EP1974202A1 - Faseroptisches fluoreszenzsensorsystem - Google Patents
Faseroptisches fluoreszenzsensorsystemInfo
- Publication number
- EP1974202A1 EP1974202A1 EP06841049A EP06841049A EP1974202A1 EP 1974202 A1 EP1974202 A1 EP 1974202A1 EP 06841049 A EP06841049 A EP 06841049A EP 06841049 A EP06841049 A EP 06841049A EP 1974202 A1 EP1974202 A1 EP 1974202A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fluorescence
- sensor system
- light
- fluorescence sensor
- fiber optic
- 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- Withdrawn
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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/645—Specially adapted constructive features of fluorimeters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0071—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence by measuring fluorescence emission
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
- A61B5/0084—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
-
- 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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
-
- 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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N2021/6417—Spectrofluorimetric devices
- G01N2021/6419—Excitation at two or more wavelengths
-
- 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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/645—Specially adapted constructive features of fluorimeters
- G01N2021/6484—Optical fibres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/062—LED's
- G01N2201/0625—Modulated LED
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/069—Supply of sources
- G01N2201/0691—Modulated (not pulsed supply)
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/069—Supply of sources
- G01N2201/0696—Pulsed
Definitions
- the invention relates to a fiber optic
- Fluorescence sensor system for fluorescence examination of a particular biological sample containing fluorophores, uses of the fiber optic fluorescence sensor system and a method for the quantitative determination of fluorophores in the sample.
- Fluorescence spectroscopy is an effective method for studying the biochemical and morphological properties of tissue and other biological samples.
- fluorescence spectroscopy is fast, non-invasive and allows quantitative measurements, so that e.g. For example, tissue properties such as metabolism rates, vascularity, intravascular oxygen content, and changes in tissue morphology can be examined.
- tissue properties such as metabolism rates, vascularity, intravascular oxygen content, and changes in tissue morphology can be examined.
- tissue properties such as metabolism rates, vascularity, intravascular oxygen content, and changes in tissue morphology can be examined.
- tissue properties such as metabolism rates, vascularity, intravascular oxygen content, and changes in tissue morphology can be examined.
- process control in fermentations to name just a few examples.
- fluorophores are irradiated in a sample, in particular with short-wave light, in order to excite their fluorescence.
- the excitation maxima are typically in the UV / blue Range between 200 and 500 nm and the maxima of the fluorescence emission in the range between 280 and 700 nm.
- Endogenous fluorophores are e.g. Amino acids, such as tryptophan and tyrosine, structural proteins, such as collagen or
- Elastin enzymes and coenzymes, such as FAD, flavins, NADH and NADPH, vitamins, especially vitamins A, K and D, vitamin B6 ingredients, lipids and porphyrins.
- the fiber-optic fluorescence excitation was carried out either with gas discharge lamps, such as xenon or mercury vapor lamps or short-wave lasers.
- the excitation light is coupled into the sample via one or more optical fibers and emitted by the fluorophores in the sample
- Fluorescence light coupled via one or more optical fibers to be subsequently detected with a spectrograph Fluorescence light coupled via one or more optical fibers to be subsequently detected with a spectrograph.
- Mercury vapor lamps is that these are difficult to use and prone to failure. Furthermore, they produce a broad emission spectrum, so typically optical filters are used to filter the light emitted by the lamps, which in turn causes thermal problems. Furthermore, these lamps pose safety risks due to the high voltage used and with respect to an explosion hazard.
- gas discharge lamps are laser, such. As nitrogen laser or laser-pumped dye laser used. However, these are also costly and difficult to use. Furthermore, there are strict safety requirements for the use of such lasers, especially in the medical field.
- a fluorometer with a pulsed LED and a photodetector is also known, which distinguishes between weak fluorescence signals and superimposed signals.
- this fluorometer is designed to observe light-induced chlorophyll fluorescence changes. A spectrally differentiated measurement is not provided.
- a disadvantage is therefore that the fluorometer is only suitable for studies in which a prominent Flurozenzsignal is generated. Furthermore, this fluorometer does not appear to be suitable for medical application or online process tracking and requires complicated signal processing.
- the invention is therefore based on the object to provide a fiber optic fluorescence sensor system with good pay-to-noise ratio, which can be operated under ambient conditions in ambient light and at the same time is suitable for the investigation of samples with little or superimposed by background fluorescence spectra ,
- Yet another object of the invention is to provide a fiber optic fluorescence sensor system which overcomes the disadvantages of known systems, such as e.g. As described in the introduction, avoids or at least reduces.
- the object of the invention is achieved in a surprisingly simple way already by the subject matter of the independent claims. Advantageous developments of the invention are defined in the subclaims.
- a fiber optic According to the invention, a fiber optic
- Fluorescence sensor system for continuous in situ or in-line fluorescence examination of a particular biological, containing fluorophores sample provided. Experts also speak of in-situ fluorometry.
