Taste sensor probe

Abstract

To provide a probe for a taste sensor enabling measurement with a small amount of sample and having a small variation in measurement results.SOLUTION: A probe for a taste sensor comprises a sample holder and a chip. The sample holder comprises: a sample holding region having a first region and a second region; an injection port for injecting a sample into the first region; a wall defining the second region; at least one opening part provided in the wall; and at least one air vent port provided in the second region. The chip comprises a terminal part, a wiring part, and at least one electrode part. The sample enters the second region through the opening part. The first region and the second region are in fluid communication. The electrode part contacts the sample in the second region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a taste sensor probe, and more particularly to a taste sensor probe equipped with a sample holder. [Background technology]

[0002] Quantifying taste, one of the five human senses, can provide objective indicators for considering adding high added value to food products and for controlling the quality of food production, so there is a strong need for it and it is attracting a great deal of interest in the food industry. In addition, in the field of drug discovery, taste sensors are often used in the development of masking technologies to suppress bitterness.

[0003] However, conventional taste sensors are large and require a large amount of sample solution for measurement, making it difficult to measure samples that only a small amount can be secured. Furthermore, when measuring multiple samples at once, a great deal of effort is required to prepare the sample solution, which places a burden on the tester.

[0004] Therefore, small taste sensors that can measure even small amounts of sample have been developed (Patent Document 1 and Patent Document 2). In particular, Patent Document 1 discloses a small taste sensor that can measure taste by dropping a small amount of sample solution onto a sensor chip.

[0005] However, the method of dropping a small amount of sample onto the sensor chip has the problem of large variability in measurement results, especially for taste substances that interact with lipid membranes via hydrophobic interactions, such as tannic acid, quinine hydrochloride, and iso-α-acids, which tend to be more prone to variability when the sample volume is small. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-248669 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-57459 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a taste sensor probe that allows measurement with a small amount of sample and produces measurement results with little variability. [Means for solving the problem]

[0008] One embodiment of the present invention is a taste sensor probe comprising a sample holder and a chip, wherein the sample holder comprises a sample holding area having a first area and a second area, an injection port for injecting a sample into the first area, a wall defining the second area, at least one opening in the wall, and at least one air vent in the second area; the chip comprises a terminal portion, a wiring portion, and at least one electrode portion, wherein the sample enters the second area through the opening, the first area and the second area are fluidly connected, and the electrode portion contacts the sample in the second area. [Effects of the Invention]

[0009] As described above, the taste sensor probe of the present invention includes a sample holder, which makes it possible to easily measure taste even when the sample is small. Furthermore, the taste sensor probe of the present invention has the effect of reducing variability in measurement results by having the wall suppress the flow of the sample within the sample holder.

[0010] In addition, by using the taste sensor probe of the present invention, the potential stabilizes in a shorter time, thereby shortening the measurement time. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows a first embodiment of the sample holder of the present invention. [Figure 2] FIG. 2 shows a second embodiment of the sample holder of the present invention. [Figure 3] FIG. 3 shows a third embodiment of the sample holder of the present invention. [Figure 4] FIG. 4 shows a fourth embodiment of the sample holder of the present invention. [Figure 5] FIG. 5 shows one embodiment of the chip of the present invention. [Figure 6] FIG. 6 illustrates an embodiment of the taste sensor probe of the present invention when in use. [Figure 7] FIG. 7 illustrates a small-sized taste sensor system equipped with a taste sensor probe of the present invention. [Figure 8] FIG. 8 shows a comparison of the response voltages of the present invention and the comparative example when the injection direction is changed according to Example 1. [Figure 9] FIG. 9 shows a comparison of response voltages between the present invention and the comparative example when the injection rate of the sample solution is changed according to Example 2. [Figure 10] FIG. 10 shows the response voltage of each electrode when the height of the second region of the sample holder of the present invention is changed according to Example 3. [Figure 11] FIG. 11 shows the change over time in the response voltage variation in the first and fourth embodiments of the sample holder of the present invention according to Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In the drawings, the same reference numerals indicate the same components. Duplicate descriptions of the same components may be omitted.

