JP7399017B2 - Silicone member and its manufacturing method - Google Patents

Description

The present invention relates to a silicone member used as a microdevice and a method for manufacturing the same.

A microdevice accommodates a sample in a fine depression (well) or groove and performs various operations such as inspection, reaction, extraction, separation, and measurement. Silicone is often used as a material for members constituting microdevices because it is easy to form fine irregularities and has excellent light transmittance and chemical resistance.

A member made of silicone has a lower affinity for water than a member made of glass. For this reason, when a hydrophilic liquid is made to flow through a fine channel, there is a possibility that a desired operation cannot be performed accurately due to poor flowability. Furthermore, when a microdevice is constructed by joining two members, such as a main body member and a lid member, there is a risk that the joined portion may peel off due to the pressure during liquid feeding. Further, depending on the operation, there is a problem that the component to be captured is difficult to enter the storage part, and when a chemical solution containing protein is flowed, the protein is adsorbed to the storage part. For this reason, when using a silicone member, a treatment may be performed to impart hydrophilicity to the housing portion such as the flow path.

Japanese Patent Application Publication No. 2006-181407 JP2008-82961A International Publication No. 2014/084219

As a treatment for imparting hydrophilicity to the surface of a silicone member (silicone member), a CVD (chemical vapor deposition) method can be mentioned. However, many hydrophilic thin films formed by the CVD method have a hardness close to that of glass, so they tend to crack or peel due to stress differences with silicone, making it difficult to maintain hydrophilicity. Furthermore, methods of modifying the surface by ultraviolet irradiation, excimer light irradiation, plasma treatment, etc. are also known. However, since the molecular skeleton of silicone has a helical structure, the hydrophilic groups generated on the surface by modification sneak into the interior within a short time after the modification treatment due to the rotation of the helical structure. Therefore, the modification effect achieved by these methods is temporary, and the current situation is that it is difficult to maintain the imparted hydrophilicity for 24 hours.

In this regard, Patent Document 1 discloses that a polydimethylsiloxane (PDMS) sheet is made to contain a polyether-modified surfactant, its surface is modified by plasma treatment or excimer light irradiation, and then an organosilane film is formed. A method of forming is described. However, in the method described in Patent Document 1, the PDMS sheet needs to contain a surfactant, so the materials are restricted. In addition, as described in paragraph [0031] of the same document, a three-stage treatment consisting of a temporary hydrophilic treatment with a surfactant, a surface modification treatment, and a secondary hydrophilic treatment with an organosilane solution is essential. Therefore, the manufacturing process is complicated.

On the other hand, Patent Document 2 describes plasma treatment, corona discharge treatment, and surface coating treatment with a hydrophilic polymer as methods for reducing the contact angle of the microchannel with water to 60° or less (making it hydrophilic). . Additionally, Patent Document 3 describes betaine monomers and alkoxysilyl group-containing compounds as hydrophilic coating agents for forming coatings with excellent hydrophilicity, antifogging properties, and water resistance in antifogging films, antireflection films, etc. An alkoxysilyl group-containing polymer obtained by polymerizing a monomer component having the following is described. In these documents, it is described that a coating made of a hydrophilic polymer is formed on the surface of a base material to impart hydrophilicity, but when the base material is made of silicone, the coating The sustainability of hydrophilicity has not been investigated. Moreover, in Patent Document 3, since microdevices are not envisioned as a use of the hydrophilic coating agent, there is no description of forms or methods that can be applied to minute wells or grooves.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a silicone member for a microdevice having a flexible hydrophilic layer that remains hydrophilic for a long time. Another object of the present invention is to provide a manufacturing method that can easily manufacture the silicone member.

(1) In order to solve the above problems, the silicone member of the present invention is a silicone member that is used as a microdevice and has a housing section in which a sample is accommodated, or that divides and forms the housing section by combining with a mating member. The accommodating portion has a silicone body and a hydrophilic layer disposed on the surface of the silicone body, and the hydrophilic layer has a hydrophilic structure and a hydroxyl group chemically bonded to the silicone body. It is characterized by being made of a silicone polymer and fixed to the silicone body by chemical bonding through the hydroxyl groups.

(2) As an example of the method for manufacturing the silicone member of the present invention described in (1) above, the method for manufacturing the silicone member of the present invention includes modifying one side of the silicone body on the side that has the accommodation portion or forms the partition. a modification treatment step in which the one surface is treated with a hydroxyl group; and the one surface is brought into contact with a polymer solution containing the hydrophilic polymer to chemically convert the hydroxyl group of the silicone body and the hydroxyl group of the hydrophilic polymer. It is characterized by comprising a hydrophilic layer forming step of forming the hydrophilic layer on the one surface by bonding.

(1) The silicone member accommodating portion of the present invention includes a silicone body and a hydrophilic layer made of a hydrophilic polymer. The hydrophilic layer is formed from a hydrophilic polymer having a hydrophilic structure and hydroxyl groups chemically bonded to the silicone body. The hydrophilic polymer and the silicone main body are chemically bonded by the reaction of their hydroxyl groups. In the hydrophilic layer, due to the number of bonding sites by hydroxyl groups and steric hindrance of molecular chains having a hydrophilic structure, even if the molecular skeleton of silicone rotates, the hydrophilic structure is difficult to penetrate inside. Therefore, in the silicone member of the present invention, the hydrophilicity of the hydrophilic layer lasts for a long time. Furthermore, since it is made of a hydrophilic polymer that is more flexible than glass, the hydrophilic layer is less likely to crack or peel off. This is also a factor in extending the duration of hydrophilicity.

