JPH0318901B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to biocompatible plastic composites for medical use. In particular, it relates to composite materials consisting of a plastic layer and a biocompatible fiber layer. Carbon materials, especially pyrolytic graphite, are widely used as biomaterials and their biocompatibility is well known.
However, pyrolytic graphite or CVD (chemical
vapor deposition (hereinafter abbreviated as CVD)
The treated material is too hard to be used on living organisms. In other words, the physical properties of the materials that make up living organisms are so different that they cannot be replaced.For example, heart valves have a shape that is completely different from the original shape of the heart valve, such as a ball valve. It is processed and used. To perform CVD treatment, the temperature of the base material is raised above the temperature at which hydrocarbons thermally decompose, and carbonization and dehydrogenation occur on the surface, so a heat-resistant base material is inevitably required. Therefore, it is not possible to subject plastic materials to CVD treatments. On the other hand, on the biological side, most of them are made of flexible materials, so there is a need for materials with good biocompatibility and physical properties close to those of living organisms. In order to resolve this contradiction, the inventors invented the following. In other words, we focused on the fact that heat-resistant materials such as metals and inorganic materials exhibit flexibility by making them into thin fibers, and by applying CVD treatment to the fibrous materials and bonding them to plastic materials, we created a system that made the entire material flexible. We attempted to create a material that takes advantage of the biocompatibility of CVD without impairing its properties. However, since the fiber material used here is originally a material that does not stretch or contract, consideration must be given to a method of lamination that does not apply force in the axial direction of the fibers, but rather in the direction of bending the fibers. It is. Twisted yarn used for woven fabrics and the like is generally highly twisted, and when considering its cross section, one filament appears at various locations on each cut surface and never stays in one location. Therefore, if the thickness of the adhesive layer is limited to, for example, less than half the diameter of the twisted yarn, the probability that one filament will be bonded is halved;
The other half can bend freely. Therefore, the thickness of the adhesive layer is preferably less than half the thickness of the fiber layer, and in order to have sufficient flexibility for practical use, the thickness of the adhesive layer is desirably one-fourth or less of the thickness of the fiber layer. The plastic referred to in the present invention includes an elastomer, and may be any general commercially available medical plastic. Plastics such as Teflon, silicone rubber, fluorosilicone rubber, polyethylene, polypropylene, polyester, polyhydroxyethyl methacrylate, polyacrylamide, poly-N-vinylpyrrolidone, segmented polyurethane, or heparin, urokinase, streptokinase, albumin, etc. These include those bonded to or coated with plastic. It is also preferable to apply etching, glow discharge treatment, or a surface treatment agent to these plastics to improve adhesion. The biocompatible fibrous layer can be in the form of braided fibers (including nets), woven fabrics, nonwoven fabrics, felts, and the like. The fibers may be of any heat-resistant type that can withstand CVD treatment, and include carbon fibers, inorganic fibers, such as glass fibers and metal fibers. Preferably, the fiber surface is coated with a biocompatible surface by CVD treatment. This treatment may be carried out in the form of fibers,
The process may be performed after forming the material into braid, woven fabric, non-woven fabric, felt, or the like. CVD is a method of decomposing hydrocarbon gases such as methane, ethylene, propane, butane, benzene, toluene, etc. at a temperature higher than the decomposition temperature of the gas, and coating the fibers with carbon. The temperature is between 600℃ and
The temperature is 3000°C, preferably 1200°C to 2500°C. The above-mentioned biocompatible layer and plastic layer may be bonded using an adhesive, thermocompression bonding, or the like. Adhesives include silicone adhesive, polyethylene-vinyl acetate copolymer,
Examples include polyester, nylon, urethane elastomer, vinyl acetate, and acrylic resin. The non-adhered portions between the fibers are necessary for the flexibility of the entire layer and for the penetration and immobilization of biological cells. Note that the present invention is not limited to a two-layer structure in which a plastic layer and a biocompatible fiber layer are joined together, but may also be a three-layer structure having a plastic layer in the middle and biocompatible fiber layers on both sides. Also, the shape is sheet-like,
It is possible to create an arbitrary shape such as a pipe shape or a tube shape. The biocompatibility of the biocompatible plastic composite material of the present invention was investigated as follows. The cells are epithelial cells derived from established human gingival carcinoma lines (abbreviation
Ca.9.22) and rat fetal tooth germ-derived fibroblast cells (abbreviated as RTG) were used. Each sample was placed in a glass jar with a diameter of 42 mm, and after gas sterilization, 2 to 5 × 10 ⁴
5 ml of cell suspension at cell density/ml was added. 5% for 4 days
Culture was carried out at 37°C under a carbon dioxide atmosphere. Cells grown on the material surface were detached by trypsin treatment, and the number of cells was calculated using a hemocytometer. The number of proliferating cells on a Lux plastic shear for tissue culture was used as a comparative value. Then, the proliferation rate was determined. Example 1 A plain woven fabric made of carbon fibers 14 having a thickness of 0.5 mm was placed on a quartz board 10 using an apparatus as shown in FIG. Argon gas 3 flows at 100c.c./min and methane gas 4 flows at 1c.c./min to form a mixed gas at 1000℃.
It was introduced into a quartz tube 9 in an electric furnace 8 held at The inner diameter of the quartz tube 9 preheated (500° C.) from the trap 1 by the ribbon heater 11 of the electric furnace is 55 mmφ, and the length of the soaking zone is 30 cm. At first, only argon gas 3 was flowed to raise the temperature of the electric furnace to 1000°C, and then methane gas was added to the argon gas and flowed. The mixture was allowed to flow for about 1 hour, and then cooled in an argon atmosphere. The cooled CVD-coated carbon fiber cloth was taken out, placed in a graphite crucible 15 of the apparatus shown in FIG. 2, and heat-treated at a temperature of 2000° C. for 30 minutes in an argon atmosphere.
A carbon fiber cloth (referred to as PG carbon fiber cloth) which had been subjected to temperature cooling and CVD treatment was obtained. In addition, in Fig. 2, the heating element 1
6, graphite electrode 17, heat insulating material 18, copper electrode plate 1
9. Nozoki window 20. Example 2 A polyvinyl chloride sheet measuring 100 mm x 100 mm and 1 mm thick was placed on a flat table, and two layers of cellophane tape were applied to the four sides to create a step of about 1/10 mm. Silicone resin adhesive SILASTIC in its enclosure
Pour Silicon Type A and squeeze it with a glass rod to make it about 1/2 cup.
Form an adhesive layer with a thickness of 10 mm and apply Example 1 from above.
Place the obtained PG carbon fiber cloth on top and press it down.
A polyvinyl chloride and PG carbon fiber cloth composite material was obtained by leaving it as it was for a day and night. Similarly, samples of ion-etched Teflon sheets were prepared. For the silicone rubber sheet, make a paper mold with a square hole, pour the adhesive, and do the same.
A PG carbon fiber cloth composite material was created. All of these materials exhibited sufficient flexibility. After the adhesive had solidified, four samples each having a diameter of 32 mm were cut out from the center. Example 3 The following experiment was conducted to determine biocompatibility.
The cells are epithelial cells derived from established human gingival carcinoma lines (abbreviation
Ca.9.22) and rat fetal tooth germ-derived fibroblastic cells (abbreviated as RTG) were used. Each sample was placed in a glass jar with a diameter of 42 mm, and after gas sterilization, 5 ml of a cell suspension containing 2 to 5 x ¹⁰⁴ cells/ml was added. Culture was carried out at 37° C. in a 5% carbon dioxide atmosphere for 4 days. Cells grown on the material surface were detached by trypsin treatment, and the number of cells was calculated using a hemocytometer. The number of proliferating cells on a Lux plastic shear for tissue culture was used as a comparative value. Cell proliferation on each sample was expressed as proliferation rate. Proliferation rate = (cell concentration of sample) - (cell concentration at start) / (cell concentration of Lux shearle) - (
Cell Concentration at Start) Each sample was measured four times and the average value was determined. The results are shown in the table below.

