Digital microfluidic device and method of driving the same

Abstract

This disclosure provides an exemplary embodiment of a digital microfluidic device and its driving method. The digital microfluidic device includes a digital microfluidic chip, a thermal control device, and an elastic support device. The digital microfluidic chip has a droplet channel configured for droplet movement within it. The thermal control device is disposed on one side of the digital microfluidic chip and configured to generate at least two independent and non-interfering hot zones within the droplet channel, and control the temperature of the hot zones. The elastic support device is disposed on the side of the thermal control device away from the digital microfluidic chip and configured to drive the thermal control device to adhere to the surface of the digital microfluidic chip. This disclosure achieves rapid temperature change of the droplet by forming multiple independent and non-interfering hot zones on the digital microfluidic chip, allowing the droplet to circulate and move repeatedly within these zones.

Description

Technical Field

[0001] This disclosure relates to, but is not limited to, the field of chemiluminescence detection technology, specifically to a digital microfluidic device and its driving method. Background Technology

[0002] With the development of microelectromechanical systems (MEMS) technology, digital microfluidics (MicroFluidics) has made breakthroughs in the driving and control of microdroplets, and has been widely applied in fields such as biology, chemistry, and medicine due to its inherent advantages. Digital microfluidics is an emerging interdisciplinary field involving chemistry, fluid physics, microelectronics, new materials, biology, and biomedical engineering, enabling precise control and manipulation of tiny droplets. Due to its miniaturization and integration characteristics, devices employing microfluidics technology are often called digital microfluidic chips, which are an important component of laboratory-on-a-chip (LOC) systems. Various samples, such as cells, can be cultured, moved, detected, and analyzed within digital microfluidic chips, demonstrating enormous development potential and broad application prospects.

[0003] In recent years, digital microfluidic chips have been increasingly applied to polymerase chain reaction (PCR) due to their advantages of low sample volume and high sensitivity. The inventors of this application have found that existing digital microfluidic devices used in PCR reactions suffer from problems such as slow temperature change rates, large temperature overshoot, complex structures, and large sizes.

[0004] Public content

[0005] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0006] The technical problem to be solved by the exemplary embodiments disclosed herein is to provide a digital microfluidic device and its driving method to solve the problems of slow temperature change rate and large temperature change overshoot in existing structures.

[0007] To address the aforementioned technical problems, an exemplary embodiment of this disclosure provides a digital microfluidic device, characterized in that it includes a digital microfluidic chip, a thermal control device, and an elastic support device; the digital microfluidic chip is provided with a droplet channel configured to allow droplets to move therebetween; the thermal control device is disposed on one side of the digital microfluidic chip and configured to generate at least two independent and non-interfering hot zones within the droplet channel, and control the temperature of the hot zones; the elastic support device is disposed on the side of the thermal control device away from the digital microfluidic chip, and the elastic support device is configured to drive the thermal control device to adhere to the surface of the digital microfluidic chip.

[0008] In an exemplary embodiment, the thermal control device includes a support body and at least two thermal control bodies; the support body has at least two grooves on the side facing the digital microfluidic chip, and the at least two thermal control bodies are respectively disposed in the at least two grooves, with a minimum distance between adjacent thermal control bodies of 0.1 mm to 4 mm.

[0009] In an exemplary embodiment, the thermal control body has one or more of the following shapes in a plane parallel to the digital microfluidic chip: square, rectangle, circle, and ellipse; the characteristic length of the thermal control body is greater than 3 times the droplet diameter.

[0010] In an exemplary embodiment, the thermal control body includes a stacked heat source and a heat transfer body. The heat source is disposed within the groove and configured to provide a heat source. The heat transfer body is disposed on the side of the heat source near the digital microfluidic chip and configured to conduct heat from the heat source. The sum of the thicknesses of the heat source and the heat transfer body is greater than the depth of the groove.

[0011] In an exemplary embodiment, the difference between the sum of the thicknesses of the heat source and the heat transfer body and the depth of the groove is 0.5 mm to 2 mm.

[0012] In an exemplary embodiment, the digital microfluidic device further includes a temperature sensor; one side of the support body is provided with at least one first through hole, the first through hole penetrating the sidewall of the groove; one side of the heat transfer body is provided with at least one sensor hole, the sensor hole communicating with the first through hole, and the temperature sensor is inserted into the sensor hole.

[0013] In an exemplary embodiment, the heat source body further includes a connector; one side of the support body is provided with at least one second through hole, the second through hole penetrating the side wall of the groove; one side of the heat source body is provided with at least one connection hole, the connection hole communicating with the second through hole, and the connector is inserted into the connection hole.

[0014] In an exemplary embodiment, the elastic support device includes an elastic element and a support frame; the support frame includes a bottom frame, a side frame, and a top frame; the bottom frame is a plate-like structure, the top frame is a plate-like structure with a first opening in the middle, the side frame is a cylindrical structure, a first end of the side frame is connected to the outer edge of the bottom frame, and a second end of the side frame is connected to the outer edge of the top frame, so that the bottom frame, side frame, and top frame form a first accommodating cavity for accommodating the elastic element and the thermal control device, and the first opening communicates with the first accommodating cavity; the end of the elastic element away from the digital microfluidic chip is connected to the bottom frame, and the end of the elastic element close to the digital microfluidic chip is connected to the thermal control device; the elastic element is configured to apply an elastic force to the thermal control device, causing the thermal control device to extend into the first opening and adhere to the surface of the digital microfluidic chip.

[0015] In an exemplary embodiment, the digital microfluidic chip further includes a cover frame disposed on the side of the digital microfluidic chip away from the thermal control device. The cover frame includes a front frame and a side frame. The front frame is a plate-like structure with a second opening in the middle, and the side frame is a cylindrical structure. A first end of the side frame is connected to the support frame, and a second end of the side frame is connected to the outer edge of the front frame, so that the front frame, the side frame, and the support frame form a second accommodating cavity for accommodating the digital microfluidic chip, thereby fixing the digital microfluidic chip in the second accommodating cavity.

[0016] In an exemplary embodiment, the elastic element includes 3 to 6 springs, the compression distance of which is 1 mm to 3 mm.

[0017] In an exemplary embodiment, the elastic support device includes an elastic element, a support column, and a support base; the support base is a plate-like structure with a first opening in the middle; the end of the elastic element away from the digital microfluidic chip is connected to the support column, and the end of the elastic element near the digital microfluidic chip is connected to the thermal control device; the elastic element is configured to apply an elastic force to the thermal control device, causing the thermal control device to extend into the first opening and adhere to the surface of the digital microfluidic chip.

[0018] In an exemplary embodiment, the digital microfluidic chip further includes a cover frame disposed on the side of the digital microfluidic chip away from the thermal control device. The cover frame includes a front frame and a side frame. The front frame is a plate-like structure with a second opening in the middle, and the side frame is a cylindrical structure. A first end of the side frame is connected to the support base, and a second end of the side frame is connected to the outer edge of the front frame, so that the front frame, the side frame, and the support base form a second accommodating cavity for accommodating the digital microfluidic chip, thereby fixing the digital microfluidic chip in the second accommodating cavity.

[0019] In an exemplary embodiment, the digital microfluidic device further includes a calibration sensor and a temperature controller, the temperature controller being connected to both the temperature sensor and the calibration sensor. The calibration sensor is configured to: be mounted on the digital microfluidic chip during the calibration phase to collect the temperature of the hot zone; the temperature controller is configured to: acquire the hot zone temperature collected by the calibration sensor during the calibration phase, obtain a calibration value based on the hot zone temperature, acquire the heat transfer body temperature collected by the temperature sensor during the testing phase, and control the heating amount of the heat source body based on the heat transfer body temperature and the calibration value.

[0020] This exemplary embodiment also provides a digital microfluidic driving method using the above-described digital microfluidic device, including:

[0021] S1. Independent and non-interfering first hot zone, second hot zone, and third hot zone are generated on the digital microfluidic chip, respectively. The first hot zone has a first temperature for performing the denaturation step, the second hot zone has a second temperature for performing the extension step, and the third hot zone has a third temperature for performing the annealing step; or, independent and non-interfering first hot zone and second hot zone are generated on the digital microfluidic chip, respectively. The first hot zone has a first temperature for performing the denaturation step, and the second hot zone has a second temperature for performing the annealing step and the extension step.

[0022] S2. Performing a polymerase chain reaction cycle, comprising: moving the droplet to the first hot zone to denature the nucleic acid; moving the droplet to the third hot zone to bind the primer to the nucleic acid template, forming a local double strand; moving the droplet to the second hot zone to synthesize a nucleic acid strand complementary to the template; or, moving the droplet to the first hot zone to denature the nucleic acid; moving the droplet to the second hot zone to bind the primer to the nucleic acid template, forming a local double strand, and synthesizing a nucleic acid strand complementary to the template;

[0023] S3. Repeat the polymerase chain reaction cycle.

[0024] In an exemplary embodiment, prior to step S1, the method further includes:

[0025] Determine whether it is the calibration stage; if so, perform calibration processing; otherwise, proceed to step S1.

