Patent Publication Number: US-2023145041-A1

Title: Apparatus and method for gene amplification

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority from Korean Patent Application No. 10-2021-0151948, filed on Nov. 8, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Apparatuses and methods consistent with example embodiments relate to amplifying a gene extracted from a biological sample to identify genetic mutations and various infections. 
     2. Description of the Related Art 
     Clinical or environmental samples are analyzed by a series of biochemical, chemical, and mechanical treatment processes. Recently, there has been considerably increasing interest in developing techniques for diagnosis or monitoring of biological samples. Molecular diagnosis based on nucleic acid amplification techniques has excellent accuracy and sensitivity, and thus is increasingly used in various applications, ranging from diagnosis of infectious diseases or cancer to pharmacogenomics, development of new drugs, and the like. Microfluidic devices are widely used to analyze samples in a simple and accurate manner according to various purposes. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided an apparatus for gene amplification, the apparatus including: an upper main body comprising a first inlet to receive a sealing solution, a second inlet to receive a sample solution, and an upper passage that allows the sample solution and the sealing solution to move by capillary action; a lower main body disposed to oppose the upper main body, and having a lower passage through which the sealing solution moves by capillary action after being injected from the first inlet of the upper main body; a gene amplification chip configured to be inserted between the upper main body and the lower main body; and a porous medium configured to be inserted between the upper main body and the lower main body. 
     The upper passage may include a first injection path for guiding the sample solution and the sealing solution toward the gene amplification chip, a first main flow path disposed on an upper portion of the gene amplification chip, and a first discharge path for guiding the sample solution and the sealing solution toward the porous medium. The lower passage may include a second injection path for guiding the sealing solution toward the gene amplification chip, a second main flow path disposed on a lower portion of the gene amplification chip, and a second discharge path for guiding the sealing solution toward the porous medium. 
     The first main flow path may be inclined from the first injection path toward the first discharge path, or the second main flow path may be inclined from the second injection path toward the second discharge path. 
     At least one of the first main flow path and the second main flow path may have an inclination angle of 0° to 35°. 
     At least one of the first injection path, the first discharge path, the second injection path, and the second discharge path may have a width which is not constant in a flow direction of the sample solution or the sealing solution. 
     A width of the first injection path and a width of the second injection path may linearly decrease in the flow direction of the sample solution or the sealing solution. 
     A width of the first discharge path and a width of the second discharge path may linearly increase in the flow direction of the sample solution or the sealing solution. 
     A width of the first injection path, a width of the second injection path, a width of the first discharge path, and a width of the second discharge path may be in a range of 1 μm to 5 mm. A width of the first main flow path and a width of the second main flow path may be in a range of 1 μm to 10 cm. 
     The upper main body may further include an auxiliary channel which is provided on both sides of the upper passage, and which allows the sealing solution to move by capillary action through the auxiliary channel. 
     The auxiliary channel may be stepped with respect to the upper passage. 
     The upper passage and the lower passage may include a hydrophilic material having a contact angle of 90° or less with respect to water. 
     The sealing solution may be a non-polar solution that is not mixed with the sample solution. 
     The porous medium may include a hydrophilic material, and may have a plurality of pores or a plurality of pin type microstructures. 
     A diameter of each of the plurality of pores or each of the plurality of pin type microstructures may be in a range of 0.001 μm to 100 μm, and may be smaller than a width of the upper passage and a width of the lower passage. A distance between the plurality of pores or a distance between the plurality of pin type microstructures may be in a range of 0.001 μm to 100 μm. 
     A diameter of the first inlet may be greater than a diameter of the second inlet. 
     The diameter of the first inlet may be greater than or equal to a width of an injection path of the upper passage; and the diameter of the second inlet may be in a range of 0.1 μm to 4500 μm. 
     The upper main body may further include an air pressure maintenance hole disposed on an upper portion of the porous medium. 
     The gene amplification chip may include a substrate, and an array of through holes which pass through the substrate in a direction from an upper surface to a lower surface of the substrate, and in which a gene amplification reaction occurs. 
     The gene amplification chip may include a photothermal film disposed on at least one of the upper surface and the lower surface of the substrate, and a partition wall of the respective through holes, and generating heat by using received light. 
     According to another aspect of the present disclosure, there is provided an apparatus for detecting a microfluid, the apparatus including: a gene amplifier; an optical unit including a light emitter and a light detector to emit light onto a sample solution and to measure an optical signal scattered or reflected from the sample solution, while a gene amplification reaction is performed in a gene amplification chip of the gene amplifier, or after the gene amplification reaction is complete; and a processor configured to detect an amplified gene by analyzing the optical signal, wherein the gene amplifier may include: an upper main body comprising a first inlet to receive a sealing solution, a second inlet to receive the sample solution, and an upper passage that allows the sample solution and the sealing solution to move by capillary action; a lower main body disposed to oppose the upper main body, and having a lower passage through which the sealing solution moves by capillary action after being injected from the first inlet of the upper main body; the gene amplification chip configured to be inserted between the upper main body and the lower main body; and a porous medium configured to be inserted between the upper main body and the lower main body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects will be more apparent by describing certain example embodiments, with reference to the accompanying drawings, in which: 
         FIG.  1    is a block diagram illustrating an apparatus for gene amplification according to an embodiment of the present disclosure; 
         FIG.  2 A  is a front view of an apparatus for gene amplification according to an embodiment of the present disclosure; 
         FIG.  2 B  is a plan view of an apparatus for gene amplification according to an embodiment of the present disclosure; 
         FIG.  3 A  is a plan view of an apparatus for gene amplification according to another embodiment of the present disclosure; 
         FIGS.  3 B and  3 C  are diagrams illustrating a structure and an effect of an auxiliary channel; 
         FIG.  4 A  is a diagram illustrating a gene amplification chip according to an embodiment of the present disclosure; 
         FIG.  4 B  is a diagram illustrating a side surface of a gene amplification chip, on which a photothermal film is deposited; 
         FIGS.  5  to  8    are block diagrams illustrating an apparatus for detecting a microfluid according to embodiments of the present disclosure; and 
         FIG.  9    is a flowchart illustrating a method of gene amplification according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments are described in greater detail below with reference to the accompanying drawings. 
