Microfluidic device using centrifugal force and pump to control fluid movement, microfluidic system comprising the same and method of manufacturing the microfluidic device

The microfluidic device includes a rotatable platform, a plurality of connection ports disposed at a portion of the platform proximate to a shaft connection hole, the plurality of connection ports capable of being connected to an external connector for selectively injecting and discharging fluid and being closed by the connector, a trap chamber disposed at a portion of the platform further away from the shaft connection hole than the plurality of connection ports, the trap chamber including an inlet connected with at least one connection port of the plurality of connection ports, an outlet connected with another connection port of the plurality of connection ports and structures which enlarge a contact area with the fluid and a temporary storage including an inlet connected with the outlet of the trap chamber and an outlet connected with another connection port of the plurality of connection ports.

This application claims priority to Korean Patent Application No. 10-2006-0123393, filed on Dec. 6, 2006, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a microfluidic device which controls a fluid movement and a microfluidic system comprising the same, and more particularly, to a microfluidic device employing a fluid movement using centrifugal force and a fluid movement using a pump, and a microfluidic system comprising the same.

2. Description of the Related Art

A microfluidic device includes a chamber which stores a minute amount of fluid, a channel through which the fluid flows and a valve which controls fluid flow. A biochip is formed by arranging such microfluidic devices on a chip-type substrate and is used to analyze a performance of various assays, including biological reactions. Particularly, a device that is designed to perform multiple step processes and manipulations using a single chip is called a lab-on-a chip (“LOC”).

A driving pressure is generally required in order to transfer the fluid within a microfluidic device. A capillary pressure or a pressure generated by a specifically prepared pump is used as the driving pressure. A lab compact disk (“CD”) is a recently introduced microfluidic device which is formed by arranging microfluidic structures on a compact disk-shaped platform and which uses centrifugal force. In a case of a microfluidic device using centrifugal force to control a fluid movement, the fluid movement is limited to an outward direction from a rotation shaft. Therefore, a chamber where a fluid movement starts, such as a sample chamber, should be disposed at a portion of the microfluidic device proximate to the rotation shaft. However, it is difficult to obtain an area close to the rotation shaft for mounting chamber structures having a large volume because the portion of the microfluidic device proximate to the rotation shaft has a relatively small area, as compared to a portion further away from the rotation shaft. Also, a rotation speed of the microfluidic device should be limited such that a valve can resist the rotation of the microfluidic device or such that a channel can serve as a valve during a fluid movement.

In a case of the microfluidic device using a pump to move a fluid, it is difficult to collect a solution which remains between pillars or beads by using a capillary force in a trap chamber which includes a plurality of pillar structures or packed beads.

BRIEF SUMMARY OF THE INVENTION

An exemplary embodiment of the present invention provides a microfluidic device employing a fluid movement using centrifugal force and a fluid movement using a pump, and a microfluidic system including the same.

An exemplary embodiment of the present invention also provides a disk-shaped microfluidic device which efficiently uses a relatively large area further from a shaft connection hole of the disk-shaped microfluidic device by using a centrifugal force in order to control a fluid movement and which allows a fluid movement in an inward direction from a perimeter of the microfluidic device and thus does not require a valve between chambers, thereby removing a limitation of rotation speed due to a weak valve.

According to an exemplary embodiment of the present invention, there is provided a microfluidic device including a rotatable platform, a plurality of connection ports disposed at a portion of the platform proximate to a shaft connection hole disposed in the platform, the plurality of connection ports capable of being connected to an external connector for selectively injecting and discharging fluid and being closed by the external connector, a trap chamber disposed at a portion of the platform further away from the shaft connection hole than the plurality of connection ports, the trap chamber including an inlet, an outlet and structures, the inlet connected with at least one connection port of the plurality of connection ports, the outlet connected with another connection port of the plurality of connection ports and the structures enlarge a contact area with the fluid and a temporary storage disposed at a portion of the platform further away from the shaft connection hole than the trap chamber, the temporary storage including an inlet and an outlet, the inlet connected with the outlet of the trap chamber and the outlet connected with another connection port of the plurality of connection ports, and the temporary storage stores the fluid discharged from the trap chamber by centrifugal force during a rotation of the platform.