[0026] The correction process includes:

[0027] A calibration sensor is disposed in at least one hot zone of the digital microfluidic chip;

[0028] The temperature controller acquires the heat transfer body temperature collected by the temperature sensor and the hot zone temperature collected by the calibration sensor; calculates the difference between the heat transfer body temperature and the hot zone temperature, and stores the difference as a calibration value.

[0029] Remove the calibration sensor from the digital microfluidic chip.

[0030] This disclosure provides an exemplary embodiment of a digital microfluidic device and its driving method. By forming multiple independent and non-interfering hot zones on a digital microfluidic chip, the droplet can achieve rapid temperature change by cyclically moving within these zones. The temperature change rate is far greater than the maximum temperature change rate of existing structures. The digital microfluidic device provided by this disclosure does not require temperature overshoot, which not only further shortens the temperature stabilization time but also avoids the impact of temperature overshoot on enzyme activity. This disclosure simplifies the structure to the greatest extent possible, offering advantages such as simple structure, small size, and low cost.

[0031] Of course, implementing any product or method of this disclosure does not necessarily require achieving all of the advantages described above simultaneously. Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description and embodiments, or may be learned by practicing this disclosure. The objectives and other advantages of exemplary embodiments of this disclosure may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings.

[0032] After reading and understanding the accompanying diagrams and detailed descriptions, other aspects can be understood. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the technical solutions of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure. The shapes and sizes of the components in the drawings do not reflect actual proportions and are only intended to illustrate the content of this disclosure.

[0034] Figure 1 This is a schematic diagram of the structure of a digital microfluidic device, which is an exemplary embodiment of the present disclosure.

[0035] Figures 2a to 2c This is a schematic diagram of the structure of a digital microfluidic chip according to an embodiment of the present disclosure;

[0036] Figure 3 This is a schematic diagram of the structure of another digital microfluidic chip according to an embodiment of the present disclosure;

[0037] Figure 4 This is a schematic diagram of the structure of another digital microfluidic chip according to an embodiment of the present disclosure;

[0038] Figure 5This is a schematic diagram of the structure of another digital microfluidic chip according to an embodiment of the present disclosure;

[0039] Figures 6a to 6b This is a schematic diagram of the structure of a thermal control device according to an embodiment of the present disclosure;

[0040] Figure 7 This is a schematic diagram of the structure of an elastic support device according to an embodiment of the present disclosure;

[0041] Figure 8 This is a schematic diagram of the structure of a cover plate according to an embodiment of the present disclosure;

[0042] Figure 9 This is a schematic diagram of another digital microfluidic device according to an embodiment of the present disclosure;

[0043] Figures 10a to 10c This is a schematic diagram of the temperature distribution in the hot zone according to an embodiment of this disclosure;

[0044] Figure 11 This is a graph showing the results of a repeatability test of the hot zone in an embodiment of this disclosure;

[0045] Figures 12a to 12b This is a schematic diagram of another elastic support device according to an embodiment of the present disclosure;

[0046] Figure 13 This is a three-dimensional structural schematic diagram of another digital microfluidic device according to an embodiment of the present disclosure;

[0047] Figure 14 This is a schematic diagram of the appearance of a digital microfluidic device according to an embodiment of the present disclosure.

[0048] Explanation of reference numerals in the attached figures:

[0049] 10—Digital microfluidic chip; 11—First substrate; 12—Second substrate;

[0050] 13—Sealing adhesive; 14—Liquid inlet; 20—Thermal control device;

[0051] 21—Support body; 22—Thermal control body; 23—Heat source body;

[0052] 24—Heat transfer element; 30—Elastic support device; 31—Support frame;

[0053] 32—Elastic element; 33—First opening; 34—First accommodating cavity;

[0054] 35—Support column; 36—Support base frame; 40—Cover frame;

[0055] 41—Front frame; 42—Border edge; 43—Second opening;

[0056] 44—Second accommodating cavity; 50—Temperature sensor; 51—First hot zone;

[0057] 52—Second hot zone; 53—Third hot zone; 60—Calibration sensor;

[0058] 70—Temperature controller; 80—Input / output device; 90—Droplet;

[0059] 91—Droplet channel; 100—Base frame; 110—First substrate;

[0060] 111—First electrode layer; 112—First protective layer; 113—First hydrophobic layer;

[0061] 120—Second substrate; 121—Second electrode layer; 122—Second protective layer;

[0062] 123—Second hydrophobic layer; 210—Groove; 220—First through hole;

[0063] 230—Second through hole; 231—Connecting hole; 232—Connecting piece;

[0064] 241—Sensor hole; 311—Bottom frame; 312—Side frame;

[0065] 313—Top frame. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this disclosure clearer, embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Note that the implementation methods can be carried out in many different forms. Those skilled in the art will readily understand that the methods and content can be varied in various forms without departing from the spirit and scope of this disclosure. Therefore, this disclosure should not be construed as limited to the content described in the following embodiments. Without conflict, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0067] The scale of the accompanying drawings in this disclosure can be used as a reference in actual processes, but is not limited thereto. The drawings described in this disclosure are merely structural schematic diagrams, and one aspect of this disclosure is not limited to the shapes or values ​​shown in the drawings.

[0068] The ordinal numbers “first,” “second,” and “third” used in this specification are used to avoid confusion among the constituent elements, not to limit their quantity.

[0069] In this specification, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships in conjunction with the accompanying drawings. This is solely for the purpose of facilitating the description and simplification, and does not imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this disclosure. The positional relationships of the constituent elements may be appropriately varied depending on the orientation of each constituent element being described. Therefore, the use of terms not limited to those described in the specification may be appropriately replaced as needed.

[0070] In this specification, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection, an indirect connection via an intermediate component, or a connection within two components. Those skilled in the art will understand the specific meaning of these terms in this disclosure based on the specific circumstances.

[0071] In this specification, "parallel" refers to the state where the angle formed by two straight lines is greater than or equal to -10° and less than 10°, and therefore also includes the state where the angle is greater than or equal to -5° and less than 5°. Similarly, "perpendicular" refers to the state where the angle formed by two straight lines is greater than or equal to 80° and less than 100°, and therefore also includes the state where the angle is greater than or equal to 85° and less than 95°.

[0072] In this specification, triangles, rectangles, trapezoids, pentagons, or hexagons are not strictly defined; they can be approximate triangles, rectangles, trapezoids, pentagons, or hexagons. Small deformations due to tolerances are possible, as are chamfers, curved edges, and other variations.

[0073] In this disclosure, “about” means a value that is not strictly limited and allows for process and measurement errors.

[0074] Digital microfluidic chips utilize the principle of electrowetting on dielectric (EWOD). Droplets are placed on a surface with a hydrophobic layer. Through the electrowetting effect, applying a voltage to the droplet alters the wettability between the droplet and the hydrophobic layer, creating a pressure difference and asymmetric deformation within the droplet, thus achieving directional droplet movement. Digital microfluidics are divided into active and passive types. The main difference lies in their operation: active digital microfluidics drives droplets in an array, allowing precise control of individual droplet movement at a specific location, while passive digital microfluidics moves or stops all droplets simultaneously.

[0075] Typically, PCR reactions involve multiple reaction temperatures. For example, a PCR reaction can include the following three basic reaction steps: (1) DNA denaturation (90°C to 96°C), where the hydrogen bonds of the double-stranded DNA template break under heat, forming single-stranded DNA; (2) Annealing (60°C to 65°C), where the system temperature decreases, and the primers bind to the DNA template, forming local double strands; and (3) Extension (70°C to 75°C), where, under the action of Taq enzyme (which has the best activity at around 72°C), using dNTPs as raw materials, the primers are extended from the 3′ end in a direction from the 5′ to the 3′ end to synthesize a DNA strand complementary to the template. After denaturation, annealing, and extension, one cycle is completed, and the DNA content doubles. Most PCR reactions can include 25 to 35 cycles. Studies have shown that the rate of temperature switching between multiple reaction temperatures is crucial to the overall efficiency of the PCR reaction.

[0076] The inventors of this application have discovered that existing digital microfluidic devices use a cyclic heating and cooling method within a microreactor to achieve cyclic temperature switching. However, this method is limited by the heating and cooling rates of the variable temperature system, resulting in a slow temperature change rate, with a maximum rate of only 8°C / s. Furthermore, frequent heating and cooling necessitates the introduction of a temperature overshoot (approximately 3°C). This overshoot not only takes a long time to stabilize but also poses a risk of affecting enzyme activity. Moreover, the use of semiconductor cooling chips, heat sinks, and fans in the variable temperature system leads to a complex device structure, large size, and high cost.

[0077] To address the problems of slow temperature change rate, large temperature overshoot, complex structure, and large size of existing digital microfluidic devices, this exemplary embodiment provides a digital microfluidic device. Figure 1 This is a schematic diagram of the structure of a digital microfluidic device as an exemplary embodiment of this disclosure. Figure 1 As shown, a digital microfluidic device may include a digital microfluidic chip 10, a thermal control device 20, and an elastic support device 30. In an exemplary embodiment, the digital microfluidic chip 10 may be provided with droplet channels configured to allow droplets 90 to move therethrough. The thermal control device 20 is disposed on one side of the digital microfluidic chip 10 and configured to generate at least two independent and non-interfering hot zones within the droplet channels, and to control the temperature of each hot zone. The elastic support device 30 is disposed on the side of the thermal control device 20 away from the digital microfluidic chip 10 and is configured to drive the thermal control device 20 to adhere to the surface of the digital microfluidic chip 10.

