JP6676236B2 - Measuring chip, measuring device, and measuring method - Google Patents

Description

  The present invention relates to a measurement chip made of a photonic crystal, a measurement device in which the measurement chip is arranged, and a measurement method using the measurement chip.

  Conventionally, a biosensor using a photonic crystal has been proposed as a biosensor for performing gene analysis, clinical diagnosis, detection of harmful substances, and the like (for example, see Patent Document 1).

  The photonic crystal is made of a dielectric having a periodic structure in which a predetermined pattern (for example, a columnar structure) is periodically arranged. In Patent Document 1, measurement using a photonic crystal is performed as follows.

(1) A sample containing no test substance or the like is brought into contact with a photonic crystal.
(2) The photonic crystal is irradiated with light to obtain information on the optical characteristics of reflected light (peak wavelength and intensity of reflected light).
(3) The sample containing the test substance is brought into contact with the photonic crystal.
(4) After the sample containing the test substance is brought into contact, information on the optical characteristics of the reflected light is obtained in the same manner as in (2) above.
(5) The presence or absence and amount of the test substance contained in the sample are detected by comparing the optical characteristics of the reflected light in (4) with the optical characteristics in (2).

JP 2014-202574 A

  In a measurement method using a photonic crystal as disclosed in Patent Document 1, it is necessary to improve the sensitivity of a substance to be detected.

  An object of the present invention is to provide a measurement chip with higher sensitivity than before, a measurement device in which the measurement chip is arranged, and a measurement method using the measurement chip.

  The present invention is a measurement chip made of a dielectric material, wherein the dielectric material is a photonic crystal having a periodic structure in which a predetermined pattern is periodically arranged, and the photonic crystal partially has the periodic structure. It is characterized in that a specific pattern having an arrangement mode different from the arrangement is formed.

  A photonic crystal is a dielectric having a periodic structure in which patterns such as holes or columnar structures are periodically arranged (however, the dielectric material itself does not have a crystal structure at an atomic or molecular level). With this periodic structure, the photonic crystal has a property of reflecting light in a specific wavelength range (functions as a mirror that reflects light in a specific wavelength range). Here, the present invention provides a specific pattern having an arrangement mode different from the periodic arrangement on a part of the photonic crystal, so that the portion where the specific pattern is provided functions as a space sandwiched between mirrors. Let it. Accordingly, the unique pattern functions as a resonator that resonates light of a specific wavelength, and can emit only light of a specific wavelength at a very high SN ratio.

  When another substance (substance to be detected) is adsorbed around the measurement chip (for example, around the peculiar pattern), the resonance wavelength as a resonator changes due to a change in the surface refractive index. Therefore, the target substance can be detected with very high sensitivity by irradiating the measurement chip with light having a specific wavelength spectrum and measuring the change in the characteristics of the light emitted from the resonator. Note that the characteristics of light may be directly measured by a change in the wavelength of light emitted from the unique pattern.However, when light of a single wavelength is incident, the peak intensity of light depends on the presence or absence of the substance to be detected. It changes greatly. Therefore, the presence or absence of the substance to be detected can be determined or quantified by measuring the change in intensity. When measuring the intensity change, an advanced spectroscope or the like is not required, and a very inexpensive measuring device can be realized.

  It is preferable that the peculiar pattern has a structure in which a part of the periodic structure is omitted. Further, it is preferable that the peculiar pattern has a structure in which a pattern for a plurality of periods is omitted from the periodic structure.

  The structure in which the patterns for a plurality of cycles are omitted is, for example, a structure in which the patterns for a plurality of cycles are omitted in a one-dimensional shape (linear shape) in plan view, or a two-dimensional shape in a plan view. An example in which a pattern for a plurality of cycles is omitted is considered.

  Note that a group of photonic crystals including the above-described specific pattern can be further arranged in a plurality of arrays to form a measurement chip.

  Further, it is preferable that the dielectric be made of an acrylic resin, polyvinyl alcohol, polyvinyl chloride, a silicone resin, polystyrene, or TiO2, so as to use a material that is inexpensive and easy to manufacture.

