WO2002016544A1

WO2002016544A1 - Thermal cycler

Info

Publication number: WO2002016544A1
Application number: PCT/KR2000/000939
Authority: WO
Inventors: Gi-Young Jang; Jang-Seu Ki
Original assignee: Bionex, Inc.
Priority date: 2000-08-22
Filing date: 2000-08-22
Publication date: 2002-02-28
Also published as: AU2000270385A1

Abstract

Disclosed is a thermal cycler (1).The Thermal cycler (1) comprises a polymerase chain reaction (PCR) module (10) having a plurality of receiving grooves for receiving a plurality of microplates (12) in which biological or chemical samples are received; a base body (30) having a module receiving part formed on its upper area and receiving the PCR module (10) therein; and an upper cover (40) for covering an upper opening of the PCR module (10), wherein the microplate receiving grooves are inclined relative to a plane of PCR module (10). With this configuration, the thermal cycler (1) according to the present invention is capable of amplifying nucleic acids of the large number of samples in a compact area simultaneously under a constant temperature within a short period of time at desired angles.

Description

THERMAL CYCLER

Technical Field

The present invention relates in general to thermal cyclers, and more particularly, to a thermal cycler in which nucleic acids of a large number of samples can be amplified simultaneously. Background Art

A polymerase chain reaction (PCR) is a process for amplifying a desired DNA molecule in vitro by composing a certain site of the DNA molecule peculiarly in a repeated manner, thereby obtaining a large quantity of identically reproduced DNA molecules by means of a very small number of DNA molecules. In the PCR, the composition is performed by first mixing strands of the DNA to be reproduced as a polymeric material for the PCR, two or more primers, polymerases, single bases (dATP, dCTP, dGTP, dTTP) and reagents, and thereafter heating the mixture to the temperature required for reaction, i.e., to the temperature at which DNAs are denaturalized, to the temperature at which primers are annealed, and to the temperature at which DNAs are polymerized, and then heating and cooling them repeatedly. Through the denaturalization of DNAs, double-stranded DNAs are separated into single-stranded DNAs by heating the double-stranded DNAs at 90^°C to 98^°C. The higher the temperature is, the better they are separated into the single-stranded DNAs; however, the activity of the polymerases may be lowered. Considering this lowering, the denaturalization temperature is usually set 94 °C. Thereafter, primers are annealed at the temperature of 45^°C to 65°C and complementary couplings are induced to a template DNA after the temperature is increased sufficiently high to increase the activity of the polymerases, and finally the DNA molecules are polymerized.

Through the polymerase chain reaction, a specific site of DNA in vitro is amplified to 10⁵ to 10⁸ within a few hours of time. This amplified DNA can be used in a variety of experiments, and the results from the experiments can be used for several medical applications. The experiments in which the polymerase chain reaction can be used include, but not limited to, amplification of double-stranded DNAs cloned to be used as a probe, cloning of specific cDNAs from a small amount of mRNAs, DNA sequencing, inspection on mutation, detection of etiological viruses and bacteria, footprinting of genes, production of genes causing mutagenesis directed in a specific site, etc. As wide medicinal applications of the polymerase chain reaction, there are determination of human leukocyte antigen (HLA) , legal medicine, detection of genes from a certain person, detection of genes causing a cancer or cancers, detection of single nucleotide polymorphism, diagnosis of genetic diseases, and diagnosis of infective diseases.

Since the polymerase chain reaction was disclosed in US Patent Nos. 4,683,202, 4,683,195 and 4,889,818, and EPO Publication No. 258,071, there have been efforts to utilize the polymerase chain reaction in commercial applications. The first commercial thermal cycler was designed in Perkin-Elmer' s Cetus DNA thermal cycler developed in 1987.

Temperature which constitutes an essential factor in the polymerase chain reaction is controlled by a heating and cooling device built in a module, employing the system of Peltier which has been used in all types of thermal cyclers .

US Patent No. 5,601,141 discloses a high throughput thermal cycler wherein a large batch of sample plates can be put layer after layer, by conducting heat to the sample plates through a medium by means of a heat conductor. The products currently available in the market are "DNA Engine" made by M.J. Research and "MultiBlock System (MBS)" made by Hybaid Inc., etc. The DNA Engine combines an alpha module with plates containing polymerase samples, generating the polymerase chain reaction. A microtiter plate or microplate is used in singles or in pairs by connection. The alpha module can be combined in a various manner depending upon the kind of samples. The MBS is conducted by connecting at maximum 30 modules to an existing thermal cycler, thereby reacting a large amount of samples. The module therein has six heat sensors, by which an exact temperature is sensed and controlled by a computer. In the conventional thermal cyclers, however, in order to amplify a great large number of nucleic acids, single microplates have to be horizontally arranged in a single layer on the upper planar surface of the PCR module or stacked vertically, thereby making it difficult to control all the microplates under the same temperature in the rapid heating and rapid cooling processes of the microplates . Where there are generated areas having different temperatures in the microplates, it is difficult to detect malfunctioned areas in the thermal cycler and remedy them. Additionally, a number of microplates have to be rapidly heated or cooled over the whole area, the time in heating and cooling the plates is more consumed than using the single microplates. Thus, in the case of the polymerase chain reaction requiring for repetitive cooling or heating over 50 times, three to four hours or more would be consumed.

