JP2003240694A - Multichannel micro mass sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that channels cannot be driven individually due to conductivity between the channels when using a biosensor immersed into an electrolyte solution, in a conventional method in which strip electrodes are wired to orthogonalize the both sides of a substrate to simplify the wiring thereof when a QCM which can detect micro mass is made to be multichanneled. <P>SOLUTION: In the present invention, to electrically separate the channels, the wiring which is not soaked in the solution is arranged for each channel, and the wiring in the solution is commonly arranged. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a system for measuring changes in minute mass. In particular, QCM (Qua) that immobilizes biochemical substances and measures chemical substances such as enzymes, antibodies, proteins, and hormones that specifically adsorb to them.
rtz Crystal Microbalance)
Type biosensor (multi-channel trace mass sensor).

[0002]

2. Description of the Related Art FIG. 2 shows a schematic view of a crystal unit which constitutes a QCM sensor. Basically, electrodes 2a and 2b are formed on both surfaces of a quartz plate 1 which is thinly processed by etching and / or polishing by vapor deposition or the like.
When this crystal oscillator is used as a biosensor, a sensitive film that captures only the analysis target is immobilized on one surface of the electrode.

When an alternating electric field is applied to both electrodes 2a, 2b, vibration of a certain frequency is excited by the inverse piezoelectric effect, but when the analysis target is captured by the sensitive film, the mass increase Δ
As a result, the resonance frequency of the oscillator fluctuates by Δf.

For this bioreaction, various reactions including gas hybridization and liquid reaction such as DNA hybridization reaction, antigen-antibody reaction, protein binding and enzyme reaction can be utilized.

The relationship between the mass addition amount Δm and the vibration frequency change amount Δf is derived from Sauerbrey (G. Sauerbrey, Z. Phy).
s. 155, 1959, 206) can be expressed by the following equation.

[0006]

[Equation 1]

Where f ₀ is the main fundamental frequency of the crystal unit, A is the electrode area, μ _q is the shear elastic coefficient of the crystal, and P _q
Is the density of the crystal. For example, in the case of a crystal oscillator cut out on an AT-cut surface, there is a relationship of the following expression between the thickness t of the crystal plate and the main fundamental frequency.

[0008]

[Equation 2]

Therefore, it can be seen that the higher the main fundamental frequency is, that is, the thinner the crystal plate is, the higher the sensitivity as the mass sensor is.

As an example, in the case of an AT-cut quartz plate having a thickness of 335 μm, the main fundamental frequency is about 5 MHz, the shear elastic modulus μ _q is 2.95 × 10 ¹¹ dyn / cm ² , and the crystal density P _q is 2.65. About 18 ng H from g / cm ³
The sensitivity is z ^-1 cm ^-2 .

In recent years, combinatorial chemistry technology for simultaneously performing many kinds of tests such as DNA chips and protein chips in a short time has been rapidly developed. Further, development of a bio-inspection chip having a composite function, which is called Lab-on-a-Chip or bio-micromachine, has been actively developed. Lab-on-a
Since the Chip type biosensor is compact and inexpensive, it is said to be suitable for, for example, periodically inspecting human health conditions at home or analyzing special gas or odor on the spot. ing. In a biochip used for such a purpose, it is desirable that the sample be operated in a small amount.

The QCM type biosensor described in the present invention is
Lab-on-a that operates with a small amount of sample solution as described above, not only when the QCM sensor unit is immersed in a sample solution or gas that has been conventionally used for inspection.
-The description also includes an application example in which a QCM sensor is incorporated in the inspection portion of a Chip-type biochip and a multi-channel is formed so that multiple types of analysis targets can be detected simultaneously.

[0013]

For the purpose of constructing the above-mentioned multi-channel type QCM biosensor, Japanese Patent Laid-Open No. 8-193854 has been proposed. FIG. 9 shows a schematic diagram in the case of a 3 × 3 multi-array. The invention is
For the purpose of reducing the complexity of wiring when constructing a multi-channel QCM biosensor, at least one strip electrode (51a, 52a, and 53a in FIG. 9) and the other electrode are approximately orthogonal to the strip electrode. Strip-shaped electrodes (51b, 52b, and 53b in FIG. 9) arranged in the same manner
And the intersecting portions (311 to 311 in FIG. 9).
33) is used as an inspection channel, and is driven by a plurality of strip electrodes 51a, 52a, 53a, 51 configured on both sides.
By sequentially switching b, 52b, and 53b by switching circuit elements or the like, the system can sequentially drive each channel.

