Transdermal alcohol sensor

Abstract

The present invention provides a transdermal alcohol sensor, wherein the sensor comprises: a sensor assembly encapsulated in a housing; a sample inlet channel arranged in the housing, the sample inlet channel being used to provide a channel for providing vapor from body perspiration from the outside of the housing to the sensor assembly; electrical contacts connected to the sensor assembly, being used to transmit an electrical signal generated by the sensor assembly indicating potential alcohol contained in the vapor; and a separate exhaust passage, the exhaust passage being connected from the sensor assembly and being used to allow the vapor to escape into the atmosphere.

Description

Technical Field

[0001] The present invention relates to an electrochemical sensor, and more particularly to a transdermal alcohol sensor. Background Art

[0002] In recent years, the application scenario of measuring blood alcohol directly through the skin (transdermal) has attracted attention. This method does not require the active participation of the subject and may be installed for a long time, requiring the device to serve for intervals of up to three months. A typical application scenario is a recidivist alcoholic who is subject to court.

[0003] The leading devices on the market are transplants of known electrochemical breathalyser technology and are usually complete breathalyser kits that include a pump sampling system, usually attached to the leg and thus somewhat bulky. Although these devices are often described as "continuous" analyzers, they actually sample at intervals, usually 30 minutes.

[0004] A much more compact device that could perform truly continuous analysis would be advantageous. Summary of the invention

[0005] This Summary is provided to introduce some concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0006] The present invention provides a compact diffusion sensor for transdermal measurement of blood alcohol that can provide continuous analysis for more than six months.

[0007] According to one embodiment of the present invention, a transdermal alcohol sensor is provided, wherein the sensor comprises:

[0008] a sensor assembly enclosed in a housing;

[0009] a sample inlet passage disposed in the housing, the sample inlet passage being used to provide a passage for vapor from body perspiration to be provided from outside the housing to the sensor assembly;

[0010] an electrical contact connected to the sensor assembly for transmitting an electrical signal generated by the sensor assembly indicative of potential alcohol contained in the vapor; and

[0011] A separate exhaust passage is connected from the sensor assembly for allowing the vapor to escape to the atmosphere.

[0012] According to a further embodiment of the present invention, the sensor further comprises an outer protective membrane on the housing for protecting the sample inlet channel from the ingress of solid and liquid particles contained in the vapor.

[0013] According to a further embodiment of the present invention, the sensor further comprises an inner protective film located between the sample inlet channel and the sensor assembly, for preventing the sample inlet channel from being blocked by free liquid formed in the sensor.

[0014] According to a further embodiment of the present invention, the sensor further comprises a diffusion control medium for controlling the diffusion rate of vapor entering the sensor.

[0015] According to a further embodiment of the present invention, the sensor further comprises a filter device placed in the exhaust passage for preventing reactive gas from contacting the sensor via the exhaust passage.

[0016] According to a further embodiment of the present invention, the sensor component comprises an electrode and an electrolyte, wherein the electrode comprises two electrodes or comprises three or more electrodes.

[0017] According to a further embodiment of the present invention, the electrolyte comprises sulfuric acid or phosphoric acid.

[0018] According to a further embodiment of the invention, the electrolyte is contained in an electrolyte accumulation wafer.

[0019] According to a further embodiment of the invention, the exhaust passage comprises a vapor exhaust collector arranged below the sensor assembly, an outlet in the housing leading to an exhaust chamber, and a hydrophobic exhaust plug or a hydrophobic membrane.

[0020] According to a further embodiment of the invention, the sample inlet channel is a well, a capillary or a membrane.

[0021] These and other features and advantages will become apparent by reading the following detailed description and by reference to the associated drawings.It is to be understood that the foregoing general description and the following detailed description are illustrative only and are not restrictive of the aspects of what is claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to understand the manner in which the above features of the present invention are used in detail, the above briefly summarized contents can be described in more detail with reference to various embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only show some typical aspects of the present invention and should not be considered to limit its scope, because the description may allow for other equally effective aspects.

[0023] Figure 14 is a structural block diagram of a transdermal alcohol sensor according to an embodiment of the present invention.

[0024] Figure 2 According to one embodiment of the present invention, Figure 1 A cross-sectional view of the transdermal alcohol sensor. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below in conjunction with the accompanying drawings, and the features of the present invention will be further revealed in the following specific description.

[0026] The basic design of an electrochemical diffusion sensor has been established for decades. Electrodes (typically two or three) are enclosed in a sealed container and the rate of exposure to one or more target gases is controlled by the diameter of the membrane, or pores, or capillaries leading to the sensing electrodes. The electrodes are immersed in an ionically conductive electrolyte, usually an acid. The breathalyser sensor is always a two-electrode cell with an acid electrolyte, similar to a diffusion sensor, but differs in that it takes a pumped sample on the order of 0.5 ml.

