Patent Publication Number: US-8119079-B2

Title: Microfluidic apparatus having fluid container

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims priority from Korean Patent Application No. 10-2007-0055247, filed on Jun. 5, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to microfluidics, and more particularly, to a microfluidic apparatus having a fluid container in which a limitation due to the thickness of a substrate is overcome and a large amount of fluid can be accommodated. 
     2. Description of the Related Art 
     Generally, in the field of microfluidics, a microfluidic apparatus using a small amount of fluid in the field of microfluidics comprises a chamber in which the small amount of fluid is accommodated, a channel through which the fluid flows, and a valve which controls the flow of the fluid. An apparatus manufactured to perform a test, including a biochemical reaction on a small-sized chip, is referred to as a bio-chip. In particular, an apparatus manufactured to perform fluid processing and manipulation in several steps is referred to as a lab-on-a-chip. 
     A driving pressure is needed to convey a fluid in a microfluidic apparatus. A capillary pressure or a pressure caused by a separate pump is used as the driving pressure. Recently, centrifugal force-based microfluidic apparatuses, which drive a fluid by using centrifugal force generated by rotating a disc-shaped microfluidic apparatus having a chamber and a channel, have been suggested. This kind of apparatus is referred to as a Lab CD or a Lab-on-a-CD. 
     When a biochemical test is performed using the microfluidic apparatus, a large amount of a fluid is needed. For example, when a liver function test is performed, a large amount of a buffer solution corresponding to several hundreds or thousands times of a required amount of a whole blood (WB) sample, is needed. However, since generally the chamber and channel of the microfluidic apparatus are formed inside a flat substrate, the size of the substrate must be increased so as to increase the capacity of the chamber to accommodate the buffer. In addition, the arrangement of the chamber and the channel in the substrate cannot be easily performed. As a result, costs for manufacturing a microfluidic apparatus are increased and it is difficult to implement an integrated micro fluidic apparatus. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is to provide a microfluidic apparatus having a fluid container in which a limitation due to the thickness of a substrate is overcome and a large amount of fluid can be accommodated. 
     According to a non-limiting embodiment of the present invention, there is provided a microfluidic apparatus comprising: a substrate including a channel through which a fluid is conveyed; a fluid container in which at least one kind of fluid is accommodated and which is disposed on the substrate so as to allow the fluid to flow toward the channel; and a fluid flow controller which controls a flow of the fluid toward the channel from the fluid container. 
     The fluid container may be adhered to and fixed on the substrate. 
     The fluid container may be detachably attached to the substrate. 
     The microfluidic apparatus may be installed in a motor providing a rotational driving force and may be rotatable. 
     The fluid container may be disposed closer to a rotation center of the microfluidic apparatus than the channel. 
     The fluid container may further comprise a pouch in which the fluid is accommodated and which is sealed to be perforated. 
     The fluid flow controller may prevent arbitrary outflow of the fluid accommodated in the fluid container and comprise a container lid which is perforated or melted by an energy of an electromagnetic wave. 
     At least a portion of the fluid container may be transparent so that the electromagnetic wave can be incident on the container lid. 
     The container lid may comprise a thin film on which an electromagnetic wave-absorbing material is coated. 
     The thin film may be formed of metal. 
     The fluid container may be attached to the substrate to be rotated or slid on the substrate, and the fluid flow controller may comprise a container lid which prevents arbitrary outflow of the fluid accommodated in the fluid container. 
     The substrate may comprise an explosion unit which explodes the container lid by contacting the container lid when the fluid container is rotated or slid on the substrate. 
     The container lid may comprise a thin film, and the explosion unit may comprise a pin which protrudes toward the container lid. 
     The fluid container may comprise a plurality of fluid accommodation spaces in which at least two kinds of fluid are separated and accommodated, and the plurality of fluid accommodation spaces may be made to be different from one another by having different sizes, different colors or different patterns formed on the outside thereof. 
     The fluid flow controller may comprise a valve which comprise a phase transition material and is hardened at the channel to close the channel and is melted by an energy of an electromagnetic wave to open the channel. 
     The phase transition material may be a wax, a gel or a plastic resin. 
     The valve may comprise a plurality of microheating particles which are dispersed in the phase transition material and absorb an energy of an electromagnetic wave to dissipate heat. 
     The microheating particles may be micrometal oxides. 
