 10 to about 50 microns, about 10 to about 40 microns, about 10 to about 30 microns, about 10 to about 20 microns, or about 10 to about 15 microns. In other embodiments, 2 The permeation of the binding material may occur at a depth of approximately 20 to 50 microns, approximately 30 to 40 microns, or up to approximately 35 microns. In further embodiments, the permeation may occur at a depth of approximately 20 to 60 microns, approximately 30 to 60 microns, approximately 40 to 60 microns, or approximately 50 to 60 microns. In some embodiments, the first binding material and the second binding material are not in contact with each other in terms of the thickness of the fiber layer. In some embodiments, the first binding material and the second binding material are not substantially in contact with or connected to each other, and being substantially not in contact with or connected to each other includes a contact area of ​​less than 10%, less than 15%, less than 20%, less than 25%, less than 30%, less than 35%, less than 40%, less than 45%, or less than 50%.

[0051] In some embodiments, the implantable device may include applying a binding material to one side of a fiber layer in a fine, interspersed pattern so that the binding material adheres the first side of the fiber to a microstructured surface, and then repeating these steps for a second side of the fiber layer so that the second side is bonded to a surgical mesh.

[0052] In some embodiments in which a surgical mesh is used, the implantable device may include forming a fibrous layer, which may include randomly oriented short fibers 314, 316. In certain embodiments, the fibrous layer 308 may include a first side portion 318 to which a first binder or adhesive that may permeate the fibrous layer is applied. In some embodiments, permeation may occur through the thickness of the fibrous layer to about 10 to about 60 microns, or about 10 to about 50 microns, about 10 to about 40 microns, about 10 to about 30 microns, about 10 to about 20 microns, or about 10 to about 15 microns. In other embodiments, permeation of the first binder may occur to about 20 to about 50 microns, about 30 to about 40 microns, or up to about 35 microns. In further embodiments, transmission may occur at approximately 20 to 60 microns, 30 to 60 microns, 40 to 60 microns, or 50 to 60 microns.

[0053] In some embodiments, the fiber layer 308 may include a second side portion 320 on which a second binder material is applied in a fine, gap-through pattern, permeating through the thickness of the fiber layer at a distance of about 10 to about 60 microns, or about 10 to about 50 microns, about 10 to about 40 microns, about 10 to about 30 microns, about 10 to about 20 microns, or about 10 to about 15 microns. In other embodiments, 2The permeation of the binding material may occur at a depth of approximately 20 to 50 microns, approximately 30 to 40 microns, or up to approximately 35 microns. In further embodiments, permeation may occur at a depth of approximately 20 to 60 microns, approximately 30 to 60 microns, approximately 40 to 60 microns, or approximately 50 to 60 microns. In some embodiments, the first binding material and the second binding material are not in contact with each other at the thickness of the fiber layer. In some embodiments, the first binding material and the second binding material are not substantially in contact with or connected to each other, and being substantially not in contact with or connected to each other is less than 10%, less than 15%, less than 20%, less than 25%, less than 30%, less than 35%, less than 40%, or 45%. This includes less than 50% or less contact. In some embodiments, the second side portion 320 may then be bonded to the surgical mesh using a second bonding material. In some embodiments, the first side portion 318 may be bonded to a microstructured surface.

[0054] In some embodiments, the substrate may include a plurality of first-level microfeatures. The first-level microfeatures may have a height of 10 to 1,000 microns, a diameter of 10 to 1,000 microns, and a center-to-center pitch of 25 to 10,000 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of second-level microfeatures arranged hierarchically around the first-level microfeatures. In some embodiments, the second-level microfeatures may have a height of 5 to 200 microns, a diameter of 5 to 200 microns, and a center-to-center pitch of 10 to 1,000 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of third-level microfeatures arranged hierarchically around the second-level microfeatures. In some embodiments, the third-level microfeatures may have a height of 1 to 5 microns, a diameter of 5 to 200 microns, and a center-to-center pitch of 10 to 1,000 microns.

[0055] In some embodiments, the substrate may include a plurality of first-level microfeatures. The first-level microfeatures may have a height of 50 to 1000 microns, a diameter of 50 to 1000 microns, and a center-to-center pitch of 100 to 10,000 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of second-level microfeatures arranged hierarchically around the first-level microfeatures. In some embodiments, the second-level microfeatures may have a height of 10 to 200 microns, a diameter of 10 to 200 microns, and a center-to-center pitch of 50 to 1000 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of third-level microfeatures arranged hierarchically around the second-level microfeatures. In some embodiments, the third-level microfeatures may have a height of 1 to 5 microns, a diameter of 10 to 200 microns, and a center-to-center pitch of 100 to 1000 microns.

