DE102014107837B4 - Optical sensor for the quantitative detection of an analyte in a sample and method for manufacturing the sensor - Google Patents

Abstract

Sensor (1) for the quantitative detection of an analyte in a sample (7), the sensor (1) at least one dye (2) having an optical behavior that can be influenced by the analyte within the sensor (1) and a medium (3) containing the dye (2), characterized by at least one hollow fiber section (4), inside of which the medium (3) with the dye (2) is located, and by an osmolality in the medium (3) which is greater is a predetermined maximum sample osmolality for which the sensor (1) is intended.

Description

The invention relates to a sensor for the quantitative detection of an analyte in a sample, in which an optical behavior of at least one dye is used for the quantitative detection of the analyte. The invention also relates to a method for producing such a sensor.

The translation DE 694 30 003 T2 of the European patent specification EP 0 731 664 B1 for international registration PCT / US94 / 12146 discloses a sensor with an indicator dye contained in an aqueous phase. The dye can be in a liquid that is adsorbed on particles or absorbed in particles; the particles, in turn, are embedded in a gas- and light-permeable polymeric material which does not allow liquid water to pass through. The aqueous phase can also be enclosed in micro-chambers. Furthermore, the aqueous phase can contain a buffer and salts for setting a desired osmolarity.

The international publication WO 00/26655 A1 the international application PCT / US99 / 25506 discloses a dye trapped in a recess of a sensor membrane. A perforated metal disc is placed under the sensor membrane to prevent the dye layer from swelling.

The German translation DE 692 19 061 T2 of the European patent specification EP 0 539 175 B1 describes, inter alia, the impregnation of a carrier with a reagent composition. This contains a buffer and can contain, for example, cellulose, gum arabic or polyvinylpyrrolidone as a binding agent.

The German translation DE 696 12 017 T2 of the European patent specification EP 0 873 517 B1 for international registration PCT / US96 / 16469 describes an aqueous phase with indicator and buffer, which is in a second hydrophobic phase. This emulsion can contain humectants. The aqueous phase is in microcompartments. Substances can be added which regulate the osmotic pressure.

The German Offenlegungsschrift DE 2 134 910 A1 relates to a dye for staining white blood cells and a method for the analytical determination of white blood cells in the blood. A blood sample is added to an aqueous solution containing a dye. The aqueous solution contains additives in order to keep a pH value and an osmolality within the normal ranges for human blood plasma.

The international publication WO 2009/140559 A1 for international registration PCT / US2009 / 044048 discloses a sensor element with a layer structure. An indicator is bound to a porous support membrane which is arranged on a polymer substrate. The support membrane can also consist of plastic fabric.

The US publication US 2004/171094 A1 relates to a dye with analyte-dependent phosphorescence which is enclosed in hydrophobic polymer particles. The particles for their part can be embedded in a layer or matrix which can absorb water and swell when water is absorbed.

The US publication US 2008/215254 A1 describes sensors which consist of one or more layers arranged on a transparent carrier. The layers can consist of a polymer and can be arranged, for example, in the cavities of a microtiter plate or at the end of a light guide.

The German patent specification that was subsequently published without prior disclosure DE 10 2013 108 659 B3 discloses a sensor for the quantitative detection of an analyte in a sample, in which an analyte-dependent optical behavior of at least one dye is used for the quantitative detection. The at least one dye is contained in a medium. A restriction means is provided to mechanically limit changes in volume of the medium. Furthermore, an osmolality in the medium is set so that it is greater than the largest sample osmolality for which the sensor is to be used. The interaction of the restriction agent with the predetermined high osmolality results in a greatly reduced osmolality cross-sensitivity of the sensor. The restriction agent can be embedded in the medium as a membrane, fleece, mesh, woven fabric or grid. Alternatively, it can also consist of a carrier plate with a large number of depressions in which the medium is arranged.

The patent specification US 6,428,748 B1 discloses a sensor in which a sensor mixture is introduced into a carrier layer. There is an indicator dye and a buffer in the sensor mix. In order to prevent water from flowing out of the sensor, a substance to increase the osmolarity is added to the sensor mixture. The value of the osmolarity achieved in this way in the sensor mixture can exceed the value of the osmolarity of a sample.

