JP2015175621A - State holding method of sensor, and sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable rapid measurement by reducing the time until the oscillatory frequency becomes stable.SOLUTION: The sensor 1 includes a quartz oscillator 5 that has a sensing region to which a detection object in a sample solution adheres and whose resonance frequency is changed by the adhesion of the detection object. The sensing region including a sensitive film 10 formed on the excitation electrode 8a on one side of a quartz piece 7 of the quartz oscillator is dipped in a liquid 23 such as a buffer solution used for preparation of a sample solution to seal a vessel 24.

Description

  The present invention relates to a sensor for detecting a substance contained in a liquid and a method for maintaining the state of the sensor.

In recent years, as a sensor for detecting a very small amount of substance in liquid, the resonance frequency is changed by immersing a quartz vibrator, which is a piezoelectric vibrator, in the liquid and attaching the substance to the electrode surface of the crystal vibrator. Thus, a QCM (Quartz Crystal Microbalance) sensor that detects a trace amount of substance is used (for example, see Patent Documents 1 and 2). This QCM sensor can detect a change in mass of a substance on the order of 1 ng / cm ² .

JP 2008-102118 A Japanese Patent No. 4792098

  However, as described in Patent Documents 1 and 2, in the QCM sensor, the oscillation frequency is not stable at the initial stage of measurement. Therefore, the measurement cannot be started until the oscillation frequency is stabilized. I need time. Furthermore, even with QCM sensors having the same oscillation frequency, there is an individual difference in the time until the oscillation frequency is stabilized, so the waiting time until the start of measurement varies.

  As described above, the conventional QCM sensor has a problem that a waiting time until the start of measurement is necessary and the waiting time is varied, so that quick measurement cannot be performed.

  The present invention has been made in view of the above points, and it is an object of the present invention to shorten the time until the oscillation frequency is stabilized and to perform quick measurement.

  In order to achieve the above object, the inventors of the present invention have made extensive studies, and as a result, the sensor sensing region is pre-wet in a liquid state before measurement, so that the oscillation frequency is measured. As a result, the present invention has been completed.

  That is, the present invention is a method for maintaining a state of a sensor having a sensing region to which a detection target in a sample solution adheres, and including a piezoelectric vibrator whose resonance frequency changes due to the attachment of the detection target. Is kept wet with a liquid.

  In a preferred embodiment of the sensor state holding method of the present invention, the piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece, and the sensing region is the two main surfaces. A sensing film formed on the excitation electrode on at least one of the main surfaces, and the sensing region is held in a state immersed in the liquid.

  In another embodiment of the sensor state holding method of the present invention, the piezoelectric vibrator is a crystal vibrator in which excitation electrodes are respectively formed on both main surfaces of a crystal vibrating piece, and the sensing region is the two main faces. It includes a sensitive film formed on the excitation electrode on at least one main surface of the surface, and holds the sensing region in contact with the moisturizing body that has absorbed the liquid.

  In still another embodiment of the sensor state holding method of the present invention, the liquid is a buffer used for preparing the sample solution.

  In a preferred embodiment of the sensor state maintaining method of the present invention, the liquid is physiological saline or artificial sweat.

  In another embodiment of the sensor state holding method of the present invention, the sensor is shipped as a frozen product.

  According to the sensor state holding method of the present invention, the sensing region of the piezoelectric vibrator whose resonance frequency changes due to the detection target in the sample solution adhering to the sensing region is kept wet with the liquid. Therefore, the sensing area can be sufficiently familiar with the liquid by using the transport period during which the sensor is transported, and the user can detect the detection target in the sample solution using the sensor and the concentration thereof. Is measured, the oscillation frequency of the sensor is stabilized earlier than in the conventional example, and the waiting time until the start of measurement can be shortened. In addition, the sensor sensing area can be fully adapted to the liquid by using the transport period during which the sensor is shipped from the manufacturer and transported to the user, so that variations in waiting time due to individual differences in the sensor are also absorbed. be able to.