[0078] In an exemplary embodiment, the digital microfluidic chip 10 may include a first substrate 11 and a second substrate 12 disposed opposite to each other. The first substrate 11 and the second substrate 12 are connected by a sealing adhesive 13, such that the first substrate 11, the second substrate 12, and the sealing adhesive 13 form a cavity with a suitable gap, and a droplet 90 of a polar material (aqueous and / or ionic) is constrained in the plane between the first substrate 11 and the second substrate 12. In an exemplary embodiment, a plurality of spacers may be disposed between the first substrate 11 and the second substrate 12, and the plurality of spacers may form a droplet channel. In an exemplary embodiment, a driving electrode may be disposed on the first substrate 11, and a reference electrode may be disposed on the second substrate 12. The driving electrode and the reference electrode are configured to drive the droplet 90 to move in the droplet channel.

[0079] In an exemplary embodiment, the digital microfluidic chip 10 may include a liquid inlet 14 configured to introduce fluid into a droplet channel.

[0080] In an exemplary embodiment, the thermal control device 20 may be disposed on the side of the first substrate 11 away from the second substrate 12, and driven by the elastic support device 30 to press against the surface of that side. In an exemplary embodiment, the thermal control device 20 may include at least a first thermal control element, a second thermal control element, and a third thermal control element. The first thermal control element is configured to generate a first hot zone within the droplet channel of the digital microfluidic chip 10 and control the first hot zone to have a first temperature. The second thermal control element is configured to generate a second hot zone within the droplet channel of the digital microfluidic chip 10 and control the second hot zone to have a second temperature. The third thermal control element is configured to generate a third hot zone within the droplet channel of the digital microfluidic chip 10 and control the third hot zone to have a third temperature. Three independent and non-interfering hot zones are formed on the digital microfluidic chip 10, that is, the three hot zones on the digital microfluidic chip are created and controlled by the thermal control device.

[0081] In an exemplary embodiment, the elastic support device 30 may include a support frame and an elastic element. The support frame may be disposed on the side of the thermal control device 20 away from the digital microfluidic chip 10. The elastic element may be disposed between the support frame and the thermal control device 20. The elastic element is configured to apply an elastic force to the thermal control device 20, so that the thermal control device 20 is pressed and adhered to the surface of the digital microfluidic chip 10.

[0082] In an exemplary embodiment, the digital microfluidic chip 10 can drive the droplet 90 from the first hot zone to the second hot zone, so that the droplet 90 rapidly changes temperature from the first temperature T1 to the second temperature T2. Alternatively, the digital microfluidic chip 10 can drive the droplet 90 from the second hot zone to the third hot zone, so that the droplet 90 rapidly changes temperature from the second temperature T2 to the third temperature T3. The temperature change rate can be greater than or equal to 12℃ / s.

[0083] By providing multiple hot zones and enabling the droplet to move rapidly between these zones, the exemplary embodiments of this disclosure make the digital microfluidic device applicable to any on-chip laboratory where it is necessary to temperature the droplet to multiple temperatures as part of a droplet manipulation scheme.

[0084] Figures 2a to 2c This is a schematic diagram of the structure of a digital microfluidic chip, which is an exemplary embodiment of the present disclosure. Figure 2a This is a schematic diagram of the three-dimensional structure of a digital microfluidic chip. Figure 2b This is a schematic diagram of the planar structure of a digital microfluidic chip. Figure 2c This is a schematic diagram of the cross-sectional structure of a digital microfluidic chip. Figure 2a and Figure 2b As shown, in an exemplary embodiment, the digital microfluidic chip 10 is provided with a droplet channel 91, which is configured to allow a droplet 90 to move therethrough. In an exemplary embodiment, the droplet channel 91 may include at least one first channel 91-1 extending along a first direction X and at least one second channel 91-2 extending along a second direction Y. The first channel 91-1 and the second channel 91-2 are interconnected to form a mesh, and the first direction X and the second direction Y intersect.

[0085] In an exemplary embodiment, a thermal control device located on the underside of the digital microfluidic chip 10 forms three independent and non-interfering hot zones on the droplet channel 91, namely a first hot zone 51, a second hot zone 52, and a third hot zone 53.

[0086] In an exemplary embodiment, the three hot zones on a plane parallel to the digital microfluidic chip can be rectangular in shape.

[0087] like Figure 2c As shown, in an exemplary embodiment, the digital microfluidic chip 10 may include a first substrate 11 and a second substrate 12 disposed opposite to each other. The first substrate 11 may include a first base 110, a first electrode layer 111 disposed on the side of the first base 110 near the second substrate 12, a first protective layer 112 disposed on the side of the first electrode layer 111 near the second substrate 12, and a first hydrophobic layer 113 disposed on the side of the first protective layer 112 near the second substrate 12. The second substrate 12 may include a second base 120, a second electrode layer 121 disposed on the side of the second base 120 near the first substrate 11, a second protective layer 122 disposed on the side of the second electrode layer 121 near the first substrate 11, and a second hydrophobic layer 123 disposed on the side of the second protective layer 122 near the first substrate 11.

[0088] In an exemplary embodiment, the first electrode layer 111 may include a plurality of first electrodes, which are spaced apart and positioned corresponding to the droplet channel, configured to drive the droplet to move within the droplet channel. The material of the first electrode layer 111 may be a metallic material, such as silver (Ag), copper (Cu), aluminum (Al), or molybdenum (Mo), or an alloy material composed of metals, such as aluminum-neodymium alloy (AlNd) or molybdenum-niobium alloy (MoNb). The alloy material may be a single-layer structure or a multi-layer composite structure, such as a composite structure composed of Mo, Cu, and Mo layers. A first protective layer 112 covers the first electrode layer 111 and has good insulation properties. The material of the first protective layer 112 may be an insulating material, such as resin, polyimide (PI), silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON), and may be a single-layer structure or a multi-layer composite structure. A first hydrophobic layer 113 has good hydrophobicity, giving the droplet 90 a large surface tension when in direct contact with it. The contact angle between droplet 90 and the first hydrophobic layer 113 is the initial contact angle. By applying a voltage to the corresponding first electrode, the first hydrophobic layer 113 at the corresponding position of the first electrode accumulates charges, thereby changing the wetting characteristics between the first hydrophobic layer 113 and the droplet 90 attached to the surface of the first hydrophobic layer 113. This causes a change in the contact angle between droplet 90 and the first hydrophobic layer 113, resulting in deformation of droplet 90 and generating a pressure difference inside droplet 90, thus achieving manipulation of droplet 90. The material of the first hydrophobic layer 113 can be a fluoropolymer such as Teflon or perfluorinated resin (CYTOP).

[0089] In an exemplary embodiment, if the first protective layer 112 has good hydrophobicity, the droplet 90 can be configured to directly contact the first protective layer 112. The first substrate 11 may include a first base 110, a first electrode layer 111, and a first protective layer 112. If the first hydrophobic layer 113 has good insulating properties, the first hydrophobic layer 113 can be configured to directly cover the first electrode layer 111. The first substrate 11 may include a first base 110, a first electrode layer 111, and a first hydrophobic layer 113. This disclosure does not limit the scope of the invention.

[0090] In an exemplary embodiment, the second electrode layer 121 may include a reference electrode configured to apply a reference potential to provide a reference voltage to a plurality of first electrodes, thereby creating a large voltage difference between the first electrodes and the reference electrode, which in turn enables a large driving voltage to control the movement of the droplet 90. In one exemplary embodiment, the reference electrode may be a surface electrode, the orthographic projection of which on the first substrate includes the orthographic projections of the plurality of first electrodes on the first substrate. In another exemplary embodiment, the reference electrode may be a plurality of strip electrodes. For example, the strip-shaped reference electrode may be a strip shape extending along a first direction X, and the orthographic projection of each strip-shaped reference electrode on the first substrate includes the orthographic projections of a plurality of first electrodes arranged sequentially in the first direction X on the first substrate. The material of the second electrode layer 121 may be a metallic material, such as silver (Ag), copper (Cu), aluminum (Al), or molybdenum (Mo), or an alloy material composed of metals, such as aluminum-neodymium alloy (AlNd) or molybdenum-niobium alloy (MoNb). The alloy material may be a single-layer structure or a multi-layer composite structure, such as a composite structure composed of a Mo layer, a Cu layer, and a Mo layer.

[0091] In an exemplary embodiment, the second protective layer 122, covering the second electrode layer 121, has good insulation properties. The material of the second protective layer 122 can be an insulating material, such as resin, polyimide (PI), silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON), and can be a single-layer structure or a multi-layer composite structure. The second liquid-repellent layer 123 has good liquid-repellent properties, giving the droplet 90 a large surface tension when in direct contact with it. The material of the second liquid-repellent layer 123 can be a fluoropolymer such as Teflon or perfluorinated resin (CYTOP).

