1. Field of the Invention
The present invention relates to a DNA amplification device suitable for use when amplifying DNA (deoxyribonucleic acid).
2. Description of the Relevant Art
In general, the PCR method (polymerase chain reaction method) is known as a method for DNA amplification. The PCR method is a method where primers, an enzyme(s) and deoxyribonucleoside triphosphate, reacted with a DNA sample, are added to the DNA sample, whereupon the reaction solution is heated (or cooled down) by a heat cycle changed according to a pre-determined temperature pattern, and concurrently, where the sequential repetition of the heat cycle results in the amplification of the DNA.
Another DNA amplification device for realizing the PCR method is also known, for example, in the publication of Japanese Laid-Open Patent Application No. 2003-174863, which discloses a DNA amplification device equipped with a heating & cooling means established on an inorganic substrate, multiple reaction cells formed in a lattice pattern on the heating & cooling means, on the upper surfaces of which reaction cells is established a temperature measuring means, where electric heat conversion devices, in which a P-type peltiert element and an N-type peltiert element are regarded as one pair, are used as a heating & cooling means, and concurrently, where they are arranged in a lattice pattern at positions opposing the reaction cells.
For the cells (reaction cells) established in the DNA amplification device, multiple concave parts are normally formed & arranged at pre-determined intervals on the upper surface of a block board using a silicone wafer material or an aluminum material, the concave parts being directly constructed as cells (reaction cells), or in a construction in which the cells (tubes) are filled into the concave parts. With such construction, the block board where the cell group is formed functions as a processing block, with the bottom surface of the block board being heated or cooled down from the heating & cooling side of a thermo-module 3.
In the meantime, the heating & cooling means (thermo-module) where the peltiert elements are used is normally configured as shown in
However, in the case of using a processing block provided with this cell group for the DNA amplification device, there are problems that the following nonconformities may occur:
In this type of DNA amplification device, for pre-determined heating & cooling performance to a reaction solution, prompt temperature-rising performance or temperature-fall performance is especially required. However, this DNA amplification device cannot sufficiently respond to this required performance. In the DNA amplification device, as shown in
Further, the repetitive operation of the heat cycle may cause creeping at the soldered joints between the electrodes e . . . and the peltiert elements d . . . due to the modulus of longitudinal elasticity, the coefficient of the thermal expansion and a difference in thermal expansion, depending upon the temperature in the substrates 51 & 52, the electrodes e . . . and the peltiert elements d . . . , which creeping causes a thermal stress fraction, such as poor contact or breaking of wire, to the soldered joints. In particular, the generated direction of creeping is opposite between the heat radiation side (the substrate 52 side) and the heating & cooling side (the substrate 51 side). In other words, as shown by the outline arrows in
In the meantime, in order to inhibit the generation of creeping, it is effective to reduce the temperature variation at the soldered joints as much as possible. For this purpose, it is necessary to enlarge the volume of the heat sink 53 and to reduce the thermal resistance. However, there is a limit to enlargement of the volume of the heat sink 53. Normally, the thickness of a foundation 53b of the heat sink 53 is established at 10-15 [mm] from the viewpoint of reducing the thermal resistance and enhancing the rigidity, at the same time, preventing a warp (curvature) of the foundation 53b. Even in this case, the temperature variation of the soldered joints is approximately 5-10 [° C.], and the temperature variation at the soldered joints cannot be sufficiently inhibited, and the At the same time, it causes great enlargement of the entire thermo-module 3. In addition, in the case that the multiple thermo-modules 3 are scattered and arranged, the temperature greatly varies between each thermo-module 3, so even DND amplification to all cells cannot be performed.
The objective of the present invention is to provide a DNA amplification device that enables the prompt temperature-rising and temperature-falling controls, and that realizes the flexible and accurate temperature control, where the reduction of the duration in one process enables the improvement of the process efficiency and the power saving properties.
Another objective of the present invention is to provide a DNA amplification device where excellent thermal responsiveness is secured and the temperature variation on the heat radiation side of the thermo-modules is reduced, and where the reduction of the stress added to the peltiert elements comprising the thermo-module prevents thermal stress fracture at the thermo-module(s), enhancing durability (life expectancy).
Another objective of the present invention is to provide a DNA amplification device where the high quality of a processing block that has cells which can contain a reaction solution including a DNA sample, can be easily realized, and where the accuracy and stability of physical effects can be secured.