  Further, the sensing region includes a sensitive film formed on at least one excitation electrode of both excitation electrodes respectively formed on both main surfaces of the crystal vibrating piece constituting the crystal resonator, and by this sensitive film, The detection target in the sample solution can be attached.

  The sensing region may be in a wet state by being immersed in a liquid, or may be in a wet state by being in contact with a moisture retaining body that has absorbed the liquid.

  The liquid that wets the sensing area is preferably a buffer used in the preparation of the sample solution. Thus, by allowing the sensing region to be used in the buffer solution used for preparing the sample solution, the oscillation frequency of the sensor can be stabilized earlier, and the waiting time until the start of measurement can be further shortened.

  In addition, when the period from the shipment of the sensor by the manufacturer to the use of the sensor by the user is long, the liquid is a liquid that corrodes the electrodes of the piezoelectric vibrator, etc. by shipping as a refrigerated product. Even if it exists, corrosion of the electrode of a piezoelectric vibrator, etc. can be suppressed by maintaining at a low freezing temperature.

  The sensor of the present invention is a sensor including a piezoelectric vibrator, and the piezoelectric vibrator has a sensing region to which a detection target in a sample solution adheres, and a resonance frequency changes due to the attachment of the detection target. And holding means for holding the sensing region wet with a liquid.

  In a preferred embodiment of the sensor of the present invention, the piezoelectric vibrator is a crystal vibrator in which excitation electrodes are respectively formed on both main surfaces of the crystal vibrating piece, and the sensing region is at least one of the two main surfaces. It includes a sensitive film formed on the excitation electrode on the main surface, and the holding means has a container for enclosing at least the sensing region and the liquid immersed in the sensing region.

  The container is not particularly limited as long as it can enclose at least the sensing region of the sensor and the liquid. However, depending on the sensitive film, light may cause a decomposition reaction or the like, and thus has a light-shielding property to protect the sensitive film. A container is preferred.

  In another embodiment of the sensor of the present invention, the piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece, and the sensing region is at least one of the two main surfaces. The holding means has a moisturizing body that absorbs the liquid, and the moisturizing body is in contact with the sensing region.

  In still another embodiment of the sensor of the present invention, the liquid is a buffer used for preparing the sample solution.

  In another embodiment of the sensor of the present invention, the liquid is physiological saline or artificial sweat.

  In another embodiment of the sensor of the present invention, the sensor is shipped as a frozen product.

  According to the sensor of the present invention, the sensor includes a holding unit that holds the sensing region of the piezoelectric vibrator whose resonance frequency changes when the detection target in the sample solution is attached to the sensing region in a wet state with a liquid. Therefore, the sensing area can be sufficiently infiltrated with the liquid using the period during which the sensor is transported, etc., and the user can detect the concentration of the detection target in the sample solution using the sensor. When measuring the above, the oscillation frequency of the sensor is stabilized earlier than in the conventional example, and the waiting time until the measurement is started can be shortened. In addition, the sensor sensing area can be fully adapted to the liquid by using the transport period during which the sensor is shipped from the manufacturer and transported to the user, so that variations in waiting time due to individual differences in the sensor are also absorbed. be able to.

  Further, the sensing region includes a sensitive film formed on at least one excitation electrode of both excitation electrodes respectively formed on both main surfaces of the crystal vibrating piece constituting the crystal resonator, and by this sensitive film, The detection target in the sample solution can be attached.

  The holding means for holding the sensing area wet with a liquid may include a container in which at least the sensing area and the liquid in which the sensing area is immersed are sealed, or moisturizing that has absorbed the liquid. It may have a body and the moisturizing body may be brought into contact with the sensing region.

  The liquid that wets the sensing area is preferably a buffer used in the preparation of the sample solution. In this way, by adapting the sensing region to the buffer solution used for the preparation of the sample solution, the oscillation frequency of the sensor is stabilized earlier, and the waiting time until the start of measurement can be further shortened.

