WO2010092784A1 - 蛍光検出装置及び蛍光検出方法 - Google Patents
蛍光検出装置及び蛍光検出方法 Download PDFInfo
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- 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
- G01N21/6408—Fluorescence; Phosphorescence with measurement of decay time, time resolved fluorescence
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- 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
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1468—Optical investigation techniques, e.g. flow cytometry with spatial resolution of the texture or inner structure of the particle
- G01N15/147—Optical investigation techniques, e.g. flow cytometry with spatial resolution of the texture or inner structure of the particle the analysis being performed on a sample stream
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N2015/0038—Investigating nanoparticles
Definitions
- the present invention relates to a fluorescence detection apparatus and a fluorescence detection method for performing signal processing of a fluorescence signal obtained by receiving fluorescence emitted from a measurement object that has been irradiated with a laser beam.
- a flow cytometer used in the medical and biological fields incorporates a fluorescence detection device that receives fluorescence from a fluorescent dye of a measurement object by irradiating laser light and identifies the type of the measurement object. .
- a flow cytometer labels cells, DNA, RNA, enzymes, proteins, and other biological materials in suspension with a fluorescent reagent and applies pressure to the inside of the pipe line at a speed of about 10 m / sec.
- the measurement object is allowed to flow in the flowing sheath liquid. Thereby, a laminar sheath flow is formed.
- the fluorescence emitted from the fluorescent dye attached to the measurement object is received, and the measurement object is specified by identifying this fluorescence as a label.
- This flow cytometer can measure, for example, the relative amounts of intracellular DNA, RNA, enzymes, proteins, and the like, and can analyze their functions in a short time.
- a cell sorter or the like that identifies specific types of cells and chromosomes by fluorescence and selects and collects only the identified cells and chromosomes in a live state is used. In the use of this, it is required to specify more measurement objects accurately from fluorescence information in a short time.
- Patent Document 1 many measurement objects can be accurately identified in a short time by calculating the fluorescence lifetime (fluorescence relaxation time) of fluorescence emitted from the measurement object by laser light irradiation.
- a fluorescence detection apparatus and method are described.
- the laser beam is intensity-modulated and irradiated to the measurement object, and the phase delay of the fluorescence signal of the fluorescence from the measurement object with respect to the modulation signal used for the laser beam intensity modulation is obtained.
- the calculation of fluorescence relaxation time is described.
- the fluorescence relaxation time can be determined with high accuracy in a short time, but the range in which the fluorescence relaxation time can be determined with a certain degree of accuracy (the range of values of the fluorescence relaxation time) is a limited range. It was. This is due to the fact that the contribution of the phase delay to the fluorescence relaxation time is not constant but changes nonlinearly. That is, the calculation accuracy of the fluorescence relaxation time greatly varies depending on the phase delay value. In addition, there are cases where the phase lag changes due to variation error of each component device and the fluorescence relaxation time changes greatly. For this reason, there is a problem that the fluorescence relaxation time cannot be calculated with a certain accuracy.
- an object of the present invention is to provide a fluorescence detection apparatus and a fluorescence detection method capable of calculating the fluorescence relaxation time over a wide range with a certain accuracy and with a high accuracy in order to solve the above problems. To do.
- One embodiment of the present invention is a fluorescence detection device that performs signal processing of a fluorescence signal obtained by receiving fluorescence emitted from a measurement object that has been irradiated with laser light.
- the device is A light source unit that modulates the intensity of the laser beam applied to the measurement object and emits the laser beam; A light receiving unit that outputs a fluorescence signal of fluorescence emitted from a measurement object irradiated with laser light; A light source control unit that generates a modulation signal for intensity-modulating laser light emitted from the light source unit; A processing unit that calculates a phase delay of the fluorescence emitted from the measurement object with respect to the modulation signal from the fluorescence signal output from the light receiving unit, and calculates a fluorescence relaxation time of the fluorescence of the measurement object using the phase delay; , And a signal control unit that controls the frequency of the modulation signal so that the phase delay value approaches a preset value.
- Another embodiment of the present invention is a fluorescence detection method that performs signal processing of a fluorescence signal obtained by receiving fluorescence emitted from a measurement object that has been irradiated with laser light.
- the fluorescence detection method is: Generating a modulation signal for intensity-modulating the laser light emitted from the laser light source unit, and modulating the laser light using the modulation signal; Obtaining a fluorescence signal of fluorescence emitted from the measurement object irradiated with the laser light; Calculating a phase delay of fluorescence with respect to the modulation signal from the fluorescence signal; Controlling the frequency of the modulation signal so that the value of the phase delay approaches a preset value; Calculating a fluorescence relaxation time of the fluorescence emitted from the measurement object using a phase delay obtained under the condition of the frequency of the modulation signal when the control is settled.
- the frequency of the modulation signal of the laser light is adjusted so that the phase delay approaches a preset value, thereby reducing the phase delay fluorescence.
- Nonlinear contribution to time can be made constant.
- the range which can calculate fluorescence relaxation time with a fixed precision can be expanded.
- the non-linear portion tan ⁇ ( ⁇ is a phase lag) can be set to a substantially constant value without being limited to the fluorescence relaxation time, and thus the phase lag ⁇ is large.
- tan ⁇ differs greatly between the case and the case, and it is possible to prevent the accuracy from changing.
- the preset value is set to 45 degrees, the phase lag is calculated at a high sensitivity of the phase lag with respect to the frequency of the modulation signal, so that a highly accurate fluorescence relaxation time can be calculated.
- FIG. 2 is a diagram mainly showing a signal flow of the flow cytometer shown in FIG. 1.
- FIG. 2 is a diagram illustrating a schematic configuration of a control / signal processing unit of the flow cytometer illustrated in FIG. 1. It is a figure which shows the schematic structure of the data processing part of the flow cytometer shown in FIG. (A)
- (b) is a figure explaining the effect by adjustment of phase delay (theta) used with the fluorescence detection apparatus and phase detection method of this invention. It is a figure explaining the flow of one Embodiment of the fluorescence detection method of this invention.
- FIG. 1 is a schematic configuration diagram of a flow cytometer 10 using the fluorescence detection device of the present invention.
- FIG. 2 is a diagram mainly showing the signal flow of the flow cytometer 10.
