JP2010085114A - Support apparatus for analysis of biopolymer - Google Patents

Abstract

An object of the present invention is to make it possible to easily identify the sequence of sample DNA.
A biopolymer analysis support apparatus 80 includes a solid-state imaging device 10, a plurality of types of spots 60 made of a known biopolymer, scattered on a light receiving surface of the solid-state imaging device 10, and the solid-state imaging device 10. Of the driving circuit 70 that outputs a signal corresponding to the amount of light received by the pixels of the solid-state imaging device 10, a subtractor 87 that subtracts the output of the driving circuit 70, and outputs the difference. A variable gain amplifier 88 that amplifies the output and an A / D converter 89 that quantizes the output of the variable gain amplifier 88 are provided. A subtractor 87 aligns the minimum value of the output range of the drive circuit 70 with the lower limit value of the input dynamic range of the variable gain amplifier 88. The variable gain amplifier 88 adjusts the output range of the subtractor 87 to be within the input dynamic range of the A / D converter 89.
[Selection] Figure 7

Description

  The present invention relates to a biopolymer analysis support apparatus using a solid-state imaging device.

  In recent years, we have been analyzing gene expression of various species. Gene expression analysis is to identify a gene expressed in a cell, and specifically, to identify mRNA transcribed from DNA encoding the gene.

  A DNA microarray and its reader have been developed for gene expression analysis. A DNA microarray is obtained by aligning and fixing cDNA having a known base sequence serving as a probe in a matrix on a solid support such as a slide glass (see, for example, Patent Document 1). Here, as a cDNA having a known base sequence, a cDNA having the same base sequence as that of a known mRNA in a specimen or a part thereof is used. Gene expression analysis using a DNA microarray and its reader is performed as follows.

  First, a DNA microarray is prepared in which a plurality of types of cDNAs with known sequences (hereinafter referred to as probe DNA) are aligned and fixed on a solid support such as a slide glass. Next, mRNA is extracted from the specimen, and cDNA labeled with a fluorescent substance (hereinafter referred to as sample DNA) is synthesized using reverse transcriptase. Next, when the sample DNA is labeled with a fluorescent substance and then added to the DNA microarray, the sample DNA is immobilized on the DNA microarray by hybridizing with the complementary probe DNA. When excited, the fluorescent substance that labels the sample DNA emits fluorescence from the position of the probe DNA to which the sample DNA is bound.

Next, the DNA microarray is set in a reader and analyzed by the reader. The reader moves the irradiation point of excitation light two-dimensionally with respect to the DNA microarray, and simultaneously scans the DNA microarray two-dimensionally with a condenser lens and a photomultiplier. The fluorescence emitted from the fluorescent material excited by the excitation light is collected by a condensing lens, and the fluorescence intensity is measured with a photomultiplier to measure the fluorescence intensity distribution in the surface of the DNA microarray. The fluorescence intensity distribution on the microarray is output as a two-dimensional image. In the output image, the portion having high fluorescence intensity indicates that sample DNA having a base sequence complementary to the base sequence of the probe DNA is included. Therefore, it is possible to identify which mRNA of the known sequence is expressed in the specimen depending on which part of the two-dimensional image has high fluorescence intensity.
JP 2000-1312237 A

  Incidentally, the inventors have developed a biopolymer analysis chip in which probe DNA is spotted on the light receiving surface of a solid-state imaging device. In such a biopolymer analysis chip, a bright part of an image acquired by a solid-state imaging device corresponds to a spot to which sample DNA is attached. Therefore, by specifying the bright part, the spot to which the sample DNA is attached can be specified, and the sequence of the sample DNA can be specified. In such a biopolymer analysis chip, since the spots are scattered on the light receiving surface of the solid-state imaging device, there is an advantage that a lens or the like is not required and the apparatus is downsized.

However, since the light emitted from the spot is weak, it is difficult to distinguish between a bright part and a dark part in the image acquired by the solid-state imaging device, and it is difficult to specify the sequence of the sample DNA.
Therefore, the present invention has been made to solve such problems, and is to make it possible to easily specify the sequence of sample DNA.

In order to solve the above problems, according to the present invention,
A solid-state imaging device;
A plurality of types of spots made of known biopolymers and scattered on the light receiving surface of the solid-state imaging device,
A drive circuit that drives the solid-state imaging device and outputs a signal corresponding to the amount of light received by the pixels of the solid-state imaging device;
A subtractor that subtracts the output of the drive circuit and outputs the difference;
An amplifier for amplifying the output of the subtractor;
An A / D converter that quantizes the output of the amplifier,
The subtractor aligns the minimum value of the output range of the drive circuit with the lower limit value of the input dynamic range of the amplifier,
A biopolymer analysis support device is provided in which the amplifier adjusts the output range of the subtractor to fall within the input dynamic range of the A / D converter.

