CN103895376B - Method for manufacturing microfluidic dielectrophoresis chips through screen printing technology - Google Patents

Abstract

The invention discloses a method for preparing a microfluidic dielectrophoresis chip by using screen printing technology, comprising the following steps: (1) drawing a microelectrode pattern and a microchannel pattern, and making a microelectrode screen and a microchannel screen; (2) ) Using a micro-electrode screen to print conductive ink on the substrate to prepare a micro-electrode; (3) Using a micro-channel screen to print on the substrate printed with micro-electrodes obtained in step (2) by using the method of target alignment The curable insulating ink is used to make the microchannel; (4) the microchannel is covered with a sealing cover and cured to seal the sealing cover with the microchannel. The invention effectively solves the problems of long production cycle, low efficiency and unsuitability for large-scale industrial production of traditional microfluidic dielectrophoresis chips.

Description

A method for preparing a microfluidic dielectrophoretic chip using screen printing technology

technical field

The invention relates to a microfluidic dielectrophoresis chip, in particular to a method for preparing a microfluidic dielectrophoresis chip by using screen printing technology.

Background technique

Microfluidic chip is a new interdisciplinary field, which integrates basic operation units such as sample preparation, reaction, separation and detection in a few square centimeters with the help of relevant principles and technologies such as micro-electromechanical processing, biology, chemistry and physics. On the chip, a network of microchannels is formed to run through the entire system with controllable fluids to achieve various functions in conventional chemical or biological laboratories. Microfluidic chips have the advantages of low reagent consumption, high detection limit, short analysis time, easy function integration, and convenient portability. They have been widely used in biochemistry, medicine and health, clinical diagnosis, food safety, and environmental monitoring. .

The phenomenon of dielectrophoresis was discovered by Pohl et al. in the 1950s, and it was introduced into the field of chemical analysis and biological research in 1978. But until the 1990s, with the development of microelectronics technology (MEMS), people's research on dielectrophoresis entered a new stage. Micro-nanometer electrodes (or electrode arrays) are produced on the surface of the substrate material by using micro-machining technology, so that the high electric field strength that can be obtained by applying a voltage of thousands of volts can now be achieved with only a few volts or tens of volts, greatly reducing the The adverse effects on the separated substances, especially biomolecules (such as cells, proteins, etc.), are minimized, making dielectrophoresis a powerful tool for driving, separating and concentrating samples. At present, the development trend of dielectrophoresis technology is to integrate it into microfluidic chips to automate and integrate the entire material separation process, or to combine dielectrophoresis technology with other unit technologies to achieve more functions. For example, Petig, Morgan, Green et al. successfully isolated a variety of cells by fabricating metal microelectrodes. The development of microfluidic technology has enabled people to manufacture devices with more reasonable structures to control fluids, and has further deepened the understanding of the interaction between dielectric force and flow force. After 2000, with the deepening of people's understanding of the phenomenon of dielectrophoresis, a variety of new dielectrophoresis technologies have emerged, such as insulator-based DEP, light-induced DEP, and light-induced DEP. ), carbon electrode dielectrophoresis (Carbon DEP), non-contact dielectrophoresis (contactless DEP), etc. Dielectrophoresis not only has important applications in manipulating cells and biomolecules, but also shows great potential in other fields, such as controlling the arrangement of indium arsenide nanowires; making carbon nanotube AFM probes; Separation of metallic single-walled carbon nanotubes from carbon nanotubes; manipulation of nanoparticles to tune optical waveguides, and more.

Currently, dielectrophoretic chips are mostly fabricated using traditional photolithography-based microfabrication methods. This technology has disadvantages such as complex process, high production cost, and long processing cycle, and is not suitable for large-scale industrial production, which severely limits the practical application of dielectrophoretic chips.

Screen printing is a very mature material processing technology widely used in industrial production. It uses the working principle that the mesh of the graphic part of the board can pass through the ink, while the mesh of the non-graphic part is impervious to ink to print on the surface of the base material to produce a thin layer of material with a specific pattern. When printing, pour ink into one end of the screen printing plate, apply a certain amount of pressure on the ink part of the screen printing plate with the scraper, and at the same time, move towards the other end of the screen printing plate. The ink is squeezed by the scraper from the mesh of the graphic part to the substrate during the movement. Since there is a certain gap between the screen printing plate and the substrate, the screen printing plate will generate resilience against the scraper through its own tension during printing, so that there is a moving line between the screen printing plate and the substrate. Contact, the contact line moves with the movement of the scraper, while other parts of the printing plate are separated from the substrate. In this way, the printing accuracy is guaranteed and the substrate is avoided from being dirty. When the scraper scrapes across the entire page and lifts up, the screen printing plate also rises up at the same time, scraping the ink back to the original position lightly, and completing a whole printing process.

