Sensor Element and Use of Same

Abstract

A sensor element has a channel into which a sensor substance can be fed from a reservoir of the sensor element. The sensor substance has an optical behaviour which depends on an analyte. The analyte passes from a sample through a membrane permeable to the analyte into the channel, which membrane forms a portion of a wall of the channel.

Claims

1. A sensor element comprising: a reservoir comprising a sensor substance having an optical behaviour depending on an analyte; a channel, wherein the sensor element is configured such that the sensor substance can be fed from the reservoir into the channel; and a membrane which is permeable to the analyte and which forms a portion of a wall of the channel.

2. The sensor element according to claim 1, wherein the channel is formed in a carrier plate and covered by the membrane.

3. The sensor element according to claim 1, wherein the channel is formed by an inner region of a tube formed by the membrane.

4. The sensor element according to claim 3, wherein the tube is arranged on a carrier plate.

5. The sensor element according to claim 1, wherein the reservoir is formed by a blister.

6. The sensor element according to claim 1, wherein the reservoir is separated from the channel by a barrier, wherein the barrier has a weakened portion, or wherein the sensor element comprises a device by which the barrier can be perforated.

7. The sensor element according to claim 1, wherein the sensor element has a plurality of reservoirs, and the sensor element is configured such that a content of each reservoir of the plurality of reservoirs can be fed into the channel.

8. The sensor element according to claim 7, wherein one reservoir of the plurality of reservoirs comprises a flushing liquid.

9. The sensor element according to claim 1, wherein the sensor element comprises a receptacle chamber into which the channel opens.

10. The sensor element according to claim 9, wherein the receptacle chamber is formed by a blister.

11. The sensor element according to claim 1, further comprising a first shutter device and a second shutter device, wherein a section of the channel extending between the first shutter device and the second shutter device can be shut off by the first shutter device and the second shutter device.

12. The sensor element according to claim 1, wherein the sensor element comprises a plurality of channels.

13. The sensor element according to claim 12, further comprising a reservoir in which a reference substance is contained, wherein the sensor element is configured such that the reference substance can be fed into another channel of the plurality of channels.

14. The sensor element according to claim 12, wherein a first sensor substance from a first reservoir can be fed into a first channel of the plurality of channels, a second sensor substance from a second reservoir can be fed into a second channel of the plurality of channels, and wherein the first sensor substance and the second sensor substance differ with respect to the analyte on which a respective optical behaviour of the respective sensor substance depends, and/or with respect to a range of values of the analyte for which a dependence of the respective optical behaviour of the respective sensor substance on the analyte manifests itself, and/or with respect to a type of the optical behaviour.

15. The sensor element according to claim 1, wherein at least two sensor substances are provided to be fed into a channel of the sensor element and wherein the sensor substances differ with respect to the analyte on which a respective optical behaviour of the respective sensor substance depends, and/or with respect to a range of values of the analyte for which a dependence of the respective optical behaviour of the respective sensor substance manifests itself, and/or with respect to a type of optical behaviour.

16. The sensor element according to claim 1, wherein a reservoir comprises a plurality of chambers and at least one component of a sensor composition is stored in each of the chambers.

17. A method of using a sensor element for detecting an analyte in a sample, the method comprising: providing a sensor element comprising: a reservoir containing a sensor substance having an optical behaviour depending on an analyte; a channel, wherein the sensor element is configured such that the sensor substance can be fed from the reservoir into the channel; and a membrane which is permeable to the analyte and which forms a portion of a wall of the channel; bringing the membrane into contact with the sample; feeding the sensor composition into the channel; directing light onto the channel; and recording optical signals from the channel and evaluating recorded optical signals for qualitative or quantitative detection of the analyte.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Below, the invention and its advantages are explained in more detail with reference to the attached drawings.

[0033] FIG. 1 shows a top view of a sensor element according to the invention.

[0034] FIG. 2 shows a sectional view of the sensor element according to the invention from FIG. 1.

[0035] FIG. 3 shows a top view of a further sensor element according to the invention.

