JPH06500636A - Optical method for selectively detecting specific substances in chemical, biochemical, and biological measurement samples - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Optical technology that selectively detects specific substances in chemical, biochemical, and biological measurement samples. Method This invention uses a diffraction grating coupler as defined in the first part of claim 1. By measuring the change in effective refractive index, specific substances in the measurement sample can be selectively detected. Regarding how to

In order to excite the mode introduced into the leading wave body, it is possible to perform coupling using a diffraction grating. This is a well-known method. Using diffraction gratings as integrated optical sensors can help improve sensor experiments. i.e. for example to incorporate a specific substance into a chemically sensitive waveguide (lattice ) 1\ effective refractive index of the area changes. This change in effective refractive index can be sampled in various ways. will be processed. Wo 8607149 specification (U.S. Patent No. 4815843 specification) A pair of these possibilities are disclosed, e.g. Therefore, it is possible to measure the intensity of diffraction orders that are not incident with a photodiode. It has been proposed. This type of measurement has a narrow dynamic range and requires a moving mechanism to adjust the angle of incidence. It is also sensitive to variations in light intensity caused by the light source.

Furthermore, Wo 8810418 specification (European Patent No. 0321523 specification) and According to specification W09008318 (specification of European Patent No. 0404900) For example, it is also known to illuminate a diffraction grating with light from various directions.

Magazine 5 Ensors and Actuators Bl (1990), 5 85-588 and magazine SP [E Vol. 1141 (1989), 192 -200 describes a grating coupler sensor based on capture by a diffraction grating. In that case, the excitation of the mode is performed at the end face, and the manufacturing method is ers 8 (f983), 537-539 (tapered A non-uniform diffraction grating (with a modulating waveform) is used. Therefore, import and take The ejecting is performed by two different and independent coupling members. Intake at the edge Requires flat optical surfaces that cannot actually be manufactured in mass production. The diffraction grating coupling member is Disposable 5 sensor chip ), it must be possible to manufacture it at a very low cost due to manufacturing technology. So As a result, the surface treatment of the end face of the diffraction grating coupling member is not a problem. Furthermore, quoted above The publications always mention that a gel layer is used as a microporous waveguide film. used. Microporous layers absorb moisture and cause sensor signal drift Therefore, due to its structure, it is not suitable for obtaining a very high refractive index and high sensitivity.

According to WO8607149, mode excitation or light capture is unique. It can also be carried out through a vertical (second) diffraction grating, and the modification is more reliable compared to capture at the end face. known to be good. This double grating device is not a purely periodic structure.

This is because attaching two independent gratings is done in separate steps. It is et al. Therefore, for importing and retrieving, there are two separate or similar Use a connecting member. Even in this case, the excitation of the mode requires a second diffraction grating, i.e. It is necessary to accurately position the radiation grating with respect to the incident light beam. Therefore, J : The deviation of the double diffraction grating device is not allowed. (i.e., a single broadly uniform diffraction grating, or a single diffractive grating structure). Furthermore, in a purely periodic grating structure, the incident light Precise positioning relative to the beam is not required. European Patent No. 0455067 As mentioned in the book, multi-diffractive grating structures are again complex grating structures. Become a body. According to EP 0 455 067, a multi-diffractive grating structure After a coherent light beam is incident on this multi-diffractive grating structure, The light beam diffracted by the multi-diffractive grating structure is emitted by mode excitation. The result is a diffracted light beam that is angularly separated by the light beam. It is stipulated that the

As defined in claim 1, this invention does not use a movable mechanism, Solving the problem of providing a method that can sample effective refractive index changes There is a particular thing.

Using a diffraction grating that has a uniform weak coupling over a wide range with an incident planar optical electromagnetic field (The incident focused wave leaves the grating as a diffracted divergent wave, and if the coupling is weak, the introduced mode leaves the grating almost as a plane wave) and has a bright light spot. Diffracted light uses position-sensitive detectors in electromagnetic fields, especially on moving mechanisms and expensive surfaces. dependence on processing and light intensity fluctuations can be eliminated.