As described above, the housing portion of the silicone member of the present invention has a flexible hydrophilic layer that remains hydrophilic for a long time, so that various operations such as tests and reactions can be performed accurately using a hydrophilic liquid. can. In addition, since the fluidity is good, the pressure during liquid feeding is less likely to increase. Therefore, when a microdevice is constructed by joining two members, peeling of the joined portion is also suppressed.

(2) In the method for manufacturing a silicone member of the present invention, first, in a modification treatment step, hydroxyl groups are added to one surface of the silicone body including the housing portion. Next, in the hydrophilic layer forming step, a polymer solution is brought into contact with the one surface to chemically bond the hydroxyl groups of the silicone body and the hydroxyl groups of the hydrophilic polymer, thereby forming a hydrophilic layer. As described above, according to the manufacturing method of the present invention, it is possible to easily manufacture a silicone member having a flexible hydrophilic layer that remains hydrophilic for a long time in the housing portion.

It is a perspective view of the silicone member of a first embodiment. 2 is a sectional view taken along line II-II in FIG. 1. FIG. FIG. 7 shows a plan view of a microdevice including a silicone member according to a second embodiment. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. The perspective view of the silicone member of a third embodiment is shown. 1 is a graph showing changes over time in water contact angles of test pieces of Example 1 and Comparative Examples 1 and 7. 3 is a graph showing changes over time in water contact angles of test pieces of Example 2 and Comparative Example 2. 3 is a graph showing changes over time in water contact angles of test pieces of Examples 3 and 4. 3 is a graph showing changes over time in water contact angles of test pieces of Comparative Examples 4 to 6.

Embodiments of the silicone member of the present invention and its manufacturing method will be described below.

<First embodiment>
First, the structure of the silicone member of the first embodiment will be explained. FIG. 1 shows a perspective view of the silicone member of the first embodiment. FIG. 2 shows a cross-sectional view taken along line II-II in FIG. In FIG. 1, the transparent parts are shown by thin lines. As shown in FIG. 1, the silicone member 10 has a rectangular thin plate shape. A housing portion 11 is recessed in the upper surface of the silicone member 10 . The housing portion 11 has a groove portion 12 and two holes 13a and 13b. The groove portion 12 has a linear shape extending in the left-right direction, and both left and right ends thereof are connected to the two holes 13a and 13b. The two holes 13a and 13b each have a circular opening. As shown in FIG. 2, the depth T of the groove portion 12 (accommodating portion 11) is 100 μm, and the width (length in the front-rear direction) W of the groove portion 12 is 100 μm. For example, the sample liquid is injected from the hole 13a, flows through the groove 12, and is taken out from the hole 13b. In this way, the silicone member 10 has the accommodating portion 11 itself and is used alone as a microdevice.

The silicone member 10 has a silicone main body 14 and a hydrophilic layer 15. The silicone main body 14 is made of silicone rubber. The hydrophilic layer 15 is arranged to cover the entire upper surface of the silicone main body 14 including the accommodating part 11. The hydrophilic layer 15 is made of an alkoxysilyl group-containing polymer. The alkoxysilyl group-containing polymer has a trisilanol group at the end as a hydroxyl group that chemically bonds with the silicone body 14, a sulfoxybetaine structure as a hydrophilic structure, and a mass average molecular weight of 500. Alkoxysilyl group-containing polymers are included in the concept of hydrophilic polymers in the present invention. The hydrophilic layer 15 is fixed to the silicone body 14 through a chemical bond between a trisilanol group (hydroxyl group) and a hydroxyl group on the silicone body 14 .

The thickness of the hydrophilic layer 15 in the housing part 11 is 100 nm. The visible light transmittance of the housing part 11 is 88.5%, and the intensity of autofluorescence when irradiated with excitation light having a wavelength of 280 nm or more and 600 nm or less is 9.0. The type A durometer hardness of the upper surface of the silicone member 10 (the upper surface of the hydrophilic layer 15) is A59.

Next, a method for manufacturing the silicone member of this embodiment will be explained. First, in a modification treatment step, the upper surface of the silicone body 14 in which the housing portion 11 is recessed is subjected to a modification treatment. The modification treatment is performed by irradiating the upper surface of the silicone body 14 with microwave plasma in a gas atmosphere containing argon and oxygen. As a result, hydroxyl groups are added to the upper surface of the silicone main body 14. Next, in a hydrophilic layer forming step, an alkoxysilyl group-containing polymer is dip coated on the upper surface of the silicone body 14. That is, the silicone body 14 is immersed in an aqueous solution (viscosity 10 mPa·s) of an alkoxysilyl group-containing polymer, then pulled up, and subjected to a drying process to remove the hydroxyl groups added to the upper surface of the silicone body 14 and the terminal ends of the alkoxysilyl group-containing polymer. Chemically bonds with hydroxyl group. In this way, the hydrophilic layer 15 is formed on the upper surface of the silicone body 14 including the accommodating portion 11.