  In addition, when the period from the shipment of the sensor by the manufacturer to the use of the sensor by the user is long, the liquid is shipped as a product requiring refrigeration. However, corrosion of the electrodes of the piezoelectric vibrator can be suppressed by maintaining the low freezing temperature.

  According to the present invention, the sensing region of the piezoelectric vibrator whose resonance frequency changes due to the detection target in the sample solution adhering to the sensing region is maintained in a wet state with the liquid. When the user detects the detection target in the sample solution by using the sensor and measures its mass, etc. The oscillation frequency is stabilized earlier than the conventional example, and the waiting time until the start of measurement can be shortened. In addition, since a sufficient period during which the sensing area of the sensor can be adapted to the liquid can be ensured, variations in waiting time due to individual differences among sensors can be absorbed.

FIG. 1 is a view showing a QCM sensor according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a measurement system using the QCM sensor of FIG. FIG. 3 is a cross-sectional view showing a method for maintaining the state of the QCM sensor of FIG. FIG. 4 is a plan view of a QCM sensor according to another embodiment of the present invention. FIG. 5 is a cross-sectional view showing a method for maintaining the state of the QCM sensor of FIG. FIG. 6 is a diagram illustrating a method for maintaining a state of a QCM sensor according to another embodiment of the present invention. FIG. 7 is a view showing a QCM sensor according to another embodiment of the present invention. It is sectional drawing which shows the state holding method of the QCM sensor of FIG. It is a figure which shows the other state holding | maintenance method of the QCM sensor of FIG. It is a figure which shows the QCM sensor which concerns on other embodiment of this invention.

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B show a sensor according to an embodiment of the present invention. FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. .

  The sensor of this embodiment is a QCM sensor 1 including a crystal resonator 5 that is a piezoelectric resonator as a sensor element. The QCM sensor 1 includes a package 4 having a body 2 and a pair of legs 3, and an AT-cut crystal resonator 5 is incorporated in the body 2 of the package 4.

The package 4 of this embodiment basically has a laminated structure having a lower layer 4a, an intermediate layer 4b, and an upper layer 4c. For example, the package 4 is formed by firing laminated ceramic sheets. A circular through hole is formed in each of the upper layer 4c and the intermediate layer 4b on the body 2 side, and an accommodation recess 6 for fitting the crystal resonator 5 is formed. The opening diameter of the upper layer 4 c portion of the storage recess 6 is larger than the opening diameter of the intermediate layer 4 b portion, and a step portion that supports the peripheral portion of the crystal resonator 5 is formed in the storage recess 6.

  The crystal unit 5 includes a crystal piece 7 that is a crystal resonator element formed in a circular shape. Excitation electrodes 8a and 9a are circular in the center of both the front and back surfaces of the crystal piece 7, respectively. Is formed. Extraction electrodes 8b and 9b are formed from the excitation electrodes 8a and 9a toward the outer peripheral direction of the crystal piece 7 so as to be opposite to each other. The lead electrode 8b on the front surface side of the crystal piece 7 wraps around the back surface side as shown in FIG. These electrodes 8a, 9a; 8b, 9b are formed of, for example, a laminated film of chromium (Cr) / gold (Au) or Ti (titanium) / Au (gold). The electrode material is not limited to these metals, and nickel (Ni) / silver (Ag) or other metals may be used.

  On the excitation electrode 8a on the surface side of the crystal piece 7, a sensitive film 10 is formed on which a specific substance to be detected in the sample solution adheres by adsorption or the like.

  On the upper surface of the stepped portion of the housing recess 6 of the package 4, connection electrodes 11 and 12 are formed so as to correspond to the extraction electrodes 8 b and 9 b of the crystal piece 7, and the crystal piece 7 is connected to these connection electrodes 11 and 12. The extraction electrodes 8b and 9b are connected via a conductive adhesive 13 such as an epoxy resin. A resin other than an epoxy resin may be used as the conductive adhesive.

  The connection electrodes 11 and 12 are connected to external terminals 16 and 17 on the surfaces of the leg portions 3 and 3 via wirings 14 and 15 formed inside the intermediate layer 4b, respectively.