Preferably, the amplifier adjusts the output range of the subtractor to be equal to the input dynamic range of the A / D converter.
Preferably, the amplifier is a variable gain amplifier,
The amplifier has a reference upper limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel in a state where light of maximum intensity is incident on the pixel of the solid-state imaging device, and light is incident on the pixel of the solid-state imaging device In a state in which the output is not performed, the output of the subtracter is amplified with a gain corresponding to the difference from the reference lower limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel.
Preferably, the biopolymer analysis support device is
A storage device storing the reference upper limit voltage and the reference lower limit voltage;
A controller that reads the reference upper limit voltage and the reference lower limit voltage from the storage device and sets a gain of the amplifier based on a difference therebetween.
Preferably, the subtracter subtracts a reference lower limit voltage representing an output of the drive circuit by photoelectric conversion of the pixel of the pixel of the solid-state imaging device from an output of the drive circuit in a state where light is not incident on the pixel.
Preferably, the biopolymer analysis support device is
A storage device storing the reference lower limit voltage;
A controller that reads the reference lower limit voltage from the storage device and outputs the reference lower limit voltage to an inverting input terminal of the subtractor,
The output of the drive circuit is input to the non-inverting input terminal of the subtracter.
Preferably, the subtracter subtracts a reference lower limit voltage representing an output of the driving circuit by photoelectric conversion of the pixel in a state where light is not incident on the pixel of the solid-state imaging device from the output of the driving circuit,
The amplifier is a variable gain amplifier;
The amplifier has a gain corresponding to the difference between the reference upper limit voltage and the reference lower limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel in a state where light of maximum intensity is incident on the pixel of the solid-state imaging device To amplify the output of the subtractor.
Preferably, the biopolymer analysis support device is
A storage device storing the reference upper limit voltage and the reference lower limit voltage;
The reference upper limit voltage and the reference lower limit voltage are read from the storage device, the read reference lower limit voltage is output to the inverting input terminal of the subtractor, and based on the difference between the read reference upper limit voltage and the reference lower limit voltage. A controller for setting the gain of the amplifier,
The output of the drive circuit is input to the non-inverting input terminal of the subtracter.
Preferably, the storage device is mounted on the solid-state imaging device.

  According to the present invention, the resolution of the output of the A / D converter can be utilized to the maximum extent. Therefore, the difference in brightness between the fluorescent portion and the non-fluorescent portion of the image output from the A / D converter increases. In this case, it is easy to specify a fluorescent part from the output image. That is, it is easy to specify the spot of the probe DNA complementary to the fluorescently labeled DNA.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

[1] Overall Configuration of Biopolymer Analysis Chip FIG. 1 is a schematic perspective view showing the biopolymer analysis chip 1 and the excitation light irradiation device 81 used in the biopolymer analysis device according to the embodiment of the present invention.
As shown in FIG. 1, the biopolymer analysis chip 1 includes a solid-state imaging device 10, spots 60, 60..., A drive circuit 70, and a storage device 82.

The solid-state imaging device 10 is attached below the excitation light irradiation device 81. Further, the solid-state imaging device 10 can be removed from a position below the excitation light irradiation device 81.
The spots 60, 60... Are spotted on the light receiving surface of the effective pixel region 11 of the solid-state imaging device 10.
The drive circuit 70 and the storage device 82 are mounted in the area 12 around the effective pixel area 11. A flexible wiring sheet 83 is connected to the drive circuit 70 and the storage device 82.

[2] Solid-State Imaging Device The solid-state imaging device 10 will be described with reference to FIGS. FIG. 2 is an enlarged plan view of one spot 60 in FIG. FIG. 3 is a plan view showing one double gate transistor 20. 4 is a cross-sectional view taken along the line IV-IV shown in FIG.

  As shown in FIG. 2, the solid-state imaging device 10 has a plurality of double gate transistors 20, 20,. The solid-state imaging device 10 is provided with a plurality of bottom gate lines 41, source lines 42, drain lines 43, and top gate lines 44.

  As shown in FIG. 4, the solid-state imaging device 10 includes a transparent substrate 13, a bottom gate insulating film 22, a top gate insulating film 29, a protective insulating film 32, an excitation light shielding film 33, and a spot fixing layer 34. Are laminated.

  The transparent substrate 13 has a property of transmitting light (hereinafter referred to as “light transmissive”) and an insulating property, and is a glass substrate (for example, a quartz glass substrate), a plastic substrate (for example, made of polycarbonate or PMMA). Substrate) Other insulating transparent substrate.

The bottom gate insulating film 22, the top gate insulating film 29, and the protective insulating film 32 have insulating properties and light transmissive properties. The bottom gate insulating film 22, the top gate insulating film 29, and the protective insulating film 32 have insulating properties and light transmissive properties, and are, for example, a silicon nitride film or a silicon oxide film.
The excitation light shielding film 33 has a property of shielding excitation light (for example, light in the ultraviolet wavelength region) emitted from the excitation light irradiation device 81 and transmitting fluorescence (for example, light in the visible light wavelength region).
The spot fixing layer 34 fixes the spot 60 by covalently bonding the probe to be the spot 60 with a silane coupling agent or the like.

