Artificial blood

Abstract

The objective of the present invention is to provide an inexpensive artificial blood that has high viscosity and properties similar to actual menstrual blood in terms of color and stain removal behavior. [Solution] The artificial blood according to the present invention is an artificial blood comprising a thickening agent and hemoglobin, characterized in that the content of the thickening agent is 0.30% by mass or more of 100% by mass of the artificial blood.

Description

Technical Field

[0005]

[0001] The present invention relates to artificial blood, and particularly to artificial blood that simulates highly viscous menstrual blood.

Background Art

[0002] In recent years, there has been a global Femtech boom. Femtech is a coined term combining Female and Technology, referring to services and products that solve women's health problems through technology. Application fields of Femtech include the menstrual field, pregnancy / infertility field, menopause field, etc. In the menstrual field, product development such as menstrual absorbent underwear, menstrual cups, and menstrual cycle apps is underway.

[0003] Performance requirements for menstrual products include the ability to absorb menstrual blood without leakage, and the ability for dirt to be easily removed by washing even if menstrual blood adheres. Therefore, in the performance evaluation of products, bovine blood etc. has been adopted as artificial blood to date. Also, as artificial blood, for example, artificial blood described in Non-Patent Document 1 is also known.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Menstrual blood has a higher viscosity than normal blood flowing through the body. Furthermore, the viscosity of menstrual blood varies depending on individual differences and the menstrual cycle (early, middle, and late stages of menstruation). Conventional bovine blood and artificial blood described in Non-Patent Literature 1 have low viscosity, making it difficult to evaluate them for practical use. The difficulty in evaluation is due to the water absorption process caused by the difference in viscosity. When a highly viscous liquid such as menstrual blood is absorbed by an absorbent material with high water absorption, the liquid first spreads on the surface of the absorbent material before being absorbed by the absorbent material. In contrast, when a liquid with low viscosity is absorbed by an absorbent material with high water absorption, the liquid does not spread on the surface of the absorbent material before being absorbed by the absorbent material.

[0006] Unlike disposable sanitary napkins, absorbent underwear is intended for repeated use. Generally, the suitability of fabrics for products intended for repeated use, such as absorbent underwear, is determined through various evaluation tests. These evaluation tests require artificial blood that closely resembles actual menstrual blood in terms of color, stain removal behavior, and other characteristics. However, while bovine blood, which has been used conventionally, offers excellent blood reproducibility, it is expensive and unsuitable for testing. Furthermore, the artificial blood described in Non-Patent Document 1 is inexpensive, but uses dyes as coloring components, resulting in poor reproducibility in terms of color and stain removal.

[0007] This invention was made against the backdrop of the aforementioned prior art problems. In other words, the objective of this invention is to provide an inexpensive artificial blood that has high viscosity and properties similar to actual menstrual blood in terms of color and stain removal behavior. [Means for solving the problem]

[0008] As a result of diligent research, the inventors of the present invention have found that the above-mentioned problems can be solved by the means described below, and have arrived at the present invention. That is, the present invention consists of the following configuration.

[0009] [1] Artificial blood containing a thickener and hemoglobin, Artificial blood characterized in that the amount of the thickening agent is 0.30% by mass or more of 100% by mass of the artificial blood. [2] The artificial blood according to [1], wherein the amount of the thickening agent is 3.00% by mass or less in 100% by mass of the artificial blood. [3] The artificial blood according to [1] or [2], wherein the amaranth pigment content is 0.08% by mass or less per 100% by mass of the artificial blood. [4] The artificial blood according to any one of [1] to [3], wherein the ratio of the thickening agent to the hemoglobin (hemoglobin / thickening agent) is 0.2 to 10.0 by mass. [5] Artificial blood as described in any one of [1] to [4], wherein the thickener is carboxymethylcellulose. [6] Artificial blood as described in any one of [1] to [5], wherein the viscosity at 20°C is 140 to 200 mPa·s. [7] An evaluation method comprising the step of applying artificial blood described in any one of [1] to [6] to a test subject. [8] Artificial blood obtained by mixing solution A and solution B, The aforementioned liquid A contains a thickening agent, The aforementioned solution B contains hemoglobin, Artificial blood characterized by containing a thickening agent at a concentration of 0.30% by mass or more per 100% by mass of artificial blood. [Effects of the Invention]