Another objective of the present invention is to provide a DNA amplification device where the uniform heat distribution enables the reducing variation of temperatures between each cell, and where the variance or shift of positions upon assembly or operation of each cell can be reduced.
In order to accomplish these objectives, the present invention is characterized by the fact that, in a DNA amplification device equipped with a processing block provided with cells that can contain a reaction solution including a DNA sample, a thermo-module(s) using peltiert elements for heating and cooling the processing block, and a controller that controls the electrification at least to the thermo-module(s); the processing block is comprised of a base constructed by adhering an upper substrate formed with a metal material and a lower substrate formed with a metal material or a ceramic material, and the cells supported by this base, the cells being secured to the upper substrate and/or the lower substrate via at least cell positioners established in the upper substrate for positioning the cells. At the same time, at least the thickness of regions situated under the cells in the lower substrate is selected to be 1.0 [mm] or thinner, and, the thermo-module(s) comes into contact with the lower surface of the base.
Further, the present invention is characterized by the fact that the processing block is comprised of a substrate formed with a metal material and the cells supported by the substrate; the cell positioners formed with a cylinder burling, where the protrusion upward from a pre-determined position results in fitting into the lower side of an outer circumferential surface of the cell, respectively, are established; the cells are fitted into the cell positioners, and respectively secured, with the thermo-module(s) coming into contact with the lower surface of the substrate. At the same time, slits for warp absorption, which are situated cross-wise to an end edge of the substrate, and are formed with a pre-determined length, are established along the end edge at a pre-determined intervals in the end edge.
In addition, the present invention is characterized by the fact that the processing block is comprised of a substrate formed with a metal material and the cells supported by the substrate; the cell positioners formed with a cylinder burling, where the protrusion upward from a pre-determined position results in fitting into the lower side of an outer circumferential surface of the cell, respectively, are established, with the cells being fitted into the cell positioners, and respectively secured, the thermo-module(s) coming into contact with the lower surface of the substrate. At the same time, a retainer plate that has control holes engaged or joined with the upper side of each cell, and corresponding to the position of each cell, respectively, is established.
Preferred embodiments relating to the present invention are described hereafter, with reference to the drawings. The present invention is not limited to the attached drawings which are provided for easily understanding the present invention. Further, detailed descriptions of the well-known portions are omitted in order to avoid ambiguity.
First, the construction of a DNA amplification device 1 relating to the present invention is described hereafter with reference to
In
In the meantime, a surface 15s of a heat radiation copper board 15 comes into contact with a surface at the heat radiation side 3r in each thermo-module 3 . . . In this case, thermal conduction grease is interposed between the surface at the heat radiation side 3r . . . in the thermo-module 3 . . . and one surface 15s of the heat radiation copper board 15, and each thermo-module 3 . . . and the heat radiation copper board 15 are secured using a fixture, such as a screw.
The entire heat radiation copper board 15 is integrally formed with a copper material, and act the same time, it is formed to be a plate with a uniform thickness. In this case, the thickness of the heat radiation copper board 15 is 4 [mm] or thicker, preferably selected to be within the range of 5-8 [mm]. Furthermore, in the case that the thickness is less than 4 [mm], the thermal diffusivity and the heat capacity become insufficient.
Further, a surface at the opposite side from the one surface 15s of the heat radiation copper board 15 is a heat radiation surface 15r, in which is installed and one, two or more heat sinks 32. [Each] heat sink 32 . . . has a foundation 32b that has an adherence surface 32bs . . . adhered to the heat radiation surface 15r, and many heat radiation fins 32f . . . that protrude vertically from a surface, which is opposite to this adherence surface 32b . . . , and a whole is integrally formed with an aluminum material. In this case, for the thickness of the foundation 32b . . . , approximately 2-3 [mm] of thickness that can maintain the heat radiation fins 32f . . . is sufficient. The thickness of the foundation 53b in the above-mentioned general heat sink 53 is normally established to be approximately 10-15 [mm] from the viewpoints of reducing the thermal resistance, enhancing rigidity and preventing warpage (curvature) of the foundation 53b. However, in the present embodiment, the heat radiation copper board 15 functions for reducing the thermal resistance, enhancing the rigidity. At the same time, preventing a warp of the foundation 32b . . . for the thickness of the foundation 32b in the heat sink 32 . . . , approximately 2-3 [mm] of thickness is sufficient as mentioned above.