[Table] Samples with PG carbon fiber cloth layer have increased proliferation rate;
This suggests increased biocompatibility. Samples with carbon fiber fabric layers also showed increased biocompatibility. Example 4 A CVD coating was applied to glass fiber cloth using the method of Example 1. The mixed gas and other conditions were the same as in Example 1, but the CVD coating was performed in an electric furnace at 700°C. One side was not heat treated. obtained
Place the CVD-coated glass fiber cloth and the glass fiber cloth on a flat table, place a 10cm x 10cm 1mm-thick PVC sheet on top coated with silicone adhesive, and press the PVC CVD-coated glass from above. A fiber cloth composite and a polyvinyl chloride glass fiber composite were obtained. Using this, the proliferation rate of epithelial cells (Ca.9.22) was determined under the conditions of Example 3. The former was 75% and the latter 65%.

[Brief explanation of the drawing]

Figures 1 and 2 show the CVD used in the present invention.
FIG. 2 is an explanatory diagram of a processing device. 1... Trap, 2... Mantle heater, 3
...Argon gas, 4...Methane gas, 5,6,
7...Flowmeter, 8...Electric furnace, 9...Quartz tube, 1
0...Quartz board, 11...Ribbon heater, 1
2... Thermocouple, 13... Pit, 14... Carbon fiber cloth, 15... Graphite crucible, 16... Soaking body, 1
7...Graphite electrode, 18...Insulating material, 19...Copper electrode plate, 20...Peephole.

Claims (1)

[Scope of Claims] 1. A biocompatible plastic composite material for medical use formed by bonding a biocompatible fiber layer made of carbon fiber or inorganic fiber and a plastic layer. 2. The plastic composite material according to claim 1, wherein the carbon fiber or inorganic fiber is coated with carbon. 3. The plastic composite material according to claim 1, wherein the plastic layer is a flexible material. 4. The plastic composite material according to claim 3, wherein the flexible material is selected from silicone rubber, fluororesin, and polyvinyl chloride. 5. The plastic composite material according to claim 1, wherein the biocompatible fiber layer is obtained from woven fabric, braided fabric, or felt. 6. A patent claim characterized in that a biocompatible fiber layer made of carbon fiber or inorganic fiber and a plastic layer are bonded together using an adhesive, and the thickness of the adhesive layer is less than half of the thickness of the fiber layer. Range 1st to 5th
A plastic composite according to any one of paragraphs.