Below, this invention will be explained in more detail based on the drawings.

FIG. 1 shows a measuring device for carrying out the method described above.

FIG. 2 shows a measuring device with - I-nones and one diaphragm.

Figure 3 shows a measuring device with a compact structure due to multiple specular reflections in the optical path. show.

FIG. 4 shows a measuring device for biochemical applications using cells.

Figure 5 shows that acquisition is possible in two propagation directions, allowing absolute measurement of the effective refractive index. An expanded measuring device is shown.

According to FIG. 1, the grating coupler 1o includes a substrate 2 (for example, a synthetic resin or glass A porous or non-porous waveguide is connected to this substrate. film 3 (for example, ZrO, Nb20B, Tl0z, TazOs, or For example, the diffraction grating 4 is made of other high refractive index material with a refractive index of 2.0 or more. Ru. In this case, the film 3 itself is selected to be sensitive to chemicals, but Alternatively, a chemically sensitive substance 14 is attached to this film (see Figure 2), and a diffraction grating is attached. 4 is disposed at the upper or lower interface of the waveguide film 3. High refractive index and non-porous To manufacture the waveguide film 3, vacuum deposition method is mainly used.

A light beam 5 from a monochromatic light source (not shown) is directed toward the diffraction grating 4, but this beam is It is taken in through the diffraction grating 4 and taken out through the same diffraction grating 4. In this case, the exit angle α and the entrance/exit equation, N=Sjnα+±j(λ/A) given by. Here, N: effective refractive index of the introduced mode, α1: The angle of incidence or the angle of exit,! ! : The attached diffraction order C+1 is the incident equation, -f is the exit equation ), λ: wavelength, Δ: grating period. Appropriate polarization for light beam 5 can be selected to excite the TE mode or TM mode in a manner known per se. incident The angle or exit angle is between the resonant incidence angle or resonant exit angle and the autocollimation angle. This is the difference.

A 5iOs-Ti02 waveguide 1 and a diffraction grating 4 having, for example, 1200 lines/mm. Use diffraction orders! =±1. ±2. Input/output is performed with respect to ±3. i' = Incoming light with diffraction order of +1/-1 and light emitted with diffraction order of f = +2/-2 be detected sensitively to the position, or be detected with the incident light at the diffraction order of 1 = +2/-2. It is advantageous to detect the light emitted at the diffraction order of ff1 = +1/-1 in a sensitive manner to the position. Ru.

In order to eliminate a moving mechanism when taking in light, the planar optical electromagnetic wave 6 is diffracted at the incident surface. a grating 4, in which case the focal point of said planar optoelectromagnetic field 6 is preferably directed directly onto the grating 4; It should be above the child structure. This may vary due to the effective refractive index or sensor experiment. However, if the waveguide structure changes due to manufacturing reasons or the measurement sample 13 (e.g. blood Even if the refractive index of the plasma (plasma) changes from measurement to measurement, modes are always excited with a constant geometrical relationship. let The grating coupler 10 has a planar shape that can be adjusted according to the angle with a small opening angle. Illumination can also be performed using a photoelectromagnetic field 6 of 1, and the position of the illuminated grid location does not move.

This ensures a sufficiently high light intensity for the introduced mode 16. Planar photoelectromagnetic Adjusting the field 6 to the angle can be done, for example, by using a Philips video disc. This can be done using electromagnetic mirrors and lenses like those used in players. A lens is an electromagnetic mirror in which the focal point of an incident planar optical electromagnetic field is routed through the lens. disposed between the electromagnetic mirror and the grating coupler 10 so as to form an image on the folded grating 4; ing. Due to the action of the lens, the rotation of the mirror causes a planar photoelectromagnetic beam to be focused on the diffraction grating 4. It changes the field according to the angle, but it is not possible to move the position of the illuminated grid point. It doesn't matter.