     The micrometal oxides may be Al 2 O 3 , TiO 2 , Ta 2 O 3 , Fe 2 O 3 , Fe 3 O 4  or HfO 2 . 
     The microheating particles may be polymer particles, quantum dots or magnetic beads. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary, non-limiting embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a plan view of a microfluidic apparatus according to a non-limiting embodiment of the present invention. 
         FIGS. 2A and 2B  are cross-sectional views sequentially illustrating a fluid-conveying operation in the microfluidic apparatus of  FIG. 1 ; 
         FIG. 3  is an enlarged cross-sectional view of a container lid of  FIG. 2A ; 
         FIGS. 4A and 4B  are cross-sectional views sequentially illustrating a fluid-conveying operation in a microfluidic apparatus according to another non-limiting embodiment of the present invention; 
         FIG. 5  is an exploded perspective view of a microfluidic apparatus according to another non-limiting embodiment of the present invention; 
         FIGS. 6A and 6B  are plan views sequentially illustrating a fluid-conveying operation in the microfluidic apparatus of  FIG. 5 ; and 
         FIG. 7  is a plan view of a microfluidic apparatus according to another non-limiting embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary, non-limiting embodiments of the invention are shown. 
       FIG. 1  is a plan view of a microfluidic apparatus according to a non-limiting embodiment of the present invention,  FIGS. 2A and 2B  are cross-sectional views sequentially illustrating a fluid-conveying operation in the microfluidic apparatus of  FIG. 1 , and  FIG. 3  is an enlarged cross-sectional view of a container lid of  FIG. 2A . 
     Referring to  FIG. 1 , a microfluidic apparatus  100  according to a non-limiting embodiment of the present invention comprises a disc-shaped substrate  101  and a fluid container  140  which is attached to the substrate  101 . A chamber in which a fluid is accommodated, a channel through which the fluid is conveyed, and a valve which controls the flow of the fluid flowing along the channel are provided inside the substrate  101  (as described later). Specifically, the microfluidic apparatus  100  of  FIG. 1 , according to the current non-limiting embodiment, is used for a liver function test. A centrifugal separation unit  110  which centrifugally separates a sample such as whole blood (WB), a mixing chamber  116  in which serum extracted from the centrifugal separation unit  110  and a buffer are mixed, and a reaction chamber  118  in which a reagent reacting a particular material included in serum is accommodated are provided inside the substrate  101 . In addition, provided inside the substrate  101  are a metering chamber  112 , in which only a fixed amount of a buffer B (see  FIG. 2A ) flowing in from the fluid container  140  is accommodated so as to quantitatively supply the buffer B to the mixing chamber  116 , and a discharge chamber  114  in which a redundancy buffer is accommodated. 
     The buffer B (see  FIG. 2A ) is accommodated in the fluid container  140 . A first channel  120  in which a fluid is conveyed to the metering chamber  112  from the fluid container  140 , a second channel  125  in which the fluid is conveyed to the mixing chamber  116  from the centrifugal separation unit  110 , a third channel  130  in which the fluid is conveyed to the mixing chamber  116  from the metering chamber  112 , a fourth channel  135  in which the fluid is conveyed to the reaction chamber  118  from the mixing chamber  116 , and a fifth channel  139  in which the fluid is conveyed to the discharge chamber  114  from the metering chamber  112 , are provided inside the substrate  101 . Valves  126 ,  131 , and  136  which control the flow of the fluid are provided in the second through fourth channels  125 ,  130 , and  135 . The valves  126 ,  131 , and  136  are so-called ‘normally closed valves’ which normally close the channels  125 ,  130 , and  135  and only open them under predetermined conditions. However, the microfluidic apparatus according to the present invention is not limited to the arrangement shape of the chamber, the channel, and the valve of  FIG. 1  and may be designed in various shapes according to particular usages in the field of biochemistry such as immunoassay or gene analysis. 
     The microfluidic apparatus  100  is installed in a spindle motor  50  which provides a rotation driving force. When the microfluidic apparatus  100  is rotated by the operation of the spindle motor  50 , a centrifugal force-based pressure is applied to the fluid inside the substrate  101  and the fluid container  140  so that conveying or mixing of the fluid is promoted. 