  In the solid-state imaging device 10, the double gate transistor 20 is used as a photoelectric conversion element, and the double gate transistor 20 is a pixel. A plurality of double gate transistors 20, 20,... Are arranged on the transparent substrate 13 in a two-dimensional array, particularly in a matrix. These double gate transistors 20, 20,... Are collectively covered with a protective insulating film 32. 3 shows 100 double gate transistors 20, 20,... Of 10 rows × 10 columns.

  4 and 5, the double gate transistor 20 includes a bottom gate electrode 21, a semiconductor film 23, a channel protective film 24, an impurity semiconductor film 25, an impurity semiconductor film 26, a source electrode 27, a drain electrode 28, and a top gate. An electrode 31 is provided.

  The bottom gate electrode 21 is formed between the transparent substrate 13 and the bottom gate insulating film 22. The semiconductor film 23, the channel protective film 24, the impurity semiconductor film 25, the impurity semiconductor film 26, the source electrode 27 and the drain electrode 28 are formed between the bottom gate insulating film 22 and the top gate insulating film 29. The top gate electrode 31 is formed between the top gate insulating film 29 and the protective insulating film 32.

  The bottom gate electrode 21 is formed on the transparent substrate 13 for each double gate transistor 20. Further, a plurality of bottom gate lines 41, 41,... Are formed between the transparent substrate 13 and the bottom gate insulating film 22, and these bottom gate lines 41, 41,. It is extended. The bottom gate electrodes 21 of the double gate transistors 20, 20,... In the same row arranged in the horizontal direction are formed integrally with a common bottom gate line 41. The bottom gate electrode 21 and the bottom gate line 41 have conductivity and light shielding properties, and are made of, for example, chromium, a chromium alloy, aluminum, an aluminum alloy, or an alloy thereof.

  The semiconductor film 23 is opposed to the bottom gate electrode 21 with the bottom gate insulating film 22 interposed between the semiconductor film 23 and the bottom gate electrode 21. The semiconductor film 23 is formed independently for each double gate transistor 20. The semiconductor film 23 is a light receiving part, and an amount of electron-hole pairs corresponding to the amount of light incident on the semiconductor film 23 is formed in the semiconductor film 23. The semiconductor film 23 is made of amorphous silicon.

  The channel protective film 24 is formed on the central portion of the semiconductor film 23. The channel protective film 24 is independently patterned for each double gate transistor 20. The channel protective film 24 has insulating properties and light transmissive properties, and is made of, for example, silicon nitride or silicon oxide. The channel protective film 24 protects the semiconductor film 23 from an etchant used for patterning. When light enters the semiconductor film 23, an amount of electron-hole pairs according to the amount of incident light is generated around the interface between the channel protective film 24 and the semiconductor film 23.

The impurity semiconductor film 25 is formed so as to overlap a part of the semiconductor film 23. Part of the impurity semiconductor film 25 overlaps the channel protective film 24. The impurity semiconductor film 26 is formed so as to overlap another part of the semiconductor film 23. Part of the impurity semiconductor film 26 overlaps with the channel protective film 24. The impurity semiconductor films 25 and 26 are patterned independently for each double gate transistor 20. The impurity semiconductor films 25 and 26 are made of amorphous silicon (n ⁺ silicon) containing n-type impurities (for example, phosphine).

  The source electrode 27 overlaps the impurity semiconductor film 25. The drain electrode 28 overlaps the impurity semiconductor film 26. The source electrode 27 and the drain electrode 28 are formed for each double gate transistor 20. A plurality of source lines 42, 42,... And drain lines 43, 43,... Are formed between the bottom gate insulating film 22 and the top gate insulating film 29. The source lines 42, 42,. 43, 43,... Extend in the vertical direction. The source electrodes 27 of the double gate transistors 20, 20,... In the same column arranged in the vertical direction are formed integrally with the common source line 42, and the double gates in the same column arranged in the vertical direction. The drain electrodes 28 of the transistors 20, 20,... Are integrally formed with a common drain line 43. The source electrode 27, the drain electrode 28, the source line 42, and the drain line 43 have conductivity and light shielding properties, and are made of, for example, chromium, a chromium alloy, aluminum, an aluminum alloy, or an alloy thereof.

  The top gate electrode 31 is opposed to the semiconductor film 23 with the channel protective film 24 and the top gate insulating film 29 sandwiched between the top gate electrode 31 and the semiconductor film 23. The top gate electrode 31 is formed on the top gate insulating film 29 for each double gate transistor 20. Further, a plurality of top gate lines 44, 44,... Are formed between the top gate insulating film 29 and the protective insulating film 32, and these top gate lines 44, 44,. It extends to. The top gate electrodes 31 of the double gate transistors 20, 20,... In the same row arranged in the horizontal direction are formed integrally with a common top gate line 44. The top gate electrode 31 and the top gate line 44 are conductive and light transmissive, for example, indium oxide, zinc oxide, tin oxide, or a mixture containing at least one of them (for example, tin-doped indium oxide ( ITO) and zinc-doped indium oxide).