- Excitation of fluorescence emitted in the sample with a fiber optic probe, via the probe tip, the excitation light coupled into the sample and the emitted from the fluorophores in the sample - secondary - fluorescence light is coupled out with a fiber optic probe, via the probe tip, the excitation light coupled into the sample and the emitted from the fluorophores in the sample - secondary - fluorescence light is coupled out with a fiber optic probe, via the probe tip, the excitation light coupled into the sample and the emitted from the fluorophores in the sample - secondary - fluorescence light is coupled out with a
- the light source emits light within a narrow interval in the spectral range between 200 and 700 nm.
- the excitation light emitted by the light source and emerging from the probe into the sample is particularly preferably ultraviolet to blue light, which is why UV / VIS fluorometry is also used. It is particularly preferable to use UV light or blue light having a wavelength less than or equal to 470 nm, in particular in the range between 350 nm and 380 nm.
- the detector device comprises at least one detector, in particular an opto-electrical converter for detecting the fluorescent light.
- the optical waveguide comprises at least one optical receiving fiber in the form of a Glass fiber, possibly made of quartz glass.
- the detector is connected to the probe tip by means of the receiving fiber in order to forward the fluorescent light from the probe tip via the receiving fiber to the detector.
- the fluorescence sensor thus comprises a fiber optic probe, e.g. a dip probe for fermentation measurements or a fiber optic endoscope for biomedical applications.
- a fiber optic probe e.g. a dip probe for fermentation measurements or a fiber optic endoscope for biomedical applications.
- Such fiberglass sensor systems are advantageously of compact design.
- Probe tip or the sensor head can be built with a diameter of less than or equal to 5 mm, in particular in the medical field of less than or equal to 1 mm.
- the respective glass fibers have an outer diameter of typically 0.3 mm.
- the detector produces a continuous electrical output whose magnitude is a measure of the intensity of the fluorescent light to continuously and quantitatively measure the fluorescent light.
- the magnitude of the electrical output signal is a function of the intensity of the measured fluorescent light.
- the light source comprises at least one light-emitting diode.
- the light source consists of an incoherent light-emitting diode, a so-called LED, a laser diode or a diode-pumped laser for generating the excitation light.
- the semiconductor-based light sources are also distinguished from a gas discharge lamp by a very low power consumption and a small design, whereby the thermal load of the components is reduced and a miniaturization of the fluorescence sensor is achieved. Furthermore, they are inexpensive and virtually maintenance free.
- the narrowband spectral range of the semiconductor-based light sources e.g. incoherent LEDs, laser diodes or diode-pumped lasers of less than ⁇ 20 nm provide tailor-made fluorescence excitation. It can therefore be dispensed in the transmitting branch preferably on optical filters or monochromators, d. H. be excited with the unfiltered primary light, and yet a targeted fluorescence excitation of certain fluorophores can be achieved. If, nevertheless, a further narrowing of the excitation spectrum is desired, an optical filter can additionally be installed in the transmitting fiber, but its thermal load compared to a gas discharge lamp is considerably reduced.
- Excitation light varies with time, in particular with a modulation frequency f preferably amplitude-modulated time-continuous.
- the input voltage of the light source is changed over time, in particular modulated, so the excitation light is emitted amplitude-modulated by the light source at the modulation frequency.
- the temporal change is chosen slowly compared to the decay behavior of the fluorescence, in particular, the modulation frequency is chosen to be small compared to the inverse decay time of the fluorescent light, the latter is typically a few nanoseconds, ie in particular less than 10 MHz.
- the decay behavior of the fluorescent light does not or not significantly affect the time course of the fluorescent light.
- a so-called steady-state measurement is carried out in which the secondary fluorescent light emitted by the sample is amplitude-modulated continuously with the modulation frequency f. Preferably, it is excited with a sinusoidal, rectangular or similar modulation function.
- time scans in particular real-time measurements can be performed.
- the light source can also be operated pulsed.
- a constant light suppression is performed, for example, to filter out ambient light.
- the fluorescence sensor system has two or a plurality of reception branches, which are designed for the temporal and spectrally resolved quantitative detection of the fluorescent light. That is, each reception branch measures a permanently defined spectral range of the fluorescent light, the spectral ranges of the different reception branches preferably not overlapping. Thus, the fluorescent light in the respective spectral range is selectively and quantitatively measured.
- each reception branch comprises a detector which in each case generates an output signal which is a measure of the intensity of the fluorescent light in the associated spectral range.
- each of the detectors is associated with an electronic means for light suppression, which is adapted in each case to the temporal variation of the light emission, so that the first receiving branch a gleichunterunteronnes quantitative first measurement signal of the intensity of the fluorescent light in the first spectral range and the second receiving branch a gleichunteruntersistedes quantitative second measurement signal generates the intensity of the fluorescent light in the second spectral range and thus a gleichunteruntercontactede quantitative spectrally resolved evaluation of the fluorescent light is possible.
