KR20130117309A - Bubble manipulation apparatus using ewod and micro-object manipulation method thereby - Google Patents

Abstract

PURPOSE: A bubble control technology and a micro material control method using the same are provided to control the location and movement of a micro material under a water environment. CONSTITUTION: An upper layer (10) includes an electrode (12), a dielectric layer (13), and a hydrophobic layer (14). The electrode controls the location or movement of bubble (30) with an EWOD method. The one surface of a glass wafer (11) is coated and forms a dielectric layer. A lower layer (20) includes a wafer (21), a ground layer (22), and a hydrophobic layer (24). Liquid is included between the upper layer and the lower layer.

Description

Bubble control apparatus using EOD and micro object control method using the same {Bubble manipulation apparatus using EWOD and micro-object manipulation method

The present invention relates to a bubble control device by EWOD and a micro-object control method using the same, and a method and apparatus for controlling the movement and position of micro- or biochemical micro-objects using alternating current electrowetting.

At present, various studies on the method of controlling the position of the micro-objects are in progress. Representative methods include pipettes and tongs, which are widely used in the past, and include optical methods, pneumatic methods, magnetic methods, and piezoelectric methods.

The method of controlling the position of the micro-object can be divided into a driving method such as thermal, electrostatic, piezoelectric, and pneumatic according to the driving method. The thermal drive method moves an object using a method of using thermal expansion of a material by Joule heat generated by an applied voltage, which has disadvantages in that large driving voltages, energy consumption problems, and application to biotechnology are rather difficult. .

The electrostatic driving method is a method of moving an object by using an electrostatic force between two charges, which has a disadvantage of small driving displacement with respect to a voltage, and when an object is placed, an object cannot be properly placed by a stiction caused by electrostatic power. There is a case. The piezoelectric drive method has advantages of precise drive control and large force, but has a problem that it cannot be used underwater. The pneumatic method does not require a special energy source such as voltage and can be applied to various applications. However, pneumatic control and processing are difficult and a separate packaging process is required for air to enter.

Since the conventional method basically moves an object by direct contact, a problem may arise in the case of a cell, which causes damage by direct contact.

The present invention provides an apparatus and a control method capable of controlling the movement and position of the micro-objects without direct contact with the micro-objects.

The present invention also provides an apparatus and a control method capable of controlling the movement and position of the micro-objects in the underwater environment.

In addition, the present invention provides an optimized range of frequency and voltage that can maximize the vibration width of the bubble for the control of the micro-objects in the device and control method for controlling the movement and position of the micro-objects.

Bubble control apparatus according to the EWOD according to the present invention comprises a first layer comprising an electrode, a dielectric layer and a first hydrophobic layer provided sequentially; A second layer comprising a second hydrophobic layer and a ground layer; An aqueous solution provided between the first hydrophobic layer and the second hydrophobic layer; And a bubble provided in the aqueous solution and forming a micro stream in the surrounding aqueous solution by vibrating upon supplying AC power to the electrode.

The electrodes may also be arranged in at least two.

Furthermore, at least two bubbles may be provided, and the electrodes may be arranged separately with respect to the movement path of the bubbles.

It may also include a control unit for controlling the AC power to be supplied to the electrode opposite to the direction of movement of the bubble around the bubble to move the bubble.

The controller may control the AC power to be sequentially supplied to an electrode adjacent to the opposite side of the bubble moving direction as the bubble moves about the bubble to continuously move the bubble.

The controller may control the AC power to be supplied only to an electrode adjacent to any one of the bubbles in order to change the moving direction of the bubble.

In addition, the electrode may be supplied with an AC voltage having a frequency of 50 to 150 Hz.

In addition, the electrode may be supplied with an alternating voltage of 10 to 150V.

In the method for controlling the micro-objects by the EWOD, the micro-object control apparatus using the bubble stream generated by the EWOD according to the present invention is a micro-object adjacent to the interface of the two micro streams to be formed upon the vibration of two adjacent bubbles A first step of setting to position; And a second step of supplying alternating current power to electrodes positioned opposite to the micro-objects based on the two bubbles.

In addition, the second object may be repeated after the micro-objects and the two bubbles are sequentially moved under the control of the second step.

According to the present invention, the damage caused by contact is avoided by avoiding direct contact with the micro-objects or biochemical micro-objects controlled by moving or controlling the position of the micro-objects or biochemical micro-objects by using the bubbles vibrated by the EWOD. can do.

In addition, according to the present invention by controlling the movement of the bubble by the EWOD has the effect of enabling the position control of the micro-objects, the continuous movement and the change of direction.