- the flow cytometer 10 mainly includes a laser light source unit 22, light receiving units 24 and 26, a control / signal processing unit 28, a data processing unit (computer) 30, a pipe line 32, and a collection container 34.
- a laser light source unit 22 light receiving units 24 and 26
- control / signal processing unit 28 a data processing unit (computer) 30
- pipe line 32 a pipe line 32
- collection container 34 a collection container 34.
- the laser light source unit 22 emits laser light having a wavelength in the visible light band of 350 nm to 800 nm and intensity-modulated by a controlled modulation signal. In the modulation signal, the frequency to be modulated and the signal level of the DC component are controlled.
- the laser light source unit 22 includes a laser light source 22a, a lens system 22b (see FIG. 2), and a laser driver 22c (see FIG. 2).
- the laser light source 22a emits laser light having a predetermined wavelength as CW (continuous wave) laser light having a constant intensity, and emits the CW laser light while modulating the intensity with frequency.
- the lens system 22 b focuses the laser beam on a predetermined measurement point (measurement field) in the pipe line 30.
- the laser driver 22c drives a laser light source.
- the laser light source unit 22 is configured by one laser light source, but is not limited to one laser light source.
- the laser light source unit 22 can use a plurality of laser light sources. In this case, it is preferable to combine laser light from a plurality of laser light sources using a dichroic mirror or the like to form laser light emitted toward the measurement field.
- a semiconductor laser is used as a light source for emitting laser light.
- the laser beam has an output of about 5 to 100 mW, for example.
- the frequency (modulation frequency) for modulating the intensity of the laser light is slightly longer than the fluorescence relaxation time, for example, 10 to 200 MHz.
- the laser driver 22c provided in the light source unit 22 is configured such that the level of the DC component of the intensity of the laser beam and the frequency of intensity modulation are controlled. That is, the intensity of the laser beam shows an intensity change in which intensity modulation is applied to the DC component, and the minimum intensity is greater than zero.
- the light receiving unit 24 includes a photoelectric converter 24a (see FIG. 2), a lens system 24b (see FIG. 2) for converging forward scattered light to the photoelectric converter 24a, and a shielding plate 24c (see FIG. 2).
- the photoelectric converter 24a is arranged so as to face the laser light source unit 22 with the pipe line 32 interposed therebetween, and the sample 12 receives the laser light scattered forward by the sample 12 passing through the measurement field, so that the sample 12 has a measurement point. A detection signal indicating that it passes is output.
- the shielding plate 24c is provided on the front surface of the lens system 24b so that the laser light does not directly enter the photoelectric converter 24a.
- the signal output from the light receiving unit 24 is supplied to the control / signal processing unit 28 and the data processing unit 30, and the sample 12 passes through the measurement point in the pipe 32 in the control / signal processing unit 28 and the data processing unit 30. It is used as a trigger signal for informing the timing to perform, and an OFF signal at the end of measurement.
- the light receiving unit 26 is arranged in a direction perpendicular to the emitting direction of the laser light emitted from the laser light source unit 22 and perpendicular to the moving direction of the sample 12 in the pipe line 32.
- a photoelectric converter 26a (see FIG. 2) that receives fluorescence emitted from the sample 12 irradiated at the measurement point is provided.
- the light receiving unit 26 includes a lens system 26b (see FIG. 2) that focuses the fluorescent signal from the sample 12, and a bandpass filter 26c (see FIG. 2).
- the lens system 26b is configured to focus the fluorescence incident on the light receiving unit 26 on the light receiving surface of the photoelectric converter 26a.
- the bandpass filter 26c has a transmission wavelength band that is filtered so that fluorescence of a predetermined wavelength band is captured by the photoelectric converter 26a.
- the light receiving unit 26 includes one photoelectric converter 26a, in the present embodiment, the light receiving unit 26 may include a plurality of photoelectric converters. In this case, a dichroic mirror can be provided in front of the bandpass filler 26c to divide the fluorescence into frequency bands, and the photoelectric converters can receive the divided fluorescence.
- the band pass filter 26c is a filter that is provided in front of the light receiving surface of each photoelectric converter 26a and transmits only fluorescence in a predetermined wavelength band.
- the wavelength band of the transmitted fluorescence is set corresponding to the wavelength band of the fluorescence emitted by the fluorescent dye.
- the photoelectric converter 26a includes, for example, a photomultiplier tube as a sensor.
- the photoelectric converter 26a converts light received by the photocathode into an electrical signal.
- the received fluorescence is fluorescence emitted by intensity modulation as in the case of laser light intensity modulation, so that the output fluorescence signal is a signal having the same frequency as the laser light intensity modulation frequency. This fluorescence signal is supplied to the control / signal processing unit 28.
- FIG. 3 is a diagram illustrating a configuration of the control / signal processing unit 28.
- the control / signal processing unit 28 includes a modulation signal control unit 40, a frequency conversion unit 42, and an AD conversion unit 44.
- the modulation signal control unit 40 generates a modulation signal for intensity modulation of the laser light and supplies it to the laser driver 22c. Further, the modulation signal control unit 40 supplies the generated modulation signal to the frequency conversion unit 42.
- the modulation signal control unit 40 includes a variable frequency oscillator 40a, a power splitter 40b, amplifiers 40c and 40d, a DC signal generator 40e, and a frequency counter 40f.
- the variable frequency oscillator 40a oscillates at a frequency determined according to a control signal from the data processing unit 30, and generates a modulation signal.
- a voltage control generator is preferably used for the frequency variable oscillator 40a.
- the power splitter 40b equally distributes the oscillated modulation signal and supplies it to the amplifier 40c and the amplifier 40d, respectively.
- the amplifier 40c amplifies the modulation signal and supplies it to the laser driver 22c.
- the amplifier 40d supplies the frequency converter 42 described later. The reason why the modulation signal is supplied to the frequency conversion unit 42 is to use it as a reference signal in order to calculate the phase delay of the fluorescence signal output from the light receiving unit 26 with respect to the modulation signal.
- the DC signal generator 40e generates a DC component of the modulation signal and supplies it to the laser driver 22c.
- the DC component is supplied to the laser driver 22c by adjusting the intensity of the laser light so that the intensity of the fluorescence emitted from the sample 12 is adjusted to a predetermined intensity. This is for calculating a high fluorescence relaxation time. That is, the intensity of the laser beam shows an intensity change in which intensity modulation is applied to the DC component, and the minimum intensity is set to be greater than zero.
