OPTICAL SENSOR DEVICE

Abstract

The invention relates to an optical sensor device for measuring at least two analytes. The sensor device contains at least one first dye and a second dye, wherein the dyes have an optical behaviour that depends on the respective analytes. The at least one first dye is contained in a membrane. The membrane limits a cavity. The cavity contains a buffer mixed with the second dye. A reservoir for the buffer and second dye is provided, the reservoir being in diffusive contact with the cavity. The optical behaviour of the dyes can be stimulated with excitation light, and the resulting optical behaviour can for example be detected by photodetectors making use of associated dichroic mirrors. Components of the optical sensor device may be arranged in a common housing.

Claims

1. A sensor device for measuring at least one first analyte and a second analyte, the sensor device comprising: a cavity; a buffer contained in the cavity; a membrane, limiting the cavity at least on one side of the cavity, wherein the membrane includes at least one first dye within the membrane, each of the at least one first dye exhibiting a first optical behaviour which depends on a respective first analyte; a second dye mixed with the buffer, the second dye exhibiting a second optical behaviour which depends on a pH-value in the buffer, wherein the pH-value in the buffer depends on the second analyte; and, a reservoir of the buffer and the second dye, wherein the reservoir is in diffusive contact with the cavity.

2. The sensor device according to claim 1, wherein the reservoir is of annular shape.

3. The sensor device according to claim 1, wherein the reservoir is at least partially surrounded by an opaque layer.

4. The sensor device according to claim 1, further comprising an optics section, the optics section including a dichroic mirror and an associated photodetector for each of the at least one first dye and also including a dichroic mirror and an associated photodetector for the second dye.

5. The sensor device according to claim 4, wherein the optics section further comprises a beam splitter and an associated photodetector for generating a reference signal for a light source.

6. The sensor device according to claim 4, wherein an optical waveguide is provided for guiding light from the optics section towards the at least one first dye and the second dye, and/or for guiding light emitted from or having interacted with at least one of the at least one first dye and/or light emitted from or having interacted with the second dye to the optics section.

7. The sensor device according to claim 4, further comprising a control and evaluation section for controlling the optics section and processing signals received from the photodetectors of the optics section.

8. The sensor device according to claim 7, wherein the control and evaluation section, the optics section, and the cavity are contained in a common housing, closed on one side by the membrane.

9. The sensor device according to claim 8, wherein the housing is provided with means for mechanically connecting the sensor device to a port provided in a vessel.

10. The sensor device according to claim 8, wherein the housing is provided with an interface for power supply of the sensor device and/or for data transfer between the sensor device and an external device.

11. The sensor device according to claim 7, wherein the optics section is detachable from the control and evaluation section.

12. The sensor device according to claim 7, wherein the control and evaluation section has a memory for storing calibration data for the sensor device.

13. The sensor device according to claim 4, wherein the cavity with the membrane is detachable from the optics section.

14. The sensor device according to claim 1, wherein the at least one first dye in the membrane is enclosed in hollow particles, or contained within pores in the membrane, or absorbed in carrier particles, or dissolved in carrier particles, or adsorbed to carrier particles, or forms particles within the membrane.

15. The sensor device according to claim 1, wherein a side of the membrane facing away from the cavity is opaque.

16. The sensor device according to claim 1, wherein the cavity contains a spacer element, wherein the membrane and the spacer element are selected in such a way that a diffusion coefficient for a diffusion of the second analyte through the membrane is higher by a factor of 10 to 100 than a diffusion coefficient of the buffer and the second dye in the cavity through the spacer element.

17. The sensor device according to claim 1, wherein the membrane includes a mesh sandwiched between two fluoropolymer films.