  Since the QCM sensor 1 of this embodiment is immersed in the sample solution, when the excitation electrodes 8a and 9a on the front and back surfaces of the crystal piece 7 come into contact with the liquid, the crystal oscillator 5 cannot be oscillated due to a short circuit. . Therefore, an insulating sealing material 18 is filled between the outer peripheral edge of the crystal piece 7 and the inner wall of the storage recess 6 of the package 4 in order to prevent the sample solution from entering the storage recess 6. Sealed.

  In this QCM sensor 1, the surface side of the crystal piece 7 of the crystal unit 5 is a sensing region immersed in the sample solution, and the sensing region includes a sensitive film 10 to which a specific substance to be detected adheres. .

  The QCM sensor 1 having such a configuration is used for, for example, a chemical sensor or a biosensor that detects an organic compound or a biomolecule. Next, a measurement system using the QCM sensor 1 will be described.

  FIG. 2 is a schematic configuration diagram of a measurement system using the QCM sensor 1 of FIG.

  In this measurement system, a specific substance to be detected is injected into a liquid 19 such as a buffer solution by an injection device (not shown) to prepare a sample solution, and the mass of the specific substance in the sample solution is measured. It is.

 The QCM sensor 1 is connected to an external oscillation circuit 20. A sensitive film 10 to which a specific substance adheres is formed on the surface of the excitation electrode 8a of the QCM sensor 1. The QCM sensor 1 is immersed in a liquid 19 such as a buffer solution, and the specific substance to be detected is liquid. 19 is measured. The liquid 19 is maintained at a constant temperature and stirred by a thermostat with a stirring function (not shown).

  First, the oscillation circuit 20 energizes the QCM sensor 1 to oscillate the crystal unit 5, and the frequency counter 21 measures the resonance frequency of the crystal unit 5. Next, a specific substance to be detected is injected into the liquid 19 by an injection device. The liquid 19 into which the specific substance is injected, that is, the specific substance in the sample solution is bonded and attached to the sensitive film 10 of the QCM sensor 1, and the mass of the excitation electrode 8a is increased. As the mass of the excitation electrode 8a increases, the resonance frequency of the crystal unit 5 decreases. By analyzing the decrease amount of the resonance frequency by the computer 22 through the frequency counter 21, the mass of the specific substance in the sample solution is calculated.

  In the measurement using the QCM sensor 1, the waiting time until the oscillation frequency of the crystal unit 5 is stabilized is long, and even when the QCM sensor 1 has the same oscillation frequency, the oscillation frequency is stabilized due to individual differences. Waiting time varies.

  In this embodiment, the waiting time until the start of measurement is shortened and the waiting time variation due to individual differences can be absorbed.

  In other words, in this embodiment, the manufacturer of the QCM sensor 1 uses a transport period until the QCM sensor 1 reaches the user's hand and is used to reduce the waiting time until the measurement is started. Is what you do.

  Specifically, the sensing region including at least the sensitive film 10 of the QCM sensor 1 is shipped while being wetted with a liquid, and the QCM sensor 1 is transported by using a transport period until reaching the user's hand. The sensing area including the sensitive film 10 is made to be sufficiently familiar with the liquid in advance.

  This liquid is preferably a liquid used for preparing a sample solution measured by the QCM sensor 1, but may be another liquid.

  FIG. 3 is a longitudinal side view corresponding to FIG. 1B showing an example of a state holding method of the QCM sensor 1.

  In the state holding of the QCM sensor 1 of this embodiment, the QCM sensor 1 and the liquid 23 in which the QCM sensor 1 is immersed are enclosed as a holding means for holding the sensing area of the QCM sensor 1 wet with the liquid 23. Container 24 is provided.

  That is, the QCM sensor 1 is held in a state immersed in the liquid 23 in the container 24 and shipped in this state.

  The container 24 includes a container body 25 and a lid body 26. The QCM sensor 1 is accommodated in the container body 25, and the liquid 23 is injected and sealed by the lid body 26.