Optical sensors for the detection of acidic or basic gases, for example ammonia or sulfur dioxide, in gaseous samples or in Liquids dissolved are well known. These sensors have a dye with an optical behavior that is influenced by the gas to be detected, often indirectly, for example via a change in the pH value of a buffer solution containing the dye. As a rule, the buffer solution with the dye is separated from the sample to be examined by a gas-permeable material, for example a gas-permeable polymer. If water from the sample gets into the buffer solution because the gas-permeable material itself is water-absorbent and water then gets from the gas-permeable material into the buffer solution, or because water in the form of vapor diffuses through the gas-permeable material into the buffer solution, the concentration changes of the buffer and thus the pH value. This results in conditions in the sensor which no longer correspond to the calibration of the sensor. Since the water transport into the buffer solution is determined by the osmolalities of the buffer solution and the sample, the sensor is cross-sensitive to osmolality. This is particularly problematic if the osmolality of the sample changes over the duration of a measurement. This problem occurs, for example, in the field of biotechnology, where sensors of the type described are used to monitor bioprocesses, such as fermentations or cell cultivation. Also in the medical field, with online or offline measurements in blood, urine or tissue, strong changes in the osmolality can occur, which lead to large measurement errors in the sensors described according to the prior art.

The object of the invention is to provide a sensor which has a reduced cross-sensitivity to osmolality compared to the prior art, and the calibration of which is therefore largely independent of the osmolality of the sample.

This object is achieved by a sensor according to claim 1.

A further object of the invention is to provide a method with which a sensor can be produced which has a reduced cross-sensitivity to osmolality compared to the prior art, and the calibration of which is thus largely independent of the osmolality of the sample.

This object is achieved by a method according to claim 16.

The sensor according to the invention for the quantitative detection of an analyte in a sample comprises at least one dye which has an optical behavior which can be influenced by the analyte within the sensor, which is therefore directly or indirectly dependent on the analyte due to the design of the sensor. This means that conclusions can be drawn quantitatively about the analyte from the optical behavior of the at least one dye, for example a concentration or a partial pressure for the analyte can be determined. A calibration of the sensor is advantageously used for this purpose. Quantitative detection of the analyte is understood to mean that a value for the concentration or the partial pressure of the analyte is determined up to the error limits customary in the art, but also that it is only established that the concentration or the partial pressure of the analyte are within a predetermined range; the specified range can have a lower limit and an upper limit, or only either a lower limit or an upper limit.

Furthermore, the sensor according to the invention comprises a medium in which the at least one dye is contained; the medium can for example comprise a liquid in which the at least one dye is dissolved; Depending on the embodiment, the medium can contain further components, as will be explained below.

According to the invention, the sensor comprises at least one hollow fiber section, inside of which the medium with the dye is located, and also according to the invention there is an osmolality in the medium which is greater than a predetermined maximum sample osmolality for which the sensor is intended to be used. The sensor according to the invention should not be used for samples with an osmolality greater than this maximum sample osmolality, since the measurement results would not be reliable in such a case. In a preferred embodiment, the sensor comprises a plurality of hollow fiber sections, inside of which the medium is located.

The at least one hollow fiber section causes a mechanical restriction of a change in volume of the medium. The combination of this mechanical restriction with the given osmolality in the medium results in a defined absorption of solvent, for example water, into the medium when the sensor is brought into contact with a sample in which the analyte, i.e. the substance to be detected, is in the Solvent is dissolved. For gaseous samples, water can accordingly enter the sensor in the form of water vapor contained in the sample, and a defined absorption of water results analogously. As long as the osmolality in the medium is greater than in the sample, the osmotic pressure works towards the solvent flowing into the medium. This flow of solvent would cause the medium to swell. Due to the at least one hollow fiber section, the change in volume of the medium, that is to say in particular a swelling, is however sharply limited; through this is also the Clearly limited uptake of solvent in the medium. As a result, there is a defined uptake of solvent in the medium for a given sensor, regardless of the osmolality of the sample, as long as the osmolality of the sample is lower than the osmolality in the medium. This defined uptake of solvent can be taken into account when calibrating the sensor. This makes calibration of the sensor independent of the osmolality of the sample in which the sensor is used, as long as the osmolality of the sample is lower than the osmolality in the medium.

In one embodiment of the sensor according to the invention, the at least one dye is mixed with a buffer solution, which is then to be regarded as part of the medium. This is mainly used in those sensors in which the sensor effect is based on a pH-value-dependent optical behavior of the at least one dye, and the analyte causes a pH-value change in the medium.

The osmolality in the medium can be adjusted during the manufacture of the sensor by adding at least one substance to the medium. In embodiments, the at least one substance can be mixed with the at least one dye. For example, salts such as NaCl or KCl, polyelectrolytes or neutral molecules such as sugar such as glucose, fructose, mannose, sucrose can be used as substances for adjusting the osmolality in the medium. These added substances are also to be regarded as part of the medium. It is of course important here that the substances added do not interfere with the quantitative detection of the analyte.