Contents of the invention

In order to overcome the shortcomings and deficiencies of the existing dielectrophoretic chip processing and preparation technology, the present invention provides a method for preparing a microfluidic dielectrophoretic chip using screen printing technology, in order to solve the long production cycle and low efficiency of the microfluidic dielectrophoretic chip. problem.

The preparation method of the microfluidic dielectrophoresis chip involved in the present invention is realized by the following technical solutions:

A method for preparing a microfluidic dielectrophoresis chip by screen printing technology, comprising the following steps:

(1) Draw microelectrode patterns and microchannel patterns, and make microelectrode screens and microchannel screens;

(2) Use the microelectrode screen to print conductive ink on the substrate to prepare a single microelectrode or microelectrode array;

(3) Using the micro-channel screen to print curable insulating ink on the substrate printed with micro-electrodes obtained in step (2) by means of target alignment to make micro-channels;

(4) The microchannel is covered with a sealing cover sheet, and the sealing cover sheet is sealed with the microchannel by heat curing or ultraviolet curing.

The conductive ink is at least one of conductive metal paste, conductive semiconductor paste, and conductive carbon paste.

The curable insulating ink is UV curable ink or heat curable ink.

The substrate is a film or bulk material made of PVC, PP, PS, PEI, ABS, PC, PTFE, PE, PCB, PMMA, glass, nylon, or rubber.

The sealing cover is made of glass, PMMA, PDMS, PP, PET, PC, PCB, PVC, nylon, rubber and the like.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The invention solves the disadvantages of high cost, long period and unsuitability for large-scale industrialized production of the microfluidic dielectrophoresis chip produced by the existing microprocessing technology. The present invention adopts screen printing technology, which saves cumbersome processing and manufacturing steps. According to the size of the screen, dozens or even hundreds of micro-electrodes or micro-channels can be obtained in one printing, regardless of production equipment, consumables, and processing costs. Or the requirements for the production environment are far lower than traditional microelectronics technology, and the screen printing method has fast speed and high output, is suitable for large-scale industrial production, and has broad industrialization prospects.

Description of drawings

FIG. 1 is a schematic diagram of the steps of the method for preparing a microfluidic dielectrophoretic chip using screen printing technology according to an embodiment of the present invention.

FIG. 2 is the microelectrode array pattern of Embodiment 1 of the present invention.

Fig. 3 is the microchannel pattern of embodiment 1 of the present invention.

Fig. 4 is a schematic diagram of the microfluidic dielectrophoresis chip prepared in Example 1 of the present invention.

Fig. 5 is an effect diagram before applying an electric signal after injecting a solution containing polystyrene microspheres into the microfluidic dielectrophoresis chip prepared in Example 1.

FIG. 6 is an effect diagram after injecting a solution containing polystyrene microspheres into the microfluidic dielectrophoresis chip prepared in Example 1 and applying an electric signal.

FIG. 7 is an effect diagram after injecting a solution containing yeast cells into the microfluidic dielectrophoresis chip prepared in Example 1 and applying an electrical signal.

FIG. 8 is a microelectrode array pattern of Embodiment 2 of the present invention.

Fig. 9 is an effect diagram before applying an electric signal after injecting a solution containing polystyrene microspheres into the microfluidic dielectrophoresis chip prepared in Example 2.

FIG. 10 is an effect diagram after injecting the solution containing polystyrene microspheres into the microfluidic dielectrophoresis chip prepared in Example 2 and applying an electric signal.

Fig. 11 is an effect diagram after injecting the solution containing yeast cells into the microfluidic dielectrophoresis chip prepared in Example 2 and applying an electric signal.

FIG. 12 is the microelectrode array pattern of Embodiment 3 of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto.

Example 1

As shown in Figure 1, the method for preparing a microfluidic dielectrophoretic chip using screen printing technology in this embodiment includes the following steps:

Draw the microelectrode array pattern (as shown in Figure 2) and the microchannel pattern (as shown in Figure 3), and make a 300-mesh microelectrode screen and microchannel screen; use the microelectrode screen to print conductive carbon ink on the glass surface to prepare the microelectrode array ; Utilize the micro-channel screen, print curable insulating ink on the substrate printed with micro-electrodes obtained in the way of target alignment, and make micro-channels (this step can be repeated many times to obtain micro-channels with different thicknesses) ); cover the polydimethylsiloxane (PDMS) sealing cover slip above the microchannel, and heat-cure to seal the sealing cover slip with the microchannel.

The microfluidic dielectrophoresis chip prepared in this example is shown in FIG. 4 .

