Light-operated three-dimensional transfer arm for transferring liquid drops

Abstract

The invention relates to liquid drop transfer equipment, in particular to a light-operated three-dimensional transfer arm for transferring liquid drops, which comprises a light response double-layer heterogeneous film, a three-axis translation device and a light source, the photoresponse double-layer heterogeneous film is arranged at the tail end of the three-axis translation device and is controlled by the three-axis translation device to move; the light source is arranged above the light response double-layer heterogeneous film and moves along with the light response double-layer heterogeneous film; the photoresponse double-layer heterogeneous film is formed by overlapping a photoresponse film and a polymer film; the photoresponse film deforms when irradiated by a light source, and a microarray structure used for adhering liquid drops is arranged on the surface of the polymer film. Compared with the prior art, the defect that in the prior art, high-viscosity biological liquid cannot be adhered and transported due to wettability difference achieved only by means of a micro / nano structure is overcome, and effective grabbing and accurate transferring of bio-based liquid drops are achieved.

Description

Technical Field

[0001] The invention relates to a droplet transport device, in particular to a transport arm for light-controlled three-dimensional transport of droplets. Background Art

[0002] The precise manipulation of micro-droplets can significantly reduce reagent consumption and has broad application prospects in the fields of microfluidics, biochemical analysis, micro-reaction systems and trace analysis. Using responsive materials to make "smart" solid surfaces can provide asymmetric surface wetting gradients through different external stimuli such as magnetic fields, electric fields, light, pH, temperature, etc., counteract contact angle hysteresis, lead to different Laplace pressures and drive the directional movement of droplets on the same surface.

[0003] Based on the transportation of solid objects by grippers, a variety of "droplet grippers" have been developed in the prior art to achieve three-dimensional (3D) manipulation and transportation of droplets, and to transport droplets between different surfaces. The process of achieving three-dimensional spatial manipulation of droplets includes three main actions, namely: grabbing, transporting, and releasing, and further the cycle of the three actions can achieve different reactions and analysis processes.

[0004] However, due to the limitations of interface structure design and manipulation principles, there are still huge challenges in achieving quantitative capture and release of all types of bio-based micro-droplet samples. In existing research, the interface structure design of corresponding materials to achieve selective capture of droplets of different types and volumes is one of the effective means to solve the above problems, but how to achieve selective capture of multiple types of droplets is still a key issue to be solved.

[0005] The current technology of using smart materials to capture micro-droplets has problems such as limited types of manipulable droplets and inability to achieve precise and controllable release of droplets. In addition, the wettability differences that can be achieved by designing micro / nano structures are still limited and insufficient for transporting high-viscosity biological fluids such as serum and blood. Therefore, it is necessary to develop a new type of droplet gripper to transport bio-based droplets. Summary of the invention

[0006] The purpose of the present invention is to provide a transport arm for light-controlled three-dimensional transport of droplets in order to solve at least one of the above problems, so as to overcome the defect in the prior art that only the wettability difference achieved by micro / nanostructure cannot adhere to and transport high-viscosity biological liquids, thereby realizing the effective grasping and precise transport of bio-based droplets.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A transport arm for light-controlled three-dimensional transport droplets, comprising a light-responsive double-layer heterogeneous membrane, a three-axis translation device and a light source;

[0009] The photoresponsive double-layer heterogeneous film is arranged at the end of the three-axis translation device, and the movement is controlled by the three-axis translation device;

[0010] The light source is arranged above the light-responsive double-layer heterogeneous film and moves along with the light-responsive double-layer heterogeneous film;

[0011] The photoresponsive double-layer heterogeneous film is formed by stacking a photoresponsive film and a polymer film; the photoresponsive film is deformed when irradiated by a light source, and a microarray structure for adhering droplets is provided on the surface of the polymer film.

[0012] Preferably, the material of the photoresponsive film includes liquid crystal polymer, photoresponsive gel film, photoresponsive polyimide and polyurethane; the photoresponsive time of the photoresponsive film does not exceed 1 s, and the deformation amount is not less than 15 μm.

[0013] Preferably, the photoresponsive film has a thickness of 10-50 μm, and a length and width of 5-50 mm; the lowest response temperature of the photoresponsive film is not higher than 20° C., and the highest response temperature is not lower than 100° C.

[0014] Preferably, the material of the polymer film includes silicone film, hydrogel film, polyurethane and polyimide film; the microarray structure is made by one or more of template method, photolithography method, hot pressing method and 3D printing method.

[0015] Preferably, the polymer film has a thickness of 10-50 μm, and a length and width of 5-50 mm.