Next, the effects of the silicone member of this embodiment will be explained. The housing portion 11 of the silicone member 10 has a hydrophilic layer 15 made of an alkoxysilyl group-containing polymer. The alkoxysilyl group-containing polymer is bonded to the silicone body 14 at multiple locations through chemical bonds between hydroxyl groups, and has a long molecular chain containing a hydrophilic structure. Due to the large number of bonding sites and the steric hindrance of long molecular chains, it is difficult for the hydrophilic structure to penetrate inside even when the silicone molecular skeleton rotates. Therefore, in the silicone member 10, the hydrophilicity of the hydrophilic layer 15 continues for a long time. Specifically, as shown in Examples described later, a state in which the water contact angle is 60° or less is maintained for at least 24 hours after the hydrophilic layer 15 is formed.

The thickness of the hydrophilic layer 15 is 100 nm, which is extremely thin. Therefore, even when applied to the groove portion 12, which is a fine flow path, the flow of the liquid is hardly inhibited. Further, the type A durometer hardness measured on the upper surface of the silicone member 10 (the part where the hydrophilic layer 15 is formed) is A59. That is, the hydrophilic layer 15 is more flexible than glass. Therefore, the hydrophilic layer 15 is less likely to crack or peel off, and its hydrophilicity remains for a long time. As described above, since the accommodating portion 11 of the silicone member 10 has a flexible hydrophilic layer 15 with a long duration of hydrophilicity, various operations such as tests and reactions can be performed accurately using a hydrophilic liquid. can. Furthermore, even though the hydrophilic layer 15 is formed, the visible light transmittance of the accommodating portion 11 is high, and the inherent transparency of silicone rubber is not impaired. Since the autofluorescence of the housing part 11 is also weak, it is suitable for optical inspection, etc. in which the housing part 11 is irradiated with light and extremely weak luminescence is observed. Furthermore, even if the sample contains protein, the protein is unlikely to be adsorbed to the storage portion 11.

In the method for manufacturing the silicone member 10, before forming the hydrophilic layer 15, hydroxyl groups are added to the upper surface of the silicone body 14 including the housing portion 11 in a modification treatment step. Thereby, in the subsequent hydrophilic layer forming step, the hydrophilic layer 15 can be easily formed by dip coating the alkoxysilyl group-containing polymer. At this time, since the viscosity of the aqueous solution of the alkoxysilyl group-containing polymer is relatively low, a thin hydrophilic layer 15 can be formed. Moreover, since the solvent of the aqueous solution is water, it is difficult to seep into the hydrophobic silicone body 14. Therefore, during dip coating, there is little risk that the silicone main body 14 will swell and the size of the accommodating portion 11 will change.

<Second embodiment>
The main difference between the silicone member of this embodiment and the silicone member of the first embodiment is that in this embodiment, the microdevice is composed of two silicone members. First, the configuration of a microdevice including the silicone member of this embodiment will be explained. FIG. 3 shows a plan view of the microdevice. FIG. 4 shows a cross-sectional view taken along the line IV-IV in FIG. 3. In FIG. 3, the transparent parts are indicated by thin lines. As shown in FIGS. 3 and 4, the microdevice 20 has a rectangular thin plate shape as a whole. The microdevice 20 includes a first silicone member 30 and a second silicone member 40.

The first silicone member 30 has a rectangular thin plate shape. The configuration of the first silicone member 30 is the same as the configuration of the silicone member 10 of the first embodiment except for the configuration of the hydrophilic layer. That is, the upper surface of the first silicone member 30 is provided with a recessed housing portion 31 . The housing portion 31 has a groove portion 32 and two holes 33a and 33b. The groove portion 32 has a linear shape extending in the left-right direction. The depth (length in the vertical direction) of the groove portion 32 is 100 μm, and the width (length in the front and back direction) is 100 μm. The first silicone member 30 has a silicone body 34 and a hydrophilic layer 35. The hydrophilic layer 35 is arranged to cover the entire upper surface of the silicone main body 34 including the accommodating part 31.

Hydrophilic layer 35 is made of polyvinyl alcohol (PVA). PVA has a hydroxyl group as a hydrophilic structure in its side chain, a part of which is chemically bonded to the silicone body 34. The mass average molecular weight of PVA is 20,000. PVA is included in the concept of hydrophilic polymer in the present invention. The hydrophilic layer 35 is fixed to the silicone body 34 through a chemical bond between the hydroxyl group of the side chain of PVA and the hydroxyl group of the silicone body 34 . The thickness of the hydrophilic layer 35 in the housing part 31 is 100 nm. The visible light transmittance of the housing section 31 is 87.8%, and the intensity of autofluorescence when irradiated with excitation light having a wavelength of 280 nm or more and 600 nm or less is 9.1. The type A durometer hardness of the upper surface of the first silicone member 30 (the upper surface of the hydrophilic layer 35) is A60.

The method for manufacturing the first silicone member 30 is as follows. First, in the same manner as in the first embodiment, the upper surface of the silicone main body 34 in which the accommodating portion 31 is recessed is subjected to a modification treatment. Next, the top surface of the silicone body 34 is dip coated with PVA. That is, the silicone body 34 is immersed in a PVA aqueous solution (viscosity 7 Pa·s) and then pulled up and dried to chemically bond the hydroxyl groups provided on the upper surface of the silicone body 34 and the hydroxyl groups on the side chains of PVA. In this way, the hydrophilic layer 35 is formed on the upper surface of the silicone main body 34 including the accommodating portion 31.