  Note that by making the light to be resonated into a visible light region (for example, red light of 650 nm), the cost of the light source and the measuring unit can be reduced.

  According to the present invention, it is possible to provide a measurement chip with higher sensitivity than before, a measurement device in which the measurement chip is arranged, and a measurement method using the measurement chip.

FIG. 2 is a diagram illustrating a schematic configuration of a measurement device 15. FIG. 2 is a block diagram illustrating a configuration of a measurement device 15. FIG. 2 is a diagram illustrating a structure of a chip 1. FIG. 4 is a diagram illustrating a state of reflection when a laser beam is irradiated to the chip 1. FIG. 9 is a diagram showing a change in the intensity of light emitted from a unique pattern 12. It is a flowchart of an inspection method. It is a top view showing a modification of a peculiar pattern. It is a comparison figure by the difference of the number of periods of a peculiar pattern. It is a top view showing the structure of an array type chip.

  FIG. 1 is a diagram showing a schematic configuration of a measuring device 15 including a measuring chip of the present invention. FIG. 2 is a block diagram illustrating a configuration of the measuring device 15.

  As shown in FIG. 1, the measurement device 15 includes a chip (measurement chip) 1, a light emitting unit 10, a polarizing plate 20, a light receiving unit 30, a measuring unit 31, and a control unit (comparing unit) 32. The measurement unit 31 and the control unit 32 may be dedicated hardware, or may be realized by software installed in an information processing device such as a personal computer.

  The light emitting unit 10 is a light source that emits light having a specific wavelength, and is a light source that emits, for example, 650 nm visible laser light. The laser light is applied to the chip 1 via the polarizing plate 20.

  FIG. 3 is a diagram showing the structure of the chip 1. FIG. 3A is a perspective view, FIG. 3B is a plan view, and FIG. 3C is a partially enlarged cross-sectional view.

  The chip 1 is a plate-shaped member made of the dielectric 11. The dielectric 11 is made of, for example, acrylic resin, polyvinyl alcohol, polyvinyl chloride, silicone resin, polystyrene, TiO2, or the like. In this example, the dielectric 11 is made of polystyrene having a dielectric constant ε = about 2.4. Further, in this example, the dielectric 11 has a thin regular hexagonal flat plate shape in plan view. However, the shape of the dielectric 11 is not limited to the example shown in FIG. For example, the shape may be a square shape or a circular shape in plan view. Further, a shape having a certain thickness such as a cube or a rectangular parallelepiped may be used.

  A plurality of holes 13 having a circular shape in plan view are patterned in the dielectric 11. The hole 13 has, for example, an inner diameter φ of 150 to 200 nm and a height d of 100 to 200 nm. The holes 13 are periodically arranged at a pitch p = 300 nm. The dielectric 11 is a photonic crystal having such a surrounding structure. However, a photonic crystal refers to a dielectric having a periodic structure in which patterns such as holes or columnar structures are periodically arranged, and the dielectric material itself does not have a periodic structure at an atomic or molecular level.

  Such a photonic crystal is created by, for example, a nanoimprint method. The nano-imprint method is a method in which a template such as a metal in which a columnar structure is patterned is prepared, and the hole 13 is formed by transferring the pattern to the dielectric 11. As a result, a polymer resin can be used as the dielectric 11, and the chip 1 can be manufactured at a lower cost than when a semiconductor process using a Si substrate is used.

  The thus prepared photonic crystal is further impregnated with, for example, a ligand diluting solution, so that the analyte and the ligand to be adsorbed in the sample are mixed with the entire photonic crystal (or only the specific pattern). Be fixed. However, the present invention is not limited to this, and the ligand may be immobilized on the photonic crystal by another method using a silane coupling agent or the like.

  Note that the periodic structure is not limited to the example in which the patterns of the holes 13 shown in FIG. 3 are periodically arranged. For example, it is also possible to adopt a mode in which cylindrical or prismatic structures are periodically arranged on the main surface of the dielectric 11. In addition, by arranging the columnar structures three-dimensionally in a grid pattern, it is possible to form a three-dimensional periodic array.