[0016] The photoresponsive film and the polymer film are consistent in size and shape, so they can be integrated and move (deform) synchronously.

[0017] Preferably, the light source is a single point light source, a line light source or an array integrated light source, and the light beam emitted by the light source is one or more of an ultraviolet light source, a visible light source and a near-infrared light source.

[0018] Preferably, the light source is arranged 5-15 cm above the photoresponsive double-layer heterogeneous membrane.

[0019] Preferably, the three-axis translation device is a three-axis slide or a CNC machine tool, having a repeat positioning accuracy within 10 μm, a moving speed range of 10-100 mm / min, and a controllable moving range of not less than 80 mm×80 mm.

[0020] Preferably, the photoresponsive film is bonded and fixed to the polymer film, and the photoresponsive double-layer heterogeneous film is bonded and fixed to the three-axis translation device.

[0021] Preferably, the light-responsive double-layer heterogeneous film is bonded to the end of the three-axis translation device through a glass sheet.

[0022] The working principle of the present invention is:

[0023] The photoresponsive bilayer heterogeneous membrane is driven to translate to about 1-10 mm above the droplet to be transported by manipulating the three-axis translation device, and then lowered to make the photoresponsive bilayer heterogeneous membrane contact with the droplet to form adhesion;

[0024] The photoresponsive double-layer heterogeneous membrane is driven to move to the target position by manipulating the three-axis translation device, and the light source is turned on to make the photoresponsive double-layer heterogeneous membrane bend and deform toward the light source, so that the droplet is separated from the photoresponsive double-layer heterogeneous membrane and falls off;

[0025] The wavelength of the light source is adjusted to restore the photoresponsive double-layer heterogeneous membrane to its initial state, and then the three-axis translation device is manipulated to reset the photoresponsive double-layer heterogeneous membrane to standby or enter the next cycle.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention uses light as a driving source for manipulating droplets to perform grabbing and releasing actions. Compared with other driving sources such as electric fields and magnetic fields, it has the advantages of small size and non-contact manipulation, so it can effectively reduce the volume of the entire three-dimensional droplet manipulation transport arm device. At the same time, light can achieve remote and precise control. The control accuracy of the droplet release is increased, and the non-contact manipulation also effectively avoids the risk of sample contamination.

[0028] In this method, the capture of droplets is achieved through the design of thin film microstructures. Compared with other smart response materials, the capture operation of all types of bio-based samples can be achieved, including high-viscosity blood, serum and other samples. In addition, the present invention can further adjust the volume of the manipulated droplets by adjusting the microstructure of the capture film, and can achieve the screening function of the droplets.

[0029] Compared with traditional micro-droplet manipulation systems such as pumping microfluidic systems, this method can achieve three-dimensional manipulation of micro-droplets and can also achieve manipulation of discontinuous liquids. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the transfer arm;

[0031] Figure 2 Schematic diagram of the preparation process of the photoresponsive double-layer heterogeneous membrane;

[0032] Figure 3 This is a real shot of the droplet transport process in Example 2;

[0033] Figure 4Electron microscope images of microarray structures at different array spacings;

[0034] Figure 5 This is a real shot of the droplet transport process in Example 3;

[0035] In the figure: 1- three-axis translation device; 2- photoresponsive double-layer heterogeneous membrane; 21- photoresponsive film; 22- polymer film; 3- light source. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Unless otherwise specified, the materials used are commercially available products and the methods adopted are conventional methods.

[0038] The purpose of the present invention is to provide a light-controlled transport arm device for accurately grabbing bio-based droplets, which can achieve precise control of the grabbing and releasing of bio-based droplets through light control. The main structure of the device is as follows Figure 1 As shown:

[0039] The main components of the present invention are a photoresponsive double-layer heterogeneous film 2 (grasping / releasing structure), a three-axis translation device 1, a light source 3 and other accessories, wherein the photoresponsive double-layer heterogeneous film 2 includes a photoresponsive film 21 that can bend and deform under light as a release unit, and a polymer film 22 that can provide sufficient adhesion as a grasping unit. In order to provide a higher adhesion, it is necessary to shape the surface of the polymer film 22 with a microstructure, and the microarray structure on the surface of the polymer film 22 can be processed and prepared by a template method or photolithography, imprinting, 3D printing, etc., and the size is in the micron level. The light source 3 has at least two switchable wavelengths, and the bending and recovery of the photoresponsive film 21 material are achieved by switching different wavelengths. The three-axis translation device 1 can realize movement in three dimensions of xyz and can be programmed through a computer host to realize programmed three-dimensional transport of droplets.