[0056] In some embodiments, the substrate may include a plurality of first-level microfeatures having a height of 100 to 750 microns, a diameter of 50 to 500 microns, and an inter-center pitch of 100 to 1000 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of second-level microfeatures arranged hierarchically around the first-level microfeatures, having a height of 25 to 100 microns, a diameter of 25 to 100 microns, and an inter-center pitch of 50 to 500 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of third-level microfeatures arranged hierarchically around the second-level microfeatures. In some embodiments, the third-level microfeatures may have a height of 1 to 5 microns, a diameter of 10 to 100 microns, and an inter-center pitch of 10 to 100 microns.

[0057] In some embodiments, the substrate may include a plurality of first-level microfeatures having a height of 100 to 500 microns, a diameter of 100 to 500 microns, and an inter-center pitch of 100 to 750 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of second-level microfeatures arranged hierarchically around the first-level microfeatures, having a height of 25 to 100 microns, a diameter of 25 to 100 microns, and an inter-center pitch of 50 to 500 microns between adjacent microfeatures. In some embodiments, the substrate may further include a plurality of third-level microfeatures arranged hierarchically around the second-level microfeatures. In some embodiments, the third-level microfeatures may have a height of 1 to 5 microns, a diameter of 10 to 100 microns, and an inter-center pitch of 10 to 100 microns.

[0058] In certain embodiments disclosed herein, the microstructured surface may be a microstructured pattern imprinted in a first binding material present on one side of a fiber layer. In some embodiments, the implantable device may involve applying the binding material to one side of a fiber layer in a fine, interstitial pattern and bonding a surgical mesh, with the microstructured pattern embossed on the opposite side of the fiber.

[0059] In some embodiments, each surface region may include a binder material. In certain embodiments, the binder material may be an elastomer. In certain embodiments, the elastomer binder material may be distributed throughout the fiber layer, or at least a portion thereof, to bind the fibers together to form a strong network and to provide abrasion resistance to both sides of the fiber layer. In some embodiments, one side may be formed or bonded to a mesh, and the other side may be formed or bonded to a microstructured surface. It may also be used.

[0060] In some embodiments, one side of the fiber layer having a binder material may be arranged in a fine, interstitial pattern, leaving a substantial portion of its surface without the binder material. In some embodiments, the substantial portion of the surface without the binder material may be at least 40 percent, more preferably 50 percent. In such embodiments with a substantial portion without the binder material, the fiber layer thus provides a highly absorbent compartment from which moisture can easily pass inside the fiber layer. In some embodiments, both sides of the fiber layer may contain a binder material arranged in a fine, interstitial pattern, leaving substantial portions of both sides of the fiber layer without the binder material. In some embodiments, the substantial portion of the surface without the binder material may be at least 40 percent, more preferably 50 percent. In such embodiments with a substantial portion without the binder material, the fiber layer thus provides a highly absorbent compartment from which moisture can easily pass inside the fiber layer.

[0061] In some embodiments disclosed herein, the central core region 310 may consist of a soft, relatively low-density network of fibers loosely held together by electrospinned bonds or deposited during electrospinning. In some embodiments, additional strength may be imparted to the central region by entanglement of relatively longer synthetic or natural fibers added to the fiber mixture of relatively shorter fibers disclosed above. The longer fibers may be provided such that the overall density of the fiber mixture is 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more of the shorter fibers. In some embodiments, the inclusion of relatively longer fibers may be the only strength imparted to the central region. To clarify, when referring to relatively longer fibers, longer fibers are defined as those that are at least 1.5 times the length of shorter fibers, or at least 2.0 times the length of shorter fibers, or at least 2.5 times the length of shorter fibers, or at least 3.0 times the length of shorter fibers, or at least 3.5 times the length of shorter fibers, or at least 4.0 times the length of shorter fibers, or at least 4.5 times the length of shorter fibers, or at least 5.0 times the length of shorter fibers, or at least 10.0 times the length of shorter fibers, or at least 20.0 times the length of shorter fibers, or at least 30.0 times the length of shorter fibers, or at least 4 times the length of shorter fibers. 0 This means that the length is 0.0 times that of the short fiber, or at least 50.0 times that of the short fiber, or at least 100.0 times that of the short fiber.