In addition, according to the present invention there is an effect that can be used in the underwater environment by controlling the movement and position of the micro-object using a bubble.

1 to 3 is a longitudinal cross-sectional view showing a sequential state of controlling the position and movement of the micro-object through the bubble control device by the EWOD according to an embodiment of the present invention.
4 to 6 are conceptual views schematically showing a sequential state of controlling the position and movement of the micro-objects through the bubble control device by the EWOD according to another embodiment.
7 is a plan view conceptually illustrating a state in which the position and movement of the micro-objects are continuously controlled through the bubble control device by the EWOD according to the embodiment of FIG. 4.
8 and 9 are plan views conceptually illustrating a state in which the movement direction of the micro-objects is changed through the bubble control device by the EWOD according to the embodiment of FIG. 4.
10 is a graph showing the vibration width of the bubble according to the frequency and voltage in the bubble control device by the EWOD according to the present embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the absence of special definitions or references, the terms used in this description are based on the conditions indicated in the drawings. The same reference numerals denote the same members throughout the embodiments. For the sake of convenience, the thicknesses and dimensions of the structures shown in the drawings may be exaggerated, and they do not mean that the dimensions and the proportions of the structures should be actually set.

Electrowetting-on-dieletric (hereinafter referred to as EWOD) refers to a method of changing the contact angle of an insulated / non-insulated fluid drop using electricity. Specifically, a conductive fluid and a non-conductive fluid contact each other on an electrode coated with an insulator. When there is a voltage applied to the electrode and the conductive fluid from the outside to control the surface tension of the conductive fluid to change the contact angle of the conductive fluid and the shape of the interface. EWOD can be used in biomedical applications such as cell manipulation or microsurgery, where precision and accuracy are important.

Bubble control device by EWOD according to the present invention includes an upper layer, a lower layer, an aqueous solution and a bubble. Hereinafter, each component will be described in detail with reference to FIG. 1. 1 is a conceptual longitudinal sectional view showing a bubble control device by an EWOD according to an embodiment of the present invention.

The upper layer 10 includes an electrode 12, a dielectric layer 13 and a hydrophobic layer 14. The electrode 12 functions as an EWOD electrode for controlling the position or movement of the bubble 30 to be described later in an EWOD manner. When power is supplied to any one of the electrodes 12, the hydrophobic layer 14 is modified in a direction in which the portion corresponding to the electrode decreases in hydrophobicity and increases in hydrophilicity.

The formation method of the upper layer 10 is as follows. First, a chromium layer having a thickness of 300 μs using a sputtering phenomenon is formed on the glass wafer 11, and then the EWOD electrode 12 is formed by a wet etching method. Next, a dielectric layer is formed by coating a polyimide having a thickness of 1.6 μm on one surface of the wafer 11 having the electrode 12 by using a spin-coat method. Next, a hydrophobic teflon (eg AF Teflon 1600, Dupont Co.) is coated on the dielectric layer to form a hydrophobic layer 14.

Two or more electrodes 12 may be provided. When the position of the bubble 30 is changed, only one electrode 12 can control the same, but at least two or more electrodes 12 are required to continuously move the bubble 30.

The lower layer 20 includes a wafer 21, a ground layer 22 and a hydrophobic layer 24. The ground layer 22 may be formed by coating indium tin oxide (ITO) on the glass wafer 21. The hydrophobic layer 24 may be formed in the same manner as the hydrophobic layer 14 included in the upper layer 10 described above. That is, the hydrophobic teflon may be coated on the ground layer 22 to form the hydrophobic layer 24.

An aqueous solution (AS) is provided between the hydrophobic layer 14 of the upper layer 10 and the hydrophobic layer 24 of the lower layer 20. Water was used for the aqueous solution (AS) in this example.

Next, the bubble 30 is injected into the aqueous solution AS. At this time, the bubble by air may be used as the bubble 30. When power is supplied to a specific electrode, the hydrophobic layer 14 of the upper layer 14 changes the property of the portion corresponding to the position of the electrode from hydrophobic to hydrophilic, thereby changing the shape of the interface with the droplet. However, in the present embodiment, by using the bubble 30, not the droplet, the behavior of the droplet is reversed. That is, when the property of the hydrophobic layer 14 adjacent to the bubble 30 is changed to hydrophilicity, the bubble 30 is pushed out by pulling the aqueous solution AS. That is, the bubble 30 acts opposite to the existing droplets. On the other hand, the bubble 30 vibrates by repeating contraction and expansion when AC power is supplied to the adjacent electrode 12a. As a result, a micro stream is formed in the aqueous solution around the bubble 30 according to the vibration of the bubble 30. Such micro streams will be described in detail in the relevant sections.

