Electrochemical sensor capable of being swallowed

Abstract

The present invention relates to a swallowable electrochemical sensor which is advantageous in that its housing has an electrolyte inlet through which an aqueous electrolyte, such as stomach acid, can enter the interior of the sensor from around it and be used therein as an electrolyte.

Description

Technical Field

[0001] The present invention relates to an electrochemical sensor that is swallowable and excellent in that it can be used for detecting gas in the human intestinal tract.

[0002] Electrochemical sensors are basically known. They are electrochemical cells having at least one working electrode and a counter electrode, in which, as long as a certain amount of analyte reaches the region of the electrodes, an electric current can flow between the electrodes using a conductive fluid, a so-called electrolyte. The analyte is usually a gas.

[0003] However, a drawback of conventional electrochemical sensors is that the materials usually required for the electrochemical reaction, that is, not only the electrolyte but also the electrodes, are often toxic or at least harmful to organisms.

[0004] In that regard, the use areas of conventional electrochemical sensors are limited.

[0005] Nevertheless, from a medical point of view, the ability to detect specific gases in vivo is significant. Therefore, for example, in the context of inflammatory bowel disease, it can be significant to monitor the generation of H 2 S gas or NO gas. For example, based on the generation of these gases, it may often be possible to predict the severity of the corresponding disease that progresses in a wave-like manner.

[0006] Swallowable sensors are known, for example, from US Patent No. 10,326,139. However, they are often optical sensors or pH sensors. These are only suitable limitedly for gas detection. Optical sensors can be used to detect high concentrations of methane, but it is relatively frequently used for imaging the gastrointestinal tract. In contrast, pH sensors are often used for examining the pH value of the stomach.

[0007] In addition, according to Yoshida, S., Miyaguchi, H. & Nakamura, T. (2018), Proof of Concept for Tablet-Shaped Ingestible Core-Body Thermometer with Gastric Acid Battery. IEEE Sensors Journal; 18(23), 9755-9762; doi: 10.1109 / JSEN.2018.2871064, for example, a battery that can be used for the operation of ingestible electronic devices is known. This battery is also an electrochemical cell. However, in this case, the surface of the electrode in the form of a metal plate is exposed. When this exposed electrode surface comes into contact with gastric juice from the surroundings, it immediately acts as a battery. Here, it is an electrochemical cell with gastric juice as the electrolyte, but it should be noted that there is a fundamental difference between a battery and an electrochemical gas sensor in terms of the general functional method. In that sense, the battery proposed by Yoshida, S., Miyaguchi, H. & Nakamura, T. (2018) is not suitable for gas detection at all.

[0008] Therefore, an object of the present invention is to provide an electrochemical gas sensor that can be used to detect gas in an individual's digestive tract.

[0009] The main features of the present invention are described in the characterizing part of claim 1. Embodiments are the subject of claims 2 to 14.

[0010] An electrochemical gas sensor is proposed that includes a housing, at least one working electrode, and a counter electrode. In this case, the housing has a gas inlet, and the gas inlet is shielded by a gas-permeable membrane. This electrochemical gas sensor is characterized in that the housing has at least one electrolyte inlet, and the electrolyte inlet is filled with a hydrophilic sealing material. This electrochemical gas sensor is preferably an ingestible gas sensor for detecting gas in the human intestinal tract.

[0011] Such a gas sensor can be swallowed by the individual to be examined, and thus this gas sensor reaches the digestive tract. In other words, this is a swallowable sensor device. Then, in the digestive tract, preferably in the stomach, the hydrophilic sealing material can allow gastric juice to reach the inside of the housing, preferably the internal space described below, through the electrolyte inlet. For this purpose, the hydrophilic sealing material is advantageously permeable to aqueous fluids such as gastric juice but does not leak to particles, such as food particles. The gastric juice thus contacts the electrodes, in particular the working electrode and the counter electrode, and as a result, can be used as an electrolyte inside the gas sensor. Thus, when the gastric juice flows in through the electrolyte inlet, an electrochemical gas sensor that can function completely inside the body of the individual after swallowing the device according to the invention is produced. In other words, the device according to the invention can also be referred to as a swallowable electrochemical instant gas sensor. This provides a great advantage that the use of conventional electrolytes, in particular toxic and / or harmful electrolytes, can be omitted when operating the electrochemical gas sensor inside the body of the individual to be examined by using the device according to the invention. This is a great advantage of the present invention.

