Cross-Reference to Related Application(s)

[0001] This application claims the benefit of U.S. Provisional Application No. 63/145,278, filed February 03, 2021, which is incorporated herein by reference in its entirety.

Field of the Disclosure

[0002] The field of the present disclosure pertains to laminated collagen materials and processes for their production. More specifically, the present disclosure pertains to laminated collagen materials having blood absorbing and hemostatic properties.

Background of the Disclosure

[0003] Collagen is the main structural protein found in the connective tissues of the body. Medically, collagen is used to promote tissue growth, for reconstruction of bone and tissue, for wound healing, and for other surgical and reconstructive purposes.

[0004] For example, US Patent 6,977,231 describes a suturable adhesion-preventing membrane composed of at least one non-woven fabric layer made of collagen fibers, or a laminated membranous substance consisting of at least one non-woven fabric layer made of collagen fibers and at least one sponge layer made of collagen, and a coating layer of gelatin or hyaluronic acid on the surface or surfaces of the membrane. According to US Patent 6,977,231, the membrane described therein may be sutured, is biocompatible, has an adhesion-preventing effect, and promotes tissue regeneration.

[0005] US Patent 7,084,082 describes a collagen material having physical properties that allow suturing. The collagen material is characterized by filling or having inside a substance having biocompatibility that can be degraded and absorbed in the body into a matrix of a non-woven fabric-like multi-element structure of collagen fibers having ultra-fine fibers of collagen as its basic unit. According to US Patent 7,084,082, the collagen material may be used in a medical material such as an artificial tube for nerve, an artificial tube for spinal cord, an artificial esophagus, an artificial trachea, an artificial blood vessel, an artificial valve or alternative medical membranes such as an artificial endocranium, artificial ligamenta, artificial tendons, surgical sutures, surgical prostheses, surgical reinforcement, wound protecting materials, artificial skin and an artificial cornea.

[0006] US Patent 9,162,006 describes a hemostatic porous sponge comprising a matrix of a fibrous biomaterial (such as collagen, a protein, a biopolymer, or a polysaccharide) and particles of a fluid absorbing, particulate material adhered to the matrix material. According to US Patent 9,162,006, the sponge described therein has hemostatic properties.

[0007] There is a need for an inexpensive, mass -producible new laminated collagen material, particularly one having blood absorbing and hemostatic properties.

Summary of the Disclosure

[0008] Non-limiting illustrative examples of embodiments of the present disclosure will now be described in the following numbered clauses:

[0009] Clause 1: A laminated collagen material comprising: a first set of one or more nonwoven contiguous layers of compressed fibrillar collagen filaments, wherein the fibrillar collagen filaments comprise bundles of compressed collagen fibers; a sheet of a compressed gelatin sponge, wherein the gelatin sponge comprises a matrix of gelatin and spaces within the matrix of gelatin; and a first transition zone formed between the one or more non-woven contiguous layers and the sheet, wherein within the first transition zone, some bundles of the compressed collagen fibers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the first transition zone.

[0010] Clause 2: The laminated collagen material of clause 1, wherein the one or more nonwoven contiguous layers of compressed fibrillar collagen filaments comprise two layers. [0011] Clause 3: The laminated collagen material of clause 1, wherein the one or more nonwoven contiguous layers of compressed fibrillar collagen filaments comprise three layers.

[0012] Clause 4: The laminated collagen material of clause 1, wherein the one or more nonwoven contiguous layers of compressed fibrillar collagen filaments comprise four layers.

[0013] Clause 5: The laminated collagen material of any one of the preceding clauses, wherein the mean diameter of the compressed collagen fibers is from about 0.5 pm to about 10.0 pm.

[0014] Clause 6: The laminated collagen material of any one of the preceding clauses, wherein the thickness of the first set of one or more non-woven contiguous layers is from about 150 pm to about 250 pm, and the thickness of the sheet is from about 350 pm to about 400 pm.

[0015] Clause 7: The laminated collagen material of any one of the preceding clauses, wherein the density of the laminated collagen material is about 155.8 g/cm ³ .

