Method for producing mucin gel and use thereof

Abstract

To provide a method for producing a mucin gel that gels mucins together without chemically crosslinking them using a crosslinking agent, the method being able to produce a mucin gel that can be sterilized by UV irradiation; and to provide uses thereof.SOLUTION: Provided is a method for producing a mucin gel, comprising a pH adjustment step for adjusting the pH of a raw material solution containing mucin and boric acid to 7.5 or higher. When the concentration of the mucin contained in the raw material solution is A [w / v%] and the concentration of the boric acid contained in the raw material solution is B [mM], the relationship of formula (1) is satisfied (Ln is the natural logarithm with e as the base): LnB>-0.875A+8.306 (1).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a mucin gel and its use. [Background technology]

[0002] Mucin is a glycoprotein expressed on the surface of mucosal tissues (e.g., eyes, nose, stomach, intestines, etc.) and has effects such as protection from bacteria and viruses, moisture retention, wound healing, and symbiosis with intestinal bacteria. Because mucin gel has the effects of mucin described above, it is expected to be used as an antibacterial agent, antiviral agent, culture substrate, etc.

[0003] Conventionally, most mucin gels have been formed by chemically cross-linking mucin molecules using various cross-linking agents (see, for example, Non-Patent Documents 1 to 4). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Production and Technology, 21(11), 7-8 [Non-Patent Document 2] CJMate, S.Mishra et al., Int.J.Biol.Macromol, 151, 2020, 677-690 [Non-Patent Document 3] K. Joyner et al., Soft Matter, 2019, 15, 9632-9639 [Non-Patent Document 4] EZCasassa et al., J.Chem., 63, 1, 1986, 57-60 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the above-mentioned technologies are useful, there is room for improvement in that (i) mucin may be partially altered by chemical cross-linking using a cross-linking agent, which may affect the inherent properties and functions of mucin, and / or (ii) mucin may be altered by UV (ultraviolet) irradiation for sterilization or disinfection, which may affect the inherent properties and functions of mucin.

[0006] One aspect of the present invention aims to provide a method for producing a mucin gel that gels mucins without chemically cross-linking them using a cross-linking agent, which is capable of producing a mucin gel that can be sterilized by UV irradiation, and uses of the same. [Means for solving the problem]

[0007] One aspect of the present invention includes the following configuration.

[0008] [1] A method for producing a raw material solution containing mucin and boric acid, comprising the steps of: adjusting the pH of the raw material solution to 7.5 or more; A method for producing a mucin gel, which satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), when the concentration of the mucin contained in the raw material solution is A [w / v%] and the concentration of the boric acid contained in the raw material solution is B [mM]: LnB>-0.875A+8.306···(1).

[0009] [2] The method for producing a mucin gel according to [1], wherein the value of A is 3.000 w / v% or more.

[0010] [3] The method for producing a mucin gel according to [1] or [2], wherein the value of B is 1.000 mM or more.

[0011] [4] A mucin gel containing mucin and boric acid and having a pH of 7.5 or higher, A mucin gel that satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), where A is the concentration of the mucin contained in the mucin gel [w / v%] and B is the concentration of the boric acid contained in the mucin gel [mM]: LnB>-0.875A+8.306···(1).

[0012] [5] The mucin gel according to [4], wherein the value of A is 3,000 w / v% or more.

[0013] [6] The mucin gel according to [4] or [5], wherein the value of B is 1.000 mM or more.

[0014] [7] The mucin gel according to any one of [4] to [6], wherein the mucin gel has a loss tangent (tan δ) value of 1.000 or less. (The loss tangent (tan δ) value is the value at an angular frequency of 10 rad / s when viscoelasticity measurement (strain: 10%) was performed.)

[0015] [8] The mucin gel according to any one of [4] to [7], wherein the remaining rate of the complex elastic modulus of the mucin gel before and after UV treatment is 90.0% or more. (The total UV irradiation dose for the mucin gel in the above UV treatment was 900 mW sec / cm 2 (It is.)