[0040] The connection method of each component is that the photoresponsive film 21 and the polymer film 22 are closely attached to each other by an adhesive to form a photoresponsive double-layer heterogeneous film 2, and the light-responsive double-layer heterogeneous film 2 is partially bonded to the output end (moving part) of the three-axis translation device 1. The lamp head of the light source 3 is placed 5-15 cm above the photoresponsive double-layer heterogeneous film 2 and is also installed on the three-axis translation device 1, so that it can synchronously follow the movement of the photoresponsive double-layer heterogeneous film 2 and always cover the photoresponsive double-layer heterogeneous film 2.

[0041] The parameters of each structure are:

[0042] The material types of the photoresponsive film 21 include, but are not limited to, engineering plastics or rubbers such as liquid crystal polymers, photoresponsive gel films, photoresponsive polyimides, and polyurethanes, with a film thickness of 10-50 μm and a length and width range of 5-50 mm. After irradiation, the film bends and deforms, the reaction time of the photoresponsive film is ≤1 second, the deformation along the illumination direction is ≥15 μm, the minimum response temperature is ≤20°C, and the maximum response temperature is ≥100°C.

[0043] The material types of the high adhesion polymer film 22 include, but are not limited to, engineering plastic films such as silicone film, hydrogel film, polyurethane, and polyimide film, with a film thickness of 10-50 μm and a length and width range of 5-50 mm. The film can be processed by one or more of the methods of template method, photolithography, hot pressing, 3D printing, etc., and the size is consistent with the photoresponsive film 21.

[0044] The light emitted by the control light source 3 is any one of ultraviolet light, visible light and near infrared light, and the light source 3 is any one of a single point light source 3, a line light source 3 and an array integrated light source 3.

[0045] The three-axis translation device 1 is of mechanical transmission type, including but not limited to a three-axis slide, a CNC machine tool, etc., with a repeat positioning accuracy within 10μm, a moving speed range of 10mm / min-100mm / min, and a controllable moving range of not less than 80mm×80mm.

[0046] The main steps of the whole device for three-dimensional manipulation of droplets are:

[0047] 1. Use a computer to manipulate the three-axis translation device 1 to move the photoresponsive double-layer heterogeneous membrane 2 to 1-10 mm above the droplet to be manipulated, and manipulate the output end of the three-axis translation device 1 to translate along the negative direction of the y-axis until it contacts the upper surface of the manipulated droplet.

[0048] 2. The output end of the three-axis translation device 1 is manipulated to lift upward along the positive direction of the y-axis. At this time, the manipulated droplet will adhere to the polymer film 22 and be lifted up accordingly. By setting the motion trajectory of the three-axis translation device 1, the droplet moves with the three-axis translation device 1 to the set release position.

[0049] 3. Turn on the light source 3 and adjust the emission wavelength to a range that can cause the light-responsive film 21 to bend and deform. The light-responsive film 21 drives the polymer film 22 to bend and deform toward the light source 3. At this time, a de-adhesion process occurs between the manipulated droplet and the film, and the droplet falls vertically to the set position.

[0050] 4. The wavelength of the light source 3 is adjusted to a range that can restore the bending deformation of the light-responsive film 21. The film returns from the bent state to the initial state, and the droplet grabbing action can be achieved again by manipulating the three-axis translation device 1.

[0051] Example 1

[0052] Further Figure 1 As shown, the main components of the transport arm are a three-axis translation device 1, a light-responsive double-layer heterogeneous film 2, a light source 3 control unit and other accessories. The light-responsive double-layer heterogeneous film 2 is formed by bonding a light-responsive film 21 and a polymer film 22. The light-responsive film 21 is a material that can bend and deform under light. The light source 3 control unit includes an adapted light-responsive film 21 to control the light source 3 and a matching light source 3 translation device. The light beam emitted by the light source 3 is a parallel light beam, which can switch between two specific wavelengths of ultraviolet / visible light. It is installed on the three-axis translation device 1 and assembled above the light-responsive film 21. Before using the transport arm, the angle of the light source 3 needs to be adjusted so that the parallel light beam can be vertically irradiated on the light-responsive film 21. This is to ensure that the light intensity received on the upper surface of the light-responsive film 21 is consistent. In addition, the distance between the light source 3 and the light-responsive film 21 needs to be adjusted to ensure that the light spot of the parallel light beam emitted by the light source 3 can completely cover the light-responsive film 21. After adjusting the light source 3 to a suitable position and angle, the light source 3 can be limited. When in use, the light source 3 will move with the three-axis translation device 1, and the relative position of the light source 3 and the light-responsive film 21 will remain unchanged during the movement. The three-axis translation device 1 is used to carry and adjust the position of the light source 3 and the light-responsive double-layer heterogeneous film 2. Commercially available products that can be moved along the left and right (x-axis), front and back (y-axis), and up and down (z-axis) can be selected. The end portion of the light-responsive double-layer heterogeneous film 2 is bonded and fixed to the three-axis translation device 1, and the light source 3 is hingedly connected to the three-axis translation device 1. The three-axis translation device 1 and the light source 3 control unit can directly adopt the structure of the existing technology. Other accessories include sealants, adhesives, connecting wires, etc.