[0016] Clause 8: The laminated collagen material of any one of the preceding clauses, further comprising: a second set of one or more non-woven contiguous layers of compressed fibrillar collagen filaments, wherein the fibrillar collagen filaments comprise bundles of compressed collagen fibers, and wherein the second set of one or more non-woven contiguous layers is disposed on the opposite side of the sheet than the first set of one or more non-woven contiguous layers; and a second transition zone formed between the second set of one or more non-woven contiguous layers and the sheet, wherein within the second transition zone, some bundles of compressed collagen fibers from the second set of one or more non-woven contiguous layers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the second transition zone.

[0017] Clause 9: The laminated collagen material of clause 8, wherein the second set of one or more non-woven contiguous layers of compressed fibrillar collagen filaments comprises two layers.

[0018] Clause 10: The laminated collagen material of clause 8, wherein the second set of one or more non-woven contiguous layers of compressed fibrillar collagen filaments comprises three layers. [0019] Clause 11: The laminated collagen material of clause 8, wherein the second set of one or more non-woven contiguous layers of compressed fibrillar collagen filaments comprises four layers.

[0020] Clause 12: The laminated collagen material of any one of clauses 8-11, wherein the mean diameter of the compressed collagen fibers of the first and second sets is from about 0.4 pm to about 8.0 pm.

[0021] Clause 13: The laminated collagen material of any one of clauses 8-12, wherein the thickness of the first set of one or more non-woven contiguous layers is from about 70 pm to about 100 pm, the thickness of the second set of one or more non-woven contiguous layers is from about 70 pm to about 100 pm, and the thickness of the sheet is from about 150 pm to about 200 pm.

[0022] Clause 14: The laminated collagen material of any one of the preceding clauses, wherein the fibrillar collagen filaments of the first set and the second set comprise residual amounts of sodium chloride.

[0023] Clause 15: The laminated collagen material of any one of the preceding clauses, wherein the fibrillar collagen filaments of the first set and the second set are salt-cured fibrillary collagen filaments.

[0024] Clause 16: The laminated collagen material of any one of the preceding clauses, wherein the one or more non-woven contiguous layers of the first set are layered along the same axis.

[0025] Clause 17: The laminated collagen material of any one of the preceding clauses, wherein the one or more non-woven contiguous layers of the second set are layered along the same axis.

[0026] Clause 18: The laminated collagen material of any one of clauses 1-15 or 17, wherein the one or more non-woven contiguous layers of the first set are layered along one or more axes. [0027] Clause 19: The laminated collagen material of any one of clauses 1-16 or 18, wherein the one or more non-woven contiguous layers of the second set are layered along one or more axes.

[0028] Clause 20: The laminated collagen material of any one of the preceding clauses, wherein the laminated collagen material is porous so as to absorb blood and promote hemostasis when in contact with blood.

[0029] Clause 21: The laminated collagen material of any one of clauses 8-20, wherein the density of the laminated collagen material is about 196.7 g/cm ³ .

[0030] Clause 22: The laminated collagen material of any one of the preceding clauses, wherein the mean length of the compressed fibrillar collagen filaments of the first set or the second set is from about 20 mm to about 150 mm.

[0031] Clause 23: The laminated collagen material of any one of the preceding clauses, wherein the mean length of the compressed collagen fibers of the first set or the second set is from about 5 mm to about 15 mm.

[0032] Clause 24: A process for producing a laminated collagen material, the process comprising the following steps: providing a first set of one or more non-woven contiguous layers of fibrillar collagen filaments, wherein the fibrillar collagen filaments comprise bundles of collagen fibers, wherein mean diameter of the bundles is from about 20 pm to about 300 pm, and mean diameter of the collagen fibers is from about 100 nm to about 300 nm; providing a sheet of a gelatin sponge adjacent to the first set of one or more non-woven contiguous layers, wherein the gelatin sponge comprises a matrix of gelatin and spaces within the matrix of gelatin; and compressing the first set of one or more non-woven contiguous layers and the sheet together to form a first transition zone between the one or more non-woven contiguous layers and the sheet of the laminated collagen material; wherein within the first transition zone formed by compression, some bundles of compressed collagen fibers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the first transition zone. [0033] Clause 25: The process of clause 24, further comprising: prior to compressing the first set of one or more non-woven contiguous layers and the sheet together, providing a second set of one or more non-woven contiguous layers of fibrillar collagen filaments, wherein the fibrillar collagen filaments comprise bundles of collagen fibers, wherein the mean diameter of the bundles in the second set is from about 20 pm to about 300 pm, the mean diameter of the collagen fibers in the second set is from about 100 nm to about 300 nm, and wherein the second set of one or more non-woven contiguous layers is disposed on the opposite side of the sheet than the first set of one or more non-woven contiguous layers; and when compressing the first set of one or more non-woven contiguous layers and the sheet, also compressing the second set of one or more non-woven contiguous layers together with the sheet to form the laminated collagen material; wherein the laminated collagen material further includes a second transition zone formed between the second set of one or more non-woven contiguous layers and the sheet, wherein within the second transition zone, some bundles of collagen fibers from the second set of one or more non-woven contiguous layers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the second transition zone.