In an exemplary embodiment, the rotatable platform may be disk-shaped.

In an exemplary embodiment, the structures in the trap chamber may be a plurality of packed beads. However, the present invention is not limited thereto, and the structures may be structures of various shapes, for example, a pillar-shape.

In exemplary embodiments, the structures such as beads may include surfaces coated with a material to which a specific material can be attached among materials contained within a fluid and thus may detach or concentrate the specific material contained within a fluid.

In exemplary embodiments, the temporary storage may be configured in a chamber or a channel and include a volume larger than or equal to an effective volume of the trap chamber, except for a volume of the internal structures in the trap chamber.

In exemplary embodiments, the plurality of connection ports, the trap chamber and the temporary storage may be connected with each other through channels.

In exemplary embodiments, the microfluidic device may further include a sample chamber disposed at a portion of the platform further away from the shaft connection hole than the plurality of connection ports, wherein an inlet of the sample chamber is connected with one connection port of the plurality of connection ports and an outlet of the sample chamber is connected with the inlet of the trap chamber, and the sample chamber stores a fluid sample therein.

According to another exemplary embodiment of the present invention, there is provided a microfluidic device including a rotatable platform, a plurality of connection ports disposed at a portion of the platform proximate to a shaft connection hole disposed in the platform, the plurality of connection ports capable of being opened for selectively injecting or discharging fluid through a connection with an external connector, or being closed and a plurality of trap chamber modules, wherein each trap chamber module of the plurality of trap chamber modules includes a trap chamber disposed at a portion of the platform further away from the shaft connection hole than the plurality of connection ports, the trap chamber including an inlet, an outlet and structures, the inlet connected with at least one connection port of the plurality of connection ports, the outlet connected with another connection port of the plurality of connection ports and the structures enlarge a contact area with the fluid and a temporary storage disposed at a portion of the platform further away from the shaft connection hole than the trap chamber, the temporary storage including an inlet and an outlet, the inlet connected with the outlet of the trap chamber and the outlet connected with another connection port of the plurality of connection ports, and the temporary storage stores the fluid discharged from the trap chamber by centrifugal force during a rotation of the platform, wherein an outlet of the temporary storage of an upstream trap chamber module is connected with an inlet of the trap chamber of a downstream trap chamber module corresponding to a movement direction of the fluid.

In an exemplary embodiment, the structures in the trap chamber may be a plurality of packed beads. However, the present invention is not limited thereto, and the structures may be structures of various shapes, for example, a pillar-shape. In an exemplary embodiment, the structures such as beads may include surfaces coated with a material to which a specific material can be attached among materials contained within the fluid and thus may detach or concentrate the specific material contained within the fluid.

In an exemplary embodiment, the temporary storage may be configured in a chamber or a channel and have a volume larger than or equal to an effective volume of the trap chamber, except for a volume of the structures in the trap chamber.

In an exemplary embodiment, the plurality of connection ports, the trap chamber and the temporary storage may be connected with each other through channels.

In an exemplary embodiment, the microfluidic device may further include a sample chamber disposed at a portion of the platform further away from the shaft connection hole than the plurality of connection ports, wherein an inlet of the sample chamber is connected with one connection port of the plurality of connection ports and an outlet of the sample chamber is connected with the inlet of the trap chamber of a most upstream trap chamber module among the plurality of trap chamber modules, and the sample chamber stores a fluid sample therein.

According to another exemplary embodiment of the present invention, there is provided a microfluidic system including one microfluidic device of the above-mentioned microfluidic devices, a rotating mount which controls a rotation speed and an angular position while supporting the microfluidic device and a connector including a plurality of connection passages respectively corresponding to the plurality of connection ports disposed in the microfluidic device, and pipes and valves respectively connected with the plurality of connection passages, the connector capable of being connected with and separated from the plurality of connection ports of the microfluidic device, wherein the connector is connected with the plurality of connection ports of the microfluidic device when moving fluid in the microfluidic device using an external pump, fluid that is pressurized by using the external pump is injected into at least one connection passage of the plurality of connection passages and remaining connection passages of the plurality of connection passages are selectively opened or closed using the respective valves, and the connector is separated from the microfluidic device when moving fluid in the microfluidic device by using centrifugal force.

