EP2173235A1 - Capteur de concentration de substance et son procédé de production - Google Patents

Capteur de concentration de substance et son procédé de production

Info

Publication number
EP2173235A1
EP2173235A1 EP08759093A EP08759093A EP2173235A1 EP 2173235 A1 EP2173235 A1 EP 2173235A1 EP 08759093 A EP08759093 A EP 08759093A EP 08759093 A EP08759093 A EP 08759093A EP 2173235 A1 EP2173235 A1 EP 2173235A1
Authority
EP
European Patent Office
Prior art keywords
receiver
sensor according
measuring
substance
measuring chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08759093A
Other languages
German (de)
English (en)
Inventor
Kai-Uwe Zirk
Hans-Joachim Freitag
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ses-Entwicklung GmbH
SES Entwicklung GmbH
Original Assignee
Ses-Entwicklung GmbH
SES Entwicklung GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ses-Entwicklung GmbH, SES Entwicklung GmbH filed Critical Ses-Entwicklung GmbH
Publication of EP2173235A1 publication Critical patent/EP2173235A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/14532—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring glucose, e.g. by tissue impedance measurement
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/14546—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring analytes not otherwise provided for, e.g. ions, cytochromes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14558—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters by polarisation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
    • A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
    • A61B5/6848—Needles
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
    • A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
    • A61B5/6848—Needles
    • A61B5/6849—Needles in combination with a needle set
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/21—Polarisation-affecting properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/85—Investigating moving fluids or granular solids
    • G01N21/8507—Probe photometers, i.e. with optical measuring part dipped into fluid sample
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • G01N21/031—Multipass arrangements

Definitions

  • the present invention relates to a sensor for determining a concentration of a substance in a liquid or liquid-containing matrix, comprising a measuring chamber, a transmitter for emitting optical radiation into the measuring chamber and a receiver for receiving optical radiation passed through the measuring chamber. and to a manufacturing method for such a sensor.
  • the invention relates to a sensor of a unitary system with integrated in the measuring chamber transmitter and receiver, and preferred embodiments thereof.
  • the measurement of substance concentrations is a frequently encountered technical task. It then encounters particular difficulties when the substance to be measured is present in a mixture of other substances. Such a matrix means that not only the highest possible sensitivity, but also the highest possible selectivity of the measuring method is needed for a precise concentration measurement. Often therefore one does not get by with a single measurement or must use very expensive selection mechanisms, such as gas chromatography, etc.
  • the difficulty of the measurement task increases with the complexity of the matrix. Very complex mixtures are naturally found in biological systems. The measurement of a substance concentration in a biological matrix is therefore one of the most complex tasks.
  • miniaturized material sensors are of particular interest for biological applications. As is known, it is vital that in humans some substances such. As glucose, saline, uric acid, amino acids, etc., in a controlled concentration. In case of illness, however, it can lead to a derailment of the biological control loop, so that the substance concentration of one or more vital substances is outside the physiologically acceptable range. In order to counteract such derailment by therapeutic measures, the value of the current concentration of the corresponding substance (s) must be known to the attending physician; the concentration must therefore be measured, and sometimes continuously.
  • glucose level assumes too high (hypoglycaemia) or too low (low blood glucose) levels.
  • hyperglycaemia hyperglycaemia
  • low blood glucose low blood glucose
  • Consequences such as blindness, loss of kidney function, myocardial infarction, high blood pressure and a death of limbs can be the result.
  • Diabetes therapy therefore requires that the level of glucose be adjusted as accurately and consistently as possible to values within a medically acceptable range, e.g. B. by administration of insulin or glucose.
  • the time and amount of insulin to be injected, or the need to eat depends on the current concentration of glucose as well as on the course of the concentration during the day.
  • the glucose concentration is thus an example of a substance concentration in a complex matrix, which one wishes to control as continuously as possible, without any time interruption and without elaborately recurring adaptation measures.
  • all current therapies are dedicated to influencing blood glucose levels, which is why most glucose concentration measuring devices also determine the level of glucose in the blood.
  • it is also known to use the interstitial fluid since its glucose content proportionally follows that of the blood with only a slight delay.
  • a measuring device for polarimetric continuous glucose determination is disclosed for this purpose, wherein a measuring and a comparison cuvette are used, which are partially equipped with a membrane for an ultrafiltration. The technically very complex coupling of the membrane to the cuvette is not disclosed. From the difference in intensity of the measuring and the comparison beam, the respective concentration of the ultrafiltrate is obtained.