- the frequency counter 40f counts the frequency of the modulation signal oscillated by the frequency variable oscillator 40a. The count result of the frequency counter 40f is supplied to the data processing unit 30.
- the variable frequency oscillator 40a and the DC signal generator 40e are respectively connected to the data processing unit 30, and the frequency of the modulation signal and the signal level of the DC component are controlled by the control signal from the data processing unit 30.
- the frequency conversion unit 42 performs frequency conversion on the fluorescent signal supplied from the light receiving unit 26a to perform down conversion.
- the frequency conversion unit 42 mainly includes a variable amplifier 42a, an IQ mixer 42b, and a low-pass filter 42c.
- the variable amplifier 42a is a part that amplifies the fluorescence signal.
- the variable amplifier 42 a is connected to the data processing unit 30, and the gain is controlled according to the control signal from the data processing unit 30.
- the IQ mixer 42b performs frequency conversion (down-conversion) of the amplified fluorescence signal to a low frequency using the modulation signal supplied from the modulation signal control unit 40 as a reference signal, and the fluorescence signal is in phase with the modulation signal. A modulation signal whose phase is 90 degrees out of phase with the signal is generated.
- the IQ mixer 42b includes a 90-degree phase shifter 42d (see FIG. 2) and mixers 42e (see FIG. 2) and 42f (see FIG. 2).
- the 90-degree phase shifter 42d generates a signal whose phase is 90 degrees shifted from the modulation signal, and the modulation signal whose phase is in phase and the modulation signal whose phase is 90 degrees are supplied to the mixers 42e and 42f, respectively.
- the supplied modulated signal having the same phase as that of the modulated signal whose phase is shifted by 90 degrees is used as a reference signal, and mixing processing is performed on the amplified fluorescence signal.
- the mixed fluorescence signal is supplied to the low-pass filter 42c.
- the low-pass filter 42c filters a signal in a predetermined frequency region lower than the modulation signal from the mixed fluorescent signal, and extracts a low-frequency signal.
- the Re component and the Im component of the fluorescent signal having the signal component in the frequency 0 region as the main component are obtained.
- the obtained Re component and Im component are supplied to the AD conversion unit 44.
- the AD conversion unit 44 is a part that converts the supplied Re component and Im component into digital data.
- the AD conversion unit 44 includes an amplifier 44a and an AD converter 44b.
- the amplifier 44a amplifies the Re component and the Im component with a predetermined gain, and then supplies them to the AD converter 44b.
- the AD converter 44 b converts the amplified Re component and Im component into digital data, and supplies the digitized Re component data and Im component data to the data processing unit 30.
- the data processing unit 30 obtains the fluorescence phase lag ⁇ and the value of the fluorescence intensity signal using the supplied Re component data and Im component data. Further, the data processing unit 30 detects that the value of the phase delay ⁇ approaches a preset value and the value of the fluorescence intensity signal, specifically, the value of the fluorescence intensity signal falls within the preset intensity range. Is used to calculate the fluorescence relaxation time ⁇ and the fluorescence intensity of the fluorescence at that time. More specifically, until the calculated fluorescence intensity signal value falls within a preset intensity range, the level of the DC component generated by the DC signal generator 40e or the gain of the variable amplifier 42a is adjusted.
- the modulation signal is controlled by generating a control signal for adjusting the frequency of the modulation signal generated by the frequency variable oscillator 40a so that the calculated value of the phase delay ⁇ approaches a preset value.
- the preset value can be set to 25 to 65 degrees from which the value of the change in the phase delay ⁇ with respect to the change in the angular frequency can be taken from the graph shown in FIG. Of these, the angle is preferably 45 degrees.
- To approach the preset value means that the value of the phase delay ⁇ after the control is closer to the preset value than the value of the phase delay ⁇ before the control before and after the control of the modulation signal. means.
- the value of the phase delay ⁇ approaches the target value set in advance by this control, but it is preferable that the phase delay ⁇ converges within a preset allowable range with respect to the target value.
- the allowable range is, for example, ⁇ 10 degrees, ⁇ 5 degrees, or ⁇ 2 degrees, depending on the accuracy with which the target fluorescence relaxation time is calculated.
- FIG. 4 is a diagram illustrating a schematic configuration of the data processing unit 30.
- the data processing unit 30 includes a fluorescence intensity signal generation unit 30a, a fluorescence intensity calculation unit 30b, a phase lag calculation unit 30c, a signal control unit 30d, and a fluorescence relaxation time calculation unit 30e.
- Each of these parts is a module formed by executing a program executable by a computer. That is, the data processing unit 30 generates each function by starting software on the computer.
- the phase delay calculation unit 30c and the fluorescence relaxation time calculation unit 30e calculate at least the fluorescence phase delay with respect to the modulation signal from the fluorescence signal, and calculate the fluorescence relaxation time of the fluorescence of the sample 12 using this phase delay.
- the fluorescence intensity signal generation unit 30a generates a fluorescence intensity signal by square-adding the Re component data and Im component data supplied from the AD converter 44b to obtain a square root.
- the calculated fluorescence intensity signal is sent to the fluorescence intensity calculator 30b. Since the value of the fluorescence intensity signal is a value obtained by adjusting the DC component of the laser light and the gain of the variable amplifier 42a, the value changes greatly according to these adjustment results. Therefore, in the fluorescence intensity calculation unit 30b, the fluorescence intensity signal is corrected using information on the level and gain of the DC component that is the intensity of the laser light, and the fluorescence intensity is calculated. However, this correction is performed only when a determination instruction (to be described later) is received from the signal control unit 30d.
- the fluorescence intensity signal is time-series data calculated using Re component data and Im component data that are continuously supplied during a period in which the sample 12 passes through the laser beam measurement field.
- the fluorescence intensity calculation unit 30b converts the fluorescence intensity signal generated by the fluorescence intensity signal generation unit 30a into information on the level and gain of the DC component that is the intensity of the laser light. And correct the fluorescence intensity. Specifically, the fluorescence intensity is obtained by dividing the value of the fluorescence intensity signal by a coefficient determined from the DC component level and the value of the control signal for adjusting the gain of the variable amplifier 42a. The coefficient used for the division is obtained by referring to the LUT in which the DC component level and gain adjustment control signal values are associated with the coefficients.