- the spectral ranges are preferably predefined in front of the detectors by means of optical filters of different wavelength intervals. For certain applications, however, it may also be sufficient to use detectors with spectrally limited detection efficiency.
- the width of the spectral regions is preferably less than ⁇ 50 nm, more preferably between ⁇ 2 nm and ⁇ 20 nm.
- the spectral resolution of the background extraction system is used.
- the first spectral range is selected such that the expected fluorescence maximum of a first fluorophore to be detected in the sample is covered.
- Spectral range is chosen to cover an expected background region of the fluorescence spectrum.
- the system comprises a differential amplifier in which the first and second measurement signal are fed, so that only the difference between the two signals is amplified or the difference between the two channels is evaluated by means of a microcontroller.
- a uniformly suppressed and spectrally sublimated measurement signal is obtained, which is a measure of the intensity of the fluorescent light of the fluorophore to be detected.
- the output signal of the detectors in the respective reception branch is electronically processed in accordance with the type and period of the temporal change of the excitation light, in order to achieve a simultaneous light suppression in each reception branch.
- the frequency range of the filter in particular bandpass filter, is adapted to the modulation frequency, so that essentially only modulated signal components are passed through and direct light or direct signal components are filtered out.
- the bandpass filters thus have a center frequency approximately equal to the modulation frequency f.
- the modulation frequency is preferably between 200 Hz and 10 MHz, more preferably between 1 kHz and 1 MHz, so that, in particular, also mains-frequency ambient light is filtered out electronically. This ensures the high sensitivity required in particular for intrinsic fluorescence measurement, making the sensor suitable for cell research. It has been found that the light intensity of light emitting diodes with high light output is then sufficient,. to perform fluorescence measurements on biological materials (cell suspensions, tissues, solutions, etc.). Since, depending on the metabolism, the fluorophore
- composition in biological materials or cells changes, it is possible with the help of this fluorescence sensor and the evaluation process to draw conclusions about the cell state.
- the system is therefore particularly suitable for on-line bioprocess tracking or monitoring, e.g. from
- Fermentation processes for medical diagnosis, for cancer diagnosis and for bioanalytics.
- With the invention is a simple, inexpensive and user-friendly system for fluorescence measurements liquid and solid samples without the need for sample preparation.
- Modulation frequency f used so that the LED is operated with an AC voltage, in particular sine or square-wave AC voltage with the modulation frequency f.
- the electronic noise is also reduced and the electrical output of the detectors, downstream of the electronic filters, can be amplified higher with an amplifier.
- a rectifier is provided for rectifying the filtered detector signals.
- an override indicator can be connected to the electronic filter and / or the rectifier in order to detect a possible overdrive.
- the system has an evaluation device for recording the detector signal or signals over a macroscopic time period and means for the time-resolved representation of the fluorescence intensity over the time period around a time-continuous measurement, e.g. to enable process tracking.
- the light emitting diode may be located remote from the probe tip.
- the optical fiber at least one optical transmission fiber, which connects the light-emitting diode to the probe tip, in order to forward the excitation light from the light-emitting diode via the transmitting fiber to the probe tip for coupling into the sample, in addition to the receiving fiber.
- the light-emitting diode may even be integrated into the probe tip due to its small size and directly irradiate the sample, so that it is possible to dispense with the transmitting fiber.
- detectors photomultiplier or photosemiconductor are used according to a simple embodiment. These are preferably preceded by an optical filter in each case in order to detect a specific wavelength of the fluorescent light. In order to record a complete fluorescence spectrum, but under certain circumstances, a spectrometer with a CCD chip and a CCD chip upstream polychromator can be used.
- the light source comprises a plurality of light emitting diodes having different excitation light wavelengths.
- a first excitation light wavelength is selected such that it excites substantially only a first fluorophore and a second excitation light wavelength such that the first and a second fluorophore are excited.
- the subtraction of the measurement signals can be further improved and thus the signals of the different fluorophores can be prepared even better.
- the plurality of light-emitting diodes have different emission wavelengths, in each case in the spectral range between 200 nm and 700 nm, preferably between 250 nm and 500 nm, more preferably between 350 nm and 450 nm.
- the light-emitting diodes have the advantage that they have a relatively narrow emission spectrum with a half-width in the range of about ⁇ 5 nm to ⁇ 20 nm, so that it may be possible to dispense with an optical filter in the transmitting branch wherein at least some of the wavelengths of the different light emitting diodes are selected from the following group of wavelengths: 350 nm, 370 nm, 410 nm, 420 nm, 460 nm.
- the multi-wavelength fluorescence excitation is carried out with the different wavelengths simultaneously or with a time delay. In the latter case, the fluorescence signals or fluorescence spectra with different excitation light wavelengths can be subtracted even better from each other to select certain fluorophores.