[0036] FIG. 4 shows a top view of a further sensor element according to the invention.

[0037] FIG. 5 shows a sectional view of a sensor element according to the invention.

[0038] FIG. 6 shows a sectional view of a reservoir.

[0039] FIG. 7 shows a sensor element according to the invention in a measuring arrangement.

[0040] FIG. 8 shows a sensor element according to the invention in a further measuring arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The figures only show examples of the invention in a schematic manner, without limiting the invention to the examples shown. It should also be noted that, for reasons of clarity of presentation to illustrate the invention, the elements shown in the drawings are not necessarily to scale.

[0042] FIG. 1 shows a top view of a sensor element 1 according to the invention, wherein membrane 3 (see FIG. 2) is not shown. In the embodiment shown, the channel 2 runs in meanders and is formed in a carrier plate 5. A sensor substance can be fed into channel 2 from a reservoir 4. This is done in preparation for a measurement. Previously, as long as the sensor element 1 for instance is stored and only kept available for use, the sensor substance is enclosed in the reservoir 4, sometimes as a component of a sensor composition. The embodiment of the sensor element 1 shown further has a receptacle chamber 6.

[0043] Compared with a channel running straight between reservoir 4 and receptacle chamber 6, the meandering channel 2 used in the embodiment shown has the advantage that a larger amount of sensor composition and thus a larger amount of sensor substance can be provided in channel 2. Thus, excitation light can be used more efficiently and e.g. a more intense luminescence signal of the sensor substance can be received from channel 2. Thus, a given relative change in luminescence intensity is also greater in absolute terms, which improves the accuracy of the measurement. Nevertheless, the invention can also be realized with a linear channel.

[0044] FIG. 2 shows a sectional view of the sensor element 1 of FIG. 1 according to the invention along line 100 shown in FIG. 1. The shape of channel 2 is shown in simplified form. The carrier plate 5 is covered by membrane 3. The membrane 3 also covers channel 2 and thus forms a portion of a wall of channel 2.

[0045] Barrier 41 is also shown, through which reservoir 4 is sealed against channel 2. In the state shown, there is thus no sensor substance in channel 2. The reservoir 4 may, for example, be formed by a blister. If a sufficiently large force is exerted on the reservoir or blister 4, respectively, in the direction of the arrow 101, a weakened portion 43 of barrier 41 opens and the contents of the reservoir can enter channel 2. In embodiments, channel 2 has a rectangular cross section of e.g. 100 m by 100 m size, without, however, limiting the invention to this. With such dimensions, the filling of channel 2 with sensor composition from reservoir 4 is facilitated by capillary forces. If channel 2 and a surface 31 of membrane 3 facing channel 2 are hydrophilized, the filling of channel 2 is additionally facilitated. The force on the reservoir 4 in the direction of the arrow 101 may be applied directly by a user, for example by pressing with a finger, or, for example, by a plunger or other element of a higher-level apparatus into which the sensor element 1 is inserted. This is irrelevant to the principle of the invention. Likewise, the exact design of the barrier, of the weakened portion 43 or of a perforation mechanism for the barrier are not relevant to the invention; corresponding details can be taken from the prior art if necessary.

[0046] FIG. 3 shows, corresponding to the illustration in FIG. 1, a further version of a sensor element 1 according to the invention. In sensor element 1, channel 2 is formed in a carrier plate 5. The channel 2 opens into a receptacle chamber 6. In the embodiment shown the sensor element 1 has a plurality of reservoirs 4, here in particular three reservoirs 4. For example, each of the reservoirs 4 may contain the same sensor composition, channel 2 is then filled with sensor composition from one of the reservoirs 4, and sensor element 1 is used for measurements. If necessary, the sensor composition in channel 2 can then be renewed from one of the other reservoirs 4. Also, one of the reservoirs 4 may contain flushing liquid for channel 2. In order to avoid a flow of sensor composition or flushing liquid from a reservoir 4 into a previously emptied reservoir 4, valves may be provided, e.g. in junction area 24. A first shutter device 21 and a second shutter device 22 are provided for channel 2 in the embodiment shown. A section 23 of channel 2 between the first shutter device 21 and the second shutter device 22 can be shut off by the shutter devices 21, 22. This may be done, for example, after filling channel 2 with sensor composition in order to avoid a flow of the sensor composition through channel 2 and especially through the meandering section 23 during a measurement; such a flow may be caused, for example, by a temperature gradient along the channel and cause a drift of an optical signal from channel 2.