According to another exemplary embodiment of the present invention, there is provided a method of manufacturing the above-mentioned microfluidic devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates a schematic top plan view of an exemplary embodiment of a microfluidic device101according to the present invention. The microfluidic device101includes a microfluidic structure including a plurality of channels and chambers formed in a disk-shaped platform10. In exemplary embodiments, the platform10may be formed of a plastic material such as polycarbonate (“PC”). The technology for forming microfluidic structures, such as channels, chambers and the like is well known in the art. In exemplary embodiments, a shaft connection hole11may be formed in a center or a central portion of the platform10, and a rotation shaft (not shown) may be inserted into the shaft connection hole11. The rotation shaft (not shown) and the shaft connection hole11may be engaged with each other so as to allow the platform10to smoothly rotate on the rotation shaft. An align key13is formed in at least a portion of the platform10. The align key13provides data about a current angular position such that the microfluidic device101can be aligned at a desired angular position.

Referring toFIG. 1, a plurality of connection ports22,23and24are formed proximate to the shaft connection hole11formed in the platform10. A trap chamber120is disposed further away from the shaft connection hole11than the plurality of connection ports22,23and24. The trap chamber120includes structures in order to enlarge a contact area with a fluid. A temporary storage130is disposed further away from the shaft connection hole11than the trap chamber120in order to store fluid discharged from the trap chamber120, when using a centrifugal force. In exemplary embodiments, the internal structures of the trap chamber120may be a plurality of packed beads40. However, the present invention is not limited thereto, and the internal structures of the trap chamber120may be a plurality of pillar-shaped structures. An inlet of the trap chamber120is connected with the connection port22through an injection channel121, an outlet of the trap chamber120is connected with an inlet of the temporary storage130through an intermediate channel122and the intermediate channel122is connected with the connection port23through an intermediate discharge channel123. An outlet of the temporary storage130is connected with the connection port24through a discharge channel133. The temporary storage130temporarily stores fluid when the fluid filled in the trap chamber120is discharged by centrifugal force. In exemplary embodiments, the temporary storage130may be a chamber or a channel, provided that the temporary storage130includes a space which can sufficiently receive the fluid filled in the trap chamber120.

An operation of the microfluidic device101according to the current exemplary embodiment will now be described. A fluid sample is injected into the connection port22which is connected to the inlet of the trap chamber120by using a pump when the microfluidic device101is stopped. Here, when the connection port23which is connected to the intermediate discharge channel123is opened, and the connection port24which is connected to the discharge channel133is closed, the fluid sample passing through the trap chamber20flows into the connection port23through the intermediate discharge channel123.

When the microfluidic device101is rotated in a state where the fluid sample is filled in the trap chamber120, the fluid sample moves into the temporary storage130by centrifugal force. When the microfluidic device101is stopped and air is injected into the connection port22by using a pump while closing the connection port23, which is connected with the intermediate discharge channel123, the fluid sample which is stored in the temporary storage130is thereby discharged through the discharge channel133and through the connection port24, which is connected with the discharge channel133.

In exemplary embodiments, the centrifugal force, as described above, may be used in a section where the use of the centrifugal force is favorable to a fluid movement, for example, a section where fluid is discharged from the trap chamber120to the temporary storage130, and the fluid sample may be moved by injecting the fluid sample or air into the connection ports22,23and24in other sections.

FIG. 2illustrates a schematic top plan view of another exemplary embodiment of a microfluidic device102according to the present invention. The microfluidic device102includes a same configuration as the microfluidic device101, except that the microfluidic device102further includes a sample chamber110. An inlet of the sample chamber110is connected with a connection port21through an injection channel111and an outlet of the sample chamber110is connected with the inlet of the trap chamber120. In an exemplary embodiment, the outlet of the sample chamber110is connected with the injection channel121of the trap chamber120, through the discharge channel113.