  The solid-state imaging device 10 configured as described above uses the surface of the spot fixing layer 34 as a light-receiving surface, and the amount of light received by the semiconductor film 23 of the double-gate transistor 20 when the solid-state imaging device 10 is driven becomes an electrical signal. Converted.

[3] Spots As shown in FIGS. 1 and 2, a plurality of spots 60 are formed on the light receiving surface of the solid-state imaging device 10 (the surface of the spot fixing layer 34). Each spot 60 is formed by dropping a solution of cDNA (probe DNA) having a known base sequence serving as a probe or an antibody onto the light receiving surface of the solid-state imaging device 10 and drying it. Hereinafter, a case where cDNA having a known base sequence is used as a probe will be described.

In one spot 60, a crowd of many single-stranded probe DNAs having the same base sequence is immobilized, and the base sequences of the probe DNAs are different for each spot 60. As the probe DNA, a known mRNA base sequence is used, or a DNA having the same or complementary base sequence as a part thereof is used. Specifically, for example, a cDNA library prepared from the same cell specimen as that used for fluorescently labeled DNA can be used.
As shown in FIG. 2, one spot 60 is formed so as to overlap a plurality of double gate transistors 20.

[4] Driving Circuit FIG. 5 is a circuit diagram showing the solid-state imaging device 10 and its peripheral circuits.
The drive circuit 70 shown in FIG. 1 includes a top gate driver 71, a bottom gate driver 72, and a drain driver 73 as shown in FIG.

  Are connected to the terminals of the top gate driver 71, the bottom gate lines 41, 41,... Are connected to the terminals of the bottom gate driver 72, and the drain lines 43, 43,. Is connected to the terminal of the drain driver 73. Further, the source lines 42, 42,... Of the solid-state imaging device 10 are connected to a constant voltage source, and in this example, the source lines 42, 42,. The top gate driver 71, the bottom gate driver 72, and the drain driver 73 cooperate to drive the solid-state imaging device 10.

FIG. 6 is a timing chart showing transition of signals for driving the solid-state imaging device 10.
As shown in FIG. 6, the top gate driver 71 sequentially outputs reset pulses to the top gate lines 44, 44,. The level of the reset pulse is a high level of +5 [V]. On the other hand, the top gate driver 71 applies a low level potential of −20 [V] to each top gate line 44 when no reset pulse is output. As the top gate driver 71, a shift register can be used.

  The bottom gate driver 72 sequentially outputs read pulses to the bottom gate lines 41, 41,. The level of the read pulse is +10 [V] on level (high level), and the level when the read pulse is not output is ± 0 [V] off level (low level). As the bottom gate driver 72, a shift register can be used.

  The top gate driver 71 outputs a read pulse to the bottom gate line 41 of the same row after the carrier accumulation period after the top gate driver 71 outputs the reset pulse to the top gate line 44 of any row. 71 and bottom gate driver 72 shift the output signal. That is, in each row, the timing at which the read pulse is output is delayed from the timing at which the reset pulse is output. The period from the start of reset pulse input to the top gate line 44 of any row to the end of read pulse input to the bottom gate line 41 of the same row is the selection period of that row. is there. The level of the reset pulse is a high level of +5 [V], and the level when the reset pulse is not output is a low level of −20 [V].

  The drain driver 73 outputs a precharge pulse to all the drain lines 43, 43,... Between the reset pulse output and the read pulse output in the selection period of each row. ing. The level of the precharge pulse is a high level of +5 [V], and the level when the precharge pulse is not output is a low level of ± 0 [V]. The drain driver 73 outputs the voltages of the drain lines 43, 43,... In a column sequence after outputting the precharge pulse.

An imaging operation of the solid-state imaging device 10 by the drive circuit 70 will be described.
The top gate driver 71 sequentially outputs reset pulses from the top gate line 44 of the first row to the top gate line 44 of the last row, and the bottom gate driver 72 sequentially reads read pulses to the bottom gate lines 41, 41, 41,. Is output. At that time, the drain driver 73 outputs a precharge pulse to all the drain lines 43, 43,... Between the reset period in which the reset pulse is output in each row and the period in which the read pulse is output in each row. .

  The operation of each double gate transistor 20 in the i-th row will be described in detail. When the top gate driver 71 outputs a reset pulse to the i-th top gate line 44, the i-th top gate line 44 goes to a high level. While the i-th top gate line 44 is at a high level (this period is referred to as a reset period), in each double-gate transistor 20 in the i-th row, the semiconductor film 23 and the channel protective film 24 are included in the semiconductor film 23. The carriers (here, holes) accumulated near the interface with the repulsion are discharged by being repelled by the voltage of the top gate electrode 31.

