Devices for operating biosensors and equipment for determining glucose levels in blood.

Abstract

This invention relates to an apparatus for operating a biosensor (01) that emits radiation. The apparatus includes an excitation light source (03) that generates at least one excitation radiation for the biosensor; a coupling fiber (04) into which the excitation radiation is coupled at its incident surface; an optical Y-coupler (12) having an excitation arm (11) coupled to the exit surface of the coupling fiber (04), a detector arm (13) coupled to an optical detector (21), and a sensor base (14) that can be coupled to the biosensor (01). The excitation arm (11) has a tapered shape. The beam axis of the excitation arm (11) forms an angle between 5° and 70° with the main beam axis of the detector arm (13). The diameter of the excitation arm (11) at its connection point (16) with the detector arm is less than two-thirds the diameter of the detector arm (13). The invention also relates to a device for determining glucose levels, particularly in blood.

Description

Technical Field

[0001] This invention relates to fiber optic devices for operating biosensors. Biosensors are, in particular, but not only applicable to determining the glucose content in blood. Therefore, this invention also relates to devices for determining the glucose content in blood. Background Technology

[0002] Optical sensors are also used to evaluate fluorescence radiation. In many cases, the optical device provides the excitation radiation and evaluates the radiation emitted by a suitable luminescent material. The intensity of the emitted fluorescence radiation can be a measure of the parameter to be monitored.

[0003] Therefore, DE 10 2015 101 847 B4 describes, for example, an apparatus for examining a sample that can be excited by electromagnetic radiation. To separate the excitation radiation from the emitted measurement radiation, the apparatus has a first dichroic beamsplitter having first and second prisms interconnected on their base surfaces and a dichroic layer disposed between the base surfaces of the two prisms. A light source provides electromagnetic radiation suitable for exciting the sample, which is coupled to the incident surface of the first prism. A portion of the radiation is reflected in the dichroic layer toward the sample, which is positioned behind the exit surface of the first prism. A detector is used to detect the electromagnetic measurement radiation emitted by the sample, guided through the beamsplitter, and exiting the beamsplitter at the measurement surface. The disadvantages of this arrangement are its sensitive and relatively large structure, which, for example, cannot be used under normal circumstances, and appears unusable by untrained personnel.

[0004] In “First clinical evaluation of a new percutaneous optical fiber glucose sensor for continuous glucose monitoring in diabetes”, Müller AJ, Knuth M, Nikolaus KS, Krivánek R, Küster F, Hasslacher C, Journal of Diabetes Science and Technology, 2013; 7(1): 13-23, January 1, 2013, a device with a glucose-sensitive sensor is described, which is constructed as a biosensor at the end of an optical fiber. For this purpose, one or more fluorescent luminescent materials are arranged on the optical fiber and excited by excitation radiation. The excitation radiation is provided by an LED and coupled into the optical fiber through a lens. In a specific application, the intensity of the emitted fluorescent radiation depends on the glucose content in the blood of the tissue into which the fiber can be implanted. The emitted fluorescent radiation is guided in the optical fiber to a detector and evaluated by the detector. In principle, this biosensor is suitable for quasi-continuous measurement of blood glucose levels, allowing the provided values ​​to be delivered, for example, to an insulin dispensing unit for insulin delivery to the patient as needed. However, the guidance of excitation radiation and the assessment of fluorescence radiation provided by the biosensor are technically difficult to achieve in a minimal unit, thus forcing patients to carry larger devices.

[0005] DE 694 08 976 T2 describes a glucose monitor comprising a light source, a sensor, and a processor. The light source emits excitation light directed at the sample to induce fluorescence in the glucose within the sample. The excitation light results in the sample producing backlighting, which contains fluorescence generated by any glucose in the sample. The sensor monitors the return light and generates two signals representing the intensity of light within two spectral wavelength bands. The first signal indicates the intensity of the return light having a wavelength within a first wavelength band. The second signal indicates the intensity of light within a second wavelength band. The processor processes the two electrical signals to determine the glucose concentration in the sample. Optical components include optical fibers or waveguides for light guidance, a dichroic filter for separating the excitation light from the return light, a slit-type septum, and a prism.