[0012] In any case, the housing is a hollow body having an outer surface and an internal space. Components of the electrochemical cell are arranged in the internal space. In addition, in the standby state, gastric juice used as an electrolyte is arranged in the internal space.

[0013] Here, it is advantageous if the housing also has a gas inlet different from the electrolyte inlet. Then, through this gas inlet, the gas to be detected can reach the electrochemical cell and subsequently be replaced at the working electrode.

[0014] It can be seen that it is advantageous as long as the housing has a plurality of openings, that is, at least one gas inlet and at least one electrolyte inlet. The gas inlet is a hole in the wall of the housing through which gas can penetrate into the internal space of the housing. In order to prevent fluid from penetrating through the gas inlet, it is significant if the gas inlet is shielded by a membrane that is gas permeable but forms a barrier against fluids and particles. The electrolyte inlet is also a hole in the wall of the housing.

[0015] Then, in the internal space, the gas can come into contact with the working electrode and the electrolyte flowing in through the electrolyte inlet, whereby an electrochemical reaction occurs as a result. Due to this electrochemical reaction, current flows between the working electrode and the counter electrode. Then, this current flow becomes detectable.

[0016] In order to detect the electrochemical reaction, a measuring electronic device is preferably arranged in the housing, preferably in an electronic device space separate from the internal space. This measuring electronic device is connected to an electrode arranged in the internal space of the electrochemical cell via a noble metal wire. This may be configured to transmit a measurement signal wirelessly, for example via Bluetooth (registered trademark) or equivalent wireless signal transmission, to a receiver arranged outside the body of the individual who has swallowed the sensor.

[0017] The electrolyte inlet is an opening in the housing of the electrochemical sensor. This opening connects the inside of the housing to the surroundings outside the electrochemical sensor. Through the opening, fluid, preferably gastric juice, can flow into the inside of the housing.

[0018] The hydrophilic sealing material is, for example, glass non-woven fabric, hydrophilic PTFE (polytetrafluoroethylene)-functionalized PO (polyolefin), etc. The hydrophilic sealing material absorbs gastric juice from around the sensor due to its hydrophilic property. However, at the same time, it prevents relatively large particles from reaching the inside of the housing. In that regard, this sealing material allows gastric juice to be conveyed into the inside of the housing through the electrolyte inlet.

[0019] In other words, the present invention relates to a swallowable electrochemical sensor, the housing of which has an electrolyte inlet through which an aqueous electrolyte, such as gastric acid, can penetrate from the surroundings of the sensor into the interior, where it is used as an electrolyte, and in that respect it is excellent. In that regard, this electrochemical sensor shifts to a standby state upon swallowing and the penetration of gastric acid.

[0020] In a first variant embodiment, it is assumed that the internal space of the housing is filled with a hydrophilic filler. This hydrophilic filler can then act as a core for transporting gastric juice from the external environment of the swallowed sensor to the electrodes as desired. The hydrophilic filler can also be made of the same material as the hydrophilic sealing material. In this way, it is possible to ensure not only that gastric juice, which functions as an electrolyte, is sucked into the electrolyte inlet, but also that the interior of the housing is actually filled. In addition, by using a core made of such a hydrophilic filler, it is possible to ensure that a three-phase boundary necessary for an electrochemical reaction for gas detection is properly formed. Therefore, the core formed of the hydrophilic filler and filling the interior of the housing ensures that the electrolyte is transported from the outside through the electrolyte inlet to the electrodes sufficiently but not excessively. Here, the hydrophilic filler is preferably designed such that the transport of the electrolyte is affected not only by the hydrophilicity of the material but also by capillary forces. The strength of the acting capillary forces can be influenced, for example, by the selection of the pore size of the filler. It has been found that glass fiber systems, such as glass fiber nonwovens, are particularly suitable here.

