JP2016050912A - Paper substrate device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new paper substrate device and a manufacturing method of it that can perform an analysis or reaction without requiring much sample solution and can be produced easily without using UV irradiation, heating, titanium dioxide particles, or the like.SOLUTION: The paper substrate device includes: a paper substrate; a hydrophobic silane coupling agent that is applied onto the paper substrate and has a specific structure; and a flow channel with a desired shape formed of a hydrophilic silane coupling agent that is applied in the region coated with the hydrophobic silane coupling agent and has a specific structure.SELECTED DRAWING: Figure 1

Description

  The present invention is a paper substrate device (also referred to as “paper substrate microfluidic devices” (μPADs), “paper-based reaction chips”, etc.) used for various chemical analyzes and chemical reactions, and the like. It relates to the manufacturing method.

  Paper-based devices are devices that use flow paths on paper to perform analysis, chemical reactions, etc., and because they are paper-based, they can be easily carried and discarded, and can be analyzed with a small amount of sample. Has attracted attention in recent years. Paper substrate devices developed to date include: (1) Print ink on the filter paper that is cured by UV irradiation using an inkjet printer in the form of a flow path, irradiate UV, and apply it to the front and back Thus, a method of forming a flow path by constructing a hydrophobic wall only at the place of printing (Patent Document 1, Non-Patent Document 1), (2) Creating a hydrophobic wall using trimethoxyoctadecylsilane and heat A method for producing a channel (Non-patent Document 2), (3) The channel is made hydrophobic by spraying titanium dioxide particles onto a paper substrate and hydrophobizing it selectively by irradiating ultraviolet rays. And a method for producing a spot portion (Non-patent Document 3) is known.

  The method described in Patent Document 1 has an advantage that a flow path having an arbitrary shape can be easily produced by an ink jet printer, but UV irradiation is required, and the sample liquid moves through the filter paper by capillary action. The moving speed is low, the sample liquid evaporates during the movement, and a relatively large amount of the sample liquid is required due to the infiltration of the sample liquid into the filter paper. In the method described in Non-Patent Document 2, heating is necessary, and a filter paper substrate is used, so that there are problems similar to the method described in Patent Document 1. The method described in Non-Patent Document 3 has the advantage that a large amount of sample liquid is not necessary because it does not use capillary action for the movement of the sample liquid, but it is necessary to spray titanium dioxide particles and UV irradiation is also necessary. .

WO 2012/160857 A1

Kento Maejimaet.al., RSC Adv., 2013,3, 9258-9263 Longfei Cai et.al., Analyst, 2014, 139, 4593-4598 Aritra Ghosh et.al., Lab Chip, 2014, 14, 1538

  An object of the present invention is to provide a novel paper base material that can be analyzed and reacted without requiring a large amount of sample solution, and can be easily produced without using UV irradiation, heating, titanium dioxide particles, etc. It is to provide a device and a manufacturing method thereof.

  As a result of diligent research, the inventors of the present invention coat a hydrophobic silane coupling agent on the surface of the substrate, and selectively coat a hydrophilic silane coupling agent thereon to form a flow path. As a result, the sample liquid can be moved quickly without using the capillary action in the paper substrate, thereby reducing the required amount of the sample liquid, and the flow path can be easily controlled by an ink jet printer. The present invention was completed by discovering that a device can be easily produced without requiring UV irradiation, heating, titanium dioxide particles and the like.

That is, the present invention
A paper substrate;
The general formula [I] coated on the paper substrate:

(In the formula [I], R ¹ is an alkyl group having 6 or more carbon atoms, an alkenyl group having 6 or more carbon atoms, or an aryl group or an alkylaryl group, R ² , R ³ and R ⁴ in the hydrophobic side chain, independently of each other. Represents an alkyl group having 1 to 4 carbon atoms)
A compound represented by
The general formula [II] coated in the area coated with the compound:

(In the formula [II], R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent an alkyl group having 1 or 2 carbon atoms)
And a paper substrate device having a flow path of a desired shape formed from a compound represented by the formula:

  The present invention also includes a step of coating a paper substrate with a solution of the compound represented by the general formula [I] and drying, and a solution of the compound represented by the general formula [II] in the coated region. A method for producing the paper substrate device of the present invention, comprising the step of coating the substrate with a desired shape and drying.