The optical behavior of the dye which is used for the quantitative detection of an analyte can, for example, be luminescence, with luminescence comprising at least phosphorescence and fluorescence. Light reflection or light absorption can also be used for quantitative detection of the analyte. Another possibility is to use a color of the dye. The color of the dye, the light reflection or absorption, or the luminescence show a dependency on the analyte. In the case of luminescence, this dependency can consist in the fact that a relaxation time of the luminescence, which can be a relaxation time for the intensity of the luminescence or for a polarization of the luminescence, depends on the analyte. It is also conceivable that the intensity or wavelength of the luminescent light that occurs depends on the analyte. In the case of a color, the dye can take on a different color depending on the concentration or partial pressure of the analyte. In the case of light reflection or absorption, the reflectivity or the degree of absorption of a layer containing the dye can change for certain wavelengths of light as a function of the analyte. More than one type of optical behavior can also be used for the measurement, for example a relaxation time of the luminescence and an absorption behavior. For this purpose, more than one dye can be used, so that, for example, the luminescence behavior of a first dye and the absorption behavior of a second dye are evaluated in order to determine an analyte quantitatively. If more than one dye is used, the efficiency of radiationless energy transfer between the dyes, for example the Förster resonance energy transfer, if this efficiency depends quantitatively on the analyte, can also be used for the quantitative determination of the analyte.

The dependence of the optical behavior on the analyte can result from a direct interaction between the analyte and the at least one dye, for example an energy exchange or a chemical reaction between molecules of the dye and the analyte, or from an indirect interaction via substances added to the dye. General requirement for the functioning of the sensor is therefore that the analyte can enter into such a direct or indirect interaction with the at least one dye. In the case of a sensor according to the invention in which, for example, dye and buffer solution are present in the interior of the at least one hollow fiber section, the analyte must be able to reach the mixture of dye and buffer solution.

Examples of analytes are gases in gaseous mixtures or gases dissolved in liquids. For example, gas dissolved in water, such as sulfur dioxide, carbon dioxide, carbon monoxide or ammonia, can be detected by a sensor according to the invention. Ammonia, which has a basic reaction in water, is an example in which a colorant with a pH-dependent optical behavior can be selected as the colorant for the sensor. Depending on the concentration of the ammonia dissolved in the sample, a pH value is established within the medium, which can be determined from the optical behavior of the dye. In this way, it is possible to draw conclusions about the ammonia concentration indirectly. It goes without saying that a direct calibration of the ammonia concentration against the optical behavior is possible; an actual determination of a pH value is then not necessary. The example of ammonia detection just mentioned is also an example of an indirect interaction between the dye and the analyte, in this case the ammonia. The interaction takes place here via a buffer solution mixed with the dye, in which the analyte adjusts the pH value of the Buffer solution changes, and the optical behavior of the dye depends on the pH value of its environment, in this case the buffer solution. Analogous statements also apply to sulfur dioxide and other gases. An example of a dye with a pH-dependent fluorescence behavior that can be used to detect carbon dioxide is hydroxypyrene trisulfonic acid (HPTS). For example, bromocresol red can be used to measure sulfur dioxide. Bromthymol blue or bromophenol blue can be used for the quantitative detection of ammonia. Numerous other dyes and their possible uses for the quantitative detection of the most varied of substances are sufficiently known to the person skilled in the art.

It should also be pointed out that various possibilities are known for the explicit quantitative determination of the analyte from the optical behavior of the at least one dye via a corresponding calibration. For example, a relaxation time of a luminescence of the at least one dye can be calibrated against partial pressure or concentration of the analyte. Instead of using the relaxation time itself, it is also possible to use variables that are dependent on it and can be determined more easily and directly by experiment, such as quotients of integrals over the time course of luminescence signals or phase shifts between a modulated excitation signal and the luminescence response of the dye. These and other possibilities are adequately described in the prior art, for example in the German patent application DE 10 2011 055 272 A1 and the scriptures cited therein.

However, sensors according to the invention can also be used for the quantitative detection of other dissolved substances, including ions.