[0034] Clause 26: The process of clause 24 or 25, wherein the mean length of the fibrillar collagen filaments of the first set or the second set is from about 20 mm to about 150 mm.

[0035] Clause 27: The process of any one of clauses 24, 25 or 26, wherein the mean length of the collagen fibers of the first set or the second set is from about 5 mm to about 15 mm.

[0036] Clause 28: A laminated collagen material produced by the process of any one of clauses 24-27.

[0037] Various other non-limiting embodiments of the present disclosure are also disclosed herein.

Brief Description of the Drawings

[0038] Figure 1A shows components used to produce a laminated collagen material in accordance with a non-limiting illustrative inventive embodiment of the present disclosure. [0039] Figure IB shows components used to produce a laminated collagen material in accordance with another non-limiting illustrative inventive embodiment of the present disclosure.

[0040] Figure 2 shows a laminated collagen material in accordance with a non-limiting illustrative inventive embodiment of the present disclosure.

[0041] Figure 3 shows a laminated collagen material in accordance with another non-limiting illustrative inventive embodiment of the present disclosure.

[0042] Figure 4 shows a scanning electron microscope (SEM) image (at 50x magnification) of a non-woven layer of fibrillar collagen filaments.

[0043] Figure 5 shows an SEM image (at 10,000x magnification) of a non-woven layer of fibrillar collagen filaments.

[0044] Figure 6 shows an SEM image (at 50x magnification) of a cross-section of two nonwoven layers of fibrillar collagen filaments.

[0045] Figure 7 shows an SEM image (at 200x magnification) of a cross-section of a nonwoven layer of fibrillar collagen filaments.

[0046] Figure 8 shows an SEM image (at 20x magnification) of a laminated collagen material in accordance with a non-limiting illustrative inventive embodiment of the present disclosure.

[0047] Figure 9 shows an SEM image (at l,000x magnification) of the laminated collagen material shown in Figure 8.

[0048] Figure 10 shows an SEM image (at 20x magnification) of the laminated collagen material shown in Figure 8.

[0049] Figure 11 shows an SEM image (at l,000x magnification) of the laminated collagen material shown in Figure 8.

[0050] Figure 12 shows an SEM image (at lOOx magnification) of a cross-section of the laminated collagen material shown in Figure 8. [0051] Figure 13 shows an SEM image (at 500x magnification) of a cross-section of the laminated collagen material shown in Figure 8.

[0052] Figure 14 shows an SEM image (at 20x magnification) of a laminated collagen material in accordance with another non-limiting illustrative inventive embodiment of the present disclosure.

[0053] Figure 15 shows an SEM image (at 10,000x magnification) of the laminated collagen material shown in Figure 14.

[0054] Figure 16 shows an SEM image (at 20x magnification) of the laminated collagen material shown in Figure 14.

[0055] Figure 17 shows an SEM image (at l,000x magnification) of the laminated collagen material shown in Figure 14.

[0056] Figure 18 shows an SEM image (at 500x magnification) of a cross-section of the laminated collagen material shown in Figure 14.

[0057] Figure 19 shows an SEM image (at lOOx magnification) of a cross-section of the laminated collagen material shown in Figure 14.

[0058] Figure 20 shows a stress-strain curve for the laminated collagen material shown in Figure 2 and the laminated collagen material shown in Figure 3.