  • DE 19911265 C2 a device is provided for measuring the glucose concentration of protein-containing aqueous solutions, in particular in interstitial tissue fluids. described in which a dialysate is simultaneously analyzed polarimetrically and spectrometrically.
  • the technical complexity here by the parallel use of two measuring methods enormously large. The device described can also expect a large size.
  • a dialysis membrane made of plastic for carrying out a substance separation is mentioned, but its technically very complicated coupling to the optical measuring system is not disclosed in detail.
  • the generic document DE 10321356 A1 discloses a method in which the determination of the substance concentrations of optically active constituents in media takes place by passing a measuring beam from a radiation source to a coupling unit, where it is coupled into a measuring space, after penetrating the measuring space at a reflection unit undergoes a direction reversal, again crossed the measuring space and again occurs at the coupling unit.
  • the technical complexity for the use of reflection and beam splitter units is very large. It is also unclear how this process should be used to determine a substance in a matrix of other substances.
  • the tissue or the Eisengewebeirrikeit represents the matrix.
  • a sensor would be particularly advantageous, which can be introduced directly into the tissue, since then a continuous concentration monitoring of the selected substance is possible. This is not possible with the known generic devices.
  • a sensor for determining a concentration of a substance present in a liquid or liquid-containing matrix with a measuring chamber, a transmitter for emitting optical radiation in the Measuring chamber and a receiver for receiving optical radiation passed through the measuring chamber, wherein transmitter and receiver are used as part of the wall of the measuring chamber to provide a unit which is adapted for introduction into the matrix, the measuring chamber filled with a measuring medium and their Wall at least partially better diffusion permeable for the substance than for matrix components to compensate for differences in concentration of the substance between the measuring chamber and the matrix, and a control and evaluation circuit is provided, which is connected to the transmitter for driving it and the receiver for reading receiver signals and determining from the receiver signal a measure of the concentration of the substance in the matrix.
  • the senor according to the invention is based on the measurement principle of DE 10321356 A1 and thereby substantially expands it by separating off the substance in the matrix by selective diffusion.
  • the sensor thus realizes a defined concentration equalization of the substance in the matrix and the measuring medium in the interior of the measuring chamber and at the same time an optical measurement in the measuring chamber, resulting in a total of a compact unit.
  • the sensor works without moving parts and can be easily designed as a puncture probe.
  • the invention particularly includes a sensor
  • the sensor solves the prior art problem of low specificity with which a purely physical measuring method is usually associated. Due to the diffusion-related separation of the substance from the matrix of the sensor comes out with a simple optical measurement setup and can thus be kept very compact.
  • the wall thus selects the substance from the matrix by virtue of its diffusion properties (substance separation properties), in that it is separated from other matrix constituents.
  • the material separation can be carried out by a size and / or a shape selection, d. H.
  • the wall allows only substances in a certain size range or a specific shape range of their molecules to pass.
  • the senor allows a simple optical measurement by means of a defined substance separation, because the sensor has a preferably mechanically stable, on but in any case has a material diffusion-permeable wall, which causes a dynamic approximation of the concentration of the substance in the measuring medium to that in the matrix (for example, intercellular fluid).
  • Preference is given to an elongated housing for constructing the measuring chamber, which also simultaneously receives the transmitter and receiver necessary for the optical measurement. Due to the material-separating functionality of the sensor, the optical measuring method is substantially simplified, which allows a compact, miniaturizable and cost-effective implementation. In particular, it can be prevented by the diffusive substance separation that substances which also act on the optical measurement method used and possibly to a much greater degree than the substance to be detected, get into the measuring chamber.
  • the diffusion properties of the Meßhuntwandung are preferably chosen so that a good diffusion and thus a good passage is given only for the substance to be measured, but not for other substances of the matrix to be measured. It is therefore entirely within the scope of the invention also possible to predetermine or adjust the diffusion properties of the wall suitable for the matrix and the substance in the design of the sensor.
  • the diffusion properties of the wall provide the desired selectivity of the sensor, so that the optical measurement taking place in the measuring chamber achieves a high specificity for the substance, without the need for complicated optical structures.
  • the electromagnetic, optical measuring beam generated by the transmitter eg with wavelengths between 0.3 and 1.5 ⁇ m
  • the transmitter predeterminable polarization states (non-, partially, linearly, elliptically or circularly polarized) and / or wavelength distribution of the measuring beam, it is possible to specify the type of measuring method (polarimetry or absorption or scattered light measurement) for the sensor and thus the Sensor to adapt to one or more substances.