     In the following description, like drawing reference numerals are used for like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the example embodiments. However, it is apparent that the example embodiments can be practiced without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the description with unnecessary detail. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Any references to singular may include plural unless expressly stated otherwise. In addition, unless explicitly described to the contrary, an expression such as “comprising” or “including” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Also, the terms, such as ‘unit’ or ‘module’, etc., should be understood as a unit that performs at least one function or operation and that may be embodied as hardware, software, or a combination thereof. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or any variations of the aforementioned examples. 
       FIG.  1    is a block diagram illustrating an apparatus  100  for gene amplification according to an embodiment of the present disclosure. Referring to  FIG.  1   , the apparatus  100  for gene amplification includes an upper main body  110 , a lower main body  120 , a gene amplification chip  130 , and a porous medium  140 . The apparatus  100  may be also referred to as a gene amplifier. 
     The upper main body  110  includes a first inlet  111 , a second inlet  112 , an upper passage  113 , a gene amplification chip fixing column  114 , and an air pressure maintenance hole  115 . 
     The first inlet  111  may be an inlet into which a sealing solution is injected, and the second inlet  112  may be an inlet into which a sample solution is injected. 
     The sealing solution may be a non-polar solution that is not mixed with the sample solution. In particular, the sealing solution may be oil, but is not limited thereto. When a gene amplification reaction occurs with the sample solution being loaded into the gene amplification chip  130 , if an upper surface and a lower surface of the gene amplification chip  130  are in contact with a gas, the sample solution may be evaporated and lost rapidly during the gene amplification reaction. In this case, the sealing solution may be coated on the upper surface, the lower surface, and the like of the gene amplification chip  130 , thereby preventing loss of the loaded sample solution. 
     The sample solution may be bio-fluids, including at least one of respiratory secretions, blood, urine, perspiration, tears, saliva, etc., or a swab sample of the upper respiratory tract, or a solution of the bio-fluid or the swab sample dispersed in other medium. In this case, the other medium may include water, saline solution, alcohol, phosphate buffered saline solution, vital transport media, etc., but is not limited thereto. A volume of the sample may be in a range of 1 μL to 1000 μL, but is not limited thereto. 
     The sample solution may contain microbes. The microbes may include a duplex of one or more of ribonucleic acid (RNA) virus, deoxyribonucleic acid (DNA) virus, peptide nucleic acid (PNA) virus, and locked nucleic acid (LNA) virus, bacteria, pathogen, germ, virus, oligopeptide, protein, toxin, etc., but the microbes are not limited thereto. 
     The microbes may contain genes. For example, the genes may include a duplex of one or more of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), peptide nucleic acid (PNA), and locked nucleic acid (LNA), but the genes are not limited thereto. 
     While  FIG.  1    illustrates the first inlet  111  and the second inlet  112  as having a circular shape, but the shape is not limited thereto, and the first inlet  111  and the second inlet  112  may have a polygonal shape, such as square, pentagon, and the like. 
     The gene amplification chip fixing column  114  is disposed on an upper portion of the gene amplification chip  130 , to fix the gene amplification chip  130  so that the gene amplification chip  130 , inserted between the upper main body  110  and the lower main body  120 , may not be separated to the outside. 
     The air pressure maintenance hole  115  may be disposed on an upper portion of the porous medium  140 . The air pressure maintenance hole  115  may serve to maintain gas pressure in the upper passage  113 , the lower passage  122 , and the porous medium  140  at atmospheric pressure. In this case, a diameter of the air pressure maintenance hole  115  may be in a range of 10 μm to 5 mm, but is not limited thereto. 
     Although not illustrated in  FIG.  1    for convenience of explanation, the upper main body  110  may further include an insertion groove of the gene amplification chip and an insertion groove of the porous medium. The respective insertion grooves may be formed at positions corresponding to an insertion groove  123  of the gene amplification chip and an insertion groove  124  of the porous medium in the lower main body  120 . 
     The lower main body  120  may include a first inlet connector  121 , a lower passage  122 , the insertion groove  123  of the gene amplification chip and the insertion groove  124  of the porous medium. 
     The first inlet connector  121  may be formed at a position corresponding to the first inlet  111  of the upper main body  110 , as illustrated in  FIG.  1   . The sealing solution injected from the first inlet  111  of the upper main body  110  may be injected into the lower main body  120  through the first inlet connector  121  of the lower main body  120 . 