Detailed Description of Illustrative, Non-limiting Inventive Embodiments

[0059] Various illustrative, non-limiting embodiments of this disclosure are described as follows with reference to the drawings, in which like parts are designated with like character references. Various ranges for parameters are disclosed in this application, with end points having approximate values. For this application, when the term “about” is used to modify a value, the term “about” means within + 10% of the value, unless otherwise specified. [0060] Any type of collagen fibers can compose the bundles used to produce the laminated collagen material of the present disclosure. Preferably, the collagen fibers are not lyophilized, thereby leading to less denaturing of the collagen, and longer collagen fibers. An example of a preferred process for producing the collagen fibers includes using bovine tendons as the collagen source, washing the tendons, treating them with sodium hydroxide, treating them with hydrochloric acid, compressing the tendons, treating them with sodium chloride, and dehydrating via acetone treatment. This preferred process of producing the collagen fibers is described in detail in US Patent No. 4,404,033, which is incorporated herein by reference in its entirety. Collagen fibers produced by this preferred process may include residual amounts of sodium chloride. In addition, collagen fibers produced by this preferred process may be salt-cured collagen fibers.

[0061] The collagen fibers are then processed by conventional textile equipment into a nonwoven layer of fibrillar collagen filaments, wherein the fibrillar collagen filaments comprise bundles of the collagen fibers. For example, collagen fibers can be processed by a carding machine with layering attachments to produce one or more non-woven layers of fibrillar collagen filaments. In some embodiments of the present disclosure, the one or more non-woven contiguous layers of fibrillar collagen filaments are layered along the same axis. In some embodiments of the present disclosure having more than one non-woven contiguous layer of fibrillar collagen filaments, the non-woven contiguous layers of fibrillar collagen filaments are layered along more than one axis.

[0062] In some embodiments of the present disclosure, the fibrillar collagen filaments may include residual amounts of sodium chloride. In addition, in some embodiments of the present disclosure, the fibrillar collagen filaments may be salt-cured fibrillar collagen filaments.

[0063] Figure 1A shows the components used to produce an embodiment of the laminated collagen material of the present disclosure. In Figure 1A, there is a set (1) of two non-woven contiguous layers of fibrillar collagen filaments, and on top of these two non-woven contiguous layers are two individual sheets (2) of a gelatin sponge. The two sheets (2) shown are identical and are used to produce two samples of an embodiment of the laminated collagen material of the present disclosure. Although the set (1) in Figure 1A consists of two non-woven contiguous

0) layers of fibrillar collagen filaments, the set (1) may contain one or more non-woven contiguous layers of fibrillar collagen filaments as a component in producing an embodiment of the laminated collagen material of the present disclosure. For example, in some other embodiments, a set (1) of one, three or four non-woven contiguous layer(s) of fibrillar collagen filaments are used to produce an embodiment of the laminated collagen material of the present disclosure.

[0064] In each non-woven contiguous layer, the fibrillar collagen filaments comprise bundles of collagen fibers. Figure 4 shows an SEM image (at 50x magnification) of a non-woven layer of fibrillar collagen filaments. As seen in Figure 4, via visual inspection of the SEM image, there are bundles of collagen fibers having diameters, for example, of 27.4 pm and 207.8 pm. Nonlimiting examples of the bundles of collagen fibers of the present disclosure include those having a mean diameter in the range of about 20 pm to about 300 pm.

[0065] Figure 5 shows an SEM image (at 10,000x magnification) of a non-woven layer of fibrillar collagen filaments. As seen in Figure 5, via visual inspection of the SEM image, there are individual collagen fibers (which make up the bundles) having diameters, for example, of 96 nm, 158 nm and 169 nm. Non-limiting examples of the individual collagen fibers (which make up the bundles) of the present disclosure include those having a mean diameter in the range of about 100 nm to about 300 nm.

[0066] Figure 6 (at 50x magnification) and Figure 7 (at 200x magnification) show SEM images of a cross-section of two non-woven layers of fibrillar collagen filaments and one non-woven layer of fibrillar collagen filaments, respectively. As seen from these images in Figures 6 and 7, the structural characteristics of the non-woven layer of fibrillar collagen filaments in its crosssection is similar to the structural characteristics of the non-woven layer of fibrillar collagen filaments on its surface (as shown in Figures 4 and 5).