[0016] [9] An article comprising the mucin gel according to any one of [4] to [8].

[10] The article according to [9], which is an in vitro evaluation device, a medicine, a quasi-drug, a cosmetic, a substrate, a collection material, a pharmaceutical DDS device, a cryopreservation device, an adhesive, an artificial joint, an eye patch, a bandage, or a napkin. Effect of the Invention

[0017] According to one aspect of the present invention, there is provided a method for producing a mucin gel by gelling mucins without chemically crosslinking them using a crosslinking agent, which is capable of producing a mucin gel that can be sterilized by UV irradiation, and uses thereof. [Brief description of the drawings]

[0018] [Figure 1] 1 is an image of a mucin gel obtained in Example 2 in accordance with the present invention. [Diagram 2] 1 is a graph showing the relationship between the concentration of mucin and the concentration of boric acid contained in a raw material solution in an example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to this, and various modifications are possible within the scope described, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. In addition, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more, B or less."

[0020] <1. Manufacturing method of mucin gel> A method for producing a mucin gel according to one embodiment of the present invention includes a pH adjustment step of adjusting the pH of a raw material solution containing mucin and boric acid to 7.5 or higher, and when the concentration of the mucin contained in the raw material solution is A [w / v %] and the concentration of the boric acid contained in the raw material solution is B [mM], the relationship of formula (1) (Ln is the natural logarithm with e as the base) is satisfied: LnB>-0.875A+8.306···(1).

[0021] Hereinafter, "a method for producing a mucin gel according to one embodiment of the present invention" may be referred to as "the present production method".

[0022] This manufacturing method makes it possible to produce a mucin gel that can be sterilized by UV irradiation, by gelling mucins without chemically crosslinking them with a crosslinking agent. This can contribute to the achievement of the Sustainable Development Goals (SDGs), such as Goal 3 "Ensure healthy lives and promote well-being for all at all ages."

[0023] The mucin gel obtained by this production method is also one embodiment of the present invention. In this specification, "the mucin gel according to one embodiment of the present invention" may be referred to as "the present mucin gel".

[0024] [1-1] Mucin In this specification, "mucin" refers to a glycoprotein having a repeating sequence rich in glycans in the core protein. Mucins are classified into membrane-bound and free types, but the present production method can be applied to both membrane-bound and free types. Most free mucins contain more cysteine ​​than membrane-bound mucins. Free mucins can form bonds with other substances that have various functions via cysteine. From the viewpoint of expanding the applicability of the produced mucin gel, the mucin used in the present production method is preferably free mucin.

[0025] The type of mucin is not particularly limited, but examples thereof include submandibular mucin, sublingual mucin, intestinal mucin, etc. The above mucins may be used alone or in combination of two or more kinds.

[0026] Examples of free mucins include MUC2, MUC5AC, MUC5B, MUC6, MUC7, MUC9, and MUC19. Examples of membrane-bound mucins include MUC1, MUC3, MUC4, MUC12, MUC13, MUC15, MUC16, MUC17, and MUC20.

[0027] The mucin may be derived from an animal or another organism. Examples of the animals and organisms include primates such as humans, monkeys, and chimpanzees; mammals such as cows, pigs, sheep, goats, horses, dogs, cats, rabbits, mice, and rats; fish such as eels, loaches, catfish, conger eels, pufferfish, and parrotfish; mollusks such as squids, turban shells, and snails; and marine organisms such as jellyfish.

[0028] In this specification, "mucin" may include not only mucin but also mucin-like substances. Therefore, the raw material solution may contain mucin (mucin and / or mucin-like substances). The mucin-like substances are glycoproteins derived from plants. Examples of the mucin-like substances include plant viscous components (e.g., mucilage, etc.) from okra, yam, mushrooms, etc.