[0053] Example 2

[0054] The above-mentioned transport arm is used to implement the transport of droplets:

[0055] 1. Preparation of photoresponsive film 21: Liquid crystal monomers C6A, DA11AB and photoinitiator Irgacure 784 were dissolved in CH 2 Cl 2 Then place it in a cool and dry place for more than 24 hours to allow the solvent to completely evaporate and obtain a light yellow powder. Place the prepared liquid crystal box on a 102°C hot plate, sprinkle the liquid crystal monomer mixture powder on the edge of the liquid crystal box in the dark, and pour it into the liquid crystal box by capillary action after melting. -1 The hot plate was slowly cooled to 90°C at a speed of 3 mW cm -2 The polymer is polymerized under 530nm green light for 3 hours. After the polymerization is completed, the liquid crystal box is opened and the polymer film 22 is cut off.

[0056] The structural formulas of the liquid crystal monomers C6A and DA11AB are shown in the following formula (a) and formula (b), respectively, wherein C6A is 2-methyl-1,4-phenylenebis(4-((6-(acryloyloxy)hexyl)oxy)benzoate), CAS: 125248-71-7; DA11AB is prepared according to the method provided in the prior art Photoinduced bending behavior of crosslinked liquid-crystalline polymer films with a long spacer. J. Mater. Chem., 2010, 20, 7123-7130.

[0057]

[0058] 2. Preparation of adhesive polymer film 22 and microarray: Place the silicon wafer template with negative microarray in acetone, clean it with an ultrasonic device for 10 minutes, take it out and place it in a blast oven, and add 5μL 1H,1H,2H,2H-perfluorooctyl trichlorosilane (1H,1H,2H,2H-perfluorooctyl trichlorosilane) next to it, then heat it to 100℃ for 2 hours and take it out to obtain a fluorinated microarray silicon wafer template. Place the treated silicon wafer template in a watch glass, pour in an appropriate amount of well-mixed PDMS prepolymer (the mass ratio of monomer to cross-linker is 10:1), then place it in a vacuum dryer and evacuate for 30 minutes until the bubbles in the PDMS completely disappear, cover the surface with a glass sheet, and then place it in an 80℃ blast oven for curing for 2 hours. Finally, cut off the PDMS microarray film with a blade.

[0059] 3. Preparation of photoresponsive double-layer heterogeneous membrane 2: Bond the clean PDMS microarray film to the photoresponsive film 21 (cross-linked liquid crystal polymer, CLCP) film to avoid bubbles. Use a single-sided blade to cut the double-layer membrane into rectangles of 10mm×5mm in size, with the CLCP orientation direction along the long axis of the rectangle. Take a glass sheet of 15mm×30mm in size, apply a small amount of silicone grease on one end, and place one end of the PDMS / CLCP photoresponsive double-layer heterogeneous membrane 2 close to the glass sheet with the CLCP surface and stick them together. Finally, use double-sided tape to stick the other end of the glass sheet to the three-axis translation device 1 of Example 1.

[0060] The flow chart of steps 1-3 is as follows Figure 2 shown.

[0061] 4. After the light-responsive double-layer heterogeneous membrane 2 is fixed, the three-axis translation device 1 is used to give it a mobile function, so that the three-axis translation device 1 can cooperate with each other to complete the entire process of droplet transport. Figure 3As shown, the movement of the three-axis translation device 1 on the z axis can help the photoresponsive double-layer heterogeneous membrane 2 approach the droplet and capture the droplet. The movement on the xyz axis can transfer the droplet to any position in the plane space. Then, the ultraviolet light emitted by the light source 3 can irradiate the photoresponsive double-layer heterogeneous membrane 2 to release the droplet. Finally, the green light emitted by the light source 3 can irradiate the photoresponsive double-layer heterogeneous membrane 2 to restore it to the stretched state. After the cycle is completed, no other factors change except the position of the droplet, so the process is repeatable and reversible.