- the DC component of the laser light used for correction may be a signal value given by the control signal, or the intensity of forward scattered light measured by the light receiving unit 24 may be used.
- the gain of the variable amplifier 42a may be a signal value given by the control signal, or a value obtained by separately measuring the gain may be used.
- the determination instruction received from the signal control unit 30d is issued when the value of the fluorescence intensity signal under control generated by the fluorescence intensity signal generation unit 30a exceeds a predetermined set value and reaches a maximum value.
- the predetermined set value is a lower limit value that defines a preset range.
- the fluorescence intensity can be obtained by dividing the value of the fluorescence intensity signal at this time by the value of the control signal.
- the level of the DC component generated by the DC signal generator 40e and the gain of the variable amplifier 42a are adjusted so that the value of the fluorescence intensity signal falls within a preset intensity range. In the latter half of the measurement field, the fluorescence intensity signal becomes weak. At this time, the adjustment of the level of the DC component generated by the DC signal generator 40e and the gain of the variable amplifier 42a (adjustment of the operation amount) does not reach the target value even if the operation amount is maximized. On the other hand, the fluorescence intensity signal gradually increases at the stage from the first half to the middle where the sample 12 passes through the measurement field. Therefore, once the fluorescence intensity signal enters a preset range at this stage, the operation amount is adjusted.
- the fluorescence intensity calculation method integrates the value obtained by dividing the value of the fluorescence intensity signal being controlled by the coefficient determined by the value of the control signal during the control time, and this integrated value is calculated for the control time.
- the value divided by can also be calculated as the fluorescence intensity value.
- the phase delay calculation unit 30c calculates tan ⁇ 1 (Im / Re) (Im is the value of Im component data and Re is the value of Re component data) using the supplied Re component data and Im component data. Thus, the phase delay ⁇ is calculated.
- the calculated phase delay ⁇ is supplied to the signal control unit 30d. Further, the calculated phase delay ⁇ is supplied to the fluorescence relaxation time calculation unit 30e.
- the reason why the fluorescence relaxation time ⁇ can be obtained according to the above equation is that the fluorescence follows a relaxation response with a substantially first-order lag.
- the frequency f of the modulation signal the frequency count result of the modulation signal supplied from the frequency counter 40f is used. Instead of using the frequency count result, the target frequency of the modulation signal determined by the signal control unit 30 using the control signal may be used.
- the signal control unit 30d determines whether or not the phase delay ⁇ supplied from the firefly phase lag calculation unit 30c and the value of the fluorescence intensity signal generated by the light intensity signal generation unit 30a are within separately set ranges.
- the control signal is generated according to the determination result.
- the signal control unit 30d controls the frequency of the modulation signal so that the value of the phase delay ⁇ approaches a preset value, for example, 45 degrees.
- the signal control unit 30d generates a control signal for adjusting the oscillation frequency of the frequency variable oscillator 40a so that the value of the phase delay ⁇ approaches a preset value, and supplies the control signal to the frequency variable oscillator 40a.
- the modulation signal with the adjusted frequency is supplied to the laser driver 22c, and the intensity modulation of the laser light is adjusted.
- the signal control unit 30d when the value of the phase delay ⁇ matches 45 degrees within the set allowable range, a highly accurate phase delay ⁇ is obtained according to the determination result of the value of the fluorescence intensity signal described later. judge.
- the signal control unit 30d controls the level of the DC component of the laser light emitted from the light source unit 22 and the gain of the variable amplifier 44b so that the value of the fluorescence intensity signal falls within a preset range.
- a control signal for adjusting the signal level of the DC component of the DC signal generator 40e is generated and supplied to the DC signal generator 40e.
- the modulation signal whose DC component signal level has been adjusted is supplied to the laser driver 22c, and the intensity modulation of the laser light is adjusted.
- a modulated signal with the signal level of the DC component adjusted is supplied to the laser driver 22c.
- the modulation signal of the DC signal generator 40e is controlled and the gain of the variable amplifier 26a is controlled, but only the modulation signal may be controlled.
- the signal control unit 30d determines that a highly accurate phase delay ⁇ is obtained when the phase delay ⁇ is in a preset range and the value of the fluorescence intensity signal is in a set range, and calculates the fluorescence intensity.
- the unit 30b and the fluorescence relaxation time calculation unit 30e are instructed to determine calculation of fluorescence intensity and calculation of fluorescence relaxation time.
- FIG. 5A shows the relationship between the intensity modulation frequency (angular frequency 2 ⁇ f) of the laser beam and the phase delay ⁇ of the fluorescence at that time with respect to various fluorescence relaxation times ⁇ .
- the sensitivity of the phase delay ⁇ is high at an angle of 45 degrees. Therefore, by controlling the frequency of the modulation signal so that the phase delay ⁇ approaches the target value of 45 degrees, the phase delay ⁇ can be calculated at a highly sensitive position. That is, a highly accurate phase delay ⁇ can be calculated.
- FIG. 6 is a diagram illustrating a flow of an embodiment of the fluorescence detection method performed by the fluorescence detection apparatus 10. This embodiment is a method of adjusting the DC component of the intensity of the laser light, the amplification gain of the fluorescence signal immediately after receiving the fluorescence, and the frequency of the modulation signal in order to calculate the fluorescence intensity and the fluorescence relaxation time.
- the modulation signal control unit 40 sets the signal level of the DC component of the modulation signal used for intensity modulation of the laser beam and the gain of the variable amplifier 42a of the frequency conversion unit 42. (Step S10). At the start of processing, the signal level and gain of the DC component set as default are set. Further, the modulation signal control unit 40 sets the frequency of the modulation signal based on the control signal from the data processing unit 30. For example, the frequency is set as a default. A modulation signal is generated using the set signal level and gain of the DC component and the frequency of the modulation signal, and laser light whose intensity is modulated is emitted from the laser light source 22a (step S12).
- the laser beam is irradiated, and the fluorescence emitted from the sample 12 passing through the measurement field is received by the light receiving unit 26a, and the fluorescence signal is output (step S14).
- the signal is amplified with the gain set by the variable amplifier 42a, supplied to the mixers 42e and 42f, and mixed to obtain the Re component and the Im component.
- the Re component and the Im component are converted into digital signals by the AD conversion unit 44, and Re component data and Im component data are obtained (step S16).
