JP2620378B2 - Method for producing medical device having surface with excellent biocompatibility - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing a medical device having a surface with excellent biocompatibility.

[Related Art] In recent years, a number of medical devices have been developed with advances in medicine. These medical devices require medical functionality, biocompatibility and economy.

The medical functions include, for example, a function of storing blood in the case of a blood bag, a function of dialyzing or passing blood in the case of an artificial kidney dialysis membrane or a hypermembrane, and a function of blood in the case of an artificial heart. It is a property governed by the shape and mechanical characteristics of the tool, such as the function as a pump and the function as a lens in the case of a contact lens.

The biocompatibility is a property that does not damage the biological components when the medical device comes into contact with the biological components such as a biological tissue and a body fluid, that is, a property that ensures safety. This is a property governed by the surface of medical devices that come into contact with biological components such as blood and body fluids, especially the surface properties of several tens of millimeters.

Currently developed medical devices satisfy the medical functionality, but have the drawback that their use is limited due to insufficient biocompatibility. In particular, medical devices that come into contact with blood have major drawbacks, such as formation of a thrombus at a site that comes into contact with blood and activation of complement.

Under such circumstances, research for improving biocompatibility while securing medical functionality by modifying the surface of medical devices has been actively promoted.

For example, there is a method of performing radiation irradiation or glow discharge treatment on the material surface, and graft-polymerizing a hydrophilic monomer such as acrylamide or ethylene glycol to make the surface hydrophilic, thereby improving biocompatibility.

However, in this method, the apparatus is expensive, so that the economic efficiency is poor. In the case of having a hollow inner surface or a complicated shape, it is difficult to uniformly graft, or the hydrophilic polymer itself is grafted. It has many drawbacks, such as being difficult.

As an example of using a physiologically active substance, a method has been developed in which heparin is slowly released from the surface of a medical device or urokinase is fixed on the surface to prevent thrombus formation.

However, these methods have drawbacks in that the sustained release of heparin ends or the inactivation of urokinase causes the formation of a thrombus, and the molding method and the base material of the medical device are limited and expensive.

On the other hand, compounds having a photosensitive group such as an azide group have been widely applied in the fields of photography, printing technology, adhesion, coating technology and the like, and many azide compounds have been put to practical use especially in the photoresist field. However, no attempt has been made to apply such a technology to a biocompatible medical device.

[Problems to be Solved by the Invention] The present invention has been made to solve the problem that a medical device having medical functionality and economic efficiency and having a surface excellent in biocompatibility has not been developed. It is a thing.

Means for Solving the Problems The present inventors have conducted intensive studies on a method for stably and economically providing a surface having excellent biocompatibility to the surface of a medical device, and as a result, have obtained two or more azides. A composition comprising a compound having a group and a hydrophilic polymer is present on the material surface,
Short-time light irradiation converts the azide group into a reactive nitrene group, forming a covalent bond between the material surface and the hydrophilic polymer or, in addition, the hydrophilic polymer via a nitrogen atom. The inventors have found that a layer made of a hydrophilic polymer is fixed on the surface of the material, and that the above-mentioned problem can be solved. Thus, the present invention has been completed.

That is, in the present invention, a composition comprising a compound having two or more azide groups and a hydrophilic polymer is present on the material surface, and then the hydrophilic polymer is bonded to the material surface by light irradiation. The present invention relates to a method for manufacturing a medical device having a surface having excellent biocompatibility.

[Examples] In the present invention, as described above, a covalent bond via a nitrogen atom is formed between the surface of a material constituting a medical device and a hydrophilic polymer or, in addition, a hydrophilic polymer to form a surface of the material. A layer made of a hydrophilic polymer is immobilized on the substrate, but the covalent bond via the nitrogen atom is formed by the reaction of the azide group in the compound having an azide group.