     The gene amplification chip  130  may be inserted between the insertion groove  123  of the gene amplification chip in the lower main body  120  and the insertion groove of the gene amplification chip in the upper main body  110 . The porous medium  140  may be inserted between the insertion groove  124  of the porous medium in the lower main body  120  and the insertion groove of the porous medium in the upper main body  110 . 
     Although not illustrated in  FIG.  1    for convenience of explanation, the lower main body  120  may further include a gene amplification chip fixing column, in which case the gene amplification chip fixing column of the lower main body  120  may be disposed at a position corresponding to the gene amplification chip fixing column  114  of the upper main body  110 . 
     The upper passage  113  and the lower passage  122  may be made of an inorganic matter, such as silicon (Si), glass, polymer, metal, ceramic, graphite, etc., acrylic material, polyethylene terephthalate (PET), polycarbonate, polystylene, and polypropylene, but is not limited thereto. 
     The sample solution may be loaded into the gene amplification chip  130  through the upper passage  112 , and the sample solution and the sealing solution may move toward the porous medium  140  through the upper passage  113  and/or the lower passage  122 . In this case, the injected sample solution and sealing solution may move by capillary action. 
     For example, the injected sample solution may be loaded into the gene amplification chip  130  by capillary action through the upper passage  112 , in which case the sample solution, not loaded into the gene amplification chip  130 , may move by capillary action toward the porous medium  140  through the upper passage  113 . The sealing solution injected thereafter may move by capillary action toward the gene amplification chip  130  and the porous medium  140  through the upper passage  113  and the lower passage  122 . In this case, the sealing solution may be filled in all of the upper passage  113 , the lower passage  112 , the upper surface and lower surface of the gene amplification chip  130 , and the porous medium  140 , thereby preventing the sample solution, loaded into the gene amplification chip  130 , from being in contact with a gas. 
     A material or a structure for pre-treatment of the sample solution may be provided inside or outside of the upper passage  113 , in which case the sample solution may be pre-treated before being loaded into the gene amplification chip  130  through the upper passage  113 . For example, a pre-treatment process, such as heating, chemical treatment, treatment with magnetic beads, solid phase extraction, treatment with ultrasonic waves, etc., may be performed. The upper passage  113  may include a filter for passing only a fluid while blocking fine particles in the pre-treated sample. The filter may be formed in the shape of a single layer or multilayer film having microholes, and may block fine particles of a desired size according to the size of the holes. The filter may be made of, for example, silicon, polyvinylidene fluoride (PVDF), polyethersulfone, polycarbonate, glass fiber, Polypropylene, Cellulose, Mixed cellulose esters, Polytetrafluoroethylene (PTFE), Polyethylene Terephthalate, Polyvinyl chloride (PVC), Nylon, Phosphocellulose, Diethylaminoethyl cellulose (DEAE), and the like, but is not limited thereto. The holes may have various shapes, e.g., a circular shape, a rectangular shape, a slit shape, an irregular shape due to glass fiber, and the like. 
     In addition, the upper passage  113  may include a field effect transistor (FET), a silicon (Si) photonic structure, a  2 D micro/nano material/structure, and the like. Further, the upper passage  113  may include a structure having optical or electrical heating properties for controlling temperature of the sample. 
     The upper passage  113  may contain reactants for each gene to be amplified. In this case, the gene to be amplified may be, for example, a duplex of one or more of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), peptide nucleic acid (PNA), and locked nucleic acid (LNA), oligopeptide, protein, toxin, and the like. The reactants for each gene may include, for example, reverse transcriptase, polymerase, ligase, peroxidase, primer, probe, etc., but is not limited thereto. The primer may include oligonucleotide, for example, target specific single strand oligonucleotide. Further, the probe may include oligonucleotide, for example, target specific single strand oligonucleotide, a fluorescent material, quencher, and the like. The probe may exhibit a characteristic fluorescence signal by interacting with a specific target material in a solution, in which different types of materials are dissolved. Such characteristic signal may be tracked, detected, and processed for a predetermined period of time by an optical unit and/or a processor of the apparatus for gene amplification, for use in detecting the amplified gene. 
     The upper passage  113  and/or the lower passage  122  may be made of a material and a structure for facilitating capillary action. 
     For example, the upper passage  113  and/or the lower passage  122  may be made of a hydrophilic material having a contact angle of 90° or less with respect to water. For example, the upper passage  113  and/or the lower passage  122  may be made of a material having a contact angle of 10° or less with respect to water, but the material is not limited thereto. 
     In another example, the upper passage  113  and/or the lower passage  122  may not have a constant width and/or height. In another example, the upper passage  113  may further include an auxiliary channel for facilitating capillary action. Hereinafter, a structure of the apparatus  100  for gene amplification for facilitating capillary action will be described in detail with reference to  FIGS.  2 A to  3 C . 
       FIG.  2 A  is a front view of an apparatus for gene amplification according to an embodiment of the present disclosure. In  FIG.  2 A , the first inlet  111 , the second inlet  112 , upper passages  113   a ,  113   b , and  113   c , the first inlet connector  121 , lower passages  122   a ,  122   b , and  122   c , the gene amplification chip  130 , the porous medium  140 , and the air pressure maintenance hole  115  are illustrated. 
     The upper passage may include an injection path  113   a  for guiding the injected sample solution and sealing solution toward the gene amplification chip  130 , a main flow path  113   b  disposed on an upper portion of the gene amplification chip  130 , and a discharge path  113   c  for guiding the sample solution, having passed through the main flow path  113   b , and the sealing solution toward the porous medium  140 . 