[0067] In the sheet (2) of a gelatin sponge (as shown in Figure 1A), the gelatin sponge comprises a matrix of gelatin and spaces within the matrix of gelatin. In some embodiments of this disclosure, the gelatin sponge comprises lyophilized hydrolyzed collagen. Non-limiting examples of the gelatin sponge include the Surgispon® sponge sold by Aegis Lifesciences. Additional types of gelatins and additional types of sponges may be used as the sheet (2) in some embodiments of the present disclosure. [0068] Figure IB shows the components used to produce another embodiment of the laminated collagen material of the present disclosure. In Figure IB, there is a second set (3) of two nonwoven contiguous layers of fibrillar collagen filaments, and this second set (3) is placed on top of a sheet (2) of a gelatin sponge (not shown), which is placed on top of a first set (1) of two nonwoven contiguous layers of fibrillar collagen filaments (not shown). The sheet (2) and the first set (1) of two non-woven contiguous layers are not shown in Figure IB because they are covered up by the second set (3) of two non-woven contiguous layers. Thus, in this embodiment as shown in Figure IB, the sheet (2) of a gelatin sponge is sandwiched between the first set (1) of two non-woven contiguous layers (on the bottom) and the second set (3) of two non-woven contiguous layers (on the top). Although the second set (3) in Figure IB consists of two nonwoven contiguous layers of fibrillar collagen filaments, the second set (3) may alternatively contain one or more non-woven contiguous layers of fibrillar collagen filaments as a component in producing an embodiment of the laminated collagen material of the present disclosure. For example, in some other embodiments, a second set (3) of one, three or four non-woven contiguous layer(s) of fibrillar collagen filaments is used to produce an embodiment of the laminated collagen material of the present disclosure.

[0069] In some embodiments of the present disclosure, the laminated collagen material is sufficiently porous so as to absorb blood and promote hemostasis when in contact with blood.

Examples

[0070] The components as shown in Figures 1A and IB can be used to produce embodiments of the laminated collagen material of the present disclosure.

Example 1A

[0071] For example, with reference to Figure 1A, the set (1) of two non-woven contiguous layers of fibrillar collagen filaments is positioned on paper (6), and a sheet (2) of the gelatin sponge is placed on top of and adjacent to the set (1) of two non-woven contiguous layers of fibrillar collagen filaments. Next, the set (1) of two non-woven contiguous layers and a sheet (2) are compressed together to form an embodiment of the laminated collagen material. The compression may be done via any type of compression machine, such as a calender machine (i.e., a compression roller). In this example, the set (1) of two non-woven contiguous layers and the adjacent sheet (2) were fed through the rollers of a 2-Bowl Ramisch Kleinewefers Calender (type: RKK 210 P), with the pressure set to 15 kN using the pressure regulator. The embodiment of the laminated collagen material (4) as formed by this process is shown in Figure 2. The density of the laminated collagen material (4) shown in Figure 2 is about 155.8 g/cm ³ after compression by this calendar machine. As shown in Figure 2, the external surface of the compressed gelatin sponge layer (2) of the laminated collagen material (4) is pocked with regular pitlike depressions resulting from the fact that the pressing surface of the calendar machine has regular protrusions that help prevent the material (4) from slipping out of the calendar machine during compression.

[0072] Figures 8 and 9 show SEM images (at 20x magnification and l,000x magnification, respectively) of the embodiment of the laminated collagen material (4) shown in Figure 2, viewing the side of the set (1) of two non-woven contiguous layers of fibrillar collagen filaments. As seen in Figure 9, via visual inspection of the SEM image, there are compressed collagen fibers having diameters, for example, of 633 nm, 1.1 pm, 1.8 pm, 3.0 pm and 9.4 pm. Nonlimiting examples of the compressed collagen fibers include those having a mean diameter in the range of about 0.5 pm to about 10.0 pm.

[0073] Figures 10 and 11 show SEM images (at 20x magnification and l,000x magnification, respectively) of the embodiment of the laminated collagen material (4) shown in Figure 2, viewing the side of the sheet (2) of the gelatin sponge. As seen in Figure 11, via visual inspection of the SEM image, the gelatin sponge comprises a matrix of gelatin (110) and spaces (111) within the matrix of gelatin.

[0074] When the set (1) of two non-woven contiguous layers and the sheet (2) are compressed together to form the embodiment of the laminated collagen material (4) shown in Figure 2, they also form a first transition zone between the set (1) of two non-woven contiguous layers and the sheet (2). Within this first transition zone formed by compression, some bundles of compressed collagen fibers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the first transition zone.