Examples of the compound having an azide group include a compound having a carbonyl azide group (R-CON ₃ ), a compound having a sulfonyl azide group (R-CO ₂ N ₃ ), and a compound having an aromatic azide group. Although a compound having an aromatic azide group or a compound having a sulfonyl azide group having good stability is preferred. In addition, compounds having an aromatic azide group having an electron-withdrawing substituent such as a nitro group, i-line or g-line sensitive bis azide compounds are known in that they can be converted to nitrene by light having a longer wavelength (> 320 nm). More preferred.

Specific examples of such compounds having an azide group include compounds having two or more azide groups, for example, general bis azide compounds as shown in Table 1 wherein two or more azide groups are introduced in one molecule. But not limited thereto.

Examples of the hydrophilic polymer include, but are not limited to, general synthetic hydrophilic polymers, proteins, polysaccharides, and other polymers having excellent biocompatibility. These may be used alone or in combination of two or more.

Specific examples of the synthetic hydrophilic polymer include, for example, polyacrylamide, polydimethylacrylamide, polyvinyl alcohol, polyethylene glycol, polyhydroxyethyl methacrylate, polyacrylic acid, polyvinyl sulfate, polyallylamine, and copolymers thereof. However, it is not limited to these. Nonionic ones such as polyethylene glycol are preferred in that the body fluid components are not easily adsorbed. Among them, acrylamide-based ones such as polyacrylamide and polydimethylacrylamide having no hydroxyl group are more preferable from the viewpoint of less activation of complement.

Specific examples of the protein include, for example, albumin,
Collagen, gelatin; enzymes such as urokinase, streptokinase, plasminogen activator and the like, but are not limited thereto. Among these, collagen is preferable from the viewpoint of excellent tissue compatibility.

Specific examples of the polysaccharide include heparin, hyaluronic acid, chondroitin sulfate, dermatan sulfate, dextran sulfate, keratan sulfate, heparan sulfate and the like. Of these, heparin is preferred from the viewpoint of the thrombus formation inhibitory effect.

Specific examples of the other polymers having excellent biocompatibility include chitin, prostaglandin, and derivatives thereof.

The hydrophilic polymer is fixed to the surface of the medical device by a covalent bond via a nitrogen atom, and the bond is formed by a nitrene group generated by irradiating the azide group with light, as represented by the following formula. Performing the reaction, ie, the hydrogen abstraction reaction represented by the formula (1), the addition to the double bond or the insertion into the C—H bond represented by the formula (2), and the coupling reaction represented by the formula (3) Is generated by

R-. + R'H → R '. + RH-R-NH-R'
(1) 2R-.fwdarw.RN = NR (3) Since the nitrene group has extremely high reactivity, there may be cases where a small number of bonds other than the above-mentioned reaction are formed, but the nitrene group is substantially hydrophilic. Where the molecule is immobilized on the surface of the medical device via the bond, it is within the scope of the present invention.

In addition, there is a case where the above-mentioned reaction occurs between hydrophilic polymers and cross-linking occurs, and such a case also falls within the scope of the present invention. When the hydrophilic polymer has high water solubility, such crosslinking may be positively caused.

The medical device according to the present invention is used in contact with a biological component such as a biological tissue or a body fluid. Specific examples of such medical devices include, for example, blood bags, urine collection bags, blood transfusion sets, sutures, drain tubes, various catheters, blood access, blood circuits, artificial blood vessels, artificial kidneys, heart-lung machines, artificial valves, plasma exchanges. Membranes, various adsorbents,
Examples include, but are not limited to, CAPD, IABP, pacemakers, artificial joints, artificial heads, dental materials, intraocular lenses, soft contact lenses, and various shunts.

In these medical devices, the entire surface may be a surface having a hydrophilic polymer, or only a portion in contact with a biological component such as a biological tissue or a body fluid may be a surface having a hydrophilic polymer.

 Next, a method for producing the medical device of the present invention will be described.

As a method for causing a composition comprising a compound having two or more azide groups and a hydrophilic polymer used in the present invention to be present on the surface of a material, for example, the composition is dissolved or suspended in a volatile organic solvent such as methanol. A method of forming a thin layer of the composition on the surface of the material by applying or spraying the liquid on the surface of the material, and then contacting an aqueous solution or colloid solution of the composition with the surface of the material, and adsorbing the material on the surface of the material. Method. Further, after a compound having an azide group is present on the surface of a material, a hydrophilic polymer may be present thereon.