In exemplary embodiments, the sample chamber110may be disposed proximate to a circumference of the microfluidic device102, that is, a portion of the microfluidic device102which has more space, as compared to a portion closer to the shaft connection hole11. In exemplary embodiments, a fluid sample may be injected into the sample chamber110through the connection port21which is connected with the injection channel111. When air is injected into the sample chamber110through the connection port21in a state where the fluid sample is filled in the sample chamber110, the fluid sample moves into the trap chamber120through the discharge channel113. In the current exemplary embodiment, the connection port22which is connected with the injection channel121of the trap chamber120may be closed in order to prevent leakage of the fluid sample.

FIG. 3illustrates a schematic top plan view of another exemplary embodiment of a microfluidic device103according to the present invention. The microfluidic device103includes first and second trap chamber modules301and302, respectively, in a platform10. The first and second trap chamber modules301and302include trap chambers150and170, temporary storages160and180, a plurality of connection ports32to36and a plurality of channels151,152,153,163,171,172,173and183for connecting the above-mentioned structures with each other, respectively. Each of the trap chamber modules301and302includes a same configuration as the microfluidic structure described with respect to the microfluidic device101, as illustrated inFIG. 1. A discharge channel163of the first trap chamber module301is connected with an inlet of the trap chamber170of the second trap chamber module302. In an exemplary embodiment, the discharge channel163of the first trap chamber module301is connected with an injection channel171which connects the trap chamber170with the connection port34. In the current exemplary embodiment, the microfluidic device103includes the two trap chamber modules301and302, however the present invention is not limited thereto and more trap chamber modules may be arranged in series. The phrase “series arrangement” means that an outlet of an upstream module is connected with an inlet of a downstream module. For example, an outlet of the chamber module301is connected with an inlet of the chamber module302.

An exemplary embodiment of an operation of the microfluidic device103will now be described. A fluid is discharged from the first trap chamber module301through the discharge channel163according to a same process as that described with reference to the first embodiment, i.e., microfluidic device101. However, the discharged fluid is transferred into the trap chamber170of the second trap chamber module302, and is not discharged to the connection port34.

FIG. 4illustrates a schematic top plan view of another exemplary embodiment of a microfluidic device104according to the present invention. The microfluidic device104includes a same configuration as the microfluidic device103, except that the microfluidic device104further includes a sample chamber190. An inlet of the sample chamber190is connected with a connection port31through an injection channel191and an outlet of the sample chamber190is connected with the inlet of the trap chamber150of the first trap chamber module301through a discharge channel193. In an exemplary embodiment, the outlet of the sample chamber190is connected with the injection channel151of the trap chamber150.

Hereinafter, a process of extracting bacteria DNA from saliva using the microfluidic device104will be described as an exemplary embodiment of an operation of the microfluidic device according to the present invention. For convenience of description and understanding, the connection port31which is connected with the injection channel191of the sample chamber190will be referred to as the first port31, and the ports32to36will be referred to as the second port32through the sixth port36, in clockwise order. Also, the trap chamber150of the first trap chamber module301will be referred to as the first trap chamber150, and the trap chamber170of the second trap chamber module302will be referred to as the second trap chamber170. The other elements will be referred to in the same way as discussed above.

In the current exemplary embodiment, surfaces of beads41disposed in the first trap chamber150are processed such that they can be specifically bound with bacteria, and surfaces of beads42in the second trap chamber170are processed such that they can be specifically bound with DNA of bacteria.

Saliva is injected into the sample chamber190through the first port31. Next, air is injected into the first port31using a pump in order to transfer the saliva in the sample chamber190into the first trap chamber150. Here, the second port32and the fourth port34are closed, and the third port33is opened, thereby allowing the saliva passing through the first trap chamber150to be discharged through the first intermediate discharge channel153. Bacteria included in the saliva are attached onto surfaces of the beads41in the first trap chamber150through such a process.

Next, a washing buffer is injected into the second port32by using a pump. Here, all of the ports, except for the second and third ports32and33, are closed, and thus the washing buffer which passes through the first trap chamber150is discharged through the first intermediate discharge channel153. Other components of the saliva are washed out, except for the bacteria which are attached onto the surfaces of the beads41.

