CN109307102B - Micro valve device for micro-fluidic chip and preparation method and application thereof - Google Patents

Abstract

The invention discloses a micro-valve device for a micro-fluidic chip and a preparation method and application thereof. The micro-valve structure is easy to manufacture, and the manufacturing difficulty of the valve structure in the micro-fluidic chip is greatly reduced; meanwhile, the structure can accurately change the opening and closing states of the valve in real time by adjusting the input signal, so that the movement of the fluid in the microfluidic chip is accurately controlled.

Description

A microvalve device for a microfluidic chip and its preparation method and application

technical field

The invention relates to a microvalve device for a microfluidic chip, a preparation method and application thereof, and belongs to the technical field of microfluidic chips.

Background technique

The concept of microfluidic chip was born at the end of the 20th century, through the design and manufacture of miniaturized chip devices to achieve the purpose of automation and integration to complete experimental operations. Microfluidic chip technology uses micromachining technology to process a certain pattern on the surface of the material. After packaging and other steps, it becomes a certain flow channel structure to control the flow of fluid in the chip, so as to complete certain reactions, and finally replace the conventional Purpose of the experimental platform. Microfluidic chips have been widely used in many fields such as drug screening, cell culture, and immunoassays.

The control of the flow path and whether to flow of the fluid in the microfluidic chip can be realized by the valve structure. In recent years, with the development of microfluidic technology, various microvalve structures have appeared. In the existing micro-valve structure, components that can translate or rotate are added to the microfluidic chip, and the inside of the component is perforated to connect the upstream and downstream of the flow channel. The channels are aligned or staggered to achieve the effect of valve structure opening and closing, such as ball valves and solenoid valves.

However, this valve structure has drawbacks. First, the structure is difficult to assemble due to the need to add movable components to the smaller microfluidic chip; secondly, since the flow channel wall is composed of multiple parts, errors in the assembly process can easily cause the flow of the microfluidic chip In addition, the structure needs to customize components of different sizes according to different microfluidic chip sizes, which is difficult to mass-produce. These defects make it difficult for this microvalve structure to be widely used in microfluidic chips. Other microvalves use external force to cause the deformation of the microchannel to control the opening and closing of the channel. For example, by controlling the pressure of the gas in the airway, the filling of the airway at high pressure is used to squeeze the liquid channel perpendicular to it, so that the channel is closed. , at low pressure the airway shriveles and re-opens the fluid flow path. This kind of microvalve has the advantages of easy assembly, no change to the original flow channel structure, and easy acceptance of external signal control. The existing deformation-based microvalve realizes the pressing and restoring of the flow channel by controlling the application and removal of external force on the outer wall of the flow channel. The flow channel is a single flow channel, and the external force required for its deformation is large, and Often there are situations such as lax pressing.

SUMMARY OF THE INVENTION

Purpose of the Invention: The purpose of the present invention is to provide a microvalve device for a microfluidic chip and a preparation method and application thereof, the microvalve structure is easy to assemble, does not change the original flow channel structure, and the moving parts do not directly contact the fluid .

Technical scheme: in order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme:

A microvalve device for a microfluidic chip, comprising a cover sheet, an elastic material layer and a deformable device layer, the elastic material layer is located between the cover sheet and the deformable device layer, and the middle of the elastic material layer and the cover sheet is provided with Independent liquid passage and cavity, the cavities are located on both sides of the liquid passage, and the elastic material layer can be elastically deformed under the extrusion or pulling of the deformable device layer, thereby controlling the closing and closing of the liquid passage. on.

In addition, it also includes two circular holes arranged on the surface of the cover sheet, which are respectively connected with the openings at both ends of the liquid passage.

The deformable device layer is a piezoelectric film, which is connected to the electrical signal generating device.

The preparation method of the microvalve device for the microfluidic chip comprises the following steps:

(1) Using PDMS material (polydimethylsiloxane), mix the prepolymer with the curing agent, pour it into the prepared mold, degas the PDMS, and then heat it to cure it to form a long concave The structure of grooves and shorter grooves on both sides;

(2) bonding the patterned side of the PDMS with the cover sheet to form a liquid-passing flow channel that can perform liquid-passing operation and a closed cavity on both sides of the flow channel;

(3) Using the adhesive bonding of PDMS itself, a deformable device layer with a size that can cover two cavity regions is covered on the lower surface of the PDMS chip, that is, it is obtained.

In step (2), before the cover sheet is bonded to the PDMS, two circular holes are carved on the cover sheet, and the relative positions of the centers of the two circular holes correspond to the two end points of the linear pattern on the PDMS surface.

Finally, the invention also provides the application of the microvalve device of the microfluidic chip to detect the efficiency of polymerase chain reaction.