The binding of the hydrophilic polymer to the material surface is easily performed by causing a composition comprising a compound having two or more azide groups and the hydrophilic polymer to be present on the material surface and then irradiating the material with light. be able to. When a composition comprising a compound having two or more azide groups and the hydrophilic polymer is used, a special operation for introducing an azide group into the hydrophilic polymer is unnecessary, and the non-fixed substance is removed by washing. Is preferred in that it is easy.

As a light source used for the light irradiation, a high-pressure mercury lamp generally emitting ultraviolet light, a low-pressure mercury lamp, various mercury lamps such as an ultra-high-pressure mercury lamp, an excimer laser, and the like can be used. When used, or when a nitrene group is generated by light of 320 nm or more, such as a compound having an aromatic azide group having a nitro group, by cutting the short wavelength region with a filter, The effect on conductive polymers and materials can be reduced. According to this method, it is particularly preferable to use a hydrophilic polymer such as a protein.

Since the reaction of the nitrene group is completed in a very short time, the irradiation time of the ultraviolet ray may be within 5 minutes.

The method of light irradiation is to irradiate directly to the surface of the material in which the hydrophilic polymer is present, or to irradiate from the side opposite to the surface in which the hydrophilic polymer is present in the case of a material having ultraviolet transmittance. Can also.

In addition, by using an optical fiber, it is possible to irradiate an arbitrary part on the inner surface of a tool having a complicated shape.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Reference Example 1 Using 1 part of acrylamide with respect to 4 parts by weight of N, N-dimethylacrylamide (hereinafter referred to as "parts"), using benzoyl peroxide and N, N-dimethyl-p-toluidyl in acetone as redox-based initiators. Copolymerization was performed.
The formed white precipitate is separated by filtration, sufficiently washed with acetone, and N, N-
A dimethylacrylamide-acrylamide copolymer (hereinafter, referred to as PDMA) was obtained.

The PDMA thus obtained was subjected to Huffman degradation by a well-known method, and the amide group was converted to an amino group (Hiroo Tanaka et al.,
Polymer Journal, 33 , No. 6, p. 309 (1976), "Hoffmann degradation of polyacrylamide", etc.). The reaction mixture was poured into a large amount of acetone to recover the polymer. The dried polymer was dissolved in a small amount of water and acidified with liquid acid.
(Hereinafter referred to as aminated PDMA).

100 mg of the aminated PDMA thus obtained is dissolved in 10 ml of water, triethylamine is added to release the amino group, and 100 mg of a water-soluble azide compound Sulfo-SANPAH (abbreviation, manufactured by PIERCE) shown below is added and dissolved, And left overnight at room temperature. The reaction solution is dialyzed with a dialysis membrane having a cut-off molecular weight of 1000 to remove low molecular impurities, and then freeze-dried to introduce azide group-introduced PDMA (hereinafter referred to as azido-PDMA1).
I got

A methanol solution (about 1% by weight) of the azidated PDMA1 thus obtained was prepared.
After coating and developing on a sample film cut into 2 cm ² , it was air-dried and the solvent was distilled off. The film surface on which the azide PDMA1 was cast was irradiated with ultraviolet rays for 1 minute using a high pressure mercury lamp. Thereafter, the film was sufficiently washed with methanol and water. Each film made of polyethylene terephthalate, polystyrene, or polyurethane was used as a material film.

The film surface having a hydrophilic polymer layer based on azido-PDMA1 by light irradiation has remarkably improved water wettability,
As a result of surface analysis by ESCA, it was confirmed that the hydrophilic polymer layer almost homogeneous was formed over several tens of degrees from the surface.

The obtained film having the hydrophilic polymer layer and the original film not having this layer were immersed in platelet-rich plasma prepared from whole blood of a healthy subject, incubated at 37 ° C. for 1 hour, and then subjected to physiological saline. Rinse with water and fix with glutaraldehyde. Observation of platelet adhesion on these films showed that a large number of platelets adhered to the original film without the hydrophilic polymer layer, but almost no platelets adhered to the film surface having the hydrophilic polymer layer. Platelets were not sticky.

