JP2005132877A - Hydrophilic material and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrophilic material which is used as a material for medical equipment and its manufacturing process. <P>SOLUTION: The manufacturing process for the hydrophilic material comprises a step in which chitosan is introduced to the surface of the material via a spacer, a step in which the chitosan is treated with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, or a step in which the chitosan is treated with phosphorus oxychloride or phosphoric acid, and a step in which the treated material is neutralized with ammonia or an amine compound. Also the invention relates to a manufacturing process for the hydrophilic material which comprises a step in which chitosan is treated with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, or a step in which the chitosan is treated with phosphorus oxychloride or phosphoric acid, a step in which the chitosan is introduced to the surface of the material via a spacer, and a step in which the treated material is neutralized with ammonia or an amine compound. Also the invention relates to a hydrophilic material to the surface of which an ammonium salt of sulfated or phosphorylated chitosan is chemically bonded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydrophilic substrate in which a sulfated or phosphorylated ammonium salt of chitosan is chemically bonded to the surface of the substrate and a method for producing the same.

  The instruments used in the medical field have the necessary functions, but many of them are insufficient in sustainability for long-term indwelling and procedures. For example, an endoscope or a laparoscope, which is a device for observing the inside of a body cavity, is used for various procedures, and in some cases, it is used while inserted into a living body for 30 minutes or more. However, the inside of the body is hot and humid, and there are various splashes and oily smoke generated by a laser scalpel, etc., and the endoscope and laparoscopic lenses are easily clouded, and are also easily contaminated by gastric juice. For this reason, the procedure may be interrupted and taken out of the body, causing a burden on doctors and patients.

  There have been proposed methods for improving the surface characteristics of materials by chemically modifying materials for medical devices and the like. However, in particular, the hydrophilicity of the material surface does not necessarily reach a sufficient level. For example, when the medical device material is an inorganic material such as glass or silica, or an organic material such as fluororesin or polyvinyl alcohol, it is practical to achieve super hydrophilicity (contact angle with water of 5 degrees or less). There was a considerable problem as a medical device.

For example, a glass product having a coating film including a coating substance arranged in the order of hydrophilic group-water repellent group-bonding group on the surface is disclosed (see Patent Document 1). However, although a phosphorus compound represented by (RO) ₂ PO— is disclosed as a hydrophilic treatment agent, only an ethyl group is used as R, and the structure of the glass product surface after the hydrophilic treatment is biological It is not preferable as a hydrophilic treatment method for a base material used for medical devices because of its low compatibility.

  Moreover, the surface treatment agent which consists of phosphoric acid and / or its salt, a soluble aluminum compound, water-soluble silicate, a nonionic surfactant, and a solvent was apply | coated, and it heat-processed at 300-700 degreeC, and was shape | molded then. A hydrophilic membrane is disclosed (see Patent Document 2). Furthermore, a hydrophilic coating is also disclosed in which a surface treatment agent composed of phosphoric acid, a soluble aluminum compound, a water-soluble silicate and a solvent is applied and then heat treated at 200 to 600 ° C. (see Patent Document 3). However, in both cases, it is described that ammonium phosphate is used as a hydrophilic treatment agent. However, an aluminum compound and a silicate are used together and applied to the surface of the article, and then baked to phosphate on the surface of the article. A three-dimensional cross-linked structure of foralumina silicate is formed, and the structure of the glass product surface after hydrophilization treatment is not preferable as a hydrophilic treatment method for a base material used in medical devices due to low biocompatibility. Met.

  On the other hand, a method of using chitosan as a hydrophilic coating agent has been studied. For example, a chitosan derivative solution such as chitosan, carboxymethyl chitosan, or glycol chitosan is applied to the surface of a non-conductive substance and dried to make the plating layer adhere to the surface of the non-conductive substance such as glass or synthetic resin. A method for forming a conductive film is disclosed (see Patent Document 4). Also disclosed is a method for producing a medical or food film having antibacterial and hydrophilic properties by applying and drying a chitosan organic acid salt solution on the film surface (see Patent Document 5). Chitosan is a substance excellent in biocompatibility, but even when these conventional hydrophilic coating agents comprising chitosan are used as a medical device substrate, sufficient hydrophilicity cannot be obtained.

JP 2002-12450 A JP-A-9-278431 JP-A-9-194234 JP-A-3-271375 JP-A-10-306167

  An object of this invention is to provide the hydrophilic base material which can be used for medical devices, and its manufacturing method.