[0029] Other substances that form bonds with mucin are not limited and may be appropriately selected depending on the desired effect of the mucin gel. Examples of such other substances include antibiotics, antibacterial substances, anti-inflammatory substances, steroids, immunosuppressants, cell growth factors, cell scaffolding molecules, antiviral agents, enzyme inhibitors, metal chelating agents, bacterial colonization factors, and viral adhesion factors.

[0030] [1-2] Boric acid In this specification, the term "boric acid" refers to an inorganic acid containing boron. By using boric acid in this production method, mucins can be gelled without chemically crosslinking them with a crosslinking agent, and the resulting mucin gel can be sterilized by UV irradiation.

[0031] The boric acid is not particularly limited, but may be, for example, a borate ion (including those derived from ortho-meta-tetraboric acid and their salts, and those derived from diboric acid trioxide). The boric acid may be used alone or in combination of two or more kinds.

[0032] [1-3] Raw material solution In this specification, the term "raw material solution" refers to a mixed solution containing mucin and boric acid.

[0033] In the present production method, the concentration of mucin contained in the raw material solution is not particularly limited as long as it satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), where A is the concentration of mucin contained in the raw material solution [w / v %] and B is the concentration of boric acid contained in the raw material solution [mM]: LnB>-0.875A+8.306···(1).

[0034] The concentration of the mucin contained in the raw material solution is preferably 3.000 w / v% or more, may be 6.000 w / v% or more, 7.000 w / v% or more, 8.000 w / v% or more, or may be 10.000 w / v% or more. The upper limit of the concentration of the mucin contained in the raw material solution may be, for example, 100.000 w / v% or less, 50.000 w / v% or less, 20.000 w / v% or less, or 10.000 w / v% or less.

[0035] In the present production method, the concentration of boric acid contained in the raw material solution is not particularly limited as long as it satisfies the relationship of the above formula (1) (Ln is the natural logarithm with e as the base).

[0036] The concentration of the boric acid contained in the raw material solution is preferably 1.000 mM or more, may be 10.000 mM or more, 50.000 mM or more, 100.000 mM or more, 150.000 mM or more, or 300.000 mM or more. The upper limit of the concentration of the boric acid contained in the raw material solution may be, for example, 1000.000 mM or less, 500.000 mM or less, or 100.000 mM or less.

[0037] In the above formula (1), LnB>-0.875A+8.306. In the formula (1), "8.306" may be changed. The "8.306" may be, for example, "8.310", "8.320", "8.330", "8.350", "8.400", "8.500", "8.600", or "9.000". With this configuration, the mucin gel (for example, a mucin gel in which mucins are gelled without chemically crosslinking them with a crosslinking agent, a mucin gel that can be sterilized by UV irradiation) can be produced.

[0038] The raw material solution may further contain an aqueous solvent. The aqueous solvent may be water alone or may be a mixed solvent of water and a hydrophilic organic solvent compatible with water. In the mixed solvent, the concentration of the hydrophilic organic solvent is not particularly limited.

[0039] The hydrophilic organic solvent is not particularly limited, but examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, pentanol, hexanol, and heptanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; nitriles such as acetonitrile and propionitrile; amides such as dimethylformamide and acetamide; polyols such as glycerin, ethylene glycol, and propylene glycol; dimethyl sulfoxide, pyridine, piperidine, etc. Among them, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, acetonitrile, propionitrile, glycerin, ethylene glycol, and propylene glycol are preferred because they are easy to remove. Moreover, methanol, ethanol, 1-propanol, 2-propanol, butanol, acetone, glycerin, ethylene glycol, propylene glycol, etc. are more preferable because they are easily available. Furthermore, methanol, ethanol, acetone, glycerin, ethylene glycol, and propylene glycol are particularly preferable.

[0040] The water content in the entire aqueous solvent that can constitute the raw material solution is not limited and may be, for example, 5 to 100% by weight, 10 to 100% by weight, 30 to 100% by weight, 50 to 100% by weight, 70 to 100% by weight, 90 to 100% by weight, or 95 to 100% by weight.