18. The sensor device according to claim 17, wherein the mesh between the fluoropolymer films is embedded in silicone.

19. A sensor device for measuring at least one first analyte and a second analyte, the sensor device comprising: a cavity; a buffer contained in the cavity; a membrane, limiting the cavity at least on one side of the cavity, wherein the membrane includes at least one first dye within the membrane, each of the at least one first dye exhibiting a first optical behaviour which depends on a respective first analyte; a second dye mixed with the buffer, the second dye exhibiting a second optical behaviour which depends on a pH-value in the buffer, wherein the pH-value in the buffer depends on the second analyte; a reservoir of the buffer and the second dye, wherein the reservoir is in diffusive contact with the cavity; an optics section, the optics section including a dichroic mirror and an associated photodetector for each of the at least one first dye and also including a dichroic mirror and an associated photodetector for the second dye; a control and evaluation section for controlling the optics section and processing signals received from the photodetectors of the optics section; and, a housing, closed on one side by the membrane, wherein the control and evaluation section, the optics section, and the cavity are contained in the housing.

20. A sensor device for measuring at least one first analyte and a second analyte, the sensor device comprising: a cavity; a buffer contained in the cavity; a membrane, limiting the cavity at least on one side of the cavity, wherein the membrane includes at least one first dye within the membrane, each of the at least one first dye exhibiting a first optical behaviour which depends on a respective first analyte; a second dye mixed with the buffer, the second dye exhibiting a second optical behaviour which depends on a pH-value in the buffer, wherein the pH-value in the buffer depends on the second analyte; a reservoir of the buffer and the second dye, wherein the reservoir is in diffusive contact with the cavity; an optics section, the optics section including a dichroic mirror and an associated photodetector for each of the at least one first dye and also including a dichroic mirror and an associated photodetector for the second dye; and, a control and evaluation section for controlling the optics section and processing signals received from the photodetectors of the optics section; wherein the cavity with the membrane is detachable from the optics section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:

[0045] FIG. 1 illustrates a schematic representation of a simple example of a sensor device;

[0046] FIG. 2 illustrates a schematic representation of an embodiment of the sensor device according to the invention including a reservoir for buffer and second dye;

[0047] FIG. 3 illustrates, schematically, an example embodiment of a sensor device according to the invention including a reservoir for buffer and second dye;

[0048] FIG. 4 illustrates how the sensor device, shown in FIG. 3, is assembled;

[0049] FIG. 5 illustrates a schematic top view of the sensor device according to FIG. 3;

[0050] FIG. 6 illustrates a schematic cross section of a membrane for a sensor device according to the invention;

[0051] FIG. 7 illustrates an assembly which can either be used as a variant of the sensor device shown in FIG. 1, or as part of a sensor device according to the invention as shown in FIG. 8;

[0052] FIG. 8 illustrates a sensor device according to the invention with an optics section and a control and evaluation section;

[0053] FIG. 9 illustrates an enlarged view of the tip of the sensor device shown in FIG. 8;

[0054] FIG. 10 illustrates a schematic representation of a sensor device according to the invention, the sensor device being of modular configuration;

[0055] FIG. 11 illustrates a sensor device according to the invention in a vessel and connected to an external device.

DETAILED DESCRIPTION

[0056] At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements. It is to be understood that the claims are not limited to the disclosed aspects.

[0057] Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the claims.

[0058] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments.

[0059] It should be appreciated that the term substantially is synonymous with terms such as nearly, very nearly, about, approximately, around, bordering on, close to, essentially, in the neighborhood of, in the vicinity of, etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term proximate is synonymous with terms such as nearby, close, adjacent, neighboring, immediate, adjoining, etc., and such terms may be used interchangeably as appearing in the specification and claims. The term approximately is intended to mean values within ten percent of the specified value.

[0060] Adverting now to the figures, FIG. 1 shows a schematic representation illustrating the basic setup of an example of sensor device 100. Membrane 1 limits cavity 2 at least on one side of cavity 2. Membrane 1 contains at least one first dye 11. First dye 11, as mentioned above, may be distributed homogeneously in the membrane or a layer thereof, or may be distributed inhomogeneously, in or at particles contained in membrane 1. Cavity 2 contains buffer 21 and second dye 22 mixed with buffer 21. Buffer 21 is a pH-buffer solution. Cavity 2 is also limited by transparent element 23, on a side of cavity 2 not limited by membrane 1. In the example shown, cavity 2 is formed in transparent element 23, which surrounds cavity 2 on all sides but one, and this remaining side is limited by membrane 1.