[0006] US 4,344,438 discloses a solution for measuring the concentration of a plasma component with low molecular weight in vivo. A fluorescence-based glucose sensor with a catheter-based measurement chamber is shown, wherein the detection device and the light source device are optically contacted to the chamber via an optical fiber. Here, excitation light from the light source passes through a filter to a semi-silvered mirror and is then focused onto the end of the optical fiber. In embodiments, these components can be miniaturized by using an LED for the light source and a photodiode for the photodetector, and by implanting the entire device into the body.

[0007] WO 2014 / 116597 A1 illustrates an optical system for detecting fluorescence in biological samples. The optical coupler used includes an optical fiber for contacting the phosphor, a light-emitting diode, multiple filters, and a photodiode.

[0008] EP 2 989 975 A1 discloses a fiber optic glucose sensor comprising an element having proximal and distal end regions, wherein the proximal end region is configured for coupling with an optical device including an excitation light source and a detector. The distal end can be positioned within a blood vessel and includes a hollow space and a reflective surface, wherein the hollow space includes an indicating system.

[0009] DE 43 22 734 A1 and DE 43 41 086 A1 illustrate an optical Y-coupler comprising a continuous optical waveguide with a polymer sheath and a side-entry optical waveguide with a polymer cladding. The continuous optical waveguide extends straight at the entry point, while the side-entry waveguide extends at an angle α, which is less than the critical angle for total internal reflection in the continuous optical waveguide. The continuous optical waveguide has a diameter ranging from 50 μm to 6000 μm.

[0010] US 6,553,164 illustrates a waveguide-based Y-coupler consisting of four separate sub-elements.

[0011] DE 694 14 139 T2 describes a coupling device between a multimode light source and an optical fiber using an intermediate fiber, the intermediate fiber being constructed as an optical multimode intermediate fiber. The intermediate fiber has a portion with a cross-section and a portion that gradually decreases in size. A Y-type coupler is constructed using the gradually decreasing intermediate fiber.

[0012] US 2004 / 0072358 A1 describes a glucose detection device having a sensor, a light source, and a photodetector interconnected by optical fibers. A Y-coupler, formed by splitting optical fibers into two strands, is also used. Summary of the Invention

[0013] Starting with US 2004-0072358 A1, the object of this invention is to provide an improved device for operating a biosensor. This device should both provide excitation radiation and be able to detect the measurement signal generated by the sensor with high sensitivity. Here, a small, integrable structure, secure mechanical connection to the biosensor, and high optical reliability should be achieved. Furthermore, this object is to provide an improved device for determining glucose levels, particularly blood glucose levels, which allows for mobile, quasi-continuous measurements of glucose levels.

[0014] These and other tasks are accomplished by means of an apparatus for operating a biosensor according to claim 1 or by means of an apparatus for determining glucose content according to claim 17.

[0015] The apparatus for operating a biosensor according to the invention includes an excitation light source that generates at least one excitation radiation for the biosensor. The apparatus also includes a coupling fiber, the excitation radiation being coupled into the incident surface of the coupling fiber. Furthermore, an optical Y-coupler is provided, having an excitation arm coupled to the exit surface of the coupling fiber, a detector arm coupled to an optical detector, and a sensor base coupled to the biosensor. The detector arm and the sensor base preferably have a common main beam axis. The beam axis of the excitation arm forms an angle with the main beam axis of the detector arm in the range of 5° to 70°, preferably 5° to 30°. The excitation arm has an elongated tapered shape, wherein the diameter of the excitation arm at the portion where it enters the detector arm is less than two-thirds, preferably less than half, and particularly preferably less than one-third of the diameter of the detector arm at that connection portion.

[0016] The excitation light source is preferably formed from an LED chip that emits, for example, excitation radiation at 595 nm. The excitation radiation is adapted in wavelength and optical power to the biosensor, and may also include, for example, two wavelengths, if this is desired for their respective excitation purposes. The emitting plane of the LED chip is preferably positioned at a distance from the incident plane of the coupling fiber, the distance being 0.1 to 10 times the diameter of the coupling fiber.

[0017] According to a preferred embodiment, the excitation light source is a planar scattering emitter. Emission preferably occurs from a thin layer, as does, for example, in thin-film LEDs. Therefore, it is particularly preferred that the excitation light source is formed from a thin-film LED.