     Referring to  FIGS. 2A and 2B , the substrate  101  comprises an upper plate  102  and a lower plate  103  which are adhered to each other. The upper plate  102  and the lower plate  103  may be adhered to each other by ultrasonic wave fusion or by interposing double-sided adhesive tape between the upper and lower plates  102  and  103 . The upper plate  102  and the lower plate  103  may be manufactured by injection molding a plastic resin. The fluid container  140  comprises a fluid accommodation space  142  in which a fluid such as a buffer B is accommodated. The fluid container  140  is manufactured by injection molding the plastic resin and is adhered to and fixed in the substrate  101 . The fluid container  140  in which the fluid B is accommodated is sealed by a container lid  150 . Specifically, the fluid container  140  is turned over, the fluid B is injected into the fluid accommodation space  142 , and the container lid  150  is adhered to an aperture circumferential portion  143  of the fluid container  140  so that outflow of the fluid can be prevented. Then, the fluid container  140  is adhered to and fixed in the substrate  101  so that a groove portion  105  formed to be near the spindle motor  50  and the container lid  150  face each other. 
     The present invention is not limited to the non-limiting embodiment of  FIG. 2A , and unlike  FIG. 2A , a fluid pouch in which a fluid is accommodated and is initially sealed to be later perforated or melted may be provided inside the fluid container. 
     The groove portion  105  is connected to the first channel  120 , and the groove portion  105  and the fluid container  140  that overlaps with the groove portion  105  are more near a rotation center C than the first channel  120 . The fluid container  140  is adhered to the substrate  101  to be protruded toward a higher position than the upper side of the substrate  101 , and in order to increase the accommodation amount of the fluid B, a height H 2  of the fluid accommodation space  142  is set to be larger than a thickness H 1  of the substrate  101 . 
     The container lid  150  constitutes a fluid flow controller which controls the flow of the fluid B directing toward the channel  120  from the fluid container  140 . The container lid  150  prevents arbitrary outflow of the fluid B accommodated in the fluid accommodation space  142  and is perforated or melted by an energy of an electromagnetic wave L, such as laser, that is incident from an external energy source  60 . 
     Specifically, referring to  FIG. 3 , the container lid  150  comprises a metallic thin film  151  and an electromagnetic wave-absorbing layer  152  stacked on the thin film  151 . The electromagnetic wave-absorbing layer  152  is formed by coating an electromagnetic wave-absorbing material on the metallic thin film  151 . Due to the electromagnetic wave-absorbing layer  152 , the container lid  150  absorbs the electromagnetic wave L that is projected from an energy source  60  and is perforated or melted. The thin film  151  may be formed of another material such as polymer as well as metal, that can be perforated or melted by irradiating the electromagnetic wave L. 
     Referring to  FIG. 2A , the energy source  60  may comprises a laser light source which projects a laser, and the laser light source may comprise at least one laser diode (LD). At least a portion of the fluid container  140  is transparent so that the electromagnetic wave L projected from an outside of the fluid container  140  can pass through the fluid container  140  and can be irradiated onto the container lid  150 . 
     When the electromagnetic wave L is irradiated onto the container lid  150  using the energy source  60  for a predetermined time, the container lid  150  is perforated or melted as shown in  FIG. 2B . When the microfluidic apparatus  100  in which the container lid  150  is perforated or melted is rotated by the spindle motor  50 , the fluid B (see  FIG. 2A ) accommodated in the fluid accommodation space  142  passes through the groove portion  105  and the first channel  120 , moves to the metering chamber  112  and is accommodated in the metering chamber  112  (see  FIG. 2B ). A redundancy fluid B that is not accommodated in the metering chamber  112  passes through the fifth channel  139  (see  FIG. 1 ) and is accommodated in the discharge chamber  114  (see  FIG. 1 ). 
       FIGS. 4A and 4B  are cross-sectional views sequentially illustrating a fluid-conveying operation in a microfluidic apparatus according to another non-limiting embodiment of the present invention. 
     Referring to  FIGS. 4A and 4B , a microfluidic apparatus  200  according to another non-limiting embodiment of the present invention comprises a disc-shaped substrate  201  and a fluid container  240  which is attached to the substrate  201 . A chamber  212  in which a fluid B is accommodated, channels  220  and  230  through which the fluid B is conveyed, and valves  221  and  231  which control the flow of the fluid B along the channels  220  and  230  are provided inside the substrate  201 . The chamber  212  is a metering chamber in which only a fixed amount of the fluid B flowed in from the fluid container  240  is accommodated so as to quantitatively supply the fluid B to a mixing chamber (not shown)  116 . 
