Abstract:
Provided are a temperature control method and apparatus for driving a polymerize chain reaction (PCR) chip. In the temperature control apparatus, which is for a polymerize chain reaction chip, PCR chips receive electric power from the outside and generating heat to maintain a predetermined temperature and for outputting actual temperature information to the outside. electric power supply units supply electric power to the PCR chips according to input control signals, and a controller generates the control signals based on control information including pre-established control temperature and control time information and the actual temperature information supplied from the PCR chips in order to supply the control signals to the electric power supply units. In the present invention, it is possible to examine various kinds of DNA at the same time because the temperature control apparatus controls the temperatures of DNA samples at the same time.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a temperature control method and apparatus, and more particularly, to a temperature control method and apparatus for driving a polymerize chain reaction (PCR) chip.  
           [0003]    2. Description of the Related Art  
           [0004]    A conventional apparatus for amplifying deoxyribonucleic acid (DNA) by using a PCR amplifies a PCR at the same temperature cycles by binding more than 14 small tubes having a content of 0.5 ml or 0.2 ml. The conventional apparatus has an advantage of analyzing the samples of a plurality of patients at the same time; however, it is difficult to examine various kinds of DNA at the same time because temperature conditions for maximizing the amplification of DNA are different for each DNA. In addition, the sample amount required for the experiment is at least 0.2 ml which is as much as 55 times of the capacity of a chamber in a micro PCR chip according to the present invention, which is 3.6 μl. Accordingly, the conventional method needs to extract a large amount from the samples of the patients. In addition, since large amounts of carcinogenic materials, which are added for the experiment, are used in the conventional apparatus, environmental contamination occurs.  
         SUMMARY OF THE INVENTION  
         [0005]    To solve the above-described and related problems, it is an objective of the present invention to provide a temperature control method and apparatus for a polymerize chain reaction (PCR) chip.  
           [0006]    To accomplish the objective of the present invention, there is provided a temperature control apparatus for a polymerize chain reaction chip, the temperature control apparatus comprising: PCR chips for receiving electric power from the outside and generating heat to maintain a predetermined temperature and for outputting actual temperature information to the outside; electric power supply units for supplying electric power to the PCR chips according to input control signals; and a controller for generating the control signals based on control information including pre-established control temperature and control time information and the actual temperature information supplied from the PCR chips in order to supply the control signals to the electric power supply units.  
           [0007]    Preferably, the temperature control apparatus further includes: a selector for receiving a first selection signal for selecting the PCR chip to be controlled and the control signal from the controller, in order to select the electric power supply unit for supplying the electric power to the PCR chip to be controlled and supply the control signal to the selected electric power supply unit; and a multiplexer for receiving a second selection signal for selecting one of the PCR chips from the controller and supplying the actual temperature information on a predetermined PCR chip to the controller according to the second selection signal.  
           [0008]    Preferably, one PCR chip in the temperature control apparatus includes: a heater for receiving electric power from the electric power supply unit to generate heat; and a temperature sensor for measuring the temperature of the PCR chip and outputting the temperature to the outside.  
           [0009]    Preferably, the temperature control apparatus further includes: an input/output (I/O) unit for receiving control information including the control temperature and time information from a user, in order to supply the control information to the controller and outputting the control result of the temperature of a predetermined PCR chip to the outside according to the control information.  
           [0010]    To accomplish the objective of the present invention, there is provided a temperature control method for a PCR chip, the method comprising: (a) receiving control information including the control temperature and time of a PCR chip; (b) generating a control signal for the PCR chip to maintain the control temperature for the predetermined time; and (c) controlling the temperature of the PCR chip according to the control signal.  
           [0011]    Preferably, step (b) includes (b 1 ) generating a selection signal for selecting a PCR chip to be controlled by the control signal when a plurality of PCR chips are arranged, and in step (c), the temperature of the predetermined PCR chip is controlled according to the selection signal and the control signal.  
           [0012]    Preferably, the temperature control method further includes: (d) measuring the temperature of the PCR chip; and (e) repeating (b) when the actual temperature and the control temperature of the PCR chip are different.  
           [0013]    Preferably, step (e) includes: (e 1 ) generating information for selecting a predetermined PCR chip when a plurality of PCR chips are arranged; and (e 2 ) subsequently comparing the actual temperature of the selected PCR chip with the control temperature corresponding to the selected PCR chip to perform (b) when the actual temperature and control temperature are different.  