[0013] (Taste sensor probe) A taste sensor probe 400 according to a first embodiment of the present invention includes a sample holder 100 and a chip 200. The first embodiment of the present invention will be described below, but taste sensor probes 400 according to other embodiments including sample holders 101 to 103 also provide similar functions when assigned the same reference numerals.

[0014] (sample holder) The sample holder 100 of the present invention comprises a sample holding area having a first area 15 and a second area 16, an inlet 13 for injecting a sample into the first area 15, a wall 11 defining the second area 16, at least one opening 12 provided in the wall 11, and at least one air vent 14 provided in the second area 16. In the sample holder 100 of the present invention, the sample injected into the first area 15 through the inlet 13 enters the second area 16, which is in fluid communication with the first area 15, through the opening 12. In the second area 16, the sample comes into contact with an electrode section 23 (described below).

[0015] As used herein, the first region 15 refers to a region that initially receives the sample injected through the injection port 13. The first region 15 may have a wall separate from the wall 11 that defines the second region, either inside the first region 15 or at least on a portion of its outer edge. When the first region 15 has a separate wall on its outer edge, the separate wall has at least one opening through which the sample flows out of the first region 15. In the sample holder 100 of the present invention, the sample that flows out of the first region 15 enters the second region 16 through the opening 12, thereby establishing fluid communication between the first region 15 and the second region 16. In the sample holder 100, any configuration may be used between the first region 15 and the second region 16 as long as they can be fluidically connected. For example, the first region 15 and the second region 16 may be adjacent to each other via the opening 12, and there may be another region between the first region 15 and the second region 16 that is different from the first region 15 and the second region 16.

[0016] Sample holding area In the taste sensor probe 400 of the present invention, the sample holder 100 has a first region 15 and a second region 16, and is provided with a sample holding area capable of holding a sample. The sample holding area can have any shape, but is preferably a shape with symmetry, such as line symmetry or point symmetry. Examples of symmetrical shapes include, but are not limited to, circles and polygons such as squares, hexagons, and octagons, with circles being more preferred.

[0017] The outer periphery of the sample holding area may be surrounded by a second wall 17. The second wall 17 may be a part of the sample holder, or may be provided by a member separate from the sample holder. Examples of such a member include, but are not limited to, a sealing member such as an O-ring.

[0018] The sample holding area can have any height as long as it can hold a sufficient amount of sample for measurement. The height of the sample holding area is not limited to these values, but can be, for example, 0.3 mm to 10.0 mm, preferably 0.5 mm to 5.0 mm, and more preferably 1.0 mm to 3.5 mm.

[0019] Inlet The sample holder 100 of the present invention includes an injection port 13 for injecting a sample into the first region 15. The injection port 13 may have any shape and size as long as it allows the sample to be injected. The injection port 13 may also include an injection guide 18. The injection guide 18 generally has the form of a wall provided around the injection port 13. When the injection port 13 includes the injection guide 18, the momentum of the injected sample is reduced by colliding with the injection guide 18, which helps to further reduce variability in measurement results.

[0020] wall In the taste sensor probe of the present invention, the sample holder 100 further includes a wall 11. The wall 11 is a wall that defines the second region 16, and has the function of holding the sample around the electrode section 23. Furthermore, when the wall 11 is present on a straight line connecting the injection port 13 and the electrode section 23, the wall 11 also functions as a barrier that reduces the momentum of the sample injected from the injection port 13 before it comes into contact with the electrode section 23.

[0021] The wall 11 may have any shape. In one embodiment, the wall 11 may be provided around the injection port 13 to define a first region 15 around the injection port 13 (see FIG. 1). In another embodiment, a plurality of walls 11 may be provided (see FIGS. 2 to 4). For example, in a second embodiment, a plurality of walls 11 may be arranged radially (see FIG. 2). In another embodiment, when the chip has a plurality of electrode portions 23, the wall 11 may define a plurality of second regions 16 for each electrode portion 23 (see FIGS. 3 and 4).

[0022] The wall 11 can be of any height, but in order to prevent the flow of the sample, it is preferable that the wall 11 be the same height as the sample holding area. The height of the wall 11 is not limited to these values, but can be, for example, 0.3 mm to 10.0 mm, preferably 0.5 mm to 5.0 mm, and more preferably 1.0 mm to 3.5 mm.