The second silicone member 40 has a rectangular thin plate shape with the same size as the first silicone member 30. The second silicone member 40 is laminated on the upper surface of the first silicone member 30. The second silicone member 40 has a housing section 43 consisting of two holes 41 and 42. The two holes 42 and 43 each have a cylindrical shape and penetrate the second silicone member 40 in the thickness direction (vertical direction). The second silicone member 40 has a silicone main body 44 and a hydrophilic layer 45. The hydrophilic layer 45 is arranged to cover the entire surface of the accommodating portion 43 and the upper surface of the silicone body 44 . The structure of the hydrophilic layer 45 is the same as the structure of the hydrophilic layer 35 of the first silicone member 30. That is, the hydrophilic layer 45 is made of PVA and has a thickness of 100 nm.

The method of manufacturing the second silicone member 40 is also the same as the method of manufacturing the first silicone member 30. That is, after the surface of the accommodating portion 43 and the upper surface of the silicone body 44 are modified, PVA is dip coated. Then, the first silicone member 30 and the second silicone member 40 are stacked on top of each other, and the portions excluding the accommodating portions 31 and 43 are joined to manufacture the microdevice 20. The first silicone member 30 and the second silicone member 40 may be joined together after plasma treating their respective joint surfaces (the hydrophilic layer 35 on the upper surface of the silicone body 34 and the hydrophilic layer 45 on the lower surface of the silicone body 44). .

The left hole 33a of the first silicone member 30 is connected to the lower end opening of the hole 41, and the hole 33b is connected to the lower end opening of the hole 42. The groove portion 32 of the first silicone member 30 is closed by the second silicone member 40. For example, the sample liquid is injected from the hole 41, flows through the groove 32, and is taken out from the hole 42.

Next, the effects of the silicone member of this embodiment will be explained. The silicone member of this embodiment and the silicone member of the first embodiment have similar functions and effects regarding parts having common configurations. Since the first silicone member 30 and the second silicone member 40 have the same hydrophilic layer, the first silicone member 30 will be described here as a representative of both members.

The housing portion 31 of the first silicone member 30 has a hydrophilic layer 35 made of PVA. PVA is bonded to the silicone body 34 through chemical bonds between hydroxyl groups, and has a long molecular chain containing a hydrophilic structure. Due to the steric hindrance of the long molecular chains, even when the silicone molecular skeleton rotates, the hydrophilic structure is difficult to penetrate inside. Therefore, in the first silicone member 30, the hydrophilicity of the hydrophilic layer 35 continues for a long time. Specifically, as shown in Examples described later, a state in which the water contact angle is 60° or less is maintained for at least 24 hours after the hydrophilic layer 35 is formed.

The type A durometer hardness measured on the upper surface of the first silicone member 30 (the part where the hydrophilic layer 35 is formed) is A60. That is, the hydrophilic layer 35 is more flexible than glass. Therefore, the hydrophilic layer 35 is less likely to crack or peel off, and its hydrophilicity remains for a long time. In this way, the housing part 31 of the first silicone member 30 has a flexible hydrophilic layer 35 that has long hydrophilic properties, so that various operations such as tests and reactions can be performed accurately using a hydrophilic liquid. be able to. In addition, since the hydrophilic layer 35 is thin, it is difficult to inhibit the flow of liquid even when applied to the accommodating portion 31 having a fine channel structure. Because of its good flowability, the pressure during liquid feeding is unlikely to increase. As a result, peeling of the joint portion between the first silicone member 30 and the second silicone member 40 is suppressed.

Even though the hydrophilic layer 35 is formed, the visible light transmittance of the accommodating portion 31 is high, and the inherent transparency of silicone rubber is not impaired. Since the autofluorescence of the housing part 31 is also weak, it is suitable for optical inspection, etc. in which the housing part 31 is irradiated with light and extremely weak luminescence is observed. Furthermore, even if the sample contains protein, the protein is unlikely to be adsorbed to the storage portion 31.

In the method for manufacturing the first silicone member 30, before forming the hydrophilic layer 35, hydroxyl groups are added to the upper surface of the silicone body 34 including the accommodation portion 31 in a modification treatment step. Thereby, in the subsequent hydrophilic layer forming step, the hydrophilic layer 35 can be easily formed by dip coating PVA. Since the viscosity of the PVA aqueous solution is relatively low, a thin hydrophilic layer 35 can be formed. Furthermore, since the solvent of the aqueous solution is water, it is difficult to seep into the hydrophobic silicone body 34. Therefore, during dip coating, there is little risk that the silicone main body 34 will swell and the size of the accommodating portion 31 will change.

The hydrophilic layer 35 is formed on the entire upper surface of the silicone body 34. Similarly, in the second silicone member 40, the hydrophilic layer 45 is formed on the entire lower surface of the silicone body 44. The hydrophilic layers 35 and 45 are both made of PVA and have good adhesive properties. Therefore, the hydrophilic layers 35, 45 can be formed on the joining surfaces of the first silicone member 30 and the second silicone member 40, and can be used to join the two members 30, 40.

<Other forms>
The silicone member and the method for manufacturing the same of the present invention are not limited to the above-mentioned forms, but may be implemented in various forms with changes and improvements that can be made by those skilled in the art without departing from the gist of the present invention. be able to.