     The lower passage may include an injection path  122   a  for guiding the injected sealing solution toward the gene amplification chip  130 , a main flow path  122   b  disposed on a lower portion of the gene amplification chip  130 , and a discharge path  122   c  for guiding the sealing solution, having passed through the main flow path  122   b , toward the porous medium  140 . 
     A height h i  of the injection path  113   a  of the upper passage and a height of the injection path  122   a  of the lower passage may be in a range of 1 μm to 10 mm, but the heights are not limited thereto. 
     A height h o  of the discharge path  113   c  of the upper passage and a height h o,u  of the discharge path  122   c  of the lower passage may be in a range of 1 μm to 10 mm, but the heights are not limited thereto. In this case, the height h o  of the discharge path  113   c  of the upper passage and the height h o,u  of the discharge path  122   c  of the lower passage may be expressed by h i −L tan α and h i,u −L tan α u , respectively. In this case, L denotes the length of the main flow paths  113   b  and  122   b , and α and α u  denote an inclination angle of the main flow path  113   b  of the upper passage and an inclination of the main flow path  122   b  of the lower flow path, which will be described below. 
     The height of the main flow path  113   b  of the upper passage and/or the height of the main flow path  122   b  of the lower passage may not be constant. For example, the main flow path  113   b  of the upper passage and/or the main flow path  122   b  of the lower passage may be inclined from the injection paths  113   a  and  122   a  toward the discharge paths  113   c  and  122   c  as illustrated in  FIG.  2 A , but are not limited thereto. 
     In this case, the main flow path  113   b  of the upper passage may have an inclination angle α, and the main flow path  122   b  of the lower passage may have an inclination angle α u . In this case, the inclination angles α and α u  may be in a range of 0° to 35°, but are not limited thereto. Further, while  FIG.  2 A  illustrates that the inclination angles α and α u  are constant, but are not limited thereto, and the heights of the main flow path  113   b  of the upper passage and/or the main flow path  122   b  of the lower passage may decrease linearly. In this case, the inclination angles α and α u  may be different from each other. 
     As described above, the main flow path  113   b  of the upper passage and/or the main flow path  122   b  of the lower passage are inclined from the injection paths  113   a  and  122   a  toward the discharge paths  113   c  and  122   c , such that due to a height difference in the injection paths and the discharge paths, the sample solution and/or the sealing solution in the main flow paths  113   b  and  122   b  may be moved smoothly. Further, as the main flow paths  113   b  and  122   b  are inclined, capillary action may easily occur in terms of Laplace pressure in a flow direction of the sample solution and/or the sealing solution, which will be described later. 
       FIG.  2 B  is a plan view of an apparatus for gene amplification according to an embodiment of the present disclosure. In  FIG.  2 B , the first inlet  111 , the second inlet  112 , an injection path  113   a  of the upper passage, a main flow path  113   b  of the upper passage, a discharge path  113   c  of the upper passage, and the porous medium  140  are illustrated. 
     Widths of the injection path  113   a  and/or the discharge path  113   c  may not be constant in a flow direction of the sample solution or the sealing solution, i.e., in a direction from the first inlet  111  to the porous medium  140 . 
     Referring to  FIG.  2 B , the injection path  113   a  may have a width which decreases in a flow direction of the sample solution or the sealing solution, and the discharge path  113   c  may have a width which increases in a flow direction of the sample solution or the sealing solution. While  FIG.  2 B  illustrates an example in which the widths of the injection path  113   a  and the discharge path  113   c  may decrease or increase linearly, but the widths are not limited thereto. 
     Further,  FIG.  2 B  is a plan view in which the lower passage is not illustrated, but the injection path and the discharge path of the lower passage may have the same shapes as those of the injection path  113   a  and the discharge path  113   c  of the upper passage. However, the present disclosure is not limited thereto, and any one of the injection path  113   a  of the upper passage, the discharge path  113   c  of the upper passage, the injection path of the lower passage, and the discharge path of the lower passage, or only some thereof may have widths which are not constant in a direction toward the porous medium  140 . 
     As the width of the injection path  113   a  decreases in the flow direction as illustrated in  FIG.  2 B , Laplace pressure in the flow direction may increase, such that a flow speed may increase by capillary action. 
       FIG.  3 A  is a plan view of an apparatus for gene amplification according to another embodiment of the present disclosure. Referring to  FIG.  3 A , the first inlet  111 , the second inlet  112 , the upper passage  113 , the air pressure maintenance hole  115 , and the auxiliary channel  116  may be included in the upper main body of the apparatus for gene amplification. 
     Herein, d 1  denotes a diameter of the first inlet, d 2  denotes a diameter of the second inlet, w i  denotes a width of the injection path of the upper passage, w m  denotes a width of the main flow path of the upper passage, w o  denotes a width of the discharge path of the upper passage, and L denotes a length of the main flow path of the upper passage. 
     The diameter d 1  of the first inlet  111  may be greater than the diameter d 2  of the second inlet  112 . In this case, the diameter d 1  of the first inlet  111  may be greater than or equal to the width w i  of the injection path of the upper passage  113 , and may be less than or equal to a value obtained by adding twice the width of the auxiliary channel to the width w i  of the injection path of the upper passage  113 . The diameter d 2  of the second inlet  112  may be in a range of 0.1 μm to 4500 μm. However, the diameters d 1  and d 2  of the first inlet  111  and the second inlet  112  are not limited thereto. 