  • the measuring beam after passing through the measuring medium, strikes the receiver, which consists of one or preferably at least two independent units.
  • the receiver which consists of one or preferably at least two independent units.
  • the diffusion selection reduces / prevents cross influences of substances of the matrix, whereby the structure can be kept compact.
  • it is no longer absolutely necessary to reflect the measuring beam in the measuring chamber, as is still described in DE 10321356 A1 for Meßumblenverlinirung. Of course, this is possible for a short setup.
  • the measuring chamber may preferably by an elongated housing, for.
  • a tube to be formed at one end face of the transmitter and attached to its opposite end face of the receiver.
  • the cross section of the elongated housing influences the diffusion compensation (diffusion time) and should therefore advantageously be chosen as small as possible, whereby a narrow housing can be realized, preferably with a diameter of less than 3 mm.
  • Such a trained sensor can then be realized by suitable design of the housing as a puncture probe and has short diffusion times (set times).
  • the measuring medium stored in the measuring chamber is of importance for the diffusion properties of the substance through the wall.
  • the measuring chamber must of course be tight for a long-lasting measuring capability for the measuring medium. This can be realized with particularly little effort if the transmitter and the receiver are glued tightly in and / or on the end faces to the housing. Then, with few components, the interior of the sensor for the measuring medium can be made dense.
  • the measuring chamber should be filled bubble-free with the measuring medium in order to avoid disturbing reflections and scattering of the optical radiation and / or to use the distance of the radiation between transmitter to receiver as optimally as possible.
  • a filling can be realized simply by placing the unfilled sensor in an evacuated chamber into which the measuring medium is admitted. This automatically fills the sensor with a suitable liquid.
  • the control and evaluation circuit should be as close as possible to the sensor in terms of a compact design as possible. For technical reasons, an attachment of the circuit near the receiver is advantageous because then weak receiver signals can be read well.
  • the contact with the then spaced station can be done on the outside of the housing, if corresponding tracks are provided.
  • the electronics or a part thereof can also be arranged on the transmitter side.
  • a particularly simple installation of these conductor tracks can be achieved if the housing has at least two grooves extending between the end faces, into each of which a conductor track, preferably a thick-film conductor, is made is.
  • the thick-film technique for producing the conductor tracks is particularly suitable when the wall has a porous material, in particular a ceramic, silicon, plastic, glass or metal, at least in the diffusion-permeable sections, but in particular the entire housing.
  • This coating can be applied, for example, in a sol-gel process or a bedding process or a deposition process. This approach allows a preparation of several housing parts in a long strand, from which the individual housing, for. B. tubes then only have to be cut to length.
  • the optical measurement in the measuring chamber is, of course, chosen to match the substance to be detected and the measuring medium in the chamber.
  • One possible optical measurement is a photometric method. Photometric methods are distinguished from other analytical methods by high sensitivity, simplicity and the possibility of large series tests under standardized conditions.
  • absorption photometry z. As ultraviolet or visible radiation. This spectral range corresponds to changes in the energy of the valence electrons. It is also possible to use the infrared spectral range, in which changes in the nuclear vibrational energy occur in molecules of the substance to be detected. However, only a small proportion of the substances to be examined shows absorption bands in the light (color) or in the ultraviolet range.
  • the chemical reaction can be initiated by diffusing the substance into the liquid of the chamber. For example, after appropriate workup, the following can be detected: ketone bodies, bilirubin, cholesterol, Iron, bile acid, hemoglobin, uric acid, carbon monoxide, residual nitrogen in the blood, etc ..
  • Another possible optical measurement is based on a polarimetric method, in which case the substance to be detected must be optically active, which applies, for example, to glucose.
  • the optical measuring method in the sensor according to the invention can not only evaluate a polarization rotation, as in the example of glucose, but also, as described above, an absorption, ie a transmission attenuation, as z. B. in the case of lactose or uric acid in question. Also, a transmission attenuation can be evaluated by scattering.
  • the measuring medium in the chamber ie z.
  • the liquid is therefore sometimes dependent on the measurement method to choose from the substance and / or from the matrix.
  • it may be chosen so that it contains the substance to be measured in a standard concentration.
  • the receiver signal then shows z. B. deviations from the standard concentration.