[0047] FIG. 4 shows, corresponding to the illustration in FIG. 1, a further embodiment of a sensor element 1 according to the invention. The sensor element 1 has, in carrier plate 5, a first channel 25 and a second channel 26, each of which opens into a separate receptacle chamber 6. It is also conceivable that both channels 25 and 26 open into a common receptacle chamber. In one configuration, a first sensor substance can be fed into the first channel 25 from a first reservoir 45, for example as a component of a sensor composition. In this configuration, a second sensor substance, for example as a component of a sensor composition, can be fed into the second channel 26 from a second reservoir 46. The first and the second sensor substance may differ, for example, with respect to the analyte on which their respective optical behaviour depends. For example, the first sensor substance in the first channel 25 may emit luminescence light after excitation, the decay time of this luminescence depending on the partial pressure of oxygen; the second sensor substance in the second channel 26 may emit luminescence light after excitation, the decay time of this luminescence depending on the partial pressure of carbon dioxide. It is also possible that for both sensor substances the respective optical behaviour depends on the same analyte, for example on oxygen, but that the ranges of values of the concentration of the analyte differ in which a dependence of the optical behaviour of the respective sensor substance on the analyte is shown which is sufficient for a measurement. It is also possible that first and second sensor substances differ in the nature of their respective optical behaviour, for example, the colour of the first sensor substance may change in dependence on the concentration of an analyte, and the second sensor substance may exhibit a luminescence phenomenon, the decay time of which depends on the concentration of this analyte or of a different analyte.

[0048] In this way, two different analytes can be measured in one sample with the shown sensor element 1, or a larger range of the concentration or partial pressure of an analyte can be covered with sensor element 1.

[0049] In a different embodiment of the sensor element 1 shown, for example, a sensor substance can be fed into the first channel 25 from the first reservoir 45, for example as a component of a sensor composition. A reference substance, for example as a component of a reference composition, can be fed into the second channel 26 from the second reservoir 46. In this way, measurements of an analyte can be carried out with sensor element 1 using an optical behaviour of the sensor substance, wherein, for example, an optical behaviour of the reference substance is used for calibration purposes.

[0050] Also in the case of a sensor element 1 with several channels, for example as in FIG. 4 with two channels, several reservoirs can be provided for one or more of the channels, as shown in FIG. 3 for a channel 2.

[0051] FIG. 5 shows a cross section of another embodiment of a sensor element 1 according to the invention. In this embodiment the channel 2 is a tube 7, which is formed by the membrane 3. This means that a tube 7 or a hose is formed from the membrane 3, the interior of which tube or hose is the channel 2. The membrane 3 forms the wall of the tube 7 and thus of the channel 2. In the embodiment shown, the tube 7 is attached to a carrier plate 5, e.g. glued to the carrier plate 5, where it runs in meanders so that the tube 7 is captured several times by the section shown.

[0052] FIG. 6 shows a cross-section of an embodiment of a reservoir 4. The reservoir 4 shown has three chambers 42, in which components of a sensor composition can be stored separated from each other. Reservoir 4 is closed by a barrier 41. Barrier 41 has a weakened portion 43 for each chamber 42. When used in a sensor element 1, as shown and explained in FIG. 2 for the reservoir 4 shown there, the weakened portions 43 can be made to burst by exerting a force on the reservoir 4 so that the contents of the three chambers 42 enter the channel 2 and are mixed.