  The liquid 23 is preferably a liquid used for preparing a sample solution used at the time of measurement by the QCM sensor 1, and is preferably a buffer solution such as physiological saline or artificial sweat. The liquid 23 may be pure water.

  The container 24 of this embodiment is made of a resin such as polypropylene, polyethylene, polystyrene, or nylon. Since the sensitive film 10 of the QCM sensor 1 may be composed of a film having an organic functional group, it is preferable that the sensitive film 10 has a light-shielding property so that a decomposition reaction due to light does not occur. For example, a metal such as aluminum is preferably deposited.

  The lid 26 accommodates the QCM sensor 1 in the container body 25 and injects a liquid, and then is sealed by heat welding or the like at the opening edge of the container body 25.

  The container 24 is not limited to resin, but may be metal, not limited to a box shape, and may be a bag shape or other shapes.

  As described above, the QCM sensor 1 is shipped while the sensing region including the sensitive film 10 is immersed in the liquid 23, so that the sensing region becomes sufficiently familiar with the liquid 23 during the transportation period and the like. The user performs measurement using a QCM sensor.

  As described above, since the sensing area of the QCM sensor 1 is immersed in the liquid 23 and becomes fully accustomed before the measurement using the QCM sensor 1 is performed by the user, the QCM sensor 1 is used to detect the specific substance in the sample solution. When measuring the mass or the like, the oscillation frequency of the QCM sensor 1 is stabilized earlier than before, and the waiting time until the measurement of the mass or the like of the specific substance in the sample solution is started can be shortened.

  Even if there are individual differences in the QCM sensor 1, the sensing area of the QCM sensor 1 can be set using the transport period until the QCM sensor 1 is shipped from the manufacturer and reaches the user and used for measurement. Since the liquid can be sufficiently adapted to the liquid, it is possible to absorb variations in waiting time due to individual differences in the QCM sensors 1.

  The reason why the waiting time until the start of measurement by the user can be shortened by shipping the sensing region including the sensitive film 10 of the QCM sensor 1 while being immersed in the liquid 23 is not clear, For example, it can be considered as follows.

  That is, the excitation electrode 8a on which the sensitive film 10 is formed is a laminated film of, for example, chromium (Cr) / gold (Au) as described above, and the upper gold layer is viewed microscopically. For this reason, the liquid 23 penetrates into the underlying chromium layer through the fine porous material and forms a hydrate with chromium, thereby stabilizing the oscillation frequency until the oscillation frequency is stabilized during measurement. It is thought that time can be shortened.

  FIG. 4 is a plan view showing a QCM sensor according to another embodiment of the present invention, and portions corresponding to those in FIG. 1A are denoted by the same reference numerals.

  In the QCM sensor 1a of this embodiment, a mounting groove 27 for mounting an end portion of a container 28, which will be described later, airtightly is provided on the outer peripheral surface of the body portion 2 closer to the leg portion 3 than the crystal resonator 5 is. It is formed over. Other configurations are the same as those of the QCM sensor 1 of FIG.

  FIG. 5 is a longitudinal side view showing a method of maintaining the state of the QCM sensor 1a of FIG. 4, and corresponds to FIG.

  In the embodiment of FIG. 3, the entire QCM sensor 1 is immersed in the liquid 23 and held, whereas in this embodiment, only the portion of the body 2 in which the crystal unit 5 is incorporated is immersed in the liquid 23. It is something to be made.

  That is, in the state holding of the QCM sensor 1a of this embodiment, the quartz crystal resonator 5 is used as a holding means for holding the sensing region of the QCM sensor 1a wet with the liquid 23 rather than the mounting groove 27 of the QCM sensor 1a. A container 28 that encloses the close portion and the liquid 23 is provided. The container 28 is flexible and has an opening 28a on the left side wall in FIG. 5. The liquid 23 is injected from the opening 28a, and the body 2 of the QCM sensor 1a is further removed. The edge of the opening portion 28a of the container 28 is inserted into the mounting groove 27 of the body portion 2 of the QCM sensor 1a due to its elasticity and is brought into close contact therewith.