  Next, the top gate driver 71 finishes outputting the reset pulse to the i-th top gate line 44, and the electron-hole generated in the semiconductor film 23 by the fluorescence incident on the semiconductor film 23. A negative potential (−20 [V]) is output to the top gate line 44 in order to electrically capture holes in the pair. That is, after the reset pulse of the top gate line 44 in the i-th row ends, the read pulse is output to the bottom gate line 41 in the i-th row (this period is referred to as a carrier accumulation period). A corresponding amount of electron-hole pairs is generated in the semiconductor film 23, and the holes are generated in the semiconductor film 23 or in the vicinity of the interface between the semiconductor film 23 and the channel protective film 24 by the electric field of the top gate electrode 31. Accumulated.

  Next, during the carrier accumulation period, the drain driver 73 outputs a precharge pulse to all the drain lines 43, 43,. While the precharge pulse is output (referred to as a precharge period), in each double gate transistor 20 in the i-th row, the potential applied to the top gate electrode 31 is −20 [V]. Then, the electric field due to the holes accumulated in the semiconductor film 23 or in the vicinity of the interface between the semiconductor film 23 and the channel protective film 24 due to the negative electric field inevitably cancels the negative electric field completely, so that the channel region of the semiconductor film 23 is obtained. Therefore, it cannot be a positive electric field that can form an n-channel. Then, since the potential applied to the bottom gate electrode 21 is ± 0 [V], a channel is formed in the semiconductor film 23 even if a potential difference of the precharge pulse occurs between the drain electrode 28 and the source electrode 27. In other words, no current flows between the drain electrode 28 and the source electrode 27. Since no current flows between the drain electrode 28 and the source electrode 27 during the precharge period, the drain electrode 28 of each double gate transistor 20 in the i-th row is output by the precharge pulse output to the drain lines 43, 43,. Is charged.

  Next, the drain driver 73 finishes outputting the precharge pulse, and the bottom gate driver 72 outputs a read pulse to the i-th bottom gate line 41. While the bottom gate driver 72 outputs a read pulse to the i-th bottom gate line 41 (this period is referred to as a read period), +10 is applied to the bottom gate electrode 21 of each i-th double gate transistor 20. Since the potential of [V] is applied, each double gate transistor 20 in the i-th row is turned on.

  In the lead period, since the carriers accumulated in the carrier accumulation period work so as to alleviate the negative electric field of the top gate electrode 31, if the amount of incident light is sufficient and the amount of carriers is sufficient, the bottom gate electrode An n channel is formed in the semiconductor film 23 together with the positive electric field 21, and a current flows from the drain electrode 28 to the source electrode 27. Therefore, in the read period, the voltages of the drain lines 43, 43,... Tend to gradually decrease with time due to the drain-source current.

  As the amount of light incident on the semiconductor film 23 in the carrier accumulation period increases, the number of accumulated carriers also increases. As the number of accumulated carriers increases, the level of current flowing from the drain electrode 28 to the source electrode 27 in the read period also increases. Become. Therefore, the decreasing tendency of the voltage of the drain lines 43, 43,... During the lead period is deeply related to the amount of light incident on the semiconductor film 23 during the carrier accumulation period.

  .. Between the i-th read period and the next (i + 1) -th precharge period, the voltage of the drain lines 43, 43,. 73. The voltage indicates the amount of light. The drain driver 73 outputs the voltages of the drain lines 43, 43,... In column order (Vout).

  A series of image reading operations described above is set as one cycle, and the same processing procedure is repeated for all the double gate transistors 20 in all rows, thereby obtaining a light amount distribution on the light receiving surface of the solid-state imaging device 10.

[5] Storage Device The storage device 82 shown in FIG. 1 is a hard disk drive or a semiconductor storage device.
The storage device 82 stores a reference upper limit voltage Vmax and a reference lower limit voltage Vmin.

  The reference lower limit voltage Vmin is an output voltage of the drive circuit 70 by photoelectric conversion of the double gate transistor 20 in a state where light is not incident on the double gate transistor 20 of the solid-state imaging device 10. The reference lower limit voltage Vmin is obtained by a preliminary test. Specifically, the solid-state imaging device 10 is driven by the drive circuit 70 without irradiating the solid-state imaging device 10 with light, and the output voltage of the double gate transistor 20 output from the drain driver 73 at that time is measured. The measured voltage is the reference lower limit voltage Vmin.

  The reference upper limit voltage Vmax is an output voltage of the drive circuit 70 by photoelectric conversion of the double gate transistor 20 in a state where light of maximum intensity is incident on the double gate transistor 20 of the solid-state imaging device 10. The reference upper limit voltage Vmax is obtained by a preliminary test. Specifically, cDNA complementary to the probe DNA of any of the spots 60 is prepared, the cDNA is labeled with a phosphor, the fluorescently labeled cDNA is applied to the spot 60, and the probe DNA of the spot 60 is coated. And the fluorescently labeled cDNA are hybridized. When the spot 60 is irradiated with excitation light after hybridization, fluorescence is emitted from the spot 60 by the phosphor. Since the cDNA complementary to the probe DNA of the spot 60 was prepared, the cDNA was bound to almost 100% of the probe DNA, and the intensity of fluorescence emitted from the spot 60 was maximized. In this state, the solid-state imaging device 10 is driven by the drive circuit 70, and the output voltage of the double-gate transistor 20 (below the spot 60 emitting the maximum intensity fluorescence) output from the drain driver 73 at that time is measured. The measured voltage is the reference upper limit voltage Vmax.