[0061] When measuring at least one first analyte and a second analyte in a medium, membrane 1 is brought into contact with the medium, the at least one first analyte and the second analyte enter membrane 1 by diffusion, and subsequently at least the second analyte passes from membrane 1 into cavity 2 by diffusion. The at least one first analyte affects an optical behaviour of a corresponding at least one first dye 11 in membrane 1, and the second analyte affects an optical behaviour of second dye 22 in cavity 2 via a change of the pH-value of buffer 21. The optical behaviour of the at least one first dye 11 and second dye 22 can be monitored by shining light through transparent element 23 on the at least one first dye 11 and second dye 22, which results in light emitted from, or having interacted with, at least one of the at least one first dye 11 or second dye 22, which can pass through transparent element 23 to be registered for evaluation by adequate means. Such means are not shown here. Although such means are not required to form part of a sensor device according to the invention, some example embodiments, for example the embodiment shown in FIG. 8, do include such means.

[0062] Sensor device 100 may for example be used to detect gases like sulphur dioxide (SO.sub.2), ammonia (NH.sub.3), oxygen (O.sub.2), or carbon dioxide (CO.sub.2). For the detection of oxygen, for example, platinum octaethylporphyrin may be used as a first dye, attached to polystyrene nanoparticles embedded in the membrane. An example of a second dye is hydroxypyrenetrisulfonic acid, and it may be employed in a bicarbonate buffer for the detection of carbon dioxide. Another example for a buffer may be a solution of sodium bisulfate. Additionally, when setting a desired osmolality in the buffer, sodium sulfate may be used. Neither this example nor the invention is limited to the dyes, buffers, and osmolality setting additives just mentioned. Further examples of suitable dyes, and, where applicable, adequate buffers to be used with the dyes, as well as of additives suitable for setting a desired osmolality in a respective buffer, are known in the art for measuring a wide range of analytes.

[0063] FIG. 2 schematically shows an example embodiment of sensor device 100 according to the invention. The example embodiment shown in FIG. 2 is largely identical to the example of a sensor device shown in FIG. 1. Therefore, most of the elements shown in FIG. 2 occur and have already been described with respect to FIG. 1. The example embodiment shown in FIG. 2, according to the invention, has reservoir 3 which contains a mixture of buffer 21 and second dye 22, similar to cavity 2. In the example embodiment shown in FIG. 2, reservoir 3 has the form of a ring surrounding the further elements of sensor device 100. The walls of cavity 2, formed by transparent element 23, exhibit diffusion portions 31, through which a diffusive contact between reservoir 3 and cavity 2 is established. Diffusion portions 31, without being limited thereto, may comprise a plurality of small holes formed in the walls of cavity 2, or one or plural channels in the walls of the cavity, the channels filled with a porous or fibrous matter, or with a mesh.

[0064] FIG. 3 illustrates another example embodiment of sensor device 100 according to the invention. Transparent element 23 here is a plastic disc, preferentially chemically inert, so as to avoid detrimental effects of the chemistry in sensor device 100 or in a medium where sensor device 100 is used for measurements on sensor device 100. Advantageously, the plastic disc is chosen such that its material does not deteriorate when exposed to light of wavelength and intensity ranges as used in measurements. Non-limiting examples of such materials are polysulphone, polyether sulphone, polystyrene, cyclic olefin copolymers (COCs).