- the fluorescence sensor comprises a plurality of parallel receiving branches, preferably each with an optical receiving fiber, in each case one to the associated
- Reception fiber connected detector in particular a semiconductor detector or a photodiode. Since these have a relatively broad detection spectrum, each detector is preferably an optical filter with different Wavelength ranges upstream, so that each detector receives fluorescent light of a predetermined wavelength interval and a simultaneous quantitative detection of fluorescent light of different wavelength intervals and / or a background subtraction is possible. In other words, wavelength-discrete detection of the fluorescent light is performed within predetermined spaced apart intervals or spectral ranges.
- the evaluation device can then optionally assign them to different fluorophores. It has proven expedient to use optical filters with a bandwidth of in each case less than ⁇ 50 nm, preferably less than ⁇ 20 nm, particularly preferably less than ⁇ 10 nm, in the reception branches.
- the invention allows both a multiple fluorescence excitation and a multiple fluorescence detection or a multiple fluorescence evaluation.
- a multi-component analysis involves concentration determination of various biofluorophores (e.g., NADH, NADPH, flavins (FAD, FMN, riboflavin), porphyrins, pyridoxins, collagen, elastin, lipo-pigments, fluorescent amino acids such as
- the fluorescence emission spectra of the fluorophores in the respective matrices should be known, e.g. is achieved by targeted accumulation and depletion of individual biofluorophore in the respective biological matrix.
- the simultaneous quantitative detection of the different biofluorophores is thus according to the invention not only with a wavelength-selective spectrometer, but also with the multiple parallel semiconductor detectors in conjunction with the respective optical filters. This is significantly less expensive, more compact and less energy consuming than a spectrometer. This makes it possible, inter alia, for the first time to operate the system with a battery which supplies at least the light source and / or the detectors.
- Fluorophores known in the respective biological Matrizen or environments it is possible with various multivariate evaluation, to calculate back from the measured fluorescence spectrum of the sample on the concentrations of the individual fluorophores.
- a fluorescence sensor system is provided with a miniaturized fiber optic fluorescence sensor which allows the fluorescence of biological materials to be measured continuously and quantitatively.
- Fig. 1 is a schematic representation of a single-channel fiber optic fluorescence sensor system with an LED directly on the probe tip
- Fig. 2 is a schematic representation of a single-channel fiber optic fluorescence sensor system with LED light coupling via an optical fiber
- Fig. 3 is a measured yeast culture fluorescence spectrum (after 10 hours of fermentation) from the
- FIG. 4a shows the time course of NAD (P) H, flavin (FAD, FMN) and porphyrins
- Fig. 4b shows the time course of
- Fig. 5 is a schematic representation of the fiber optic
- Fig. 6 is a representation like Fig. 5, but in addition with m LEDs and m transmitting fibers for excitation with
- Fig. 7 is a block diagram of the structure for modulated operation of the LED and electronic filtering for a transmitting and receiving branch
- Fig. 8 is a block diagram of the structure for the modulated operation with square wave signals and integration for a transmitting and receiving branch
- Fig. 9 fluorescence image of a Hand with actinic keratosis after application of a Metvix® cream
- Fig. 10 fluorescence spectra showing the increase of
- FIG. 13 shows a block diagram of the structure for the modulated operation of a fluorescence sensor system with four receiving branches and microcontroller
- FIG. 14 is a block diagram of the structure for the modulated operation of a
- Fluorescence sensor system with two receiving branches and differential amplifier.
- a fiber optic fluorescence sensor system comprising a fluorescence sensor 1 with a dip probe 12 and a detector 14 is shown.
- the detector 14 comprises a photodiode Dl.
- a UV LED LEDl emits UV primary light to excite the fluorescence, which in turn causes the emission of secondary fluorescent light 20 from the sample 24.
- the fluorescent light 20 is emitted from the fluorophores in the sample 24.
- the incoherent LED LED is disposed within the immersion probe 12 directly to the probe tip 26. This can be done on one
- the optical waveguide 13 of the immersion probe 12 accordingly comprises only one receiving fiber El which forwards the fluorescent light 20 to the detector 14.
- the fluorescent light 20 emitted by the sample 24 or the fluorophores in the cells in all directions in space is shifted towards larger wavelengths than the primary or the excitation light.
- a fraction of this fluorescence emission finally passes via the probe tip 26 and the receiving fiber El into the detector device 14.
- the detector device 14 is further connected to a computing device 28 for data acquisition, evaluation, storage and display.
- FIG. 2 shows a fluorescence sensor system in which the excitation light-emitting light-emitting diode LED1 is arranged externally to the immersion probe 12 remote from the probe tip 26.
- the excitation light of the LED LED is guided to the sample 24 via a transmitting fiber S1 in the optical waveguide 13, which runs parallel to the receiving fiber E1 within the immersion probe 12 as far as the sensor tip 26.