- the phase delay calculation unit 30c of the data processing unit 30 calculates the phase delay ⁇ of the fluorescence signal from the digitized Re component data and Im component data (step S18).
- the signal control unit 30d determines whether or not the calculated phase delay ⁇ matches the preset target value of 45 degrees within an allowable range (step S20).
- a control signal for changing the frequency of the modulation signal is generated and supplied to the variable frequency oscillator 40a.
- the frequency of the modulation signal is changed (step S22).
- steps S10 to S22 are repeated so that the phase delay ⁇ approaches the set target value.
- step S24 the signal control unit 30 further determines whether or not the value of the fluorescence intensity signal falls within a preset range.
- a determination instruction for calculating the fluorescence intensity and the fluorescence relaxation time is issued to the fluorescence intensity calculation unit 30b and the fluorescence relaxation time calculation unit 30e.
- the fluorescence intensity generated by the fluorescence intensity signal generation unit 30a and the fluorescence relaxation time calculated by the fluorescence relaxation time calculation unit 30e are determined as the measurement result of the sample 12 (step S26).
- step S28 When the value of the fluorescence intensity signal does not fall within the preset range (in the case of No), the signal level and gain of the DC component used for the modulation signal are changed (step S28), and the process returns to step 10. Thus, steps S10 to S24 and step S28 are repeated until the value of the fluorescence intensity signal falls within a preset range.
- the calculated measurement result is output to an output device such as a display or a printer (not shown) together with information such as the signal level of the DC component, the gain, and the frequency of the modulation signal.
- the above-described fluorescence detection method determines whether or not the phase delay ⁇ matches the target value within the allowable range. If the determination result is affirmative, whether or not the value of the fluorescence intensity signal falls within the set range. A process for determining whether or not is used. However, the present embodiment determines whether or not the value of the fluorescence intensity signal falls within the set range, and if the determination result is affirmative, whether or not the phase delay ⁇ matches the target value within the allowable range. You may use the process which determines. The above two determinations may be performed simultaneously.
- the sample 12 is composed of a plurality of sample particles, and the sample particles are considered to pass through a measurement field by laser light intermittently one by one at a constant speed.
- the signal control unit 30d starts controlling the frequency of the modulation signal so that the value of the phase delay approaches a preset value immediately after the sample particle starts to pass through the measurement field irradiated with the laser beam.
- the data processing unit 30 finds the frequency of the modulation signal at which the phase delay value becomes a preset value before the sample particle finishes passing through the laser beam measurement field, and finds the condition of the found frequency.
- the fluorescence relaxation time is calculated from the phase delay obtained in step 1 and the frequency of the modulation signal.
- the signal level of the DC component of the modulation signal and the gain of the variable amplifier 42a are also controlled.
- the time required for the sample particles to pass through the laser beam measurement field is about 10 to 30 ⁇ s, and the frequency variable oscillator 40a can be sufficiently controlled within this time.
- the data processing unit 30 controls the frequency of the modulation signal so that the value of the phase delay approaches a preset value, and the fluorescence relaxation time is calculated from the phase delay and the frequency of the modulation signal when this control is settled. Is calculated.
- the data processing unit 30 simultaneously controls the signal level and gain of the DC component so as to find the signal level and gain of the DC component in which the fluorescence intensity signal falls within a preset range.
- the phase relaxation fluorescence relaxation time when calculating the fluorescence relaxation time, by adjusting the frequency of the modulation signal of the laser light so that the phase delay approaches a preset value, the phase relaxation fluorescence relaxation time is obtained.
- the given nonlinear contribution can be made constant.
- this embodiment can expand the range which can calculate fluorescence relaxation time with a fixed precision.
- tan ⁇ ⁇ being a phase lag
- tan ⁇ that is a non-linear part can be set to a substantially constant value, not limited to the fluorescence relaxation time.
- the contribution of tan ⁇ differs greatly between when the phase delay ⁇ is large and when it is small, and it is possible to prevent the accuracy from changing.
- the phase lag is calculated at a high sensitivity of the phase lag with respect to the frequency of the modulation signal. Therefore, it is possible to calculate the fluorescence relaxation time with high accuracy. Can do.
- the present embodiment can determine the phase delay ⁇ with a certain accuracy in a wide range.
- the signal levels of the Re component and the Im component are low, noise due to the IQ mixer 42b, the low-pass filter 42c, the AD converter 44b, and the like is mixed into the Re component and the Im component, so that errors may be included in these components.
- AD conversion is performed in this state, the quantization error increases, and the error of the phase delay ⁇ calculated thereafter increases.
- the signal levels of the Re component and the Im component can be kept constant by allowing the fluorescence intensity signal calculated from the Re component and the Im component to fall within a preset range.
- this embodiment can suppress the error of phase delay (theta) uniformly, and can also suppress it.
- both are adjusted so that the phase delay and the value of the fluorescence intensity signal fall within the preset range, but without determining whether the value of the fluorescence intensity signal falls within the preset range. It is also possible to determine only whether or not the phase delay falls within a preset range.