     The microfluidic apparatus  200  is installed in the spindle motor  50  which provides a rotation driving force. When the microfluidic apparatus  200  is rotated by the operation of the spindle motor  50 , a centrifugal force-based pressure is applied to the fluid inside the substrate  201  and the fluid container  240  so that conveying or mixing of the fluid is promoted. 
     The substrate  201  comprises an upper plate  202  and a lower plate  203  which are adhered to each other. The upper plate  202  and the lower plate  203  may be adhered to each other by ultrasonic wave fusion or by interposing double-sided adhesive tape between the upper and lower plates  202  and  203 . The upper plate  202  and the lower plate  203  may be manufactured by injection molding a plastic resin. The fluid container  240  comprises a fluid accommodation space  242  in which the fluid B is accommodated. The fluid container  240  is manufactured by injection molding the plastic resin and is adhered to and fixed in the substrate  201 . 
     A fluid injection hole  245  is formed in the fluid container  240  and the fluid B can be injected into the fluid accommodation space  242  through the fluid injection hole  245 . 
     When the fluid B is accommodated in the fluid accommodation space  242 , the fluid injection hole  245  is closed by a closing means such as adhesive tape  247 . 
     The fluid container  240  is disposed to be more near to a rotation center C than the first channel  220 . 
     The fluid container  240  is adhered to the substrate  201  to protrude to a higher position than the upper side of the substrate  201 . In the microfluidic apparatus  200  of  FIGS. 4A and 4B , the fluid container  240  is separately formed from the upper plate  202  and is attached to the upper plate  202 . However, the present invention is not limited to this and the fluid container  240  may also be formed together with the upper plate  202  by plastic resin injection molding. 
     The valve  221  provided in the channel  220  between the fluid container  240  and the metering chamber  212  constitutes a fluid flow controller which controls the flow of the fluid B toward the channel  220  from the fluid accommodation space  242 . The valve  221  prevents arbitrary leakage of the fluid B accommodated in the fluid accommodation space  242  and is exploded and melted by an energy of an electromagnetic wave L, such as a laser, that is incident from an external energy source  60 . 
     The valve  221  is a so-called ‘normally closed valve’ which closes the channel  220  so that the fluid B cannot be flowed through the valve  221  before the valve  221  absorbs an electromagnetic wave energy. The valve  221  comprises a phase transition material that is melted by the electromagnetic wave energy and a plurality of microheating particles which are dispersed in the phase transition material and absorb the electromagnetic wave energy and dissipate heat. The phase transition material may be a wax. When the wax is heated, it is melted and is changed into a liquid state and its volume expands. For example, the wax may be a paraffin wax, a microcrystalline wax, a synthetic wax or a natural wax etc. The phase transition material may also be a gel or plastic resin. Polyacrylamide, polyacrylates, polymethacrylates or polyvinylamides may be used as the gel. In addition, cyclic olefin copolymer (COC), polymethylmethacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyoxymethylene (POM), perfluoralkoxy (PEA), polyvinylchloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyamide (PA), polysulfone (PSU), and polyvinylidene fluoride (PVDF) may be used as the plastic resin. 
     The microheating particles have a diameter of 1 nm to 100 μm so that they can freely pass through the microchannel  220  having a depth of approximately 0.1 mm and a width of 1 mm. The microheating particles have a characteristic that the temperature of the microheating particles increases rapidly and the microheating particles dissipate heat when the electromagnetic wave energy is supplied to the microheating particles using a method such as irradiating of a laser L. The microheating particles can be dispersed in the wax. To this end, the microheating particles may comprise a core including metal components and a hydrophobic surface structure. For example, the microheating particles may have a molecular structure comprising a core formed of Fe and a plurality of surfactants combined with Fe and surrounding Fe. In general, the microheating particles are kept in a state where they are dispersed in a carrier oil. The carrier oil may be hydrophobic so that the microheating particles having a hydrophobic surface structure can be uniformly dispersed in the carrier oil. The carrier oil in which the microheating particles are dispersed is poured into and mixed with the melted phase transition material so that a material for forming the valve  221  can be formed. 