- the optical fiber probe 12 or its probe tip 26 according to FIG. 2 comes without electrical supply. Therefore, the probe 12 can be temperature stable to about 200 0 C or more designed. This is particularly advantageous for applications that come in contact with biologically active material, because the probe tip or the sensor head 26 can be heated and therefore autoclavable and sterilized. Germs are thereby killed and the sensor 1 can be used repeatedly without further transporting contaminations and infections from site to site.
- Such fiber optic sensors 1 can be realized in different designs.
- the probe tip 26 can be made to be intravenously applicable. It is also possible to work with curved capillaries that can be used at measuring sites such as the back of the eye.
- the probe 12 can have a large length, for example, to be used in large fermenters. Such probes 12 can dip up to 10 meters or more into biological reactors, and yet on the whole Length temperatures up to 200 0 C endure.
- Another important area of application for the sensors is explosive environments. Here most of the electrical devices can not be used, but with incoherent light operated purely optical probes. According to the Ex protection guideline, care must be taken that a light load of 5 mW / mm 2 is not exceeded.
- the fluorescence sensor 1 has a broad spectrum of applications in bioanalytics, process monitoring, biomedical fluorescence spectroscopy, medical diagnostics, in particular cancer diagnostics and in drug discovery.
- a major advantage of fluorescence spectroscopy is that with this
- Biochemical processes in cells can be followed non-invasively and quantitatively.
- various chemical substances involved in the metabolism such as NAD (P) H, flavins, porphyrins, etc., which can be excited to fluoresce upon irradiation with UV light or blue light. It turns out that each of these biofluorophores emits a characteristic fluorescent light with a corresponding spectral distribution. If there is a change in the intracellular metabolism as a result of a disease such as cancer, then this has an influence on the
- Tumor diagnosis eg, by determining the ratio of NAD (P) H to porphyrin fluorescence or the ratio of flavin to porphyrin fluorescence
- P NAD
- FIG. 3 illustrates a multi-component analysis using the example of a fluorescence spectrum recorded online during a yeast fermentation in a bioreactor.
- the total fluorescence spectrum recorded after a fermentation period of ten hours consists essentially of the two components NAD (P) H with an emission maximum at about 470 nm and flavins in one
- Living cells such as microorganisms (yeast, E. coli, etc.) contain biofluorophores such as NAD (P) H, flavins, porphyrins, etc., whose time course allows conclusions to be drawn on the metabolic status of the cell and the course of the process.
- biofluorophores such as NAD (P) H, flavins, porphyrins, etc.
- each reception branch Z1 to Zn in the fluorescence sensor covers a spectral range of approximately 475 nm ⁇ 10 nm (NAD (P) H), and the second reception branch Z2 covers a spectral range of approximately
- the fluorescence intensities in the individual reception branches or channels Z1 to Z4 are measured and "offset" against each other so that concentration curves for the individual biofluorophores (NAD (P) H, flavins, porphyrins) finally result are shown in Fig. 4a.
- the porphyrin content (curve 44) can be determined from the remaining intensity at about 630 nm. In this type of evaluation, it is therefore sufficient to measure the fluorescence intensities at specific wavelengths (in the example: at 470 nm, 530 nm, 630 nm) in order to determine the corresponding fluorophore concentrations.
- Fig. 5 shows a fluorescence sensor system 1 having a plurality of reception branches, each reception branch Z1 to Zn having a receiving optical fiber El to En.
- the fluorescent light emitted by the sample is coupled into these receiving fibers El to En.
- At the end of each receiving fiber El to En there is an optical spectral filter Fl to Fn, which transmits only light of a specific wavelength or a specific wavelength range.
- the photo-detectors D1 to Dn which are e.g. Photodiodes or photomultiplier (photomultiplier) acts.
- Fluorescence intensities at the wavelengths specified by the filters F1 to Fn occur at the same time, so that the fluorophore composition of the sample is correctly determined even in rapid biological processes.
- Fig. 5 When the embodiment shown in Fig. 5 is e.g. With four reception branches Z1 to Z4 with optical interference or bandpass filters at 470 nm, 530 nm, 630 nm and 700 nm, the selective quantitative and continuous measurement and subtraction, including offset correction, explained with reference to FIGS. 3 to 4b can be performed with the sensor , It will be apparent to those skilled in the art that also optical edge filters, e.g. Longpass and / or shortpass filters can be used. These can in particular satisfy in combination with a limited spectral reception range of the photodiodes.
- optical edge filters e.g. Longpass and / or shortpass filters
- FIG. 6 shows a further embodiment of the invention with a plurality of emitting light-emitting diodes LED1 to LEDm, which have different emission wavelengths for fluorescence excitation and respectively associated transmitting fibers S1 to Sm. This embodiment is particularly advantageous when the
- Multi-component analysis is made difficult by the fact that the fluorophores have strongly overlapping fluorescence bands in the sample to be analyzed.
- the LEDl specifically only the fluorophore with the long-wave fluorescence excitation spectrum can be excited and determined.