[0062] In some embodiments, the central core region may include separate compartments or portions containing cavities arranged along the entire core region. In some embodiments, these separate compartments or portions of cavities may provide additional features to the core region. For example, additional features may include greater bulk, softness, and absorbency to the fiber layer. In some embodiments, separating the separate compartments from one another may include a network of fibers connecting the microstructured surfaces and mesh together. This embodiment may enable the construction of an implantable device without using the undesirable rigid adhesives used in the prior art.

[0063] In some embodiments, the fiber layer may have a wavy appearance resulting from the patterning of the fiber layer through the use of a patterned coated binder. The controlled pattern of the fiber layer can increase its softness and compressibility, in addition to its bulk and absorbency.

[0064] Another embodiment of the present disclosure may include heating a surgical mesh and imprinting a microstructured pattern on the fibers of the surgical mesh. Heating the mesh fibers using a hot mandrel is unsatisfactory because the mandrel is too hot or too hot This is because prolonged application can degrade the tensile strength of the mesh. In extreme cases, excessively hot iron can melt the mesh or otherwise damage it, rendering it unusable for embedding or general use.

[0065] Therefore, one object of this disclosure is to provide an improved method and apparatus for continuously imprinting patterns on a material that are free from the defects and deficiencies described herein. In some embodiments, improved methods and apparatus are disclosed in which the heat used in softening the material and the duration for which it is applied can be appropriately controlled, and damage to the material is prevented.

[0066] According to certain embodiments of the present disclosure, a conveyor system or similar system capable of supplying a substrate between a cylindrical embossing roller and a pressure roller or gas pressure may further include one or more pairs of electrodes connected to a source of high-frequency electrical energy. Due to dielectric losses, the substrate, or portion of the substrate, may be heated uniformly rather than only superficially to the temperature required to imprint a microstructure onto the polymer layer. The application of slight pressure completes the microstructure transfer process from the mold to the fabric.

[0067] This method and apparatus allows the operator to maintain a degree of control far superior to that obtained by methods known in the prior art, namely convective heating, radiant heating, and / or contact heating.

[0068] Referring here to Figure 4, the substrate material 402 is supplied along a conveyor system or similar transport / production system between a pair of rotating circular electrodes 404, 406. In some embodiments, the pair or rotating circular electrodes 404, 406 may be powered by an RF supply source 408. The electrodes may be mechanically biased by a spring 410, which biases the electrodes toward each other, thereby exerting pressure on the substrate as the substrate passes between them.

[0069] The electrodes may be positioned near the point where the substrate enters the conveyor system, or as close as convenient to any other point where a manufacturing process is initiated. In some embodiments, there are two pairs of electrodes, each pair configured to receive one side of the substrate sheet being transported.

[0070] In one embodiment depicted in Figure 4, one of the pair of electrodes 404 may be rotated by a motor 412 connected via a reduction gear, a universal joint, and / or an insulating coupling. In some embodiments, the second electrode 406 of the pair may also be connected via an insulating coupling, a universal joint, and / or a reversing gear connected to the motor 412 via a transmission.

[0071] It will be understood that embodiments involving two electrodes must rotate in opposite directions. In some embodiments, the electrode system may further include thermally insulated belts 414, 416. The belts 414, 416 may act as driving means for supplying the material to be processed. However, in certain embodiments, the electrodes may be stationary or freely rotating, and other motor drive units may drive the substrate with respect to an electric field.

[0072] As further shown in Figure 4, each pair of electrodes may include an associated pair of belts 414, 416. In some embodiments, these belts may be made of Teflon® or other thermal insulating material. They may be held on idler rollers. Belts 414, 416 are attached to each of the electrodes 404, 406 of the substrate 402. The belt may be sandwiched between the surfaces. The belt may insulate the electrodes, so that the electrode temperature does not rise excessively when the substrate is heated. In some embodiments, if the belt is omitted, the electrodes will gradually become overheated due to contact with the heated substrate.

[0073] If the electrode temperature rises too high, the substrate may become sticky and adhere to the electrode in the absence of the belt. It is this surface transfer of heat that can cause damage to the polymer material and create a layer in the substrate that reduces its tensile strength.

[0074] To prevent the power applied through the belt from heating it, the belt may preferably be made from a material with very low dielectric loss. The material selected for the buffer layer may be a dielectric, such as PTFE, polypropylene, silicone, and / or polyamide. All of these materials have low dielectric loss, preventing them from heating in the RF field. These dielectrics also tend to have high dielectric breakdown voltage fluctuations.

[0075] A belt having contact with a uniformly heated substrate can be heated by such contact. If the belt is made relatively long and exposed so that the heat is not localized, the belt may begin to rapidly radiate such heat. If shorter belts are required due to spatial constraints, their radiation may be increased by directing airflow or other coolants onto the belt.