           [0014]    To accomplish the objective of the present invention, there is provided a recording medium readable in a computer, wherein a program for operating a method among the above methods is recorded. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The above objective and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:  
         [0016]    [0016]FIG. 1 is a functional block diagram illustrating a temperature control apparatus for a polymerize chain reaction (PCR) chip according to an embodiment of the present invention;  
         [0017]    [0017]FIG. 2 is a functional block diagram illustrating a PCR chip according to another embodiment of the present invention;  
         [0018]    [0018]FIG. 3 is a flowchart for explaining a temperature control method for a PCR chip according to still another embodiment of the present invention;  
         [0019]    [0019]FIG. 4 is a diagram illustrating a hardware configuration of a temperature control apparatus of a PCR chip of FIG. 1 according to yet another embodiment of the present invention;  
         [0020]    [0020]FIG. 5 is a diagram illustrating a hardware configuration of a PCR chip of FIG. 2 according to further another embodiment of the present invention;  
         [0021]    [0021]FIG. 6 illustrates a waveform of a platinum sensor voltage measured at an analog/digital (A/D) converter input terminal by using an oscilloscope according to still further embodiment of the present invention, in which the temperature of a predetermined PCR chip is controlled by using a PCR chip according to the present invention;  
         [0022]    [0022]FIG. 7 illustrates the waveform of a voltage in a platinum sensor obtained from a CPU according to the embodiment of FIG. 5;  
         [0023]    [0023]FIG. 8 illustrates the overshoot of a platinum heater temperature according to the embodiment of FIG. 5;  
         [0024]    [0024]FIG. 9 illustrates a normal state error of a platinum heater temperature according to the embodiment of FIG. 5; and  
         [0025]    [0025]FIG. 10 illustrates an amplified deoxyribonucleic acid (DNA) fluorescent image according to the embodiment of FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    [0026]FIG. 1 is a functional block diagram illustrating a temperature control apparatus for a polymerize chain reaction (PCR) according to an embodiment of the present invention. An input/output (I/O) unit  101  receives selection information, control temperature and time information for selecting a PCR chip to be controlled at a predetermined temperature for a predetermined time from the outside, and supplies the information to a controller  102 . In addition, the I/O unit  101  receives the control result information of the PCR chip, i.e., actual temperature information on the PCR chip, from the controller  102 , and provides the control result information on the PCR chip, i.e., actual temperature information on the PCR chip, to a user.  
         [0027]    The controller  102  generates a control signal based on the selection information, the control temperature and time information from the I/O unit  101 , and collects the actual temperature information on the PCR chip to be controlled in order to supply the information to the I/O unit  101 . In addition, the controller  102  generates a selection signal for selecting a predetermined PCR chip, whose temperature will be read out in order, to provide the selection signal to a multiplexer  106   
         [0028]    A selector  103  selects an electric power supply unit  1041 , or  1042 , . . . that provides electric power to the PCR chip to be controlled, according to the control signal from the controller  102 , and provides the control signal to the selected electric power supply unit  1041 , or  1042 , . . .  
         [0029]    The electric power supply units  1041 ,  1042 , . . . respectively supply electric power to predetermined PCR chips  1051 ,  1052 , . . . , which are respectively connected to the electric power supply units  1041 ,  1042 , . . . , based on the control signal from the selector  103 .  
         [0030]    The PCR chips  1051 ,  1052 , . . . respectively receive electric power from the electric power supply units  1041 ,  1042 , . . . and generate heat by using the electric power, thereby controlling the chip temperature. The PCR chips  1051 ,  1052 , . . . respectively measure their own temperatures and respectively supply the temperature values to the multiplexer  106 .  
         [0031]    The multiplexer  106  receives actual temperature information on the PCR chips  1051 ,  1052 , . . . from the PCR chips  1051 ,  1052 , . . . , and receives the selection signal for selecting one PCR chip from the controller  102  in order to provide the actual temperature information on the PCR chip selected by the selection signal to an analog/digital (A/D) conversion unit  107 .  
         [0032]    The A/D convertor  107  receives the actual temperature information on the PCR chip selected by the selection information from the multiplexer  106  in order to convert the actual temperature information into a digital signal, and supply the digital signal to the controller  102 .  