[0065] Reservoir 3 here is formed as an annular recess in transparent element 23. Reservoir 3 is partially covered with opaque layer 32. Opaque layer 32 prevents the contents of reservoir 3, i.e. buffer and second dye (not indicated here), from undesired exposure to light, thus increasing the lifetime of sensor device 100 and preventing a strong hysteresis of the sensor signal, as has already been discussed above. Cavity 2 contains spacer element 24, which at the same time limits reservoir 3 in such a way that reservoir 3 remains in diffusive contact with cavity 2. Spacer element 24, in addition to examples mentioned elsewhere in the application, may for example be a woven or non-woven steel or nylon mesh or PETE-mesh, these examples being independent of the specific embodiment of sensor device 100. In the embodiment shown in FIG. 3, spacer element 24 also maintains a defined distance between membrane 1 and transparent element 23. Spacer element 24 is at least semi-transparent to light of wavelengths used in measurements with the sensor device, letting pass at least 40% of light intensity at any such wavelength, but may of course also be transparent in the sense defined above. Membrane 1 covers spacer element 24 and thus cavity 2, and is held in place by jagged fixing ring 12 pressed against membrane 1 by clamping ring 13.

[0066] FIG. 4 illustrates the assembly of sensor device 100 shown in FIG. 3. The elements of sensor device 100 have already been discussed in the context of FIG. 3. Spacer element 24, soaked with buffer and second dye, is placed on transparent element 23 and covered with membrane 1. Fixing ring 12 is brought into contact with membrane 1 as shown. By pushing clamping ring 13 over fixing ring 12 in direction of arrows 101, fixing ring 12 is pressed against membrane 1 and transparent element 23 as indicated by arrows 102. Clamping ring 13 and fixing ring 12 thus lock membrane 1 in place against transparent element 23, in this way also stabilizing and holding together sensor device 100, with cavity 2 being formed by the space between membrane 1 and transparent element 23 defined by spacer element 24.

[0067] FIG. 5 is a schematic top view of sensor device 100 as shown in FIG. 3. In this Figure, clamping ring 13, fixing ring 12, and membrane 1 are shown. Indicated by two dashed concentric circles is the position of reservoir 3 below membrane 1 and cavity 2 (see FIG. 3).

[0068] Reservoir 3 of annular shape assists in establishing chemically more homogeneous conditions in cavity 2 via diffusive exchange of buffer and second dye between cavity 2 and reservoir 3. However, the invention is not limited to reservoirs of annular shape. In embodiments like those shown in FIGS. 3 and 5, light passing through transparent element 23 towards cavity 2, as well as light propagating in the reverse direction, may be collimated by annular reservoir 3 covered with opaque layer 32.

[0069] FIG. 6 illustrates a schematic cross section of an example embodiment of membrane 1 for use in a sensor device according to the invention. Membrane 1 has a multilayer structure, including films 14 and 15, which for example are made of polytetrafluoroethylene (PTFE). When measuring, film 14 is arranged towards the medium containing the analytes to be measured. Film 15 is arranged towards cavity 2 (see FIG. 3, for example). Between films 14 and 15, mesh 16 is provided, which, for example, is made of steel or plastic. Mesh 16 is embedded in silicone; part of the silicone is transparent silicone 19, containing particles 18 with the at least one first dye. Another part of the silicone is black silicone 17, for example Wacker N189; black silicone may for example also be obtained by mixing silicone with soot, graphite, or Fe.sub.3O.sub.4. Black silicone 17 is adjacent to film 14, and transparent silicone 19 is adjacent to film 15. Therefore, the side of membrane 1 where film 14 is located is opaque. On the other hand, light can propagate into and through transparent silicone 19 with particles 18. The at least one first analyte and the second analyte can diffuse through film 14, black silicone 17, and transparent silicone 19. At least the second analyte can also diffuse through film 15, to enter cavity 2. In this way the analytes can reach the respective dyes provided for measuring them. Light used in measuring, both excitation light and light emitted from or having interacted with at least one dye, cannot pass black silicone 17 and therefore cannot enter the medium containing the analytes to be measured. The advantages of having the side of membrane 1 towards the medium opaque due to the black silicone 17, but not limited thereto, have already been discussed above. Instead of having the at least one first dye located at particles 18 dispersed in transparent silicone 19, the at least one first dye could also be distributed homogeneously within transparent silicone 19. The sides of films 14 and 15 facing the silicone may be plasma etched to improve adhesion to the silicone.