[6] Biopolymer Analysis Device Since the biopolymer analysis chip 1 is used by setting the biopolymer analysis chip 1 in the biopolymer analysis support device 80, the biopolymer analysis support device 80 will be described with reference to FIG. To do. FIG. 7 is a block diagram showing the configuration of the biopolymer analysis support device 80.

  In addition to the biopolymer analysis chip 1, the biopolymer analysis support device 80 includes an excitation light irradiation device 81, a controller 84, an output device 85, a memory 86, a subtractor 87, a variable gain amplifier 88, and an A / D converter 89. Prepare.

  The storage device 82, the top gate driver 71, the bottom gate driver 72, and the drain driver 73 are connected to the controller 84 by the flexible wiring sheet 83 shown in FIG. The output terminal of the drain driver 73 is connected to the non-inverting input terminal of the subtractor 87 by the flexible wiring sheet 83.

The controller 84 has a function of turning on / off the excitation light irradiation device 81.
The controller 84 has a function of reading the reference upper limit voltage Vmax and the reference lower limit voltage Vmin stored in the storage device 82.
The controller 84 has a function of outputting the read reference lower limit voltage Vmin to the inverting input terminal of the subtractor 87.
The controller 84 has a function of setting the gain of the variable gain amplifier 88 based on the difference between the read reference upper limit voltage Vmax and the reference lower limit voltage Vmin.
Further, the controller 84 outputs a control signal to the top gate driver 71, the bottom gate driver 72 and the drain driver 73, thereby driving the solid-state imaging device 10 to the top gate driver 71, the bottom gate driver 72 and the drain driver 73. Has the function to perform.

  The subtractor 87 adjusts the output level of the drain driver 73 so that the minimum value of the output range of the drain driver 73 is equal to the lower limit value of the input dynamic range of the variable gain amplifier 88. Specifically, the subtractor 87 subtracts the reference lower limit voltage Vmin from the output of the drain driver 73 and outputs the difference result. As a result, the lower limit value of the output of the subtractor 87 becomes equal to the lower limit value of the input dynamic range of the variable gain amplifier 88.

The variable gain amplifier 88 adjusts (compresses / decompresses) the output range of the subtractor 87 and puts the output range in the input dynamic range of the A / D converter 89. Specifically, the variable gain amplifier 88 amplifies the output of the subtractor 87 according to the gain (amplification degree) set by the controller 84. Here, if the input dynamic range of the A / D converter 89 is Vrange (unit: voltage), the gain G of the variable gain amplifier 88 is set as follows.
G ≦ Vrange / (Vmax−Vmin)
As a result, the output range of the variable gain amplifier 88 falls within the input dynamic range of the A / D converter 89. In particular, if G = Vrange / (Vmax−Vmin), the maximum value of the output range of the variable gain amplifier 88 becomes equal to the upper limit value of the input dynamic range of the A / D converter 89, and the output of the variable gain amplifier 88. The minimum value of the range becomes equal to the lower limit value of the input dynamic range of the A / D converter 89. Therefore, the output resolution of the A / D converter 89 can be utilized to the maximum extent.

  The A / D converter 89 quantizes the output of the variable gain amplifier 88 and outputs the result.

  The controller 84 has a function of recording the output of the A / D converter 89 in the memory 86. Thereby, the light quantity distribution along the light receiving surface of the solid-state imaging device 10 is recorded in the memory 86 as two-dimensional image data.

  The controller 84 has a function of causing the output device 85 to output an image according to the image data recorded in the memory 86. As a result, the output device 85 outputs an image. The output device 85 is, for example, a plotter, a printer, or a display.

[7] Analysis Procedure A method for analyzing a sample using the biopolymer analysis support apparatus 80 will be described, and a method for using and operating the biopolymer analysis support apparatus 80 will be described.

[7-1] Preparation of fluorescently labeled DNA DNA can be used as a sample to be analyzed. As a sample DNA, mRNA obtained by extracting mRNA expressed in an arbitrary cell specimen and performing RT-PCR reaction using reverse transcriptase can be used. The cDNA is labeled with a fluorophore. As the phosphor, for example, Cy2 (absorption wavelength 491 nm, fluorescence wavelength 509 nm), Cy3 (absorption wavelength 553 nm, fluorescence wavelength 569 nm), Cy5 (absorption wavelength 645 nm, fluorescence wavelength 664 nm) manufactured by GE Healthcare Bioscience Co., Ltd. are used. be able to.

  In order to label cDNA with a phosphor, for example, an RT-PCR reaction may be performed using an oligo dT primer labeled with a phosphor or a labeled dNTP mix. Hereinafter, this labeled cDNA is referred to as fluorescently labeled DNA.