[0041] From the viewpoint of improving the properties of the resulting mucin gel, the raw material solution may contain substances other than mucin, boric acid, and the aqueous solvent (other substances), such as antioxidants, chelating agents, buffers, preservatives, surfactants, inorganic salts, polyphenols, metal ions, acids other than boric acid, bases, amino acids, peptides, proteins, sugars, nucleic acids, lipids, cells, bacteria, viruses, etc.

[0042] [1-4] Mucin gel In this specification, "mucin gel" refers to a gel containing mucin. In this specification, "gel" refers to a colloidal solution (sol) in which the dispersed matter forms an intermolecular network structure through intermolecular interactions. Details of mucin gel will be explained in <2. Mucin Gel> below.

[0043] [1-5] pH adjustment process This production method includes a pH adjustment step of adjusting the pH of a raw material solution containing mucin and boric acid to 7.5 or higher.

[0044] Since the present production method includes a pH adjustment step, the raw material solution containing mucin and boric acid can be gelled.

[0045] In this production method, the pH of the raw material solution is adjusted to 7.5 or more, may be adjusted to 8.0 or more, may be adjusted to 9.0 or more, may be adjusted to 10.0 or more, or may be adjusted to 11.0 or more. In this production method, the upper limit of the pH of the raw material solution is not particularly limited, and may be adjusted to, for example, 12.0 or less.

[0046] In this manufacturing method, the temperature of the raw material solution is not particularly limited, and may be, for example, from room temperature (1°C or higher and 40°C or lower) to 100°C. In addition, steam of an aqueous solvent may be used as an optional aqueous solvent that may be contained in the raw material solution. When an aqueous solvent or steam of an aqueous solvent at a high temperature of 60°C or higher is used, a sterilization effect can also be expected.

[0047] (Preparation of raw material solution) The present production method may include a step of preparing a raw material solution to be used in the pH adjustment step, prior to the pH adjustment step. The raw material solution preparation step is not particularly limited, and examples thereof include a step of mixing an aqueous solvent in which mucin is dispersed with an aqueous solvent in which boric acid is dispersed, a step of adding powders of mucin and boric acid to an aqueous solvent and stirring the mixture, a step of adding mucin to an aqueous solvent in which boric acid is dispersed and stirring the mixture, and a step of adding boric acid to an aqueous solvent in which mucin is dispersed and stirring the mixture.

[0048] The viscosity, elasticity, and surface tension of the raw material solution are not limited, and can be appropriately set according to a known method.

[0049] (UV irradiation process) The present production method may include a UV irradiation step of irradiating the mucin gel obtained by the pH adjustment step with UV light after the pH adjustment step. This configuration makes it possible to suitably produce a sterilized / sterilized mucin gel. The UV irradiation step that the present production method may include can also be said to be a step of killing bacteria and the like in the mucin gel by UV irradiation. Specific examples of methods for UV irradiation of mucin gel include, but are not limited to, a method of irradiating the mucin gel with ultraviolet light from a light source (e.g., a mercury lamp).

[0050] In the present production method, the intensity of the light source when irradiating the mucin gel with ultraviolet light is not particularly limited, but is, for example, 5 mW / cm 2 or more, 15 mW / cm 2 or more, 30 mW / cm 2 The upper limit of the light source intensity is not limited, but may be, for example, 100 mW / cm 2 Less than or equal to 50mW / cm 2 It may be the following.

[0051] In the present production method, the irradiation time when irradiating the mucin gel with ultraviolet light is not particularly limited, but may be, for example, 30 seconds or more, 60 seconds or more, or 120 seconds or more. The upper limit of the irradiation time is not limited, but may be, for example, 300 seconds or less, or 200 seconds or less.

[0052] In the present production method, the total irradiation amount when irradiating the mucin gel with ultraviolet light is not particularly limited as long as it is a total irradiation amount that can sterilize the mucin gel. For example, 2 or more, 450 mW sec / cm 2 or more, 600 mW sec / cm 2 or more, 750 mW sec / cm 2 or more, 900 mW sec / cm 2 The upper limit of the total irradiation amount is not limited, but may be, for example, 3000 mW sec / cm 2 Less than or equal to 1000mW·sec / cm 2 It may be the following.