  • a physiological saline solution or a glucose solution may be used as the fluid.
  • the measuring medium may also be a gas or gel.
  • the transmitter has at least one radiation source and an optical filter system or an imaging system or both.
  • the imaging system ensures optimum passage of the radiation through the measuring chamber and, in particular, adapts the optical radiation emitted by the radiation source to the cross section and the length of the measuring chamber. It may include, for example, a collimator optics.
  • the radiation source can be designed as a light-emitting diode, laser diode or light emitting diode array.
  • the filter system is tuned to the evaluated optical effect, which may include, for example, broadband absorption, wavelength-selective absorption, polarization-dependent absorption or polarization rotation. It is therefore expedient that the filter system comprises a polarizing filter and / or an interference filter and / or an edge filter.
  • the receiver side comprises in the simplest case a photosensitive element for a measuring method. A particularly high accuracy of measurement can be achieved if a quotient and / or difference analysis is performed on the receiver side. It is therefore preferred that the receiver comprise at least two photosensitive elements and at least one optical filter system which matches the transmitter-side filter system. Another possibility is to use two different optical effects with two photosensitive elements.
  • the evaluation circuit determines the concentration of the substance from the signal change caused by the change in radiation caused by the passage of the measuring medium.
  • the approach according to the invention can be further refined if the measuring chamber still contains at least one further closed chamber whose dividing wall is diffusion-permeable only for some of the substances for which the wall of the measuring chamber is permeable to the outside. If one looks then also a transmitter and a receiver for this further measuring chamber, an improved measurement can take place.
  • the sensor according to the invention can be produced very simply, as already stated above. It is therefore provided in the context of the invention, a manufacturing method for a sensor of the type mentioned, in which an elongated housing made of porous material, in particular ceramic, silicon, plastic, glass or metal, inside and / or outside with a coating prepared, for example in a sol-gel process or a sputtering process or a deposition process, which gives the wall certain diffusion properties for a selected substance.
  • the sensor may be formed as a puncture probe, z. B. for measuring the glucose, urea or lactose content in mammals, especially in humans.
  • Figs. 1-11 shown in the drawings show:
  • FIG. 1 is a schematic representation of a sensor for measuring a substance concentration in a liquid
  • Fig. 2 is a transmission curve for a wall of the sensor of Fig. 1
  • FIG. 3 shows a modified sensor similar to that of FIG. 1,
  • FIG. 6 is a sectional view through the wall of the sensor of FIG. 4
  • FIG. 7 is a schematic diagram relating to the mounting of the sensor of FIGS. 1 and 3 to 5
  • Fig. 11 shows a further sensor variant with two measuring chambers.
  • FIG. 1 shows schematically a longitudinal section through a sensor 1 for the specific, continuous and absolute determination of the concentration of a substance in a matrix, eg. B. the glucose concentration in a biological tissue.
  • the sensor 1 uses an optical measuring principle, as will be explained. He has a mechanically stable housing 2, which is formed in the embodiment as a tube. At the front sides of the housing 2 there are a transmitter 3 and a receiver 4. The housing 2 is thereby sealed liquid-tight at its end faces, since the transmitter 3 and the receiver 4 connected to the end faces accordingly, z. B. are glued. In the schematic illustration of Fig. 1 it can be seen that in the embodiment chosen here, the two components are glued to the end faces.
  • the housing a measuring chamber 5.
  • the thus completed measuring chamber 5 is filled with a known liquid (measuring medium).
  • the wall of the housing 2 allows a diffusive mass balance between the surrounding matrix and the measuring medium in the measuring chamber 5, bidirectional and material-selective. The selection is chosen so that, if possible, only the substance to be detected can diffuse through the wall of the housing 2, or at least one order of magnitude higher diffusion coefficient than the remaining substances of the matrix, as far as these substances act on the still to be explained measuring effect.
  • the diffusion path is illustrated in Fig. 1 and the other Figs. 3 to 5 by a double arrow.
  • An emitted from the transmitter 3 optical beam 6 can be detected directly by the receiver 4 after passing through the medium and any interaction with substances contained therein.
  • the attenuation of the intensity of the optical beam 6 depends on the absorption behavior of the substance in the liquid.
  • the absorption is linked in a known manner with the substance concentration, so that from the intensity of the optical beam at the receiver 4 and thus from the size of the receiver signal directly a conclusion on the substance concentration is possible.
  • the construction of FIG. 1 is therefore particularly suitable for substances which influence the absorption.