  Note that the heat shrinkable material may be used so that the opening 28a is contracted by heat and brought into close contact with the mounting groove 27.

  According to this embodiment, since only the portion of the crystal unit 5 of the body 2 of the sensor 1 a is sealed in the container 28, the external terminals 16 and 17 of the leg 3 do not come into contact with the liquid 23. For this reason, even if the liquid 23 is a liquid that corrodes the electrode or the like and the period from the shipment of the QCM sensor 1a to the use by the user is long, the external terminals 16 and 17 of the QCM sensor 1a It will not be corroded by liquid.

  FIG. 6 is a diagram illustrating a state holding method according to another embodiment of the QCM sensor 1 of FIG. 1, and parts corresponding to those in FIG.

  In each of the above embodiments, the sensing region of the QCM sensors 1 and 1a is immersed in a liquid. However, in the shipping form of the QCM sensor 1 of this embodiment, the sensing region including the sensitive film 10 of the QCM sensor 1 is the liquid 23. As a holding means for holding in a wet state, a moisturizing body 29 that absorbs liquid and separates water is provided, and the moisturizing body 29 is placed on the sensing area and in contact with the sensing area. It is to hold.

  As the moisturizing body 29, for example, a highly water-absorbing polymer such as sodium polyacrylate can be used.

  This moisturizing body 29 is preliminarily immersed in the liquid 23 of the above-described embodiment so that the liquid 23 is sufficiently absorbed and placed in close contact with the sensing region of the QCM sensor 1, and a sheet (not shown) is put on and fixed. By holding the moisturizing body 29 in close contact with the sensing area of the QCM sensor 1, the liquid 23 oozes out from the moisturizing body 29 by gravity, and the sensing area can be appropriately wetted.

  The moisturizing body 29 is not limited to sodium polyacrylate, but may be a polyacrylamide, polyoxyethylene, or polyvinyl alcohol polymer, or may be a sponge or other material.

  7A and 7B show a QCM sensor 30 according to another embodiment of the present invention, where FIG. 7A is a plan view and FIG. 7B is a longitudinal side view.

  Whereas the QCM sensor 1, 1 a of the above embodiment is a so-called lead type having the external terminals 16, 17 on the surface of the pair of legs 3, the QCM sensor 30 of this embodiment is a surface mount type. In addition, an IC chip 31 including an oscillation circuit and the like is built in a package 32.

  The package 32 includes a rectangular flat plate-like base material layer 33, first and second upper layers 34 and 35 are formed on the upper surface of the base material layer 33, and a rectangular annular lower layer on the lower surface of the base material layer 33. 36 is formed. The package 32 is formed by firing laminated insulating sheets such as ceramics.

  Circular through holes are formed in the first and second upper layers 34 and 35, respectively, and a storage recess 38 for fitting the crystal resonator 37 is formed. The opening diameter of the second upper layer 35 portion of the storage recess 38 is larger than the opening diameter of the second upper layer 34 portion, and a step portion that supports the peripheral portion of the crystal resonator 37 is formed in the storage recess 38. The

  On the lower surface side of the base material layer 33, a storage recess is formed by the rectangular annular lower layer 36 for storing the IC chip 31 and sealing with the resin 39.

The crystal resonator 37 includes a crystal piece 40 formed in a circular shape, and excitation electrodes 41 a and 42 a are formed in a circular shape at the center of the front and back surfaces of the crystal piece 40.
From each excitation electrode 41a, 42a, extraction electrodes 41b, 42b are formed toward the outer peripheral direction of the crystal piece 40 so as to be opposite to each other. The lead electrode 41b on the front surface side of the crystal piece 40 goes around to the back surface side.

  On the excitation electrode 41a on the surface side of the crystal piece 40, a sensitive film 43 to which a specific substance to be detected adheres by adsorption or the like is formed.

  Connection electrodes 44 and 45 are formed on the upper surface of the stepped portion of the housing recess 38 of the package 32 so as to correspond to the extraction electrodes 41 b and 42 b of the crystal piece 40, and the crystal piece 40 is connected to these connection electrodes 44 and 45. The lead electrodes 41b and 42b are connected via a conductive adhesive 46 such as an epoxy resin.