[0023] The surfaces of the first region 15 and the second region 16 are preferably liquid-repellent to the sample to be measured. The liquid-repellent properties may be provided from the beginning by forming the sample holder 100 itself from a liquid-repellent material, or the liquid-repellent properties may be imparted by forming the sample holder 100 from a non-liquid-repellent material and coating the surfaces of the first region 15 and the second region 16 with a liquid-repellent material.

[0024] opening The sample holder 100 of the present invention has at least one opening 12 formed in a wall 11. A sample injected into a first region 15 through an inlet 13 enters a second region 16 that is in fluid communication with the first region through the opening 12. The opening 12 can be of any shape and size.

[0025] Air vent The sample holder 100 of the present invention has at least one air vent 14 provided in the second region 16. In this specification, the air vent 14 refers to an opening through which air escapes from the sample holder 100 while the sample is being injected into the sample holder 100. Only one air vent 14 may be provided, or multiple air vent 14 may be provided. For example, in an embodiment in which multiple second regions 16 are provided, each of the multiple second regions 16 may be provided with an air vent 14. The air vent 14 may be provided anywhere within the second region 16, but is preferably provided at or near the end of the path through which the sample flows, in order to fill the second region 16 with the sample. The air vent 14 may have any shape and size.

[0026] (Another embodiment of the taste sensor probe) A second embodiment of the taste sensor probe 400 includes the sample holder 101 of the second embodiment shown in Fig. 2. The sample holder 101 includes radially arranged walls 11 that are integral with the second walls 17, an injection port 13 that has an injection guide 18, and six openings 12. In the sample holder 101, by increasing the volume of the walls 11, the volume of the second regions 16 can be reduced, and therefore the amount of sample required for measurement can be reduced. For the sample holder 101, the electrode portions 23 of the chip 200 are arranged in each of the six second regions 16.

[0027] In the first embodiment, the sample flowing out of the opening 12 flows along the second region 16 and sequentially contacts each electrode 23. In contrast, in this configuration, the path the injected sample takes until it contacts each electrode 23 is the same regardless of the position of the electrode 23, so the measurement results are not affected by the position of the electrode 23. In the sample holder 101, the injection guide 18 reduces the momentum of the sample injected through the injection port 13, thereby helping to reduce variability in measurement results resulting from the sample flow rate. Furthermore, the radially arranged walls 11 impede the flow of the sample around the electrode 23, further reducing variability and shortening the time it takes for the potential to stabilize, enabling measurements to be taken in a shorter time. Furthermore, when the lipid membrane 24 constituting the electrode portion 23 comes into contact with a sample, components of the lipid membrane 24 may dissolve into the sample. However, by configuring the electrode portion 23 so that a wall 11 is placed between each electrode portion 23, the lipid membrane components dissolved into the sample can be prevented from diffusing, thereby preventing the lipid membrane 24 from being contaminated by components of other lipid membranes 24.

[0028] A third embodiment of the taste sensor probe 400 includes the sample holder 102 of the third embodiment shown in Fig. 3. In the sample holder 102, a plurality of walls 11 are arranged, each defining a second region 16. An air vent 14 is provided in each of the plurality of second regions 16, thereby allowing each second region 16 to be filled with sample. In this embodiment, the second wall is provided by attaching a member (not shown) separate from the sample holder, such as an O-ring, to the outside of the sample holding region.

[0029] The sample holder 102 has a wall 11 on the line connecting the injection port 13 and the electrode section 23, which reduces the momentum of the injected sample before it comes into contact with the electrode section 23, thereby reducing measurement errors resulting from the injection speed. Furthermore, by providing a second region 16 for each electrode section 23, the flow of the sample around the electrode section 23 can be suppressed. This not only reduces the variation in measurement results, but also shortens the time it takes for the potential to stabilize, enabling measurements to be taken in a shorter time. In addition, since the movement of the sample between each second region 16 is restricted, contamination between each lipid membrane 24 can also be prevented.