[0062] The transport arm enables screening of bio-based micro-droplets of different volumes:

[0063] By changing the spacing of the microarray structures on the microarray PDMS surface, such as Figure 4 , the adhesion force to the droplets can be adjusted to achieve precise control of droplets of different volumes.

[0064] Example 3

[0065] The above-mentioned light-controlled transport arm is used to realize the chemical reaction of micro-droplets:

[0066] The light-controlled three-dimensional droplet transport technology of the present invention releases droplets only through the imbalance of force on the droplets. The entire transport process does not involve changes in surface properties, so it can manipulate many liquids that were previously impossible to transport, which will greatly enhance the application of droplet manipulation on the surface in trace reactions and biochemical detection.

[0067] Luminol reagent is a commonly used blood test reagent that emits blue light when oxidized. There are a large number of red blood cells in the blood, and the hemoglobin in the blood contains iron, which can catalyze the decomposition of hydrogen peroxide, turning hydrogen peroxide into water and single oxygen. Single oxygen can act as an oxide to make the luminol reagent glow. Because blood contains a large amount of proteins and cells, traditional droplet manipulation technology is difficult to achieve blood transport. Figure 5 As shown, we drip hydrogen peroxide, luminol reagent and blood on the super-hydrophobic surface. First, the transport arm in Example 2 is used to mix hydrogen peroxide with luminol reagent, and then the blood is transported to further react with the mixed reagent. After the hydrogen peroxide and luminol reagent are mixed, there is no luminescence phenomenon in the dark, and obvious blue fluorescence is emitted when blood is added. This experiment shows that the droplet transport technology based on the microarray PDMS / CLCP double-layer membrane can be used for the transport of high-viscosity biological samples.

[0068] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A transport arm for light-controlled three-dimensional transport droplets, characterized in that: It comprises a light-responsive double-layer heterogeneous film (2), a three-axis translation device (1) and a light source (3); The light-responsive double-layer heterogeneous film (2) is arranged at the end of the three-axis translation device (1), and its movement is controlled by the three-axis translation device (1); The light source (3) is arranged above the light-responsive double-layer heterogeneous film (2) and moves along with the light-responsive double-layer heterogeneous film (2); The light-responsive double-layer heterogeneous film (2) is formed by stacking a light-responsive film (21) and a polymer film (22); the light-responsive film (21) deforms when irradiated by a light source (3), and the polymer film (22) is provided with a microarray structure on its surface for adhering droplets.

2. A transport arm for light-controlled three-dimensional transport droplets according to claim 1, characterized in that: The material of the light-responsive film (21) includes liquid crystal polymer, light-responsive gel film, light-responsive polyimide and polyurethane; the light-responsive time of the light-responsive film (21) does not exceed 1 second, and the deformation amount is not less than 15 μm.

3. A transport arm for light-controlled three-dimensional transport of droplets according to claim 2, characterized in that: The thickness of the photoresponsive film (21) is 10-50 μm, and the length and width are in the range of 5-50 mm; the lowest response temperature of the photoresponsive film (21) is not higher than 20° C., and the highest response temperature is not lower than 100° C.

4. The transport arm for light-controlled three-dimensional transport droplets according to claim 1, characterized in that: The material of the polymer film (22) includes a silicone film, a hydrogel film, a polyurethane and a polyimide film; the microarray structure is produced by one or more of a template method, a photolithography method, a hot pressing method and a 3D printing method.

5. The transport arm for light-controlled three-dimensional transport droplets according to claim 4, characterized in that: The polymer film (22) has a thickness of 10-50 μm, and a length and width of 5-50 mm.

6. The transport arm for light-controlled three-dimensional transport droplets according to claim 1, characterized in that: The light source (3) is a single point light source, a line light source or an array integrated light source, and the light beam emitted by the light source (3) is one or more of an ultraviolet light source, a visible light source and a near-infrared light source.

7. The transport arm for light-controlled three-dimensional transport droplets according to claim 6, characterized in that: The light source (3) is arranged 5-15 cm above the light-responsive double-layer heterogeneous film (2).

8. The transport arm for light-controlled three-dimensional transport droplets according to claim 1, characterized in that: The three-axis translation device (1) is a three-axis slide table or a CNC machine tool.

9. The transport arm for light-controlled three-dimensional transport droplets according to claim 1, characterized in that: The photoresponsive film (21) is bonded and fixed to the polymer film (22), and the photoresponsive double-layer heterogeneous film (2) is bonded and fixed to the three-axis translation device (1).

10. The transport arm for light-controlled three-dimensional transport of droplets according to claim 9, characterized in that: The light-responsive double-layer heterogeneous film (2) is bonded to the end of the three-axis translation device (1) via a glass sheet.

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