[0010] According to the present invention, an inexpensive artificial blood is provided that has high viscosity and properties similar to actual menstrual blood in terms of color and stain removal behavior. Furthermore, the artificial blood of the present invention makes it possible to evaluate its performance against viscous, thick blood. [Modes for carrying out the invention]

[0011] 1)Artificial blood The artificial blood of the present invention is an artificial blood comprising a thickening agent and hemoglobin, characterized in that the content of the thickening agent is 0.30% by mass or more of 100% by mass of the artificial blood. The artificial blood having the above characteristics has high viscosity and characteristics similar to actual menstrual blood in terms of color and stain removal behavior.

[0012] The artificial blood of the present invention contains a thickening agent. The content of the thickening agent is 0.30% by mass or more, preferably 0.50 to 3.00% by mass, more preferably 0.80 to 2.00% by mass, and even more preferably 1.00 to 1.80% by mass, based on 100% by mass of the artificial blood. By containing a predetermined amount or more of the thickening agent, the artificial blood of the present invention can reproduce blood with high viscosity, such as menstrual blood. On the other hand, if the content of the thickening agent is too high, the viscosity of the artificial blood will increase too much, and the artificial blood may not penetrate the sample sufficiently during evaluation tests, which may prevent the evaluation tests from being performed properly. Therefore, it is preferable that the content of the thickening agent be below the upper limit. It is also known that the viscosity of menstrual blood changes according to the menstrual cycle. Since the content of the thickening agent is adjustable, the viscosity of the artificial blood can be freely adjusted in accordance with these changes in the viscosity of menstrual blood associated with the menstrual cycle.

[0013] In this disclosure, a thickening agent specifically refers to a component that, when added to artificial blood, can improve the viscosity of the artificial blood compared to before the thickening agent was added. Examples of thickening agents include carboxymethylcellulose, polyvinyl alcohol, ethylene glycol, gelatin, and various sugars, with carboxymethylcellulose being preferred. Carboxymethylcellulose is an anionic water-soluble polymer obtained from cellulose as a raw material, and has excellent thickening, water absorption, and water retention properties.

[0014] The artificial blood of the present invention further contains hemoglobin. Non-patent document 1 uses amaranth dye (also known as acid red 27, CAS number: 915-67-3) as a component corresponding to blood components, but the present invention uses hemoglobin as a component corresponding to blood components. Hemoglobin is a red-colored protein present in red blood cells, and by incorporating hemoglobin into artificial blood, the reproducibility of the color of menstrual blood and its behavior such as stain removal is improved. Furthermore, by incorporating hemoglobin into artificial blood, it becomes possible to subject samples to the luminol test with the artificial blood of the present invention dropped onto them. Dark-colored fabrics such as black or navy blue are often used in the crotch area of ​​absorbent shorts to make stains less noticeable. Stain removal is generally evaluated by visually determining the degree of staining (for example, by using a gray scale for staining in accordance with JIS L 0805:2005), but with dark-colored fabrics, the stain and the color of the fabric overlap, making visual judgment difficult. In evaluating stain removal on dark-colored fabrics, a test utilizing the luminol reaction allows for easy visual determination of the degree of staining, as the presence of blood is visualized by the luminol reaction, which causes a purple-blue emission. The hemoglobin content in the artificial blood of the present invention is preferably 1 to 10% by mass, more preferably 2 to 9% by mass, and even more preferably 3 to 8% by mass, based on the amount of hemoglobin contained in the blood of an adult woman.

