Hydrophilic eptfe sheet and method for making eptfe sheet hydrophilic

Abstract

[Problem] To enhance the hydrophilicity of an ePTFE sheet and thereby provide a hydrophilic ePTFE sheet that can be used for applications such as implanting in a human body and attachment to the surface of an organ. [Solution] A hydrophilic ePTFE sheet 10 is formed from an ePTFE sheet 12, Japanese paper 14 laminated on the surface of the ePTFE sheet 12 after atmospheric pressure plasma treatment thereof, and a collagen layer 16 applied to the surface of the Japanese paper 14.

Description

Hydrophilized ePTFE sheet and method for hydrophilizing ePTFE sheet

[0001] The present invention relates to a highly biocompatible and hydrophilized ePTFE sheet, and a method for hydrophilizing a highly biocompatible ePTFE sheet.

[0002] Expandable PTFE (ePTFE [polytetrafluoroethylene]), which is inert, thin, lightweight, and highly durable, is used in various fields such as gland packings, gaskets, and architectural fabrics (see, for example, Patent Document 1).

[0003] Patent Application No. 2016-138188

[0004] However, ePTFE has the problem that it is difficult to bond to other different materials because it is hydrophobic.

[0005] In particular, it has been difficult to utilize the biocompatibility of ePTFE to be used in applications such as implanting it in the human body or attaching it to the surface of an organ or the like.

[0006] The present invention has been made in view of these problems, and its object is to provide a hydrophilized ePTFE sheet that can be used for applications such as implanting it in the human body or attaching it to the surface of an organ, etc., by increasing its hydrophilicity, and a method for hydrophilizing an ePTFE sheet.

[0007] According to one aspect of the present invention, there is provided a hydrophilized ePTFE sheet comprising: an ePTFE sheet; Japanese paper laminated on the surface of the ePTFE sheet that has been treated with atmospheric pressure plasma; and a collagen layer applied to the surface of the Japanese paper.

[0008] Preferably, the surface of the collagen layer is irradiated with an ion beam.

[0009] According to another aspect of the present invention, there is provided a method for hydrophilizing an ePTFE sheet, comprising: treating the surface of an ePTFE sheet with atmospheric pressure plasma; laminating Japanese paper on the atmospheric pressure plasma-treated surface; and applying a collagen layer to the surface of the Japanese paper.

[0010] Preferably, the surface of the collagen layer is irradiated with an ion beam.

[0011] The hydrophilic ePTFE sheet of the present invention is prepared by laminating Japanese paper on an ePTFE sheet whose surface has been treated with atmospheric pressure plasma, and then applying a collagen layer to the surface of the Japanese paper. This makes it possible to provide ePTFE with an enhanced hydrophilic surface.

[0012] Fig. 1 is a diagram showing an example of a hydrophilic ePTFE sheet 10 according to an embodiment; Fig. 2 is a diagram showing a manufacturing process of the hydrophilic ePTFE sheet 10; Fig. 3 is a diagram explaining a contact angle; Fig. 4 is a diagram showing an example of the principle of electron beam irradiation; Fig. 5 is a diagram showing an example of ion beam irradiation; Fig. 6 is a diagram showing an example of the principle of electron beam irradiation; Fig. 7 is a diagram showing an example of the principle of ion beam irradiation; Fig. 8 is a diagram showing an example of the principle of electron beam irradiation; Fig. 9 is a diagram showing an example of the principle of ion beam irradiation; Fig. 10 is a diagram showing an example of the principle of electron beam irradiation; Fig. 11 is a diagram showing an example of the principle of electron beam irradiation; Fig. 12 is a diagram showing an example of the principle of ion beam irradiation; Fig. 13 is a diagram showing an example of the principle of electron beam irradiation; Fig. 14 is a diagram showing an example of the principle of ion beam irradiation; Fig. 15 is a diagram showing an example of the principle of electron beam irradiation; Fig. 16 is a diagram showing an example of the principle of ion beam irradiation; Fig. 17 is a diagram showing an example of the principle of electron beam irradiation; Fig. 18 is a diagram showing an example of the principle of electron beam irradiation; Fig. 19 is a diagram showing an example of the principle of ion beam irradiation; Fig. 20 is a diagram showing an example of the principle of electron beam irradiation; Fig. 21 is a diagram showing an example of the principle of electron beam irradiation; Fig. 22 is a diagram showing an example of the principle of ion beam irradiation; Fig. 23 is a diagram showing an example of the principle of electron beam irradiation; Fig. 24 is a diagram showing an example of the principle of electron beam irradiation; Fig. 25 is a diagram showing an example of the principle of electron beam irradiation; Fig. 26 is a diagram showing an example of the principle of ion beam irradiation; Fig. 27 is a diagram showing an example