     The width w i  of the injection path of the upper passage and the width w o  of the discharge path of the upper passage may be in a range of 1 μm to 5 mm, but are not limited thereto. The width w m  of the main flow path of the upper passage may be in a range of 1 μm to 10 cm, but is not limited thereto. In addition, the width w m  of the main flow path of the upper passage may increase from the injection path toward the discharge path, and then may decrease again, but is not limited thereto. The length L of the main flow path of the upper passage may be in a range of 1 μm to 10 cm, but is not limited thereto, and may vary depending on the shape of the gene amplification chip  130 . 
     The auxiliary channel  116  may be formed on both sides of the upper passage  113 . The sealing solution injected from the first inlet may move by capillary action not only through the upper passage  113  and the lower passage  122 , but also through the auxiliary channel  116  formed on both sides of the upper passage  113 , which will be described in detail with reference to  FIGS.  3 B and  3 C .  FIGS.  3 B and  3 C  are diagrams illustrating a structure and an effect of the auxiliary channel. 
       FIG.  3 B  illustrates one cross-section K of  FIG.  3 A .  FIG.  3 B  illustrates the gene amplification chip  130 , the upper passage  130 , and the auxiliary channel  116  formed on both sides of the upper passage  130 , in which w i  and h i  respectively denote the width and height of the injection path of the upper passage, and a and Δh denote the width and height of the auxiliary channel, respectively. 
     As illustrated in  FIG.  3 B , the auxiliary channel  116  may be stepped with respect to the upper passage  113 , i.e., may have a height difference from the upper passage  113 , but is not limited thereto. For example, unlike  FIG.  3 B , the height h i  of the upper passage  113  may be equal to the height Δh of the auxiliary channel  116 , or the height h i  of the upper passage  113  may be greater than the height Δh of the auxiliary channel  116 . In this case, the width a and height Δh of the auxiliary channel  116  may be in a range of 1 μm to 5 mm, but are not limited thereto. 
       FIG.  3 C  is a diagram explaining an effect of the auxiliary channel. 
     In  FIG.  3 C , ( 1 ) and ( 2 ) are diagrams illustrating structures in which no auxiliary channel is formed, and ( 3 ) and ( 4 ) are diagrams illustrating structures in which an auxiliary channel is formed. 
     When all surfaces of the passage are hydrophilic, a very high Laplace pressure is generated due to a small radius of curvature of a liquid at corners thereof, such that a very fast flow is formed along the corners (Corner flow). Referring to ( 1 ) and ( 2 ) of  FIG.  3 C , it can be seen that a faster flow is formed along the corners of the passage. As a result, a uniform flow may not be formed in the passage, thereby generating bubbles. 
     This phenomenon may be resolved by providing the auxiliary channel on some of the surfaces of the passage, as illustrated in ( 3 ) and ( 4 ) of  FIG.  3 C . When the auxiliary channel is provided on both sides of the passage, a flow may not be formed in the corresponding direction as a driving pressure becomes zero, such that it is possible to prevent a fast flow at the corners. 
     That is, the auxiliary channel may serve to allow the sample solution, having a limited volume, to continuously move by capillary action toward the porous medium through the upper passage without external power. 
     The lower main body of the apparatus for gene amplification may not include the auxiliary channel. 
     Referring back to  FIG.  1   , the sample solution may flow through the upper passage  113  to be loaded into the gene amplification chip  130 , in which case the gene contained in the sample solution may be amplified. 
     The gene amplification chip  130  may be inserted between the upper main body  110  and the lower main body  120 . For example, the gene amplification chip  130  may be inserted into an insertion groove (e.g., insertion groove  123 ) of the gene amplification chip, which may be included in the upper main body  110  and the lower main body  120 . A shape of the gene amplification chip  130  and the photothermal film disposed on the gene amplification chip  130  will be described below with reference to  FIGS.  4 A and  4     b.    
       FIG.  4 A  is a diagram illustrating a gene amplification chip according to an embodiment of the present disclosure. 
     Referring to  FIG.  4 A , the gene amplification chip  130  includes a substrate  131 , a substrate upper surface  132 , a substrate lower surface  133 , and an array of through holes  134 . 
     The substrate  131  may be made of any one of inorganic matter, such as silicon (Si), glass, polymer, metal, ceramic, graphite, etc., and acrylic material, polyethylene terephthalate (PET), polycarbonate, polystylene, and polypropylene, but is not limited thereto. 
     In this case, the substrate  131  may be made of a hydrophilic material having a contact angle of 90° or less with respect to water, but is not limited thereto. 
     A thickness of the substrate, i.e., a length from the upper surface  132  to the lower surface  133  of the substrate  131 , may be 1 mm or less, but is not limited thereto, and may be changed to various numbers. 
     As illustrated herein, the through holes  134  may pass through the substrate  131  in a direction from the upper surface  132  to the lower surface  133 . When the through holes  134  are formed, an etching process such as Deep Reactive Ion Etching (DRIE) or a thinning process including CMP treatment may be performed. A volume of the through holes  134  may be 1 nL or less, and the number of the through holes  134  may be at least 20,000 or more. The through holes  134  may have a cylindrical or hexagonal prism shape, but its shape is not limited thereto, and may be formed in various shapes such as other polygonal prism and the like. In the case where the through holes  134  have the hexagonal prism shape, a diagonal distance of a cross-section of the through holes  134  may be 100 μm or less. However, the number, shape, and volume of the through holes  134  are not limited thereto, and may be changed variously. 