The main structure of the microvalve of the present invention consists of a soft material containing three parallel cavities and a deformable device. The microfluidic channel is prepared by using an elastic soft material. The soft material contains three parallel cavities in total, of which the central cavity is used as a liquid flow channel, and the cavities on both sides do not pass liquid, which is the possible deformation of the flow channel. Provide room for deformation. The cavities on both sides may be closed cavities or not. The outer surface of the above-mentioned soft material is flat and smooth, and is fitted with a flat deformable device, and the projected area of the device on the cavity surface overlaps with the liquid passage. The above-mentioned deformable device can be deformed in a controlled manner, and can exert a deformation effect on the cavity on the outside of the soft material. The cavity provides room for deformation, reducing the driving force required for runner wall fit. By controlling the deformation of the deformable device, the opening and closing states of the microvalve can be changed. After the deformation occurs, the bonding state of the two walls of the cavity flow channel changes, which can be changed from bonding to separation, and can also be changed from separation to bonding. When the two walls of the flow channel are attached, the flow channel is closed and the fluid cannot pass through. When the two walls of the flow channel are separated, the flow channel is open and the fluid flows normally. By controlling the deformable device to change whether the two walls of the intermediate cavity fit together, it can be that when the deformable device is deformed, the two walls of the intermediate cavity are attached, and when the deformation is removed, the two walls of the intermediate cavity are separated, or when the deformable device is deformed The two walls of the middle cavity are separated, and the two walls of the middle cavity fit together when the deformation is removed.

The micro-valve of the invention is easy to assemble, does not change the original flow channel structure, and has a valve structure that the movable parts do not directly contact the fluid. At the same time, the external force required for the deformation of the microvalve is small, which is suitable for electric drive devices such as piezoelectric membranes, and is easy to accept external signal control. The opening and closing states of the valve can be accurately changed in real time by adjusting the signal input, thereby accurately controlling the microflow. fluid movement in the control chip. Moreover, the microvalve is tighter than the traditional deformable microvalve when closed.

Beneficial effects: Compared with the prior art, the micro-valve device of the present invention does not need a complicated assembly process, and is easy to produce in batches. When preparing the flow channel, a cavity is left on the left and right of the flow channel where the valve structure needs to be set, and the deformable device is covered on the outside of the flow channel. It is easy to reduce the driving force change range required for changing the closed state of the flow channel, expand the selection surface of deformable devices, and enable some easy-to-control limited deformation devices to be used in the assembly of microvalves, and the design of the flow channels on both sides makes When the liquid passage is closed, it is more complete, and it is not easy to cause incomplete closure. At the same time, the structure can accurately change the opening and closing state of the valve in real time by adjusting the input signal, so as to precisely control the fluid movement in the microfluidic chip.

Description of drawings

Fig. 1: sectional schematic diagram of the microvalve device of the present invention (open state);

Fig. 2: sectional schematic diagram of the microvalve device of the present invention (closed state);

Figure 3: a schematic diagram of the composition of the microvalve device of the present invention;

Figure 4: Schematic diagram of the composition of the microvalve device of the present invention (top view).

Detailed ways

The method of the present invention will be further described below in conjunction with specific embodiments.

Example 1:

A microvalve device for a microfluidic chip, as shown in Figures 1, 2, 3 and 4, comprises a cover sheet 1, an elastic material layer 2 and a deformable device layer 5, and the elastic material layer 2 is located between the cover sheet 1 and the deformable device layer 5. In the middle of the deformable device layer 5, and between the elastic material layer 2 and the cover sheet 1, there is an independent liquid passage 3 and a cavity 4, the cavity 4 is located on both sides of the liquid passage 3, and the elastic material layer 2 can The elastic deformation is carried out under the pressing or pulling of the deformable device layer 5 , so as to control the closing and opening of the liquid passage 3 .

In addition, it also includes two circular holes 6 arranged on the surface of the cover sheet 1 , which are respectively connected with the openings at both ends of the liquid passage 3 .

The deformable device layer 5 is a piezoelectric film 7 which is connected to an electrical signal generating device 8 .

Example 2:

As shown in Figure 3, using PDMS material, mix the prepolymer and the curing agent in a ratio of 10:1, and pour it into the prepared mold. Two rectangular protrusions are symmetrically distributed, and the heights of the protrusions may be the same or different. The PDMS was degassed and then heated to 85°C to cure it, forming a structure containing a long groove with shorter grooves on both sides. Two circular holes 6 are engraved on a piece of glass by a laser engraving machine, and the relative positions of the centers of the two circular holes 6 correspond to the two end points of the above-mentioned PDMS surface linear pattern.

Align the circular hole on the glass sheet with the two ends of the straight line on the PDMS, and the patterned side of the PDMS is bonded to the glass sheet to form a straight channel (liquid flow channel 3) and two flow channels that can perform liquid-passing operations. side closed cavity 4. Cover the surface of the PDMS chip with a piece of deformable device 5 (a thin piezoelectric device, namely the piezoelectric film 7) with a size that can cover the two cavity regions, and the piezoelectric The membrane 7 is connected to an electrical signal generating device 8 , which can adjust the voltage applied to the piezoelectric membrane 7 .