[Silicone member]
The silicone member of the present invention is used as a microdevice, and may have an accommodation section in which a sample is accommodated, or may partition the accommodation section by combining with a mating member. The material of the mating member may be silicone, fluororesin, glass, or the like. The silicone member of the present invention and the mating member may be simply laminated, or may be bonded together using an adhesive or the like.

The "accommodating section" in the present invention includes not only a space in which a sample is placed, but also a space such as a channel through which the sample passes. The sample may be a solid such as particles, a liquid, a gas, or a mixture of these as appropriate. The shape, size, and arrangement of the accommodating portion are not particularly limited. Examples of the shape of the accommodating portion include a hole shape, a groove shape, and a depression shape. The cross section of the housing portion in the depth direction is not particularly limited, and may have a rectangular shape such as a square, a rectangle, or a trapezoid, a curved shape such as a semicircle or an ellipse, or a V-shape. Below, an example of a configuration having a housing section different from the above embodiment will be described. FIG. 5 shows a perspective view of the silicone member of the third embodiment. In FIG. 5, the transparent parts are indicated by thin lines.

As shown in FIG. 5, the silicone member 50 has a rectangular thin plate shape. A plurality of wells (recesses) 51 are formed in the upper surface of the silicone member 50 . The opening of the well 51 has a circular shape, and the bottom has a flat shape. The opening of the well 51 has a diameter of 100 μm and a depth of 100 μm. The plurality of wells 51 all have the same shape and size. The sample is accommodated in the well 51. That is, the well 51 is included in the concept of a housing section in the present invention. A hydrophilic layer (not shown) is formed to cover the entire upper surface of the silicone body including the wells 51.

The depth of the accommodating portion may be appropriately determined depending on the thickness of the silicone member and the microdevice. For example, in the case of a microdevice for optical inspection using a microscope, the depth of the housing portion is preferably 100 μm or less. Furthermore, when the accommodating portion has a groove-like channel, it is desirable that the width of the channel is also 100 μm or less.

The accommodating part has a silicone main body and a hydrophilic layer. The silicone body is manufactured from a silicone material with silicone. The silicone material may contain additives such as adhesive components, if necessary. In this specification, "silicone" is a concept that includes both silicone resin and silicone rubber. In addition to the polymer component, "silicone" includes a crosslinking agent, a catalyst, etc. for crosslinking the polymer component. As the silicone rubber, one that is widely known as organopolysiloxane may be used. The silicone rubber may be a liquid rubber or a solid (millable) rubber. Liquid rubber is desirable in that it can form microstructures such as unevenness with high dimensional accuracy.

The hydrophilic layer is made of a hydrophilic polymer having a hydrophilic structure and a hydroxyl group chemically bonded to the silicone body. Examples of the hydrophilic structure include nonionic structures such as hydroxyl groups and polyether structures, cationic structures such as amines and ammonium salts, and anionic structures such as phosphates, sulfonates, and carboxyl groups. It is desirable that the hydrophilic polymer has at least one type selected from these. From the viewpoint of increasing the steric hindrance of the molecular chain and suppressing the hydrophilic structure from penetrating into the silicone due to rotation of the molecular skeleton, it is desirable that the molecular chain containing the hydrophilic structure is long. For example, the weight average molecular weight of the hydrophilic polymer is preferably 500 or more. More preferably, it is 5,000 or more, 10,000 or more, and even 20,000 or more.

Examples of the form of the hydroxyl group that chemically bonds with the silicone body include Si-OH, which forms a Si-O-Si bond with the silicone body, and C-OH, which forms a Si-O-C bond. It is desirable that the hydrophilic polymer has either or both of these. From the viewpoint of increasing the number of bonding sites with the silicone body and suppressing the hydrophilic structure from penetrating into the interior due to rotation of the molecular skeleton of the silicone, hydrophilic polymers have two or more hydroxyl groups that chemically bond with the silicone body. It is desirable to have one. Suitable hydrophilic polymers include polyvinyl alcohol, partially saponified polyvinyl acetate, vinyl alcohol-sodium acrylate copolymer, vinyl alcohol-sodium methacrylate copolymer, partially cross-linked sodium polyacrylate, polyethylene glycol, polyethylene glycol derivatives, alkoxysilyl Examples include group-containing polymers, cellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, starch, and the like. Among these, polyvinyl alcohol, polyethylene glycol, and alkoxysilyl group-containing polymers are preferred because they are relatively inexpensive and have excellent biocompatibility.

In the silicone member of the present invention, the hydrophilicity of the hydrophilic layer lasts for a long time. For example, after the hydrophilic layer is formed, it is desirable that the contact angle of water is maintained at 60° or less for 24 hours or more. It is more preferable to maintain the temperature for 48 hours, 72 hours, or even permanently. In the present invention, a value measured according to JIS R3257:1999 is employed as the contact angle of water.

The thickness of the hydrophilic layer is desirably less than 1 μm from the viewpoint that even when applied to a containing part having a fine structure, the fluid flow is not easily inhibited and the transparency of the silicone body is not easily inhibited. More preferably, it is 0.5 μm or less.