  • Transmitter 3 and receiver 4 are both connected to an electronic control unit 7, which on the one hand controls the transmitter 3 and on the other hand reads the receiver 4.
  • a simple two-point calibration is possible.
  • one reads out the value of the receiver 4 at two known substance concentrations.
  • the concentration chosen is zero and the normal solution. From these two measured values results in a good approximation, a linear sensor characteristic for the absolute measurement of the substance concentration.
  • a recalibration is possible in a simple manner while knowing the interaction of the radiation with the liquid before the first use, so that the subsequent measurement takes place as an absolute measurement, since the deviation from the previous calibration is detected.
  • Fig. 2 illustrates the effect of diffusion.
  • the permeability D is plotted as a function of the size g of a substance.
  • the wall of the housing 2 allows substances with a size smaller than the size gl in the interior of the measuring chamber 5, ie the housing 2, whereas substances which are larger, are not allowed to pass.
  • An exemplary value for the size gl is z. B. 30 kDalton.
  • glucose may diffuse into the fluid 5, larger Substances such. B. proteins, which would show a greater effect, for example, with regard to the still to be explained measuring effect, however, can not penetrate into the measuring medium.
  • the housing 2 here also serves as a mechanical link between the transmitters 3 and receivers 4 provided for the optical measurement, which are fastened to the ends of the housing and thus form part of the wall of the measuring chamber 5.
  • Fig. 3 shows a modified construction of Fig. 1. Only the electronics 7 is placed in extension of the elongated housing 2 on the front page for miniaturization. In the illustrated construction, the electronics 7 is located on the transmitter-side end face. The electronics 7 preferably continues the outline of the housing 2 or is only slightly above. However, it is now an electrical Kontak- tion to the other end face required at the sitting in the construction of Fig. 3, the receiver 4. There are at least two printed conductors 8 laid along the housing 2, which extends on the outer wall, in the wall or along the inner wall.
  • Fig. 4 shows a construction similar to that of Fig. 3, but with the electronics 7 now on the receiver side.
  • transmitter 3 and receiver 4 are no longer glued to the end faces of the tube, but glued the front side into the elongated housing 2.
  • the sensor 1 is designed here as a puncture probe by having a tip 19 on the end face.
  • the transmitter 3 additionally adds an imaging system 9 and a filter system 10, which are arranged upstream of the radiation source.
  • the imaging system 9 can be designed, for example, as collimator optics and ensures that the optical radiation 6 is distributed as homogeneously as possible and emitted to the receiver 4.
  • the filter system 10 can be for example a polarization filter, an interference filter or an edge filter.
  • the design of the optical filter system 10 determines the nature of the measurement method. For example, in a polarimetric measuring method, the filter system 10 will have a polarizing filter. An optical receiver filter system 11 matching the transmitter-side optical filter system 10 is arranged in the receiver 4. Of course both can Filter systems not only have a single filter type, but also a combination of different filters.
  • Fig. 5 shows a development of the sensor 1 of Fig. 4.
  • two independent receiver units 4a and 4b are provided, which allow independent evaluation of the optical measuring beam according to two criteria. For example, a polarimetric rotation or else wavelength-dependent absorption or both can be evaluated simultaneously.
  • the filter systems 11a, 11b upstream of the receivers 4a, 4b are tuned to the respective measuring method (s).
  • the structure of FIG. 5 allows z.
  • a polarimetric differential measurement for example, if two polarizing filters are used, the polarization direction is rotated by 90 ° to each other and at 45 ° to the transmitter polarization filter 10.
  • FIG. 6 shows a cross section through the elongated housing 2.
  • the elongated housing 2 and thus the measuring chamber 5 has a rectangular cross-section.
  • two grooves 14 are introduced, which extend along the housing longitudinal axis and thus substantially parallel to the direction of the optical beam 6 (in Fig. 6 perpendicular to the plane).
  • thick-film conductors 15 are introduced (in the lower groove is drawn for the sake of clarity, no thick-film conductor).
  • the groove 14 facilitates the manufacture of the thick film conductor 15, since the conductive paste can be simply scraped; In addition, it protects the conductor 15 from mechanical damage.
  • the carrier body 12 is preferably made of a porous material which has no diffusion properties which are selective for the substance to be detected, but which is as neutral as possible with regard to its diffusion properties. As a material come porous ceramic, silicon, plastic, glass or metal in question.