For example, first, the strip electrodes 51a and 51b.
A voltage is applied to drive the channel 311. Then 5
The channel 312 is driven by blocking the electrolysis to 1a and applying it to 52a. By sequentially repeating such a procedure, it is possible to sequentially measure multiple channels on the piezoelectric substrate 1.

However, when such a multi-channel element is used by immersing it in a sample solution of an electrolyte, the electrodes on the sample solution side are electrically connected between the channels, and it is not possible to individually drive the channels. For example, as in the above example, a voltage is applied to the strip electrodes 51a and 51b, and the channel 3
Even when the driving of No. 11 is tried, when the sample solution is the electrolyte, the entire a-plane side can be regarded as the electrode.

When electrolysis is applied to the strip-shaped electrode 51b on the b-plane side, three locations of channels 311, 312 and 313 are driven. Therefore, the conventional method cannot be used in a method of immersing the entire surface of the multi-channel piezoelectric vibrator in the electrolyte sample solution.

Further, in this method, since there is an inspection channel in the middle of the wiring, a change in the electrical characteristics such as a change in the resistance of the wiring appears due to the reaction of other channels, which affects accurate inspection. It may be given.

Further, in the case of the strip electrode, the difference in the wiring distance between the channels is large, and the change in the electrical characteristics such as the difference in the wiring resistance is likely to appear.

[0019]

DISCLOSURE OF THE INVENTION The present invention is for a multi-channel biosensor in which a plurality of piezoelectric vibrators are arranged in a matrix on a substrate and for which a sensitive film for capturing only a specific analysis target is immobilized. The wiring to the channel side is provided substantially on the entire surface of the substrate, and the opposite surface is an individual wiring for each channel.

The piezoelectric vibrator is characterized in that a reinforcing plate having a shape avoiding the channel portion is adhered and fixed to at least one surface.

The piezoelectric vibrator is characterized in that only a channel portion of at least one surface is thinned.

In a multi-channel biosensor in which a plurality of piezoelectric vibrators are arranged in a matrix on a substrate, wiring to the inspection channel side, on which a sensitive film for capturing only a specific analysis target is immobilized, is at least in every row. Is provided with a common wiring, the opposite surface is provided individually, and the direction of the wiring is substantially the same as the wiring on the surface provided with the sensitive film.

The individually wired electrodes are circular.

The diameters of the individually wired circular electrodes are different on both surfaces of the piezoelectric vibrator.

At least one surface of the individually wired electrodes has a shape in which a circle and a square are combined.

The individual wirings are characterized in that they are connected to the wirings from the end portions of the electrodes having a circular shape or a combination of a circular shape and a square shape.

It is characterized in that the centers of the electrodes shared by at least one column are eccentrically changed in a direction substantially orthogonal to the columns by changing the direction for each channel more than the width of the wiring. A ground layer is provided on the piezoelectric vibrator or between the piezoelectric vibrator and the reinforcing plate.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG.
The outline top view of the first embodiment of the present invention is shown in FIG. In this embodiment, 4 × 4 multi-channels are formed in an array. The wirings 5b are individually provided on the electrode channels 3 (shown by gray circles in the figure) on the side where the sensitive film for capturing a specific molecule is not immobilized (hereinafter referred to as b surface), and The entire surface of the electrode 2a (also serving as the wiring 5a) is arranged on the opposite surface (hereinafter referred to as the "a surface"). The piezoelectric vibrator 1 has an AT
A cut quartz crystal plate is desirable, and as described in the section of the prior art, it is processed so as to have a plate thickness and an electrode area corresponding to the detection sensitivity required for inspection.

Driving of each channel is performed by sequentially switching the electrodes 2b on the b-side. As a result, even when the measurement is performed in a liquid, the measurement can be performed separately without conduction / interference between the channels. Therefore, the provision of the individual electrode 2b on the a-plane side is not established when the sample solution to be inspected is an electric conductor (electrolyte sample solution).