[0030] A fourth embodiment of the taste sensor probe 400 of the present invention includes the sample holder 103 of the fourth embodiment, as shown in FIG. 4. The sample holder 103 is a modified example of the sample holder 102 of the third embodiment. The sample holder 103 has an opening 12 that is smaller than that of the sample holder 102 of the third embodiment. By making the opening 12 smaller, the sample holder 103 can further suppress the flow of the sample around the electrode section 23, thereby further reducing the variability in measurement results and further shortening the measurement time. In addition, since the movement of the sample between each second region 16 is restricted, contamination between each lipid membrane 24 can also be prevented.

[0031] (Manufacturing method of sample holder) The sample holder 100 may be made of any material that can hold a sample and does not interact with the sample. Examples of materials that can be used to make the sample holder 100 include, but are not limited to, glass, synthetic resin, synthetic rubber, ceramics, water-resistant paper, and wood, with synthetic resin being preferred. Examples of synthetic resins include, but are not limited to, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, polylactic acid, acrylonitrile butadiene styrene (ABS) resin, acrylonitrile styrene (AS) resin, acrylic resin, polyvinyl chloride, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, phenolic resin, melamine resin, urea resin, alkyd resin, epoxy resin, silicone resin, polysulfone, polyethersulfone, polyarylate, polyamideimide, polyetherimide, polyphenylene sulfide, polyetheretherketone (PEEK), and fluororesin.

[0032] The sample holder 100 can be manufactured using known molding techniques, such as, but not limited to, injection molding, press molding, and molding using a 3D printer.

[0033] (Tip) FIG. 5 shows the chip 200 in the taste sensor probe 400 of the present invention. The chip 200 includes a terminal portion 21, a wiring portion 22, and at least one electrode portion 23. The terminal portion 21 connects the chip 200 to the taste sensor device 50. The wiring portion 22 connects the terminal portion 21 and the electrode portion 23 and has the function of transmitting the potential acquired by the electrode portion 23 to the terminal portion 21 as an electrical signal. The electrode portion 23 has a configuration in which a conductor and a lipid membrane 24 are connected to allow charge transfer, and is a portion that detects a change in potential when a taste substance in a sample interacts with the lipid membrane 24 of the electrode portion 23. The potential detected by the electrode portion 23 is transmitted to the terminal portion 21 through the wiring portion 22 and then transmitted to the taste sensor device 50 via the terminal portion 21.

[0034] The chip 200 may include only one electrode unit 23, or may include multiple electrode units 23. When the chip 200 includes multiple electrode units 23, the tastes to be measured by the respective electrode units 23 may all be the same or different. For example, when the chip 200 is provided with six electrode units 23, all of the electrode units 23 may be salty-sensitive, or three electrode units 23 may be salty-sensitive and three electrode units 23 may be sour-sensitive, and the six electrode units 23 may be sweet-sensitive, bitter-sensitive, sour-sensitive, salty-sensitive, umami-sensitive, and astringent-sensitive, respectively.

[0035] (Chip manufacturing method) The chip 200 can be fabricated by a method known in the art, for example, by arranging a conductor on the substrate 20 and then forming a lipid membrane 24 on the portion corresponding to the electrode portion 23.

[0036] substrate The substrate 20 may be made of any material used in the art, provided that it has insulating properties and is strong enough for measurement, such as, but not limited to, glass, plastic, synthetic rubber, ceramics, or water-resistant paper or wood.

[0037] conductor The conductor may be, but is not limited to, a metal such as aluminum, chromium, copper, silver, platinum, or gold, or carbon. Carbon is preferred. Formation of the conductor on the substrate 20 can be achieved by a method commonly used in the art. For example, a carbon paste can be applied to the substrate 20 by screen printing or the like, followed by drying and baking to form a carbon layer on the substrate 20. The conductor layer may also be disposed by sputtering or vapor deposition. Furthermore, at least a portion of the conductor may be coated with a thermosetting resin, an ultraviolet-curing resin, or the like.

[0038] lipid membrane The lipid membrane 24 is formed so as to cover the portion of the conductor corresponding to the electrode portion 23 .