         [0033]    [0033]FIG. 2 is a functional block diagram illustrating a PCR chip according to one embodiment of the present invention.  
         [0034]    A heater  201  receives electric power from the outside to generate heat.  
         [0035]    A temperature sensor  202  measures the actual temperature of the heater  201  and outputs the temperature to the outside.  
         [0036]    [0036]FIG. 3 is a flowchart for explaining a temperature control method for a PCR chip according to one embodiment of the present invention. Control information, including temperature information and time information on a PCR chip, is input in step  301  in order to generate a control signal for controlling the temperature of the PCR chip according to the control information in step  302 . Thereafter, the PCR chip to be controlled is selected by the control signal to control the temperature of the PCR chip in step  303 . Next, the actual temperature of the PCR chip is measured in step  304  in order to compare the measured temperature with the control temperature in step  305 . When the temperatures are the same, the method proceeds to step  304 . When the temperatures are different, the method proceeds to step  302 .  
         [0037]    [0037]FIG. 4 is a diagram illustrating a hardware configuration of temperature control apparatus of a PCR chip of FIG. 1 according to one embodiment of the present invention. In the present invention,  128  CPR chips are used. When a constant current is applied to platinum sensors of the PCR chips, different voltages are generated at the both ends of the platinum sensors according to the temperatures of the PCR chips. The different voltages are processed and transferred to a CPU. The CPU converts the analog voltage information into digital information and compares the measured temperature of the PCR chip with a target temperature. If the measured temperature is higher than the target temperature, a heater included in the chip is turned off. In other case, the heater included in the chip is turned on.  
         [0038]    More specifically, a CPU  401  corresponds to the controller  101  of FIG. 1. In other words, the CPU  401  generates a control signal for controlling the temperature of a PCR chip to be controlled based on predetermined control temperature and time and information on the PCR chip. In the present invention, the control signal includes heater on/off signals supplied to photo MOSFETs  404001 ,  104002 , . . . corresponding to the electric power supply units  1041 ,  1042 , . . . of FIG. 1, and 4-bit address signals for selecting the PCR chip. The heater on/off signals are supplied to 8-bit latches  40301 , . . . ,  10316 , and the 4-bit address signals are supplied to the 8-bit latches  40301 , . . . ,  40316  through a decoder  402 . Accordingly, the decoder  402  and the 8-bit latches  40301 , . . . ,  40316  correspond to the selector  103  of FIG. 1.  
         [0039]    The latches  40301 , . . . ,  40316  select the PCR chip to be controlled by using the 4-bit address signals, and supply the heater on/off signal to the photo MOSFET  404001 , . . . ,  404128  that supplies electric power to the PCR chip to be controlled. The Photo MOSFET  404001 , . . . ,  404128  respectively supply electric power to the PCR chips  405001 , . . . ,  405128  according to the heater on/off signal, and the PCR chips  405001 , . . . ,  405128  respectively generate heat by using the supplied electric power. In addition, actual temperature information on the PCR chips is generated and respectively supplied to analog multiplexer  40601 , . . . ,  40608 .  
         [0040]    The analog multiplexer  40601 , . . . ,  40608  receive the selection signal for selecting the PCR chip, whose temperature will be read out, from the CPU  401  and receive the actual temperature information on the PCR chip to provide the actual temperature signal of the selected PCR chip to the CPU  401 .  
         [0041]    [0041]FIG. 5 is a diagram illustrating a hardware configuration of a PCR chip of FIG. 2 according to another embodiment of the present invention. Here, a PCR chip is formed of a platinum heater and a platinum sensor. In order to generate a fine constant current for measurement, a regulator ADP3301 having an output voltage error of 0.8% and a high performance op-amp MC33184 are used to generate a constant current of 4 mA, and the constant current is supplied to the platinum sensor. Here, a four-point probe method is used to measure the voltages generated in the platinum sensor. In this case, the voltages at the both ends of the platinum sensor are measured by using an instrumentation amplifier. In addition, a DC offset and an amplification rate of the voltages are controlled at an end circuit, and then, the voltages are supplied to analog multiplexers through an over voltage limiter formed of two diodes. A CPU recognizes the temperature of the PCR chip based on the supplied information and generates a control command by comparing the temperature of the PCR chip with the target temperature. In addition, the CPU switches an external electric power supplied to a heater by using a high-speed photo MOSFET, instead of a relay, to control the temperature of the PCR chip.  