  The present invention includes a step of introducing chitosan to a substrate surface via a spacer, a step of treating chitosan with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, or chitosan with phosphorus oxychloride or The present invention relates to a method for producing a hydrophilic substrate comprising a step of treating with phosphoric acid and a step of neutralizing the treated substrate with ammonia or an amine compound.

  The present invention also includes a step of treating chitosan with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, a step of treating chitosan with phosphorus oxychloride or phosphoric acid, a spacer on the surface of the substrate. The present invention relates to a method for producing a hydrophilic base material comprising a step of introducing the chitosan via a base and a step of neutralizing the treated base material with ammonia or an amine compound.

  In the production method, the spacer is preferably diisocyanate.

  The present invention also relates to a hydrophilic substrate having a sulfated chitosan ammonium salt or a phosphorylated ammonium salt of chitosan on the surface of the substrate.

  Furthermore, the present invention is a medical device comprising the hydrophilic substrate.

  According to the production method of the present invention, a hydrophilic substrate in which a sulfated or phosphorylated ammonium salt of chitosan is chemically bonded to the substrate surface can be easily and reliably produced. The obtained base material can be used as a medical device material such as an endoscope, a laparoscope, a catheter and a stent, an artificial blood vessel, an artificial organ, an artificial skin, and an artificial organ.

  The first method for producing a hydrophilic substrate of the present invention comprises a step of introducing chitosan to the substrate surface via a spacer, the chitosan is concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid, or sulfuric anhydride. It comprises a step of treating, a step of treating chitosan with phosphorus oxychloride or phosphoric acid, and a step of neutralizing the treated substrate with ammonia or an amine compound.

  Base materials include glass, silica; polysaccharides such as chitin and chitosan; fluorine resins such as tetrafluoroethylene-ethylene copolymer resin (ETFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA); polyvinyl General-purpose polymers and engineering plastics such as alcohol, polylactic acid, polyethylene, polypropylene, polyamide, polyurethane, polyvinyl acetate, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid, and polymethacrylic acid ester can be used. Among these, when using a base material for medical equipment, especially glass and a fluororesin are preferable.

  The substrate is preferably etched on the surface. By etching, an active group is present on the surface of the substrate. The etching method of the substrate surface is not particularly limited. For example, when the substrate is a fluororesin, a solution of sodium naphthalene in tetrahydrofuran (THF) is used. When the substrate is glass, hydrofluoric acid is used. Can be processed.

  As the spacer, diisocyanate compounds such as hexamethylene diisocyanate and tolylene diisocyanate, dialdehydes such as glutaraldehyde, and the like can be used. Of these, hexamethylene diisocyanate is preferred because of its high safety in vivo.

  Chitosan preferably has a weight average molecular weight of 10,000 to 300,000, more preferably 20,000 to 200,000, and even more preferably 100,000 to 150,000. If the weight average molecular weight is less than 10,000, the hydrophilicity is slightly lowered, and if it exceeds 300,000, introduction of hydrophilic groups such as sulfate groups or phosphate groups becomes uneven. The degree of deacetylation of chitosan is preferably 65 to 100%, more preferably 70 to 100%, and still more preferably 80 to 100%. When the degree of deacetylation is less than 65%, the introduction of hydrophilic groups such as sulfate groups or phosphate groups becomes non-uniform.

  The reaction conditions for introducing the spacer onto the substrate surface can be appropriately selected depending on the type of the substrate and the type of the spacer. Usually, as a reaction solvent, formamide, dimethyl sulfoxide, N, N-dimethylformamide, THF, acetone and the like are used, but formamide, dimethyl sulfoxide, N, N-dimethyl are particularly preferred from the viewpoint of polarity and solubility. It is preferable to use formamide. The reaction temperature is preferably 10 to 60 ° C, and more preferably 30 to 50 ° C. When the reaction temperature is low, it takes too much time to introduce the spacer to the surface of the substrate, and when the reaction temperature is high, there is a high possibility that both ends of the spacer will react with the surface of the substrate. The reaction time is preferably 1 to 4 hours, and more preferably 2 to 3 hours. When the reaction time is short, the introduction of the spacer to the substrate surface becomes insufficient, and when the reaction time is long, the possibility that both ends of the spacer react with the substrate surface increases.