Since mode 16 is extracted by weak coupling, the introduced mode 16 is the coupling length taken over a longer interval, also referred to as Therefore, it was taken out The optical electromagnetic field 17.20 is approximately a plane wave (see Figures 2 and 3). taken out These optical electromagnetic fields 17.20 are compared to the directly diffracted light t′m fields 8,9.11. , the degree of bond length is necessarily shifted laterally. The incident planar optical electromagnetic field 6 is Since the directly diffracted optical electromagnetic field 8.9.11 also appears in a planar manner, , the optical electromagnetic field 8, 9. which is directly diffracted from the optical electromagnetic field 17.20 extracted by the weak coupling. I This ensures that f is separated spatially and according to spatial frequency. weak Coupling is achieved, for example, by keeping the modulation of the diffraction grating 4 small.

For example, according to FIG. It is within the range of the optical electromagnetic field 9 of the diffraction order emerging from the beam. On top of the planar photoelectromagnetic field 9 The optical electromagnetic field 17 generated by extracting the mode 16 introduced by the diffraction grating 4 overlaps. exists, and has an exit angle α1 given by the entrance and exit equations, see Figure 1. ), forming a bright light spot 12 on the position sensitive detector 7. introduced mode When the effective refractive index of the lens 16 changes depending on the sensor experiment, the exit angle α 1 also changes, and the bright light spot 12 moves with the photoelectromagnetic field 9. light spot 12 Said movement of can be detected with a position sensitive detector 7. This kind of detection took out It is unrelated to fluctuations in the light intensity of the optical electromagnetic field 17 and the directly diffracted optical electromagnetic field 9. for example , using a position-sensitive detector such as Hamamatsu Photox's detector 53979. Then, the intensity of the light spot 12 outside the position also changes with the mode 16 introduced thereby. The intensity of can also be measured indirectly.

According to FIG. 2, between the diffraction grating 4 and the position-sensitive detector 7, there is a The convex lens 1 is arranged such that the optical electromagnetic field 17 emitted by the 8 is advantageous. Therefore, the sensitive detector 7 is in the focal plane of the lens I8. That will happen. The directly diffracted optical electromagnetic field 9 is emitted in a planar shape, so this optical electromagnetic field is This appears as a light distribution that is not focused on the focal plane of the lens 18. And for that Obstructing the measurement of the light spot 120 position a that is focused and generated from the emitted optical electromagnetic field 17 There isn't.

It is often advantageous to use an aperture 19 between the grating 4 and the position-sensitive detector 7. Ru. Usually, this diaphragm 19 is placed between the diffraction grating 4 and the lens I8, preferably by a grating coupling. The optical electromagnetic field 17 is placed close to the instrument 10 and is directly diffracted by weak coupling. The optical electromagnetic field 9 is spatially separated. This is because the emitted optical electromagnetic field 17 is a surface This is because the coupling length is always shifted laterally for the optical electromagnetic field 9 emitted in Ru. Therefore, by using the aperture 19, the extracted photoelectromagnetic field 17 can be reduced. It is achieved that the optical electromagnetic field 17 is at least partially blocked and the extracted optical electromagnetic field 17 is not disturbed.

Optical electromagnetic field directly transmitted or reflected through the position sensitive detector 7 8.　 If installed in 1L, directly transmitted or reflected 1. Optical electromagnetic $8.11 Since the position-sensitive detector 7 is not strongly illuminated by the diaphragm 1 (see Fig. 3), 9 is highly recommended.

It is advantageous to at least partially protect the light beam path from turbulence and ambient temperature changes. , this suppresses the noise caused by the turbulence at the location of the light spot 12 and therefore The resolution of the position is improved. This involves protecting the optical electromagnetic field from its surroundings and allowing it to propagate For example, use a circular tube (e.g. made of glass or plastic) or a transparent object. use Very low temperature and thermal expansion coefficients, such as quartz or cello It is advantageous to use a transparent body made of silica.