[0039] The lipid membrane 24 may be any lipid membrane 24 known in the art. The lipid membrane 24 is generally obtained by mixing and forming a membrane from a polymer substrate, a plasticizer, and a lipid. The electrode unit 23 can change the type of taste substance it responds to and its sensitivity by changing the compounding ratio of the lipid and plasticizer that form the lipid membrane 24.

[0040] The polymer substrate used for the lipid membrane 24 may be any material that provides sufficient strength to allow a sample to contact the lipid membrane 24 and detect a change in potential. Examples of suitable polymer substrates include, but are not limited to, polyvinyl chloride (PVC), polystyrene, polysulfone, polycarbonate, polyarylate, polyethylsulfone, polysulfone sulfonate, aromatic polyamide, polyglutamate, polyvinyl alcohol, polyacrylonitrile, polyvinyl difluoride, polyethylene urethane, polyvinyl butyral, polyvinyl pyridine, nylon 66, nitrophenyl ether, cellulose acetate, cellulose acetate butyrate, agar, k-carrageenan, sodium alginate, epoxy, poly-p-xylene, polytetrafluoroethylene, and lacquer.

[0041] The plasticizer used in the lipid membrane 24 provides flexibility to the lipid membrane 24. Examples of the plasticizer that can be used include, but are not limited to, phosphate esters, phthalate esters, fatty acid esters, adipate esters, citrate esters, and sebacate esters.

[0042] Any lipid known in the art can be used for the lipid membrane 24. For example, but not limited to, the lipid may be monoalkyl phosphate, dialkyl phosphate, oleylamine, alkylammonium salt, fatty acid, fatty alcohol, cholesterol, lecithin, or the like.

[0043] The lipid membrane 24 can be prepared by a method known in the art, for example, by dissolving a polymer substrate, a plasticizer, and a lipid in an organic solvent, adding the solution dropwise to the portion of the conductor corresponding to the electrode portion 23, and then removing the solvent.

[0044] The mechanism by which a taste substance interacts with the lipid membrane 24 can be mainly divided into electrostatic interaction and hydrophobic interaction. The taste sensor probe 400 of the present invention can be used to measure any taste substance, but is particularly useful for measuring taste substances in which a hydrophobic interaction is mediated in the interaction between the taste substance and the lipid membrane 24. Examples of taste substances in which a hydrophobic interaction is mediated in the interaction with the lipid membrane 24 include, but are not limited to, bitter substances such as tannic acid, quinine hydrochloride, and iso-α acid.

[0045] (reference electrode) The reference electrode is configured to indicate a potential that serves as a reference for measurement when in contact with the sample. The reference electrode may be prepared, for example, as a separate, independent probe (external reference electrode). In the taste sensor, the amount of a taste substance in a sample can be evaluated by measuring the voltage (potential difference) between the indicator electrode (electrode portion) configured using a lipid membrane and the reference electrode.

[0046] (Sealing material) In the taste sensor probe 400 of the present invention, a sealing member may be further used around the second wall 17 of the sample holder 100 to prevent leakage of the sample (FIG. 6(a)). Examples of sealing members that can be used in the taste sensor probe 400 of the present invention include O-rings.

[0047] (fixing jig) The taste sensor probe 400 of the present invention may further include a fixing jig 300 for fixing the sample holder 100 and the chip 200 (FIG. 6(d)). The material forming the fixing jig 300 may be any material that is strong enough to fix the sample holder 100 and the chip 200. Examples of such materials include, but are not limited to, glass, synthetic resin, synthetic rubber, ceramics, or water-resistant paper and wood, with synthetic resin being preferred. The material forming the fixing jig 300 may be the same as or different from the material forming the sample holder 100.

[0048] (How the taste sensor probe is used) 6(a) to 6(d) illustrate examples of the taste sensor probe 400 of the present invention when in use. FIG. 6(a) illustrates the sample holder 100 of the present invention with an O-ring 110 attached as a sealing member. FIG. 6(b) illustrates the chip 200 superimposed on the sample holder 100 so that the electrode section 23 is located in the second region 16. FIG. 6(c) illustrates the taste sensor probe 400 of the present invention in which the sample holder 100 and chip 200 of FIG. 6(b) are fixed by a fixing jig 300. FIG. 6(d) illustrates the taste sensor probe 400 of FIG. 6(c) turned upside down. The taste sensor probe 400 of the present invention is generally used in the orientation shown in FIG. 6(d).