  The connection electrodes 44 and 45 are connected to electrode pads 47 and 48 on the lower surface of the base material layer 33 by internal wiring (not shown), and the IC chip 31 is connected to the electrode pads 47 and 48 by metal bumps of the IC chip 31. The resin 39 is sealed.

  External terminals 49 for mounting are provided at four locations on the bottom surface of the rectangular annular lower layer 36.

  In the QCM sensor 30 of this embodiment, an insulating sealing is provided between the outer peripheral edge of the crystal piece 40 and the inner wall of the storage recess 38 of the package 32 in order to prevent liquid from entering the storage recess 38. Material 50 is filled and sealed.

  As described above, the QCM sensor 30 has an H-shaped cross section in which the crystal resonator 37 and the IC chip 31 are mounted in the storage recess 38 on the upper surface side and the storage recess on the lower surface side of the base material layer 33 of the package 32, respectively. Therefore, the rigidity can be increased, and the distance between the crystal unit 37 and the oscillation circuit of the IC chip 31 can be shortened, and noise mixing and fluctuations are suppressed as compared with the measurement system of FIG. This can improve the stability of oscillation.

  In particular, the width W1 of the first upper layer 34 constituting the peripheral wall of the storage recess 38 for storing the crystal resonator 37 on the upper surface side of the base material layer 33 of the package 32 is set to the peripheral wall of the storage recess on the lower surface side of the base material layer 33. Is larger than the width W2 of the lower layer 36 that constitutes the lower portion 36, that is, the thickness of the peripheral wall of the housing recess 38 in which the crystal resonator 37 is accommodated is increased. While the stress applied to the child 37 can be reduced, the lower portion of the package 32 can secure a sufficient space for accommodating the IC chip 31.

  FIG. 8 is a cross-sectional view corresponding to FIG. 7B showing a state holding method of the QCM sensor 30 of FIG.

  In the state holding of the QCM sensor 30 of this embodiment, as a holding means for holding the sensing region of the QCM sensor 30 wet with the liquid 23, the upper surface side of the QCM sensor 30 including the sensing region with the liquid 23 put therein And a container 51 for sealing.

  In this embodiment, it is set as the holding | maintenance form shown in FIG. 8 with the following procedures.

  First, in a state where the single container 51 is turned upside down from the state shown in FIG. 8, the liquid 23 is put into the container 51, and the QCM sensor 30 is placed in the container 51 with the crystal resonator 37 on the upper surface side. It is inserted from the side, and is tightly fixed to the outer peripheral edge of the second upper layer 35 of the package 32 by the attaching part 51a at the peripheral part of the container 51, and is turned upside down to the state shown in FIG. Immerse the sensing area. If the sensing area is immersed in the liquid 23, it is not always necessary to turn the container 51 upside down to the state shown in FIG.

  FIG. 9 is a cross-sectional view corresponding to FIG. 7 showing another state holding method of the QCM sensor 30 of FIG.

  In this embodiment, similarly to the embodiment of FIG. 6 described above, a moisture retaining body 29 made of a highly water-absorbing polymer or the like that absorbs liquid and separates water is placed in the sensing region including the sensitive film 43 of the QCM sensor 30. It is a close contact.

  In each of the above embodiments, the QCM sensors 1, 1 a, 30 both form the circular excitation electrodes 8 a, 9 a; 41 a, 42 a on the circular crystal pieces 7, 40 and the circular sensitive films 10, 43. However, the present invention is not limited to a circle, and for example, as shown in FIG. 10 corresponding to FIG. 7, rectangular excitation electrodes 41 a ′ and 42 a ′ are formed on a rectangular crystal piece 37 ′ and a rectangular sensitive film 43 is formed. 'May be formed.

  The QCM sensor 30 ′ of FIG. 10 may be immersed in the liquid or wetted by the moisturizing body 29 as in FIGS. 8 and 9.