[0076] It should be understood that the belt may include any desired microstructure pattern that can be imprinted onto the heated target material. Due to uniform heating, the microstructure pattern is faithfully transferred in the absence of surface effects.

[0077] In some embodiments, the electrodes may be connected to an oscillator or another source of high-frequency electrical energy. While frequencies between 200 and 300 megahertz have proven practical for this application, operation is not limited to those frequencies. However, when such frequencies are used, it is possible to keep the voltage applied to the electrodes within favorable limits, thereby eliminating the possibility of voltage breakdown.

[0078] High-frequency electrical energy from the oscillator may establish an electric field between the electrodes. The substrate passing between the electrodes is heated uniformly and rapidly due to the dielectric loss of the material.

[0079] The following are examples of materials and patterns useful in carrying out the disclosures provided herein, but they are not intended to be limiting. [Examples]

[0080] Example 1. Microstructured surface Referring to Figure 5, a microstructured surface 500 is disclosed which may include a substrate 502. The substrate 502 may include a first sinusoidal microstructure 504, a second columnar microstructure 506 arranged on the sinusoidal microstructure, and a third grooved microstructure 508 arranged on the second columnar microstructure. Each of the three different microstructures is arranged hierarchically. The diameter, pitch, and height of each microstructure may be defined as follows. The dimensions of the first sinusoidal microstructure are 1.1 to 10 times the dimensions of the second columnar microstructure. The dimensions of the second columnar microstructure may be 1.1 to 10 times the dimensions of the third grooved microstructure. The second columnar microstructure may have any elliptical or polygonal cross-section.

[0081] Example 2. Mesh coated with microstructured prepolymer In certain embodiments, the microstructure may be crosslinked into a fixed shape or formed in a swellable polymer. Swellable microstructures may have the additional benefit of actively engaging with a target surface, such as tissue, as the microstructure swells.

[0082] Poloxamers and polylactic acid hydrogels Pluronic® 31R1 (molecular weight 3250) (BASF, Mt. Olive, NJ) was dried in a spherical flask under vacuum at 85°C for 12 hours. The final water content obtained was less than 300 ppm. One equivalent of Pluronic® 31R1 was added to 1 / 5 equivalent of (l)-lactide and 0.18 grams of catalyst (stannous 2-ethylhexanoate) (0.43%). The reaction was carried out in a sealed flask under a dry nitrogen saturated atmosphere at 145°C for 2.5 hours.

[0083] Two equivalents of toluene diisocyanate are added to the above compound, and the mixture is reacted at 60°C for 8 hours. Half an equivalent of a bifunctional molecule, such as Boswellia extract, is added to the resulting mixture, and the mixture is reacted at 75°C for 8 hours.

[0084] A hydrogel of the desired viscosity is formed by adding an appropriate amount of water. For example, 1 g of water may be added for a high-viscosity gel, or 100 g of water may be added for a low-viscosity gel.

[0085] The mesh coated with the above prepolymer can be cured in a high-humidity chamber, or it can be lightly sprayed with water.

[0086] Example 3. Polyethylene glycol and polylactic acid hydrogel Polyethylene glycol ("PEG") (molecular weight 3000) was dried overnight in a vacuum at 85°C. The PEG was then cooled to room temperature, and the product was capped with dry nitrogen. One equivalent of PEG was added to 1 / 5 equivalent of (1)-lactide and 0.18 grams of catalyst (stannous 2-ethylhexanoate). The mixture of PEG and lactide was placed in an oil bath under flowing nitrogen at 140°C and mixed for 3 hours.

[0087] Two equivalents of toluene diisocyanate are added to the above compound, and the mixture is reacted at 60°C for 8 hours. Half an equivalent of a bifunctional molecule, such as Boswellia extract, is added to the resulting mixture, and the mixture is reacted at 75°C for 8 hours.

[0088] A hydrogel of the desired viscosity is formed by adding an appropriate amount of water. For example, 1 g of water may be added for a high-viscosity gel, or 100 g of water may be added for a low-viscosity gel.