One, two or more blast fans 33 . . . are arranged opposing each heat sink 32. enabling air-cooling of each heat sink 32 . . . by [each] blast fan 33 . . . , and this heat sink 32 . . . and the blast fan 33 . . . comprise an air-cooling device 34 (cooling means 16), respectively. In addition, the symbol 4 indicates a controller, and each blast fan 33 . . . and each of the above-mentioned thermo-module(s) 3 . . . are connected to this controller 4, respectively. With this connection, the controller 4 performs an electrification control to the thermo-module(s) 3 . . . . At the same time, performs the operation control to the blast fan(s) 33 . . .
On the other hand, a processing block 2 is installed to the surface(s) on the heating & cooling side 3s . . . in the thermo-module(s) 3, resulting in a structure where the thermo-module 3 . . . is interposed between the heat radiation copper board 15 (the heat sink 32 . . . ), arranged at the lower side, and the processing block 2, which in turn is arranged on the upper side, as shown in
The processing block 2 is a major component of the present embodiment, and is equipped with a base 5, constructed by adhering an upper substrate 6 and a lower substrate 7 formed with a metal material M, respectively, and cells C supported by the base 5. In this case, the entire upper substrate 6 is formed to be rectangular with a thin plate material made from a copper material (such as, oxygen free copper) selected to be 0.2 [mm] of thickness Lu as shown in
In the meantime, the entire lower substrate 7 is formed to be rectangular with a thin plate material formed with a copper material (such as, oxygen free copper) in a thickness of 0.2 [mm] Ld, as shown in
In addition, slits 14 . . . for warp absorption, formed cross-wise to the end edge 5e from the end edge 5e, and formed with a pre-determined length, are established in the base 5 along the end edge 5e at pre-determined intervals. In this case, the width of the [each] slit 14 is selected to be 0.1 [mm] or thicker, and the length is selected to be approximately 5-15 [%] of the length of one side of the end edge 5e. At the same time, the slits 14 are situated in between each of the cell positioners 6s . . . , respectively. Furthermore, the slits 14 . . . , as shown in
Each slit 14 . . . functions as follows:
In the heating mode, the lower substrate 7, which makes contact with the thermo-module(s) 3 . . . , is heated, with the heat being conducted to the below-mentioned cells C . . . . On this occasion, the heat is radiated from the external surface of the cells C . . . and the upper substrate 6 to the air outside, slightly lowering the surface temperature of the heat radiation region is slightly lowered, with potential deformation to warp the end edge from the upper substrate 6 upward. However, normally, since the upper surface of the upper substrate 6 is pressed onto the thermo-module(s) 3 by a heat-insulating material, such as rubber or resin, [coating] the outside of the cells C . . . , deformation occurs expanding toward the plane direction of the upper substrate 6. The establishment of the slits 14 . . . results in the absorption of the deformation expanding toward the plane. At the same time, there is an effect to reduce the temperature difference between the center region of the base 5 and the end edge 5e side. In the case of not establishing the slits 14 . . . , the temperature difference between the center region of the base 5 and the end edge 5e side is approximately 3-4 [° C.]. However, this has been improved to 1-1.5 [° C.] in the case of establishing the slits 14 . . . Consequently, establishing the slits 14 . . . enables the effective absorption of warp which may occur to the base 5 associated with the temperature variation upon operation, the securing of the accuracy and stability of the physical effects in the processing block 2, and the additional contribution to the improvement of durability.
In the meantime, as shown in
Furthermore, when installing the processing block 2 onto the surface(s) on the heating & cooling side 3s in the thermo-module(s) 3 . . . , the thermal conductive grease intervenes between the lower surface of the base 5 and the surface at the heating & cooling side 3s in the thermo-module(s) 3 . . . , and each thermo-module 3 . . . and the base 5 are secured using a fixture, such as a screw.