(Other embodiments)
If the liquid that immerses or moisturizes the sensing area of the QCM sensor is a liquid that is easily ionized, such as physiological saline, the QCM sensor electrodes, etc., when the period from shipment to use by the user is long However, there is a risk of being corroded by the liquid.

  Therefore, as another embodiment of the present invention, at the time of shipment, for example, the product may be shipped as a refrigerated product of about −10 ° C., transported in a frozen state, and thawed before using the QCM sensor. Thereby, corrosion of the electrodes and the like during the period from shipment of the QCM sensor to its use can be suppressed.

  In this case, in order to familiarize the sensing area of the QCM sensor with the liquid before shipment, a period in which the sensing area is immersed in the liquid or in contact with the moisture retaining body may be secured.

  In addition, depending on the liquid in which the QCM sensor is immersed, the expiration date of use of the QCM sensor may be specified and shipped.

  The material of the QCM sensor package is not limited to ceramic, but may be glass, crystal, silicon, or the like.

  The piezoelectric vibrator is not limited to a flat plate shape, but an inverted mesa structure in which a recess is formed in the central portion of one surface or / and the other surface to increase the thickness around the central portion, or one surface or / and the other surface. A piezoelectric vibrator having a mesa structure or the like in which the thickness of the outer peripheral portion of the surface is thinner than the thickness of the central portion may be used.

  The present invention may be applied to a flow cell type QCM sensor in which a flow path for allowing a sample solution to flow into and out of a sensing region of a crystal resonator is formed.

1,1a, 30,30 ′ QCM sensor 2,32 package 5,37,37 ′ crystal resonator 7,40 crystal piece 8a, 9a; 41a, 42a excitation electrode 10,43 sensitive film 20 oscillation circuit 21 frequency counter 22 computer 23 Liquid 24, 28, 51 Container 31 IC chip

Claims (13)

A method for maintaining a state of a sensor having a sensing region to which a detection target in a sample solution adheres, and a piezoelectric vibrator whose resonance frequency changes due to the attachment of the detection target,
Holding the sensing area wet with liquid;
A method for maintaining the state of a sensor. The piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece,
The sensing region includes a sensitive film formed on the excitation electrode on at least one main surface of the two main surfaces;
Holding the sensing region immersed in the liquid;
The sensor state holding method according to claim 1. The piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece,
The sensing region includes a sensitive film formed on the excitation electrode on at least one main surface of the two main surfaces;
Holding the sensing region in contact with the moisturizer that has absorbed the liquid;
The sensor state holding method according to claim 1. The liquid is a buffer used to prepare the sample solution;
The sensor state holding method according to claim 1. The liquid is physiological saline or artificial sweat;
The sensor state holding method according to any one of claims 1 to 4. The sensor is shipped as a frozen product.
The sensor state holding method according to claim 1. A sensor comprising a piezoelectric vibrator,
The piezoelectric vibrator has a sensing region to which a detection target in a sample solution adheres, and a resonance frequency changes due to the attachment of the detection target,
Holding means for holding the sensing area wet with a liquid;
A sensor characterized by that. The piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece,
The sensing region includes a sensitive film formed on the excitation electrode on at least one main surface of the two main surfaces;
The holding means includes a container that encloses at least the sensing region and the liquid in which the sensing region is immersed.
The sensor according to claim 7. The container has a light shielding property,
The sensor according to claim 8. The piezoelectric vibrator is a crystal vibrator in which excitation electrodes are formed on both main surfaces of the crystal vibrating piece,
The sensing region includes a sensitive film formed on the excitation electrode on at least one main surface of the two main surfaces;
The holding means has a moisturizing body that has absorbed the liquid, and the moisturizing body is in contact with the sensing region.
The sensor according to claim 7. The liquid is a buffer used to prepare the sample solution;
The sensor according to claim 7. The liquid is physiological saline or artificial sweat;
The sensor according to claim 7. The sensor is shipped as a frozen product.
The sensor according to claim 7.

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