From the viewpoint of ensuring desired light transmittance, it is desirable that the visible light transmittance of the accommodating portion be 80% or more. More preferably, it is 85% or more. In the present invention, as the visible light transmittance, a value calculated by measuring the transmission spectrum in the wavelength range of 380 to 780 nm with a spectrophotometer "UV3100PC" manufactured by Shimadzu Corporation is adopted in accordance with JIS A5759:2016. . In addition, when used for optical inspection etc. in which the housing part is irradiated with light and extremely weak luminescence is observed, the intensity of the autofluorescence of the housing part when irradiated with excitation light with a wavelength of 280 nm or more and 600 nm or less is , 20 or less. More preferably, it is 10 or less. In the present invention, the intensity of autofluorescence is determined by irradiating excitation light with a wavelength of 280 nm or more and 600 nm or less using a spectrofluorometer "F-7000SP" manufactured by Hitachi High-Technologies Corporation, and detecting a wavelength of 300 nm or more and 900 nm. The fluorescence intensity of From the viewpoint of increasing followability to the silicone body and improving adhesion, it is desirable that the type A durometer hardness measured at the portion where the hydrophilic layer is formed is A20 or more and A80 or less. In the present invention, a value measured according to JIS K6253-3:2012 is used as the type A durometer hardness.

[Method for manufacturing silicone members]
The method for manufacturing the silicone member of the present invention is not particularly limited. For example, a hydrophilic layer may be formed by modifying the surface of the accommodating portion of the silicone main body to impart hydroxyl groups to the surface, and then contacting the surface with a polymer solution containing a hydrophilic polymer. In order to bring the polymer solution into contact with the accommodating part, the polymer solution may be applied or poured onto the accommodating part, or the surface including the accommodating part may be immersed in the polymer solution. In this case, if the silicone body is slightly impregnated with the polymer solution, the adhesion of the formed hydrophilic layer can be improved.

As in the second embodiment, when two silicone members are bonded to form a microdevice, if a hydrophilic layer made of a hydrophilic polymer with poor adhesiveness is formed on one surface of the silicone body, the silicone members may Joining becomes difficult. It is also possible to use adhesive or the like to join two silicone members, but in order to seal the housing part, the adhesive must be applied to the boundary with the housing part. may be contaminated by adhesive. Therefore, when forming a hydrophilic layer from a hydrophilic polymer with poor adhesiveness, it is desirable not to form the hydrophilic layer on the joint portion, but to form the hydrophilic layer only on the accommodating portion. On the other hand, in the case where the hydrophilic layer is formed from a hydrophilic polymer that has no problems with adhesion, bondability is unlikely to be inhibited even if the hydrophilic layer is formed in a region other than the accommodating part. A method for manufacturing a silicone member of the present invention will be described below as an example of a method for manufacturing a hydrophilic layer on one surface of a silicone body including a housing portion. The method for manufacturing a silicone member of the present invention includes a modification treatment step and a hydrophilic layer formation step.

(1) Modification treatment step In this step, one surface of the silicone main body on the side that has the accommodation portion or forms the partition is subjected to modification treatment to impart hydroxyl groups to the one surface. The modification treatment may be performed by plasma irradiation, excimer light irradiation, ultraviolet irradiation, application of a silane coupling agent, etc. under atmospheric pressure or vacuum. When employing plasma irradiation, the method of generating plasma is not particularly limited. For example, RF plasma using a radio frequency (RF) power source, microwave plasma using a microwave power source, etc. may be used. Plasma irradiation is preferably performed in a rare gas atmosphere such as argon or in a gas atmosphere containing oxygen.

(2) Hydrophilic layer formation step In this step, a polymer solution containing a hydrophilic polymer is brought into contact with the modified surface to chemically bond the hydroxyl groups of the silicone body and the hydroxyl groups of the hydrophilic polymer. A hydrophilic layer is formed on the one surface including the part. The hydrophilic polymer is as described above. The solvent for the polymer solution may be appropriately selected depending on the hydrophilic polymer. From the viewpoint of suppressing seepage into the silicone body and suppressing swelling of the silicone body, water, alcohol, etc. are suitable. The viscosity of the polymer solution is not particularly limited, but from the viewpoint of forming a thin hydrophilic layer, it is preferably 0.01 Pa·s or more and 20 Pa·s or less. To bring the polymer solution into contact with one side of the silicone body, the polymer solution may be applied to one side, flowed, or one side or the entire silicone body may be immersed in the polymer solution. After contacting with the polymer solution, a drying process is performed to chemically bond the hydroxyl groups of the silicone body and the hydroxyl groups of the hydrophilic polymer. In the drying process, the temperature, time, etc. may be adjusted as appropriate depending on the solvent of the polymer solution.

Next, the present invention will be described in more detail with reference to Examples. Test pieces of silicone members that had been subjected to various hydrophilic treatments were manufactured, and the durability of hydrophilicity was evaluated.

<Manufacture of test piece>
[Example 1]
First, the entire upper surface of a silicone rubber plate-shaped specimen was subjected to a modification treatment to impart hydroxyl groups to the upper surface of the specimen. As the modification treatment, vacuum microwave plasma treatment was performed in which microwave plasma was irradiated under vacuum. The vacuum microwave plasma treatment was performed in an atmosphere of 60 cc/min of argon gas and 300 cc/min of oxygen gas and a pressure of 52 Pa, with a microwave frequency of 2.45 GHz and an output power of 1.2 kW. The processing time was 2 seconds. Next, the test piece after the modification treatment was immersed in an aqueous solution of an alkoxysilyl group-containing polymer (“LAMBIC-771W” manufactured by Osaka Organic Chemical Industry Co., Ltd., viscosity 10 mPa・s), pulled out, and heated at 100°C. By drying for 15 minutes, a 100 nm thick hydrophilic layer made of an alkoxysilyl group-containing polymer was formed on the upper surface. The test piece thus obtained is referred to as the test piece of Example 1.