  According to the present invention, capillary action is not used for movement of the sample liquid, and therefore analysis and reaction can be performed without requiring a large amount of sample liquid, and UV irradiation, heating, titanium dioxide particles, etc. are used. For the first time, a novel paper substrate device and a method for producing the same were provided. If the paper base device of the present invention is used, a necessary amount of a valuable sample solution can be reduced as compared with the case where a known paper base device using a capillary phenomenon is used. Also, the paper base device of the present invention can be easily and inexpensively manufactured, and if a commercially available inexpensive copy paper or the like is used as the base material, the manufacturing cost can be greatly reduced.

It is a figure which shows the shape and dimension of the flow path of the paper base material device produced in the following Example. It is a figure which shows the relationship between the ferrous ion density | concentration in a sample, and the difference of Green intensity | strength measured in the following Example.

  As described above, the paper substrate device of the present invention includes a paper substrate. Any paper can be used as the paper substrate, and copy paper, filter paper, and the like can be used. As with the prior art, filter paper can be used. However, it is advantageous in terms of cost to use copy paper that is less expensive than filter paper, and copy paper is also used in the following embodiments.

On the paper substrate, the compound represented by the above general formula [I] is coated. In the general formula [I], R ¹ represents a hydrophobic side chain alkyl group having 6 or more carbon atoms, an alkenyl group having 6 or more carbon atoms, an aryl group, or an alkylaryl group. These impart hydrophobicity, and the upper limit of the carbon number of the alkyl group or alkenyl group is not particularly limited, but the upper limit of the carbon number is usually about 30. In the case of an alkyl group or an alkenyl group, the carbon number is preferably 15 to 25, and particularly 16 to 20. In the following examples, an octadecyl group having 18 carbon atoms is used. Preferred examples of the aryl group include benzene and naphthalene. The aryl group in the alkylaryl group is preferably benzene or naphthalene, and the carbon number of the alkyl moiety in the alkylaryl group is not particularly limited, and is usually 1-30.

In the above general formula [I], R ² , R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, preferably all ethyl groups.

  Coating of the compound represented by the general formula [I] can be performed by coating a solution of the compound on a paper substrate and drying. The solvent is not particularly limited as long as it can dissolve the compound, and it is preferable to use a lower alcohol (preferably having 1 to 4 carbon atoms) such as isopropanol which is easily available and has relatively little adverse effect on the human body. it can. The solution may be coated on the entire surface of the paper substrate, or may be coated only on a partial region, but it is convenient to coat the entire surface. The coating may be performed by any method such as dipping, spray coating, roll coating, etc., but dipping is preferable because the operation is simple and the hydrophobicity of the paper substrate becomes greater when the same solution is used. By immersing the entire paper substrate in the solution, the entire surface of both sides of the paper substrate is coated. After coating, the compound represented by the above general formula [I] is coated on a paper substrate by drying the solution and evaporating the solvent. Drying can be easily performed by leaving it to stand at room temperature. The drying time is usually about 12 hours to 48 hours, preferably about 18 hours to 30 hours, and may be dried for longer than 48 hours. By coating the compound represented by the general formula [I], the paper substrate is hydrophobized.

A partial region on the coated layer of the compound represented by the general formula [I] is selectively coated with the compound represented by the general formula [II] constituting the flow path. In the general formula [II], R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group having 1 or 2 carbon atoms, and a lower alkoxyl having 1 or 2 carbon atoms bonded to a Si atom. Hydrophilicity is imparted by the group.

  The coating of the compound represented by the general formula [II] is performed by selectively applying a solution of the compound represented by the general formula [II] on the layer of the compound represented by the general formula [I]. It can be done by coating and drying. The solvent of the solution is not particularly limited as long as it can dissolve the compound represented by the general formula [II]. Preferably, water or an aqueous solution of a weak acid or a weak base is used. For example, acetic acid having a pH of about 3 to 5 is used. An aqueous solution can be used. In order to make it easy to eject ink with an ink jet printer, a trace amount of surfactant may be included. As the surfactant, for example, a nonionic surfactant such as Triton X-100 (trade name) can be preferably used, but is not limited thereto. The concentration of the surfactant can be appropriately set, and is usually about 0.01% by weight to 0.05% by weight. The concentration of the compound in the solution is not particularly limited, but is usually about 0.1 to 10 v / v%, preferably about 0.5 to 2 v / v%.