[0015] Since the artificial blood of the present invention contains hemoglobin, the amount of amaranth dye used in Non-Patent Document 1 can be reduced. Specifically, the amount of amaranth dye is preferably 0.08% by mass or less, more preferably 0.05% by mass or less, even more preferably 0.03% by mass or less, and particularly preferably 0.00% by mass, per 100% by mass of the artificial blood.

[0016] In the artificial blood of the present invention, the content ratio of the thickener and the hemoglobin is preferably (hemoglobin / thickener), based on mass, 0.2 to 10.0, more preferably 1.0 to 9.0, still more preferably 2.0 to 8.0, and even more preferably 3.0 to 7.0. Within the above range, it becomes an artificial blood that has a high viscosity like menstrual blood but is excellent in the reproducibility of color, taste, and the behavior of stain removal.

[0017] The artificial blood of the present invention may contain other components in addition to the above-described thickener and hemoglobin. Examples of other components include stabilizers such as polyethylene glycol sorbitan monolaurate; pseudo-body fluid components such as sodium chloride, potassium dihydrogen phosphate, disodium hydrogen phosphate, and purified water.

[0018] The artificial blood of the present invention may contain an odor component as needed. Examples of the odor component include ketones such as 1-octen-3-one; amines such as ammonia and trimethylamine; sulfur compounds such as methyl mercaptan; and the like.

[0019] The viscosity of the artificial blood of the present invention at 20°C is preferably 140 to 200 mPa·s, more preferably 150 to 180 mPa·s. Also, the viscosity of the artificial blood of the present invention at 4°C is preferably 140 to 200 mPa·s, more preferably 150 to 180 mPa·s. Within the above range, it is possible to provide an artificial blood having characteristics close to those of actual menstrual blood. The viscosity may be appropriately measured with a B-type viscometer or the like.

[0020] 2) Method for producing artificial blood The artificial blood can be produced by a method including a step of mixing a thickener, hemoglobin, and other components used as needed.

[0021] 3) Method for storing artificial blood The artificial blood of the present invention is preferably stored at 0°C or higher, more preferably 5°C or higher, still more preferably 10°C or higher, preferably 40°C or lower, more preferably 35°C or lower, and still more preferably 30°C or lower. The artificial blood of the present invention can suppress the decrease in viscosity as the storage temperature decreases. Therefore, when stored under normal temperature conditions (15 to 25°C), it is preferably used within 48 hours, and when stored under refrigeration conditions (0 to 10°C), it is preferably used within 96 hours.

[0022] As described above, the artificial blood of the present invention tends to have a decrease in viscosity under normal temperature storage compared to storage under refrigeration conditions. Therefore, it is also possible to separate the components of the artificial blood and mix them immediately before use. That is, the present disclosure also includes an artificial blood obtained by mixing a liquid A and a liquid B, wherein the liquid A contains a thickening agent, the liquid B contains hemoglobin, and the content of the thickening agent is 0.30% by mass or more in 100% by mass of the artificial blood. Other components other than the thickening agent and hemoglobin contained in the artificial blood may be contained in either the liquid A or the liquid B. For details of the artificial blood obtained by mixing the liquid A and the liquid B, the description of the artificial blood described above may be appropriately referred to except for separating the components of the artificial blood.

[0023] 4) Evaluation method using artificial blood The artificial blood of the present invention is used as simulated blood to simulate menstrual blood. The evaluation method using the artificial blood of the present invention includes the step of applying the artificial blood of the present invention to a test subject, thereby allowing evaluation of the behavior of the artificial blood on the test subject. Examples of test subjects include sanitary products such as absorbent shorts; toilet products such as toilets, toilet seats, and shower-type washing devices represented by Washlet® and Shower Toilet®; and human body parts such as the buttocks and genitals. Examples of evaluation methods for sanitary products include evaluation of water absorption capacity to assess how much menstrual blood the sample fabric can absorb; evaluation of wetting return to the fabric surface to assess how much menstrual blood absorbed by the sample fabric returns to the fabric surface under pressure; and evaluation of stain resistance to assess how easily menstrual blood adheres to the sample fabric or how easily it washes off. Examples of evaluation methods for toilet products include evaluation of stain resistance to assess how easily menstrual blood adheres to the test subject or how easily it washes off. Other methods for evaluating the human body include evaluating how easily menstrual blood adheres to the skin, or how easily dirt attached to the skin can be removed by the aforementioned shower-type washing device, and evaluating skin dirt.