- the concentration can now be determined since the proportion of the first-mentioned fluorophore can be subtracted from the measured fluorescence intensity.
- several or all light-emitting diodes LED1 to LEDm can be coupled into a transmitting fiber.
- the LEDs I to LEDm can also be arranged in the probe tip if the probe 12 does not have to be optimized for miniaturization.
- the LED LEDl is operated with a sinusoidal AC voltage.
- the LED is operated by an oscillator 62 with a predetermined frequency f, which is fed by a common voltage supply 64.
- the fluorescent light 20 excited thereby is likewise sinusoidally modulated and detected by the detector 14 with the photodiode D1.
- the output signal of the photodiode D 1 is largely proportional to the received fluorescence light intensity, so that the detector signal is also modulated at the frequency f.
- the bandpass filter 66 is connected to the detector Dl and adjusted so that it passes only the alternating component of the detector signal with the frequency f. Thus signals generated by room light or constant light are suppressed.
- the suppression can be effected, for example, by bandpass filtering with a slope of preferably 20 to 60 dB / decade.
- the modulation frequency f is preferably chosen between 1 kHz and 1 MHz, more preferably between 2 kHz and 100 kHz.
- An amplifier 68 is connected to the bandpass filter 66 to amplify the filtered signal.
- a rectifier 70 is connected to the amplifier 68 to rectify the amplified signal. The rectified signal is sent to the evaluation and display device 28 for further
- An overdrive indicator 72 is connected to the output of the detector 14 and the output of the amplifier 68.
- the power supply 64 feeds all components.
- Fluorescence light 20 the actual measurement signal leads, can perform. Especially in medical applications, e.g. In endoscopy, this makes it possible for the physician to visually inspect the tissue to be examined in parallel with the fluorescence measurements.
- Fig. 8 shows a block diagram for a modulated operation of the system 1 with square wave signals. That the modulation is realized in the form of a clocking.
- Integrator circuit used.
- the integrator circuit combines very low noise with the possibility of high gain for the incoming signals.
- the LED is driven with a clocked voltage signal in the form of a periodic square wave signal of a period of, for example, between 5 ms and 2 s (on-time) and then switched dark for a further period of time (off-time).
- the operating voltage of the LED LEDl is generated by a voltage supply 80 which is clocked by a clock generator 82 with the clock signal Tl becomes.
- the excitation light emitting LED LEDl is supplied clocked and emits pulsed excitation light.
- the output signal of the detector is measured coincident with the voltage signal, more precisely integrated during the duration of the on-time of the voltage signal by means of the integrator 84, the integrator 84 being connected to the light-emitting diode LED1.
- the useful signal is then determined as the difference between the integrated output signal during the on-time and the off-time of the LED.
- the integrator 84 embodies a means for
- the integrator 84 is also connected to the clock generator 82 and is supplied by the latter with the clock signal T2, such that the light-emitting diode D1 and the integrator 84 are controlled with the same clock.
- the output signal of the integrator 84 is amplified by means of an amplifier 86 and digitized by means of an A / D converter 88, in order subsequently to be further processed digitally by the evaluation and display device 28.
- a temporally varied illumination is a pulsed mode of operation of the LED.
- This has the advantage that you get a high signal at the time of the pulse.
- the combination with a fast detector makes sense, e.g. a charge amplifier in which the first stage amplifies low and a second amplification stage high. While it is true that the light intensity of light emitting diodes is not proportional to the supply current at high and short term loads, light emitting diodes, e.g. for one
- Continuous operation with 20 mA are designed, with up to 10 A short-term load and then reach a multiple of short-term light emission.
- the purging time is preferably chosen to be longer than 100 ns in order to avoid interference with the decay behavior of the fluorescence, so that a "quasi-continuous" suggestion can be spoken.
- the marker can be administered intravenously, orally or externally, e.g. be applied in the form of an ointment.
- the marker is a precursor, eg 5-aminolevulinic acid (5-ALA) or an ester of 5-ALA Typical concentrations for use are 20 to 40 mg per kg body weight, in the animal model also up to 150 mg / After a few hours, protoporphyrin IX (precursor of heme) forms in the cells, whereby - depending on the precursor substance - a higher, ie specific PPIX accumulation in tumor cells is observed PPIX has a high light absorption in the blue spectral range at about 405 When PPIX is irradiated with blue light, some of the absorbed photons are converted to fluorescence light (emission maximum at 635 nm), which results in a visual contrast of the tumorous tissue to the surrounding healthy tissue.
- 5-ALA 5-aminolevulinic acid
- Typical concentrations for use are 20 to 40 mg
- an aminolevulinic acid-containing ointment was externally applied to a back of the hand with actinic keratosis as a marker drug.
- actinic keratosis is e.g. available as Metvix® cream.
- the photosensitizer protoporphyrin IX selectively accumulates in tumorous tissue.