  The coating method of the solution of the compound represented by the general formula [II] is not particularly limited, but the solution is used as an ink for an ink jet printer, and it is most convenient to print a flow path prepared using a personal computer software. A complicatedly shaped channel is also preferable because it can be drawn easily. Here, the “flow channel” is used to include not only the passage through which the sample solution or the like flows but also all the regions that are intended to get wet with the sample solution or the like. Or a spot portion having a width wider than the passage, which causes a desired chemical reaction. For example, in the following embodiment, the shape shown in FIG. 1 is drawn by an ink jet printer, but square portions at both ends in FIG. 1 are also included in the “flow path” referred to in the present invention. However, it is also possible to form only a part of the channel with the compound represented by the general formula [II]. The paper substrate device of the present invention can be obtained by printing the flow path with an ink jet printer and then drying it. Drying can be easily performed by leaving it to stand at room temperature. The drying time is usually about 5 to 120 minutes, preferably about 20 to 60 minutes, and may be dried longer than 120 minutes.

The microchannel itself is well known, and an arbitrary analysis and reaction can be performed by drawing a channel having an arbitrary shape. Compounds for analysis and reaction can be immobilized on the spot portion of the channel. Reagents necessary for analysis and reaction can be further printed on the flow path by an ink jet printer after forming the flow path with the compound represented by the general formula [II]. In this case, when the compound of general formula [II] and the reagent have low affinity and are difficult to be immobilized, the compound of general formula [II] has high affinity, preferably general formula [II A compound obtained by combining a compound of the above formula, a silane coupling substance and a reagent can be printed by an ink jet printer. Examples of the substance suitable for binding to the reagent and having a high affinity with the compound represented by the general formula [II] include any of R ⁵ , R ⁶ , R ⁷ and R ^{8 in} the general formula [II]. Examples thereof include those having a functional group such as an amino group or a carboxyl group introduced therein. In the following examples, 3-aminopropyltriethoxysilane (APTES) and ferrozine, which is a Fe ²⁺ detection reagent, are ion-bonded in a solution and printed on the spot portion of the flow path by using an inkjet printer. Thus, ferrozine is immobilized.

  Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to the following examples.

Example 1 Fabrication of a paper substrate device OTES (octadecyltriethoxysilane) solution As the compound represented by the above general formula [I], octadecyltriethoxysilane (OTES, in general formula [I], R ¹ is an octadecyl group (carbon number 18), R ² , R ³ And R ⁴ are all ethyl groups). A 1 v / v% isopropanol solution of OTES was prepared.

2. TMOS (tetramethylorthosilicate) ink As a compound represented by the above general formula [II], tetramethylorthosilicate (TMOS, in general formula [I], R ⁵ , R ⁶ , R ⁷ and R ⁸ are all methyl groups) Was used. The TMOS ink was prepared according to the following procedure.

(1) A 0.02 wt% TritonX-100 (trade name, surfactant) aqueous solution was prepared using water (milli-Q (trade name)) as a solvent. 50 mL of this was taken with Pipetteman (trade name), and an acetic acid solution added with 2 μL of acetic acid was used as the solvent of the ink used this time. The pH was 3.92.
(2) 4.5 mL of an acetic acid-TritonX-100 (trade name) aqueous solution was taken using a pipetteman (trade name) on the screw tube.
(3) While stirring (2) with a magnetic stirrer, 0.5 mL of TMOS taken with the same Pipetteman (trade name) was added dropwise to make TMOS 10% (v / v) ink.
Hereinafter, the ink prepared here is referred to as TMOS ink.

3. Flow path preparation The copy paper was immersed in the OTES solution prepared in 1, and dried at room temperature for 24 hours. The contact angle of the copy paper with respect to water was 77 °, which was hydrophilic (the contact angle with respect to water was less than 90 °), but after OTES coating, it became 120 ° and became hydrophobic.

  Next, using a commercially available inkjet printer (FUJIFILM Dimatix DMP-2831, ink cartridge DMC-11610 with a droplet volume of 10pL), print the TMOS ink prepared in 2 on the copy paper coated with OTES. did. The printed flow path has the shape and dimensions shown in FIG. 1, and printing was performed twice in the same place. The paper substrate device of the present invention was obtained by drying at room temperature for 20 minutes.

Example 2 Measurement of Flow Rate The flow rate when an aqueous dye solution was allowed to flow through the flow path of the device produced in Example 1 was measured. 1 μL of the red food solution was dropped on the square part at one end of the flow channel shown in FIG. 1 and the time until it reached the square part at the other end was visually measured. The measurement was performed 35 times. On the other hand, for comparison, flow paths having the same shape and size were produced on a filter paper substrate by the method described in Patent Document 1, and the flow velocity was measured in the same manner.