[0018] The coupling fiber is preferably PMMA or sapphire fiber, having, for example, a spherical, aspherical, or planar incident surface opposite the excitation light source. The coupling fiber preferably has a diameter constant over its length, ranging from 0.1 mm to 2 mm, more preferably from 0.3 mm to 0.7 mm, and particularly preferably 0.5 mm, and a length, for example, from 5 mm to 15 mm, particularly preferably 10 mm, which is preferably 7 to 13 times the distance between the excitation light source and the incident surface of the coupling fiber. The incident surface of the coupling fiber is preferably spaced from the excitation light source by approximately 0.8 mm to 1.2 mm, particularly preferably approximately 1 mm, with the excitation beam preferably extending in the air at this distance. This distance results in only a "flat beam" being coupled into the coupling fiber, the flat beam having only a small angle relative to the central axis of the coupling fiber. The emitting area of ​​the excitation light source preferably corresponds to 10% to 60% of the cross-sectional area of ​​the coupling fiber.

[0019] An advantageous implementation is characterized in that the coupling fiber is not bent in the longitudinal direction along the axial direction, that is, its longitudinal axis extends straight. For example, the coupling fiber can be made of a rigid material for this purpose, or it can be guided in a non-bending sleeve.

[0020] According to a preferred embodiment, the exit surface of the coupling fiber is coupled to the excitation arm of an optical Y-coupler with a cutoff filter in between. This filter removes wavelengths corresponding to the fluorescence wavelength emitted by the biosensor from the excitation radiation, making it more easily detectable on the detector than the measurement signal. The cutoff filter is, for example, formed as a carrier glass with an applied filter layer. The exit surface of the coupling fiber can be adhered to the carrier glass, or it can be directly adhered to the filter layer.

[0021] A particularly preferred embodiment is characterized by a specially adapted beam guidance that allows for optimized use of the available optical power. For this purpose, the aforementioned “flat beam” is coupled into the aforementioned coupling fiber. A “flat beam” is understood to be a beam with a small angular deviation in the propagation direction. The use of such a beam also allows for the efficient use of a cutoff filter, which has removed specific wavelengths from the excitation radiation that no longer distort the measurement results. The aim is to ensure that the excitation radiation strikes the surface of the cutoff filter as perpendicularly as possible. This enables the excitation radiation to propagate in the coupling fiber with the smallest possible angular deviation from the longitudinal axis of the coupling fiber and thus strike the cutoff filter with the smallest possible angular deviation from the plane perpendicular to the cutoff filter. Preferably, the excitation radiation travels in the coupling fiber at an angle of <40° relative to the plane perpendicular to the cutoff filter or relative to the core axis of the coupling fiber, particularly preferably at an angle of <30°, and especially <25°.

[0022] An advantageous embodiment of this device is characterized in that the diameter of the excitation arm continuously decreases from its incident surface at the exit surface of the coupling fiber towards the connection point with the detector arm (so-called tapered fiber). The excitation arm thus has an elongated truncated cone shape. At the connection point, i.e., where the excitation arm, detector arm, and sensor base of the Y-coupler intersect, the diameter of the coupling arm is significantly smaller than its diameter at the incident surface. Preferably, the diameter of the excitation arm is reduced by more than half along its length. In particular, the diameter of the excitation arm at the connection point with the detector arm is in the range of 0.1 mm to 0.2 mm. The reduced portion of the excitation arm primarily serves to form an optical valve, which enables the coupling of excitation radiation into the sensor base while simultaneously minimizing undesirable outflow of fluorescence radiation returned from the biosensor to the excitation arm.

[0023] According to a preferred embodiment, a colored glass element is located between the coated carrier glass on the exit surface of the coupling fiber and the incident surface of the excitation arm, and the colored glass element supports the filtering effect of the cutoff filter. The colored glass element is constructed in a waveguide manner and may also have a tapered shape. The colored glass element is a colored optical filter glass, which is provided, for example, by Schott AG.

[0024] The Y-coupler is preferably made of plastic, especially PMMA or PC. For this purpose, 3D printing or injection molding methods are suitable, for example. The diameters of the detector arm and the sensor base are preferably the same, for example, in the range of 0.4 mm to 0.6 mm, especially 0.5 mm. The sensor base can advantageously be bent at an angle of about 90° in the longitudinal direction so that when the sensor base is implanted in the tissue substantially perpendicular to the patient's skin surface, it can be easily coupled to the biosensor at its exit surface.

[0025] A suitable implementation involves an additional colored glass element in the form of a waveguide, arranged between the detector and the exit surface of the detector arm. This colored glass element also functions as a support filter. Furthermore, it is advantageous to position the lens and filter in front of the detector to collimate the fluorescence radiation from the detector arm and filter out any remaining excitation radiation.