In the arrangement of the present invention, the wiring 5b to the channel 3 on the b-plane can be taken out from both ends of the substrate. This means that even if the length of the wiring 5b on the substrate is at most half the length of one side of the vibrator substrate 1, the wiring length that causes unnecessary noise or the like in the high frequency circuit is determined. It can be made shorter than the case where the strip-shaped electrodes are provided for each of them, which is also advantageous in terms of reduction of wiring resistance.

When the multi-channel QCM type sensor of this embodiment is applied as a biosensor to, for example, an antigen-antibody reaction, the detection channel 3 is provided with a membrane 6 containing an antigen that captures only a specific antibody 7 as a channel electrode. Immobilize on 2a (see FIG. 5). In addition to the antigen-antibody reaction, various biochemical reactions can be applied to this biosensor, but the membrane immobilized on this electrode is a substance that can be adsorbed only to the substance to be analyzed. To use.

When the sample solution 8 contains a substance that can be captured by the membrane 6 immobilized on the channel 3 as described above, the substance is captured on the corresponding channel 3, and as a result, the channel is captured. A change in mass occurs on the electrode 2a, and the trapped amount of the object can be identified through the change in resonance frequency. The oscillation operation at the resonance frequency of each channel 3 may be sequentially oscillated for each channel. In this case, it is not true real-time measurement, but interference between channels can be reduced.

FIG. 6 shows an outline of an example in which the multi-channel QCM biosensor is incorporated into a multifunctional small system such as a Lab-on-a-Chip. In this example, the solution or gas to be analyzed is put into the sensor system through the sample inlet 11, the sample is separated and extracted in the pretreatment element 10, and then introduced into the sensor unit. The pretreatment process may require various other functions such as mixing / reaction, filters, valves, etc.
I will not describe them in detail here.

In addition, a special reagent such as a reaction may be required in the pretreatment step, and a route or inlet for introducing the reagent may be required separately. On the other hand, for moving the sample, a mechanical one using a pump, an electric one using electroosmosis, etc. are widely used.

The sensor section has a QCM sensor arranged for multi-channels, and wiring is provided for each channel (in FIG. 6, wiring on the side not in contact with the sample solution is shown by dotted lines). . The sample solution or gas after the detection is discharged from the discharge port 12.

(Second Embodiment) FIG. 3 (a) is a schematic top view of the second embodiment of the present invention, and FIG. 3 (b) is a sectional view taken along line AA. In this embodiment, 4 × 4 multi-channels are formed in an array. In the first embodiment, the crystal unit substrate 1 has a structure in which only the channel portion 3 is thinned from the b-side, but the reinforcing plate 4 is bonded from at least one side.

The reinforcing plate 4 has an effect of reinforcing the thin piezoelectric vibrator substrate and an effect of vibrationally insulating other channels. Although the plan view of the reinforcing plate 4 is not shown here, it is a flat plate having through holes only in the channel portion 3. The wiring 5b on the b-side may be formed on the reinforcing plate 4 or between the piezoelectric vibrator 1 and the reinforcing plate 4.

The wiring 5b is individually provided on the electrode channel 3 (shown by a black dotted line in the figure) on the side where the sensitive film for capturing a specific molecule is not immobilized (hereinafter referred to as b surface),
The entire surface electrode 5a is arranged on the opposite surface (hereinafter referred to as a surface) of the piezoelectric vibrator substrate 1. The piezoelectric vibrator substrate 1 is preferably an AT-cut crystal vibrator plate,
As mentioned in the section of the prior art, the plate thickness according to the detection sensitivity,
And the electrode area is processed.

Each channel 3 is driven by sequentially switching the individually wired electrodes 2b on the b-side. As a result, there is continuity between channels even when measuring in liquid.
Measurements can be performed separately without interference.
Therefore, the provision of the individual electrode 2b on the a-plane side is not established when the sample solution 8 to be inspected is an electrolyte.