[0092] In an exemplary embodiment, if the second protective layer 122 has good hydrophobicity, the droplet 90 can be configured to directly contact the second protective layer 122. The first substrate 11 may include a second substrate 120, a second electrode layer 121, and a second protective layer 122. If the second hydrophobic layer 123 has good insulating properties, the second hydrophobic layer 123 can be configured to directly cover the second electrode layer 121. The second substrate 12 may include a second substrate 120, a second electrode layer 121, and a second hydrophobic layer 123, which are not limited herein.

[0093] In an exemplary embodiment, on a plane parallel to the digital microfluidic chip, the shape of the first electrode can be any one or more of the following: square, rectangle, rhombus, trapezoid, polygon, circle, and ellipse. The arrangement of the first electrode can be any one or more of the following: a straight line arranged along the first direction X or the second direction Y, a cross shape, T shape, or X shape arranged along the first direction X and the second direction Y, etc., which can be determined according to the function of manipulating the droplet, and this disclosure does not limit it.

[0094] In an exemplary embodiment, the area outside the droplet channel 91 on the digital microfluidic chip 10 may include multiple virtual units. The virtual units may be equipped with corresponding first electrodes and reference electrodes, but they do not have the function of manipulating droplets.

[0095] In an exemplary embodiment, the digital microfluidic chip 10 may be a single substrate, such as including only a first substrate or only a second substrate, and this disclosure does not limit it.

[0096] The digital microfluidic chip provided in the exemplary embodiments of this disclosure controls the droplet based on the voltage generated by the electrodes, combined with the hydrophobicity between the hydrophobic layer and the droplet, and based on the dielectric wetting effect, thereby realizing the movement of the droplet in the droplet channel.

[0097] like Figures 2a to 2c As shown, the first hot zone 51, the second hot zone 52, and the third hot zone 53 can be arranged sequentially along the first direction X. M electrodes can be arranged between the first electrode corresponding to the center point of the first hot zone 51 and the first electrode corresponding to the center point of the second hot zone 52, and N electrodes can be arranged between the first electrode corresponding to the center point of the second hot zone 52 and the first electrode corresponding to the center point of the third hot zone 53. In an exemplary embodiment, M and N can be approximately 5 to 15. For example, M and N can be approximately 8. Thus, when the droplet 90 moves from the center point of the first hot zone 51 to the center point of the second hot zone 52, the droplet 90 will pass through 9 first electrodes. In an exemplary embodiment, the time taken for the droplet 90 to pass through one first electrode is approximately 0.2 seconds, and the time taken to pass through 9 first electrodes is approximately 1.8 seconds. When the temperature difference between the first hot zone 51 and the second hot zone 52 is approximately 23°C, the temperature change rate of the droplet 90 is approximately 12.8°C / s, which is much greater than the maximum temperature change rate of existing structures.

[0098] In an exemplary embodiment, the first hot zone, the second hot zone, and the third hot zone can be arranged in sequence according to an increasing or decreasing temperature to reduce temperature crosstalk between the temperature zones.

[0099] In an exemplary embodiment, the first temperature T1 of the first hot zone can be approximately 95°C ± 1°C, the second temperature T2 of the second hot zone can be approximately 72°C ± 1°C, and the third temperature T3 of the third hot zone can be approximately 60°C ± 1°C.

[0100] Figure 3 This is a schematic diagram illustrating the structure of another digital microfluidic chip according to an exemplary embodiment of the present disclosure. In this exemplary embodiment, the structure of the digital microfluidic chip is substantially the same as that of the foregoing embodiments, except that the three hot zones on the plane parallel to the digital microfluidic chip can be circular, such as... Figure 3 As shown.

[0101] In an exemplary embodiment, since the three hot zones on the digital microfluidic chip 10 are created and controlled by the three thermal control elements of the thermal control device 20, the shapes of the hot zones correspond to the shapes of the thermal control elements. For square or rectangular thermal control elements, the hot zones formed on the digital microfluidic chip 10 are substantially square or rectangular. For circular or elliptical thermal control elements, the hot zones formed on the digital microfluidic chip 10 are substantially circular or elliptical.

[0102] Figure 4 This is a schematic diagram illustrating the structure of another digital microfluidic chip according to an exemplary embodiment of the present disclosure. In this exemplary embodiment, the structure of the digital microfluidic chip is substantially the same as that of the foregoing embodiments, except that two hot zones are formed on the digital microfluidic chip 10, such as... Figure 4 As shown.

[0103] In an exemplary embodiment, for a digital microfluidic device applied to a PCR reaction, when the required primer annealing temperature and extension temperature differ by no more than 3°C, annealing and extension can be performed in a single hot zone, combining annealing and extension into one step (e.g., 60°C), i.e., two-step PCR. The two-step PCR method eliminates the need to switch between annealing and extension, thereby shortening the PCR time. In this case, two hot zones can be formed on the digital microfluidic chip 10, driving droplets to circulate between the two temperature zones to achieve the reaction.

[0104] Figure 5This is a schematic diagram of the structure of another digital microfluidic chip according to an exemplary embodiment of the present disclosure. In this exemplary embodiment, the structure of the digital microfluidic chip is basically the same as that of the aforementioned embodiments, except that the digital microfluidic chip is provided with three droplet channels 91 for biochemical reactions. A thermal control element generates hot zones of the same temperature in the three droplet channels 91, allowing each hot zone to cover all three droplet channels. Droplets 90 in each droplet channel can circulate within the three hot zones according to a corresponding driving sequence, enabling simultaneous completion of multi-channel biochemical reactions, such as... Figure 5 As shown.

[0105] Figures 6a to 6b This is a schematic diagram of the structure of a thermal control device, which is an exemplary embodiment of the present disclosure. Figure 6a This is a three-dimensional structural diagram of the thermal control device. Figure 6b This is a schematic diagram of an explosion involving a thermal control device. Figure 6a and Figure 6b As shown, in an exemplary embodiment, the thermal control device 20 may include a support body 21 and a plurality of thermal control bodies 22. The support body 21 is configured to carry the plurality of thermal control bodies 22. The plurality of thermal control bodies 22 are respectively disposed in the support body 21 and are configured to form a plurality of hot zones on the digital microfluidic chip.

[0106] In an exemplary embodiment, the support body 21 may be cuboid in shape, and a plurality of grooves 210 are provided on the third-direction Z side (the side facing the digital microfluidic chip). The plurality of grooves 210 are configured to install and fix a plurality of thermal control bodies 22, and the third-direction Z may be perpendicular to the plane of the digital microfluidic chip.

[0107] In an exemplary embodiment, a plurality of grooves 210 may be arranged sequentially along the first direction X, and the minimum distance between adjacent grooves 210 may be approximately 0.1 mm to 4 mm.

[0108] In an exemplary embodiment, the shape of the groove 210 in the plane parallel to the digital microfluidic chip can be any one or more of the following: square, rectangle, circle, and ellipse.

[0109] In an exemplary embodiment, for a square-shaped groove 210, the side length of the groove 210 can be used as a characteristic length of the groove, and can be greater than 3 times the droplet diameter. For a droplet with a diameter of approximately 3 mm, the side length of the groove 210 can be approximately 10 mm. For a rectangular-shaped groove 210, the long side of the rectangle extends along the first direction X, and the long side of the groove 210 can be used as a characteristic length of the groove, and can be greater than 3 times the droplet diameter. For a circular-shaped groove 210, the diameter of the groove 210 can be used as a characteristic length of the groove, and can be greater than 3 times the droplet diameter. For an elliptical-shaped groove 210, the major axis of the ellipse extends along the first direction X, and the major axis of the groove 210 can be used as a characteristic length of the groove, and can be greater than 3 times the droplet diameter.

[0110] In an exemplary embodiment, the support 21 may be made of a material with good thermal insulation and heat resistance, such as bakelite or acrylic.

[0111] In an exemplary embodiment, the shape of the thermal control body 22 in the plane parallel to the digital microfluidic chip can be substantially the same as the shape of the groove 210, and can be any one or more of the following: square, rectangular, circular and elliptical.

[0112] In an exemplary embodiment, the size of the thermal control body 22, parallel to the plane of the digital microfluidic chip, can be slightly smaller than the size of the recess 210. For a square-shaped thermal control body 22, the side length of the square can be used as the characteristic length of the thermal control body, and can be greater than 3 times the droplet diameter. For a droplet with a diameter of approximately 3 mm, the side length of the thermal control body 22 can be approximately 10 mm. For a rectangular-shaped thermal control body 22, the long side of the rectangle extends along the first direction X, and the long side can be used as the characteristic length of the thermal control body, and can be greater than 3 times the droplet diameter. For a circular-shaped thermal control body 22, the diameter of the circle can be used as the characteristic length of the thermal control body, and can be greater than 3 times the droplet diameter. For an elliptical-shaped thermal control body 22, the major axis of the ellipse extends along the first direction X, and the major axis can be used as the characteristic length of the thermal control body, and can be greater than 3 times the droplet diameter.