[0053] <2. Mucin gel> The mucin gel contains mucin and boric acid and has a pH of 7.5 or higher. When the concentration of the mucin contained in the mucin gel is A [w / v%] and the concentration of the boric acid contained in the mucin gel is B [mM], the mucin gel satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base): LnB>-0.875A+8.306···(1).

[0054] The present mucin gel has the above-mentioned composition, and thus has the advantage that it can be gelled without chemically cross-linking mucin molecules using a cross-linking agent, and can be sterilized by UV irradiation.

[0055] The pH of the mucin gel is 7.5 or more, and may be 8.0 or more, 9.0 or more, 10.0 or more, or 11.0 or more. If the pH of the mucin gel is 7.5 or more, the mucin gel can be produced. The upper limit of the pH of the mucin gel is not limited, and may be, for example, 12.0 or less.

[0056] In the present production method, the concentration of mucin contained in the mucin gel is not particularly limited as long as it satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), where A is the concentration of mucin contained in the mucin gel [w / v %] and B is the concentration of boric acid contained in the mucin gel [mM]: LnB>-0.875A+8.306···(1).

[0057] The concentration of the mucin contained in the mucin gel is preferably 3.000 w / v% or more, may be 6.000 w / v% or more, 7.000 w / v% or more, 8.000 w / v% or more, or may be 10.000 w / v% or more. The upper limit of the concentration of the mucin contained in the raw material solution may be, for example, 100.000 w / v% or less, 50.000 w / v% or less, 20.000 w / v% or less, or 10.000 w / v% or less.

[0058] In the present production method, the concentration of boric acid contained in the raw material solution is not particularly limited as long as it satisfies the relationship of the above formula (1) (Ln is the natural logarithm with e as the base).

[0059] The concentration of the boric acid contained in the mucin gel is preferably 1.000 mM or more, may be 10.000 mM or more, 50.000 mM or more, 100.000 mM or more, 150.000 mM or more, or 300.000 mM or more. The upper limit of the concentration of the boric acid contained in the mucin gel may be, for example, 1000.000 mM or less, 500.000 mM or less, or 100.000 mM or less.

[0060] In the above formula (1), LnB>-0.875A+8.306. In the formula (1), "8.306" may be changed. The "8.306" may be, for example, "8.310", "8.320", "8.330", "8.350", "8.400", "8.500", "8.600", or "9.000". With this configuration, the mucin gel (for example, a mucin gel in which mucins are gelled without chemically crosslinking them with a crosslinking agent, a mucin gel that can be sterilized by UV irradiation) can be produced.

[0061] In this specification, the loss tangent (tan δ) value of the mucin gel is the value at an angular frequency of 10 rad / s when viscoelasticity measurement (strain: 10%) is carried out.

[0062] The loss tangent (tan δ) of the mucin gel is not particularly limited as long as it is 1.000 or less, but may be 0.500 or less, 0.300 or less, or 0.100 or less. If the loss tangent (tan δ) is 1.000 or less, it can be determined that the mucin gel is in a gel state, i.e., a mucin gel.

[0063] The complex elastic modulus of the mucin gel before and after UV treatment is 90.0% or more, and preferably 95.0% or more. However, the total UV irradiation dose for the mucin gel during the UV treatment is 900mW sec / cm 2 If the residual rate of the complex elastic modulus of the mucin gel is 90.0% or more, the viscoelasticity of the mucin gel does not change before and after UV irradiation, that is, the mucin gel is not altered by UV irradiation, which is preferable.

[0064] In one embodiment of the present invention, the mucin gel is produced by the present method.

[0065] Furthermore, the mucin gel may contain various components that are generated or not removed during the production process, so long as the effects of the present invention are achieved.