In one embodiment of the sensor according to the invention, the at least one hollow fiber section is embedded in a carrier substance. A multiplicity of hollow fiber sections is preferably used, and the carrier substance fixes the hollow fiber sections in relation to one another. In this case, the analyte must be able to get through the carrier substance to the medium in the interior of the at least one hollow fiber section. This can be done, for example, by diffusion of the analyte into the carrier substance. In this context, in one embodiment, the carrier substance is gas-permeable. In embodiments, the carrier substance is hydrophobic. In special configurations, the carrier substance is a polymer or a silicone.

In a special embodiment, the sensor contains a hygroscopic substance. Such embodiments can be used in gaseous samples, for example in the atmosphere. The hygroscopic substance absorbs water from the sample, which is present in the sample as water vapor. This creates an aqueous environment for the at least one dye. It is therefore possible to use dyes and additives such as buffers, which are otherwise limited to aqueous samples, in order to carry out measurements in the gas phase. The hygroscopic substance is preferably mixed with the at least one dye.

In certain embodiments of the sensor according to the invention, the at least one hollow fiber section is made of glass, i.e. it is a section of a glass hollow fiber. Glass has a sufficiently high mechanical stability to effectively mechanically limit the above-mentioned swelling of the medium caused by the osmotic pressure. However, other materials can also be used for the hollow fibers which have sufficient mechanical stability to effectively restrict the swelling of the medium. An effective mechanical restriction of the swelling of the medium is understood to mean that the change in volume of the medium caused by the osmotic pressure is limited to a value at which a measurement error caused by this change in volume remains below a value specified by the manufacturer or user of the sensor, for example a relative measurement error below 5%, preferably below 1% and particularly preferably below 0.1%.

In another embodiment of the sensor according to the invention, the hollow fiber sections are not fixed in a carrier substance, but are provided to be dispersed in a sample. The hollow fiber sections are then movable within the sample. In particular, the hollow fiber sections can float or float in the sample. The ends of the hollow fiber sections are preferably closed, and the material of the hollow fiber sections itself is permeable to the analyte. Hollow fiber sections made of material permeable to the analyte are of course also conceivable in embodiments in which the at least one hollow fiber section is embedded in a carrier substance. The ends of the at least one hollow fiber section can be open or closed.

Regardless of whether the at least one hollow fiber section is embedded in a carrier substance or is intended to be introduced directly into a sample, the ends of the at least one hollow fiber section can each be closed by a plug. Such a plug can consist, for example, of an adhesive, a polymer, a silicone or a wax. The ends of the at least one hollow fiber section can also be closed by caps; Such caps can be glued to the hollow fiber section, for example, or simply pushed onto the ends of the hollow fiber section and held there with a friction fit or a non-thermoplastic plastic such as polyurethane (PU) or polytetrafluoroethylene (PTFE). The material of the plug or the caps can be permeable to the analyte.

Alternatively, the at least one hollow fiber section itself can be shaped in such a way that the ends of the at least one hollow fiber section are closed. If the hollow fiber sections consist of a thermoplastic such as polypropylene (PP), polyethylene (PE), polyvinylidene fluoride (PVDF) or polyethersulfone (PES), the ends of a hollow fiber section can be closed by squeezing with a tool at a sufficiently high temperature. In this context, a temperature is sufficiently high if the respective plastic is plastically deformable at this temperature, so that the material of the hollow fiber section can be deformed by the tool; the temperature required for this depends on the respective plastic. In the case described, the deformation of the material of the hollow fiber section at the ends of the hollow fiber section results in a shape of the hollow fiber section in which the ends of the hollow fiber section are closed.

• Mindestens eine Hohlfaser wird mit einem Medium befüllt. Das Medium ist dabei von der vorstehend beschriebenen Art, das heißt, das Medium enthält wenigstens einen Farbstoff, der ein optisches Verhalten aufweist, welches innerhalb des Sensors durch den Analyten beeinflussbar ist, und das Medium weist eine Osmolalität auf, welche größer ist als eine vorgegebene maximale Probenosmolalität, für die der Sensor vorgesehen ist.

The method according to the invention for producing a sensor for the quantitative detection of an analyte in a sample comprises the following steps:

• At least one hollow fiber is filled with a medium. The medium is of the type described above, that is, the medium contains at least one dye which has an optical behavior that can be influenced by the analyte within the sensor, and the medium has an osmolality which is greater than a predetermined one maximum sample osmolality for which the sensor is intended.

