A method for manufacturing a flexible microfluidic chip with metal electrodes

Abstract

The present invention discloses a method for fabricating a flexible microfluidic chip with metal electrodes, belonging to the field of microfluidic chip technology. First, direct-write nanofibers are superimposed on a rotating receiving substrate to prepare a linear micro-ridge structure; then, a polymer film with micro-channels is fabricated using the micro-ridge structure as a template; then, metal is deposited on the surface of the polymer film using a thin film deposition method; subsequently, a patterned metal electrode is fabricated on a flexible substrate containing micro-channels by direct-writing photoresist as a protective layer on a translational receiving substrate, combined with a wet etching process; finally, a flexible microfluidic chip is prepared by encapsulation. The fabrication method of the present invention is not limited by substrate material, flatness, or hardness, and can also perform patterned processing of metal electrodes on a flexible substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of microfluidic chips, and in particular to a method for manufacturing a flexible microfluidic chip with metal electrodes. Background Art

[0002] Microfluidic chips have attracted much attention in fields such as biology and chemistry due to their miniaturization and integration. In particular, microfluidic chips with metal electrodes have been widely used in capillary electrophoresis, electrochemical trace detection, biomedical engineering, and flexible electronics.

[0003] Traditional microfluidic chip processing methods such as photolithography and soft lithography have high requirements for the flatness and hardness of the substrate. At the same time, the complex process steps limit the flexible manufacturing of microfluidic chips. Injection molding and hot pressing molding technologies require molds to be prepared in advance, which increases processing costs and has the problem of difficulty in filling and molding materials at the microscale. Microscale milling technology has low processing efficiency and is time-consuming. Although laser direct writing technology uses maskless direct writing to prepare microfluidic chips, its time-consuming preparation process limits processing efficiency. Summary of the Invention

[0004] In response to the above-mentioned shortcomings of the existing technology, the present invention provides a method for manufacturing a flexible microfluidic chip with metal electrodes. This method is not limited by the substrate material, flatness, and hardness, and can perform patterning of metal electrodes on a flexible substrate.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for manufacturing a flexible microfluidic chip with metal electrodes, the method comprising the following steps:

[0007] (1) Fabrication of linear microridge structures on flexible substrates;

[0008] (2) Fabrication of polymer films with microgrooves using microridge structures as templates;

[0009] (3) depositing a metal film on the surface of the polymer film;

[0010] (4) The fabrication of patterned metal electrodes on a flexible substrate containing micro-grooves is achieved by directly writing a photoresist as a protective layer on a translation receiving substrate and combining it with a wet etching process;

[0011] (5) Prepare flexible microfluidic chips by packaging.

[0012] In step (1), the process of preparing the linear micro-ridge structure is as follows: a flexible substrate is coated on a roller as a rotating receiving substrate, and the printing material is deposited in an orderly manner on the receiving substrate using an electrospray printing system to form a smooth linear micro-ridge structure; during the deposition process, the distance between the needle tip and the substrate is adjustable, and the rotation speed, printing voltage, printing time, printing material and printing substrate are all adjustable, and the width and height of the micro-ridges can be controlled according to different usage requirements; an arrayed one-dimensional micro-ridge structure or a two-dimensional micro-ridge structure can be produced.

[0013] The flexible substrate is polyethylene terephthalate (PET), polyimide (PI), aluminum foil or tin foil; the printing material is polyvinyl alcohol (PVA) or polymethyl methacrylate (PMMA).

[0014] In step (2), the manufacturing process of the polymer film with micro-channels is as follows: a polymer precursor solution is poured onto the micro-ridge structure, and after solidification, a mold is formed to obtain a polymer film with micro-channels.

[0015] In step (2), the polymer is polydimethylsiloxane (PDMS) or Ecoflex.

[0016] In step (3), a metal film is deposited on the surface of the polymer film containing micro-channels by using a thin film deposition method.

[0017] In step (4), the polymer film with the metal film is placed on a horizontal motion platform as a translation receiving substrate, and the photoresist is patterned and printed using an electrospray printing system. Then, a patterned metal electrode is obtained by wet etching, and the photoresist on the surface of the patterned metal electrode is removed. The metal electrode can be patterned with different structures according to usage requirements.

[0018] In step (5), the microchannels are packaged to obtain a flexible microfluidic chip with patterned metal electrodes.

[0019] The flexible polymer film can be replaced with different materials according to different needs, and the metal electrode can be replaced with different materials according to different needs.

[0020] The advantages and beneficial effects of the present invention are as follows:

[0021] The manufacturing method of the present invention is not limited by substrate material, flatness, and hardness, and can also perform patterning processing of metal electrodes on a flexible substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of fabricating micro-ridge structures on a flexible substrate.