[0070] FIG. 7 illustrates an assembly that can form part of sensor device 100 as shown in FIG. 8, but can also be used as a variant of sensor device 100 shown in FIG. 1. The assembly contains membrane 1 of multilayer structure, as just described in the context of FIG. 6. For better establishing this context, films 14 and 15, as well as mesh 16 are indicated. Cavity 2 is formed between membrane 1 and transparent element 23. Cavity 2 here contains spacer element 24, already described above. Transparent element 23 here is shaped as a lens. Opaque element 25 is provided to further limit the assembly on sides where neither membrane 1 nor transparent element 23 provide such a limiting function. Opaque element 25 may for example be made of stainless steel or of a plastic like polyether ether ketone (PEEK). Opaque element 25 may also be a portion of a larger component, if the assembly shown here is integrated into a larger device like sensor device 100 shown in FIG. 8. In case cavity 2 of the assembly shown is in diffusive contact with a reservoir (not shown here), gaps may be provided between opaque element 25 and transparent element 23, so that buffer-dye mixture from the reservoir can enter cavity 2.

[0071] In another example embodiment, films 14 and 15 each have a thickness of 5 m, mesh 16 is a steel mesh of 80 m layer thickness with a 60 m mesh size, spacer element 24 also is a steel mesh of 80 m layer thickness with a 60 m mesh size. These dimensions are in no way limiting to the invention.

[0072] FIG. 8 illustrates an example embodiment of sensor device 100 according to the invention, having optics section 50 and control and evaluation section 70 within housing 80. Also shown is an assembly like that illustrated in FIG. 7, of which, membrane 1 and transparent element 23 are indicated. Furthermore, waveguide 33 is provided, which establishes an optical connection between transparent element 23 and optics section 50. Thus, waveguide 33 in particular can guide light from the optics section towards the at least one first dye and the second dye, via transparent element 23, and can also guide light in the reverse direction. In the embodiment shown, waveguide 33 passes through reservoir 3. Waveguide 33 may for example be a glass rod. As has been discussed before, reservoir 3 is in diffusive contact with cavity 2 (see FIG. 7).

[0073] Optics section 50 has one dichroic mirror 51 for each first dye 11 contained in membrane 1. Dichroic mirror 51 here is associated with photodetector 53. Only one dichroic mirror 51 with associated photodetector 53 is shown. Additionally, brackets 110 with subscript n are provided, which indicate that this combination of elements may be present in sensor device 100 repeatedly, once for each first dye 11 in membrane 1. Dichroic mirror 51 exhibits a wavelength-dependent reflectivity which is chosen such that dichroic mirror 51 reflects light from the corresponding first dye 11 in membrane 1 to the associated photodetector 53. Photodetector 53 outputs an electric signal indicative of the light intensity received by it. Thus the optical behaviour of first dye 11 can be monitored.

[0074] Optics section 50 furthermore has dichroic mirror 52 corresponding to second dye 22 contained in cavity 2. Dichroic mirror 52 here is associated with photodetector 54. Dichroic mirror 52 exhibits a wavelength-dependent reflectivity which is chosen such that dichroic mirror 52 reflects light from the corresponding second dye 22 in cavity 2 to the associated photodetector 54. Photodetector 54 outputs an electric signal indicative of the light intensity received by it. Thus the optical behaviour of second dye 22 can be monitored.

[0075] In the example embodiment shown in FIG. 8, optics section 50 includes beam splitter 55 with associated photodetector 56. Beam splitter 55 is provided to divert a portion of excitation light from a light source to the associated photodetector 56, in order to monitor the intensity of the excitation light. For several methods of measuring analytes via optical sensors, the intensity of the excitation light must be known for evaluation of the signals received from the dyes in the sensors. Usually, beam splitter 55 is configured to direct between 0.5% and 6% of the intensity of the excitation light impinging on beam splitter 55 to the associated photodetector 56, while letting the remaining light pass on towards the at least one first dye 11 and second dye 22. These percentage values, however, do not constitute a limitation of the invention. The light source can be a light source external to the sensor device, with the excitation light coupled into the sensor device by suitable means. In the example embodiment shown, light source 60 is integrated into sensor device 100. As an example of such a light source, i.e., light source 60, the drawings illustrate a plurality of, more specifically two, light emitting diodes (LEDs) 61, which, for example, may be configured as surface-mounted devices, in this way contributing to a compact design of sensor device 100.