A lysis buffer then is injected into the first trap chamber150in the same manner as the washing buffer injection. After cell membranes of the bacteria are destroyed by the lysis buffer, a cell solution disposed in the first trap chamber150is then transferred to the first temporary storage160through the first intermediate channel152by using centrifugal force while rotating the microfluidic device104.

Next, the cell solution which is stored in the first temporary storage160is then transferred into the second trap chamber170by using a pump when the microfluidic device104is stopped. Here, air is injected into the second port32and the remaining ports, except for the fifth port35, are closed, and thus the cell solution which passes through the second trap chamber170is discharged through the second intermediate discharge channel173. DNA of bacteria contained in the cell solution is then attached onto surfaces of the beads42disposed in the second trap chamber170through such a process.

A washing buffer is then injected into the fourth port34by using a pump. Here, the remaining ports are closed, except for the fourth and fifth ports34and35, and thus the washing buffer which passes through the second trap chamber170is discharged through the second intermediate discharge channel173. Other components of the cell solution, except for the DNA of the bacteria which are attached onto the surfaces of the beads42, are washed out through such a process.

An elution buffer is then injected into the second trap chamber170in the same manner as the washing buffer injection. The DNA attached onto the surfaces of the beads42disposed in the second trap chamber170is eluted with the elution buffer. After the DNA is eluted, the cell solution in the second trap chamber170is transferred into the second temporary storage180through the second intermediate channel172by using centrifugal force while rotating the microfluidic device104.

Next, a DNA solution which is stored in the second temporary storage180is discharged through the second discharge channel183by using a pump when the microfluidic device104is stopped. Here, air is injected into the fourth port34and the remaining ports, except for the sixth port36, are closed.

FIG. 5illustrates an exemplary embodiment of a microfluidic system200wherein a fluid movement is controlled by using centrifugal force according to the present invention, andFIG. 6illustrates the exemplary embodiment of a microfluidic system200wherein a fluid movement is controlled by using a pump according to the present invention. The microfluidic system200according to the current exemplary embodiment of the present invention includes one microfluidic device of the microfluidic devices101to104, a rotating mount50and a connector60. The rotating mount50controls a rotation speed and an angular position while supporting the microfluidic device. The connector60includes a plurality of connection passages61which respectively correspond to a plurality of connection ports20which are formed in the microfluidic device, and pipes83and valves81respectively connected with the plurality of connection passages61. The connector60is capable of being connected with or separated from the connection ports20of the microfluidic device. In an exemplary embodiment, a center or a central portion of the rotating mount50may protrude in order to be inserted into the shaft connection hole11which is formed at a center or a central portion of the platform10. In exemplary embodiments, the microfluidic system200of the present invention may include a position detector70which detects a position of the align key13, which is disposed at a side of the platform10, in order to detect an angular position of the microfluidic device.

According to the current exemplary embodiment, the connector60is capable of being connected with or separated from the connection ports20of the microfluidic device by moving downward and upward, respectively. In an exemplary embodiment, a sealing member62may be disposed at a portion of the connector60which contacts each connection port20such that a fluid does not leak out when each connection port20is connected with each corresponding connection passage61. In an exemplary embodiment, the valves81are provided for the connection passages61of the connector60, and the valves81may be independently opened and closed. Fluid90which is pressurized by a pump80may be provided to the pipes83which are connected with the valves81. In exemplary embodiments, the pressurized fluid90may be a liquid or a gas.

According to an exemplary embodiment of a microfluidic device and a microfluidic system of the present invention, a fluid can move using a centrifugal force in a disk-shaped microfluidic device, furthermore, the fluid can move in an inward direction toward a central portion of the microfluidic device from a portion proximate to an outer perimeter thereof, and thereby effectively utilizing a relatively large area further away from the central portion. In addition, since additional valves for controlling a fluid movement between chambers is not required, there is no limitation in a rotation speed due to an operating condition of a capillary valve and the like during the fluid movement.