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Abstract
Description
このフローサイトメータは、例えば、細胞内のDNA、RNA、酵素、蛋白質等の細胞内相対量を計測し、またこれらの働きを短時間で解析することができる。また、特定のタイプの細胞や染色体を蛍光によって特定し、特定した細胞や染色体のみを生きた状態で短時間で選別収集するセル・ソータ等が用いられる。
これの使用においては、より多くの測定対象物を、短時間に正確に蛍光の情報から特定することが要求されている。
当該文献によると、レーザ光を強度変調して測定対象物に照射し、測定対象物からの蛍光の蛍光信号の、レーザ光の強度変調に用いた変調信号に対する位相遅れを求め、この位相遅れから、蛍光緩和時間を算出することが記載されている。
当該装置は、
測定対象物に照射するレーザ光を強度変調して出射する光源部と、
レーザ光の照射された測定対象物から発する蛍光の蛍光信号を出力する受光部と、
前記光源部から出射するレーザ光を強度変調するための変調信号を生成する光源制御部と、
前記受光部で出力された蛍光信号から、前記変調信号に対する、測定対象物が発する蛍光の位相遅れを算出し、前記位相遅れを用いて測定対象物の蛍光の蛍光緩和時間を算出する処理部と、
前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数を制御する信号制御部と、を有する。
当該蛍光検出方法は、
レーザ光源部から出射するレーザ光を強度変調するための変調信号を生成し、前記変調信号を用いてレーザ光を変調するステップと、
前記レーザ光の照射された測定対象物から発する蛍光の蛍光信号を取得するステップと、
前記蛍光信号から、前記変調信号に対する蛍光の位相遅れを算出するステップと、
前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数を制御するステップと、
前記制御が整定したときの前記変調信号の周波数の条件で得られる位相遅れを用いて、測定対象物の発する蛍光の蛍光緩和時間を算出するステップと、を有する。
特に、予め設定された値を45度にすることにより、変調信号の周波数に対する位相遅れの感度の高いところで位相遅れが算出されるので、精度の高い蛍光緩和時間を算出することができる。
図1は、本発明の蛍光検出装置を用いたフローサイトメータ10の概略構成図である。図2は、フローサイトメータ10の信号の流れを中心に示す図である。
フローサイトメータ10は、主に、レーザ光源部22と、受光部24、26と、制御・信号処理部28と、データ処理部(コンピュータ)30と、管路32と、回収容器34と、を有する。
レーザ光源部22は、レーザ光源22aと、レンズ系22b(図2参照)と、レーザドライバ22c(図2参照)と、を有する。レーザ光源22aは、所定の波長のレーザ光を強度が一定のCW(連続波)レーザ光として出射し、かつこのCWレーザ光の強度を周波数で変調しながら出射する。レンズ系22bは、レーザ光を管路30中の所定の測定点(測定場)に集束させる。レーザドライバ22cは、レーザ光源を駆動する。レーザ光源部22は、1つのレーザ光源で構成されるが、1つのレーザ光源に限定されない。レーザ光源部22は、複数のレーザ光源を用いることもできる。この場合、複数のレーザ光源からのレーザ光を、ダイクロイックミラー等を用いて合成して、測定場に向けて出射されるレーザ光を形成することが好ましい。
光電変換器24aは、管路32を挟んでレーザ光源部22と対向するように配置されており、測定場を通過する試料12によって前方散乱するレーザ光を受光することにより、試料12が測定点を通過する旨の検出信号を出力する。
遮蔽板24cは、レーザ光が光電変換器24aに直接入射しないようにレンズ系24bの前面に設けられている。この受光部24から出力される信号は、制御・信号処理部28およびデータ処理部30に供給され、制御・信号処理部28およびデータ処理部30において試料12が管路32中の測定点を通過するタイミングを知らせるトリガ信号、測定終了のOFF信号として用いられる。
レンズ系26bは、受光部26に入射した蛍光を光電変換器26aの受光面に集束させるように構成されている。バンドパスフィルタ26cは、フィルタリングして光電変換器26aで所定の波長帯域の蛍光が取り込まれるように、透過波長帯域が設定されている。
受光部26は、1つの光電変換器26aを有するが、本実施形態では、受光部26は、複数の光電変換器を有することもできる。この場合、ダイクロイックミラーをバンドパスフィラー26cの前に設けて、蛍光を周波数帯域別に分け、この分けた蛍光を光電変換器それぞれが受光するように構成することができる。
光電変換器26aは、例えば光電子増倍管をセンサとして備える。光電変換器26aは、光電面で受光した光を電気信号に変換する。ここで、受光する蛍光は、レーザ光の強度変調と同様に、強度変調して発する蛍光であるので、出力される蛍光信号はレーザ光の強度変調の周波数と同じ周波数を持った信号となる。この蛍光信号は、制御・信号処理部28に供給される。
変調信号制御部40は、レーザ光の強度変調のための変調信号を生成し、レーザドライバ22cに供給する。さらに、変調信号制御部40は、生成した変調信号を周波数変換部42に供給する。
変調信号制御部40は、周波数可変発振器40aと、パワースプリッタ40bと、増幅器40c,40dと、DC信号発生器40eと、周波数カウンタ40fとを有する。
パワースプリッタ40bは、発振した変調信号を均等に分配する部分で、増幅器40cと増幅器40dにそれぞれ供給する。
増幅器40cは、変調信号を増幅してレーザドライバ22cに供給する。増幅器40dは、後述する周波数変換部42に供給する。周波数変換部42に変調信号を供給するのは、受光部26から出力された蛍光信号の、変調信号に対する位相遅れを算出するために、参照信号として用いるためである。
周波数カウンタ40fは、周波数可変発振器40aにて発振した変調信号の周波数をカウントする。周波数カウンタ40fのカウント結果は、データ処理部30に供給される。
周波数可変発振器40aとDC信号発生器40eは、それぞれ、データ処理部30と接続されており、データ処理部30からの制御信号により、変調信号の周波数およびDC成分の信号レベルが制御されている。
可変増幅器42aは、蛍光信号を増幅する部分である。可変増幅器42aは、データ処理部30と接続され、データ処理部30からの制御信号に従ってゲインが制御されている。
IQミキサ42bは、90度位相シフタ42d(図2参照)と、ミキサ42e(図2参照),42f(図2参照)を有する。90度位相シフタ42dにより、変調信号と位相が90度ずれた信号が生成され、位相が同相の変調信号と位相が90度ずれた変調信号がそれぞれミキサ42e、42fに供給される。
ミキサ42e,42fでは、供給された位相が同相の変調信号と位相が90度ずれた変調信号を参照信号とし、増幅された蛍光信号とミキシング処理を行う。ミキシングされた蛍光信号は、ローパスフィルタ42cに供給される。