  The reaction conditions between the spacer introduced into the substrate surface and chitosan can be appropriately selected depending on the type of spacer. Usually, as a reaction solvent, formamide, dimethyl sulfoxide, N, N-dimethylformamide, THF, acetone or the like is used. In particular, formamide is preferably used from the viewpoints of polarity, solubility, and the like. The reaction temperature is preferably 10 to 60 ° C, and more preferably 30 to 50 ° C. If the reaction temperature is low, the reaction takes too much time, and if the reaction temperature is high, the solvent may evaporate or decompose. The reaction time is preferably 5 to 10 hours, and more preferably 6 to 8 hours. When the reaction time is short, the reaction between the spacer and chitosan is insufficient, there is an unreacted spacer, and when the reaction time is long, the treatment process may be inconvenient.

The amount of chitosan introduced to the surface of the base material via the spacer is preferably 0.01 to 200 μg per 1 cm ² of the base material. If the introduction amount is less than 0.01 μg, the amount covering the substrate is insufficient, and hydrophilicity does not appear or the sustainability tends to be insufficient. If it exceeds 200 μg, the surface tends to be insufficiently smooth and the transparency tends to be insufficient.

  The amount of chitosan introduced is that the substrate into which chitosan is introduced via a spacer is immersed in saturated iodine water for 30 minutes, and then the absorbance (452 nm) of iodine water is measured and compared with a calibration curve prepared in advance. Can be quantified.

  Chitosan introduced to the substrate surface via a spacer is treated with sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid, or anhydrous sulfuric acid, or with phosphorus oxychloride or phosphoric acid. Processed.

  When performing the sulfation treatment, chitosan may be immersed in the treatment liquid, or the treatment liquid may be sprayed or applied to the chitosan. The sulfation treatment time is preferably 0.5 to 3 hours, and more preferably 1 to 2 hours. Moreover, it is preferable that processing temperature is -20-30 degreeC, and it is more preferable that it is -10-20 degreeC. When the treatment time is short or the treatment temperature is low, there are many unreacted parts and the hydrophilicity of the product tends to be insufficient. On the other hand, when the treatment time is long or the treatment temperature is high, the strength or the molecular weight tends to be reduced due to the corrosion or decomposition of chitosan, and the treatment surface tends to be uneven.

  The phosphoric acid and phosphorus oxychloride used for the phosphorylation treatment are preferably used as an aqueous solution having a concentration of 20% by weight or more. When the concentration is low, the reaction time tends to be long or the hydrophilicity of the product tends to be insufficient. When performing the phosphorylation treatment, chitosan may be immersed in the treatment liquid, or the treatment liquid may be sprayed or applied to the chitosan. The phosphorylation treatment time is preferably 0.1 to 10 hours. Moreover, it is preferable that processing temperature is room temperature-170 degreeC. When the treatment time is short or the treatment temperature is low, there are many unreacted parts and the hydrophilicity of the product tends to be insufficient. On the other hand, when the treatment time is long or the treatment temperature is high, the strength or the molecular weight tends to be reduced due to the corrosion or decomposition of chitosan, and the treatment surface tends to be uneven.

  Ammonia or an amine compound is used for the neutralization reaction after the sulfation or phosphorylation treatment. Examples of the amine compound include aliphatic primary amines having 1 to 10 carbon atoms such as methylamine, ethylamine, and propylamine; aliphatic secondary amines having 1 to 10 carbon atoms such as dimethylamine, diethylamine, and dipropylamine; trimethylamine, Examples thereof include aliphatic amines having 1 to 10 carbon atoms such as triethylamine and tripropylamine; aromatic amines such as aniline and diethylaniline; and amino acids such as glycine, alanine, serine, glutamic acid, lysine and arginine. Ammonia and amine compounds are preferably used as an aqueous solution having a concentration of 10% by weight or more. When the concentration is low, the amount of aqueous ammonia solution or aqueous amine compound used for the treatment increases, and the hydrophilicity and yield of the product tend to be insufficient. The neutralization treatment time is preferably from 0.1 minute to 10 hours. When the treatment time is shorter than 0.1 minutes, the reaction is insufficient and the resulting chitosan tends to be insufficient in hydrophilicity or hydrophilicity sustainability. On the other hand, if it exceeds 10 hours, inconvenience may occur in the treatment process. Moreover, it is preferable that the neutralization process temperature is -5-50 degreeC. If the treatment temperature is less than −5 ° C., the solution tends to solidify, and if it exceeds 50 ° C., ammonia or amine compound having a low boiling point tends to vaporize.