[0023] Figure 2 Schematic diagram of the fabrication of a polymer film with microchannels.

[0024] Figure 3 Schematic diagram of depositing metal film on the surface of a polymer film containing micro-grooves.

[0025] Figure 4 Schematic diagram of photoresist patterning using an electrospray printing system.

[0026] Figure 5 Schematic diagram of metal electrode patterning.

[0027] Figure 6 Schematic diagram of removing photoresist from the surface of metal electrode.

[0028] Figure 7 Schematic diagram of a flexible microfluidic chip with metal electrodes after packaging.

[0029] Figure 8 This is a finished flexible microfluidic chip prepared by the present invention.

[0030] In the figure: 1 flexible substrate, 2 printing material; 3 flexible polymer; 4 metal film; 5 photoresist. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below in conjunction with the technical solutions and drawings.

[0032] The present invention provides a method for fabricating a flexible microfluidic chip with metal electrodes. First, direct-write nanofibers are superimposed on a rotating receiving substrate to prepare a linear micro-ridge structure. Next, a polymer film with micro-channels is fabricated using the micro-ridge structure as a template. Then, metal is deposited on the surface of the polymer film using a thin film deposition method. Subsequently, a photoresist is directly written as a protective layer on a translating receiving substrate, combined with a wet etching process, to fabricate patterned metal electrodes on a flexible substrate containing micro-channels. Finally, the flexible microfluidic chip is prepared by encapsulation. Specifically, the method includes the following steps:

[0033] 1) A flexible substrate is wrapped around a roller as a rotating receiving substrate, and a printing material is deposited onto the receiving substrate in an orderly manner using an electrospray printing system to form a smooth linear micro-ridge structure. The flexible substrate includes polyethylene terephthalate (PET), polyimide (PI), aluminum foil, or tin foil; and the printing material includes polyvinyl alcohol (PVA) or polymethyl methacrylate (PMMA).

[0034] 2) Casting a polymer precursor solution onto the micro-ridge structure and performing a mold remolding after solidification to obtain a polymer film with micro-grooves. The polymer includes polydimethylsiloxane (PDMS) and Ecoflex.

[0035] 3) A metal film is deposited on the surface of a polymer film containing micro-grooves using a thin film deposition method.

[0036] 4) The polymer film with the metal film is placed on a horizontal motion platform as a translation receiving substrate, and a photoresist pattern is printed using an electrospray printing system.

[0037] 5) Obtain patterned metal electrodes by wet etching.

[0038] 6) Removing the photoresist on the surface of the patterned metal electrode.

[0039] 7) After encapsulating the microchannels, a flexible microfluidic chip with patterned metal electrodes is obtained.

[0040] Example 1:

[0041] This embodiment is a method for manufacturing a flexible microfluidic chip with metal electrodes. Its structure and manufacturing process are as follows: Figure 1-7 As shown in the figure, a flexible substrate 1 is first coated on a roller as a rotating receiving substrate. A printing material 2 is deposited onto the receiving substrate in an orderly manner using an electrospray printing system to form a smooth micro-ridge structure. A polymer precursor solution is then poured onto the micro-ridge structure and, after solidification, a mold is formed to form a polymer film 3 with micro-channels. A metal film 4 is then deposited on the surface of the polymer film 3 with micro-channels using a thin film deposition method. The polymer film 3 with the metal film 4 is then placed on a horizontal motion platform as a translational receiving substrate and patterned with a photoresist 5 using an electrospray printing system. Patterned metal electrodes are then formed by wet etching. The photoresist 5 on the surface of the patterned metal electrodes is then removed. Finally, the micro-channels are encapsulated to obtain a flexible microfluidic chip with patterned metal electrodes.

[0042] The above examples merely express the embodiments of the present invention, but they should not be understood as limiting the patent of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, which all fall within the scope of protection of the present invention.

[0043] Example 2:

[0044] Tin foil was wrapped on a roller as the receiving substrate 1. At a temperature of 30°C and a humidity of 50% RH, the printing material 2, polyvinyl alcohol water-soluble, was deposited in an orderly manner on the receiving substrate 1 using an electrospray printing system. The vertical distance between the printing needle tip and the roller was 3 mm, the liquid feed rate of the printing material 2 was 0.6 ml / h, the potential difference was 2 kV, the roller speed was 400 rpm, and the in-situ printing was performed for 20 seconds to complete the preparation of the smooth micro-ridge structure.

[0045] Polydimethylsiloxane was used as the flexible polymer film 3. The polydimethylsiloxane main agent and the curing agent were mixed in a mass ratio of 10:1 to prepare a polymer precursor, which was poured onto the micro-ridge structure and heated at 80°C for 2 hours to cure to prepare a flexible polymer film 3 with micro-grooves.