[0053] FIG. 7 shows a possible measuring arrangement 300, together with which the sensor element 1 according to the invention can be used to detect at least one analyte qualitatively or quantitatively in a sample 200. The sample 200 here is contained in a sample container 210; the sample container 210 may, for example, be a bioreactor, without limiting the invention to this. The sensor element 1 is mounted in a corresponding holder 220, for example a port of a bioreactor. Of sensor element 1, only membrane 3 and carrier plate 5 are shown. The membrane 3 is in contact with the sample 200, so that the at least one analyte can pass from the sample 200 through the membrane 3 to the channel or, depending on the configuration of sensor element 1, the channels of sensor element 1.

[0054] The measuring arrangement 300 here comprises a control unit 310, light sources 320 and a camera 330. The light sources 320 are intended to excite a luminescence of a sensor substance in a channel of sensor element 1, the camera 330 is intended to detect the luminescence signal from the sensor substance. Light sources 320 and camera 330 are controlled by the control unit 310. The evaluation, i.e. the determination of e.g. the concentration of the analyte, may also be carried out by the control unit 310.

[0055] In the embodiment shown, the carrier plate 5 is transparent to light from the light sources 320 for exciting the luminescence, and to the luminescence light. The membrane 3 can be configured such that it scatters light back to make better use of the excitation light and to direct a larger portion of the luminescence light towards the camera; to this end the membrane 3 may for example contain titanium dioxide particles. Additional optical elements, including filters, may be provided between light sources 320 and carrier plate 5 and/or between carrier plate 5 and camera 330. The sample container 210 may contain further elements, such as an agitator. Instead of the camera 330, other detector devices may be used. Instead of the free-beam optics shown here, excitation light and/or luminescence light may also be guided via waveguides, in particular optical fibres.

[0056] FIG. 8 shows a further possible measuring arrangement 300, with which the sensor element 1 according to the invention can be used to detect at least one analyte in a sample 200 qualitatively or quantitatively. The sample 200 is in a sample container 210, which is designed as a flow element, and here the sample 200 flows through the flow element in the flow direction 240. Sensor element 1, of which only membrane 3 and carrier plate 5 are shown, is located in a holder 220, which is provided in the wall of the flow element. The membrane 3 therein is in contact with the sample 200, so that the at least one analyte from the sample 200 can pass through the membrane 3 to the channel or, depending on the configuration of the sensor element 1, the channels of the sensor element 1. The measuring arrangement 300 here comprises a control unit 310 and an optical fibre 350, shown only very schematically. Suitable coupling devices for optical fibres to sensor elements are known to the person skilled in the art. The optical fibre 350 serves to guide light from a light source (not shown) provided in the control unit 310 to the sensor element 1 in order to there excite a luminescence of a sensor substance in a channel of the sensor element 1. Likewise, luminescence light generated in this way is guided from the sensor substance through the optical fibre 350 to the control unit 310 in order to there be, after detection by a detector (not shown) provided in the control unit 310, evaluated for the detection of the analyte. Instead of the optical fibre 350, free-beam optics, for example as shown in FIG. 7, could also be used here. Here too, as in the embodiment of FIG. 7, the membrane 3 may be configured to scatter back light. As in the embodiment of FIG. 7, the carrier plate 5 is transparent to light for exciting the luminescence of the sensor substance and to luminescence light from the sensor substance.

LIST OF REFERENCE SIGNS

[0057] 1 sensor element [0058] 2 channel [0059] 3 membrane [0060] 4 reservoir [0061] 5 carrier plate [0062] 6 receptacle chamber [0063] 7 tube [0064] 21 first shutter device [0065] 22 second shutter device [0066] 23 section of the channel [0067] 24 junction area [0068] 25 first channel [0069] 26 second channel [0070] 31 surface of the membrane [0071] 41 barrier [0072] 42 chamber [0073] 43 weakened portion [0074] 45 first reservoir [0075] 46 second reservoir [0076] 100 line [0077] 101 arrow [0078] 200 sample [0079] 210 sample container [0080] 220 holder for sensor element [0081] 240 flow direction [0082] 300 measuring arrangement [0083] 310 control unit [0084] 320 light source [0085] 330 camera [0086] 350 optical fibre