         [0042]    More specifically, an electric power supply unit  501  is formed of an external electric power source  5011  and a photo MOSFET  5012  that receives an on or off signal from the outside to turn on or off the external electric power source  5011  and the electric power supplied to a platinum heater  5021 .  
         [0043]    Reference numeral  502  denotes a device is formed of a platinum heater  5021  and a platinum sensor  5022 . Here, the platinum heater  5021  converts the electric power supplied from the external electric power source  5011  into heat. The platinum sensor  5022  receives constant voltage and constant current to generate a voltage corresponding to the temperature of the platinum heater  5021  and outputs the temperature to the outside.  
         [0044]    Reference numeral  503  denotes a circuit that supplies the constant voltage and constant current to the platinum sensor  5022 , and measures the temperature of the platinum heater  5021  by comparing the output voltage of the platinum sensor  5022  corresponding to the temperature of the platinum heater  5021  with the input voltage, i.e., the constant voltage. Here, reference numeral  5031  denotes a regulator ADP3301 as a constant voltage circuit, reference numeral  5032  denotes op-amp MC33184 as a constant current circuit, and reference numeral  5033  denotes an amplifier for amplifying a difference between an input voltage and an output voltage. The actual temperature information on the platinum heater  5021 , which is measured in the circuit  503 , is output to an analog multiplexer.  
         [0045]    A PCR experiment using a temperature control apparatus for a PCR chip according to the above embodiment of the present invention will now be described. Here, plasmid deoxyribonucleic acid (DNA) is used as an amplifying sample, and a driving solution is formed by adding a buffering solution including primer, dNDP, salt, and DNA polymerize enzyme to a start sample. After filling a reaction chamber by flowing the driving solution into an inlet of a PCR chip, the inlet and outlet of the reaction chamber are sealed by using fine block and epoxy. The thermostatic control apparatus establishes temperature sections of 55° C., 72° C., and 95° C. and a maintenance time for 30 seconds, respectively.  
         [0046]    [0046]FIG. 6 illustrates a waveform of platinum sensor voltage measured at an A/D converter input terminal by using an oscilloscope according to still another embodiment of the present invention, and FIG. 7 illustrates a waveform of a voltage in a platinum sensor obtained from a CPU according to yet another embodiment of the present invention. As shown in FIGS. 6 and 7, the CPU truly recognizes the output values of the platinum sensor.  
         [0047]    [0047]FIG. 8 illustrates the overshoot of a platinum heater temperature according to still yet another embodiment of the present invention, and FIG. 9 illustrates a normal state error of a platinum heater temperature according to further another embodiment of the present invention. As shown in FIGS. 8 and 9, a temperature control apparatus according to the present invention can control a micro PCR chip while having a normal state error of plus or minus 0.4° C., an overshoot of less than 0.6° C., and an increasing speed of 6.8° C./sec. The above temperature control apparatus according to the present invention has a performance as good as the performance of a conventional product that amplifies a PCR by using tubes of 0.2 ml.  
         [0048]    [0048]FIG. 10 illustrates an amplified DNA fluorescent image according to still further another embodiment of the present invention. Here, clear amplified DNA bands are represented in the image of FIG. 10.  
         [0049]    The embodiments of the present invention can be embedded as computer programs that can be operated in a computer so that the embodiment of the present invention can be realized in a digital computer that operates the program by using a recording medium used in the computer.  
         [0050]    The recording medium used in the computer includes magnetic recording media, for example, ROM, floppy disks, and hard disks, optical recording media, for example, CD-ROM and DVD, and carrier wave, for example, transfer through the Internet.  
         [0051]    As a result, a plurality of DNA samples are simultaneously examined under different temperature conditions so that examination and analysis times can be reduced. In addition, only small amounts of samples are required for the examination, burden on patients can be reduced while reducing environmental contamination.  
         [0052]    In addition, a temperature control apparatus according to the present invention controls the temperature of a fine PCR chip so that the temperature is rapidly increased and decreased. In addition, the temperature of a reaction chamber can be precisely measured in a short time by using a platinum sensor attached under the chamber of the PCR chip, so that the temperature of the PCR chip can be precisely controlled.  
         [0053]    While this invention has been particularly shown and described with reference to preferred embodiments thereof, the preferred embodiments described above are merely illustrative and are not intended to limit the scope of the invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and equivalents thereof.