     A gene amplification reaction occurs in the through holes  134 . In this case, reverse transcription of an RNA sample is performed in the respective through holes  134  by using a reverse transcriptase. The gene amplification reaction may include, for example, a nucleic acid amplification reaction including at least one of polymerase chain reaction (PCR) amplification and isothermal amplification, a redox reaction, a hydrolytic reaction, and the like. In this case, the gene may include a duplex of one or more of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), peptide nucleic acid (PNA), and locked nucleic acid (LNA), but is not limited thereto. While the gene amplification reaction is performed in the through holes  134 , an optical signal is measured by the optical unit and/or the processor of the apparatus for gene amplification, and the amplified gene may be detected based on the measured optical signal. In this case, the optical signal may include fluorescence, phosphor, absorbance, surface plasmon resonance, and the like. As described above, the gene amplification chip  130  may be used to detect, for example, the presence of a target DNA template, quantitative information, and the like. 
     A structure for removing gas bubbles, e.g., a bubble trap or a bubble removing member/chamber, and/or a gas permeable material, etc., may be disposed in the respective through holes  134  or at the inlet of the array of the through holes  134 . 
     The gene amplification chip  130  may include an optical heating element, such as a photothermal film, which reacts to an external light source. However, the gene amplification chip  130  is not limited thereto, and may also include an electrical heating element, such as a Peltier element and the like, to have electrothermal properties, instead of the optical heating element. For convenience of explanation, a shape of the gene amplification chip  130 , on which the photothermal film as an example of the optical heating element is deposited, will be described below with reference to  FIG.  4 B . 
       FIG.  4 B  is a diagram illustrating a side surface of the gene amplification chip  130 , on which a photothermal film is deposited. 
     Referring to  FIG.  4 B , the gene amplification chip  130  may further include a photothermal film  135  in addition to the substrate  131 , the substrate upper surface  132 , the substrate lower surface  133 , and the array of the through holes  134  which are described above.  FIG.  4 B  illustrates a state in which the photothermal film  135  is deposited on the substrate upper surface  132 , the substrate lower surface, and a partition wall of the through holes  134 . In this case, the photothermal film may be deposited in a pattern. 
     Unlike the example of  FIG.  4 B , however, the photothermal film  135  may be deposited on only any one of the substrate upper surface  132 , the substrate lower surface  133 , and the partition wall of the through holes  134 , or may be deposited on only the substrate upper surface  132  and the substrate lower surface  133 , which is more desirable in terms of process complexity or production costs than the case where the photothermal film  135  is deposited on all of the substrate upper surface  132 , the substrate lower surface, and the partition wall of the through holes  134 . 
     A thickness of the photothermal film  135  may be 10 μm or less, but is not limited thereto. Further, the photothermal film  135  may be formed as a metal layer, but is not limited thereto and may be made of a metal oxide material, metalloid, and base metal. For example, the photothermal film  135  may be formed of a tungsten-based material having excellent infrared absorptivity, and thus achieving a photothermal conversion effect during laser emission. The photothermal film  135  may have a nanostructure. For example, the photothermal film  135  may be formed as nanoparticles, nanorod, nanodisc, or nanoisland, which has a size of 50 nm or less in diameter and 50 nm or less in thickness, but is not limited thereto, and may be formed in various nanostructures. 
     Further, although not illustrated in  FIG.  4 B , the photothermal film  135  may further contain carbon black, visible light dye, ultraviolet dye, infrared dye, fluorescent dye, radiation-polarizing dye, pigment, metallic compound, and another suitable absorber material as a photothermal conversion material. 
     The photothermal film  135  may receive light from a light source, and may generate heat by photonic heating using the received light. In this case, as the photothermal film  135  is disposed at a plurality of positions of the gene amplification chip  130 , temperature may be controlled at a uniform level, and heat generation efficiency may be improved. 
     In addition to the photothermal film  135 , the gene amplification chip  130  may further include: an adhesive layer disposed between the substrate  131  and the photothermal film  135  and improving adhesive strength of the photothermal film  135 ; a separate element for improving adhesive strength between the photothermal film  135  and the substrate  131 ; an auxiliary film disposed to surround the photothermal film  135  and preventing hindrance to the gene amplification process within the through holes; and other material for amplifying the photothermal effect of the photothermal film  135 . 
     Referring back to  FIG.  1   , the porous medium  140  may be inserted between the upper main body  110  and the lower main body  120 . For example, the porous medium  140  may be inserted into an insertion groove (e.g., insertion groove  124 ) of the porous medium, which may be included in the upper main body  110  and the lower main body  120 , as described above. 
     The porous medium  140  may be made of a hydrophilic material. For example, the porous medium  140  may be formed of cotton, filter paper, hydrogel, sponge, and the like 
     The porous medium  140  may include a plurality of pores or a plurality of pin type microstructures. In this case, a diameter of the pores or the pin type microstructures is smaller than the widths of the upper passage and the lower passage, and may be in a range of 0.001 μm to 100 μm, but is not limited thereto. A distance between the plurality of pores or a distance between the plurality of the pin type microstructures may be in a range of 0.001 μm to 100 μm, but is not limited thereto. 