[0049] (Taste sensor device) 7 illustrates a taste sensor system 500 including a taste sensor probe 400 and a taste sensor device 50 of the present invention. The taste sensor device 50 may have any configuration as long as it can be used as a taste sensor. For example, the taste sensor device 50 shown in FIG. 7 includes a display unit 51 and an operation unit 52, and has a built-in control unit and recording unit.

[0050] The taste sensor probe 400 of the present invention can be detachably connected to the taste sensor device 50 via the terminal portion 21. Therefore, the taste sensor probe 400 of the present invention can be made disposable.

[0051] The principle of a taste sensor is to detect the electric potential generated by the interaction between a taste substance and a lipid membrane. While not bound by theory, it is believed that, for example, in a method of dripping a sample onto an electrode, as described in Patent Document 1, the amount of taste substance present in the dripped sample is so small that the interaction with the lipid membrane does not reach equilibrium, resulting in variability in the measurement results. On the other hand, the taste sensor probe of the present invention is equipped with a sample holder, which allows a sufficient amount of sample to contact the electrode so that the interaction between the taste substance and the lipid membrane reaches equilibrium, thereby enabling stable measurements.

[0052] On the other hand, when a fluid is injected into a limited space, the fluid generally undergoes a violent flow. In a taste sensor, such a violent flow of fluid can destabilize the potential at the electrode portion, resulting in variability in the measurement results. However, the sample holder of the present invention has walls that act as barriers to suppress the flow of the sample. Therefore, even when a fluid is injected into a narrow space such as the inside of a sample holder, the potential at the electrode portion can be stabilized in a short time. This not only reduces variability in the measurement results, but also allows measurement results to be obtained in a shorter time. [Example]

[0053] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0054] (Tip) Carbon paste was patterned on a polyethylene terephthalate substrate as a conductor, and the conductor wiring was covered with UV-curable resin. Next, lipid membrane components were dissolved in tetrahydrofuran, dropped onto the electrode, and dried to form a lipid membrane, which was then used as a chip.

[0055] (sample holder) Using a 3D printer, sample holders of the first to fourth embodiments shown in Figures 1 to 4 were fabricated. The sample holders of the first, second, third, and fourth embodiments are hereinafter referred to as E1, E2, E3, and E4, respectively. As a comparative example, a sample holder without walls was fabricated using the same procedure (hereinafter referred to as C1).

[0056] (reference electrode) A commercially available Ag / AgCl glass electrode was used as an external reference electrode.

[0057] (Sample preparation) A sample solution was prepared to have the following composition: Composition of sample solution A Tartaric acid 0.3mM KCl 30mM Composition of sample solution B Tartaric acid 0.3mM KCl 30mM Quinine hydrochloride 0.1mM Composition of sample solution C Tartaric acid 0.3mM KCl 30mM Iso-α-acid 0.01% by volume

[0058] (Example 1: Verification of the effect of injection direction on measurement results) Using sample holders E1 and C1, we investigated the effect of the sample injection direction on the variability of the measurement results. An O-ring was attached to the sample holder (E1 or C1), and the chip was fixed to the sample holder using a fixing jig and connected to the taste sensor device. Next, approximately 1 mL of sample solution B was injected in various directions using a micropipette. The injection direction was changed for each test. After the sample solution was injected, an external reference electrode was inserted through the injection port and the response voltage of each electrode was measured. Tests were performed six times each using E1 and C1. The results are shown as the mean and standard deviation for the electrode (one) that was in front of the pipette tip and the other electrodes (five) (t-test: ** P<0.01). For reference, the results of measuring sample solution A using C1 were also confirmed.

[0059] (result) The results are shown in Figure 8. Sample solution B is a sample in which the interaction between the taste substance and the lipid membrane is mediated by hydrophobic interactions, while sample solution A is a sample in which the interaction between the taste substance and the lipid membrane is not mediated by hydrophobic interactions. When C1 was used, comparing the results for sample solution B and sample solution A, the difference in the results for sample solution B was greater between the electrode positioned in the injection direction and the electrode not. Thus, it was confirmed that in taste sensors, substances that interact with the lipid membrane via hydrophobic interactions tend to produce greater variability in results between electrodes.