The at least one, now filled, hollow fiber is divided into hollow fiber sections. The dividing can be done, for example, by cutting, sawing, punching or breaking. If the hollow fiber consists of a thermoplastic synthetic material, the division of the hollow fiber can also take place in that sections of the hollow fiber are squeezed off from the rest of the hollow fiber using a tool at a sufficiently high temperature. At the same time, the ends of the hollow fiber sections thus created are deformed, so that the ends of these hollow fiber sections are closed. In this context, a temperature is sufficiently high if the respective plastic is plastically deformable at this temperature, so that the material of the hollow fiber can be deformed by the tool; the temperature required for this depends on the particular plastic. A wire, for example, can be used as a tool for squeezing off; the wire can be brought to the required temperature by an electric current driven through it and kept at this temperature.

The hollow fiber sections are mixed with a carrier substance, for example by stirring; the carrier substance is in a fluid form, for example as a gel or as a liquid. The mixture of hollow fiber sections and carrier substance is distributed over a surface, and finally the carrier substance is hardened. The hollow fiber sections are thus fixed in the carrier substance.

The area over which the mixture of hollow fiber sections and carrier substance is distributed can be the surface of a plate which is intended to function as a carrier plate for the sensor. It is conceivable that the mixture of hollow fiber sections and carrier substance is distributed over a large area over a plate, the carrier substance is then hardened, and then individual sensors are obtained from the plate, for example by cutting, sawing, punching or breaking. For this purpose, predetermined breaking points can be provided in the plate.

In embodiments of the method, the carrier substance is a polymer or a silicone. The curing of the carrier substance can in this case comprise the crosslinking of the polymer chains or silicone chains.

In embodiments, the fluid form of the carrier substance is formed in that the carrier substance is dissolved in a solvent. The hardening of the carrier substance is then brought about by drying the solution of the carrier substance. In particular, the solvent can be evaporated. If the carrier substance is a polymer or a silicone, the polymer or silicone can in particular be dissolved in an organic solvent which is evaporated to harden the carrier substance. Examples of suitable solvents are toluene, tetrahydrofuran (THF), hexane, cyclohexane, chloroform and octane.

According to the embodiments of the sensor according to the invention discussed above, the dye in the medium must be mixed with a buffer solution.

In embodiments of the method, capillary forces are used to fill the at least one hollow fiber. For this purpose, one end of the at least one hollow fiber is immersed in a supply of the medium. The medium with dye is then drawn into the interior of the hollow fiber by the capillary forces. Depending on the configuration of the method, the filling of the at least one hollow fiber can be supported by additional measures, for example by pumping.

In one embodiment of the method, a large number of hollow fibers are filled at the same time. The hollow fibers are in the form of a bundle. One end of the bundle and thus one end of each of the hollow fibers forming the bundle is immersed in the supply of the medium. In this way, the hollow fibers are filled using capillary forces, as mentioned above. The medium penetrates into the bundle but also into the spaces between the hollow fibers, i. H. after filling, the medium is on the outside of the hollow fibers. This is washed off in a subsequent step, but beforehand, in order to protect the medium inside the hollow fibers from the washing process, the ends of the hollow fibers are closed.

After the medium has been washed off the outside of the hollow fibers, the hollow fibers are divided into hollow fiber sections and processed further as already described above.

The medium can contain other substances. In particular, the method according to the invention allows the production of a sensor according to the invention.

• 1 zeigt eine schematische Schnittansicht einer Ausführungsform eines erfindungsgemäßen Sensors.
• 2 zeigt schematisch das Befüllen einer Hohlfaser.
• 3 zeigt schematisch das Befüllen eines Bündels von Hohlfasern.
• 4 zeigt schematisch einen Hohlfaserabschnitt.
• 5 zeigt schematisch einen erfindungsgemäßen Sensor in einer Probe.
• 6 zeigt schematisch eine Ausführungsform des erfindungsgemäßen Sensors, bei dem die Hohlfaserabschnitte des Sensors in einer Probe dispergiert sind.
• 7 zeigt schematisch einen Hohlfaserabschnitt, dessen Enden durch Pfropfen verschlossen sind.
• 8 zeigt schematisch einen Hohlfaserabschnitt, dessen Enden durch Kappen verschlossen sind.
• 9 zeigt schematisch einen Hohlfaserabschnitt, der so geformt ist, dass seine Enden verschlossen sind.

In the following, the invention is explained in more detail on the basis of exemplary embodiments with reference to the accompanying drawings.