[0021] In addition, it is conceivable that the housing has a plurality of electrolyte inlet openings. This offers the advantage that there are multiple possibilities for gastric juice to flow into the internal space of the housing. In this way, it is ensured that sufficient gastric juice can reach the internal space of the housing even if one of the inlet openings is blocked by food particles or the like. Here, it is also conceivable to fill all the openings and the entire capsule with hydrophilic fibers.

[0022] It can be seen that it is advantageous if the sensor is a capsule. Here, a capsule is generally understood to mean a more or less small, circular container that can be used to transport the object to be protected. Such a container usually has a housing, and the object to be transported is arranged inside it. Here, the housing of the capsule can form the housing of the electrochemical sensor, and the remaining structural parts of the sensor correspond to the following embodiments already described above. Alternatively, it is also conceivable that the sensor is tablet-shaped. In any case, the sensor can be referred to as a capsule-type sensor.

[0023] The housing can be considered to be made of an inert plastic. For example, the housing may be manufactured from medically usable polypropylene or polyethylene. An inert material reacts only to a very small extent, preferably not at all, with the surrounding reagents and substances. It can be seen that it is particularly advantageous in this regard if the inert plastic is inert to gastric juice. An inert plastic to gastric juice is inert particularly to hydrochloric acid and digestive enzymes.

[0024] In addition, the sensor may have a soft inert material as an outer shell. Such an outer shell may be adhered to the outer surface of the housing, for example, as a coating. This outer shell can be used to improve the swallowability of the sensor. For example, it is conceivable that the outer shell is made of silicone or other medically inert materials. A medically inert material here is, for example, a material that does not react with body fluids such as gastric juice or other digestive fluids, and as such is not absorbed by the body and is excreted again as it is. As long as the outer shell is formed from a correspondingly resistant inert material, it is of course formed so that the inlet openings of the housing, i.e., the gas inlet and the electrolyte inlet, are not shielded.

[0025] Alternatively, the sensor may have an outer shell made of a soft and absorbable material. Such a soft and absorbable material may be, for example, gelatin. Such an outer shell can further improve the swallowability of the sensor. The absorbable material can be dissolved, for example, by gastric juice. In this case, it is also possible for the outer shell to first cover the inlet opening of the housing. This may be advantageous, for example, for the manufacturing process. Then, the sensor only needs to be simply immersed completely in gelatin.

[0026] In any case, it is significant if the gas inlet is present immediately before the working electrode. In this way, a section can be slightly retained in which the gas has to travel through the interior of the sensor until it is replaced at the working electrode. It is advantageous if a hydrophobic membrane is arranged in front of the gas inlet and in front of the working electrode. Such a membrane, on the one hand, is used as a physical barrier and can prevent the ingress of food particles. On the other hand, the hydrophobic membrane can prevent the ingress of gastric juice through the gas inlet. The hydrophobic membrane may form narrow pores to additionally make it difficult for substances other than gas to enter. The membrane with narrow pores is here understood to mean a membrane with a pore diameter of at most 5 μm. It is advantageous if the pore diameter is less than 5 μm, preferably less than 4 μm, particularly preferably less than 3 μm, and most preferably less than 2 μm.

[0027] In addition to the working electrode and the counter electrode, the sensor can further have a reference electrode. This reference electrode is also arranged within the internal space of the housing and thus is also in conductive contact with the electrolyte in the same way. This electrode can be used to calibrate and test the functionality of the sensor according to the present invention. Therefore, this is particularly advantageous since a swallowed sensor cannot be easily accessed from the outside for its own calibration or maintenance.