[0113] In an exemplary embodiment, a square-shaped thermal control body 22 can form a square hot zone on the digital microfluidic chip; a rectangular-shaped thermal control body 22 can form a rectangular hot zone on the digital microfluidic chip; a circular-shaped thermal control body 22 can form a circular hot zone on the digital microfluidic chip; and an elliptical-shaped thermal control body 22 can form an elliptical hot zone on the digital microfluidic chip. The circular-shaped thermal control body 22 has advantages such as a small contact area with the digital microfluidic chip and less likelihood of affecting reagent reactions in areas other than the hot zone.

[0114] In an exemplary embodiment, each thermal control body 22 may include a stacked heat source body 23 and a heat transfer body 24. The heat source body 23 is disposed in the groove 210 and configured to provide a heat source. The heat transfer body 24 is disposed on the Z-direction side of the heat source body 23 and configured to conduct the heat of the heat source body 23, thereby forming multiple hot zones on the digital microfluidic chip.

[0115] In an exemplary embodiment, the sum of the thicknesses of the heat source 23 and the heat transfer element 24 can be greater than the depth of the groove 210, causing a portion of the heat transfer element 24 to protrude from the groove 210, i.e., the surface of the heat transfer element 24 on the third X-direction side is higher than the surface of the support 21 on the third X-direction side. In this disclosure, the depth of the groove, the thickness of the heat source, and the thickness of the heat transfer element are all dimensions in the third Z-direction.

[0116] In an exemplary embodiment, the difference between the sum of the thicknesses of the heat source and the heat transfer body and the depth of the groove can be approximately 0.5 mm to 2 mm.

[0117] In an exemplary embodiment, the heat transfer body 24 can be made of a material with good thermal conductivity, such as aluminum or copper. The heat transfer body 24 is in direct contact with the surface of the first substrate in the digital microfluidic chip away from the second substrate, so as to uniformly transfer the heat generated by the heat source body 23 to the digital microfluidic chip and form a hot zone on the digital microfluidic chip.

[0118] In an exemplary embodiment, at least one first through hole 220 may be provided on one side of the support body 21 in the second direction Y or on the side opposite to the second direction Y. The at least one first through hole 220 may be located in the area where at least one groove 210 is located and penetrates the sidewall of the groove 210. At least one sensor hole 241 may be provided on one side of the heat transfer body 24 in the second direction Y or on the side opposite to the second direction Y. The sensor hole 241 is configured to mount and fix the temperature sensor 50. In an exemplary embodiment, the sensor hole 241 may be a blind hole. After the heat transfer body 24 is placed in the groove 210, the positions of the first through hole 220 and the sensor hole 241 correspond, and the first through hole 220 and the sensor hole 241 are connected, allowing the temperature sensor 50 to pass through the first through hole 220 and be inserted into the sensor hole 241.

[0119] In an exemplary embodiment, the temperature sensor 50 is configured to sense the temperature of the heat transfer body 24. The temperature sensor 50 may include a sensing head and a sensing rod. The sensing head may be disc-shaped and has a temperature sensing element disposed therein, such as an NTC thermistor, a PTC thermistor, a platinum resistance thermometer, a thermocouple, etc. The sensing head may be disposed at the end of the sensing rod so that the sensing head can extend into the interior of the heat transfer block, such as the central region of the heat transfer block, to sense the temperature inside the heat transfer body 24.

[0120] In an exemplary embodiment, after the temperature sensor 50 is inserted into the sensor hole 241, the sensor hole 241 can be filled with silicone or silicone grease with good thermal conductivity to fix the temperature sensor 50.

[0121] In an exemplary embodiment, at least one second through hole 230 may be provided on one side of the support body 21 in the second direction Y or on the side opposite to the second direction Y. The at least one second through hole 230 may be located in the area where at least one groove 210 is located and penetrates the sidewall of the groove 210. At least one connecting hole 231 may be provided on one side of the heat source body 23 in the second direction Y or on the side opposite to the second direction Y. The connecting hole 231 is configured to install and fix the connector 232. In an exemplary embodiment, the connecting hole 231 may be a blind hole. After the heat source body 23 is placed in the groove 210, the positions of the second through hole 230 and the connecting hole 231 correspond, and the second through hole 230 and the connecting hole 231 communicate, allowing the connector 232 to pass through the second through hole 230 and be inserted into the connecting hole 231.

[0122] In an exemplary embodiment, the heat source 23 can be a ceramic heating plate, which has advantages such as good thermal conductivity, uniform heating, good heat preservation performance, corrosion resistance, and long service life. The connector 232 can be rod-shaped, with one end connected to the power supply and the other end electrically connected to the heat source 23 by being inserted into the connector hole 231.

[0123] Figure 7 This is a schematic diagram of the structure of an elastic support device as an exemplary embodiment of this disclosure. Figure 7 As shown, in an exemplary embodiment, the elastic support device 30 may include a support frame 31 and an elastic element 32. One end of the elastic element 32 away from the digital microfluidic chip 10 is connected to the support frame 31, and the other end of the elastic element 32 near the digital microfluidic chip 10 is connected to the thermal control device 20. The elastic element 32 is configured to apply an elastic force to the thermal control device 20, so that the thermal control device 20 is attached to the surface of the digital microfluidic chip 10.

[0124] In an exemplary embodiment, the support frame 31 may include a bottom frame 311, a side frame 312, and a top frame 313. The bottom frame 311 may be a plate-like structure, the top frame 313 may be a plate-like structure with a first opening 33 in the middle, and the side frame 312 may be a cylindrical structure. The first end of the side frame 312 is connected to the outer edge of the bottom frame 311, and the second end of the side frame 312 is connected to the outer edge of the top frame 313, so that the bottom frame 311, the side frame 312, and the top frame 313 form a first receiving cavity 34 that can accommodate the elastic element 32 and the heat control device 20, and the first opening 33 communicates with the first receiving cavity 34.

[0125] In an exemplary embodiment, one end of the elastic element 32 is connected to the bottom frame 311, and the other end of the elastic element 32 is connected to the surface of the heat control device 20 near the bottom frame 311. In the heat control device 20, which is elastically supported by the elastic element 32, the side near the elastic element 32 is disposed in the first accommodating cavity 34, and the side away from the elastic element 32 extends out from the first opening 33. That is, the distance between the surface of the heat control device 20 away from the bottom frame 311 and the bottom frame 311 is greater than the distance between the surface of the top frame 313 away from the bottom frame 311 and the bottom frame 311.

[0126] In an exemplary embodiment, the elastic element 32 may be three to six springs, which are respectively connected to the base frame 311 and the thermal control device 20.

[0127] In an exemplary embodiment, the thermal control device is connected to multiple springs (i.e., when the digital microfluidic chip is not loaded), and the length of the springs is L1.

[0128] Figure 8 This is a schematic diagram of the structure of a cover plate, which is an exemplary embodiment of this disclosure. Figure 8 As shown, in an exemplary embodiment, the digital microfluidic device may further include a cover frame 40, which may include a front frame 41 and a side frame 42. The front frame 41 may be a plate-like structure with a second opening 43 in the middle, and the side frame 42 may be a cylindrical structure. The first end of the side frame 42 is connected to the top frame 313 of the support frame 31, and the second end of the side frame 42 is connected to the outer edge of the front frame 41, so that the front frame 41 and the side frame 42 in the cover frame 40 and the top frame 313 in the support frame 31 form a second accommodating cavity 44 capable of housing the digital microfluidic chip 10. The first opening 33 and the second opening 43 are respectively connected to the second accommodating cavity 44.

[0129] In an exemplary embodiment, the assembly process of the digital microfluidic device of the present disclosure may include: connecting the lower side of the thermal control device 20 to the elastic element 32 in the elastic support device 30, then placing the digital microfluidic chip 10 on the upper side of the thermal control device 20, then pressing the front frame 41 of the cover frame 40 onto the digital microfluidic chip 10, applying pressure to make the side frame 42 of the cover frame 40 contact the top frame 313 of the support frame 31, fixing the cover frame 40 and the support frame 31 together with a connector, and fixing the digital microfluidic chip 10 in the second accommodating cavity 44 defined between the cover frame 40 and the support frame 31.

[0130] During the pressing process, the elastic element 32 is compressed, and the elastic force of the elastic element 32 acts on the thermal control device 20, so that the multiple heat transfer bodies 24 of the thermal control device 20 are in close contact with the lower surface of the digital microfluidic chip 10, which can achieve uniform heat transfer and form multiple hot zones on the digital microfluidic chip 10.

[0131] In an exemplary embodiment, a spring is used for the elastic element 32. After the cover frame 40 is fixed to the support frame 31 (i.e., after the digital microfluidic chip is loaded), the length of the spring is L2. The compression distance L1-L2 of the spring can be set to be approximately 1mm to 3mm. This not only ensures that the thermal control device 20 and the digital microfluidic chip 10 are in close contact, but also ensures that the spring has a certain elasticity, achieving thermal stability and thermal repeatability after multiple compressions.

[0132] Figure 9 This is a schematic diagram of the structure of another digital microfluidic device as an exemplary embodiment of this disclosure. Figure 9 As shown, in an exemplary embodiment, the digital microfluidic device may include a digital microfluidic chip 10, a thermal control device 20, an elastic support device 30, a cover frame 40, a temperature sensor 50, a calibration sensor 60, a temperature controller 70, and an input / output device 80. The structures of the digital microfluidic chip 10, the thermal control device 20, the elastic support device 30, and the cover frame 40 are basically the same as those in the aforementioned embodiments, and will not be described again here.