     The microheating particles are not limited to polymer particles and may be quantum dot-shaped or magnetic bead-shaped. In addition, the microheating particles may be micrometal oxides such as Al 2 O 3 , TiO 2 , Ta 2 O 3 , Fe 2 O 3 , Fe 3 O 4 , and HfO 2 . The valve  221  may also be formed of only the phase transition material without the microheating particles. The valve  231  that is provided in the other channel  230  is also formed of a phase transition material and a plurality of microheating particles dispersed therein, like the above-described valve  221 . Thus, a repeated description of the valve  231  will be omitted. At least a portion of the substrate  201  is transparent so that the electromagnetic wave L projected from the outside of the substrate  201  can be irradiated onto the valves  221  and  231 . 
     When the electromagnetic wave L is irradiated onto the valve  221  formed between the fluid container  240  and the metering chamber  212 , using the energy source  60 , the microheating particles included in the valve  221  dissipate heat rapidly and the phase transition material is rapidly heated. Thus, the valve  221  is rapidly melted, the channel  220  is opened, and the fluid B flows through the channel  220 . When the microfluidic apparatus  200 , in which the valve  221  is melted, drives and rotates the spindle motor  50 , a fluid B (see  FIG. 4A ) accommodated in the fluid accommodation space  242  passes through the channel  220  and moves to the metering chamber  212  and is accommodated in the metering chamber  212  (see  FIG. 4B ). 
       FIG. 5  is an exploded perspective view of a microfluidic apparatus according to another non-limiting embodiment of the present invention, and  FIGS. 6A and 6B  are plan views sequentially illustrating a fluid-conveying operation in the microfluidic apparatus of  FIG. 5 . 
     Referring to  FIG. 5 , a microfluidic apparatus  300  according to another non-limiting embodiment of the present invention comprises a disc-shaped substrate  301  and a fluid container  340  which is detachably installed in the substrate  301 . First and second chambers  312  and  314  in which a fluid B is accommodated and first and second channels  320  and  339  through which the fluid B is conveyed are provided inside the substrate  301 . 
     The microfluidic apparatus  300  is installed in the spindle motor  50  which provides a rotation driving force. When the microfluidic apparatus  300  is rotated by the operation of the spindle motor  50 , a centrifugal force-based pressure is applied to the fluid B inside the substrate  301  and the fluid container  340  so that conveying or mixing of the fluid is promoted. 
     A groove portion  370  is formed at a circumferential portion of the center of the substrate  301  in which the spindle motor  50  is inserted. A lower end portion of the fluid container  340  is detachably formed in the groove portion  370 . The groove portion  370  is connected to the first channel  320  and is disposed to be more near the center of the substrate  301  than the first channel  320 . 
     The substrate  301  comprises an upper plate  302  and a lower plate  303  which are adhered to each other. The upper plate  302  and the lower plate  303  may be adhered to each other by ultrasonic wave fusion or by interposing double-sided adhesive tape between the upper and lower plates  302  and  303 . The upper plate  302  and the lower plate  303  may be manufactured by injection molding a plastic resin. 
     The fluid container  340  comprises a fluid accommodation space  342  in which the fluid B is accommodated. The fluid container  340  is manufactured by injection molding a plastic resin. The fluid container  340  in which the fluid B is accommodated is sealed by a container lid  350 . Specifically, the fluid container  340  is turned over, the fluid B is injected into the fluid accommodation space  342 , and the container lid  350  is adhered to an aperture circumferential portion  343  of the fluid container  340  so that outflow of the fluid can be prevented. The container lid  350  may comprise a thin film formed of metal etc. Four outer connection flanges  345  and two inner connection flanges  346  are disposed at a lower end portion of the fluid container  340 . Four outer connection flange accommodation portions  371  in which the outer connection flanges  345  are accommodated and two inner connection flange accommodation portions  374  in which the inner connection flanges  346  are accommodated are disposed at circumferential portions of the groove portion  370 . 
     Clearances  372  and  375  are formed in the outer and inner connection flange accommodation portions  371  and  374  so that the outer and inner connection flanges  345  and  346  can move in the outer and inner connection flange accommodation portions  371  and  374  within a predetermined range. As such, the fluid container  340  can be rotated by a predetermined angle in a state where it is installed in the groove portion  370  of the substrate  301 . 