[0028] In any case, the electrode material may be selected from palladium, platinum, rhodium, iridium, carbon, and / or gold. Mixtures from the materials described above are also conceivable. In particular, carbon and gold here offer the additional advantage of being inert materials. The remaining electrode materials can also be used without problems based on the structural form of the sensor according to the invention. This is because the remaining electrode materials are present exclusively inside the sensor and thus cannot come into contact with body tissue. The structural form of the sensor as an encapsulated sensor can be seen to offer further advantages in this regard.

[0029] Here, it is also conceivable that there are two working electrodes. This is advantageous, for example, when a plurality of different gases are to be detected. For this purpose, for example, the first working electrode may be made of iridium. Such an iridium electrode can be selectively used for the detection of H 2 S. The second working electrode may be made of carbon. The carbon electrode can then be selectively used for the detection of NO. Thus, if a sensor having a first working electrode made of iridium and a second working electrode made of carbon is included, it can be used for the selective detection of H 2 S and NO. This is useful, for example, when it is necessary to detect the inflammatory waveform that is beginning during the course of ulcerative colitis.

[0030] In one variant embodiment, it is conceivable that the sensor can be filled with an electrolyte, where the electrolyte is selected from the group comprising citric acid, formic acid, acetic acid, hydrochloric acid, or phosphoric acid. Here, this sensor may in particular be fillable with an electrolyte before swallowing. For this purpose, the electrolyte-free sensor provided is placed in an electrolyte bath. This electrolyte bath consists of a solution of, for example, citric acid, formic acid, acetic acid, etc. It is particularly advantageous when the electrolyte bath consists of a citric acid solution. Citric acid is preferably an aqueous solution, in which case citric acid is present in a concentration range of 0.1 mol to 2 mol, preferably 0.5 mol to 1 mol, and particularly preferably 0.75 mol. In a further variant embodiment, it is particularly advantageous when the electrolyte bath consists of a hydrochloric acid solution. The hydrochloric acid solution is an aqueous solution, in which case hydrochloric acid is present in a concentration range of 0.1 mol to 2 mol, preferably 0.5 mol to 1 mol, and very preferably 1 mol. Of course, it is understood that even a slight tolerance in the concentration range also belongs to the corresponding embodiments. In another further variant embodiment, it is particularly advantageous when the electrolyte bath consists of a phosphoric acid solution. The phosphoric acid solution is an aqueous solution, in which case phosphoric acid is present in a concentration range of 0.1 mol to 2 mol, preferably 0.5 mol to 1 mol, and very preferably 1 mol. Of course, here too, it is understood that even a slight tolerance in the concentration range belongs to the corresponding embodiments.

[0031] It can be seen that, in the spirit of the solution means of the present invention, a method for providing a swallowable electrochemical sensor also has advantages. In this case, the method comprises the following steps: a. providing an unfilled electrochemical sensor; b. providing an electrolyte solution; c. immersing the unfilled electrochemical sensor in the electrolyte solution; d. providing a pre-filled electrochemical sensor and includes.

[0032] Optionally, the sensor can also be coated between steps c and d, i.e., after being pre-filled by immersion in the electrolyte solution and before being provided for swallowing. For example, here, the coating with gelatin already described above can be applied. Other coatings are of course also conceivable. In that case, the method comprises the following step e: e. The method can also include coating the pre-filled sensor (10) with a layer that self-decomposes upon contact with gastric acid.

[0033] Step e is preferably carried out after step c but before step d.

[0034] In any case, pre-filling the electrochemical sensor according to step c is advantageous if it also includes a short flushing of the sensor after immersion of the non-filled electrochemical sensor. This flushing can be carried out, for example, by a short flushing under running water immediately before swallowing. However, it is preferred to briefly immerse the sensor immersed in the electrolyte solution in a flushing bath. This flushing bath can contain, for example, distilled water or physiological saline.