  In the chitosan molecule, the reaction sites for sulfation or phosphorylation are the amino group at the C2 position and the hydroxyl groups at the C3 and C6 positions. In the present invention, any of these three functional groups may be sulfated or phosphorylated, but high hydrophilicity can be obtained particularly when only the C6 position is sulfated. Using a 2: 1 mixture of sulfuric acid and chlorosulfonic acid, sulfation is carried out selectively only at the C6 position by sulfating while protecting the amino group at the C2 position and the hydroxyl group at the C3 position. Can do.

  The ratio (introduction rate) of the number of functional groups actually neutralized after sulfation or phosphorylation to the total number of functional groups capable of sulfation or phosphorylation in chitosan is preferably 10 to 100%. If the introduction rate is less than 10%, the hydrophilicity and hydrophilicity of the product tend to be insufficient.

  The second hydrophilic substrate production method of the present invention comprises a step of treating chitosan with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, or chitosan with phosphorus oxychloride or phosphoric acid. It comprises a treatment step, a step of introducing the chitosan to the surface of the substrate via a spacer, and a step of neutralizing the treatment substrate with ammonia or an amine compound.

  As the base material, the spacer and the chitosan, any of the same methods as those for producing the first hydrophilic base material can be used. In addition, the introduction of the spacer onto the surface of the substrate can be performed in the same manner as in the first method for producing a hydrophilic substrate.

  Chitosan is treated with sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid, or sulfuric anhydride, or with phosphorous oxychloride or phosphoric acid.

  When performing the sulfation treatment, chitosan may be immersed in the treatment liquid, or the treatment liquid may be sprayed or applied to the chitosan. The sulfation treatment time is preferably 0.5 to 3 hours, and more preferably 1 to 2 hours. Moreover, it is preferable that processing temperature is -20-30 degreeC, and it is more preferable that it is -10-20 degreeC. When the treatment time is short or the treatment temperature is low, there are many unreacted parts and the hydrophilicity of the product tends to be insufficient. On the other hand, when the treatment time is long or the treatment temperature is high, the strength or the molecular weight tends to be reduced due to the corrosion or decomposition of chitosan, and the treatment surface tends to be uneven.

  The phosphoric acid and phosphorus oxychloride used for the phosphorylation treatment are preferably used as an aqueous solution having a concentration of 20% by weight or more. When the concentration is low, the reaction time tends to be long or the hydrophilicity of the product tends to be insufficient. When performing the phosphorylation treatment, chitosan may be immersed in the treatment liquid, or the treatment liquid may be sprayed or applied to the chitosan. The phosphorylation treatment time is preferably 0.1 to 10 hours. Moreover, it is preferable that processing temperature is room temperature-170 degreeC. When the treatment time is short or the treatment temperature is low, there are many unreacted parts and the hydrophilicity of the product tends to be insufficient. On the other hand, when the treatment time is long or the treatment temperature is high, the strength or the molecular weight tends to be reduced due to the corrosion or decomposition of chitosan, and the treatment surface tends to be uneven.

  In the chitosan molecule, the reaction sites for sulfation or phosphorylation are the hydroxyl groups at the C2 and C6 positions and the amino group at the C3 position. In the present invention, any of these three functional groups may be sulfated or phosphorylated, but high hydrophilicity can be obtained particularly when only the C6 position is sulfated. Use a 2: 1 mixture of sulfuric acid and chlorosulfonic acid to protect the amino group at the C2 position and the hydroxyl group at the C3 position while protecting them so that the sulfation reaction occurs selectively only at the C6 position. Can do.

  The ratio (introduction rate) of the number of functional groups neutralized after actual sulfation or phosphorylation to the total number of functional groups in chitosan capable of sulfation or phosphorylation in chitosan is 20 to 100% Is preferred. If the introduction rate is less than 20%, the hydrophilicity and hydrophilicity of the product tend to be insufficient.