ローパスフィルタ42cは、ミキシングされた蛍光信号から、変調信号より低い所定の周波数領域の信号をろ過し、低周波信号を取り出す。これにより、周波数0領域の信号成分を主成分とする、蛍光信号のRe成分とIm成分が求められる。求められたRe成分とIm成分は、AD変換部44に供給される。
より詳しく説明すると、算出された蛍光強度信号の値が、予め設定された強度範囲に入るまで、DC信号発生器40eで生成するDC成分のレベル、あるいは可変増幅器42aのゲインの調整を行うための制御信号を生成することで、AD変換器44bで行うRe成分とIm成分の信号レベルを調整する。さらに、算出された位相遅れθの値が、予め設定された値に近づくように、周波数可変発振器40aで生成する変調信号の周波数を調整するための制御信号を生成することで、変調信号を制御する。予め設定された値は、後述する図5(a)に示すグラフから、角周波数変化に対する位相遅れθの変化の値を大きくとることのできる25~65度に設定することができる。この中で特に45度とするのが好ましい。予め設定された値に近づくとは、変調信号の制御の前と後では、制御後の位相遅れθの値は、制御前の位相遅れθの値に比べて予め設定された値に近いことを意味する。位相遅れθの値は、この制御により予め設定された目標とする値に近づくが、この目標とする値に対して、予め設定された許容範囲内で収束することが好ましい。許容範囲は、目標とする蛍光緩和時間の算出しようとする精度にも依存するが、例えば、±10度、±5度あるいは±2度である。位相遅れθの値が、目標とする値に対して予め設定された許容範囲内に入るとき、制御は整定された状態となる。
位相遅れ算出部30cと蛍光緩和時間算出部30eは、少なくとも、蛍光信号から、変調信号に対する蛍光の位相遅れを算出し、この位相遅れを用いて試料12の蛍光の蛍光緩和時間を算出する処理部に対応する。
なお、蛍光強度信号は、試料12がレーザ光の測定場を通過する期間に連続して供給されるRe成分データとIm成分データを用いて算出される時系列データである。
補正に用いるレーザ光のDC成分は、制御信号が与える信号値でもよいし、受光部24で計測された前方散乱光の強度を用いることもできる。可変増幅器42aのゲインは、制御信号が与える信号値でもよいし、ゲインを別途計測した結果の値を用いることもできる。
信号制御部30dから受ける決定指示は、蛍光強度信号生成部30aで生成される制御中の蛍光強度信号の値が所定の設定値を超えて最大値になったときに出される。ここで、所定の設定値とは、予め設定された範囲を定める下限値である。このときの蛍光強度信号の値を制御信号の値で除算することにより、蛍光強度が得られる。
蛍光強度信号の値は、予め設定された強度範囲に入るように、DC信号発生器40eで生成するDC成分のレベルおよび可変増幅器42aのゲインの調整(操作量の調整)を行うが、試料12が測定場を通過する後半部は、蛍光強度信号が弱くなる。このとき、DC信号発生器40eで生成するDC成分のレベルおよび可変増幅器42aのゲインの調整(操作量の調整)では、操作量を最大にしても目標値に達しない。一方、試料12が測定場を通過する前半部~中間部の段階では、蛍光強度信号が徐々に強くなるので、この段階において蛍光強度信号が予め設定された範囲に一旦入ると、操作量は調整されず一定となる。このとき、蛍光強度信号の値は、上記範囲を定める設定値を超えて最大値になる。したがって、このときの蛍光強度信号を、このときの制御信号の値で定まる係数で除算することにより、補正した蛍光強度を求める。
蛍光強度の算出方法は、上記方法により値を算出する他に、制御中の蛍光強度信号の値を制御信号の値で定まる係数で除算した値を制御時間中積算し、この積算値を制御時間で除算した値を、蛍光強度の値として算出することもできる。
位相遅れ算出部30cは、供給されたRe成分データとIm成分データを用いてtan-1(Im/Re)(ImはIm成分データの値、ReはRe成分データの値である)を算出することで、位相遅れθを算出する。算出された位相遅れθは信号制御部30dに供給される。また、算出された位相遅れθは蛍光緩和時間算出部30eに供給される。
信号制御部30dで、位相遅れθの値が設定された許容範囲内で45度に一致する場合、後述する蛍光強度信号の値の判定結果に応じて、精度の高い位相遅れθが得られたと判定する。
また、信号制御部30dは、蛍光強度信号の値が予め設定された範囲に入るように、光源部22から出射されるレーザ光のDC成分のレベルおよび可変増幅器44bのゲインを制御する。
判定結果、蛍光強度信号の値が設定された範囲に入らない場合、DC信号発生器40eのDC成分の信号レベルを調整する制御信号を生成し、DC信号発生器40eに供給する。これにより、レーザドライバ22cにDC成分の信号レベル調整された変調信号が供給され、レーザ光の強度変調は調整される。これにより、レーザドライバ22cにDC成分の信号レベルの調整された変調信号が供給される。また、受光部26a直後に設けられた可変増幅器42aのゲインを調整する制御信号を生成し、可変増幅器42aのゲインを制御する。
本実施形態は、DC信号発生器40eの変調信号の制御と可変増幅器26aのゲインの制御を行うが、変調信号の制御のみを行ってもよい。
信号制御部30dは、位相遅れθが予め設定された範囲に入り、かつ、蛍光強度信号の値が設定された範囲に入る場合、精度の高い位相遅れθが得られたと判定し、蛍光強度算出部30b及び蛍光緩和時間算出部30eに、蛍光強度の算出と蛍光緩和時間の算出の決定指示をする。
図5(a)には、レーザ光の強度変調の周波数(角周波数2πf)とそのときの蛍光の位相遅れθとの関係を、種々の蛍光緩和時間τに関して示している。
位相遅れθが45度で角周波数2πfに対する位相遅れθの角度変化が最大となる。すなわち、角度45度で位相遅れθの感度が高くなっている。したがって、位相遅れθが目標値である45度に近づくように変調信号の周波数を制御することにより、感度の高い位置で位相遅れθを算出することができる。すなわち、精度の高い位相遅れθが算出され得る。
さらに、変調信号制御部40において、データ処理部30からの制御信号に基づいて変調信号の周波数が設定される。例えば周波数がデフォルト設定される。以上の設定されたDC成分の信号レベル及びゲインと変調信号の周波数とを用いて変調信号を生成し、レーザ光源22aから強度変調されたレーザ光が出射される(ステップS12)。
次に、可変増幅器42aで設定されたゲインで増幅され、ミキサ42e,42fに供給され、ミキシングされて、Re成分およびIm成分が求められる。さらに、Re成分およびIm成分は、AD変換部44でデジタル信号に変換され、Re成分データおよびIm成分データが得られる(ステップS16)。
次に、信号制御部30dでは、算出された位相遅れθが、予め設定された目標値である45度に許容範囲内で一致するか否かが判定される(ステップS20)。ここで、位相遅れθが許容範囲内で目標値に一致しない場合、変調信号の周波数は変更する制御信号が生成され、周波数可変発振器40aに供給される。こうして、変調信号の周波数が変更される(ステップS22)。ここで、周波数の変更は、算出された位相遅れθを用いて、例えば、周波数f=2πf1/tan(θ)(f1は、現在設定されている変調信号の周波数)となるように行われる。