[0133] In an exemplary embodiment, the temperature controller 70 is connected to the connector 232 inserted in the heat source 23, the temperature sensor 50 inserted in the heat transfer body 24, and the calibration sensor 60 disposed inside the digital microfluidic chip 10. The temperature controller 70 is configured to acquire a calibration value during the calibration phase, acquire the heat transfer body temperature collected by the temperature controller 70 during the testing phase, and control the heating amount of the heat source 23 through the connector 232 based on the heat transfer body temperature and the calibration value.

[0134] In an exemplary embodiment, during the calibration phase, a plurality of calibration sensors 60 may be disposed inside the digital microfluidic chip 10 and configured to collect the temperature inside the digital microfluidic chip 10. After calibration is completed, the calibration sensors 60 are removed from the digital microfluidic chip 10.

[0135] In an exemplary embodiment, during the calibration phase, multiple calibration sensors 60 can be respectively positioned at the center of multiple preset hot zones in the digital microfluidic chip 10, collecting the hot zone temperature of each hot zone at multiple temperature points. After the temperature controller 70 acquires the heat transfer body temperature collected by the temperature sensor 50 and the hot zone temperature collected by the calibration sensor 60, the difference between the heat transfer body temperature and the hot zone temperature can be obtained, and this difference can be used as a calibration value. In the subsequent testing phase, the temperature of the heat transfer body collected by the temperature controller 70 minus this calibration value can be used as the temperature value of the hot zone in the digital microfluidic chip 10.

[0136] In an exemplary embodiment, the calibration sensor 60 can be an NTC thermistor, a PTC thermistor, a platinum resistance thermometer, a thermocouple, etc., and the size of the calibration sensor 60 can be smaller than the thickness of the digital microfluidic chip 10.

[0137] In an exemplary embodiment, during the calibration phase, the temperature controller 70 acquires the heat transfer body temperature collected by the temperature sensor 50 and the hot zone temperature collected by the calibration sensor 60, respectively, and obtains the difference between the heat transfer body temperature and the hot zone temperature at each temperature point. This difference is then used as a calibration value and stored. During the testing phase, the temperature controller 70 controls the operating voltage of the heating element and the heating amount of the heat source body based on the acquired heat transfer body temperature and the pre-stored calibration value, thereby achieving the temperature control function.

[0138] In an exemplary embodiment, the input / output device 80 is communicatively connected to the temperature controller 70. The input / output device 80 is configured to allow the tester to input set temperature values ​​for multiple hot zones in the PCR reaction, send the set temperature values ​​to the temperature controller 70, receive parameters such as temperature and voltage from the temperature controller 70, and display them in real time.

[0139] In an exemplary embodiment, the digital microfluidic device may further include a driving circuit connected to the digital microfluidic chip, the driving circuit being configured to control the operation of the digital microfluidic chip via a driving signal.

[0140] In exemplary embodiments, the drive circuit may be set separately, or it may be set in the temperature controller, or it may be set in the input / output device; this disclosure does not limit this.

[0141] Figures 10a to 10c This is a schematic diagram of the temperature distribution in the hot zones according to an exemplary embodiment of this disclosure, taking a droplet diameter of approximately 3 mm as an example. In the exemplary embodiment, simulation analysis shows that when the side length of the heat transfer block is approximately 10 mm and the distance between adjacent thermal control bodies (i.e., the distance between adjacent heat transfer bodies) is approximately 3.5 mm, the standard deviation σ of the droplet temperature in the first hot zone is 0.26℃, the standard deviation σ of the droplet temperature in the second hot zone is 0.14℃, and the standard deviation σ of the droplet temperature in the third hot zone is 0.10℃. The maximum value of the standard deviation σ of the droplet temperature in the three hot zones is 0.26℃. Figure 10a As shown. According to the three-standard-deviation principle, 3σ < 1℃. Therefore, when the side length of the heat transfer block is about 10mm and the spacing is about 3.5mm, the temperature of the droplets in the three hot zones meets the accuracy requirement of ±1℃. Among them, the standard deviation of the droplet temperature σ is the finite element simulation result of the internal temperature of the droplet, used to characterize the degree of difference in the internal temperature distribution of the droplet.

[0142] In an exemplary embodiment, simulation analysis shows that when the side length of the heat transfer block is approximately 5 mm and the distance between adjacent thermal control bodies (i.e., the distance between adjacent heat transfer bodies) is approximately 3.5 mm, the standard deviation σ of the droplet temperature in the first hot zone is 0.84℃, the standard deviation σ of the droplet temperature in the second hot zone is 0.45℃, and the standard deviation σ of the droplet temperature in the third hot zone is 0.34℃. The maximum value of the standard deviation σ of the droplet temperature in the three hot zones is 0.84℃. Figure 10b As shown. According to the three-standard-deviation principle, 3σ>1℃. Therefore, when the side length of the heat transfer block is about 5mm and the spacing is about 3.5mm, the temperature of the droplets in the three hot zones does not meet the accuracy requirement of ±1℃.

[0143] In an exemplary embodiment, simulation analysis shows that when the side length of the heat transfer block is approximately 10 mm and the distance between adjacent thermal control bodies (i.e., the distance between adjacent heat transfer bodies) is approximately 0.1 mm, the standard deviation σ of the droplet temperature in the first hot zone is 0.28℃, the standard deviation σ of the droplet temperature in the second hot zone is 0.22℃, and the standard deviation σ of the droplet temperature in the third hot zone is 0.13℃. The maximum value of the standard deviation σ of the droplet temperature in the three hot zones is 0.28℃. Figure 10c As shown. According to the three-standard-deviation principle, 3σ < 1℃. Therefore, when the side length of the heat transfer block is about 10mm and the spacing is about 0.1mm, the temperature of the droplets in the three hot zones meets the accuracy requirement of ±1℃.

[0144] Simulation analysis shows that the smaller the side length of the heat transfer block, the larger the standard deviation σ of the droplet temperature, that is, the more uneven the droplet temperature distribution. When the ratio of the side length of the heat transfer block to the droplet diameter is greater than 3, the temperature of the droplets in the hot zone meets the accuracy requirement of ±1℃.

[0145] Simulation analysis shows that the spacing between adjacent heat transfer elements has no significant impact on the droplet temperature distribution. Therefore, provided that manufacturing processes allow, the spacing between heat transfer elements can be appropriately reduced to decrease the distance the droplets travel in the thermal zone and the time it takes for them to travel in the thermal zone.

[0146] Figure 11 This diagram shows the results of a repeatability test of the hot zone in an exemplary embodiment of this disclosure. Three digital microfluidic chips were tested in the same thermal control device and elastic support device. The test results show that throughout the entire workflow of the three digital microfluidic chips, the standard deviation of the droplet temperature is less than or equal to 0.06℃, and the maximum droplet temperature error is 0.48℃ (target 72℃, measured 71.52℃), indicating that the system has good temperature control stability and repeatability. Figure 11 As shown.

[0147] Figures 12a to 12b This is a schematic diagram of another elastic support device according to an exemplary embodiment of the present disclosure. Figure 12a This is a three-dimensional structural diagram of the elastic support device. Figure 12b This is a schematic diagram of an explosion involving an elastic support device. Figures 12a to 12b As shown, in an exemplary embodiment, the elastic support device 30 may include an elastic element 32, a support column 35, and a support base 36. The support base 36 may be a plate-like structure with a first opening 33 in the middle. The digital microfluidic chip 10 may be disposed on the Z-direction side of the support base 36. The cover frame 40 may be disposed on the side of the digital microfluidic chip 10 away from the support base 36. The cover frame 40 is connected to the support base 36 by a plurality of screws, thereby fixing the digital microfluidic chip 10 between the cover frame 40 and the support base 36. The elastic element 32 and the support column 35 can be disposed on the side of the support base 36 away from the digital microfluidic chip 10. The end of the elastic element 32 away from the digital microfluidic chip 10 is connected to the support column 35, and the end of the elastic element 32 close to the digital microfluidic chip 10 is connected to the thermal control device 20. The elastic element 32 is configured to apply an elastic force to the thermal control device 20, so that the thermal control device 20 extends into the first opening 33 on the support base 36 and is tightly attached to the surface of the digital microfluidic chip 10.

[0148] In an exemplary embodiment, the elastic element 32 may be a spring mechanism, which may include a base plate, a top plate, and three to six springs. The three to six springs are disposed between the base plate and the top plate and are respectively connected to the base plate and the top plate. The base plate is configured to be connected to the end of the support column 35 near the digital microfluidic chip 10, and the top plate is configured to be connected to the surface of the thermal control device 20 away from the digital microfluidic chip 10.

[0149] In an exemplary embodiment, the support column 35 can be a columnar structure, which is connected to the base plate of the elastic element 32 through a hole or the like.