The micro-objects in this embodiment are used in a broad sense including not only simple micro-objects but also biological micro-objects (micro / bio-objects). Fish eggs were used as the micro-objects.

On the other hand, detailed description of the power supply or monitoring device and the like other than each component described above will be omitted.

With reference to Figures 1 to 3 will be described the operation principle of the bubble control device by the EWOD according to this embodiment and a method for controlling the position and movement of the micro-objects thereby. 1 to 3 is a longitudinal cross-sectional view showing a sequential state of controlling the position and movement of the micro-object through the bubble control device by the EWOD according to an embodiment of the present invention.

First, as shown in FIG. 1, the micro object 40 and the bubble 30 are set to be in close proximity for the movement and position control of the micro object 40. Next, as shown in FIG. 2, the AC power is supplied to the electrode 12a adjacent to the opposite direction of the bubble moving direction, that is, the direction D1 in which the micro-object 40 is to be moved, around the bubble 30. do. When an alternating voltage is applied to either electrode 12a, the bubble 30 adjacent to the electrode starts to vibrate. As the bubble 30 vibrates, the micro stream F1 is added to the aqueous solution AS around the bubble 30. Is formed. The micro stream F1 is formed counterclockwise on the right side, and clockwise on the left side of the bubble 30. That is, the micro stream F1 is formed such that the micro-object 40 adjacent to the bottom of the bubble 30 receives a force in a direction away from the bubble 30. Therefore, the micro-objects 40 are moved in the direction D1 away from the bubble 30 by the micro stream F1. On the other hand, the portion A1 of the hydrophobic layer 14 corresponding to the electrode 12a supplied with the alternating voltage gradually changes its property from hydrophobic to hydrophilic. Due to this change in property, the corresponding portion A1 of the hydrophobic layer 14 attracts the aqueous solution AS and pushes the bubbles in a constant direction D1 as shown in FIG. 3.

That is, the controller (not shown) in the present embodiment can control the position and movement of the micro-object 40 by using the bubble 30 by simply controlling the position, order, and the like of the electrode 12 to supply the AC voltage. have.

A method of controlling the position and movement of the micro object using two or more other bubbles will be described with reference to FIGS. 4 to 6. 4 to 6 are conceptual views schematically showing a sequential state of controlling the position and movement of the micro-objects through the bubble control device by the EWOD according to another embodiment.

As shown in FIG. 4, two or more bubbles 30 may be provided. When more than one bubble 30 is provided, it is possible to balance the force compared to controlling the micro-objects 40 by one bubble 30 to control the position and movement of the micro-objects 40 more precisely. Can be.

As shown in FIG. 4, the electrodes 12a and 12b may be provided to correspond to one electrode 12a with respect to two bubbles, and the movement of each bubble 30 to enable independent control of each bubble. It is also possible to have an electrode 12b independent of the path. At this time, the micro-object 40 is set to be adjacent to the interface (L1) of the two bubbles 30, as shown in FIG. The interface L1 means a boundary line where the micro streams by each bubble 30 meet when the two bubbles 30 vibrate to generate the micro streams. By placing the micro-objects 40 adjacent to the interface, the forces exerted by the micro streams generated by the two bubbles 30 can be balanced.

As described above, when an alternating voltage is applied to the electrode 12a positioned opposite from the micro-object 40, the two bubbles 30 vibrate to form a micro stream. At this time, the micro-objects move in a direction D1 away from the two bubbles 30 along the traveling direction of the micro stream.

Then, as described in the previous embodiment, the hydrophobic layer (not shown) whose properties are changed by the electrode 12a to which the alternating voltage is applied moves the two bubbles 30 in the same direction in which the micro-objects 40 move. Let's go.

A method of continuously controlling the position and movement of the micro object will be described with reference to FIG. 7. 7 is a plan view conceptually illustrating a state in which the position and movement of the micro-objects are continuously controlled through the bubble control device by the EWOD according to the embodiment of FIG. 4.

In order to continuously move the micro-objects 40, the movement control method of the micro-objects 40 described above with reference to FIGS. 4 to 6 is continuously performed. That is, the alternating voltage is applied to the electrodes 12b and 12b 'adjacent to the micro-objects 40 among the electrodes adjacent to the two bubbles 30 again while the micro-objects 40 and the two bubbles 30 are moved. Is authorized. As a result, as described above, the micro stream generated by the two bubbles 30 moves the micro-objects 40, and the two bubbles 30 themselves move together. By repeating these steps, the micro-objects 40 can be moved in a predetermined direction while balancing the forces using the two bubbles 30.