According to Figure 3, the elongation of the measuring device is achieved by specularly reflecting the light beam path. Can be reduced. For example, a mirror 22 may be placed on the surface of the main body 21, which has a small temperature coefficient and coefficient of thermal expansion. The attached and extracted optical electromagnetic field 17.20 is reflected one or more times. After that, the body is aligned with a grating coupler 10 so as to output the radiation to a position sensitive detector 7. and the detector 7, which is sensitive to position. The incidence of this body in relation to the beam path Preferably, an anti-reflection film 23 is provided on the output surface and the output surface, but this main body also prevents turbulent flow. Protect the beam path against

The introduced mode 16 is caused by Bragg reflection during the period when the change in effective refractive index is being measured. It must be constructed with a chemical-sensitive waveguide and grating period to prevent radiation.

This means that, for example, the photoelectromagnetic field 17 that generates the bright light spots 12 passes through the diffraction grating 4 vertically. It is achieved by not going out. When retroreflection mode occurs, it causes disturbance.

For example, the retroreflection mode is also extracted as a nearly plane wave, and the second light A spot is formed on the position sensitive detector 7.

The measurement method according to the invention is of particular interest for biochemical analysis. As an example, Let us mention the detection of epidemiological reactions. According to FIG. 4, on the diffraction grating 4, in this case, There is an antibody or antigen layer corresponding to the chemically sensitive substance 14. antigen or A liquid measurement sample 13 for growing antibodies is injected into the cell 15, or by capillary action. Aspirate with. When two immune objects combine, a change occurs in the effective refractive index, causing a light spot 1 2 moves above a position sensitive detector 7. Reaction time controlled by diffusion It is advantageous to use cells with a depth of less than 500 μm in order to increase the length instead of (Pt+i1. Trans, R, Soe, Lond, 8316.143 -160 (1987)). This measurement principle can also be used for other unique binding partners. Can be used.

] The two measurement principles are “Compet Mountain on + 5say” (competitive analysis test ) or Sandwich Assay” You can also use it. Binding macromolecules or Synthetic resin (polystyrene or latex), high refractive index glass (TiOz, A sphere made of LiNb0*, glass) or gold@ (gold, titanium, aluminum) use. These things are explained in the literature “refraitive index 1ab”. It is also written as "el" (label for refractive index). active 1ndex 1abel” can be combined both reversibly and irreversibly. In addition to the immunobinding substance 14 and the substance to be tested, a third reagent is formed. example For example, the above “refractive 1ndex 1abel” is applied to the diffraction grating 4. It is located on the opposite wall of the cell, and it is also set in advance to go there after melting the liquid measurement sample. can. Other analytical tests can also be performed using the three reagents.

The method according to the invention generally involves the use of specific It can also be used to detect reactions that proceed with different substances. For example, culture medium When the enzyme immobilized on the waveguide film 3 performs conversion, a change in the refractive index occurs. Jiru. In this case, the culture medium forms a unique substance and the enzyme is a chemically sensitive substance. form quality 14. The catalytic action of the enzyme is caused by the adhesion to the surface of the waveguide, which is sensitive to chemicals. This will also result in the formation of undissolved products.

For example, if the substance sensitive to chemicals 14 is composed of a membrane, it may be caused by a specific substance. The reaction that progresses within or on the membrane depends on the distance between the membrane and the waveguide film 3 or this The structure or thickness of the membrane changes. This method represents an augmentation mechanism and should be verified. Small molecules result in large changes in effective refractive index.

When the cell 15 is provided in the grating coupler 10, the wall of the cell facing the diffraction grating 4 is To reduce turbulent reflections, use materials that absorb light or are constructed with materials that reflect as little as possible. It would be advantageous if this could be done. This includes the fully introduced mode 16 related to measurement. Since the introduced mode 16 is located under the measurement sample 13, the measurement sample 13 and the chemical agent It is possible to cross the edge of the measurement sample 13 in a closed line due to the material-sensitive waveguide l. do not have.