DISCLOSURE OF THE INVENTION The present invention has been made keeping in mind the above-described shortcomings, and an object of the present invention is to provide a thermal cycler in which a large number of samples of nucleic acids can be amplified simultaneously at the same temperature.

This and other objects of the present invention may be achieved by the provision of a thermal cycler comprising a polymerase chain reaction (PCR) module having a plurality of receiving grooves for receiving a plurality of microplates in which biological or chemical samples are received; a base body having a module receiving part formed on its upper area and receiving the PCR module therein; and an upper cover for covering an upper opening of the PCR module, wherein the microplate receiving grooves are inclined relative to a plane of the PCR module. Preferably, the inclination angle of the microplate receiving grooves of the PCR module is approximately 10° to 90^° .

Also preferably, the PCR module is rotatable with a predetermined angle within the module receiving part of the base body. It is desirable that the lower part of the PCR module is protruding in hemispherical shape, whereas the module receiving part of the base body is formed in a hemispherical shape to correspond with the protruding part of the PCR module.

Desirably, the PCR module is rotatable with approximately 0° to 45^° within the module receiving part of the base body.

A cartridge is received in the microplate receiving grooves so that the cartridge closely coupled to the' microplate can easily transmit heat between the microplate receiving grooves and the microplates.

Preferably, the normal distance between opposite inner faces of each microplate receiving grooves is approximately 5 mm to 30mm.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view schematically showing a thermal cycler according to the present invention;

Fig. 2 is a sectional view of a PCR module taken along line II-II of Fig. 1; Fig. 3 is a sectional view showing the status that a microplate and a cartridge are combined in the PCR module;

Fig. 4 is a top plan view of the PCR module of Fig. 3; Fig. 5a is an exploded perspective view of the microplate and the cartridge;

Fig. 5b is a perspective view showing an assembling status of the microplate and the cartridge; and

Fig. 6 is a view schematically showing a rotation status of the PCR module within a body.

MODES FOR CARRYING OUT THE INVENTION Fig. 1 is a perspective view schematically showing a thermal cycler according to the present invention. As illustrated therein, the thermal cycler 1 is comprised of a PCR module 10 receiving therein a microplate 12 in which samples for the polymerase chain reaction are accommodated, a base body 30 on which the PCR module 10 is mounted, and an upper cover 40 covering the upper opening of the PCR module 10. On the upper face of the PCR module 10 are installed a plurality of temperature sensors 18 sensing the inner temperature of the PCR module 10.

As described above, on the lower part of the PCR module 10 is provided the base body 30 on which the PCR module 10 is mounted. On the upper of the base body 30 is formed a hemispherical module receiving part 32 receiving the PCR module 10 therein.

On one side of the base body 30 is provided a control panel 34 with a prerecorded PCR program, for displaying temperatures transmitted from the temperature sensors 18 of the PCR module 10, and manipulating heating and cooling devices (not shown) for heating and cooling the PCR module 10.

Referring again to Fig. 1, the upper cover 40 covering the top part of the PCR module 10 is provided over the top of the PCR module 10. Between the inner side of the upper cover 40 and the top part of the PCR module 10 is provided a support plate 42 of a planar shape. When the upper cover 40 covers the top part of the PCR module 10, the PCR module support plate 42 is closely contacted to the top face of the PCR module 10. The support plate 42 is preferably made of silicon. The upper cover 40 is provided with a locking device 44 having a screwed-shape end, allowing the PCR module support plate 42 to be closely contacted to the top face of the PCR module 10 by adjusting the screw of the locking device 44 when the upper cover 40 covers the upper face of the PCR module 10.

The reference numerals 12 and 14 of Fig. 1 denote a microplate and a cartridge respectively mounted on the PCR module 10, which will be described later in more detail .