[Example 2]
A test piece modified in the same manner as in Example 1 was immersed in an aqueous solution (viscosity 7 Pa·s) of PVA (mass average molecular weight 20,000), pulled up, and dried at 100°C for 15 minutes to form PVA on the upper surface. A hydrophilic layer with a thickness of 100 nm was formed. As the PVA aqueous solution, an aqueous solution containing 1 g of PVA mixed with 100 g of pure water was used. The obtained test piece is referred to as the test piece of Example 2.

[Example 3]
A test piece modified in the same manner as in Example 1 was immersed in an aqueous solution (viscosity 7 Pa s) of polyethylene glycol (PEG: mass average molecular weight 6000), then pulled up and dried at 100°C for 15 minutes. A 100 nm thick hydrophilic layer made of PEG was formed on the top surface. As the PEG aqueous solution, an aqueous solution containing 1 g of PEG in 100 g of pure water was used. The obtained test piece is referred to as the test piece of Example 3.

[Example 4]
A test piece was produced in the same manner as in Example 3, except that the PEG aqueous solution used in Example 3 was changed to an aqueous solution (viscosity 10 Pa·s) containing 5 g of PEG in 100 g of pure water. The obtained test piece is referred to as the test piece of Example 4.

[Comparative example 1]
A test piece was produced in the same manner as in Example 1, except that the upper surface of the test piece was not modified before forming the hydrophilic layer. The obtained test piece is referred to as a test piece of Comparative Example 1.

[Comparative example 2]
A test piece was produced in the same manner as in Example 2, except that the upper surface of the test piece was not modified before forming the hydrophilic layer. The obtained test piece is referred to as a test piece of Comparative Example 2.

[Comparative example 3]
A test piece made of silicone rubber that was not treated with anything was referred to as a test piece of Comparative Example 3.

[Comparative example 4]
The upper surface of the silicone rubber test piece was subjected to hydrophilic treatment by irradiating ultraviolet rays at an irradiation distance of 1 mm for 300 seconds using an ultraviolet cleaning and reforming device manufactured by Sen Tokushu Light Source Co., Ltd. The obtained test piece is referred to as a test piece of Comparative Example 4.

[Comparative example 5]
The top surface of the silicone rubber test piece was subjected to hydrophilic treatment by irradiating excimer light with an excimer lamp light source "EX-mini" manufactured by Hamamatsu Photonics Co., Ltd. at an irradiation distance of 1 mm for 120 seconds. The obtained test piece is referred to as a test piece of Comparative Example 5.

[Comparative example 6]
The upper surface of a silicone rubber test piece was irradiated with microwave plasma under vacuum to perform a hydrophilic treatment. The vacuum microwave plasma treatment was performed in an atmosphere of 90 cc/min of argon gas and 90 cc/min of oxygen gas and a pressure of 6 Pa, with a microwave frequency of 2.45 GHz and an output power of 0.75 kW. The processing time was 2 seconds. The obtained test piece is referred to as a test piece of Comparative Example 6.

[Comparative Example 7]
A hexamethyldisiloxane (HMDSO) film was formed on the upper surface of a silicone rubber test piece by plasma CVD to perform a hydrophilic treatment. The plasma treatment was performed in an atmosphere of 180 cc/min of oxygen gas and 12 cc/min of HMDSO gas and a pressure of 6.4 Pa, with a microwave frequency of 2.45 GHz and an output power of 0.75 kW. The thickness of the HMDSO film was 30 nm. The obtained test piece is referred to as a test piece of Comparative Example 7.

<Evaluation method>
[Hydrophilicity]
Water contact angle was measured according to JIS R3257:1999. In this example, 2 μl of water was dropped onto the surface of the object to be measured in an atmosphere at a temperature of 25° C. and a humidity of 50%, and the water contact angle was measured within 1 minute after the water came into contact with the surface.

[Optical transparency]
According to JIS A5759:2016, the transmission spectrum was measured using a spectrophotometer "UV3100PC" manufactured by Shimadzu Corporation, and the visible light transmittance of the test piece was calculated.

[Autofluorescence]
Using the spectrofluorometer "F-7000SP" manufactured by Hitachi High-Technologies Corporation, the detection light (fluorescence) is measured by irradiating excitation light with a wavelength of 280 nm or more and 600 nm or less, and the fluorescence intensity with a wavelength of 300 nm or more and 900 nm is measured as autofluorescence. The strength of

[Type A durometer hardness]
Type A durometer hardness was measured according to JIS K6253-3:2012.

Table 1 shows the evaluation results of each test piece. FIG. 6 shows the change over time in the water contact angle of the test pieces of Example 1 and Comparative Examples 1 and 7. FIG. 7 shows changes over time in the water contact angle of the test pieces of Example 2 and Comparative Example 2. FIG. 8 shows the change over time in the water contact angle of the test pieces of Examples 3 and 4. FIG. 9 shows the changes over time in the water contact angle of the test pieces of Comparative Examples 4 to 6. For reference, the graphs in FIGS. 6 to 9 show the water contact angle of the test piece of Comparative Example 3 (untreated) as the value at an elapsed time of 0 hours.