A ground layer may be inserted between the crystal plate 1 and the reinforcing plate 4 as shown in FIG. 4 in order to reduce the influence of noise between the wirings. The ground layer has a pattern formed on the surface b of the crystal unit 1 by vapor deposition or the like so as to avoid the channel portion 3 like the reinforcing plate 4 described above. The hole that avoids the channel portion 3 is a hole that is slightly larger than the hole provided in the reinforcing plate 4, and the wiring 5b on the b-side formed later is formed.
Considering that it does not connect with.

(Third Embodiment) FIG. 7 (a) is a schematic top view of a third embodiment of the present invention, and FIG. 7 (b) is a sectional view taken along line AA. In this embodiment, 4 × 4 multi-channels are formed in an array. The wiring 5b is on the side where the sensitive film for capturing a specific molecule is not immobilized (hereinafter referred to as b
Wirings 5a are individually provided on the electrode channels 3 (denoted by a surface) (indicated by a black dotted line in the figure), and on the opposite surface of the piezoelectric vibrator substrate 1 (hereinafter referred to as a surface) at least in common for each column. It is configured to be.

In this case, the wirings 5a and 5b on both sides are arranged in substantially the same direction. The piezoelectric oscillator substrate 1 is preferably an AT-cut crystal oscillator plate, and is processed to have a plate thickness and an electrode area corresponding to the detection sensitivity, as described in the section of the prior art.

Each channel is driven by the individual wiring 5b on the b-side.
And the application of electrolysis to the common wiring on the a-plane side corresponding thereto are sequentially switched. As a result, even when the measurement is performed in a liquid, the measurement can be performed separately without conduction / interference between the channels. Therefore, the provision of the individual electrode 5b on the a-plane side is not established when the sample solution to be inspected is an electrolyte.

In the arrangement of the present invention, the individual wiring 5b to the channel 3 is taken from both sides which are opposite sides, and is half the length of one side of the vibrator plate 1 at the maximum. Thus, it is possible to reduce the wiring length that causes unnecessary noise and the like, and it is also advantageous in reducing the wiring resistance.

It is desirable that the electrodes 2a and 2b on both sides of the vibrator substrate 1 have different diameters, and that their centers are eccentric to the width of the wiring in the column direction. This makes it easy to take out the individual wiring 5b on the b-side from the end of the electrode 2b to the end of the vibrator substrate 1 linearly and to align the electrodes 2a and 2b on both surfaces of the piezoelectric vibrator substrate 1. . As shown in FIG. 8, the electrodes on both sides of the a and b surfaces may have a shape other than a circular shape, and a combination of a circular shape and a rectangular shape can be used. This also reduces the alignment accuracy when forming the electrodes 2a and 2b on both surfaces, and facilitates the extraction of the wiring to the outside of the substrate.

(Fourth Embodiment) FIG. 10A is a schematic top view of the fourth embodiment of the present invention, and FIG.
A sectional view is shown. In this embodiment, 4 × 4 multi-channels are formed in an array. In the third embodiment, the crystal resonator plate 1 has a structure in which only the channel portion 3 is thinned from the b surface, but the reinforcing plate 4 is bonded from at least one surface.

The reinforcing plate 4 has an effect of reinforcing the thin piezoelectric vibrator substrate and an effect of vibrationally insulating other channels. Although the plan view of the reinforcing plate 4 is not shown here, it is a flat plate having through holes only in the channel portion 3. The wiring 5b on the b-side may be formed on the reinforcing plate 4 or between the piezoelectric vibrator 1 and the reinforcing plate 4.

In the wiring 5b, the electrode channel 3 (shown by a black dotted line in the figure) on the side where the sensitive film for capturing a specific molecule is not immobilized (hereinafter referred to as b surface) is provided individually,
Wirings 5a are commonly provided for each column on the opposite surface (hereinafter referred to as a surface) of the piezoelectric vibrator substrate 1. The piezoelectric vibrator substrate 1 is preferably an AT-cut crystal vibrator plate, and is processed to have a plate thickness and an electrode area corresponding to the detection sensitivity, as described in the section of the prior art.