[0035] Particularly preferably, the electrolyte bath provided corresponding to step b has an electrolyte selected from the group consisting of citric acid, formic acid, acetic acid, hydrochloric acid, phosphoric acid, preferably citric acid, formic acid, hydrochloric acid or phosphoric acid, and most preferably citric acid, hydrochloric acid or phosphoric acid.

[0036] Here, for example, it is conceivable first to make the non-filled sensor available to a medical or pharmaceutical professional. Subsequently, the steps necessary to pre-fill it and the coating of the sensor are then carried out. Here, the coating can be carried out, for example, by immersing the sensor in a pre-filled gelatin solution or the like. Subsequently, the professional can then hand the sensor thus prepared to the patient, who then swallows it.

[0037] Subsequently, after swallowing, in addition to the electrolyte already present in the sensor, gastric acid, as already described above, can flow into the sensor through one or more electrolyte inlets.

[0038] Accordingly, in a further advantageous variant embodiment, the solution to the problem also includes a kit for detecting intestinal gas, in which case the kit has an unfilled electrochemical sensor corresponding to the above-described content, as well as an electrolyte preparation.

[0039] Here, it is conceivable that the electrolyte preparation is present as an immediately usable fluid preparation, a concentrated fluid preparation, or a powder. By using this kit, medical or pharmaceutical personnel, or the patient himself / herself, can appropriately pre-fill the swallowable electrochemical sensor immediately before use. If the electrolyte preparation is present as a powder, this electrolyte preparation can be dissolved, for example, with an appropriately pre-set amount of fluid. For example, it can be dissolved with an appropriately pre-set amount of tap water or distilled water in the instruction manual. If the electrolyte preparation is present as a concentrated fluid preparation, this electrolyte preparation can be diluted until the desired use concentration is achieved according to the instructions in the instruction manual before immersing the unfilled sensor in the electrolyte preparation.

[0040] Moreover, such a kit can also provide a corresponding flushing solution. It is also conceivable that the kit includes a corresponding container and can provide a flushing solution for immersing the electrolyte preparation and the sensor in the container.

[0041] Further features, details, and advantages of the present invention will become apparent from the language of the claims and the description of the embodiments based on the following drawings.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3

[0043] In addition to FIG. 1, a cross-sectional view of the gas sensor 10 can also be understood in FIG. 2. This gas sensor 10 has a housing 11. The housing 11 has an internal space 20. Inside the internal space 20, a first working electrode 14 and a second working electrode 14' are arranged. Embodiments having only one working electrode 14 are also conceivable. Further, inside the internal space 20, a counter electrode 15 and a reference electrode 16 are arranged.

[0044] An electronic unit 21 is arranged on the outer surface of the housing 11. This electronic unit 21 is sealed with a leak-proof capsule. The electrodes 14, 14', 15, 16 are connected to the electronic unit 21 via wire connections 22 that are drawn out from the electronic unit 21 and guided through the housing 11 as can be seen particularly in FIG. 2. This wire connection is not visible for all the electrodes in FIGS. 1 and 2. This is because this wire connection is partially outside the cross-section of the figure. However, of course, there is a corresponding wire connection 22 for each of these electrodes.

[0045] It can be seen that the housing 11 has a plurality of openings, namely an opening used as a gas inlet 12 and an opening used as an electrolyte inlet 17.

[0046] The gas inlets 12 are each arranged such that the working electrodes 14, 14' are present immediately behind the gas inlets 12 inside the housing 11. Additionally, each gas inlet 12 is shielded by a hydrophobic membrane 13. In this way, gas can penetrate into the sensor exclusively through the gas inlets 12 and reach the working electrodes 14, 14'. The aqueous fluid is discharged based on the hydrophobic properties of the membrane. Solid particles, such as food particles, are prevented from penetrating by the physical barrier action of the membrane. In the examples shown in FIGS. 1 and 2, the hydrophobic membrane 13 is present on the outer surface of the housing 11. Although it is also conceivable that the hydrophobic membrane 13 is arranged inside the housing 11, in that case, the embodiment shown in the drawings is preferred. Furthermore, in FIGS. 1 and 2, it can be seen that the hydrophobic membrane 13 covers all the gas inlets 12. Of course, here it is also conceivable that each gas inlet 12 is shielded by a single hydrophobic membrane 13, and in this case as well, the variant embodiment shown in the figures is preferred here.