To improve the sensitivity of the grating coupler sensor, a low It is also advantageous to insert a layer 2' of refractive index (see FIG. 4). This low refractive index layer 2 ' can be formed into a pattern depending on the case. 112' microporous and low refractive index When a non-porous waveguide film 3 is coated on the surface, water is absorbed through the micropores of the low refractive index layer 2'. No absorption takes place.

The measurement structure proposed here can also be extended as follows, as shown in Figure 5. Wear. That is, using the second planar optical electromagnetic field 6', a mode in the opposite propagation direction to the mode 16 is detected. 16' is excited, and this mode 16' is extracted as a planar optical electromagnetic field 9' which is diffracted. Therefore, a bright light spot 12' is generated, and the effective refractive index of this second mode 16' is The change in is measured by a position-sensitive second detector 7' via the movement of the light spot 12'.

Two planar optical electromagnetic waves 6 and 6' can be applied to a diffraction grating simultaneously or by multiple lasing method. Occurs in 4. According to U.S. Pat. No. 4,952,056, via the resonant angle of incidence Calculate automatic collimation angles to excite motes in forward or backward directions. This allows the effective refractive index to be determined quantitatively. The incident angle and the exit angle are both The measuring device (see Fig. 1) shows the number of people Since the incident angle α1 is measured by determining the position of the light spot 12, the extended The effective refractive index can also be measured quantitatively using a similar measuring device. This means that For example, the grating coupler IO can be removed from the extended measuring device and placed above the diffraction grating 4. A chemical-sensitive substance 14 is incubated with the measurement sample 13, and then the effective refractive index is determined. To make measurements, it is possible to introduce the expanded measuring device again. For culture The change in effective refractive index can be measured. This is because the effective refractive index can be measured quantitatively. This is because that. Automatic angular collimation corresponds to light spots 12 and 12' in each case. can be determined from two positions on the position sensitive detectors 7 and 7'. Therefore, the lattice The slight re-installation angle error that occurs when attaching the combiner IO to the expanded measuring device is , actually does not affect the upper cylinder.

The method according to the invention can be used in a simple manner on multiple channels. Because, This is because this measurement method is a reflection method. This multi-channel use requires many gratings, grating stripes, or large two-dimensional gratings can be used. So , attach different chemically sensitive substances to different lattice regions. These chi One of the channels can also be used as a reference channel, for example.

If we use a waveguide l that has strong light absorption and is sensitive to chemicals, bright light spots can be seen in Figure 1. 12 corresponds to the dark spot 12#, and in the optical electromagnetic field 8.9.11 of the incident diffraction order, observed at the zeroth reflection diffraction order. The absorbing waveguide no longer absorbs the captured light. energy cannot be extracted and is dissipated in the absorbing waveguide. . At that time, this light is lost in diffraction orders that are not captured or emitted. As a result, dark spots 12' are formed in the photoelectromagnetic field 8, 9.11. Not light absorbing Unlike thin waveguides, strong coupling is advantageous here. The position sensitive detector 7 is It must be designed so that the position of the dark spot 12' can be recorded. This kind of record This can be done, for example, with an array of photodiodes.

Fig, 1 Fig. 3 Fig, 5

Claims (1)