[7-2] Hybridization First, an operator applies a solution containing fluorescence-labeled DNA (hereinafter, fluorescence-labeled DNA) to the light-receiving surface of the solid-state imaging device 10. The fluorescently labeled DNA solution may be dropped on each of the spots 60, 60,.

  At this time, the fluorescently labeled DNA solution is heated so that the DNA becomes a single strand. Further, the light receiving surface of the solid-state imaging device 10 is also heated so that the DNA of the spot 60 becomes a single strand.

  Next, the solid-state imaging device 10 is cooled. Then, of the fluorescently labeled DNA in the fluorescently labeled DNA solution, the fluorescently labeled DNA complementary to the probe DNA of the spot 60 hybridizes with the probe DNA. On the other hand, fluorescently labeled DNA that is not complementary to the probe DNA does not bind to the spot 60, or even if it binds to the spot 60.

  Thereafter, the fluorescence-labeled DNA solution is washed away from the light-receiving surface of the solid-state imaging device 10 with a washing buffer solution, and the non-hybridized fluorescent-labeled DNA is removed from the light-receiving surface of the solid-state imaging device 10.

[7-3] Detection of Sample After performing the above processing, the biopolymer analysis chip 1 is set in the biopolymer analysis support device 80. As a result, the top gate driver 71, the bottom gate driver 72, the drain driver 73, and the storage device 82 are connected to the controller 84, and the drain driver 73 is connected to the subtractor 87. Thereafter, the controller 84 is activated.

When the controller 84 is activated, the reference upper limit voltage Vmax and the reference lower limit voltage Vmin stored in the storage device 82 are read by the controller 84.
The controller 84 outputs the reference lower limit voltage Vmin to the inverting input terminal of the subtractor 87. As a result, the minimum value of the output range of the subtractor 87 is aligned with the lower limit value of the input dynamic range of the variable gain amplifier 88.
The controller 84 sets the gain of the variable gain amplifier 88 to the gain G based on the difference between the reference upper limit voltage Vmax and the reference lower limit voltage Vmin. As a result, the output range of the variable gain amplifier 88 falls within the input dynamic range of the A / D converter 89, and more specifically, the output range of the variable gain amplifier 88 becomes the input dynamic range of the A / D converter 89. Will be equal.

  Subsequently, the controller 84 turns on the excitation light irradiation device 81. The spots 60, 60,... Are irradiated by the excitation light irradiation device 81. Then, fluorescence is emitted from the spot 60 where the fluorescently labeled DNA is bound to the probe DNA. On the other hand, no fluorescence is emitted from the spot 60 where the fluorescently labeled DNA is bound to the probe DNA.

  Then, the controller 84 outputs a control signal to the top gate driver 71, the bottom gate driver 72, and the drain driver 73 with the excitation light irradiation device 81 turned on. Then, as described above, the solid-state imaging device 10 is driven by the top gate driver 71, the bottom gate driver 72, and the drain driver 73, and photoelectric conversion occurs in the double gate transistors 20, 20,. And the voltage (voltage of the drain electrode 28) according to the light quantity in the double gate transistors 20, 20,.

  The difference between the output of the drain driver 73 and the reference lower limit voltage Vmin is taken by the subtractor 87, and the difference is outputted from the subtractor 87. The output of the subtractor 87 is amplified by the gain G by the variable gain amplifier 88, and the amplified signal is output from the variable gain amplifier 88. The output of the variable gain amplifier 88 is converted from analog to digital by the A / D converter 89, and the digital signal is input to the controller 84.

  As described above, digital signals representing the light amounts in the double gate transistors 20, 20,... Are sequentially input to the controller 84. The controller 84 records the output of the A / D converter 89 in the memory 86, whereby the light amount distribution along the light receiving surface of the solid-state imaging device 10 is recorded in the memory 86 as two-dimensional image data.

  After inputting the image, the controller 84 turns off the excitation light irradiation device 81 and causes the output device 85 to output an image according to the image data recorded in the memory 86.

  According to this embodiment, the output of the drain driver 73 is subtracted by the subtractor 87 and further amplified by the variable gain amplifier 88, so that the maximum value of the output range of the variable gain amplifier 88 is the A / D converter 89. The minimum value of the output range of the variable gain amplifier 88 becomes equal to or greater than the lower limit value of the input dynamic range of the A / D converter 89 as well as the upper limit value of the input dynamic range. Therefore, the output resolution of the A / D converter 89 can be utilized to the maximum extent. In other words, if the resolution of the A / D converter 89 is 8 bits, almost all 256 gradations can be used as data. Accordingly, there is an advantage that the difference between the background noise level and the absolute value of the signal is increased.

  Therefore, a difference (contrast) between light and dark between a portion that emits fluorescence and a portion that does not emit fluorescence in the image input from the A / D converter 89 to the controller 84 increases. In this case, it is easy to specify a fluorescent part from the output image. That is, it is easy to specify the probe DNA spot 60 complementary to the fluorescently labeled DNA.