     The porous medium  140 , which has a wide surface area for its volume with high absorbing properties, may pull the sample solution with a greater force than the upper passage  113 , thereby absorbing the sample solution rapidly. In this case, the porous medium  140  may absorb a large amount of sample solution and sealing solution with a limited length, thereby allowing the apparatus  100  for gene amplification to be manufactured in a smaller size. 
       FIGS.  5  to  8    are block diagrams illustrating an apparatus for detecting a microfluid according to embodiments of the present disclosure. 
     Referring to  FIG.  5   , an apparatus  500  for detecting a microfluidic includes an apparatus  510  for gene amplification, an optical unit  520 , and a processor  530 . The apparatus  510  for gene amplification is described in detail above with reference to  FIGS.  1  to  4 B , such that the following description will be focused on the optical unit  520  and the processor  530 . 
     The optical unit  520  may measure an optical signal while the gene amplification reaction is performed in the respective through holes of an array of micro/nano through holes. In this case, the optical signal may include fluorescence, phosphor, absorbance, surface plasmon resonance, and the like. The optical unit  520  may include a light source for emitting light onto the sample solution in the micro/nano through holes, and a detector (e.g., a light detector such as a photodiode) for detecting the optical signal reflected from the sample solution in the micro/nano through holes. The light source may include LED, laser, vertical-cavity surface-emitting laser (VCSEL), etc., but is not limited thereto. Further, the detector may include a photomultiplier tube, a photo detector, a photomultiplier tube array, a photo detector array, a complementary metal-oxide semiconductor (CMOS) image sensor, etc., but is not limited thereto. In addition, the optical unit  520  may further include a filter for passing light of a specific wavelength, a mirror for directing the light radiating from the micro/nano through holes toward the detector, a lens for collecting light radiating from the micro/nano through holes, and the like. 
     The processor  530  may be electrically connected to the optical unit  520 , and may control driving of the light source of the optical unit  520 . Further, the processor  530  may receive the optical signal from the detector and analyze the optical signal, and may detect biomolecules based on the analysis. For example, the processor  530  may perform quantitative analysis of the amplified gene based on a result of digital nucleic acid amplification, detected by the detector, and Poisson distribution. 
     Referring to  FIG.  6   , an apparatus  600  for detecting a microfluid according to an embodiment of the present disclosure may further include a pre-treatment unit  610  in addition to the configuration of the apparatus  500  for detecting a microfluid of  FIG.  5   . 
     The pre-treatment unit  610  may perform a pre-treatment process, such as heating the sample solution present in the main flow path of the upper passage, chemical treatment, treatment with magnetic beads, solid phase extraction, treatment with ultrasonic waves, and the like. To this end, the pre-treatment unit  610  may include various materials or structures for pre-treatment, such as magnetic beads, an ultrasonic device, an optical/electric heating device, etc., which are provided inside and/or outside of the main flow path of the upper passage, and the pre-treatment unit  610  may control these materials or structures. At least some of the functions of the pre-treatment unit  610  may be integrated into the processor  530 . 
     Referring to  FIG.  7   , an apparatus  700  for detecting a microfluid according to an embodiment of the present disclosure may further include a temperature controller (e.g., a thermostat, a heating system, and/or a cooling system)  710  in addition to the apparatus  500  or  600  for detecting a microfluid according to the embodiment of  FIG.  5    or  FIG.  6   . 
     The temperature controller  710  may control temperature of the sample solution present in in the upper passage and/or the respective through holes of the gene amplification chip. 
     For example, the temperature controller  710  may control temperature of the sample solution present in the injection path of the upper passage to be maintained at an isothermal temperature of 95° C. or higher, or to be maintained at an isothermal temperature within a range of 30° C. to 60° C. 
     In another example, the temperature controller  710  may control temperature of the sample solution loaded into the gene amplification chip to be, for example, a thermal dissolution temperature, a reverse transcription temperature and a gene amplification temperature. 
     In this case, the temperature controller  710  may include an electric heater and/or an optical heater, and may control the temperature of the sample solution by using the electric heater and/or optical heater. 
     The electric heater may include, for example, a heating element and/or a Peltier element. The optical heater may include, for example, one or more light sources disposed outside of the apparatus  510  for gene amplification and emitting light onto the gene amplification chip included in the apparatus  510  for gene amplification, and the like. 
     Further, the temperature controller  710  may include a temperature sensor disposed inside or outside of the apparatus  510  for gene amplification and measuring the temperature of the sample solution present in the upper passage and the gene amplification chip. In this case, the temperature sensor may include a thermocouple having a bimetal junction generating temperature-dependent electric and magnetic fields (EMFs), a resistive thermometer including materials having electrical resistance proportional to temperature, thermistors, an integrated circuit (IC) temperature sensor, a quartz thermometer, etc., but is not limited thereto. 
     Referring to  FIG.  8   , an apparatus  800  for detecting a microfluid according to an embodiment of the present disclosure may further include a storage  810 , an output interface  820 , and a communication interface  830  in addition to the configuration of the apparatus  500 ,  600 , and  700  for detecting a microfluid according to the embodiment of  FIG.  7   ,  FIG.  8   , or  FIG.  9   . 