[0066] <3. Goods> An article comprising the mucin gel of the present invention is also one embodiment of the present invention. In this specification, "an article comprising the mucin gel of one embodiment of the present invention" may be referred to as "the article".

[0067] The present article has the advantage that it can be sterilized by UV irradiation, since it contains the above-mentioned mucin.

[0068] This product can be used for a variety of purposes, such as an in vitro evaluation device, a medicine, a quasi-drug, a cosmetic, a substrate, a collection material, a drug DDS device, a cryopreservation device, an adhesive, an artificial joint, an eye patch, a bandage, or a napkin. EXAMPLES

[0069] The present invention will be described in more detail with reference to the following examples and comparative examples. However, the present invention is not limited to these examples. Examples obtained by appropriately combining the technical means disclosed in each example are also included in the scope of the present invention.

[0070] [A. Viscoelasticity evaluation depending on mucin concentration and boric acid concentration] 1. Preparation of Test Solutions 1-1. Preparation of mucin solution Mucin (derived from porcine stomach) powder (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to purified water and stirred and dissolved at room temperature (1° C. or higher and 40° C. or lower) to obtain a mucin solution.

[0071] 1-2. Preparation of boric acid solution Boric acid (manufactured by Kosakai Pharmaceutical Co., Ltd.) was added to purified water and stirred and dissolved at room temperature to obtain a boric acid solution.

[0072] 1-3. Preparation of raw material solution containing mucin and boric acid The mucin solution obtained in "1-1. Preparation of mucin solution" above and the boric acid solution obtained in "1-2. Preparation of boric acid solution" above were mixed in appropriate amounts to obtain a raw material solution containing mucin and boric acid.

[0073] 1-4. Preparation of the composition (pH adjustment process) The raw solution obtained in the above "1-3. Preparation of raw solution containing mucin and boric acid" was added with 1 mol / L hydrochloric acid solution and 1 mol / L sodium hydroxide aqueous solution to adjust the pH, and an appropriate amount of purified water was added to obtain a composition.

[0074] 2. Viscoelasticity evaluation according to the influence of mucin concentration and boric acid concentration For 1 mL of the composition obtained in "1-4. Preparation of composition" above, dynamic viscoelasticity measurement was carried out using a viscoelasticity measuring device (MCR302, manufactured by Anton Paar Inc.) The measurement conditions were as follows. Measurement mode: Frequency dependent measurement Distortion: 10% Angular frequency: 0.1 to 10 rad / s (of which, the results for 10 rad / s were extracted and evaluated.) Fixture: Corn plate Jig diameter and angle: 25mm (angle: 2°) or 50mm (angle: 1°) Temperature: Room temperature (25±5℃) (Lower plate was set at 21℃).

[0075] 3.Results The composition, pH, and loss tangent (tan δ) at an angular frequency of 10 rad / s of the composition are shown in Table 1. A composition with a loss tangent (tan δ) of less than 1.000 was considered to be in a gel state, i.e., a mucin gel, and a composition with a loss tangent (tan δ) of 1.000 or more was considered to be in a liquid state. An image of the composition of Example 2 when added to a glass petri dish (left image) and an image of the composition when picked up with tweezers (right image) are shown in Figure 1.

[0076] [Table 1]

[0077] From Table 1, in Examples 1 and 2, which satisfied the above formula (1), the loss tangent (tan δ) was less than 1.000, and the composition was in a gel state. On the other hand, in Comparative Examples 1 and 2, which did not satisfy the above formula (1), the loss tangent (tan δ) was 1.000 or more, and the composition was in a liquid state.

[0078] [B. Evaluation of viscoelasticity as a function of pH] 4. Preparation of Test Solutions 4-1. Preparation of mucin solution A mucin solution was obtained by carrying out the same procedure as in "1-1. Preparation of mucin solution" above.

[0079] 4-2. Preparation of boric acid solution A boric acid solution was obtained by carrying out the same procedure as in "1-2. Preparation of boric acid solution" above.