This valve structure is normally open. When the micro-valve needs to be opened, no voltage is applied to the two poles of the piezoelectric film 7. At this time, the piezoelectric film 7 is not deformed, the flow channel 3 is unblocked, and the fluid flows normally, as shown in FIG. 1 . When the micro-valve needs to be closed, the electrical signal generator 8 is adjusted so that there is a potential difference between the two poles of the piezoelectric film. At this time, the piezoelectric film 7 bulges toward the direction of the flow channel 3, squeezes the flow channel 3 and makes it closed, so as to hinder the flow of the fluid. . As shown in FIG. 2 , the region of the flow channel 3 corresponding to the piezoelectric film 7 is squeezed and collapsed and is in a closed state, and the cavities 4 on both sides of the flow channel 3 are partially collapsed due to the deformation of the piezoelectric film 7; The channel 3 and the deformable device 5 (piezoelectric film 7 ) deform to provide an active space.

Example 3:

According to the method of Example 1, the deformable device 5 (piezoelectric film 7 ) is bonded to the surface of PDMS with glue, and the piezoelectric film 7 is adjusted to bend in the direction of the liquid passage 3 in advance to form a normally closed valve structure. When no voltage is applied to the piezoelectric film 7, the piezoelectric film 7 squeezes the flow channel, the upper and lower surfaces of the liquid-passing flow channel 3 are in contact with each other, and the fluid cannot pass through. When the electrical signal generator 8 is used to apply the opposite potential difference to the piezoelectric film 7, the center of the piezoelectric film 7 is deformed away from the flow channel, so that the upper and lower surfaces of the flow channel 3 are separated, and the fluid can flow normally at this time.

Example 4:

This construct was used to test polymerase chain reaction (PCR) efficiency according to the method of Example 2. The hole at one end of the chip is used as the injection hole, and a temperature control device is placed under the injection hole. The other well serves as a detection well, and PicoGreen dye is pre-immobilized on the bottom of the well. The configured PCR system was dropped into the injection hole, and the temperature was adjusted by a temperature control device, so that the dropped solution was subjected to PCR reaction. After the reaction, the piezoelectric film 7 is energized, and the piezoelectric film 7 will deform in the direction away from the liquid passage 3 after the electricity is applied, so that the micro-valve is opened. The liquid flows to the detection hole by capillary action, and the dye in the detection hole will combine with the DNA in the liquid and emit fluorescence. The concentration of DNA in the solution after the reaction can be quantitatively obtained by detecting the fluorescence intensity with an instrument.

Claims (5)

1. A microvalve device for a microfluidic chip, characterized in that it comprises a cover sheet (1), an elastic material layer (2) and a deformable device layer (5), and the elastic material layer (2) is located in the cover sheet Between (1) and the deformable device layer (5), and between the elastic material layer (2) and the cover sheet (1), there is an independent liquid passage (3) and a cavity (4), and the cavity (4) ) are located on both sides of the liquid passage (3), three parallel, wherein the liquid passage (3) is a linear liquid passage, the cavities (4) on both sides are not liquid, and the elastic material layer (2) The elastic deformation can be carried out under the extrusion or pulling of the deformable device layer (5), so as to control the closing and opening of the liquid passage (3); the two circular holes (6) on the surface of the cover sheet (1), which They are respectively connected with the openings at both ends of the liquid passage (3). 2. The microvalve device for a microfluidic chip according to claim 1, wherein the deformable device layer (5) is a piezoelectric film (7), which is connected to an electrical signal generating device (8) connected. 3. the preparation method of the microvalve device for microfluidic chip according to claim 1, is characterized in that, comprises the following steps: (1) Using the PDMS material, mix the prepolymer with the curing agent, pour it into the prepared mold, degas the PDMS, and then heat it to cure it to form a long groove and two short grooves on both sides. structure; (2) bonding the patterned side of the PDMS with the cover sheet to form a liquid-passing flow channel that can perform liquid-passing operation and a closed cavity on both sides of the flow channel; (3) Using the adhesive bonding of PDMS itself, a deformable device layer with a size that can cover two cavity regions is covered on the lower surface of the PDMS chip, that is, it is obtained. 4. preparation method according to claim 3, is characterized in that, before cover sheet and PDMS are bonded in step (2), first engrave two circular holes on the cover sheet, and the relative position of the center of the two circular holes is linear with the PDMS surface The two endpoints of the pattern correspond. 5. The application of the microvalve device of the microfluidic chip according to any one of claims 1 to 2 to detect the efficiency of polymerase chain reaction.

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