  Reaction conditions between the spacer introduced on the substrate surface and chitosan treated with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid or sulfuric anhydride, or chitosan treated with phosphoric acid or phosphorus oxychloride Can be appropriately selected depending on the type of spacer. Usually, as a reaction solvent, formamide, dimethyl sulfoxide, N, N-dimethylformamide, THF, acetone or the like is used. In particular, formamide is preferably used from the viewpoints of polarity, solubility, and the like. The reaction temperature is preferably 10 to 60 ° C, and more preferably 30 to 50 ° C. If the reaction temperature is low, the reaction takes too much time, and if the reaction temperature is high, the solvent may evaporate or decompose. The reaction time is preferably 5 to 10 hours, and more preferably 6 to 8 hours. When the reaction time is short, the reaction between the spacer and the chitosan derivative is insufficient, there is an unreacted spacer, and when the reaction time is long, the treatment process may be inconvenient.

The amount of the sulfated or phosphorylated chitosan introduced to the substrate surface via the spacer is preferably 0.01 to 200 μg per 1 cm ^{2 of the} substrate. If the introduction amount is less than 0.01 μg, the amount covering the equipment is insufficient, and there is a tendency that hydrophilicity does not appear or sustainability is insufficient. If it exceeds 200 μg, the surface tends to be insufficiently smooth and the transparency tends to be insufficient.

  The neutralization reaction of the sulfated or phosphorylated chitosan introduced to the substrate surface through the spacer can be performed in the same manner as in the first method for producing a hydrophilic substrate.

  The hydrophilic base material of the present invention obtained by the first and second production methods has a high hydrophilicity because the sulfated or phosphorylated ammonium salt of chitosan is chemically bonded to the surface of the base material. . When a water droplet is dropped on the hydrophilic substrate surface of the present invention, the contact angle between the water droplet and the hydrophilic substrate surface is preferably 5 ° C. or less. When the contact angle exceeds 5 degrees, the hydrophilicity and anti-fogging property tend to be insufficient when a hydrophilic substrate is used for a medical device or the like.

  The hydrophilic base material of the present invention, in which sulfated or phosphorylated ammonium salt of chitosan is chemically bonded to the base material surface, has a structure similar to that of vascular endothelium (biological membrane) and is blood compatible. Furthermore, it can be suitably used for medical materials such as endoscopes, laparoscopes, catheters, stents, and other medical devices, artificial blood vessels, artificial organs, artificial skins, and artificial organs.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

Example 1
<Activation of polytetrafluoroethylene (PTFE) film>
A PTFE film (size: 1 mm thick, 15 mm × 15 mm square) was soaked for 120 seconds in Tetra Etch (trade name, manufactured by Junkosha Co., Ltd., sodium naphthalene in tetrohydrofuran solution). After washing twice with ethanol and once with ion-exchanged water, it was dried to obtain an activated PTFE film.

<Introduction of hexamethylene diisocyanate>
The activated PTFE film was put into 10 ml of hexamethylene diisocyanate (98%) and stirred at 50 ° C. for 2 hours to be reacted. The film in the reaction solution was taken out and washed with 20 ml of diethyl ether to obtain a PTFE film introduced with hexamethylene diisocyanate.

<Introduction of chitosan>
A PTFE film in which hexamethylene diisocyanate was introduced was placed in 10 ml of formamide in which 0.05 g of water-soluble chitosan (weight average molecular weight 30000, deacetylation degree 95%) was dissolved, and the mixture was stirred at 50 ° C. overnight to be reacted. It was. The film in the reaction solution was taken out and washed with ion exchange water to obtain a PTFE film into which chitosan was introduced.
The obtained film was immersed in saturated iodine water for 30 minutes, and then the absorbance (452 nm) of iodine water was measured, and the amount of chitosan introduced was measured by comparing with a calibration curve prepared in advance. The amount of chitosan introduced was 7.04 μg / cm ² .

<Sulphation reaction and neutralization reaction>
In 18 ml of ice-cold pyridine, 4.2 ml of chlorosulfonic acid was added dropwise to form chlorosulfonic acid pyridine salt. The produced pyridine salt of chlorosulfonic acid was dissolved by heating to 65 ° C., and a PTFE film into which chitosan was introduced was added and reacted at 65 ° C. for 2 hours. The film was taken out and washed with ion-exchanged water, and then stirred at 25 ° C. in 10 ml of aqueous ammonia to react to obtain a PTFE film into which the sulfated ammonium salt of chitosan was introduced.
It was confirmed by FT-IR measurement, elemental analysis, and the like that sulfation reaction and neutralization reaction occurred at C2, C3 and C6 positions of chitosan introduced into the obtained film. Further, the ratio (introduction rate) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was completely decomposed by adding nitric acid to the sample, and then barium sulfate (BaSo ₄ ). When determined by the method, the introduction rate was 15%.
After dripping water, the film was photographed from the side and measured for contact angle, and the hydrophilicity of the obtained film was evaluated according to the following criteria. The results are shown in Table 1.
◎: 5 ° or less ○: 10 ° or less ×: 15 ° or less