[0027] In the present invention, in order to reduce the volume of the entire transdermal product kit, the two-electrode, acidic electrolyte mode of the breath analyzer is applied to the diffusion sensor, eliminating the need for a sampling pump and providing true continuous measurement. However, the acidic electrolyte introduces a problem, and providing compensation for this problem is one of the purposes of this application. Acids are selected in part because they can retain moisture, so the electrolytes of the breath analyzer sensor will never dry out. Their water content will certainly change to a certain extent with the ambient temperature and humidity at the time, and it is this characteristic that poses a problem when implementing a diffusion-based transdermal alcohol sensor because the electrolyte is always in close contact with the warm and humid environment (on the order of 35°C and 95% relative humidity) generated by human sweat. In this case, the electrolyte will continue to absorb water vapor, eventually flooding the sensor, which may cause failure, leakage and injury.

[0028] The essential innovation of the present invention is to provide a compact transdermal alcohol sensor that provides a large escape path for water vapor from the sensor and ultimately to the atmosphere to maintain the required acid / water balance in the electrolyte.

[0029] Figure 1 is a structural block diagram of a transdermal alcohol sensor (100) according to an embodiment of the present invention, and Figure 2 yes Figure 1 Cross-sectional view of a transdermal alcohol sensor.

[0030] like Figure 1As shown in , the transdermal alcohol sensor (100) (hereinafter referred to as "sensor (100)") has an integrated housing including a substantially rectangular main body and two cylindrical extensions located on opposite sides of the main body. One of the extensions can be used to accommodate a current collector (3), while the other extension is configured as an exhaust chamber (4), both of which will be further described in more detail below. Those skilled in the art should understand that the rectangular and cylindrical shapes mentioned above are merely examples, and the main body and the extension of the housing can have other suitable shapes according to actual needs.

[0031] The sample inlet channel (2) is disposed on the top surface of the housing and is covered with an outer protective film (1), such as a protective gas permeable membrane. As non-limiting examples, the sample inlet channel (2) may be a hole, a capillary, or a membrane. The function of the outer inlet protective film (1) is to prevent solid and liquid particles contained in the sample from passing through the sample inlet channel (2). In this example, the sample is steam from the skin, which may include water vapor and potential alcohol vapor components. In the sample inlet channel (2) is Figure 1 and Figure 2 In the example of the hole shown in , the hole is arranged in a disk diffusion control medium, which can control the diffusion rate of the vapor molecules, such as by controlling the diameter of the hole (2). As an example, the sample inlet passage (2) can be a capillary tube.

[0032] At the other end of the sample inlet channel (2) is an inner inlet protection membrane (6) which prevents free liquid formed in the sensor (100) from clogging the sample inlet channel (2).

[0033] Below the inner inlet protective membrane (6) is the sensor assembly (or sensor sub-assembly) of the sensor (100). The sensor assembly consists of an electrode-bearing wafer (8) and a catalytic sensing electrode (7) and a catalytic counter electrode (9) respectively arranged on the upper and lower surfaces of the wafer (8). The catalytic sensing electrode (7) and the catalytic counter electrode (9) are both made of electrocatalytically active materials, wherein the catalytic sensing electrode (7) is a sensing anode and the catalytic counter electrode (9) is a cathode. The electrical contacts (e.g., contact wires) of the current collector (3) are connected to the catalytic sensing electrode (7) and the catalytic counter electrode (9) for detecting the electrical signal generated by the reaction at the anode due to the alcohol contained in the sample.

[0034] Below the sensor assembly, more specifically below the catalytic counter electrode (9) is an electrolyte reservoir wafer (10) which covers the side walls of the vapor exhaust collector (11). The electrode carrier wafer (8) and the electrolyte reservoir wafer (10) together form a bipolar electrolyte management system.

[0035] exist Figure 1In the illustrated example, an outlet (12) leading to the exhaust chamber (4) is arranged on one of the side walls of the accumulator (11). As a non-limiting example, the exhaust chamber (4) is arranged near an edge of the main rectangular parallelepiped of the housing. Accordingly, the outlet (12) can be arranged at a corner of the accumulator (11) to align with the exhaust chamber (4). The exhaust chamber (4) can be plugged with an exhaust plug (5). Preferably, the exhaust plug (5) is hydrophobic. The accumulator (11), the outlet (12) and the exhaust plug (5) thus form a separate exhaust passage leading from the sensor assembly, allowing steam to escape into the atmosphere. In an alternative embodiment, the exhaust plug (5) can be replaced by a hydrophobic membrane.

[0036] In operation, the components of the above-described transdermal alcohol sensor (100) may work as follows.