[0076] Control and evaluation section 70, in the embodiment shown in FIG. 8, contains printed circuit board 71 with electronic components constituting one or plural circuits for controlling sensor device 100 and processing signals received from photodetectors 53, 54, and 56. Printed circuit board 71 may in particular include integrated circuits or chips. At least one of these integrated circuits or chips may function as a memory device, for storing data relevant to the processing of signals received from photodetectors 53, 54, and 56; in particular, the memory device on printed circuit board 71 may store calibration data for sensor device 100. One way to establish an electric connection between photodetectors 53, 54, and 56 and printed circuit board 71 is to mount photodetectors 53, 54, and 56 on printed circuit board 57 in optics section 50, and to connect this printed circuit board 57 to printed circuit board 71 in control and evaluation section 70 via suitable wiring 72. Via further wiring 74, printed circuit board 71 is connected to plug 81. Plug 81, in the embodiment shown, serves as an interface for connecting sensor device 100 to external device 90 (see FIG. 11). Plug 81 in particular may provide connections both for power supply of sensor device 100 and for communication between sensor device 100 and external device 90. Via screw element 82, sensor device 100 can be mechanically connected to port 203 provided in vessel 200 (see FIG. 11), fixing sensor device 100 in place in vessel 200. Plug 81 is only an example of an interface, other types of interface, different from a plug, may also be used. Screw element 82 is only provided as an example of a means for mechanically connecting the sensor device 100 to port 203 in vessel 200, and different types of means therefor may be used.

[0077] Optics section 50 may contain further optical elements. As non-limiting examples thereof, lenses 62 and 63 are shown. For example, lens 62 may be used to collect light emitted by LEDs 61 and shape it into a beam directed towards lens 63, which focuses the light into waveguide 33. Housing 80 may contain further elements. For example, a thermistor (e.g. NTC, Pt100, Pt1000) may be provided in housing 80 for measuring the temperature and thus determine a parameter of the ambient conditions sensor device 100 is used in. Knowledge of the ambient conditions may contribute to the accuracy of the measurement results obtained with sensor device 100, as, for example, the ambient conditions, in particular temperature, can affect a calibration of sensor device 100. In other example embodiments, photodetectors 53 and 54, associated with dichroic mirrors 51 and 52, respectively, may in addition be covered with filters 58, to more precisely define the wavelength range of light reaching respective photodetectors 53 and 54. For more precisely defining the wavelength range of excitation light, one or more filters 64 with a respective suitable transmission may be provided for light source 60, for example one filter for each LED 61, where LEDs 61 can be controlled independently of each other, so that excitation light of different wavelength ranges may be used, depending on requirements of the measuring task.

[0078] Sensor device 100, including in particular plug 81, may be sterilisable, for example in an autoclave. Plug 81, without being limited thereto, may be an Interconnex VP6 or VP8.

[0079] FIG. 9 illustrates the portion of sensor device 100 shown in FIG. 8 containing cavity 2 and membrane 1 in an enlarged view. Cavity 2, as also shown in FIG. 7, is formed between membrane 1 and transparent element 23. Spacer element 24 in cavity 2 defines cavity 2, as has been explained above, and establishes a diffusive contact between cavity 2 and reservoir 3, for countering the effects of sensor poisoning. Reservoir 3 is arranged around waveguide 33. Opaque layer 32 is provided between waveguide 33 and reservoir 3.