[0047] Openings used as electrolyte inlets 17 are each provided with a hydrophilic sealing material 18. These hydrophilic sealing materials 18 guide the aqueous fluid into the internal space 20 of the housing 11 based on their hydrophilic properties. However, these hydrophilic sealing materials 18 also prevent, similar to the hydrophobic membrane 13, the possibility that solid particles reach the internal space 20.

[0048] The internal space 20 of the housing 11 is further filled with a hydrophilic filler 19. This acts like a sponge or a core and can thus assist, for example, in the penetration of gastric acid used as an electrolyte in this way. Furthermore, the hydrophilic filler 19 can hold the electrolyte that has successfully penetrated into the internal space 20 of the housing 11.

[0049] Furthermore, in FIGS. 1 and 2, it can be seen that the entire device 10 is surrounded by an outer shell 30. The outer shell 30 forms a capsule around the sensor 10. This outer shell 30 is made of, for example, a soft inert material as described above. It can be seen that the outer shell 30 also surrounds a hydrophobic membrane. The outer shell 30 also has through openings only at the locations where the gas inlet 12 and the electrolyte inlet 17 are formed.

[0050] In FIG. 3, it can be seen that a correspondingly swallowable electrochemical sensor can be provided with the sensor 10 not filled in the first step a. This unfilled sensor 10 corresponds to the above-described sensor 10 described above and shown in FIGS. 1 and 2. In that regard, for all the features of the unfilled sensor 10 provided, reference is made to what has been described above in order to avoid repetition. In a further step b, an electrolyte solution is provided. This electrolyte solution can have, for example, citric acid, formic acid, or acetic acid as the electrolyte. Next, the unfilled sensor 10 provided according to step c of the method is immersed in the provided electrolyte solution. Here, the sensor is pre-filled with the corresponding electrolyte. In any case, before being provided for further use according to step d, the sensor 10 pre-filled in this way can be optionally coated as required according to step e.

[0051] In a preferred embodiment, the electrolyte solution provided according to step b is an aqueous solution of 0.75 mol of citric acid.

[0052] In a further embodiment, the electrolyte solution provided according to step b is an aqueous solution of 1 mol of hydrochloric acid.

[0053] In another further embodiment, the electrolyte solution provided according to step b is an aqueous solution of 1 mol of phosphoric acid.

[0054] The present invention is not limited to one of the foregoing embodiments and can be variously modified.

[0055] All features and advantages obtained from the claims, the description, and the drawings may be essential to the invention not only in themselves, including structural details, spatial arrangements, and method steps, but also in various combinations.

[0056] In any case, an electrochemical sensor 10 is provided with a housing 11, at least one working electrode 14, and a counter electrode 15. Here, the housing 11 has an internal space 20 in which the working electrode 14 and the counter electrode 15 are arranged. Here, the housing 11 has at least one gas inlet 12. Here, each gas inlet 12 is shielded by a gas-permeable membrane 13. In the case of the electrochemical sensor 10, it is assumed that the housing 11 has at least one electrolyte inlet 17, and here, each electrolyte inlet 17 is filled with a hydrophilic sealing material 18. Here, it is advantageous when the internal space 20 of the housing 11 is filled with a hydrophilic filling material 19 and / or when the housing 11 has a plurality of electrolyte inlet openings 17. Also, when the sensor 10 is a capsule, it is advantageous when the housing 11 is made of an inert plastic and / or when the sensor 10 has a soft inert material as an outer shell 30. Here, for the purpose, the gas inlet 12 is present immediately before the working electrode 14, and here, a hydrophobic membrane 13 is arranged in front of the gas inlet 12.