As shown in Table 1 and FIGS. 6 to 8, in the test pieces of Examples 1 to 4 in which a hydrophilic layer was formed after the modification treatment, not only 24 hours after the formation of the hydrophilic layer but also 168 hours (7 Even after several days), the water contact angle was 60° or less, and hydrophilicity was maintained. In particular, the test pieces of Examples 1, 2, and 4 were excellent in hydrophilicity, and when comparing the water contact angles for 7 days after forming the hydrophilic layer, the test pieces of Example 1 were 15 or less, and the water contact angles of Example 2 were 15 or less. , 4 test pieces had a score of 30 or less. In the test pieces of Examples 1 to 4, the visible light transmittance was 87% or more, and it was confirmed that the hydrophilic layer had excellent light transmittance. It was also confirmed that autofluorescence was weak. Furthermore, in the test pieces of Examples 1 to 4, the Type A durometer values were relatively small, which confirmed that the hydrophilic layer was relatively flexible. On the other hand, in the test piece of Comparative Example 1 in which a hydrophilic layer was formed without any modification treatment, the water contact angle exceeded 60° 24 hours after the formation of the hydrophilic layer. In the test piece No. 2, the water contact angle became larger than 60° immediately after forming the hydrophilic layer. It is thought that in these cases, since there was no hydroxyl group on the silicone rubber side, the hydrophilic polymer was not chemically bonded and the hydrophilicity did not last. Also, in the test piece of Comparative Example 7 in which the HMDSO film was formed, the water contact angle became larger than 60° immediately after forming the hydrophilic layer (see FIG. 6). Further, as shown in Table 1 and FIG. 9, it can be seen that the duration of hydrophilicity is short in all of the test pieces of Comparative Examples 4 to 6 that were subjected to conventional hydrophilic treatment.

10: Silicone member, 11: Accommodating part, 12: Groove, 13a, 13b: Hole, 14: Silicone body, 15: Hydrophilic layer, 20: Micro device, 30: First silicone member, 31: Accommodating part, 32: Groove, 33a, 33b: Hole, 34: Silicone main body, 35: Hydrophilic layer, 40: Second silicone member, 41, 42: Hole, 43: Accommodating part, 44: Silicone main body, 45: Hydrophilic layer, 50: Silicone member, 51: Well (accommodating part).

Claims (12)

A silicone member that is used as a microdevice and has a housing section in which a sample is housed, or that partitions the housing section by combining with a mating member,
The accommodating portion has a silicone body and a hydrophilic layer disposed on the surface of the silicone body,
The hydrophilic layer is made of a hydrophilic polymer having a hydrophilic structure and two or more hydroxyl groups chemically bonded to the silicone body,
The weight average molecular weight of the hydrophilic polymer is 5000 or more,
The hydrophilic structure is one or more selected from a hydroxyl group, a polyether structure, and a carboxyl group,
The hydroxyl group that chemically bonds with the silicone body is at least one of Si-OH that forms a Si-O-Si bond with the silicone body, and C-OH that forms a Si-O-C bond with the silicone body, A silicone member characterized in that the hydrophilic layer is fixed to the silicone body by chemical bonding by the hydroxyl groups. The silicone member according to claim 1, wherein the thickness of the hydrophilic layer is less than 1 μm. The silicone member according to claim 1 or 2, wherein the depth of the accommodating portion is 100 μm or less. The accommodating portion has a groove-like flow path,
The silicone member according to any one of claims 1 to 3, wherein the width of the channel is 100 μm or less. The silicone member according to any one of claims 1 to 4, wherein the visible light transmittance of the accommodating portion is 80% or more. The silicone member according to any one of claims 1 to 5, wherein the intensity of autofluorescence of the housing section is 20 or less when irradiated with excitation light having a wavelength of 280 nm or more and 600 nm or less. 7. The silicone member according to claim 1, wherein the type A durometer hardness measured at the portion where the hydrophilic layer is formed is A20 or more and A80 or less. The silicone member according to any one of claims 1 to 7, wherein the hydrophilic polymer is one or more selected from polyvinyl alcohol, polyethylene glycol, polyethylene glycol derivatives, cellulose, carboxymethyl cellulose, and partially crosslinked sodium polyacrylate. . 9. The silicone member according to claim 1, wherein the hydrophilic layer maintains a water contact angle of 60° or less for 24 hours or more. A method for manufacturing a silicone member according to any one of claims 1 to 9 , comprising:
a modification treatment step of modifying one side of the silicone body on the side that has the accommodation portion or forms the partition, and imparting hydroxyl groups to the one side;
Forming a hydrophilic layer by contacting the one surface with a polymer solution containing the hydrophilic polymer to chemically bond the hydroxyl groups of the silicone body and the hydroxyl groups of the hydrophilic polymer to form the hydrophilic layer on the one surface. process and
A method for manufacturing a silicone member, comprising: The method for manufacturing a silicone member according to claim 10 , wherein the viscosity of the polymer solution is 0.01 Pa·s or more and 20 Pa·s or less. The method for manufacturing a silicone member according to claim 10 or 11 , wherein the solvent of the polymer solution is water or alcohol.

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