[0037] The sample vapor from the skin (which may include water vapor and potentially alcohol vapor) passes through the outer protective membrane (1), while solid and liquid particles in the vapor are excluded. The vapor then passes through the sample inlet channel (2) and the inner protective membrane (6) and reaches the sensor assembly, more specifically, the catalytic sensing electrode (7) which serves as the sensing anode. In this illustrated example, the sensor assembly includes two electrodes. However, it will be appreciated by those skilled in the art that the sensor assembly may include three or more electrodes.

[0038] Any alcohol that reaches the anode will react with the anode material and generate an electrical signal, such as a current signal. The electrical signal will flow to an external monitoring device, such as a metering device, via the contact wire of the collector (3). The reaction between the alcohol and the anode can refer to the alcohol being essentially oxidized into carbon dioxide and water. Carbon dioxide can leave through the inner protective membrane (6) and the sample inlet channel (2) and return to the atmosphere, while water is isolated by the inner protective membrane (6) to avoid clogging of the sample inlet channel (2) by water. Alternatively, water is dissolved in the electrolyte in the electrolyte accumulation chip (10). As a non-limiting example, the electrolyte may include sulfuric acid or phosphoric acid.

[0039] At all times during service, water vapor from the subject's sweat will be present, which will also dissolve in the electrolyte, diluting it. Excess water will gradually diffuse through the sensor assembly to balance the concentration throughout the electrolyte.

[0040] The humidity at the rear of the sensor assembly (due to the connection to the atmosphere) will be lower than at the front, allowing excess water to evaporate from the electrolyte into the vapor exhaust collector space (11). In an optional embodiment, if necessary, a filter device can be integrated into the vapor exhaust collector space (11) to prevent the entry of active gases. For example, in order to prevent the entry of electrochemically active substances from the atmosphere through the passage to the internal sensor components in the reverse direction, a common chemical filter material can be used. In addition, since the electrolyte accumulation chip (10) forms a wall between the exhaust collector space (11) and the sensing electrode, the electrolyte accumulation chip (10) itself is a filter for water-soluble gases entering the sensing electrode from the exhaust passage.

[0041] From the steam exiting the collector space (11), evaporated water can pass through the outlet (12) and through the exhaust plug (5) into the atmosphere.

[0042] Based on the above structure, the transdermal alcohol sensor of the present invention provides a discharge path for water vapor from the sensor to the atmosphere to maintain the required acid / water balance in the electrolyte. The passage leading to the passage is positioned so that water vapor from the skin and any accompanying alcohol vapor cannot directly reach the passage, and the subsequent discharge path starting from this passage starts from the sensor component to the outside of the device.

[0043] Under conditions simulating continued attachment to the human body, no loss of activity in alcohol detection was observed in this device for a period of more than six months.

[0044] What has been described above includes examples of various aspects of the claimed subject matter. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of describing the claimed subject matter, but one of ordinary skill in the art will recognize that many further combinations and permutations of the claimed subject matter are possible. Thus, the disclosed subject matter is intended to encompass all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A transdermal alcohol sensor, wherein the sensor comprises: a sensor assembly enclosed in a housing; a sample inlet passage disposed in the housing, the sample inlet passage being used to provide a passage for vapor from body perspiration to be provided from outside the housing to the sensor assembly; an electrical contact connected to the sensor assembly for transmitting an electrical signal generated by the sensor assembly indicative of potential alcohol contained in the vapor; and a separate exhaust passage connected from the sensor assembly, the sensor assembly including an electrode and an electrolyte, wherein the exhaust passage includes a vapor exhaust collector disposed below the sensor assembly, an outlet in the housing leading to an exhaust chamber, and a hydrophobic exhaust plug or hydrophobic membrane for allowing vapor evaporated from the electrolyte into the vapor exhaust collector to escape to the atmosphere via the exhaust passage.

2. The sensor according to claim 1, characterized in that The sensor further includes an outer protective membrane on the housing for protecting the sample inlet channel from ingress of solid and liquid particles contained in the vapor.

3. The sensor according to claim 1, characterized in that The sensor further includes an inner protective film located between the sample inlet channel and the sensor assembly, for preventing the sample inlet channel from being blocked by free liquid formed in the sensor.

4. The sensor according to claim 1, characterized in that The sensor further includes a diffusion control medium for controlling the diffusion rate of vapor entering the sensor.

5. The sensor according to claim 1, characterized in that The sensor further includes a filter device placed in the exhaust passage to prevent reactive gas from contacting the sensor via the exhaust passage.

6. The sensor according to claim 1, characterized in that The electrode includes two electrodes or includes three or more electrodes.

7. The sensor according to claim 6, characterized in that The electrolyte includes sulfuric acid or phosphoric acid.

8. The sensor according to claim 6, characterized in that The electrolyte is contained in an electrolyte accumulating wafer.

9. The sensor according to claim 1, characterized in that The sample inlet channel is a pore, a capillary or a membrane.

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