- the spectra were measured immediately after application (0 hours) and after 1, 2 and 3 hours.
- the superimposed endogenous fluorescence (collagen, NAD (P) H, flavins etc.) is measured at two wavelengths in the spectral ranges of the reference channels 1 and 2 and, if necessary. after mathematical factor calculation, subtracted from the fluorescence in the spectral range to be measured at 635 nm (measuring channel).
- the three non-overlapping spectral regions have a width of about ⁇ 10 nm.
- a spectral range to be measured is used for the fluorophore to be detected (in this case protoporphyrin IX) and two background spectral ranges (so-called reference channels 1 and 2).
- PPIX In light absorption, PPIX is first excited from S 0 to Si. By "intersystem crossing", a small part of the PPIX molecules goes into the triplet state Ti. Since molecular oxygen O 2 has a triplet ground state, the excitation energy of the PPIX can now be transferred to O 2 in the Ti state
- an ointment containing aminolaevulinic acid was applied to a back of the hand with actinic keratosis, such as the back of the hand shown in FIG.
- actinic keratosis such as the back of the hand shown in FIG.
- the protoporphyrin concentration in the dysplastic tissue reaches its maximum (see Fig. 10), so that it is possible to start the therapeutic light irradiation (for example by means of the Aktilite® light source) for several minutes.
- the photosensitizer PPIX degrades over time via the intermediate product photoprotoporphyrin (PPP) (emission maximum at about 675 nm).
- PPP intermediate product photoprotoporphyrin
- Fig. 11 shows a fluorescence spectrum before and during the PDT. There is a decrease in protoporphyrin IX fluorescence and the formation of the degradation product photo-protoporhyrin during PDT compared to prior to PDT.
- the background from the reference spectral regions is subtracted from the fluorescence intensities to be detected in the spectral regions around 635 nm and 675 nm (here protoporphyrin IX and photo-protoporphyrin, measuring channels 1 and 2) by means of the circuit according to FIG.
- four reception branches Z1 to Z4 (measuring channels 1 and 2, reference 1 and 2) are used.
- FIG. 13 shows a block diagram with four reception branches Z 1 to Z 4 for carrying out the measurement explained with reference to FIG. 11.
- the four reception branches Z1 to Z4 are each designed in accordance with FIG. 7, but each detector D1 to D4 is preceded by an optical filter F1 to F4.
- the evaluation including background subtraction takes place in a common evaluation device 28 in the form of a microcontroller.
- FIG. 14 shows a block diagram of an alternative embodiment with two reception branches Z1 and Z2 according to FIG. 7, wherein the reception branch Z1 processes a background signal and the reception branch Z2 processes a measurement signal.
- An adjustment amplifier or attenuator 28a for example, which can be set by means of a potentiometer, serves to equalize different sensitivities of the two reception branches Z1 and Z2. Subsequently, the two signals in one Differential amplifier 28b fed and thus amplifies the difference signal between the measurement and background signal to cause by means of the evaluation device 28, a subtraction of the background signal from the measurement signal.
- Fluorescence sensor system e.g. According to FIG. 5, a cancer diagnosis without a marker is even possible. This is due to the following effect.
- porphyrins seem to accumulate - even without any marker. When illuminated with short-wave light, these fluoresce in the spectral range approximately at 630 nm.
- a spectrum of this - endogenous - fluorescence is shown in FIG. 12 using the example of a glioblastoma.
- the spectral range to be measured is thus about 630 nm, but is very much superimposed on the fluorescence background.
- the fluorescence background is about one order of magnitude higher than the fluorescence intensity of the porphyrins to be measured.
- the measurement signal of the background fluorescence intensity (reference channel) is subtracted from the measurement signal of the fluorescence intensity to be measured.
- this characteristic porphyrin fluorescence is not observed, so that a diagnosis of certain malignant tumors is possible.