In processing block 2 endowed with the above construction, the heat capacity in the processing block 2 itself and an effect of the coefficient of thermal expansion on deformation, such as a warp, can be reduced, enhancing thermal conductivity, making it possible to promptly control temperature-rising and temperature-falling, realizing flexible and accurate temperature control can be realized, enabling a reduction of duration in one process with the improvement of the process efficiency and the power saving properties. Further, since the excellent thermal responsiveness at the processing block 2 results in reduction of the temperature variation at the heat radiation side of the thermo-module(s) 3 . . . , the thermal stress fracture at the thermo-module(s) 3 . . . can be prevented, and the durability (life expectancy) can be enhanced. Further, the stress added to the peltiert elements d . . . comprising the thermo-module(s) 3 . . . can be reduced, with improved durability. In addition, if the base 5 is constructed by adhering the upper substrate 6 and the lower substrate 7 formed with the metal material M, and at least the thickness Ld of the regions XC . . . situated under the cells C . . . in the lower substrate 7 is formed to be 0.1-0.5 [mm]. At the same time, the cells C . . . are secured to the upper substrate 6 and/or the lower substrate 7, enabling the obtainment of processing block 2 with high quality.
Processing block 2 can also be modified and used as follows:
In the above-mentioned embodiment, the lower substrate 7 is formed using a copper material. However, it can also be formed using a ceramic material E. For the ceramic material E, alumina (Al2O3), alumina nitride (AlN, silicon nitride (Si3N4) generally are utilized, and the thickness Ld is selected to be 0.3-1.0 [mm] (preferably, 0.6-0.7 [mm]). Further, for the adhesion to the upper substrate 6, a silicon material-base adhesive, which excels in the thermal conductivity, can be used. Furthermore, in the case of forming the lower substrate 7 using the ceramic material E, the above-mentioned slits 14 . . . become unnecessary.
Even though using this ceramic material E [for the lower substrate 7] causes a slight slow-down in the promptness of the temperature control because its thermal conductivity is smaller than that of the copper material, there are advantages such that the deformation of the upper substrate 6 due to the expansion (or contraction) upon the temperature-rising or temperature-tailing can be better prevented, and the uniformity of the temperature at each cell C . . . can be enhanced. At the same time, the improvement of following properties relating to the deformation of the upper substrate 6 results in it becoming difficult [for the lower substrate 7] to be exfoliated from the upper substrate 6.
In addition, it is also possible to construct the processing block 2 without using the lower substrate 7. In this case, since the lower substrate 7 is not used, only the upper substrate (substrate) 6 shown in
Even though using only the substrate 6 causes a slight reduction in the stability of a partial thermal contact with the thermo-module(s) 3 . . . , the heat capacity in the processing block 2 can be reduced. At the same time, the thermal conductivity can be additionally enhanced, with the advantage that more prompt (faster) temperature-rising control and temperature-falling control can be realized.
How to use the DNA amplification device 1 relating to the present embodiment and its operation are explained hereafter, with reference to
First, the controller 4 is provided with a sequence control function for the purpose of controlling the electrification of the thermo-modules 3 . . . in order to obtain the temperature pattern F shown in
Further, the controller 4 controls the blast fan(s) 33 . . . to be the operation mode. Furthermore, as the occasion demands, the blast fan(s) 33 . . . can be controlled using an inverter.
In the meantime, a reaction solution where primer, an enzyme(s) and deoxyribonucleoside triphosphate, which are reacted with a DNA sample, are respectively added to the DNA sample, is contained within the cells C . . . . Then, in the controller 4, first, electrification-controls the thermo-module(s) 3 . . . , and heating is performed at 94 [° C.] for T1 [sec] (for example, 15 [sec]), causing the dissociation of the DNA with a double helix structure. Next, the thermo-module(s) 3 . . . are electrification-controlled, and are cooled down to 50 [° C.]. At the same time, once the temperature reaches 50 [° C.], it is maintained at 50 [° C.] for T2 [sec] (for example, 15 [sec]). This causes the binding of the primers to a specific region of the DNA (annealing). Next, the thermo-module(s) 3 . . . is electrification-controlled, and heated to 72 [° C.]. At the same time, once the temperature reaches 72 [° C.], it is maintained at 72 [° C.] for T3 [sec] (for example, 30 [sec]). These operations result in the synthesis of a complementary strand to a specific gene bound with the primers by the enzyme. The above-mentioned operations are regarded as a single heat cycle, the repetition of which dozens of times (for example, 30 times) enables amplification processing of the DNA. On the other hand, when the DNA amplifying processing is finished, as shown in
In this case, during the heating operation, the processing block 2 is heated by the heating & cooling side 3s of the thermo-module 3, and the heat radiation side 3r is cooled down. At the same time, during the cooling operation, the processing block 2 is cooled down by the heating & cooling side 3s of the thermo-module 3, and, the heat radiation side 3r is heated. The quantity of heat on the heat radiation side 3r is radiated via a heat radiation copper board 15, the quantity of heat radiation becoming the sum of the quantity of heat deprived from the processing block 2 and the quantity of heat based on the input electric power for the cooling effect produced by the thermo-module(s) 3 itself. Although the heating & cooling capability (heating & cooling speed) is also greatly affected by the heat radiation on the heat radiation side 3r, the excellent thermal diffusivity and great heat capacity by the heat radiation copper board 15 enables controlling temperature variation at the soldered joints between the peltiert elements d . . . in the thermo-module(s) 3 . . . and the electrodes [e . . . ] to be approximately 3 [° C.] or less. Therefore, the thermal stress fraction, such as poor contact or breaking of wire, at the soldered joints occurring due to thermal stress (creep) can be prevented, and the durability (life expectancy) of the thermo-module(s) 3 . . . can be dramatically enhanced.