Reference Example 2 100 mg of aminated PDMA and azide compound ANB-NO shown below
SDMA (abbreviation: PIERCE) was used in the same manner as in Reference Example 1 except that PDMA introduced an azide group (hereinafter referred to as azide-modified PD).
MA2). However, methanol was used instead of water as the solvent. The solvent was distilled off, dried, dissolved in a small amount of water, and dialyzed in the same manner as in Reference Example 1 to give azido-modified PD.
MA2 was purified. Then, the surface of the film having a hydrophilic polymer layer based on azido-substituted PDMA2 obtained in the same manner as in Reference Example 1 was remarkably improved in water wettability and almost no platelet adhesion was observed. Also, in surface analysis by ESCA,
As in Reference Example 1, it was confirmed that a hydrophilic polymer layer of several tens of degrees or more was formed.

Reference Example 3 100 mg of aminated PDMA and azide compound HSAB shown below
Reference Example 2 except that 65 mg (obtained by dehydration condensation of abbreviations of p-azidobenzoic acid and N-hydroxysuccinimide with N, N'-dicyclohexylcarbodiimide in dioxane) were used. PDMA with an azide group introduced in the same manner as above (hereinafter referred to as azido-PDMA3)
I got However, HSAB has a small amount of tetrahydrofuran (TH
Dissolved in F) and added. Hereinafter, the azido-PDMA3 was purified in the same manner as in Reference Example 2. On the surface of the film having a hydrophilic polymer layer based on azido-PDMA3 obtained in the same manner as in Reference Example 1, water wettability was remarkably improved, and platelet adhesion was hardly observed. Also, surface analysis by ESCA confirmed that a hydrophilic polymer layer of several tens of degrees or more was formed as in Reference Example 1.

Reference Example 4 Polyacrylamide having an average molecular weight of about 40,000 was subjected to Hoffman degradation in the same manner as in Reference Example 1, and a part of the amide group was converted to an amino group. The reaction mixture solution was poured into a large amount of methanol to recover the polymer. The dried polymer was dissolved in a small amount of water, acidified with hydrochloric acid, then precipitated again from methanol, and polyacrylamide having an amino group introduced therein (hereinafter referred to as “polyacrylamide”).
Aminated PAAm). Aminated PAAm and Sulfo-S
Polyacrylamide having an azido group introduced therein (hereinafter referred to as azido-PAAm) using ANPAH in the same manner as in Reference Example 1.
I got

An aqueous solution (1% by weight) of the azidated PAAm thus obtained was prepared, and the sample film was immersed therein and left for 1 hour. The solution was transmitted while the material film was immersed, and irradiated with ultraviolet light from a high-pressure mercury lamp for 5 minutes. The film was taken out and thoroughly washed with water. A Teflon film and a polystyrene film were used as data films. Azidation obtained
The film surface having a hydrophilic polymer layer based on PAAm,
Water wettability was significantly improved, and platelet adhesion was hardly observed. In addition, by surface analysis by ESCA,
Å It was confirmed that the above hydrophilic polymer layer was formed on the film surface.

Reference Example 5 1 g of bovine serum albumin in 0.15 mol phosphate buffer (pH 8.5)
To give a solution of about 10% by weight. To this was added 10 mg of a water-soluble azide compound Sulfo-SANPAH to dissolve and left in a refrigerator under light shielding to introduce an azide group into albumin.

In this solution, a polystyrene film cut to about 2 cm ² was immersed for 1 hour, and albumin having an azide group introduced was adsorbed on the film surface.

After the film was taken out and rinsed with a physiological saline solution, the film was irradiated with ultraviolet rays for 5 minutes using a high-pressure mercury lamp. However, irradiation was performed using an ultraviolet filter by cutting at a wavelength of 310 nm or less.

 The film was thoroughly washed with saline.