[0026] The detector can preferably be formed as a photodiode or a similar component. If multiple fluorescence wavelengths need to be detected, it is advantageous to combine the beam splitter with multiple photodetectors of different sensitivities.

[0027] According to the present invention, the sensor base is used not only for mechanical coupling with the sensor fiber, but also for beam steering. Preferably, a complex surface is formed in the sensor base for this purpose.

[0028] The device according to the invention for determining glucose levels, particularly in blood, includes a biosensor and a means for operating the biosensor according to one of the embodiments described herein. Attached Figure Description

[0029] Other advantages and details of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Wherein:

[0030] Figure 1 A schematic diagram of a first embodiment of a device for operating a biosensor according to the present invention is shown;

[0031] Figure 2 A schematic sketch of a second embodiment of a device for operating a biosensor is shown;

[0032] Figure 3 The optical beam path is shown for beam steering and coupled into or out of the sensor fiber in the sensor base with low optical loss. Detailed Implementation

[0033] Figure 1 A simplified side view shows a device for operating a biosensor. The biosensor is formed here as a sensor fiber 01, with a fixed, glucose-sensitive fluorescent luminescent material 02 attached to its free end. When excited by excitation radiation, the fluorescent luminescent material emits fluorescent radiation, the intensity of which depends on the glucose concentration in the medium in which the end of the biosensor is positioned. The medium can, in particular, be blood.

[0034] The device for operating the biosensor has an LED chip 03, preferably a thin-film LED, as an excitation light source. The LED chip 03 emits excitation radiation and couples it at a flat angle into a coupling fiber 04. The angle between the excitation radiation and the core of the coupling fiber is preferably <30°. For this purpose, in the illustrated embodiment, the LED 03 and the incident surface of the coupling fiber 04 are positioned approximately 1 mm apart. The incident surface of the coupling fiber can be designed as a free-form surface, spherical, aspherical, or planar surface. For example, the coupling fiber 04 has a diameter of 0.5 mm and a length of 10 mm. The exit surface of the coupling fiber 04 is secured to a supporting glass 07 using an adhesive 06. The supporting glass 07 is equipped with one or more filter layers 08 to act as a cutoff filter and filter out the wavelength of the fluorescent radiation emitted by the fluorescent luminescent material 02 from the excitation radiation. Behind the supporting glass 07 in the direction of propagation of the excitation radiation is a first colored glass element 09, which supports the effect of the cutoff filter. The first colored glass element 09 is designed in the form of a waveguide and is connected to the excitation arm 11 of the optical Y-coupler 12 on the opposite side. The excitation arm 11 and the first colored glass element 09 have cross-sections that gradually decrease in size along the radiation direction. The diameter of the excitation arm 11 at its end away from the coupling fiber 04 is therefore only, for example, 0.1 mm to 0.2 mm.

[0035] The Y-coupler 12 also includes a detector arm 13 and a sensor base 14. At the connection portion 16, the excitation arm 11 enters into a material that is also continuous from the detector arm 13 to the sensor base 14. At the connection portion 16, the detector arm 13 and the excitation arm 11 are clamped at an angle ranging from 5° to 70°, preferably from 5° to 30°, and particularly preferably about 15°. In the illustrated embodiment, the main beam axes of the detector arm 13 and the sensor base 14 extend coaxially. In a modified embodiment, the main beam axes of the detector arm and the sensor base may also extend at an angle to each other, for example, with an angle variation of 10° to 40°. The sensor base 14 is designed to be flexible or curved at its end away from the connection portion 16 so that it can be coupled to the sensor fiber 01. The detector arm 13 and the sensor base 14 have a diameter of, for example, 0.5 mm.

[0036] Excitation radiation is conducted from LED chip 03 through coupling fiber 04, excitation arm 11, and sensor base 14 to sensor fiber 01, where it excites fluorescent luminescent material 02. Fluorescent radiation emitted by the fluorescent luminescent material returns through sensor fiber 01 to sensor base 14 of Y-coupler 12, and then mostly enters detector arm 13. The end of detector arm 13 opposite to connection portion 16 is connected to a second colored glass element 17, which is formed in the form of a waveguide. An optical lens 18 is provided to collimate the fluorescent radiation emitted from the exit surface of the second colored glass element 17, followed by an additional filter 19, so that only the fluorescent radiation can pass through to reach the subsequent detector 21.