Further, according to the DNA amplification device 1 relating to the present embodiment, excellent heat radiation by the heat radiation copper board 15 results in the discharge from the heat radiation side 3r in a thermo-module 3 filled with heat. At the same time, in addition, the structure of the processing block 2 enables the enhancement of the heating performance and the cooling performance, as a result of which the temperature-falling period Td and the temperature-rising periods Tf and Ts in
In addition, even in the case of scattering and arranging multiple thermo-modules 3 . . . , because the variation of the temperature between each thermo-module 3 . . . is reduced, uniform DNA amplification in all of the cells C . . . can be realized.
A modified embodiment of the processing block 2 and cooling means 16 is explained hereafter, with reference to
In this case, for the substrate 6 and the retainer plate 17, a copper material with 0.1-0.5 [mm] of thickness, preferably 0.3 [mm], is used, respectively. Further, the control holes 17s . . . in the retainer plate 17 are respectively formed from a hole where the upper end of the cell C . . . is fitted. Furthermore, on the outer circumferential surface of the illustrated cell C, a ring-state flange Csf that protrudes outward at a position slightly lower from the top end of the cell C, and for this flange Csf, as shown in
According to the present modified embodiment, since it has construction that the substrate 6 supports each cell C . . . and the thermo-module(s) 3 . . . comes into contact with the lower surface of this substrate 6, even though the stability of a partial thermal contact to the thermo-module(s) 3 . . . is slightly lowered, the heat capacity in the processing block 2 can be reduced. At the same time, thermal conductivity can be additionally enhanced, and prompter (faster) temperature-rising control or temperature-falling control can be realized.
Further, since the retainer plate 17 is established, warp of the substrate 6 can be prevented. In other words, when the temperature is high (90 [° C.] or higher), the cells C positioned at the outer edge side of the substrate 6 lean [outward] relative to the cell(s) C situated in the center by an angle R as a cell Co shown with a virtual line in
Furthermore, the case where the illustrated retainer plate 17 is fitted into the upper end of [each] cell C . . . has been shown, and it can be designed such that the retainer plate 17 is seized on the outer circumferential surfaces in the middle of the vertical direction of the cells C . . . , as [another] retainer plate 17e shown with the virtual line in
Therefore, according to the present modified embodiment, since there is a connection between each cell C with the retainer plate 17, the variation of the temperature between each cell C. can be reduced due to the uniformalization of heat dissemination. At the same time, the variation and fluctuation of the position of each cell C . . . upon the assembly or operation can be reduced. Therefore, the reduction of a pitch Lp in between each cell C . . . shown in
As described above, the embodiments have been explained in detail. However, the present invention is not limited to these embodiments, but the construction of the details and the methods generally can be optionally modified within the scope of the concept of the present invention. At the same time, addition and deletion are also applicable as the circumstances demand. For example, as the metal material M, a copper material is most preferable. However, this does not exclude the utilization of other metal materials M, such as aluminum. Further, the DNA amplification device 1 in the present invention includes an enzyme reaction device, as well. In addition, in
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2005-013773 | Jan 2005 | JP | national |
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