[0060] Furthermore, for sample solution B, the difference in results between the electrodes in the injection direction and those in the opposite direction was smaller when sample holder E1 was used than when C1 was used, as shown in Figure 8. This result demonstrates that in the taste sensor probe of the present invention, the sample holder having a wall can reduce the variation in results resulting from the injection direction.

[0061] (Example 2: Verification of the effect of injection speed on measurement results) Tests were conducted under the same conditions as in Example 1, except that sample holders E1 and C1 were used and the sample injection rate was changed. Approximately 1 ml of sample solution B was injected at injection rates of 0.4 ml / sec and 0.2 ml / sec. The injection direction was changed for each test. After sample injection, an external reference electrode was inserted through the injection port and the response voltage of each electrode was measured. Tests were conducted six times each using E1 and C1. The results are shown as the average value and standard deviation for one electrode in the direction of injection of the sample solution and five other electrodes (t-test: * P<0.05, ** P<0.01).

[0062] (result) The results are shown in Figure 9. As shown in Figure 9, for C1, differences in results occurred between the electrodes positioned in the direction of sample solution injection and those not, regardless of the injection speed. Furthermore, the difference in results was particularly significant for the electrodes positioned in the direction of sample solution injection at 0.4 ml / sec and 0.2 ml / sec. On the other hand, when using sample holder E1, nearly consistent results were obtained even when the injection direction and injection speed were changed. These results demonstrate that, in the taste sensor probe of the present invention, the sample holder having a wall can reduce the variability in measurement results resulting from the injection direction and injection speed of the sample.

[0063] (Example 3: Examination of the height of the sample holding area) Sample holders were fabricated in which the height of the second region of the sample holder E1 was varied from 0.5 mm to 3.1 mm (internal dimensions), and the response voltage of each electrode was measured. Aside from varying the height of the second region, the test was conducted in the same manner as in Example 1. Approximately 1 mL of sample solution B was injected through the inlet, and an external reference electrode was inserted through the inlet to measure the response voltage of each electrode. The test was performed three times, but electrode sections with abnormally shaped lipid membranes were excluded from the measurement, so the results are N=2 or N=3.

[0064] (result) Figure 10 is a graph plotting the measurement results for each electrode. For second-zone heights ranging from 0.5 mm to 3.1 mm, the variance in the measurement results was small. Furthermore, the variance between electrodes tended to decrease as the height of the second zone increased. Generally, the narrower the space through which the fluid flows, the faster the flow rate; the wider the space, the slower the flow rate. Therefore, the lower the height of the second zone, the stronger the momentum of the sample flowing through the second zone, which likely led to greater differences in the influence of the sample on each electrode, resulting in variance between electrodes. While not bound by theory, we believe that increasing the height of the second zone reduces the momentum of the sample flowing through the second zone, thereby reducing the influence of the sample momentum on each electrode, thereby reducing variance between electrodes. Furthermore, increasing the height of the second zone, i.e., increasing the volume of sample that can be injected, allows the taste substance to be distributed evenly throughout the second zone, thereby reducing variance between electrodes.

[0065] (Example 4: Examination of the shape of the sample holder) The effect of sample holder structure on the variability of measurement results was investigated using sample holders E1 to E4 with various structures. A chip equipped with a sample holder was connected to a taste sensor device, and approximately 1 mL of sample solution C was injected into the sample holder for either 1 second (1 s) or 5 seconds (5 s). After the sample solution was injected, an external reference electrode was inserted into the injection port and the response voltage of each electrode was measured. As a control, a chip without a sample holder was immersed in the sample solution for either 1 second or 5 seconds (immersion method). Measurements were performed six times for each electrode, with N = 1, for a total of 36, with N = 36. Results are presented as mean values ​​and standard deviations. Additionally, for each sample holder, N = 72 results were calculated, combining the 1-second and 5-second injection times, and the mean values ​​and standard deviations were compared.