[0024] 4-1) Evaluation of water absorption The following details various evaluation methods suitable for evaluating sanitary products. First, in evaluating water absorption, artificial blood is dropped onto the sample fabric, and after a certain period of time, the degree of leakage of the artificial blood from the sample fabric is evaluated. It is also possible to place a weight on the dropper to promote absorption.

[0025] 4-2) Evaluation of re-wetting For evaluating re-wetting, artificial blood is dropped onto the sample fabric, and after a certain period of time, filter paper is placed over the dropper to absorb the artificial blood. The amount of artificial blood absorbed by the filter paper is used for evaluation. When placing the filter paper over the dropper to absorb the artificial blood, it is also possible to place a weight on the filter paper to promote absorption. Re-wetting evaluates how much of the menstrual blood absorbed by the sample fabric returns to the fabric surface under pressure. Re-wetting is related to the feeling of stickiness when worn and to cleanliness and hygiene, making it an important indicator for consumers.

[0026] 4-3) Evaluation of stain resistance For evaluating stain resistance, artificial blood is dropped onto a sample fabric, and after a certain period of time, the sample fabric that has absorbed the artificial blood is washed. The degree to which the artificial blood was removed by washing is evaluated by determining the color difference before and after washing using a stain grayscale or the like in accordance with JIS L 0805:2005.

[0027] 4-4) Sample The artificial blood of the present invention can be evaluated in various ways by dropping it onto the product itself, such as absorbent shorts, or onto the fabric used in such products. By using the product itself, evaluations close to actual usage can be obtained. On the other hand, by using the fabric, it becomes possible to evaluate various functions of the fabric itself, such as water absorption capacity, re-wetting, and stain resistance. In the case of fabric, it is preferable that the size be 3 to 14 cm x 3 to 14 cm, more preferably 5 to 10 cm x 5 to 10 cm. [Examples]

[0028] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass".

[0029] <Example 1: Preparation of artificial blood> Artificial blood was prepared by mixing the following components. Carboxymethylcellulose (CMC, manufactured by Sigma-Aldrich) 10 units Polyethylene glycol sorbitan monolaurate (Sigma-Aldrich "TWEEN® 20") 0.04 parts Sodium chloride (Sigma-Aldrich) 2.4 parts Monopotassium dihydrogen phosphate (KH2PO4, manufactured by Sigma-Aldrich) 1.2 parts Disodium hydrogen phosphate (Na2HPO4, manufactured by Sigma-Aldrich) 4.3 parts Purified water 1000 parts Hemoglobin (Sigma-Aldrich, derived from bovine blood) 55.0 parts The CMC concentration in the artificial blood prepared in Example 1 was 0.93% by mass.

[0030] <Example 2: Preparation of artificial blood> Artificial blood was prepared in the same manner as in Example 1, except that the amount of CMC was changed from 10 parts to 15 parts. The CMC concentration in the artificial blood prepared in Example 2 was 1.39% by mass.

[0031] <Example 3: Preparation of artificial blood> Artificial blood was prepared in the same manner as in Example 1, except that the amount of CMC was changed from 10 parts to 20 parts. The CMC concentration in the artificial blood prepared in Example 3 was 1.85% by mass.