[0013] (Configuration of Hydrophilic ePTFE Sheet 10) As shown in FIG. 1, the hydrophilic ePTFE sheet 10 according to this embodiment generally comprises an ePTFE sheet 12, Japanese paper 14, and a collagen layer 16.

[0014] The ePTFE sheet 12 preferably has a thickness of 50 μm to 500 μm.

[0015] The surface of this ePTFE sheet 12 has been subjected to atmospheric pressure plasma treatment, as shown in Figure 2. Atmospheric pressure plasma treatment can change the hydrophobic ePTFE sheet 12 to a hydrophilic state, making it possible to laminate films, cellulose, etc., which would not normally adhere to the ePTFE sheet, onto the ePTFE sheet.

[0016] The washi paper 14 is a component laminated on the atmospheric plasma-treated surface of the ePTFE sheet 12. In this specification, it refers to a film-like material made by adding plant-derived cellulose fibers to an aqueous polysaccharide solution, stirring, and uniformly dispersing the fibers. It is preferable to use washi paper 14 with a thickness of 10 μm to 100 μm. Washi paper 14 is made from extremely fine cellulose fibers obtained from plant fibers, particularly the epidermis of paper mulberry, gampi, and mitsumata. The polysaccharides used for the suspension, such as those obtained from the taro plant, are sometimes used as food additives. Because no chemicals are used, it is non-irritating to living organisms and can be said to be a material with excellent biocompatibility.

[0017] One method for laminating the Japanese paper 14 onto the surface of the ePTFE sheet 12 is to heat the Japanese paper 14 to 100°C to 200°C, heat the ePTFE sheet 12 to 150°C to 200°C, and then pressurize the Japanese paper 14 onto the surface of the ePTFE sheet 12 at 0.2 MPa to 1.0 MPa (see Figure 3).

[0018] The collagen layer 16 is a layer of collagen solution applied to the surface of the Japanese paper 14. A specific example of the collagen solution is Type I "AteloCell (catalog number: IPC-50)" manufactured by Koken Co., Ltd. The thickness of the collagen layer 16 is preferably 10 μm to 40 μm.

[0019] To form the collagen layer 16, for example, the original collagen solution is diluted by at least two times with purified water, and the Japanese paper 14 laminated on the surface of the ePTFE sheet 12 is immersed in the diluted collagen solution to uniformly coat it. The ePTFE sheet 12 and Japanese paper 14 are then removed from the diluted collagen solution and air-dried. This process is repeated multiple times, after which the diluted collagen solution is completely dried. At this point, the hydrophilized ePTFE sheet 10 is completed, as shown in FIG. 1.

[0020] The contact angle of the completed hydrophilized ePTFE sheet 10 on the side where the collagen layer 16 is formed and on the opposite side are measured, and it is confirmed that the contact angle on the side where the collagen layer 16 is formed is 90° or less and the contact angle on the opposite side is 90° or more. The "contact angle" is an index used in wettability evaluation, and is a numerical representation of the degree of swelling of a droplet formed when a liquid is dropped onto a solid. Specifically, as shown in Figure 4, the liquid adhering to the top surface of the solid is observed from the side, and the angle θ of the liquid at the end point of the droplet is measured relative to the solid surface.