こうして、位相遅れθが設定された目標値に近づくように、ステップS10~S22を繰り返す。
蛍光強度信号の値が予め設定された範囲に入らない場合(Noの場合)、変調信号に用いるDC成分の信号レベルとゲインが変更され(ステップS28)、ステップ10に戻される。
こうして、蛍光強度信号の値が予め設定された範囲に入るまで、ステップS10~S24及びステップS28が繰り返される。
算出された計測結果は、DC成分の信号レベル、ゲイン、変調信号の周波数等の情報とともに、図示されないディスプレイあるいはプリンタ等の出力装置に出力される。
サンプル粒子がレーザ光の測定場を通過する時間は、10~30μ秒程度であり、この時間内に、周波数可変発振器40aを十分に制御することは可能である。
すなわち、データ処理部30は、位相遅れの値が予め設定された値に近づくように、変調信号の周波数の制御を行い、この制御が整定したときの位相遅れと変調信号の周波数から蛍光緩和時間を算出する。データ処理部30は、この周波数の制御のとき、同時に、蛍光強度信号が予め設定された範囲に入るDC成分の信号レベルおよびゲインを見出すように、DC成分の信号レベルおよびゲインを制御する。
特に、本実施形態は、予め設定された値を45度とすることにより、変調信号の周波数に対する位相遅れの感度の高いところで位相遅れが算出されるので、精度の高い蛍光緩和時間を算出することができる。
上記説明では、いずれも位相遅れと蛍光強度信号の値が予め設定された範囲に入るように調整されるが、蛍光強度信号の値が予め設定された範囲に入るか否かを判定することなく、位相遅れが予め設定された範囲に入るか否かのみを判定することもできる。
12 試料
22 レーザ光源部
22a レーザ光源
22b,24b,26b レンズ系
22c レーザドライバ
24,26 受光部
24a,26a 光電変換機
26c 遮蔽板
28 制御・信号処理部
30 データ処理部(コンピュータ)
30a 蛍光強度信号生成部
30b 蛍光強度算出部
30c 位相遅れ算出部
30d 信号制御部
30e 蛍光緩和時間算出部
32 管路
34 回収容器
40 変調信号制御部
40a 周波数可変発振器
40b パワースプリッタ
40c,40d,44a 増幅器
40e DC信号発生器
42 周波数変換部
42a 可変増幅器
42b IQミキサ
42c ローパスフィルタ
42d 90度位相シフタ
42e,42f ミキサ
44 AD変換部
44b AD変換器
Claims (8)
- レーザ光の照射を受けた測定対象物が発する蛍光を受光することにより得られる蛍光信号の信号処理を行う蛍光検出装置であって、
測定対象物に照射するレーザ光を強度変調して出射する光源部と、
レーザ光の照射された測定対象物から発する蛍光の蛍光信号を出力する受光部と、
前記光源部から出射するレーザ光を強度変調するための変調信号を生成する光源制御部と、
前記受光部で出力された蛍光信号から、前記変調信号に対する、測定対象物が発する蛍光の位相遅れを算出し、前記位相遅れを用いて測定対象物の蛍光の蛍光緩和時間を算出する処理部と、
前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数を制御する信号制御部と、を有することを特徴とする蛍光検出装置。 - 前記予め設定された値は、45度である、請求項1に記載の蛍光検出装置。
- 測定対象物は複数のサンプル粒子で構成され、前記サンプル粒子はレーザ光による測定場を一定速度で1つずつ断続的に通過し、
前記信号制御部は、前記サンプル粒子の前記測定場の通過の開始直後に、前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数の制御を開始し、前記サンプル粒子の前記レーザ光の測定場の通過終了前に、前記位相遅れの値が予め設定された値になる前記変調信号の周波数は見出され、見出された前記周波数の条件で得られる前記位相遅れと前記変調信号の周波数から前記蛍光緩和時間を算出する、請求項1または2に記載の蛍光検出装置。 - 前記測定対象物は、一定の容器に収容され、静止した状態で、レーザ光の照射を受け、
前記信号制御部は、前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数の制御を行って、前記制御が整定したときの前記位相遅れと前記変調信号の周波数から前記蛍光緩和時間を算出する、請求項1または2に記載の蛍光検出装置。 - レーザ光の照射を受けた測定対象物が発する蛍光を受光することにより得られる蛍光信号の信号処理を行う蛍光検出方法であって、
レーザ光源部から出射するレーザ光を強度変調するための変調信号を生成し、前記変調信号を用いてレーザ光を変調するステップと、
前記レーザ光の照射された測定対象物から発する蛍光の蛍光信号を取得するステップと、
前記蛍光信号から、前記変調信号に対する蛍光の位相遅れを算出するステップと、
前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数を制御するステップと、
前記制御が整定したときの前記変調信号の周波数の条件で得られる位相遅れを用いて、測定対象物の発する蛍光の蛍光緩和時間を算出するステップと、を有することを特徴とする蛍光検出方法。 - 前記予め設定された値は、45度である、請求項5に記載の蛍光検出方法。
- 測定対象物は複数のサンプル粒子で構成され、このサンプル粒子はレーザ光による測定場を一定速度で1つずつ断続的に通過し、
前記サンプル粒子のレーザ光の測定場の通過の開始直後に、前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数の制御を開始し、前記サンプル粒子の前記レーザ光の測定場の通過終了前に、前記位相遅れの値が予め設定された値になる前記変調信号の周波数は見出され、見出された前記周波数の条件で得られる前記位相遅れと前記変調信号の周波数から前記蛍光緩和時間を算出する、請求項5または6に記載の蛍光検出方法。 - 前記測定対象物は、一定の容器に収容され、静止した状態で、レーザ光の照射を受け、
前記位相遅れの値が予め設定された値に近づくように、前記変調信号の周波数の制御を行って、前記制御が整定したときの前記位相遅れと前記変調信号の周波数から前記蛍光緩和時間を算出する、請求項5または6に記載の蛍光検出方法。
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US10324019B2 (en) * | 2016-03-17 | 2019-06-18 | Becton, Dickinson And Company | Cell sorting using a high throughput fluorescence flow cytometer |
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