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Application Number | Priority Date | Filing Date | Title |
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DE102005061674A DE102005061674B4 (de) | 2005-12-21 | 2005-12-21 | Faseroptisches Fluoreszenzsensorsystem |
PCT/EP2006/012303 WO2007079943A1 (de) | 2005-12-21 | 2006-12-20 | Faseroptisches fluoreszenzsensorsystem |
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EP1974202A1 true EP1974202A1 (de) | 2008-10-01 |
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EP06841049A Withdrawn EP1974202A1 (de) | 2005-12-21 | 2006-12-20 | Faseroptisches fluoreszenzsensorsystem |
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EP (1) | EP1974202A1 (de) |
DE (1) | DE102005061674B4 (de) |
WO (1) | WO2007079943A1 (de) |
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DE102007047093B4 (de) * | 2007-10-01 | 2010-07-01 | Ferton Holding S.A. | Vorrichtung zur Messung von Fluoreszenzstrahlung an biologischen Substanzen mit einer Halbleitersensorenanordnung |
DE102008011013B4 (de) * | 2008-02-25 | 2014-11-13 | Mevitec Gmbh | Verfahren und Einrichtung zur komplexen Stoffwechselanalyse |
DE102008001322A1 (de) * | 2008-04-22 | 2009-10-29 | Linos Photonics Gmbh & Co. Kg | System zur optischen Analyse von Probenarrays |
DE102011100507B4 (de) * | 2011-04-29 | 2020-05-14 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Tragbares optisches Analysegerät |
DE102012002086A1 (de) * | 2012-02-06 | 2013-08-08 | Carl Zeiss Meditec Ag | Verfahren zum Untersuchen von biologischem Gewebe und Vorrichtungen zum Untersuchen und Behandeln des Gewebes |
CN103175815A (zh) * | 2013-03-06 | 2013-06-26 | 浙江大学 | 多波长led诱导荧光的茶叶品质无损检测方法及装置 |
DE102013008003B4 (de) * | 2013-05-08 | 2015-03-19 | Freshdetect Gmbh | Messgerät zum Messen eines Oberflächenbelags auf einem Messobjekt, insbesondere auf einem Lebensmittel, und dessen Verwendung |
DE102013108189A1 (de) * | 2013-07-31 | 2015-02-05 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG | Anordnung zur optischen Messung einer Prozessgröße und Messgerät umfassend eine solche |
DE102016109819B4 (de) | 2016-05-27 | 2020-07-02 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Vorrichtung und Verfahren zum Erfassen von Ablagerungen an einer Oberfläche einer Wand eines Behältnisses oder Rohres |
TWI586957B (zh) | 2016-06-24 | 2017-06-11 | 諾貝爾生物有限公司 | 多通道螢光檢測系統及其方法 |
EP3438624A1 (de) * | 2017-08-02 | 2019-02-06 | Senmark Invest Oü | Vorrichtung und verfahren für spektral reduzierte fluoreszenzspektroskopie |
WO2022044051A1 (en) * | 2020-08-28 | 2022-03-03 | INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT Madras) | Fiber optic measurement device |
Family Cites Families (11)
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JPS5940830A (ja) * | 1982-08-31 | 1984-03-06 | 浜松ホトニクス株式会社 | レ−ザ光パルスを用いた癌の診断装置 |
AT384891B (de) * | 1983-12-09 | 1988-01-25 | Avl Verbrennungskraft Messtech | Messeinrichtung zur bestimmung der konzentration von halogeniden und pseudohalogeniden, sowie verfahren zur herstellung eines sensorelementes fuer eine derartige einrichtung |
DE3518527A1 (de) * | 1985-05-23 | 1986-11-27 | Ulrich 8700 Würzburg Schliwa | Fluorometer auf impulsbasis |
AT390145B (de) * | 1986-01-27 | 1990-03-26 | Avl Verbrennungskraft Messtech | Verfahren zur bestimmung der konzentration von in einer substanz enthaltenen stoffen, insbesondere von sauerstoff |
US5647368A (en) * | 1996-02-28 | 1997-07-15 | Xillix Technologies Corp. | Imaging system for detecting diseased tissue using native fluorsecence in the gastrointestinal and respiratory tract |
US5914247A (en) * | 1998-03-03 | 1999-06-22 | The United States Of America As Represented By The Secretary Of Agriculture | Method and system for detecting fecal and ingesta contamination on the carcasses of meat animals |
US6252689B1 (en) * | 1998-04-10 | 2001-06-26 | Aircuity, Inc. | Networked photonic signal distribution system |
US6064899A (en) * | 1998-04-23 | 2000-05-16 | Nellcor Puritan Bennett Incorporated | Fiber optic oximeter connector with element indicating wavelength shift |
DE19857792A1 (de) * | 1998-12-15 | 2000-07-20 | Ulrich Schreiber | Ultraempfindliches Chlorophyllfluorometer |
DE10252313B9 (de) * | 2002-11-11 | 2006-10-19 | Carl Zeiss | Untersuchungssystem zur gleichzeitigen direkten Sichtbarmachung einer Fluoreszenzmarkierung und eines die Fluoreszenzmarkierung umgebenden Gewebebereichs und Untersuchungsverfahren dafür |
DE102004001856B4 (de) * | 2003-01-14 | 2019-05-23 | J. Morita Mfg. Corp. | Bilderstellungsgerät für Diagnosezwecke |
-
2005
- 2005-12-21 DE DE102005061674A patent/DE102005061674B4/de not_active Expired - Fee Related
-
2006
- 2006-12-20 WO PCT/EP2006/012303 patent/WO2007079943A1/de active Application Filing
- 2006-12-20 EP EP06841049A patent/EP1974202A1/de not_active Withdrawn
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See references of WO2007079943A1 * |
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DE102005061674B4 (de) | 2008-01-10 |
WO2007079943A1 (de) | 2007-07-19 |
DE102005061674A1 (de) | 2007-07-05 |
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