[0037] Figure 2 A modified implementation of a device for operating a biosensor is shown, which is largely based on... Figure 1 The structure is consistent with that of the filter 19. The difference is that the detector is divided into two sub-detectors 21a and 21b, which are used to detect different wavelengths of fluorescence radiation. For this purpose, a beam splitter 22 is present after the filter 19 along the beam direction, which splits the fluorescence radiation into two sub-beams according to the wavelength. The two sub-beams are then sent to their respective sub-detectors 21a and 21b. The second colored glass element 17 supports the effect of the filter 19.

[0038] Figure 3 Exemplary examples illustrate the optical beam orientation in the regions of excitation arm 11, detector arm 13, connection portion 16, and especially in sensor base 14. Sensor base 14 serves for beam steering and coupling into or out of sensor fibers, and simultaneously provides the possibility of a spacing of several hundred micrometers between the sensor base and the sensor fiber, thereby significantly simplifying positioning. As already shown from... Figure 1 and Figure 2 As can be seen, the sensor base 14 is preferably curved or arc-shaped to facilitate easy attachment to the sensor fiber 01 and to achieve beam deflection. The incident surface at the excitation arm 11 and the exit surface at the sensor base 14 thus form an angle greater than 45°, preferably approximately 90°, with each other. The connection portion 16 is particularly preferably implemented optically in a funnel shape. Figure 3 The beam trajectory in the image illustrates this, for example.

[0039] The funnel-shaped design of the connection point 16 provides a significant advantage for the optical return path, i.e., the path of fluorescence guided from the sensor fiber 01 back to the detector 21. With the beam guidance shown, optical losses can be minimized up to the point where the excitation arm enters the detector arm. Consequently, relatively small emissions (originating from the fluorescent luminescent material 02) can be evaluated particularly well on the detector. Therefore, a spacing of several hundred micrometers can be achieved between the sensor base and the sensor fiber, which is a significant advantage for practically relevant constructions.

[0040] Lens 23 is preferably constructed on the side of sensor base 14 facing sensor fiber 01, and is preferably integrated into the material of sensor base. Lens 23 is located behind the toric surface in the direction of excitation radiation so as to focus the excitation radiation onto the input end face of sensor fiber 01. The lens can be formed as a spherical or aspherical lens, and is anti-reflective if necessary.

[0041] Particularly preferably, the numerical aperture obtained after the lens 23 at the sensor base 14 in the direction toward the sensor fiber 01 is adjusted so that it substantially corresponds to the numerical aperture of the sensor fiber.

[0042] According to a preferred embodiment, the excitation arm 11 is widened in diameter in the region of the connection portion 16, such as... Figure 3 The beam trajectory is as shown. This widening is preferably achieved by a linear increase in diameter toward the sensor base 14, or alternatively a non-linear increase. The widened envelope of the cone generated in the longitudinal section can therefore be arbitrarily shaped.

[0043] In the curved region of the sensor base, the beam is preferably deflected on the complex surface 24, which can be mathematically described as follows:

[0044]

[0045] in,

[0046] - The first radius of the complex surface relates to the X-axis (the radius about the axis along the X direction).

[0047] (R_um_X; C = 1 / R_um_X);

[0048] -KK = Conical constant;

[0049] - The Y coordinate is substituted into the formula as y, and the Z coordinate is obtained for the following case: the complex surface has its origin at the points Y=0 and Z=0, and it has not rotated 45° counterclockwise.

[0050] - The second radius of the complex surface relates to the Y-axis (the radius about the axis along the Y direction), for the case where the complex surface is not rotated 45° counterclockwise.

[0051] The reflection preferably occurs as total internal reflection on the tortuous surface. Alternatively, an additional reflective layer can be applied to this region. This is suitable if the refractive index of the material in the sensor base is too low, in which case total internal reflection is impossible. In this case, an additional reflective layer can be applied to the tortuous surface.

[0052] This design ensures that the excitation radiation extends from the excitation arm 11 through the widened portion and tortuous surface 24 in the region of the connection portion 16 to the lens 23 within the material of the excitation arm. Transition to air or gas occurs only at the lens 23, and subsequently into the sensor fiber 01.