[0089] Example 4 Poloxamer and polylactic acid-based curable hydrogels Two moles of diisocyanate were provided under nitrogen in a reactor equipped with a stirring bar. The reactor may be heated to 60°C, and one mole of poloxamergol was slowly added. The poloxamer should be added at a rate slow enough so that the volume temperature does not rise above 65°C. If the poloxamer is solid at 60°C, a solvent can be used. Once all the poloxamer has been added to the reaction volume, the mixture should be reacted until the isocyanate content corresponds to two available NCO groups per poloxamer molecule. Slowly adding the poloxamer ensures that each poloxamer molecule is end-capped with two diisocyanate molecules, because the majority of the reaction is due to excess diisocyanate. This is because the reaction is carried out in an anneal, making chain elongation of poloxamer less likely. If preventing chain elongation is important, a large excess of diisocyanate can be used, and the excess diisocyanate is evaporated at the end of the reaction.

[0090] Once the poloxamer isocyanate is prepared as described above, 1 mole can be placed in a reactor under nitrogen and heated to 85°C, and 2 moles or more of dilactide (A) or more generally the ester can be slowly added to prevent excessive heat generation as described above.

[0091] To this result, half an equivalent of a bifunctional molecule, such as Boswellia extract, is added and the mixture is reacted at 75°C for 8 hours.

[0092] A hydrogel of the desired viscosity is formed by adding an appropriate amount of water. For example, add 1 g of water for a high-viscosity gel, or 100 g of water for a low-viscosity gel.

[0093] Having described certain embodiments of the present invention for novel and useful microstructured soft tissue grafts, such references are not intended to be construed as limitations on the scope of the invention, except as described in the following claims.

Claims

1. An implantable device for repairing soft tissue, A first substrate including a mesh; A second substrate having a microstructured surface; and The material includes a fiber layer containing a plurality of randomly oriented fibers, disposed between the first substrate and the second substrate. The microstructured surface comprises a plurality of first-level microfeatures and a plurality of second-level microfeatures, wherein at least a portion of the plurality of second-level microfeatures is arranged hierarchically on at least a portion of the first-level microfeatures. The plurality of first-level microfeatures have a height of 10 to 1,000 microns, a diameter of 10 to 1,000 microns, and a center-to-center pitch of 25 to 10,000 microns between adjacent microfeatures. The microstructured surface has a microstructure capable of generating Wenzel-Cassie adhesion for fixing an embeddable device to a target surface, Each microfeature on the surface of the second substrate is columnar, The second substrate is bioabsorbable, and the first substrate is nonabsorbable, and the mesh of the first substrate contains polypropylene. An implantable device.

2. The embeddable device according to claim 1, wherein the plurality of second-level microfeatures have a height of 5 to 200 microns, a diameter of 5 to 200 microns, and a center-to-center pitch of 10 to 1000 microns between adjacent microfeatures.

3. The embeddable device according to claim 1, wherein the plurality of first-level microfeatures include a sinusoidal waveform.

4. The embeddable device according to claim 1, wherein the microstructured surface further comprises a plurality of third-level microfeatures, and at least a portion of the plurality of third-level microfeatures is arranged hierarchically on at least a portion of the second-level microfeatures.

5. The embeddable device according to claim 4, wherein the plurality of third-level microfeatures include a height of 1 to 5 microns, a diameter of 5 to 200 microns, and a center-to-center pitch of 10 to 1000 microns.

6. The embeddable device according to claim 1, wherein a first binding material is disposed between the fiber layer and the first substrate, and a second binding material is disposed between the fiber layer and the second substrate, and the first and second binding materials are bonded together such that the first substrate and the second substrate are joined together via the fiber layer.

7. A fiber layer comprising a plurality of fibers, wherein the fiber layer comprises a first side and an opposing second side, The second substrate having the microstructured surface is configured such that the first side of the fiber layer has a first polymer coated on the first side, the first polymer permeates the fiber layer by 10 to 60 microns, and the first polymer further includes a microstructured pattern having the ability to generate Wenzel-Cassie adhesion for fixing an embeddable device to a target surface. The implantable device according to claim 1.

8. The embeddable device according to claim 7, wherein the binding material is disposed around the opposing second side portion of the fiber layer, the binding material is in contact with the mesh substrate, and the mesh substrate is bonded to the fiber layer.

9. The embeddable device according to claim 8, wherein the bonding material is permeable to the fiber layer in a range of 10 to 60 microns.

10. The embeddable device according to claim 9, wherein the first polymer and the binding material are not in contact with each other within the fiber layer.

11. The embeddable device according to claim 7, wherein the fiber layer comprises a plurality of randomly oriented shorter fibers deposited by electrospinning.

12. The embeddable device according to claim 7, wherein the fiber layer comprises a plurality of randomly oriented shorter fibers and a plurality of longer fibers, the longer fibers being at least 2.0 times longer than the plurality of shorter fibers, and the longer fibers constituting at least 50% of the overall density of the fiber layer.

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