[0075] Figures 12 and 13 show SEM images (at lOOx magnification and 500x magnification, respectively) of a cross-section of the embodiment of the laminated collagen material (4) shown in Figure 2. Figure 13 shows the first transition zone (130) formed by compression, wherein some bundles of compressed collagen fibers (131) protrude into the compressed gelatin sponge (132) so as to substantially fill those spaces within the matrix of gelatin (133) at the first transition zone. As seen in Figure 12, via visual inspection of the SEM image, the thickness of the set (121) of two non-woven contiguous layers of compressed fibrillar collagen filaments is about 199.4 pm, and the thickness of the sheet (132) of the compressed gelatin sponge is about 374.5 pm. Non-limiting examples of the set of one or more non-woven contiguous layers of compressed fibrillar collagen filaments include those having a thickness in the range of about 150 pm to about 250 pm, and non-limiting examples of the sheet of a compressed gelatin sponge include those having a thickness in the range of about 350 pm to about 400 pm. Non-limiting examples of the laminated collagen material include those having a total thickness in the range of about 400 pm to about 1,000 pm, about 500 pm to about 1,000 pm, or about 500 pm to about 650 pm.

Example IB

[0076] In this example, with reference to Figure IB, the second set (3) of two non-woven contiguous layers of fibrillar collagen filaments are placed on top of a sheet (2) of the gelatin sponge (not easily seen through the second set (3) of two non-woven contiguous layers of fibrillar collagen filaments), which is placed on top of a first set (1) of two non-woven contiguous layers of fibrillar collagen filaments (not viewable because it is covered by both the sheet (2) and the second set (3) of two non-woven contiguous layers of fibrillar collagen filaments). Thus, in this embodiment as shown in Figure IB, the sheet (2) of a gelatin sponge is sandwiched between the first set (1) of two non-woven contiguous layers (on the bottom) and the second set (3) of two non-woven contiguous layers (on the top). Next, the first set (1) of two non-woven contiguous layers, the sheet (2) and the second set (3) of two non-woven contiguous layers are compressed together (with the sheet (2) sandwiched between the first set (1) of two non-woven contiguous layers and the second set (3) of two non-woven contiguous layers) to form an embodiment of the laminated collagen material. The compression may be done via any type of compression machine, such as a calender machine (i.e., a compression roller). In this example, the first set (1) of two non-woven contiguous layers, the sheet (2) and the second set (3) of two non-woven contiguous layers were fed through the rollers of a 2-Bowl Ramisch Kleinewefers Calender (type: RKK 210 P), with the pressure set to 15 kN using the pressure regulator. The embodiment of the laminated collagen material (5) as formed by this process is shown in Figure 3. The density of the laminated collagen material (5) shown in Figure 3 is about 196.7 g/cm ³ after compression by this calendar machine. As shown in Figure 3, the external surface of the compressed gelatin sponge layer (2) of the laminated collagen material (5) is pocked with regular pitlike depressions resulting from the fact that the pressing surface of the calendar machine has regular protrusions that help prevent the material (5) from slipping out of the calendar machine during compression.

[0077] Figures 14 and 15 show SEM images (at 20x magnification and 10,000x magnification, respectively) of the embodiment of the laminated collagen material (5) shown in Figure 3, viewing the side of the first set (1) of two non-woven contiguous layers of compressed fibrillar collagen filaments. As seen in Figure 15, via visual inspection of the SEM image, there are compressed collagen fibers having diameters, for example, of 57 nm, 116 nm, 138 nm and 597 nm. Non-limiting examples of the compressed collagen fibers include those having a mean diameter in the range of about 50 nm to about 600 nm, about 50 nm to about 8.0 pm, or about 0.4 pm to about 8.0 pm.

[0078] Figures 16 and 17 show SEM images (at 20x magnification and l,000x magnification, respectively) of the embodiment of the laminated collagen material (5) shown in Figure 3, viewing the side of the second set (3) of two non-woven contiguous layers of compressed fibrillar collagen filaments. As seen in Figure 17, via visual inspection of the SEM image, there are compressed collagen fibers having diameters, for example, of 422 nm, 955 nm, 2.0 pm and 6.6 pm. Non-limiting examples of the compressed collagen fibers include those having a mean diameter in the range of about 0.4 pm to about 8.0 pm.