[0080] 4-3. Preparation of raw material solution containing mucin and boric acid The same procedure as in "1-3. Preparation of a raw material solution containing mucin and boric acid" was carried out to obtain a raw material solution containing mucin and boric acid.

[0081] 4-4. Preparation of the composition The same procedure as in "1-4. Preparation of composition" above was carried out to obtain a composition.

[0082] 5. Evaluation of viscoelasticity as a function of pH The viscoelasticity of the composition obtained in "4-4. Preparation of composition" above was evaluated using the same procedures and conditions as in "2. Evaluation of viscoelasticity due to the influence of mucin concentration and boric acid concentration" above.

[0083] 6.Results Table 2 shows the composition, pH and loss tangent (tan δ) at an angular frequency of 10 rad / s.

[0084] [Table 2]

[0085] As seen from Table 2, in Examples 3 to 5 in which the pH was 7.5 or more, the loss tangent (tan δ) was less than 1.000, and the composition was in a gel state. In Comparative Examples 3 and 4 in which the pH was less than 7.5, the loss tangent (tan δ) was 1.000 or more, and the composition was in a liquid state.

[0086] C. Ultraviolet (UV) treatment of mucin gel and evaluation of viscoelasticity 7. Preparation of Test Solutions 7-1. Preparation of mucin solution A mucin solution was obtained by carrying out the same procedure as in "1-1. Preparation of mucin solution" above.

[0087] 7-2. Preparation of boric acid solution A boric acid solution was obtained by carrying out the same procedure as in "1-2. Preparation of boric acid solution" above.

[0088] 7-3. Preparation of raw material solution containing mucin and boric acid The same procedure as in "1-3. Preparation of a raw material solution containing mucin and boric acid" was carried out to obtain a raw material solution containing mucin and boric acid.

[0089] 7-4. Preparation of mucin gel A composition that would give a mucin gel was selected based on the results of [A. Viscoelasticity evaluation based on the influence of mucin concentration and boric acid concentration] and [B. Viscoelasticity evaluation based on the influence of pH]. A mucin gel was obtained by carrying out the same procedure as in "1-4. Preparation of composition" above.

[0090] 7-5. UV treatment of mucin gel 1 mL of the mucin gel prepared in "7-4. Preparation of mucin gel" above was added to a colorless transparent plastic bag (Unipack C-4, manufactured by Nippon Seisakusho Co., Ltd.) and sealed. The mucin gel was irradiated with UV light using a light source device (SX-UI500H, manufactured by Ushio Inc., lamp: ultra-high pressure mercury lamp). The UV irradiation conditions were as follows: ·Light source intensity: 15mW / cm 2 ·Irradiation time: 60sec Total irradiation dose: 900mW·sec / cm 2 The UV irradiation dose required to kill bacteria and yeast is approximately 300 mW / cm 2 (See IES LIGHTING HANDBOOK -The Standard Lighting Guide- First Edition, Illuminating Engineering Society, 1947.) The total UV irradiation amount in "7-5. Ultraviolet treatment of mucin gel" is approximately three times the amount of UV irradiation required for sterilization mentioned above.

[0091] 8.Results The composition of the mucin gel, pH, and the residual rate (%) of the complex elastic modulus of the mucin gel after UV treatment are shown in Table 3. When the residual rate (%) of the complex elastic modulus of the mucin gel after UV treatment is 90.0% or more, it was determined that the gel strength of the mucin gel does not change due to UV treatment.

[0092] [Table 3]

[0093] From Table 3, it was found that in all of the mucin gels of Examples 6 to 9, the residual complex modulus (%) after UV treatment was 90.0% or more, and the gel strength did not change even after UV treatment.

[0094] [D. Relationship between mucin concentration and boric acid concentration in the raw solution] 9. Preparation of Test Solutions 9-1. Preparation of mucin solution A mucin solution was obtained by carrying out the same procedure as in "1-1. Preparation of mucin solution" above.