[0057] Furthermore, it is advantageous when the sensor 10 has a reference electrode 16. Here, this electrode material may be selected from palladium, platinum, rhodium, iridium, carbon, and / or gold. Preferably, two working electrodes 14, 14' are present. Here, the first working electrode 14 may be made of iridium. The second working electrode 14' may be made of carbon.

Description of Reference Numerals

[0058] 10 Gas sensor 11 Housing 12 Gas inlet 13 Hydrophobic membrane 14 Working electrode 14' Working electrode 15 Counter electrode 16 Reference electrode 17 Electrolyte inlet 18 Hydrophilic sealing material 19 Hydrophilic filler 20 Internal space 21 Electronic unit 22 Wire connection part 30 Outer shell

Claims

1. A swallowable electrochemical sensor (10) for detecting gas in the human intestinal tract, comprising a housing (11), at least one working electrode (14), and a counter electrode (15), wherein the housing (11) has an internal space (20) in which the working electrode (14) and the counter electrode (15) are disposed, the housing (11) has at least one gas inlet (12), in the electrochemical sensor, each gas inlet (12) is shielded by a gas-permeable membrane (13), the housing (11) has at least one electrolyte inlet (17), and each electrolyte inlet (17) is filled with a hydrophilic sealing material (18).

2. The electrochemical sensor according to claim 1, wherein the internal space (20) of the housing (11) is filled with a hydrophilic filling material (19).

3. The electrochemical sensor according to claim 1, wherein the housing (11) has a plurality of electrolyte inlet openings (17).

4. The electrochemical sensor according to claim 1, wherein the sensor (10) is a capsule.

5. The electrochemical sensor according to claim 1, wherein the housing (11) is made of an inert plastic.

6. The electrochemical sensor according to claim 1, wherein the sensor (10) has a soft inert material as an outer shell (30).

7. The electrochemical sensor according to claim 1, wherein the gas inlet (12) is present immediately before the working electrode (14).

8. The electrochemical sensor according to claim 1, wherein a hydrophobic membrane (13) is disposed in front of the working electrode (14) and in front of the gas inlet (12).

9. The electrochemical sensor according to claim 1, wherein two working electrodes (14, 14') are provided.

10. The sensor is fillable with an electrolyte, and the electrolyte is selected from the group comprising citric acid, formic acid, acetic acid, hydrochloric acid, and phosphoric acid.

11. The internal space (20) of the housing (11) is filled with a hydrophilic filling material (19), and the housing (11) has a plurality of electrolyte inlet openings (17).

12. The electrochemical sensor according to claim 1, wherein the gas inlet (12) is present immediately before the working electrode (14), and a hydrophobic membrane (13) is disposed in front of the working electrode (14) and in front of the gas inlet (12).

13. In a method for providing a swallowable electrochemical sensor corresponding to any one of claims 1 to 12, the method comprises the following steps: a. providing an unfilled electrochemical sensor (10); b. providing an electrolyte solution; c. immersing the unfilled electrochemical sensor (10) in the electrolyte solution; d. providing a pre-filled electrochemical sensor (10) The method is characterized by including these steps.

14. The method further comprises the following steps: e. coating the pre-filled sensor (10) with a layer that self-decomposes upon contact with gastric acid, according to the method of claim 13.

15. The electrolyte bath provided corresponding to step b has an electrolyte selected from the group consisting of citric acid, formic acid, acetic acid, hydrochloric acid, phosphoric acid, preferably citric acid, formic acid, hydrochloric acid or phosphoric acid, and most preferably citric acid, hydrochloric acid or phosphoric acid, according to the method of claim 13.

16. A kit for detecting intestinal gas, the kit comprising an unfilled electrochemical sensor corresponding to at least one of claims 1 to 12, and an electrolyte preparation.

17. The electrolyte preparation is present as an immediately usable fluid preparation, a concentrated fluid preparation, or a powder, according to the kit of claim 16.

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