     The storage  810  may store, for example, a variety of reference information for gene amplification and/or a gene amplification result, and the like. The storage  810  may include at least one storage medium of a flash memory type memory, a hard disk type memory, a multimedia card micro type memory, a card type memory (e.g., an SD memory, an XD memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a Programmable Read Only Memory (PROM), a magnetic memory, a magnetic disk, and an optical disk, and the like, but is not limited thereto. 
     The output interface  820  may output, for example, a gene amplification process, a gene amplification result and/or interaction information with a user during the gene amplification process, and the like. The output interface  820  may provide a user with information by visual, audio, and tactile methods and the like using a visual output module (e.g. display), an audio output module (e.g., speaker), a haptic module, and the like. 
     The communication interface  830  may communicate with an external device. For example, the communication interface  830  may transmit data generated by the apparatus  800  for detecting a microfluid, e.g., a gene amplification result, and the like to an external device, and may receive data required for gene amplification and/or for analysis of the gene amplification result from the external device. In this case, the external device may be medical equipment, a printer to print out results, or a display device. In addition, the external device may be a digital TV, a desktop computer, a mobile phone, a smartphone, a tablet PC, a laptop computer, Personal Digital Assistants (PDA), Portable Multimedia Player (PMP), a navigation device, an MP3 player, a digital camera, a wearable device, etc., but is not limited thereto. 
     The communication interface  830  may communicate with the external device by using Bluetooth communication, Bluetooth Low Energy (BLE) communication, Near Field Communication (NFC), WLAN communication, Zigbee communication, Infrared Data Association (IrDA) communication, Wi-Fi Direct (WFD) communication, Ultra-Wideband (UWB) communication, Ant+ communication, WIFI communication, Radio Frequency Identification (RFID) communication, 3G, 4G, and 5G communications, and the like. However, this is merely exemplary and is not intended to be limiting. 
       FIG.  9    is a flowchart illustrating a method of gene amplification according to an embodiment of the present disclosure. 
     The method of gene amplification of  FIG.  9    may be performed by the apparatuses  500 ,  600 ,  700 , and  800  for detecting a microfluid according to the embodiments of  FIGS.  5  to  8   , which are described in detail above, and thus will be briefly described below in order to avoid redundancy. 
     First, the apparatus for detecting a microfluid may inject a sample solution into an inlet for injecting the sample solution in operation  910 . 
     Then, the injected sample solution may be loaded into the gene amplification chip by capillary action in operation  920 . 
     The injected sample solution may move by capillary action through the upper passage. In this case, the upper passage may have a material and structure for facilitating capillary action. For example, the upper passage may be made of a material having a contact angle of 10° or less with respect to water. In another example, the main flow path of the upper passage may be inclined from the injection path toward the discharge path, and/or widths of the injection path and the discharge path may not be constant in a flow direction of the sample solution. A detailed description thereof will be omitted. 
     Then, the sample solution not loaded into the gene amplification chip may move by capillary action toward the porous medium included in the apparatus for gene amplification in operation  930 . 
     In this case, capillary action may easily occur with a material and structure for facilitating capillary action, and/or high hydrophilic properties of the porous medium. A detailed description thereof will be omitted. 
     Subsequently, the apparatus for detecting a microfluid may inject a sealing solution into an inlet for injecting the sealing solution in operation  940 . 
     In this case, a diameter of the inlet, into which the sealing solution is injected, may be greater than a diameter of the inlet into which the sample solution is injected. The sealing solution may be a non-polar solution that is not mixed with the sample solution. When a gene amplification reaction occurs with the sample solution being loaded into the gene amplification chip, if an upper surface and a lower surface of the gene amplification chip are in contact with a gas, the sample solution may be evaporated and lost rapidly during the gene amplification process. In this case, the sealing solution may be coated on the upper surface, the lower surface, and the like of the gene amplification chip, thereby preventing loss of the loaded sample solution. A detailed description thereof will be omitted. 
     Then, the injected sealing solution may move by capillary action toward the porous medium in operation  950 . In this case, the sealing solution moves through the upper passage, the lower passage, and the auxiliary channel formed on both sides of the upper passage, to be coated on the upper surface, the lower surface, and the like of the gene amplification chip, thereby preventing loss of the loaded sample solution. A detailed description thereof will be omitted. 
     Subsequently, while the gene amplification reaction is performed in the gene amplification chip, or after the gene amplification reaction is complete, the apparatus for detecting a microfluid may measure an optical signal from the sample solution, and may perform quantitative analysis of the amplified gene by using the measured optical signal. In this case, by emitting light of a predetermined wavelength onto the gene amplification chip using the light source of the optical unit for a predetermined period of time, the apparatus for detecting a microfluid may detect an optical signal, such as fluorescence, phosphorescence, absorbance, surface plasmon resonance, etc., radiating from the sample of the gene amplification chip, and may perform quantitative analysis of the amplified gene based on the detected optical signal and Poisson distribution. A detailed description thereof will be omitted. 
     The present invention can be realized as a computer-readable code written on a computer-readable recording medium. The computer-readable recording medium may be any type of recording device in which data is stored in a computer-readable manner. 
     Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, an optical data storage, and a carrier wave (e.g., data transmission through the Internet). The computer-readable recording medium can be distributed over a plurality of computer systems connected to a network so that a computer-readable code is written thereto and executed therefrom in a decentralized manner. Functional programs, codes, and code segments needed for realizing the present invention can be easily deduced by computer programmers of ordinary skill in the art, to which the present invention pertains. 
     The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting. The present teaching can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.