On the surface of the obtained film having the albumin layer, water wettability was remarkably improved and platelet adhesion was hardly observed. In addition, as a result of surface analysis by ESCA, it was confirmed that an albumin layer of several tens of mm or more was formed.

Example 1 10 parts of PDMA obtained in Reference Example 1 was mixed with 1 part of a bisazide compound 2,6-di- (4'-azidobenzylidene) -cyclohexanone and dissolved in methanol to prepare an about 1% by weight solution. did. A polyethylene terephthalate film was used as a reference film, and the operation was carried out in the same manner as in Reference Example 1. Water wettability on the film surface was remarkably improved, and platelet adhesion was hardly observed. As a result of surface analysis by ESCA, it was confirmed that a hydrophilic polymer layer based on PDMA of several tens of mm or more was formed.

Example 2 In acetone, benzoyl peroxide and N, N-dimethyl-p-toluidyl were used as N, N-
Poly (N, N-dimethylacrylamide) (hereinafter referred to as P)
DMAA). Based on 95 parts (by weight) of PDMAA thus obtained, 2,6-di- (4'-azidobenzylidene) -cyclohexanone 5 was used as a bisazide compound.
Parts (weight ratio) were mixed and dissolved in methanol to prepare an approximately 0.1% by weight solution.

About 20 μ of this solution was applied to a sample film cut to about 2 cm ² , developed, and then air-dried to distill off the solvent. The film surface on which the PDMAA containing the bisazide compound was cast was irradiated with ultraviolet rays for 1 minute using a high-pressure mercury lamp. Thereafter, the film was sufficiently washed with methanol and water. As the sample films, films made of polyethylene terephthalate, polystyrene or polyurethane were used.

The surface of the film on which the hydrophilic polymer layer based on PDMAA was immobilized by light irradiation showed remarkable improvement in water wettability and little adhesion of platelets. Further, as a result of surface analysis by ESCA, it was confirmed that the hydrophilic polymer layer was formed almost homogeneously over several tens of degrees from the surface.

Example 3 1 g of bovine serum albumin was added to 0.15 mol phosphate buffer (pH 8.5)
To give a solution of about 10% by weight. In addition, a water-soluble bisazide compound, 4,4'-diazidostilbene-2,2 '
10 mg of sodium disulfonate were added and dissolved.

In this solution, a polystyrene film cut to about 2 cm ² was immersed for 1 hour, and albumin containing a water-soluble bisazide compound was adsorbed on the film surface.

After the film was taken out and rinsed with a physiological saline solution, the film was irradiated with ultraviolet rays for 5 minutes using a high-pressure mercury lamp. However, irradiation was performed using an ultraviolet filter by cutting at a wavelength of 310 nm or less.
Then, the film was sufficiently washed with physiological saline.

The surface of the thus obtained film having an albumin layer was remarkably improved in water wettability, and almost no platelet adhesion was observed. In addition, as a result of surface analysis by ESCA, it was confirmed that an albumin layer of several tens of mm or more was formed.

[Effects of the Invention] The medical device having a surface made of a hydrophilic polymer excellent in biocompatibility according to the present invention exhibits excellent biocompatibility when it comes into contact with a biological component such as a biological tissue or a body fluid, and has high biocompatibility. It has security.

According to the method of the present invention in which a composition comprising a compound having two or more azide groups and a hydrophilic polymer is present on the material surface and then irradiated with light, the hydrophilic polymer can be easily fixed to the surface. It is possible to easily provide a biocompatible surface to existing medical devices and also to materials that lack biocompatibility and are not suitable as medical devices so far, and a wide range of materials can be used as medical devices. Furthermore, since it is a modification of the very surface of the medical device, there is an advantage that the medical function and economic efficiency of the medical device are hardly affected.

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Claims (1)

(57) [Claims] 1. A composition comprising a compound having two or more azide groups and a hydrophilic polymer is made to exist on the surface of a material, and then irradiated with light to bind the hydrophilic polymer to the surface of the material. A method for producing a medical device having a surface excellent in biocompatibility characterized by the above-mentioned.