• 1 shows a schematic sectional view of an embodiment of a sensor according to the invention.
• 2 shows schematically the filling of a hollow fiber.
• 3 shows schematically the filling of a bundle of hollow fibers.
• 4th shows schematically a hollow fiber section.
• 5 shows schematically a sensor according to the invention in a sample.
• 6th shows schematically an embodiment of the sensor according to the invention, in which the hollow fiber sections of the sensor are dispersed in a sample.
• 7th shows schematically a hollow fiber section, the ends of which are closed by plugs.
• 8th shows schematically a hollow fiber section, the ends of which are closed by caps.
• 9 Figure 4 shows schematically a hollow fiber section which is shaped so that its ends are closed.

1 shows a sectional view of an embodiment of a sensor according to the invention 1 . Hollow fiber sections 4th are embedded in a carrier substance, which here is a polymer 10 is. The hollow fiber sections 4th are with a medium 3 filled. The medium contains a dye not explicitly shown here 2 , which has an optical behavior that occurs within the sensor 1 can be influenced by an analyte. The polymer 10 is on a carrier plate 11 arranged. On the carrier plate 11 opposite side of the polymer 10 is the polymer 10 with a top layer 12th covered.

For example, the carrier plate 11 for when measuring by means of the sensor 1 occurring light wavelengths be transparent. Is it the optical behavior of the dye? 2 about a luminescence, so the carrier plate should 11 be permeable to the light that is used to excite the luminescence and permeable to the luminescent light. The top layer is advantageous in this case 12th designed to be reflective for the light used to excite the luminescence and for the luminescent light. Alternatively, of course, the top layer can also be used 12th be transparent for the corresponding wavelengths of light, and that is what the carrier plate is for 11 designed to be reflective for these light wavelengths.

In any case, the polymer must be 10 , and advantageously also the carrier plate 11 and / or the top layer 12th be permeable to the analyte so that the analyte enters the medium 3 in the in the polymer 10 embedded hollow fiber sections 4th can reach.

The ends 4a and 4b of each hollow fiber section 4th are open in the embodiment shown. Through these open ends 4a and 4b is the medium 3 in the hollow fiber sections 4th definitely accessible once the analyte enters the polymer 10 has penetrated. In addition, the material of the hollow fiber sections 4th even be permeable to the analyte.

One layer thickness 15th of the hollow fiber sections 4th containing layer of the carrier substance, here the polymer 10 , is 200 µm to 300 µm in typical embodiments; however, the invention is expressly not limited to this range of layer thicknesses.

In principle, a sensor according to the invention can also be used without a carrier plate 11 and top layer 12th work, that means in particular that the invention is not limited to the embodiment shown. However, the elements mentioned have advantages. So can a carrier plate 11 , for example made of glass or plastic, the layer made of the polymer 10 with embedded hollow fiber sections 4th mechanically stabilize so that the sensor 1 becomes easier to handle and more resistant to damage. Also the top layer 12th can provide mechanical protection for the layer from the polymer 10 form. A cover layer designed to be reflective for the luminescent light 12th increases the sensitivity of the method, since a higher intensity of the luminescent light is available for the evaluation when luminescent light comes from the cover layer 12th is reflected to a detector. The same applies to the case of a reflective carrier plate 11 .

2 is a schematic representation of the filling of a hollow fiber 5 . An end 5a the hollow fiber 5 is in a supply of the medium 3 submerged. A storage container 12th for the medium 3 is shown symbolically. The medium 3 contains the dye 2 .

Capillary forces become part of the medium 3 with colorant 2 into the hollow fiber 5 sucked in. After the filling process has been completed, there is one with medium 3 and dye 2 filled hollow fiber 5 before which then in hollow fiber sections 4th can be divided.

3 largely corresponds to 2 , just here is a bunch 6th of hollow fibers 5 with which the dye 2 containing medium 3 filled. Any hollow fiber 5 of the bundle 6th is with an end 5a in a supply of the medium 3 submerged. The bundle 6th can be a simple packing together of hollow fibers 5 but it is also possible that the hollow fibers 5 in the bundle 6th are twisted around each other so that the bundle 6th forms a kind of yarn.

Several become a bundle 6th combined hollow fibers 5 filled, medium penetrates 3 also in the spaces between the hollow fibers 5 in a bundle 6th a. Before dividing the filled hollow fibers 5 into hollow fiber sections 4th the bundle is therefore washed or rinsed, around which there are in these interstices and thus on the outside of the hollow fibers 5 located medium 3 to remove. About the medium located inside the hollow fibers 3 to protect from the hollow fibers during the washing or rinsing process 5 to be removed again are the ends 5a and 5b of the hollow fibers 5 closed before washing or rinsing. The hollow fibers cleaned in this way 5 are then cut into hollow fiber sections 4th divided.