Each channel is driven by sequentially switching the electrodes 2b on the b-side. As a result, even when the measurement is performed in a liquid, the measurement can be performed separately without conduction / interference between the channels. Therefore, the provision of the individual electrode 2b on the a-plane side is not established when the sample solution to be inspected is an electric conductor (electrolyte sample solution).

A ground layer may be inserted between the crystal plate 1 and the reinforcing plate 4 as shown in FIG. 11 in order to reduce the influence of noise between the wirings. The ground layer has a pattern formed on the surface b of the crystal unit 1 by vapor deposition or the like so as to avoid the channel portion 3 like the reinforcing plate 4 described above. The hole that avoids the channel portion 3 is a hole that is slightly larger than the hole provided in the reinforcing plate 4, and the wiring 5 on the b-side that will be formed later.
It is designed so that it does not connect to b.

[0051]

As described above, according to the present invention, it is possible to provide a multi-channel QCM biosensor which is used by immersing it in a highly accurate electrolyte sample solution without causing interchannel interference.

[Brief description of drawings]

FIG. 1 Multi-channel QCM sensor with full surface electrode

[Fig. 2] Basic configuration of crystal unit

[Fig. 3] Reinforcement plate adhesion type full-surface electrode multi-channel QCM
Sensor

FIG. 4 Reinforcement plate adhesive type multi-channel Q with ground layer
CM sensor

Fig. 5 Outline of chemical reaction on multi-channel biochip

[Fig. 6] Lab- on a multi-channel biochip
Application example to on-a-Chip

FIG. 7: Multi-channel QCM sensor with some common electrodes

[Figure 8] Usable electrode shapes

FIG. 9: Example of strip electrodes arranged orthogonally

FIG. 10: Multi-channel QCM sensor with reinforcing plate adhesive type partial common electrode

FIG. 11 is a multi-channel QCM sensor with a ground plate reinforcing plate adhesive type partially common electrode.

[Explanation of symbols]

1 Crystal oscillator substrate 2a, 2b electrodes 3, 311 to 333 Detection channel 4 Reinforcement plate 5, 5a, 5b wiring 6 capture membrane 7 substances to be analyzed 8 sample solution 9 channels 10 Preprocessing element 11 sample inlet 12 waste exit 13 ground layer

Claims (10)

[Claims] 1. In a multi-channel biosensor in which a plurality of piezoelectric vibrators are arranged in a matrix on a substrate, the wiring to the inspection channel side on which a sensitive film for capturing only a specific analysis target is fixed is generally A multi-channel trace mass sensor characterized in that it has a common electrode on the entire surface, and the opposite surface is individually provided. 2. The multi-channel trace mass sensor according to claim 1, wherein the piezoelectric vibrator has a reinforcing plate adhered and fixed to at least one surface so as to avoid the channel portion. 3. A multi-channel trace mass sensor according to claim 1, wherein the piezoelectric vibrator is thinned only in the channel portion of at least one surface. 4. In a multi-channel biosensor in which a plurality of piezoelectric vibrators are arranged in a matrix on a substrate, at least the wiring to the inspection channel side, on which a sensitive film for capturing only a specific analysis target is fixed, is provided. A multi-channel trace mass sensor characterized in that common wiring is provided for each row, the opposite surface is provided individually, and the direction of the wiring is almost the same as the wiring on the surface provided with the sensitive film. . 5. The multi-channel trace mass sensor according to claim 1, wherein the individually wired electrodes are circular. 6. The multi-channel trace mass sensor according to claim 4, wherein the diameters of the individually wired circular electrodes are different on both surfaces of the piezoelectric vibrator. 7. The multi-channel mass sensor according to claim 4, wherein at least one surface of the individually wired electrodes has a shape in which a circle and a square are combined. 8. The multi-channel trace mass sensor according to claim 4, wherein the individual wiring is connected to the wiring from an end portion of the electrode having the circular shape or a combination of a circular shape and a rectangular shape. 9. The center of the electrode shared by at least one column is decentered by changing the direction of each channel by a width of the wiring or more in a direction substantially orthogonal to the column. Multi-channel trace mass sensor. 10. The multi-channel trace mass sensor according to claim 1, wherein a ground layer is provided on the piezoelectric vibrator or between the piezoelectric vibrator and a reinforcing plate.