[0066] (result) The results are shown in Table 1. When sample holder E1 was used, the difference in the average values ​​for 1 s and 5 s was smaller than with the immersion method, but the variability at N=72 was slightly larger than with the immersion method. For E2, the difference in the average values ​​for 1 s and 5 s was similar to that with the immersion method, but the variability at N=72 was smaller than with the immersion method. For E3 and E4, the difference in the average values ​​for 1 s and 5 s was smaller than with the other sample holders, and the variability at N=72 was also smaller. These results demonstrate that in the taste sensor probe of the present invention, by changing the structure of the sample holder, the variability in measurement results can be reduced compared to the immersion method.

[0067] [Table 1]

[0068] The graph in Figure 11 plots the standard deviation of the response voltage (N = 72) every second. As shown in Figure 11, the standard deviation of the response voltage for E1 gradually decreases from approximately 7 seconds to 40 seconds, whereas for E4, it barely changes from 10 seconds to 40 seconds. This result indicates that when the sample holder for E4 is used for measurement, the response voltage stabilizes in a shorter time than for E1, and therefore, measurements can be made in a shorter time using E4. Furthermore, the absolute value of the standard deviation for E4 is smaller than that for E1, which indicates that measurement using E4 can reduce the variability in results compared to E1. This indicates that the sample holder of the present invention, by changing its structure, not only enables measurements with a small amount of sample, but also has the effect of reducing the variability in measurement results.

[0069] The above results demonstrate that the use of the taste sensor probe of the present invention enables reproducible measurement results even when the sample amount is small. Furthermore, it was shown that further reduction in variability and shortening of measurement time are possible by changing the structure of the sample holder. [Explanation of symbols]

[0070] 100, 101, 102, 103 Sample holder 11 Wall 12 Opening 13 Inlet 14 Air vent 15 First Area 16 The Second Region 17 The Second Wall 18 Injection Guide 110 O-ring 200 chips 20 Substrate 21 Terminal section 22 Wiring section 23 Electrode section 24 Lipid membrane 300 Fixture 400 Taste sensor probe 500 Taste Sensor System 50 Taste sensor device 51 Display section 52 Operation section

Claims

1. A taste sensor probe including a sample holder and a tip, The sample holder is a sample holding area having a first area and a second area; an injection port for injecting a sample into the first region; a wall defining the second region; at least one opening in the wall; At least one air vent provided in the second region; Equipped with The chip is A terminal portion, A wiring section; At least one electrode portion; Equipped with the sample passes through the opening and enters the second region; the first region and the second region are in fluid communication; The electrode portion contacts the sample in the second region.

2. The taste sensor probe according to claim 1 , wherein the sample holding area is surrounded on its outer periphery by a second wall.

3. The taste sensor probe according to claim 2 , wherein the second wall is a part of the sample holder.

4. The taste sensor probe according to claim 2 , wherein the second wall is provided by a member separate from the sample holder.

5. The taste sensor probe according to any one of claims 1 to 4, wherein a wall defining the second region exists on a straight line connecting the injection port and the electrode portion.

6. A taste sensor probe according to any one of claims 1 to 5, wherein a wall defining the second region is provided around the inlet, and defines the first region around the inlet.

7. The taste sensor probe according to any one of claims 2 to 4, wherein the wall defining the second region is connected to the second wall at at least one point.

8. The taste sensor probe according to any one of claims 1 to 5, wherein a plurality of walls defining the second region are provided.

9. The taste sensor probe according to claim 8 , wherein a plurality of the electrode portions are provided, and a plurality of the second regions are provided for each of the electrode portions.

10. The taste sensor probe according to claim 9 , wherein a plurality of the air vent holes are provided for each of the second regions.

11. A taste sensor probe according to any one of claims 1 to 10, wherein at least one of the electrode parts is an electrode part that is sensitive to a taste substance whose interaction with a lipid membrane is mediated by hydrophobic interaction.

12. The taste sensor probe according to any one of claims 1 to 11, wherein the chip comprises a plurality of the electrode portions, and the plurality of electrode portions are configured to respond to at least two types of taste.

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