4th shows a schematic representation of a section through an embodiment of a hollow fiber section 4th how it can be used in the sensor according to the invention. Inside the hollow fiber section 4th there is dye 2 containing medium 3 . The sensor according to the invention 1 comprises at least one hollow fiber section 4th , for example the embodiment shown here, preferably a plurality of hollow fiber sections 4th . In the method according to the invention are with medium 3 and dye 2 filled hollow fiber sections 4th into a carrier substance, for example a polymer 10 or a silicone, stirred in, which is cured after being applied to a carrier. In one embodiment, an outside diameter is 16 of such a hollow fiber section 10 µm to 12 µm, an inside diameter 17th between 5 µm and 6 µm, and a length 18th of the hollow fiber section between 0.5 mm and 1 mm. It should be emphasized that the invention is not limited to these dimensions of the hollow fiber sections 4th is limited.

5 shows schematically a sample 7th in a sample container 13th . A sensor according to the invention 1 is inside the sample container 13th arranged and in contact with the sample 7th . In particular, the one in the sample 7th included with the sensor 1 to be detected analyte so in the polymer 10 , into the hollow fiber sections 4th and ultimately in the medium 3 arrive at the optical behavior of the medium 3 contained dye 2 to influence. Optical methods are used to investigate the optical behavior. One end of a light guide is symbolic here 14th shown. If the optical behavior is, for example, a luminescence phenomenon, the light guide can be used 14th Light to stimulate the luminescence to the sensor 1 and thus ultimately to the dye 2 and luminescent light can come from the dye 2 via the light guide 14th to be carried out for evaluation.

6th shows a sample 7th in a sample container 13th . In the embodiment of the sensor according to the invention shown here 1 is the multitude of hollow fiber sections 4th of the sensor 1 in the rehearsal 7th dispersed. In the embodiment shown, the ends are 4a , 4b of the hollow fiber sections 4th closed and the material of the hollow fiber sections 4th is permeable to the analyte.

Furthermore, there is an exemplary measuring arrangement 20th shown, which for detecting the optical behavior of the in the hollow fiber sections 4th within the medium 3 contained at least one dye is provided. The measuring arrangement 20th includes a control and evaluation unit 22nd , this associated light sources 24 and also one of the control and evaluation unit 22nd associated camera 26th . The light sources 24 supply light for the evaluation of the optical behavior of the dye, for example light to stimulate a luminescence phenomenon of the dye. The control and evaluation unit 22nd evaluates with the camera 26th recorded images of the sample 7th including the sensor inside 1 and can thereby carry out a quantitative determination of the analyte in a spatially resolved manner. The recorded images contain information about the optical behavior, for example with regard to the luminescence, of the dye in a respective hollow fiber section 4th at a respective location within the sample 7th . The control and evaluation unit intervenes when evaluating the recorded images 22nd advantageous on in the control and evaluation unit 22nd stored calibration data 23 of the sensor 1 return.

The exemplary measuring arrangement 20th shows a basic possibility, such as an embodiment of the sensor according to the invention 1 can be used. However, the sensor according to the invention is not restricted to use with a measuring arrangement of the type shown. It is only important for the use of the sensor according to the invention that an analyte-dependent optical behavior of the in the at least one hollow fiber section 4th present dye can be examined.

7th shows schematically an embodiment of a hollow fiber section 4th as it can be used in the sensor according to the invention. Inside the hollow fiber section 4th there is dye 2 containing medium 3 . In the case of the hollow fiber section shown 4th are the ends 4a and 4b of the hollow fiber section 4th each through a plug 4c locked.

8th shows schematically a further embodiment of a hollow fiber section 4th as it can be used in the sensor according to the invention. Inside the hollow fiber section 4th there is dye 2 containing medium 3 . In the case of the hollow fiber section shown 4th are the ends 4a and 4b of the hollow fiber section 4th each through a cap 4d locked. The cap 4d can for example with the hollow fiber section 4th be glued. But it is also conceivable that the caps 4d on the ends 4a respectively. 4b of the hollow fiber section 4th are attached and are held there frictionally.

9 shows schematically a further embodiment of a hollow fiber section 4th as it can be used in the sensor according to the invention. Inside the hollow fiber section 4th there is dye 2 containing medium 3 . The hollow fiber section shown 4th has a shape through which the ends 4a and 4b of the hollow fiber section 4th are closed. Such a shape can be achieved, for example, by plastic deformation of the material of the hollow fiber section 4th be formed. The material of the hollow fiber section can be used for this purpose 4th locally exposed to an elevated temperature, for example by using a heated tool for deformation. The temperature mentioned must be so high that the material of the hollow fiber section 4th is plastic at this temperature. In particular, this procedure is possible when the hollow fiber section 4th consists of a thermoplastic material. Of course, neither should the dye due to the increased temperature 2 still components of the medium 3 damaged to the extent that the functionality of the sensor is impaired.