Example 2
<Sulfation of chitosan>
When 0.4 g of powdered chitosan (weight average molecular weight 150,000, deacetylation degree 85%) was added to 8 ml of concentrated sulfuric acid and stirred at −20 ° C. for 2 hours, the mixture became gelatinous. While stirring at −20 ° C., 10 ml of cold ether was added. The precipitate was collected by centrifugation, washed several times with ether, and then vacuum dried to obtain sulfated chitosan.

<Introduction of sulfated chitosan>
0.1 g of sulfated chitosan was dissolved in 10 ml of formamide, a PTFE film into which hexamethylene diisocyanate obtained in the same manner as in Example 1 was introduced, and stirred at room temperature overnight to react. The film in the reaction solution was taken out and washed with ion exchange water to obtain a film into which sulfated chitosan was introduced.
The amount of chitosan introduced into the film was 2.32 μg / cm ² .

<Neutralization reaction>
0.56 g of the obtained film was placed in 10 ml of aqueous ammonia, stirred at 25 ° C., and reacted to obtain a PTFE film into which the ammonium salt structure of sulfated chitosan was introduced.
It was confirmed that sulfation reaction and neutralization reaction occurred at C2, C3 and C6 positions of chitosan. Further, the ratio (introduction ratio) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was 15%.
The hydrophilicity of the obtained film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
<Sulfation of chitosan>
Powdered chitosan (weight average molecular weight 150,000, deacetylation degree 85%) 0.2 g was added at 0-4 ° C. to a mixed solution of concentrated sulfuric acid 8 ml and chlorosulfonic acid 4 ml, and the solution was stirred for 60 minutes while returning to room temperature. did. The product was precipitated by dropwise addition of cold ether, and the precipitate was collected by centrifugation, then washed several times with ether and vacuum dried.

<Introduction of sulfated chitosan>
0.1 g of sulfated chitosan was dissolved in 10 ml of formamide, a PTFE film into which hexamethylene diisocyanate obtained in the same manner as in Example 1 was introduced, and stirred at room temperature overnight to react. The film in the reaction solution was taken out and washed with ion exchange water to obtain a film into which sulfated chitosan was introduced.
The amount of chitosan introduced into the film was 4.68 μg / cm ² .

<Neutralization reaction>
0.56 g of the obtained film was placed in 10 ml of aqueous ammonia, stirred at 25 ° C., and reacted to obtain a PTFE film into which the ammonium salt structure of sulfated chitosan was introduced.
It was confirmed that a sulfation reaction and a neutralization reaction occurred at the C6 position of chitosan. Further, the ratio (introduction ratio) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was 15%.
The hydrophilicity of the obtained hydrophilic substrate was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
<Activation of glass>
Glass (size: thickness 1 mm, 15 mm × 15 mm square) was immersed in 20 ml of 5% hydrofluoric acid for 60 seconds. After washing twice with ion exchange water, it was dried to obtain surface activated glass.

<Introduction of hexamethylene diisocyanate>
The surface activated glass was put into 10 ml of hexamethylene diisocyanate (98%) and stirred at room temperature for 2 hours to be reacted. The glass in the reaction solution was taken out and washed with 20 ml of diethyl ether to obtain a glass into which hexamethylene diisocyanate was introduced.

<Introduction of chitosan>
The glass into which hexamethylene diisocyanate was introduced was placed in 10 ml of formamide in which 0.05 g of water-soluble chitosan (weight average molecular weight 30000, deacetylation degree 95%) was dissolved, and the mixture was allowed to react at room temperature overnight with stirring. The glass in the reaction solution was taken out and washed with ion exchange water to obtain a glass into which chitosan was introduced.
The amount of chitosan introduced into the glass was 6.84 μg / cm ² .