[0150] Figure 13 This is a three-dimensional structural schematic diagram of yet another digital microfluidic device according to an exemplary embodiment of the present disclosure. Figure 13 As shown, the digital microfluidic device may include a digital microfluidic chip 10, a thermal control device, an elastic support device 30, a cover frame 40, a temperature controller, an input / output device 80, and a base frame 100. The structure of the digital microfluidic chip 10, the thermal control device, the elastic support device 30, and the cover frame 40 is similar to... Figures 12a to 12b The structures shown are basically the same, so they will not be described again here.

[0151] In an exemplary embodiment, the base frame 100 may include a base frame and a fixing column. The base frame may be a plate-like structure, and the fixing column may be a column-like structure. One end of the fixing column is connected to the base frame, and the other end of the fixing column is connected to the support base frame 36 of the elastic support device 30, so that the elastic support device 30 is fixed on the base frame by the fixing column, and the end of the support column 35 of the elastic support device 30 that is away from the digital microfluidic chip 10 can be placed on the base frame.

[0152] In an exemplary embodiment, the input / output device 80 may include a touch screen display, through which testers can input PCR reaction data and view the results of the PCR reaction.

[0153] Figure 14 This is a schematic diagram of the appearance of a digital microfluidic device as an exemplary embodiment of this disclosure. Figure 14 As shown, the digital microfluidic device may include a housing, a thermal control device, an elastic support device, a cover frame, and a base frame, etc., which are set inside the housing. The digital microfluidic chip and input / output devices are set on the housing, which has the advantages of simple appearance, small size and convenient operation.

[0154] As can be seen from the structure of the digital microfluidic device disclosed herein, this disclosure achieves rapid temperature change of the droplet by forming multiple independent and non-interfering hot zones on the digital microfluidic chip, allowing the droplet to circulate and move repeatedly within these zones. For example, during the process of a droplet moving from a second hot zone with a constant temperature of 72°C to a first hot zone with a constant temperature of 95°C, the droplet passes through nine first electrodes in 1.8 seconds, resulting in a temperature change rate of 12.8°C / s, far exceeding the maximum temperature change rate of existing structures. The digital microfluidic device provided by this disclosure eliminates the need for frequent heating and cooling of the heating element, significantly increasing the temperature change rate and shortening the temperature change time. Furthermore, the digital microfluidic device does not require temperature overshoot, further shortening the temperature stabilization time and avoiding the impact of temperature overshoot on enzyme activity. Since each hot zone in this disclosure does not require frequent heating and cooling, a natural cooling scheme can be used, thus avoiding the use of semiconductor cooling chips, heat sinks, fans, and other forced cooling components. This minimizes structural complexity and simplifies the structure, resulting in advantages such as simple structure, small size, and low cost.

[0155] This exemplary embodiment also provides a driving method for a digital microfluidic device employing the aforementioned digital microfluidic device. In an exemplary embodiment, the driving method for the digital microfluidic device may include:

[0156] S1. Independent and non-interfering first hot zone, second hot zone and third hot zone are generated on the digital microfluidic chip respectively. The first hot zone has a first temperature for performing the denaturation step, the second hot zone has a second temperature for performing the extension step, and the third hot zone has a third temperature for performing the annealing step.

[0157] S2. Performing a polymerase chain reaction cycle, including: moving the droplet to the first hot zone to denature the nucleic acid; moving the droplet to the third hot zone to bind the primer to the nucleic acid template to form a local double strand; and moving the droplet to the second hot zone to synthesize a nucleic acid strand complementary to the template.

[0158] S3. Repeat the polymerase chain reaction cycle.

[0159] In an exemplary embodiment, the first temperature T1 of the first hot zone can be approximately 95°C ± 1°C, the second temperature T2 of the second hot zone can be approximately 72°C ± 1°C, and the third temperature T3 of the third hot zone can be approximately 60°C ± 1°C.

[0160] In an exemplary embodiment, the first hot zone, the second hot zone, and the third hot zone can be arranged in sequence according to an increasing or decreasing temperature to reduce temperature crosstalk between the temperature zones.

[0161] In an exemplary embodiment, a determination process may be included before step S1. In an exemplary embodiment, the determination process may include:

[0162] Determine whether it is the correction stage. If it is, perform the correction process; otherwise, proceed to step S1.

[0163] In an exemplary embodiment, the correction process may include:

[0164] A calibration sensor is disposed in at least one hot zone of the digital microfluidic chip;

[0165] The temperature controller acquires the heat transfer body temperature collected by the temperature sensor and the hot zone temperature collected by the calibration sensor; calculates the difference between the heat transfer body temperature and the hot zone temperature, and stores the difference as a calibration value.

[0166] Remove the calibration sensor from the digital microfluidic chip.

[0167] In an exemplary embodiment, the first calibration sensor can be set at the center of a preset first hot zone in the digital microfluidic chip, the second calibration sensor can be set at the center of a preset second hot zone in the digital microfluidic chip, and the third calibration sensor can be set at the center of a preset third hot zone in the digital microfluidic chip, so as to collect the temperature of each hot zone as accurately as possible.

[0168] In an exemplary embodiment, a thermal control device is respectively provided with a first thermal control body, a second thermal control body, and a third thermal control body at positions corresponding to the preset first hot zone, second hot zone, and third hot zone in the digital microfluidic chip. The first thermal control body is configured to form the first hot zone, the second thermal control body is configured to form the second hot zone, and the third thermal control body is configured to form the third hot zone. The heat transfer element in the first thermal control body is provided with a first temperature sensor for acquiring the temperature of the heat transfer element; the heat transfer element in the second thermal control body is provided with a second temperature sensor for acquiring the temperature of the heat transfer element; and the heat transfer element in the third thermal control body is provided with a third temperature sensor for acquiring the temperature of the heat transfer element.

[0169] In an exemplary embodiment, the temperature controller is connected to a first calibration sensor, a second calibration sensor, a third calibration sensor, a first temperature sensor, a second temperature sensor, and a third temperature sensor, respectively, to acquire the temperatures of the three heat transfer bodies collected by the three temperature sensors and the temperatures of the three hot zones collected by the three calibration sensors. The temperature controller obtains the correction value of the first hot zone based on the temperature collected by the first calibration sensor and the first temperature sensor, obtains the correction value of the second hot zone based on the temperature collected by the second calibration sensor and the second temperature sensor, and obtains the correction value of the third hot zone based on the temperature collected by the third calibration sensor and the third temperature sensor.

[0170] Taking the set temperature value of the first hot zone as TC as an example, the specific process of the correction process may include: (1) The temperature controller controls the heat source in the first thermal control body to heat up, and acquires the heat transfer body temperature value collected by the first temperature sensor and the hot zone temperature value collected by the first correction sensor in real time. (2) When the hot zone temperature value collected by the first correction sensor is TC, the heat transfer body temperature value TW collected by the first temperature sensor is recorded. (3) The correction value is calculated, and the correction value TX = TW - TC. (4) The correction value TX is stored. In an exemplary embodiment, correction processing can be performed on multiple temperature points to obtain correction values ​​for multiple temperature points, and the set temperature value and correction value of multiple temperature points can be fitted to obtain the relationship between the two. For example, taking linear fitting as an example, y = ax + b, where x is the set temperature value, y is the correction value, and a and b are the fitted temperature coefficients obtained by calibration. The correction value at other temperature points can be obtained using this method.

[0171] In an exemplary embodiment, taking the generation of a first hot zone on a digital microfluidic chip as an example, step S1 may include:

[0172] Set the set temperature value TC1 for the first hot zone; calculate the target temperature value TW1 of the heat transfer body based on the correction value, TW1 = TC1 + TX; the temperature controller controls the heating of the heat source in the first thermal control body, acquires the heat transfer body temperature value collected by the first temperature sensor in real time, controls the working voltage based on the acquired heat transfer body temperature value and the target temperature value TW1, and stops heating when the acquired heat transfer body temperature value equals the target temperature value TW1.

[0173] In an exemplary embodiment, step S2 may include a pretreatment stage and a treatment stage. The pretreatment stage may include: a digital microfluidic chip driving a droplet to move to a first hot zone, maintaining it in the first hot zone at 95°C for 3 minutes to complete DNA pre-denaturation, and then the digital microfluidic chip driving the droplet to leave the first hot zone.

[0174] In an exemplary embodiment, the processing stage may include: a digital microfluidic chip driving a droplet to move to a first hot zone, maintaining it at 95°C for 0.5 minutes to complete DNA denaturation. Subsequently, the digital microfluidic chip driving the droplet to move to a third hot zone, maintaining it at 60°C for 0.5 minutes to complete annealing. Subsequently, the digital microfluidic chip driving the droplet to move to a second hot zone, maintaining it at 72°C for 0.5 minutes to complete extension.

[0175] In an exemplary embodiment, the repeated execution of the polymerase chain reaction cycle in step S3 is a repeated processing stage, and the number of cycles can be approximately 25 to 35.

[0176] In exemplary embodiments, the temperature of the hot zone, duration, and number of cycles may vary depending on the type of reagent, the length of the DNA fragment, etc., and this disclosure does not limit these parameters.

[0177] This exemplary embodiment also provides another driving method for a digital microfluidic device employing the aforementioned digital microfluidic device. In an exemplary embodiment, the driving method for the digital microfluidic device may include:

[0178] Independent and non-interfering first and second hot zones are generated on the digital microfluidic chip. The first hot zone has a first temperature for performing the denaturation step, and the second hot zone has a second temperature for performing the annealing and extension steps.