  As a result, in the flow path of the device of the present invention produced in Example 1, the average flow velocity was 1.1 mm / s, whereas in the flow path of the device described in Patent Document 1, it was 0.2 mm / s. When the inventive device was used, a flow rate of 5 times or more was observed. As a result of observation, the dripped aqueous solution seems to travel along the hydrophilic flow path with the momentum at the time of dripping as the driving force, and the aqueous solution does not soak into the copy paper at all and moves by capillary action. is not.

Example 3 Detection of Fe ²⁺ Using the device prepared in Example 1, an Fe ²⁺ detection test was performed. As a Fe ²⁺ detection reagent, ferrozine (3- (2-pyridyl) -5,6-bis (4-sulfophenyl) -1,2,4-triazine disodium salt, PTDS) (pKa: 3.2) Using. PTDS reacts with Fe ²⁺ at pH 3-10 to form a red purple chelate. The detection reagent was stacked in a square shape with a side of 1 mm in a square part at one end of the flow path by printing with an inkjet printer. Since PTDS alone is difficult to immobilize in a hydrophilic flow path, 3-aminopropyltriethoxysilane (APTES, pKb: 3.6) that couples TMOS with silane is brought into contact with PTDS in solution to form an ionic bond. Was fixed by printing with an inkjet printer. PTDS and APTES are considered to be ionically bonded as follows in the solution.

  That is, a 1 mM PDTS solution was prepared using pH 3.2 buffer (citric acid 0.1 M, ascorbic acid 25 mM / TMAOH 0.1 M) as a solvent. Meanwhile, a 3 mM isopropanol solution of APTES was prepared. Each prepared APTES solution and PDTS solution are mixed at a volume ratio of 1: 1 (molar ratio 3: 1), and this mixed solution is printed in a square shape of 1 mm square at the center of the square at one end of the flow path by the inkjet printer described above. did. Thereby, PDTS was fixed to the square part of the flow path.

Next, prepare ferrous ammonium sulfate ((NH ₄ ) ₂ Fe (SO ₄ ) ₂ ) aqueous solutions with concentrations of 0, 100, 250, 500, and 1000 μM, and add ₃ μL of each to the square part (PTDS The solution was added dropwise to each of the square portions other than the fixed square portion) to cause a color reaction with the immobilized PTDS. After the reaction, the color analysis of the square part where PTDS was immobilized was performed with Image J (trade name), and the strength of Green was measured. Color analysis was performed before and after the sample was dropped, and the difference was calculated. The results are shown in FIG.

As shown in FIG. 2, the difference in Green intensity changes depending on the Fe ²⁺ concentration in the sample solution, and it can be seen that the Fe ²⁺ concentration can be quantified by this method. In addition, when performing the same detection using the device of patent document 1, 20-50 microliters of sample solutions were required. For this reason, if the device of the present invention is used, the required amount of the sample solution can be greatly reduced.

Claims (10)

A paper substrate;
The general formula [I] coated on the paper substrate:
(In the formula [I], R ¹ is an alkyl group having 6 or more carbon atoms or an alkenyl group having 6 or more carbon atoms, or an aryl group or alkylaryl group as a hydrophobic side chain, and R ² , R ³ and R ⁴ are independent of each other. And represents an alkyl group having 1 to 4 carbon atoms)
A compound represented by
The general formula [II] coated in the area coated with the compound:
(In the formula [II], R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent an alkyl group having 1 or 2 carbon atoms)
A paper substrate device comprising a channel having a desired shape formed from a compound represented by The paper substrate device according to claim ¹ , wherein R ¹ in the general formula [I] is an alkyl group having 6 or more carbon atoms. The paper substrate device according to claim 2, wherein R ¹ in the general formula [I] is an alkyl group having 15 to 25 carbon atoms.   The paper substrate device according to claim 1 or 3, wherein the compound represented by the general formula [I] is octadecyltriethoxysilane. Formula [II] in, R ^5, R ^6, a paper substrate device according to any one of claims 1 to 4 R ⁷ and R ⁸ are methyl groups.   The paper substrate device according to claim 1, wherein the paper substrate is made of copy paper.   The paper substrate device according to any one of claims 1 to 6, wherein the compound represented by the general formula [I] is coated on the entire surface of the paper substrate.   A step of coating a paper substrate with a solution of the compound represented by the general formula [I] and drying, and coating the solution of the compound represented by the general formula [II] in a desired shape in the coated region The manufacturing method of the paper base device of any one of Claims 1-7 including the process made to dry.   The method according to claim 8, wherein the compound represented by the general formula [I] is coated by immersing the paper substrate in a solution of the compound.   The method according to claim 7 or 8, wherein the solution of the compound represented by the general formula [II] is drawn in a desired shape by an ink jet printer.