[0053] List of reference numerals

[0054] 01 Sensor Fiber

[0055] 02 Fluorescent materials

[0056] 03 LED Chips / LED

[0057] 04 Coupling Fiber

[0058] 05 --

[0059] 06 Adhesives

[0060] 07 Load-bearing glass

[0061] 08 Filtering Layer

[0062] 09 First Colored Glass Components

[0063] 10 --

[0064] 11 Excitation Arm

[0065] 12 Y-couplers

[0066] 13 detector arms

[0067] 14 Sensor Base

[0068] 15 --

[0069] 16 Connection parts

[0070] 17 Second colored glass piece

[0071] 18 lenses

[0072] 19 Filters

[0073] 20 --

[0074] 21 detectors

[0075] 22 beam splitters

[0076] 23. Aspherical lenses

[0077] 24 Complex Surface

Claims

1. An apparatus for operating a biosensor that emits radiation, the apparatus comprising: - An excitation light source that generates at least one excitation radiation for a biosensor; - Coupled fiber, the excitation radiation is coupled into the incident surface of the coupled fiber; - Optical detector; and - An optical Y-coupler having an excitation arm connected to the exit surface of a coupling fiber, a detector arm connected to an optical detector, and a sensor base that can be connected to a biosensor. The excitation arm has a tapered shape, and the beam axis of the excitation arm and the main beam axis of the detector arm form an angle between 5° and 70° at the connection point between the detector arm and the excitation arm. The diameter of the excitation arm at the connection point with the detector arm is less than two-thirds of the diameter of the detector arm, and the excitation arm has a cross-section that gradually decreases in the radiation direction. The incident surface of the excitation arm is optically coupled to the exit surface of the coupling fiber. The diameter of the excitation arm continuously decreases from its incident surface toward the connection point with the detector arm. The excitation arm thus has an elongated truncated cone shape, and the coupling fiber is constructed with a straight longitudinal axis.

2. The apparatus of claim 1, wherein, The diameter of the excitation arm at the connection point is less than half the diameter at its incident surface.

3. The apparatus of claim 1 or 2, wherein, The detector arm and the sensor base share a common main beam axis.

4. The apparatus according to claim 1 or 2, characterized in that, The excitation light source is an LED chip, and the emitting plane of the LED chip is positioned at a distance from the incident surface of the coupling fiber, the distance being 0.1 to 10 times the diameter of the coupling fiber.

5. The apparatus according to claim 4, characterized in that, The coupling fiber has a length that is 7 to 13 times the distance between the excitation light source and the incident surface of the coupling fiber.

6. The apparatus according to claim 5, characterized in that, The length is in the range of 7mm to 13mm.

7. The apparatus according to claim 4, characterized in that, The incident surface of the coupling fiber is constructed as a flat surface, a spherical surface, an aspherical surface, or a free-form surface.

8. The apparatus according to claim 1 or 2, characterized in that, A cutoff filter is arranged between the exit surface of the coupling fiber and the incident surface of the excitation arm, the cutoff filter filtering out wavelengths of radiation that can be emitted by the biosensor from the excitation radiation.

9. The apparatus according to claim 8, characterized in that, The cutoff filter is made of a carrier glass having an optical filtering layer applied thereon.

10. The apparatus according to claim 9, characterized in that, The exit surface of the coupling fiber is attached to the filter layer.

11. The apparatus according to claim 1 or 2, characterized in that, A lens is arranged between the exit surface of the detector arm and the detector to collimate the radiation emitted by the biosensor, wherein an optical filter is arranged between the lens and the detector to block the incident fraction of the excitation radiation.

12. The apparatus according to claim 1 or 2, characterized in that, A waveguide-shaped colored glass element is arranged on the exit end of the detector arm.

13. The apparatus according to claim 1 or 2, characterized in that, The sensor base includes a curved section in which the beam is deflected at an angle greater than 45°.

14. The apparatus according to claim 13, characterized in that, In the curved section, the beam is deflected at an angle of 90°.

15. The apparatus according to claim 13, characterized in that, A complex surface is constructed in the sensor base to deflect the beam.

16. The apparatus according to claim 1 or 2, characterized in that, The device is also configured to determine glucose levels and includes a biosensor that can be implanted in tissue and emits radiation upon excitation.

17. The apparatus according to claim 16, characterized in that, The device is also configured to determine the glucose content in the blood.

18. The apparatus according to claim 16, characterized in that, The biosensor is formed as an optical fiber, the optical fiber having a glucose-sensitive fluorescent luminescent material on its exit surface, which emits fluorescent radiation with a fluorescent wavelength when excited by excitation radiation.

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