[0079] When the first set (1) of two non-woven contiguous layers, the sheet (2) of the gelatin sponge, and the second set (3) of two non-woven contiguous layers are compressed together to form the embodiment of the laminated collagen material (5) shown in Figure 3, they also form a first transition zone between the first set (1) of two non-woven contiguous layers and the sheet (2), and a second transition zone between the second set (3) of two non-woven contiguous layers and the sheet (2). Within the first transition zone formed by compression, some bundles of compressed collagen fibers from the first set of two non-woven contiguous layers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the first transition zone. Within the second transition zone formed by compression, some bundles of compressed collagen fibers from the second set of two non-woven contiguous layers protrude into the compressed gelatin sponge so as to substantially fill those spaces within the matrix of gelatin at the second transition zone.

[0080] Figures 18 and 19 show SEM images (at 500x magnification and lOOx magnification, respectively) of a cross-section of the embodiment of the laminated collagen material (5) shown in Figure 3. Figure 18 shows the second transition zone (180) formed by compression, wherein some bundles of compressed collagen fibers (181) protrude into the compressed gelatin sponge (182) so as to substantially fill those spaces within the matrix of gelatin (183) at the second transition zone. As seen in Figure 19, via visual inspection of the SEM image, the thickness of the first set (191) of two non-woven contiguous layers of compressed fibrillar collagen filaments is about 70 pm to about 100 pm, the thickness of the sheet (182) of the compressed gelatin sponge is about 150 pm to about 200 pm, and the thickness of the second set (192) of two nonwoven contiguous layers of compressed fibrillar collagen filaments is about 70 pm to about 100 pm. Non-limiting examples of the laminated collagen material include those having a total thickness in the range of about 290 pm to about 1,000 pm, about 290 pm to about 400 pm, or about 400 pm to about 1,000 pm.

[0081] Figure 20 shows a stress-strain diagram obtained by dynamic mechanical analysis (DMA), with a controlled force test method. The DMA testing was done in accordance with ASTM D7028, using a Q800 DMA from TA Instruments. In Figure 20, the vertical axis corresponds to stress (MPa), and the horizontal axis corresponds to strain (%). The two curves 201 denote two samples from the laminated collagen material (4) shown in Figure 2 and produced in Example 1A, and the two curves 202 denote two samples from the laminated collagen material (5) shown in Figure 3 and produced in Example IB. As seen from this stressstrain diagram, the laminated collagen material (5) shown in Figure 3 and produced in Example IB is substantially stronger and more elastic than the laminated collagen material (4) shown in Figure 2 and produced in Example 1A. Specifically, when a maximum stress is applied to the laminated collagen materials, the laminated collagen materials (5) shown in Figure 3 and produced in Example IB (denoted by curves 202) exhibit up to about 5% to about 5.75% deformation before breaking, while the laminated collagen materials (4) shown in Figure 2 and produced in Example 1A (denoted by curves 201) exhibit up to about 3.25% deformation before breaking. Thus, it appears that the addition of the second set of two non-woven contiguous layers of compressed fibrillar collagen filaments in Example IB serves to substantially increase strength and elasticity of the resulting laminated collagen material.

[0082] In the laminated collagen materials (4) and (5), the sheet of the compressed gelatin sponge provides resistance to any applied stress and makes the laminated collagen materials (4) and (5) more elastic and stronger as compared to non-woven contiguous layer(s) of compressed fibrillar collagen filaments by themselves, which are inelastic and easily breakable. When used alone as a hemostatic material, compressed fibrillar collagen filaments absorb blood and become wet, eventually turning into a gel that cannot hold sutures. This limits their usage and application as a hemostatic material. In contrast, the laminated collagen materials of the present disclosure provide the advantage of being more elastic and stronger than compressed fibrillar collagen filaments alone. This combination of increased elasticity and strength allows the laminated collagen material to be sutured and to retain its form and workability when wet with absorbed blood. Thus, when used as a hemostatic material, the laminated collagen materials of the present disclosure provide a clinical benefit over the usage of compressed fibrillar collagen filaments alone.

[0083] While the present disclosure provides multiple exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of this disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of this disclosure without departing from the essential scope thereof. Therefore, it is intended that the invention, as defined in the appended claims, not be limited to any particular embodiment disclosed herein, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item unless otherwise explicitly indicated.