[0080] FIG. 10 illustrates a schematic representation of sensor device 100 according to the invention. Sensor device 100 has optics section 50 and control and evaluation section 70 in addition to a portion including membrane 1, cavity 2, reservoir 3, and transparent element 23. Details of these elements have already been discussed above; reservoir 3 is in diffusive contact with cavity 2, and membrane 1 may for example be of the type shown in FIG. 6. In optics section 50, only light source 60, dichroic mirrors 51, 52, and respectively associated photodetectors 53 and 54 are shown. Optics section 50 may of course include further elements, for example as discussed in the context of FIG. 8. Control and evaluation section 70 contains data processing unit 75, and memory 76 connected to data processing unit 75. Memory 76 at least holds calibration data 77 for sensor device 100.

[0081] Control and evaluation section 70, optics section 50, and the portion including membrane 1, cavity 2, reservoir 3, and transparent element 23 here are shown separate from each other, in order to emphasize the modular configuration of the embodiment of sensor device 100 according to the invention shown here. For conducting a measurement, control and evaluation section 70, optics section 50, and a portion including membrane 1, cavity 2, reservoir 3, and transparent element 23 may be selected, according to their respective suitability for the specific measurement to be performed. In the resulting sensor device 100, the portion including membrane 1, cavity 2, reservoir 3, and transparent element 23 is in optical contact with optics section 50, and photodetectors 53 and 54 are in electrical contact with control and evaluation section 70, for example as shown in FIG. 8. Data processing unit 75 and memory 76 may for example be implemented as integrated circuits on a printed circuit board, like the one shown in the control and evaluation section in FIG. 8. While the implementation by printed circuit boards and integrated circuits is currently preferred, the invention is not limited thereto. Also shown is interface 81 for communication between sensor device 100 and external device 90 (see FIG. 11). Calibration data 77 may be transferred to memory 76 via interface 81.

[0082] FIG. 11 illustrates vessel 200, which may for example be a bio-reactor, but which is not limited thereto. Vessel 200 contains medium 202, in which at least one first analyte and a second analyte are to be measured with sensor device 100 according to the invention. For sensor device 100, membrane 1 is indicated. Sensor device 100 is mechanically connected to port 203 provided in wall 201 of vessel 200 by means 82, like for example a screw element as shown in FIG. 8. In the example embodiment shown in FIG. 11, interface 81 of sensor device 100, via cable 95, is connected to interface 94 of external device 90. In the example shown, external device 90 includes data processing unit 91, memory 92, and user interface 93. Memory 92 may hold calibration data 77 for sensor device 100, at least temporarily.

[0083] External device 90 can, for example, receive signals processed by control and evaluation section 70 (see FIGS. 8 and 10) through interface 94 and operate data processing unit 91 to derive values for the concentration, or partial pressure, of the at least one first analyte and of the second analyte from the signals received. Calibration data 77 for sensor device 100 stored in memory 92 may be used therein. Calibration data 77, or a portion thereof, may also be communicated to sensor device 100 via interface 94, cable 95, and interface 81; and control and evaluation section 70 of sensor device 100 may then use the calibration data for processing signals received from photodetectors of sensor device 100, like for example photodetectors 53, 54, and 56 shown in FIG. 8. The derived values for the concentration, or partial pressure, of the at least one first analyte and of the second analyte may then be output to a user via user interface 93, and/or stored in memory 92 or transferred to a further external device for later use.

[0084] Apart from providing a communication or data link between external device 90 and sensor device 100, interface 94, cable 95, and interface 81 may also be used for power supply of sensor device 100. Alternatively, of course, power may be supplied to sensor device 100 in a different way, for example by a separate power line. Wireless communication between sensor device 100 and external device 90 may also be used in example embodiments. User interface 93 can have further purposes, like for example starting, and setting parameters for, one or plural measurements to be conducted with sensor device 100. To the extent necessary, such parameters may also be communicated to sensor device 100, in the example embodiment shown in FIG. 11 via interface 94, cable 95, and interface 81.

[0085] It will be appreciated that various aspects of the disclosure above and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.