Claims (22)

Sensor (1) for the quantitative detection of an analyte in a sample (7), the sensor (1) having at least one dye (2) which has an optical behavior that can be influenced by the analyte within the sensor (1) and a Medium (3) containing the dye (2), characterized by at least one hollow fiber section (4), inside of which the medium (3) with the dye (2) is located, and by an osmolality in the medium (3) , which is greater than a predetermined maximum sample osmolality for which the sensor (1) is intended. Sensor (1) Claim 1 , wherein the dye is mixed with a buffer solution. Sensor (1) according to one of the preceding claims, wherein the osmolality in the medium (3) is set by adding at least one substance to the medium (3). Sensor (1) according to one of the preceding claims, wherein the optical behavior of the at least one dye (2) includes at least one luminescence or one color or one light reflection or one light absorption or one polarization. Sensor (1) according to one of the preceding claims, wherein the at least one hollow fiber section (4) is the section of a glass hollow fiber. Sensor (1) according to one of the preceding claims, wherein the material of the at least one hollow fiber section (4) is permeable to the analyte. Sensor (1) according to one of the preceding claims, wherein the sensor (1) contains a hygroscopic substance. Sensor (1) according to one of the preceding claims, wherein the at least one hollow fiber section (4) is embedded in a carrier substance (10). Sensor (1) Claim 8 , wherein the carrier substance (10) is gas-permeable. Sensor (1) Claim 8 or 9 wherein the carrier substance (10) is hydrophobic. Sensor (1) after one of the Claims 8 until 10 , wherein the carrier substance (10) is a polymer (10) or a silicone. Sensor (1) after one of the Claims 1 until 11 , wherein the ends (4a, 4b) of the at least one hollow fiber section (4) are open. Sensor (1) after one of the Claims 1 until 11 wherein the ends (4a, 4b) of the at least one hollow fiber section (4) are each closed by a plug (4c) or a cap (4d). Sensor (1) after one of the Claims 1 until 11 wherein the at least one hollow fiber section (4) is shaped such that the ends (4a, 4b) of the at least one hollow fiber section (4) are closed. Sensor (1) according to one of the preceding claims, wherein the sensor (1) comprises a plurality of hollow fiber sections (4), in the interior of which the medium (3) is located. A method for producing a sensor (1) for the quantitative detection of an analyte in a sample (7), comprising the steps: a) filling at least one hollow fiber (5) with a medium (3), the medium (3) containing at least one dye (2) which has an optical behavior which can be influenced by the analyte within the sensor (1), and wherein the medium (3) has an osmolality which is greater than a predetermined maximum sample osmolality for which the sensor (1) is provided; b) dividing the filled at least one hollow fiber (5) into hollow fiber sections (4); c) mixing the hollow fiber sections (4) with a fluid form of a carrier substance (10); d) distributing the hollow fiber sections (4) mixed with the carrier substance (10) over a surface; and e) hardening of the carrier substance (10). Procedure according to Claim 16 wherein the dye (2) is mixed with a buffer solution. Procedure according to Claim 16 or 17th wherein the filling of the at least one hollow fiber (5) with the medium (3) utilizes capillary forces, and one end (5a) of the at least one hollow fiber (5) is immersed in a supply of the medium (3). Procedure according to Claim 18 , wherein a plurality of hollow fibers (5) in the form of a bundle (6) with one end (5a) is immersed in the supply of the medium (3), after the hollow fibers (5) have been filled with the medium (3) the ends ( 5a, 5b) of the hollow fibers (5) are closed and the medium (3) located between the hollow fibers (5) is washed off before the hollow fibers (5) are divided into hollow fiber sections (4) according to step b). Method according to one of the Claims 16 until 19th , wherein the carrier substance (10) is a polymer (10) or a silicone. Method according to one of the Claims 16 until 20th , wherein the division of the filled hollow fiber (5) into hollow fiber sections (4) takes place in that hollow fiber sections (4) are squeezed off from the hollow fiber (5) by a tool which has a temperature at which the material of the hollow fiber (5) plastically is deformable. Using a sensor (1) Claim 15 wherein the plurality of hollow fiber sections (4) are dispersed in the sample (7).

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