[0095] 9-2. Preparation of boric acid solution A boric acid solution was obtained by carrying out the same procedure as in "1-2. Preparation of boric acid solution" above.

[0096] 9-3. Preparation of raw material solution containing mucin and boric acid The same procedure as in "1-3. Preparation of a raw material solution containing mucin and boric acid" was carried out to obtain a raw material solution containing mucin and boric acid.

[0097] 9-4. Preparation of the composition A 1 mol / L aqueous solution of sodium hydroxide was added to the raw solution obtained in the above "9-3. Preparation of raw solution containing mucin and boric acid" to adjust the pH to 7.5 or higher, thereby obtaining a composition.

[0098] 10. Evaluation of Gelation The compositions obtained in "9-4. Preparation of Composition" above were visually evaluated for gelation. Compositions in which gelation was observed were marked with an ◯, and compositions in which gelation was not observed were marked with an ×. The results are shown in Table 4.

[0099] [Table 4]

[0100] 11. Calculation of the gelation boundary line, equation (1) Based on Table 4, Examples 10 to 19 and Comparative Examples 5 to 8 were plotted with A: mucin concentration (w / v%) on the horizontal axis and B: boric acid concentration (mM) on the vertical axis. Next, the vertical axis was re-plotted with LnB (Ln is the natural logarithm with e as the base). Thereafter, the gelation boundary line was set with reference to an approximation curve obtained by approximating Comparative Examples 5 to 8 using the least squares method. The equation for the set boundary line was LnB=-0.875A+8.306. The results are shown in FIG. 2. [Industrial Applicability]

[0101] According to one embodiment of the present invention, a mucin gel can be produced that is gelled without chemically crosslinking mucins with a crosslinking agent and that can be sterilized by UV irradiation. Therefore, one embodiment of the present invention can be suitably used for in vitro evaluation devices, medicines, quasi-drugs, cosmetics, substrates, collection materials, pharmaceutical DDS devices, cryopreservation devices, adhesives, artificial joints, eye patches, bandages, napkins, etc.

Claims

1. The method includes a pH adjustment step of adjusting the pH of a raw material solution containing mucin and boric acid to 7.5 or more, A method for producing a mucin gel, which satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), when the concentration of the mucin contained in the raw material solution is A [w / v %] and the concentration of the boric acid contained in the raw material solution is B [mM]: LnB>-0.875A+8.306...(1).

2. The method for producing a mucin gel according to claim 1, wherein the value of A is 3.000 w / v % or more.

3. The method for producing a mucin gel according to claim 1, wherein the value of B is 1.000 mM or more.

4. A mucin gel containing mucin and boric acid and having a pH of 7.5 or more, A mucin gel that satisfies the relationship of formula (1) (Ln is the natural logarithm with e as the base), where A [w / v %] is the concentration of the mucin contained in the mucin gel, and B [mM] is the concentration of the boric acid contained in the mucin gel: LnB>-0.875A+8.306...(1).

5. The mucin gel according to claim 4, wherein the value of A is 3.000 w / v% or more.

6. The mucin gel according to claim 4, wherein the value of B is 1.000 mM or more.

7. The mucin gel according to claim 4, wherein the loss tangent (tan δ) value of the mucin gel is 1.000 or less. (The loss tangent (tan δ) value is the value at an angular frequency of 10 rad / s when viscoelasticity measurement (strain: 10%) was performed.)

8. The mucin gel according to claim 4, wherein the complex elastic modulus of the mucin gel remains at 90.0% or more before and after the mucin gel is subjected to UV treatment. (The total UV irradiation dose for the mucin gel in the UV treatment was 900 mW·sec / cm ２ (It is.)

9. An article comprising the mucin gel of claim 4.

10. The article according to claim 9 , wherein the article is an in vitro evaluation device, a medicine, a quasi-drug, a cosmetic, a substrate, a collection material, a pharmaceutical DDS device, a cryopreservation device, an adhesive, an artificial joint, an eye patch, a bandage, or a napkin.

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