Referring to Fig. 2, in the upper area of the PCR module 10 are formed a plurality of microplate receiving grooves 20 in which the microplates 12 and the cartridges 14 are received. The receiving grooves 20 are formed in parallel with predetermined intervals, being inclined relative to the plane of the PCR module 10. Preferably, the normal distance between opposite inner faces of the receiving groove 20 is approximately 5 mm to 30 mm, and the inclination angle (α) of the receiving groove is approximately 10° to 90° . Between the microplate receiving grooves 20 of the PCR module 10 is provided a heating and cooling part 16, for serving to heat and cool the cartridges 14 closely coupled to the microplates 12 by means of a heating and cooling device (not shown) .

On the lower area of the PCR module 10 is formed a hemispherical protruding part 10a. The protruding part 10a of the PCR module 10 is received in the hemispherical module receiving part 32 formed in the upper area of the base body 30. The protruding part 10a is rotatable within the module receiving part 32. As shown in Fig. 6, it is preferable that the rotational angle (β) of the PCR module 10 within the module receiving part 32 of the base body 32 is approximately 0° to 45° .

Figs. 3 and 4 show that the plurality of microplates 12 and the cartridges 14 are received within the microplate receiving grooves 20 of the PCR module 10. Fig. 5a shows the microplate 12 having a plurality of conical sample receiving holes 12a in its lower part, allowing the samples to be received therein, and the cartridge 14 having a plurality of concave holes 14 corresponding to the conical holes 12a of the microplate 12. In one side end of the cartridge 14 is formed a knob 14b allowing the cartridge 14 to be easily received in or removed from the receiving holes 20 of the PCR module 10. As illustrated in Fig. 5b, the microplate 12 and the cartridge 14 are combined with each other by causing the sample receiving holes 12a to be close to the concave holes 14a of the cartridge 14. The closely combined microplate 12 and cartridge 14 is installed within the microplate receiving groove 20 as seen in Figs. 3 and 4. With this configuration, the microplate 12 and the cartridge 14 are closely combined with each other after the samples are put into the plurality of sample receiving holes 12a, and then the microplate 12 closely coupled to the cartridge 14 is installed in the microplate receiving groove 20 of the PCR modules 10. Subsequently, after covering the top part of the PCR module 10 with the upper cover 40, the heating and cooling device within the PCR module 10 are operated by manipulating the control panel 34 according to the prerecorded PCR program therein. As the heating and cooling part 16 of the PCR module 10 are heated and cooled by the heating and cooling device, the cartridges 14 inserted into the microplate receiving grooves 20 are heated and cooled accordingly. Heat is transmitted to the microplates 12 closely combined with the cartridge 14, and is subsequently transmitted to the samples received in the conical sample receiving holes 12a within the microplates 12, thereby allowing the samples to be polymerized. By inclinedly installing the microplate receiving grooves 20 of the PCR module 10, the microplates 12 are closely arranged within a small space, and a large number of microplates 12 can be loaded within a short period of time. Since heat is transmitted to the upper and lower parts of the microplates 12 simultaneously, the temperature of the microplates 12 can be maintained in a constant manner. This may result in reducing a production cost of the PCR module 10 and the energy consumption thereof. Additionally, by allowing the PCR module 10 to be rotatable, the angle formed by the microplate 12 within the PCR module 10 and the horizontal plane can be adaptively adjusted and the microplates 12 can be installed at any desired angle.

As described ' above, a thermal cycler according to the present invention is advantageously able to amplify a large number of samples of nucleic acids simultaneously within a small space at a desired angle in a short period of time.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

WHAT IS CLAIMED IS:

1. A thermal cycler comprising: a polymerase chain reaction (PCR) module having a plurality of receiving grooves for receiving a plurality of microplates in which biological or chemical samples are received; a base body having a module receiving part formed on its upper area and receiving the PCR module therein; and an upper cover for covering an upper opening of the PCR module, wherein the microplate receiving grooves are inclined relative to a plane of the PCR module.

2. The thermal cycler according to claim 1, wherein the inclination angle of the microplate receiving grooves of the PCR module is approximately 10^° to 90° .

3. The thermal cycler according to claim 1 or 2, wherein the PCR module is rotatable with a predetermined angle within the module receiving part of the base body.

4. The thermal cycler according to claim 3, wherein the lower part of the PCR module is protruding in hemispherical shape, whereas the module receiving part of the base body is formed in a hemispherical shape to correspond with the protruding part of the PCR module.

5. The thermal cycler according to claim 4, wherein the PCR module is rotatable with approximately 0° to 45° within the module receiving part of the base body.

6. The thermal cycler according to claim 1, wherein a cartridge is received in the microplate receiving grooves so that the cartridge closely coupled to the microplate can easily transmit heat between the microplate receiving grooves and the microplates.

7. The thermal cycler according to claim 6, wherein the normal distance between opposite inner faces of each microplate receiving grooves is approximately 5 mm to 30 mm.