<Sulphation reaction and neutralization reaction>
In 18 ml of ice-cold pyridine, 4.2 ml of chlorosulfonic acid was added dropwise to form chlorosulfonic acid pyridine salt. The produced pyridine salt of chlorosulfonic acid was dissolved by heating to 65 ° C., and a glass into which chitosan was introduced was added and reacted at 65 ° C. for 2 hours. The glass was taken out and washed with ion-exchanged water, and then stirred at 25 ° C. in 10 ml of aqueous ammonia to cause a reaction, whereby a glass into which a sulfated ammonium salt structure of chitosan was introduced was obtained.
It was confirmed by FT-IR measurement, elemental analysis, and the like that sulfation reaction and neutralization reaction occurred at C2, C3, and C6 positions of chitosan introduced into the obtained glass. Further, the ratio (introduction ratio) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was 15%.
The hydrophilicity of the obtained film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Example 5
<Sulfation of chitosan>
When 0.4 g of powdered chitosan (weight average molecular weight 150,000, deacetylation degree 85%) was added to 8 ml of concentrated sulfuric acid and stirred at −20 ° C. for 2 hours, the mixture became gelatinous. While stirring at −20 ° C., 10 ml of cold ether was added. The precipitate was collected by centrifugation, washed several times with ether, and then vacuum dried.

<Introduction of sulfated chitosan>
0.1 g of sulfated chitosan was dissolved in 10 ml of formamide, and a glass into which hexamethylene diisocyanate obtained in the same manner as in Example 4 was introduced was stirred and reacted at room temperature overnight. The glass in which the sulfated chitosan was introduced was obtained by taking out the glass from the reaction solution and washing with ion exchange water.
The amount of chitosan introduced into the glass was 2.12 μg / cm ² .

<Neutralization reaction>
The obtained glass was put into 10 ml of aqueous ammonia and stirred at 25 ° C. to cause a reaction, thereby obtaining a glass into which a sulfated chitosan ammonium salt structure was introduced.
It was confirmed that sulfation reaction and neutralization reaction occurred at C2, C3 and C6 positions of chitosan. Further, the ratio (introduction ratio) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was 15%.
The hydrophilicity of the obtained film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
<Sulfation of chitosan>
Powdered chitosan (weight average molecular weight 150,000, deacetylation degree 85%) 0.2 g was added at 0-4 ° C. to a mixed solution of concentrated sulfuric acid 8 ml and chlorosulfonic acid 4 ml, and the solution was stirred for 60 minutes while returning to room temperature. did. The product was precipitated by dropwise addition of cold ether, and the precipitate was collected by centrifugation, then washed several times with ether and vacuum dried.

<Introduction of sulfated chitosan>
0.1 g of sulfated chitosan was dissolved in 10 ml of formamide, and a glass into which hexamethylene diisocyanate obtained in the same manner as in Example 4 was introduced was stirred and reacted at room temperature overnight. The glass in which the sulfated chitosan was introduced was obtained by taking out the glass from the reaction solution and washing with ion exchange water.
The amount of chitosan introduced into the glass was 4.48 μg / cm ² .

<Neutralization reaction>
The obtained glass was put into 10 ml of aqueous ammonia and stirred at 25 ° C. to cause a reaction, thereby obtaining a glass into which a sulfated chitosan ammonium salt structure was introduced.
It was confirmed that a sulfation reaction and a neutralization reaction occurred at the C6 position of chitosan. Further, the ratio (introduction ratio) of the number of functional groups that were sulfated and neutralized to the total number of functional groups capable of being sulfated in chitosan was 15%.
The hydrophilicity of the obtained film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Claims (5)

Introducing chitosan to the substrate surface via a spacer, treating chitosan with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid, or anhydrous sulfuric acid, or treating chitosan with phosphorus oxychloride or phosphoric acid And a method for producing a hydrophilic substrate comprising a step of neutralizing the treated substrate with ammonia or an amine compound. Treating chitosan with concentrated sulfuric acid, chlorosulfonic acid, a mixture of concentrated sulfuric acid and chlorosulfonic acid, or anhydrous sulfuric acid, or treating chitosan with phosphorous oxychloride or phosphoric acid; A method for producing a hydrophilic substrate comprising a step of introducing, and a step of neutralizing the treated substrate with ammonia or an amine compound. The method for producing a hydrophilic substrate according to claim 1 or 2, wherein the spacer is diisocyanate. A hydrophilic substrate having an ammonium salt of sulfated chitosan or an ammonium salt of phosphorylated chitosan on the surface of the substrate. A medical device comprising the hydrophilic substrate according to claim 4.