The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
In the above embodiment, the solid-state imaging device 10 using the double gate transistors 20, 20,... As a photoelectric conversion element has been described as an example, but the present invention is applied to a solid-state imaging device using a photodiode as the photoelectric conversion element. May be. Solid-state imaging devices using photodiodes include CCD image sensors and CMOS image sensors. In a CCD image sensor, photodiodes are arranged in a matrix on a substrate, and around each photodiode, a vertical CCD and a horizontal CCD for transferring an electrical signal photoelectrically converted by the photodiode. Is formed. In a CMOS image sensor, photodiodes are arranged in a matrix on a substrate, and a pixel circuit for amplifying an electrical signal photoelectrically converted by the photodiodes is provided around each photodiode. Yes.

  When the solid-state imaging device 10 is a CCD image sensor or a CMOS image sensor, it is a matter of course that the circuit configuration of the drive circuit 70 is changed to one suitable for the CCD image sensor or the CMOS image sensor. Since the drive circuit for the CCD image sensor and the CMOS image sensor is well known, description thereof is omitted here.

It is the perspective view which showed the biopolymer analysis chip | tip and the irradiation apparatus. It is the top view which showed a part of biopolymer analysis chip. It is the top view which showed the pixel of the solid-state imaging device. It is IV-IV arrow sectional drawing. It is drawing which showed the solid-state imaging device and its peripheral circuit. It is the chart which showed transition of the signal of a solid imaging device. It is the block diagram which showed roughly the structure of the biophotopolymer analysis assistance apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solid-state imaging device 20 Double gate transistor 60 Spot 70 Drive circuit 80 Biopolymer analysis support apparatus 82 Memory | storage device 84 Controller 87 Subtractor 88 Variable gain amplifier 89 A / D converter

Claims (9)

A solid-state imaging device;
A plurality of types of spots made of known biopolymers and scattered on the light receiving surface of the solid-state imaging device,
A drive circuit that drives the solid-state imaging device and outputs a signal corresponding to the amount of light received by the pixels of the solid-state imaging device;
A subtractor that subtracts the output of the drive circuit and outputs the difference;
An amplifier for amplifying the output of the subtractor;
An A / D converter that quantizes the output of the amplifier,
The subtractor aligns the minimum value of the output range of the drive circuit with the lower limit value of the input dynamic range of the amplifier,
The biopolymer analysis support apparatus, wherein the amplifier adjusts an output range of the subtractor to fall within an input dynamic range of the A / D converter.   2. The biopolymer analysis support apparatus according to claim 1, wherein the amplifier adjusts an output range of the subtractor to equalize an input dynamic range of the A / D converter. The amplifier is a variable gain amplifier;
The amplifier has a reference upper limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel in a state where light of maximum intensity is incident on the pixel of the solid-state imaging device, and light is incident on the pixel of the solid-state imaging device 3. The output of the subtracter is amplified by a gain corresponding to a difference from a reference lower limit voltage representing an output of the drive circuit by photoelectric conversion of the pixel in a state where the pixel is not operated. Biopolymer analysis support device. A storage device storing the reference upper limit voltage and the reference lower limit voltage;
The biopolymer analysis support apparatus according to claim 3, further comprising: a controller that reads the reference upper limit voltage and the reference lower limit voltage from the storage device and sets a gain of the amplifier based on a difference therebetween. .   The subtracter subtracts a reference lower limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel from the output of the drive circuit in a state where light is not incident on the pixel of the solid-state imaging device. The biopolymer analysis support apparatus according to claim 1 or 2. A storage device storing the reference lower limit voltage;
A controller that reads the reference lower limit voltage from the storage device and outputs the reference lower limit voltage to an inverting input terminal of the subtractor,
6. The biopolymer analysis support apparatus according to claim 5, wherein an output of the drive circuit is input to a non-inverting input terminal of the subtracter. The subtractor subtracts a reference lower limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel in a state where light is not incident on the pixel of the solid-state imaging device from the output of the drive circuit,
The amplifier is a variable gain amplifier;
The amplifier has a gain corresponding to the difference between the reference upper limit voltage and the reference lower limit voltage representing the output of the drive circuit by photoelectric conversion of the pixel in a state where light of maximum intensity is incident on the pixel of the solid-state imaging device The biopolymer analysis support apparatus according to claim 1, wherein the output of the subtracter is amplified by the step. A storage device storing the reference upper limit voltage and the reference lower limit voltage;
The reference upper limit voltage and the reference lower limit voltage are read from the storage device, the read reference lower limit voltage is output to the inverting input terminal of the subtractor, and based on the difference between the read reference upper limit voltage and the reference lower limit voltage. A controller for setting the gain of the amplifier,
8. The biopolymer analysis support apparatus according to claim 7, wherein an output of the drive circuit is input to a non-inverting input terminal of the subtracter.   The biopolymer analysis support apparatus according to claim 4, 6 or 8, wherein the storage device is mounted on the solid-state imaging device.

Images