  • the inner wall of the square cross-section is also other cross-sections such as rectangular, polygonal, round etc.
  • a coating 13 eg a carbon or ceramic coating
  • the coating 13 is set to diffusion-selective, ie has a substance-dependent diffusion coefficient, which significantly promotes the substance to be detected during the diffusion.
  • the coating is a close-meshed filter that blocks off any substance larger than the substance to be detected (eg glucose).
  • the substance to be detected can therefore diffuse much better through the composite structure of the wall of the measuring chamber 5, as such other substances.
  • the substance to be detected diffuses into and out of the liquid, so that a change in the composition takes place directly and only by the substance to be detected.
  • the sensor 1 hangs on a cover 17 of a bearing housing 16.
  • a bearing housing 16 is provided, in which the sensor 1 is inserted and as shown in FIG. 7 hangs on a lid.
  • the bearing housing 16 is completely filled with liquid 18, which is preferably exactly the liquid which is also located in the interior of the sensor 1.
  • a calibration of the sensor 1 can take place in the bearing housing 16.
  • FIGS. 8 and 9 show, in a preferred embodiment, that the lid 17 can be designed such that it serves as a housing cap on the corresponding front side of the sensor 1 and also remains there when the sensor is used.
  • the lid 17 is here designed as a semicircular cap, which are connected via elastic connecting webs or membranes 20 with the sensor 1.
  • the cap also has a signal transmission means 22, z.
  • Example in the form of a radio transmitter or a plug which is connected via a cable 23 through the cap to the electronics 7, so that the lid 17 also provides the connection means for the sensor 1.
  • the elastic connection via the membranes 20 causes the probe 1 formed as a probing probe can also be inserted obliquely, so that the longitudinal axis of the sensor 1 relative to the cover 17 are pivoted can transmit to the sensor 1 without disturbing forces.
  • the lid 17 can also be designed obliquely.
  • Such mechanical decoupling between cover 17 and housing 2 significantly increases the mechanical stability when using the sensor as a puncture probe.
  • the sensor 1 is formed as a puncture probe by the tip 19 provided on the front side and can be inserted into suitable tissue (eg subcutaneous fatty tissue). There he can stay for a longer period of time (a few days) and continuously measure.
  • Fig. 10 shows an alternative construction of the sensor 1, in which in the measuring chamber on the front side of the housing 2, a reflection layer 24 is arranged and
  • Transmitter 3 and receiver 4 are located on the opposite end face of the housing 2.
  • the optical radiation 6 is thus reflected at the reflection layer 24.
  • the described sensor principle can of course also be implemented with two sensors 1 for quotient and / or difference formation or a dual-chamber sensor whose chamber walls have different diffusion properties.
  • at least one additional chamber 25 is provided in the measuring chamber 5, which is delimited from the measuring chamber 5 by one or more inner walls 26.
  • the diffusion properties of these inner walls differ from the diffusion properties of the (outer) wall of the measuring chamber 5.
  • the inner wall 26 passes only a portion of those substances that can diffuse through the (outer) wall of the housing 2.
  • Fig. 11 illustrates this different diffusion behavior with 2 double arrows for the wall of the housing 2 and only a double arrow for the wall 26.
  • This structure causes, only a part of the substances that are in the measuring chamber 5, in the inner, further measuring chamber 25 einiffunidieren. A more refined measurement methodology is the result.
  • a transmitter 3a or 3b is provided both for the (outer) measuring chamber 5 and for the (inner) measuring chamber 25, and a receiver 4a or 4b detects the run through the respective chamber Radiation.
  • the arrangement of the chambers can be chosen arbitrarily within the scope of the technically possible, as long as it is ensured that in the (inner) further chamber 25 only a part of those substances can diffuse, which can diffuse into the (outer) measuring chamber 5.
  • the measuring chamber 5 may include an inner chamber 25 of smaller cross-section which is suitably supported in the measuring chamber 5 (eg at the end faces). It is also possible in the measuring chamber 5 to attach two partitions tight, which delimit the further chamber 25.
  • a common transmitter 3 can be used for both chambers, which then extends, for example, over the end faces of both chambers. If, for example, a spatially resolving receiver is used, this concept can also be followed on the receiver side.
  • the illustration of Fig. 11 is to be understood in this regard only as an example and should not be construed as limiting. Also, in Fig. 11 for the sake of simplicity, the electrical contacts from the controller 7 to the transmitter or to the transmitters are not shown. These can run on the outer wall and / or on the partition wall.