  The photonic crystal has a characteristic of reflecting light in a specific wavelength range by periodically arranging the predetermined patterns as described above. For example, the structure in which the holes 13 shown in FIG. 3 are periodically arranged has a characteristic of reflecting red light in a specific wavelength band (for example, 620 to 680 nm) around about 650 nm.

  Here, at the center position of the dielectric 11, a peculiar pattern 12, which is a portion where the holes 13 are omitted (the holes 13 are not formed), is provided. That is, the peculiar pattern 12 is a part having an arrangement mode different from the periodic arrangement.

  The periodic structure formed by the holes 13 functions as a mirror that reflects light in a specific wavelength range (for example, 620 nm to 680 nm) as described above. The unique pattern 12 functions as a space surrounded by such a mirror. When light is introduced into the space surrounded by the mirror, the light is repeatedly reflected on the mirror, so that a specific wavelength in the specific wavelength range resonates and shows a high intensity peak at the specific wavelength. Will be.

  Thereby, the unique pattern 12 functions as a resonator (Fabry-Perot resonator) that resonates light of a specific wavelength. Therefore, when the chip 1 is irradiated with light, only light having a specific wavelength (for example, 650 nm) can be emitted from the unique pattern 12 at a very high SN ratio.

  FIG. 4 is a diagram showing a state in which the chip 1 is irradiated with a laser beam of 650 nm. 4A is a plan view of the chip 1, FIG. 4B is a diagram showing an intensity distribution of emitted light, and FIG. 4C is an image of the chip 1 taken with a fluorescence microscope. It is an image. Although FIG. 4 shows a structure in which a larger number of holes are formed than the chip 1 shown in FIG. 3 for the sake of explanation, it is functionally similar to the chip 1 shown in FIG. is there.

  As shown in these figures, it is understood that when the chip 1 is irradiated with light, high intensity light is emitted (high intensity emitted light is observed) at the location of the unique pattern 12.

  The measuring device 15 of the present embodiment irradiates light having a wavelength (for example, 650 nm) that resonates with the unique pattern 12 from the light emitting unit 10, receives light emitted from the unique pattern 12 by the light receiving unit 30, and The intensity of the light is measured. The intensity measured by the measuring unit 31 is input to the control unit 32 and recorded in a memory (not shown).

  When another substance (substance to be detected) is adsorbed on the dielectric 11, the surface refractive index changes and the resonance wavelength of the resonator changes. Further, the efficiency as a resonator also decreases. In this embodiment, since light of a single wavelength (650 nm) is emitted from the light emitting unit 10, the resonance wavelength changes, and when the efficiency as a resonator decreases, the intensity of light emitted from the unique pattern 12 increases. descend.

  In the chip 1 after being immersed in the sample (containing the substance to be detected (analyte) adsorbed on the ligand of the chip), the measuring device 15 again emits the light emitted from the specific pattern 12 by the light receiving unit 30. And the measuring unit 31 measures the intensity of the light. The control unit 32 compares the light intensity measured first and the light intensity after immersion in the sample. When the light intensity indicates a change equal to or greater than the threshold, the control unit 32 determines that the detection target substance is included. In this way, the measurement device 15 functions as a test device that tests for the presence or absence of a substance to be detected (for example, an antigen such as an influenza virus).

  Since the chip 1 resonates light having a specific wavelength (for example, 650 nm) by the unique pattern 12 as described above, a light source having a wide band such as white light can be used as the light source, for example. In this case, the presence or absence of the substance to be detected can also be inspected by observing a change in the peak wavelength or a change in the spectrum shape, instead of the light intensity. However, when observing a change in intensity using light of a single wavelength as a light source, it is not necessary to use an expensive spectroscope for observing a change in wavelength, so that the cost as a measuring device can be reduced. . In addition, the light source and the light to be resonated are not limited to visible light, but particularly when using visible light, since a relatively expensive light source or measurement unit such as infrared light or ultraviolet light is not used, It is possible to reduce the cost as a measuring device.