[0032] [Evaluation of viscosity (reproducibility)] Forty-one female staff members from the Boken Quality Evaluation Institute were selected as Tester Group A, and fifteen test collaborators were selected as Tester Group B. A questionnaire was administered to them regarding the viscosity of the artificial blood obtained in Examples 1-3. They were asked to select the artificial blood that most closely matched the viscosity of actual menstrual blood from among the three. The results of the questionnaires from the testers were then compiled. As shown in Table 1, the artificial blood that best reproduced the viscosity of menstrual blood was the artificial blood from Example 2.

[0033] [Table 1]

[0034] [Evaluation of viscosity (storage temperature)] The viscosity change under storage conditions was investigated using the artificial blood obtained in Example 2. 200g of the artificial blood obtained in Example 2 was placed in a wide-mouthed PET bottle and stored for 12 days from July 26 to August 6 under room temperature storage conditions (temperature 20°C, humidity 65%) and refrigerated storage conditions (temperature 4°C, humidity 40%). Midway through the storage period, the artificial blood was removed from the wide-mouthed PET bottle and its viscosity was measured at the same temperature as the storage conditions using a B-type viscometer (TVB-25 viscometer manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 2. As shown in Table 2, the viscosity of the artificial blood decreased significantly early under room temperature storage conditions, but it was found that the change in viscosity over time could be suppressed under refrigerated storage conditions.

[0035] [Table 2]

[0036] [Evaluation of stain resistance] Using the artificial blood obtained in Examples 1-3, we investigated how stains were removed due to differences in viscosity. 0.2 g of artificial blood was dropped onto a sample fabric (cotton cloth, "Kanakin No. 3" manufactured by the Japanese Standards Association), left for 24 hours, and then washed according to the C4M method described in Annex E of JIS L 1930:2024. After that, the color difference before and after washing was determined using a stain grayscale according to JIS L 0805:2005. The results are as follows. When using artificial blood from Example 1 (CMC: 10 parts): Grade 3-4 When using artificial blood from Example 2 (CMC: 15 parts): Grade 3 When using artificial blood from Example 3 (CMC: 20 parts): Grade 4 As the color difference results show, Example 2 yielded the most severe results. Example 3 showed improved color difference compared to Example 2, but this is thought to be due to the artificial blood in Example 3 having too high a viscosity, resulting in insufficient penetration into the fabric and the artificial blood solidifying on the surface of the fabric. In other words, in terms of evaluating stain resistance, the artificial blood in Examples 1 and 2 is considered suitable as menstrual blood.

[0037] [Evaluation of the luminol reaction] The washed fabric samples prepared in the [Stain Resistance Evaluation] were subjected to a luminol test. The test was conducted in a darkroom by dropping luminol reagent onto the washed test fabric and visually determining whether or not luminescence was observed. Luminescence was observed in all cases using the artificial blood from Examples 1 to 3.

Claims

1. Artificial blood containing a thickening agent and hemoglobin, Artificial blood characterized in that the amount of the thickening agent is 0.30% by mass or more of 100% by mass of the artificial blood.

2. The artificial blood according to claim 1, wherein the content of the thickening agent is 3.00% by mass or less in 100% by mass of the artificial blood.

3. The artificial blood according to claim 1 or 2, wherein the amaranth pigment content is 0.08% by mass or less per 100% by mass of the artificial blood.

4. The artificial blood according to claim 1 or 2, wherein the content ratio of the thickening agent to the hemoglobin (hemoglobin / thickening agent) is 0.2 to 10.0 by mass.

5. The artificial blood according to claim 1 or 2, wherein the thickening agent is carboxymethylcellulose.

6. The artificial blood according to claim 1 or 2, wherein the viscosity at 20°C is 140 to 200 mPa·s.

7. An evaluation method comprising the step of applying the artificial blood described in claim 1 or 2 to a test subject.

8. Artificial blood obtained by mixing solution A and solution B, The aforementioned liquid A contains a thickening agent, The aforementioned solution B contains hemoglobin, Artificial blood characterized by containing a thickening agent of 0.30% by mass or more of 100% by mass of artificial blood.

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