[0179] Performing a polymerase chain reaction cycle includes: moving the droplet to a first hot zone to denature the nucleic acid; moving the droplet to a second hot zone to bind the primer to the nucleic acid template, forming a local double strand, and synthesizing a nucleic acid strand complementary to the template;

[0180] Repeat the polymerase chain reaction cycle.

[0181] As can be seen from the driving process of the digital microfluidic device disclosed herein, by employing a method of cyclically moving the droplet across multiple thermal zones, this disclosure not only achieves rapid temperature changes in the droplet but also achieves a significantly faster temperature change rate, far exceeding the maximum temperature change rate of existing structures. The digital microfluidic device provided by this disclosure eliminates the need for frequent heating and cooling of the heating element, thereby greatly increasing the temperature change rate and significantly shortening the temperature change time. Furthermore, the digital microfluidic device provided by this disclosure does not require temperature overshoot, further shortening the temperature stabilization time and avoiding the impact of temperature overshoot on enzyme activity. Moreover, since each thermal zone in this disclosure does not require frequent heating and cooling, a natural cooling scheme can be used, thus avoiding the use of forced cooling components such as semiconductor cooling chips, heat sinks, and fans. This minimizes structural complexity and simplifies the structure to the greatest extent, resulting in advantages such as simple structure, small size, and low cost.

[0182] While the embodiments disclosed herein are as described above, the content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A digital microfluidic device, characterized in that, The device includes a digital microfluidic chip, a thermal control device, and an elastic support device. The digital microfluidic chip has droplet channels configured to allow droplets to move within them. The thermal control device is located on one side of the digital microfluidic chip and configured to generate at least two independent and non-interfering hot zones within the droplet channels, and to control the temperature of the hot zones. The elastic support device is located on the side of the thermal control device away from the digital microfluidic chip and is configured to drive the thermal control device to adhere to the surface of the digital microfluidic chip. The thermal control device includes a support body and at least two thermal control bodies. The support body has at least two grooves on the side facing the digital microfluidic chip, and the at least two thermal control bodies are respectively disposed within the at least two grooves. Each thermal control body includes a stacked heat source and a heat transfer body. The heat source is disposed within the groove and configured to provide a heat source. The heat transfer body is disposed on the side of the heat source near the digital microfluidic chip and configured to conduct heat from the heat source. The sum of the thicknesses of the heat source and the heat transfer body is greater than the depth of the groove. The at least two independent and non-interfering hot zones include: a first hot zone, a second hot zone, and a third hot zone; the first hot zone, the second hot zone, and the third hot zone are arranged in sequence according to an increasing or decreasing temperature; the digital microfluidic chip includes a plurality of first electrodes, which are spaced apart and positioned corresponding to the droplet channel, configured to drive the droplet to move within the droplet channel; M electrodes are arranged between the first electrode corresponding to the center point of the first hot zone and the first electrode corresponding to the center point of the second hot zone, and N electrodes are arranged between the first electrode corresponding to the center point of the second hot zone and the first electrode corresponding to the center point of the third hot zone, where M and N are 5 to 15.

2. The digital microfluidic device according to claim 1, characterized in that, The minimum distance between adjacent thermal control elements is 0.1 mm to 4 mm.

3. The digital microfluidic device according to claim 2, characterized in that, In a plane parallel to the digital microfluidic chip, the shape of the thermal control body is any one or more of the following: square, rectangle, circle, and ellipse; the characteristic length of the thermal control body is greater than 3 times the droplet diameter.

4. The digital microfluidic device according to claim 2, characterized in that, The difference between the sum of the thicknesses of the heat source and the heat transfer body and the depth of the groove is 0.5 mm to 2 mm.

5. The digital microfluidic device according to claim 2, characterized in that, The digital microfluidic device further includes a temperature sensor; one side of the support body is provided with at least one first through hole, which penetrates the side wall of the groove; one side of the heat transfer body is provided with at least one sensor hole, which communicates with the first through hole, and the temperature sensor is inserted into the sensor hole.

6. The digital microfluidic device according to claim 2, characterized in that, The heat source body also includes a connector; one side of the support body is provided with at least one second through hole, the second through hole penetrating the side wall of the groove; one side of the heat source body is provided with at least one connection hole, the connection hole communicating with the second through hole, and the connector is inserted into the connection hole.

7. The digital microfluidic device according to claim 1, characterized in that, The elastic support device includes an elastic element and a support frame; the support frame includes a bottom frame, a side frame, and a top frame; the bottom frame is a plate-like structure, the top frame is a plate-like structure with a first opening in the middle, the side frames are cylindrical structures, the first end of the side frame is connected to the outer edge of the bottom frame, and the second end of the side frame is connected to the outer edge of the top frame, so that the bottom frame, side frame, and top frame form a first accommodating cavity for accommodating the elastic element and the thermal control device, and the first opening communicates with the first accommodating cavity; the end of the elastic element away from the digital microfluidic chip is connected to the bottom frame, and the end of the elastic element close to the digital microfluidic chip is connected to the thermal control device, the elastic element is configured to apply an elastic force to the thermal control device, so that the thermal control device extends into the first opening and is attached to the surface of the digital microfluidic chip.

8. The digital microfluidic device according to claim 7, characterized in that, The digital microfluidic chip also includes a cover frame, which is disposed on the side of the digital microfluidic chip away from the thermal control device. The cover frame includes a front frame and a side frame. The front frame is a plate-shaped structure with a second opening in the middle, and the side frame is a cylindrical structure. The first end of the side frame is connected to the support frame, and the second end of the side frame is connected to the outer edge of the front frame, so that the front frame, the side frame, and the support frame form a second accommodating cavity for accommodating the digital microfluidic chip, thereby fixing the digital microfluidic chip in the second accommodating cavity.

9. The digital microfluidic device according to claim 7, characterized in that, The elastic element includes 3 to 6 springs, and the compression distance of the springs is 1 mm to 3 mm.

10. The digital microfluidic device according to claim 1, characterized in that, The elastic support device includes an elastic element, a support column, and a support base. The support base is a plate-shaped structure with a first opening in the middle. The end of the elastic element away from the digital microfluidic chip is connected to the support column, and the end of the elastic element close to the digital microfluidic chip is connected to the thermal control device. The elastic element is configured to apply an elastic force to the thermal control device, causing the thermal control device to extend into the first opening and adhere to the surface of the digital microfluidic chip.

11. The digital microfluidic device according to claim 10, characterized in that, The digital microfluidic chip also includes a cover frame, which is disposed on the side of the digital microfluidic chip away from the thermal control device. The cover frame includes a front frame and a side frame. The front frame is a plate-like structure with a second opening in the middle, and the side frame is a cylindrical structure. The first end of the side frame is connected to the support base, and the second end of the side frame is connected to the outer edge of the front frame, so that the front frame, the side frame, and the support base form a second accommodating cavity for accommodating the digital microfluidic chip, thereby fixing the digital microfluidic chip in the second accommodating cavity.

12. The digital microfluidic device according to any one of claims 1 to 11, characterized in that, The digital microfluidic device further includes a calibration sensor and a temperature controller, the temperature controller being connected to both the temperature sensor and the calibration sensor. The calibration sensor is configured to: be mounted on the digital microfluidic chip during the calibration phase to collect the temperature of the hot zone; the temperature controller is configured to: acquire the hot zone temperature collected by the calibration sensor during the calibration phase, obtain a calibration value based on the hot zone temperature, acquire the heat transfer body temperature collected by the temperature sensor during the testing phase, and control the heating amount of the heat source body based on the heat transfer body temperature and the calibration value.

13. A digital microfluidic driving method using the digital microfluidic device as described in any one of claims 1 to 12, characterized in that, include: S1. Independent and non-interfering first hot zone, second hot zone and third hot zone are generated on the digital microfluidic chip respectively. The first hot zone has a first temperature for performing the denaturation step, the second hot zone has a second temperature for performing the extension step, and the third hot zone has a third temperature for performing the annealing step. S2. Performing a polymerase chain reaction cycle, including: moving the droplet to the first hot zone to denature the nucleic acid; moving the droplet to the third hot zone to bind the primer to the nucleic acid template to form a local double strand; and moving the droplet to the second hot zone to synthesize a nucleic acid strand complementary to the template. S3. Repeat the polymerase chain reaction cycle.

14. The method according to claim 13, characterized in that, The digital microfluidic device includes a calibration sensor and a temperature controller, the temperature controller being connected to both the temperature sensor and the calibration sensor; prior to step S1, it further includes: Determine whether it is the calibration stage; if so, perform calibration processing; otherwise, proceed to step S1. The correction process includes: A calibration sensor is disposed in at least one hot zone of the digital microfluidic chip; The temperature controller acquires the heat transfer body temperature collected by the temperature sensor and the hot zone temperature collected by the calibration sensor; calculates the difference between the heat transfer body temperature and the hot zone temperature, and stores the difference as a calibration value. Remove the calibration sensor from the digital microfluidic chip.

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