[Claims] 1. The diffraction grating (4) acts as both an input grating and an output grating, allowing the chemical to The sensitive waveguide (1) is a chemically sensitive waveguide film (3) or a diffraction grating. a chemical-sensitive substance (14) covering the waveguide film (3) in the region of the child (4); The measurement sample (13) is located in the region of the diffraction grating (4) and the waveguide (1) is sensitive to chemicals. Area of light spots (8, 9, 11) of diffraction orders that are in contact with the detector and have not taken out the detector. and propagates through a chemical-sensitive waveguide (1) equipped with a diffraction grating (4). The change in the effective refractive index of the introduced mode (16) is measured for chemical, biochemical and In a method for selectively detecting a specific substance in a biological measurement sample (13), The folded grating (4) has at least one monochromatic planar photoelectromagnetic plate to confirm mode excitation. illuminated by field (6), with uniform modulation to ensure weak coupling, and directly refracted. Space from the optical electromagnetic field (17, 20) extracted from the planar optical electromagnetic field (8, 9, 11) The introduced mode (16) has a grating period such that it does not undergo plapp reflections during the measurement period, and is suitable for position-sensitive detection. The output device (7) generates a refracted planar photoelectromagnetic field (8,9,1) with bright light spots (12). 1) an optical electromagnetic field (17 , 20), and since it is a weak coupling, it becomes almost a plane wave, and therefore it is refracted. The introduced mode ( 16) becomes a closed line between the measurement sample (13) and the chemical-sensitive waveguide (1). A specific substance can be used as a chemical-sensitive conductor without crossing the edge of the measurement sample (13). by coupling on or in the wave body (1) or by chemically sensitive waveguides. said light produced by a reaction proceeding due to a specific substance on or in the body (1) that the movement of the bright light spot (12) is measured by a position sensitive detector (7); How to characterize it. 2. A position sensitive detector (7) detects the directly reflected or directly transmitted optical electromagnetic field. Written in the refracted planar optical electromagnetic field (9) that does not correspond to (8, 11) The method of claim 1, characterized in that: 3. The light beam path is at least partially protected from ambient disturbances using a covering element The method according to claim 1 or 2, characterized in that: 4. A non-porous high refractive index layer is used as the waveguide film (3). 4. A method according to any one of claims 1 to 3, characterized in that: 5. Claim 1, characterized in that the diffraction grating (4) has a single diffraction grating structure. The method according to any one of items 1 to 4. 6. The incident planar optical electromagnetic field (6) has a light intensity strong enough for the introduced mode (16). In order to ensure Any one of claims 1 to 5, characterized in that the angle can be readjusted as desired. Section method. 7. A lens is placed in the beam path between the diffraction grating (4) and the position-sensitive detector (7). Any one of claims 1 to 6, characterized in that (18) is provided. the method of. 8. A diaphragm ( 19) according to any one of claims 1 to 7, characterized in that: Method. 9. The elongation of the measuring device is kept low by specular reflection of the light beam path. 9. A method according to any one of claims 1 to 8, characterized in that: 10. A low refractive index layer is provided on the waveguide (1) between the substrate (2) and the waveguide film (3). (2') is provided in any one of claims 1 to 9. the method of. 11. To ensure mode excitation in the forward or backward direction, a diffraction grating (4 ) is illuminated with at least two planar photoelectromagnetic fields (6, 6′), and two position-sensitive Two optical electromagnetic fields (1 2, 12'), and from both positions of the optical electromagnetic field (12, 12'), Claims characterized in that each position corresponding to a dynamic collimation angle is measured. The method according to any one of items 1 to 10. 12. The chemical-sensitive waveguide (1) connects the chemical-sensitive waveguide film (3). , or sensitive to chemicals covering the waveguide film (3) at the diffraction grating (4). The measurement sample (13) has a chemical substance (14) at the diffraction grating (4). The light-year magnetic field (8, 9, 11), with a detector sensitive to chemicals equipped with a diffraction grating (4). of the effective refractive index of the introduced mode (16) propagating in the grating region of the waveguide (1). Measure changes to identify specific substances in chemical, biochemical, and biological measurement samples (13) In the selective detection method, the chemical-sensitive waveguide (1) is light-absorbing. In order to confirm the excitation of at least one mode, the diffraction grating (4) is Illumination with one monochromatic planar photoelectromagnetic field (6) and diffraction with dark spots (12'') A position-sensitive detector (7) is placed in the planar optical electromagnetic field (8, 9, 11). , by attaching a special substance on or inside the chemically sensitive waveguide (1), or propagated by a specific substance on or in the chemically sensitive waveguide (1). The movement of the dark spot (12'') due to the reaction is detected by a position-sensitive detector (7). A method characterized by measuring.