  • the invention relates in particular to a sensor for determining the concentration of a substance contained in a liquid-containing or liquid matrix, with a measuring chamber 5, a transmitter 3 for emitting optical radiation 6 in the measuring chamber 5 and a receiver 4 for receiving run through the measuring chamber optical Radiation 6, which is characterized in that transmitter 3 and receiver 4 each form part of the front side or the opposite side of the measuring chamber 5 and this is at least partially substantially diffusion permeable to the substance to be measured substantially, these from 3, 4 and 5 formed unit at least in the diffusion-permeable portions of a porous material 12, selected from silicon, glass, ceramic, plastic, metal, especially ceramic is formed, and the sensor further comprises a control and evaluation circuit 7, with the transmitter 3 to the On control and the receiver 4 z is connected to read out receiver signals and determines from the receiver signal a measure of the concentration of the substance in the matrix.
  • the porous material 12 of the unit 3, 4 and 5 preferably has a diffusion-conferring coating 13, in particular of titanium dioxide materials, inside and / or outside.

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Abstract

L'invention concerne un capteur servant à déterminer la concentration d'une substance se trouvant dans une matrice contenant un liquide. Le capteur selon l'invention comprend une chambre de mesure (5), un émetteur (3) servant à émettre un rayonnement optique (6) dans la chambre de mesure, ainsi qu'un récepteur (4) recevant le rayonnement optique ayant parcouru la chambre de mesure. Selon l'invention, la chambre de mesure est conçue pour être introduite dans la matrice, est remplie d'un liquide défini et sa paroi (12, 13) permet au moins par endroits la diffusion de la substance. Un circuit de commande et d'évaluation (7) est relié à l'émetteur (3) afin de le commander et au récepteur (4) afin de lire les signaux du récepteur et détermine à partir du signal du récepteur une valeur pour la concentration de la substance dans la matrice.
EP08759093A 2007-07-05 2008-06-07 Capteur de concentration de substance et son procédé de production Withdrawn EP2173235A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007031284A DE102007031284A1 (de) 2007-07-05 2007-07-05 Stoffkonzentrations-Sensor und Herstellverfahren dafür
PCT/EP2008/004556 WO2009015723A1 (fr) 2007-07-05 2008-06-07 Capteur de concentration de substance et son procédé de production

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EP2173235A1 true EP2173235A1 (fr) 2010-04-14

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US (1) US8213013B2 (fr)
EP (1) EP2173235A1 (fr)
DE (1) DE102007031284A1 (fr)
WO (1) WO2009015723A1 (fr)

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US7936463B2 (en) 2007-02-05 2011-05-03 Palo Alto Research Center Incorporated Containing analyte in optical cavity structures
US7633629B2 (en) 2007-02-05 2009-12-15 Palo Alto Research Center Incorporated Tuning optical cavities
US7852490B2 (en) 2007-02-05 2010-12-14 Palo Alto Research Center Incorporated Implanting optical cavity structures
US8320983B2 (en) 2007-12-17 2012-11-27 Palo Alto Research Center Incorporated Controlling transfer of objects affecting optical characteristics
DE102011087679B3 (de) * 2011-12-02 2013-04-18 Schildtec GmbH Meßkammer für einen optisch arbeitenden Sensor zum Bestimmen einer Konzentration eines Stoffes
DE102012214502B4 (de) * 2012-08-14 2014-07-10 Schildtec GmbH Messkammer für einen optisch arbeitenden Sensor, Herstellverfahren für die Messkammer sowie optisch arbeitender Sensor
DE102012221592B4 (de) 2012-11-26 2014-08-14 Schildtec GmbH Herstellverfahren für eine strahlumlenkende, phasenschiebende, optische Anordnung und damit hergestellte Anordnung
EA031910B1 (ru) 2013-10-24 2019-03-29 Оутотек (Финлэнд) Ой Способ эксплуатации сернокислотной установки
US10349167B2 (en) * 2015-05-18 2019-07-09 Apple Inc. Audio speaker with back volume containing adsorptive material
CN109864746B (zh) * 2017-12-01 2023-09-29 心脏起搏器股份公司 用于医学装置的多模式分析物传感器

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WO2009015723A1 (fr) 2009-02-05
US8213013B2 (en) 2012-07-03
US20100134798A1 (en) 2010-06-03
DE102007031284A1 (de) 2009-01-08

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