A method of changing the moving direction of the micro object will be described with reference to FIGS. 8 and 9. 8 and 9 are plan views conceptually illustrating a state in which the movement direction of the micro-objects is changed through the bubble control device by the EWOD according to the embodiment of FIG. 4.

As described above, when the electrodes corresponding to the bubbles 30 are independently provided, the control of the bubbles 30 may be independently performed. That is, when an alternating voltage is applied to only one electrode 12b as shown in FIG. 8, vibration occurs in the bubble 30 adjacent to the electrode 12b, and the micro-circumference around the bubble 30 is generated. The stream is created. Under the influence of the micro stream, the micro-objects 40 lose their balance of force and change their direction of movement. The bubble 30 then moves in the opposite direction to the electrode 12b as described above.

Referring to Figure 10 looks at the effect of the frequency and voltage of the applied AC voltage on the vibration width of the bubble. 10 is a graph showing the vibration width of the bubble according to the frequency and voltage in the bubble control device by the EWOD according to the present embodiment.

Experiments were conducted under various AC-EWOD operating conditions according to frequency and voltage, and the results are shown in FIG. 10.

As shown in FIG. 10, when the frequency exceeds 100 Hz, for example, when the frequency is excessively increased to about 150 Hz or more, the vibration response speed due to the contraction and expansion of the bubble does not follow, and thus the vibration width is rather reduced. In addition, when the frequency is 50Hz or less, it was found that the bubble's vibration width was reduced due to insufficient shrinkage and expansion of the bubble.

In addition, as shown in FIG. 10, when the voltage was 80 V or less, sufficient vibration width of the bubble could not be obtained. However, due to the characteristic that the voltage varies depending on the thickness of the dielectric, the fluctuation range of the applied voltage is very large. In view of the thickness of the dielectric in this respect, it is preferable to apply a voltage of 10V or more. On the other hand, it can be seen that the vibration width of the bubble increases as the voltage increases, but the vibration width of the bubble according to controlling the microscopic object does not need to increase infinitely, and the energy consumption increases exponentially compared to the increase of the vibration width of the bubble. Voltages above 150V were considered unnecessary.

Although the preferred embodiment of the present invention has been described above, the technical spirit of the present invention is not limited to the above-described preferred embodiment, and the bubble caused by various EWODs within the scope not departing from the technical spirit of the present invention specified in the claims. It can be implemented as a control device and a micro-object control method using the same.

10: upper layer 11, 21: wafer
12, 12a, 12b, 12b 'electrode 13: dielectric layer
14, 24: hydrophobic layer 20: lower layer
22: ground layer 30: bubble
40: micro-object AS: aqueous solution

Claims (10)

A first layer including an electrode, a dielectric layer, and a first hydrophobic layer sequentially provided;
A second layer comprising a second hydrophobic layer and a ground layer;
An aqueous solution provided between the first hydrophobic layer and the second hydrophobic layer; And
Bubbles provided in the aqueous solution, the bubble to form a micro stream in the surrounding aqueous solution by vibrating when supplying alternating current power to the electrode. The method of claim 1,
The electrode is a bubble control device by the EWOD at least two arranged. 3. The method of claim 2,
At least two bubbles are provided,
The electrode is a bubble control device by the EWOD is arranged separately with respect to the movement path of the bubble. The method of claim 3,
And a control unit which controls AC power to be supplied to an electrode opposite to the bubble moving direction about the bubble to move the bubble. 5. The method of claim 4,
The control unit is a bubble control device by the EWOD to control the AC power to be sequentially supplied to the electrode adjacent to the opposite side of the direction in which the bubble moves as the bubble is moved around the bubble in order to continuously move the bubble . 5. The method of claim 4,
The control unit is a bubble control device by the EWOD to control the AC power is supplied only to the electrode adjacent to any one of the bubbles in order to change the movement direction of the bubble. The method of claim 1,
Bubble control device by the EWOD is supplied to the electrode AC voltage of the frequency of 50 to 150 Hz. The method of claim 7, wherein
Bubble control device by the EWOD is supplied with an alternating voltage of 10 to 150V to the electrode. In the method of controlling a micro object by EWOD,
A first step of setting the micro-objects to be adjacent to an interface of two micro streams to be formed upon vibration of two adjacent bubbles; And
And a second step of supplying alternating current power to an electrode positioned opposite to the micro-objects based on the two bubbles. 2. 10. The method of claim 9,
The micro-object control device using a bubble vibrating by the EWOD repeating the second step after the micro-object and the two bubbles are moved in sequence according to the control of the second step.

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