  Next, FIG. 5 is a diagram illustrating a change in the intensity of light emitted from the unique pattern 12. In the horizontal axis of the graph shown in the figure, the item described as “bare” indicates a reference state in which nothing is adsorbed on the chip 1. The numerical values on the vertical axis are standardized based on the light intensity in the reference state.

  The description of “c1” is an item indicating the light intensity after the polycation is adsorbed on the chip 1. The description of “a1” is an item indicating the light intensity after the polyanion is further adsorbed on the chip 1. The description of “c2” is an item indicating the light intensity after the polycation is further adsorbed to the chip 1 thereafter. Hereinafter, the light intensity after each substance is repeatedly adsorbed is shown as the numerical value on the horizontal axis of the numerical value increases.

  As shown in FIG. 5, when a certain amount of substance is adsorbed on the surface of the dielectric 11, the intensity of light emitted from the unique pattern 12 is significantly reduced. For example, in FIG. 5, the intensity of light is significantly reduced from a1 to c2 (or c2 to a2). Therefore, by measuring the intensity of the reference, measuring the intensity after immersion in the sample, and comparing these light intensities, it is possible to detect the presence or absence of the substance to be detected.

  FIG. 6 is a flowchart of the measuring method. The measuring device 15 first measures the intensity of the reference (s11). The reference is, for example, a state after the chip 1 is washed with pure water or the like and dried.

  As shown in FIG. 1, the measuring device 15 is configured such that the chip 1 is installed at a predetermined place and has a predetermined angle (for example, 6 °) with respect to a direction parallel to the main surface of the chip 1. The laser light of the light emitting unit 10 is irradiated from the direction. In this example, the main surface of the chip 1 is irradiated with the laser light. However, the laser light may be guided from the end surface of the chip 1. However, when the laser light is directly applied to the unique pattern 12 of the chip 1, a coupling device for guiding the laser light is not required, so that a less expensive measuring device can be provided.

  The reference intensity measured as described above is recorded in the internal memory (not shown) of the control unit 32.

  Thereafter, the chip 1 is immersed in a sample containing a substance to be inspected (s12), washed with pure water or the like (s13), and dried (s14).

  Then, the measuring device 15 irradiates the chip 1 in a state after the sample comes into contact with the laser light, and measures the intensity of light emitted from the unique pattern 12 (s15).

  After that, the control unit 32 compares the intensity of the reference recorded in the memory with the intensity of the light after the sample is in contact with the reference. When the change in the intensity has changed by a predetermined threshold or more (for example, by 20% or more), the control unit 32 determines that the substance to be detected has been detected. Alternatively, the control unit 32 quantifies the substance to be detected according to the degree of change in the intensity.

  In this way, the measuring device 15 can detect the presence or absence of the substance to be detected with high sensitivity.

  In the above-described embodiment, as an example of the peculiar pattern 12, an example in which the hole 13 is omitted at only one place is shown. However, various modifications of the peculiar pattern can be considered.

  For example, in the chip 1A of FIG. 7A, some of the holes 13A and 13B are shifted from predetermined positions (in this example, the holes 13 are shifted to the left and the holes 13 are shifted to the right. As a result, a unique pattern 12A having an arrangement different from that of the periodic arrangement is formed.

  Further, as shown in FIG. 7B, the chip 1B has two places where the holes 13 are not formed. In this example, two unique patterns 12L and 12R are formed with the hole 13 formed near the center therebetween.

  FIGS. 7C and 7D are peculiar patterns having a structure in which patterns for a plurality of periods are omitted. The peculiar pattern 12C in the chip 1C in FIG. 7C has a structure in which the holes 13 are omitted in a one-dimensional manner (in a horizontal straight line) for three periods from the center position in plan view. The peculiar pattern 12D in the chip 1D of FIG. 7D has a structure in which holes 13 for three periods from the center position are omitted two-dimensionally in plan view.