A solution containing polystyrene microspheres (PS) was injected into the microfluidic dielectrophoresis chip prepared in this example, and an alternating current signal of a suitable frequency and amplitude was applied. Fig. 5 is an effect diagram before an electric signal is applied, and Fig. 6 is an effect diagram after an electric signal is applied. From Figures 5 to 6, it can be seen that PS microspheres are only subjected to negative dielectric force and concentrated in the middle of the electrode. This shows that the microfluidic dielectrophoresis chip fabricated by the screen printing method can generate dielectric force to separate and purify substances.

The solution containing yeast cells was injected into the microfluidic dielectrophoresis chip prepared in this example, and an alternating current signal of appropriate frequency and amplitude was applied. Figure 7 is the effect diagram after applying the electric signal. Under the conditions of peak voltage of 10V and frequency of 100kHz, positive dielectric power is received. This shows that the microfluidic dielectrophoresis chip fabricated by screen printing can generate dielectric force to separate and purify biomolecules.

Example 2

Draw microelectrode patterns (as shown in Figure 8) and microchannel patterns, and make 400-mesh microelectrode screens and microchannel screens. Use the micro-electrode printing screen to print conductive copper ink on the glass surface to prepare the micro-electrode. After heat curing, use the micro-channel screen to print the UV-curable insulating ink on the glass with the micro-electrode in the way of target alignment. , make the microchannel; cover the polymethyl methacrylate (PMMA) sealing cover sheet above the microchannel, and ultraviolet curing makes the sealing cover sheet and the microchannel seal;

A solution containing polystyrene microspheres (PS) was injected into the microfluidic dielectrophoresis chip prepared in this example, and an alternating current signal of a suitable frequency and amplitude was applied. Fig. 9 is an effect diagram before applying an electric signal, and Fig. 10 is an effect diagram after applying an electric signal. From Figures 9 to 10, it can be seen that the PS microspheres are concentrated in the middle of the electrodes only by the negative dielectric force. This shows that the microfluidic dielectrophoresis chip fabricated by the screen printing method can generate dielectric force to separate and purify substances.

The solution containing yeast cells was injected into the microfluidic dielectrophoresis chip prepared in this example, and an alternating current signal of appropriate frequency and amplitude was applied. Figure 11 is the effect diagram after applying the electric signal. It can be seen from the figure that the yeast cells were found to receive positive dielectric power under the conditions of a peak-to-peak voltage of 10V and a frequency of 100kHz. This shows that the microfluidic dielectrophoresis chip fabricated by screen printing can generate dielectric force to separate and purify biomolecules.

Example 3

Except for adopting the microelectrode pattern shown in FIG. 12 , other features of this embodiment are the same as those of embodiment 1, and the test results are similar to those of embodiment 1, which will not be repeated here.

In addition to glass, the substrate in the above embodiments can also be a film or block material made of PVC, PP, PS, PEI, ABS, PC, PTFE, PE, PCB, PMMA, glass, nylon or rubber; The conductive ink can also use conductive semiconductor paste, or a mixture of two or more of conductive metal paste, conductive semiconductor paste, and conductive carbon paste; the sealing cover can also be made of glass PP, PET, PC, PCB, PVC, Prepared from nylon or rubber.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the embodiment, and any other changes, modifications, substitutions and combinations made without departing from the spirit and principle of the present invention , simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims (3)

1. A method utilizing screen printing technology to prepare microfluidic dielectrophoresis chip, is characterized in that, comprises the following steps: (1) Draw microelectrode patterns and microchannel patterns, and make microelectrode screens and microchannel screens; (2) Utilize the microelectrode screen to print conductive ink on the substrate to prepare a single microelectrode or microelectrode array; the conductive ink is at least one of conductive metal paste, conductive semiconductor paste, and conductive carbon paste ; (3) Utilize the microchannel screen plate to print curable insulating ink on the substrate printed with microelectrodes obtained in step (2) by means of target alignment to make microchannels; the curable insulating ink is ultraviolet curing ink or heat curable ink; (4) Cover the sealing cover sheet above the microchannel, and make the sealing cover sheet and the microchannel seal by heat curing or ultraviolet curing; Step (3) can be repeated many times to obtain microchannels with different thicknesses; The microfluidic dielectrophoresis chip prepared by screen printing technology separates and purifies substances by generating dielectric force. 2. utilize screen printing technology to prepare the method for microfluidic dielectrophoresis chip according to claim 1, it is characterized in that, described substrate is PVC, PP, PS, PEI, ABS, PC, PTFE, PE, PCB , PMMA, glass, nylon or rubber made of film or block material. 3. utilize screen printing technology to prepare the method for microfluidic dielectrophoresis chip according to claim 1, it is characterized in that, described sealing cover sheet is made of glass, PMMA, PDMS, PP, PET, PC, PCB, PVC , nylon or rubber.