[0021] Furthermore, the amount of liquid absorbed is measured on the side where the collagen layer 16 is formed and on the opposite side of the hydrophilized ePTFE sheet 10. It is confirmed that the amount of liquid absorbed on the side where the collagen layer 16 is formed is 40% or less after 30 seconds has elapsed, and that the amount of liquid absorbed on the opposite side remains unchanged even after 30 seconds or more has elapsed.

[0022] (Variation 1) In the above-described embodiment, the hydrophilic ePTFE sheet 10 is completed by forming a collagen layer 16 on the surface of the Japanese paper 14, but the surface of this collagen layer 16 may also be irradiated with an ion beam, electromagnetic waves, or electron beams.

[0023] The principle of electron beam irradiation (thermionic type) can be briefly explained using Figure 5. When an electric current is passed through a tungsten filament placed in the center of a vacuum chamber, the filament is heated and emits thermoelectrons. The emitted thermoelectrons are first extracted by a grid. These thermoelectrons are then accelerated to nearly the speed of light by a high voltage (accelerating voltage) of 80 to 300 kV between the terminal and the anode window, becoming an electron stream. These electrons then pass through the thin foil (aluminum or titanium) of the window and are emitted into the outside world as an electron beam. This electron beam is used in electron beam irradiation.

[0024] An example of ion beam irradiation will be briefly described below. As shown in FIG. 6 , an ion beam irradiation device 50 according to the example includes an ion source 52, an ion acceleration tube 54, a mass analyzer 56, a scanner 58, and a sample chamber 60.

[0025] First, the ePTFE sheet 10, which has a collagen layer 16 formed on the surface of Japanese paper 14 and is to be irradiated with an ion beam, is placed in the sample chamber 60. After that, ions are generated in the ion source 52, and these ions are accelerated by an electric field in the ion acceleration tube 54. The accelerated ions are selected by a mass analyzer 56 to select only ions with a mass required for irradiation. The selected ions are scanned by a scanner 58 so that the entire ePTFE sheet 10 is irradiated. The voltage in the ion acceleration tube 54 is 50 KeV to 200 KeV, and the pressure in the sample chamber 60 is 10 -4 Pa to 10 -5 The pressure is negative at 1 Pa.

[0026] In the case of a hydrophilized ePTFE sheet 10 completed by forming a collagen layer 16 on the surface of Japanese paper 14, platelets in the blood have the property of easily adhering to the surface of the collagen layer 16, so the hydrophilized ePTFE sheet 10 is unsuitable for use in a location where blood may adhere. However, if the surface of the collagen layer 16 is irradiated with an ion beam or electromagnetic waves or electron beams, platelets become less likely to adhere to the surface of the collagen layer 16, and therefore the hydrophilized ePTFE sheet 10 that has been irradiated with an ion beam can be actively used in a location where blood may adhere.

[0027] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0028] 10...hydrophilized ePTFE sheet, 12...ePTFE sheet, 14...Japanese paper, 16...collagen layer 50...ion beam irradiation device, 52...ion source, 54...ion acceleration tube, 56...mass analyzer, 58...scanner, 60...sample chamber

Claims

1. A hydrophilized ePTFE sheet comprising: an ePTFE sheet; Japanese paper laminated on the surface of the ePTFE sheet which has been treated with atmospheric pressure plasma; and a collagen layer applied to the surface of the Japanese paper.

2. The ePTFE sheet according to claim 1, wherein the surface of the collagen layer is irradiated with an ion beam.

3. A method for hydrophilizing an ePTFE sheet, comprising: treating the surface of an ePTFE sheet with atmospheric pressure plasma; laminating Japanese paper on the atmospheric pressure plasma-treated surface; and applying a collagen layer to the surface of the Japanese paper.

4. The hydrophilization method according to claim 3, further comprising irradiating the surface of the collagen layer with an ion beam.

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