  FIG. 8 is a comparison diagram based on the difference in the number of periods of the unique pattern. The example of FIG. 8A is an image obtained by photographing the chip 1 in which the hole 13 is omitted at only one place with a fluorescence microscope. The example in FIG. 8B is an image obtained by photographing a chip in which holes 13 for two cycles are omitted in plan view with a fluorescence microscope. The example in FIG. 8C is an image obtained by photographing a chip in which holes 13 for three cycles are omitted in a plan view with a fluorescence microscope. FIG. 8D is an image obtained by photographing the chip in which the holes 13 for four cycles are omitted in plan view with a fluorescence microscope, and FIG. It is the image which image | photographed the chip | tip omitted by the fluorescence microscope.

  From these images, the chip without the holes 13 for two cycles shown in FIG. 8B or the chip 1D without the holes 13 for three cycles shown in FIG. It can be seen that

  Therefore, a chip having higher sensitivity can be obtained by using a peculiar pattern in which a pattern for a plurality of cycles is omitted, in particular, a peculiar pattern in which a pattern for two or three cycles is omitted two-dimensionally. Also, as shown in FIGS. 8D and 8E, when the number of cycles is excessively increased, the intensity is conversely reduced, and there is a possibility that an optimum number of cycles corresponding to the wavelength may exist. The comparison made clear.

  Next, FIG. 9 is a plan view showing the structure of the array type chip. As shown in FIG. 9, the chip 100 is an array type chip in which a plurality of the chips 1 shown in FIG. 3 are arranged in an array. Since the chip 100 is of an array type, it is possible to realize higher intensity light at a place where the phases of the light radiated from the unique pattern 12 in each chip 1 are aligned, thereby realizing a chip with higher sensitivity. can do.

  In the present embodiment, an example in which visible light of 650 nm is resonated has been described. However, the photonic crystal can generate any electromagnetic wave by changing the dielectric constant, the shape and the arrangement of the pattern, and the like. It is also possible to resonate.

  Further, in the chip of the present embodiment, an example in which the holes 13 (predetermined patterns) are periodically arranged in a two-dimensional manner has been described, but a three-dimensional periodic arrangement is also possible. In this case, it is desirable that the peculiar pattern is also a peculiar pattern having a structure in which a pattern for a plurality of periods is omitted in a three-dimensional manner.

1,100 chip 10 light emitting unit 11 dielectrics 12, 12A, 12C, 12D, 12L, 12R specific patterns 13, 13A, 13B holes 15 measuring device 20 polarizing plate 30 light receiving unit 31 measuring unit 32 ... Control unit

Claims (5)

A measurement chip made of a dielectric,
The dielectric is made of acrylic resin, polyvinyl alcohol, polyvinyl chloride, silicone resin, polystyrene, or TiO ₂ , and has a predetermined pattern in which holes or columnar structures having a diameter of 150 nm to 200 nm and a height of 100 to 200 nm have a pitch of 300 nm and a periodicity. It is a photonic crystal that has an arranged periodic structure and reflects light having a wavelength of 620 to 680 nm ,
The photonic crystal has, in part, a peculiar pattern having an arrangement mode different from the periodic arrangement,
It said specific pattern, said one of the periodic structure, have a pattern of a planar view in two dimensions three periods is omitted structure, measurement chip that have a characteristic for resonating visible light of wavelength 650nm . The measurement chip according to claim 1,
A measurement chip which is an array type chip in which a plurality of photonic crystals including the specific pattern are arranged in an array. A measuring device on which the measuring chip according to claim 1 or 2 is arranged,
A light source that irradiates the specific pattern with light having a wavelength of 650 nm ;
A measuring unit for measuring the intensity of light emitted from the unique pattern,
A measuring device provided with. The measuring device according to claim 3 , wherein
The intensity of light measured by the measurement unit, before contacting the sample containing the substance to be detected with the measurement chip, and after contacting the sample containing the substance to be detected with the measurement chip And a measuring device provided with a comparing unit for comparing with. A measuring method using the measuring chip according to claim 1 or 2 ,
A first measurement step of irradiating the measurement chip with light and measuring the intensity of light emitted from the unique pattern,
A sample containing a substance to be detected is brought into contact with the measurement chip,
After contacting the sample containing the substance to be detected, a second measurement step of measuring the intensity of light emitted from the unique pattern,
A comparing step of comparing the intensity measured in the first measuring step with the intensity measured in the second measuring step;
Measurement method with

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