     When the outer and inner connection flanges  345  and  346  are inserted in the accommodation portions  371  and  374  and the fluid container  340  is slightly rotated counterclockwise, the outer and inner connection flanges  345  and  346  move to the clearances  372  and  375  and are covered in the upper plate  320 , the fluid container  340  is attached to the substrate  301  so as not to be arbitrarily separated from the substrate  301 . The fluid container  340  is attached to the substrate  301  to protrude to a higher position than the upper side of the substrate  301 . The substrate  301  further comprises an explosion unit which explodes the container lid  350 . The explosion unit comprises a pin  377  which is formed in the groove portion  370  and protrudes toward the upper side of the substrate  301 . However, the explosion unit according to the present invention is not limited to the pin  377  of  FIG. 5 , and a needle having a sharp edge or a cutter may be used as the explosion unit. In addition, an energy source which irradiates an electromagnetic wave may also be used as the explosion unit. 
       FIG. 6A  illustrates the state where the outer and inner connection flanges  345  and  346  are inserted in the outer and inner connection flange accommodation portions  371  and  374  (see  FIG. 5 ) so as to install the fluid container  340  in the substrate  301 . At this time, a small hole may be perforated in the container lid  350  (see  FIG. 5 ) by the pin  377  that protrudes toward the substrate  301 .  FIG. 6B  illustrates the state where the fluid container  340  is slightly rotated counterclockwise from the state of  FIG. 6A  and is fixed in the substrate  301  not to be separated from the substrate  301 . Since the container lid  350  moves about the pin  377  by rotation of the fluid container  340 , the small hole formed by the pin  377  is enlarged and the container lid  350  is broken. Reference numeral T of  FIG. 6B  denotes a portion in which the container lid  350  is broken by the pin  377 . The microfluidic apparatus  300  according to another non-limiting embodiment of the present invention comprises the fluid container  340  that can be rotated by a predetermined angle with respect to the substrate  301 . However, the present invention is not limited to this and may comprise a fluid container that can be slid on the substrate, for example. 
     Referring to  FIG. 5 , when the container lid  350  is broken and the microfluidic apparatus  300  is rotated by the spindle motor  50 , the fluid B accommodated in the fluid container  340  passes through the groove portion  370  and the first channel  320  and moves to the first chamber  312  and is accommodated therein. Redundant fluid that is not accommodated in the first chamber  312  passes through the second channel  339  and is accommodated in the second chamber  314 . 
       FIG. 7  is a plan view of a microfluidic apparatus according to another non-limiting embodiment of the present invention. 
     Referring to  FIG. 7 , a microfluidic apparatus  400  according to another non-limiting embodiment of the present invention comprises a disc-shaped substrate  401  and a fluid container  440  which is attached to the substrate  401 . The fluid container  440  comprises a plurality of fluid accommodation spaces  342 ,  343 ,  344 , and  345 . 
     The plurality of fluid accommodation spaces  342 ,  343 ,  344 , and  345  are made to be different from one another such that confusion does not occur when a fluid is injected in each fluid accommodation space. Specifically, in this embodiment, the sizes of the first through fourth fluid accommodation spaces  342 ,  343 ,  344 , and  345  are different from one another. In  FIG. 7 , a region inside a dotted line denotes each fluid accommodation space. In addition, the first fluid accommodation space  342  and the second fluid accommodation unit  343  are different from each other because different colors are coated on outer sides of the first and second fluid accommodation spaces  342 . In  FIG. 7 , hatching of the first and second fluid accommodation spaces  342  and  343  denote different colors. In addition, different patterns are formed on the outside of the third fluid accommodation space  344  and the fourth fluid accommodation space  345  so that the third and fourth fluid accommodation spaces  344  and  345  are different from each other. 
     For example, a star-shaped pattern is formed in the third fluid accommodation space  344 , and a triangular pattern is formed in the fourth fluid accommodation space  345 . Although not shown in  FIG. 7 , like embodiments shown in other drawings, the microfluidic apparatus  400  according to another non-limiting embodiment of the present invention comprises a channel through which a fluid is conveyed and a fluid flow controller which controls the flow of the fluid accommodated in the fluid accommodating spaces  342 ,  343 ,  344 , and  344 , which are provided inside the substrate  401 . 
     The microfluidic apparatus according to the present invention may comprise a fluid container which is not limited by the thickness of a substrate and in which a large amount of fluid is accommodated. Thus, the substrate does not need to be increased so as to increase the capacity of the fluid container and the arrangement of the chamber and the channel in the substrate can be easily performed. As a result, costs for manufacturing the microfluidic apparatus can be reduced and an integrated microfluidic apparatus can be easily performed. 
     While the present invention has been particularly shown and described with reference to exemplary, non-limiting embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.