[0046] A gold film 4 is deposited on the surface of the flexible polymer 3 with micro-grooves by magnetron sputtering. The power of the magnetron sputtering instrument is 80W, the sputtering time is 2.5 minutes, and a 50nm thick gold film 4 is sputtered as a conductive layer.

[0047] AZ1505 photoresist 5 was patterned masklessly using an electrojet printing system. The print tip was 100 μm above the substrate, the receiving substrate was moved at a speed of 200 μm / s, and the system operated at a DC voltage of 300 V, an AC voltage of 50 V, a frequency of 1000 Hz, and a duty cycle of 75%. The photoresist 5 was cured by heating at 60°C for 30 minutes.

[0048] Gold etching solution was dropped onto the flexible polymer film 3 containing the photoresist 5 for 30 seconds to etch the metal film 4 not protected by the photoresist 5, and then washed with deionized water for 10 seconds; heated at 60°C for 20 minutes to evaporate the surface water, thereby obtaining a patterned metal electrode.

[0049] The flexible polymer film 3 was exposed to UV light for 30 minutes, then immersed in a developer for 5 minutes to remove the photoresist 5 on the surface of the patterned metal electrode. The film was then washed with anhydrous ethanol and deionized water for 1 minute each to remove residual reagents, and heated at 60°C for 20 minutes to evaporate the surface moisture.

[0050] The polydimethylsiloxane film and the flexible polymer film with microchannels 3 were treated with oxygen plasma for 5 minutes, and the treated polydimethylsiloxane film was bonded to the flexible polymer film with microchannels 3 to complete the preparation of the flexible microfluidic chip with metal electrodes. Figure 8 shown.

Claims

1. A method for fabricating a flexible microfluidic chip with metal electrodes, characterized in that: The method comprises the following steps: (1) Fabrication of linear microridge structures on flexible substrates; The flexible substrate is wrapped on a roller as a rotating receiving substrate, and the printing material is deposited onto the receiving substrate in an orderly manner using an electrospray printing system to form a smooth linear micro-ridge structure; During the deposition process, the distance between the needle tip and the substrate is adjustable, as are the rotation speed, printing voltage, printing time, printing material, and printing substrate. The width and height of the micro-ridges can be controlled according to different usage requirements; arrayed one-dimensional or two-dimensional micro-ridge structures can be produced. (2) Fabrication of polymer films with microgrooves using microridge structures as templates; (3) depositing a metal film on the surface of the polymer film; (4) The fabrication of patterned metal electrodes on a flexible substrate containing micro-grooves is achieved by directly writing a photoresist as a protective layer on a translation receiving substrate and combining it with a wet etching process; (5) Prepare flexible microfluidic chips by packaging.

2. The method for fabricating a flexible microfluidic chip with metal electrodes according to claim 1, wherein: The flexible substrate is polyethylene terephthalate (PET), polyimide (PI), aluminum foil or tin foil; the printing material is polyvinyl alcohol (PVA) or polymethyl methacrylate (PMMA).

3. The method for fabricating a flexible microfluidic chip with metal electrodes according to claim 1, wherein: In step (2), the manufacturing process of the polymer film with micro-channels is as follows: a polymer precursor solution is poured onto the micro-ridge structure, and after solidification, a mold is formed to obtain a polymer film with micro-channels.

4. The method for fabricating a flexible microfluidic chip with metal electrodes according to claim 3, wherein: In step (2), the polymer is polydimethylsiloxane (PDMS) or Ecoflex.

5. The method for manufacturing a flexible microfluidic chip with metal electrodes according to claim 1, wherein: In step (3), a metal film is deposited on the surface of the polymer film containing micro-channels by using a thin film deposition method.

6. The method for fabricating a flexible microfluidic chip with metal electrodes according to claim 1, wherein: In step (4), the polymer film with the metal film is placed on a horizontal motion platform as a translation receiving substrate, and the photoresist is patterned and printed using an electrospray printing system. Then, a patterned metal electrode is obtained by wet etching, and the photoresist on the surface of the patterned metal electrode is removed. The metal electrode can be patterned with different structures according to usage requirements.

7. The method for manufacturing a flexible microfluidic chip with metal electrodes according to claim 1, characterized in that: In step (5), the microchannels are packaged to obtain a flexible microfluidic chip with patterned metal electrodes.

8. The method for manufacturing a flexible microfluidic chip with metal electrodes according to claim 1, wherein: The flexible polymer film can be replaced with different materials according to different needs, and the metal electrode can be replaced with different materials according to different needs.

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