Digital microfluidic chip and digital microfluidic system

A digital microfluidic chip and a digital microfluidic system. The digital microfluidic chip comprises: an upper substrate and a lower substrate arranged opposite to each other; multiple driving circuits and multiple addressing circuits disposed between the lower substrate and the upper substrate; and a control circuit, electrically connected to the driving circuits and the addressing circuits. The control circuit is configured to apply, in a driving stage, a driving voltage to each driving circuit, such that a droplet is controlled to move inside a droplet accommodation space according to a set path, measure, in a detection stage, after a bias voltage is applied to each addressing circuit, a charge loss amount of each addressing circuit, and to determine the position of the droplet according to the charge loss amount. The charge loss amount of each addressing circuit is related to the intensity of received external light.

CROSS REFERENCE

This application is a US National Stage of International Application No. PCT/CN2019/097899, filed on Jul. 26, 2019, which claims priority to Chinese Patent Application No. 201810842202.9, filed with Chinese Patent Office on Jul. 27, 2018, entitled “Active Matrix Digital Microfluidic Chip”, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure relates to the field of biological detection and biochip technology, in particular to a digital microfluidic chip and system.

BACKGROUND

Digital microfluidic technology enables precise manipulation of the movement of droplets, to realize merging, separating and other operations of the droplets, and complete various biochemical reactions. Compared with general microfluidic technology, digital microfluidic technology enables manipulation of liquid at precision of each droplet, can complete a target reaction using a smaller volume of reagent and control the reaction rate and reaction progress more precisely.

SUMMARY

An embodiment of the present disclosure provides a digital microfluidic chip, including:

an upper substrate and a lower substrate disposed oppositely;

a first hydrophobic layer disposed on a side surface of the lower substrate facing the upper substrate;

a second hydrophobic layer disposed on a side surface of the upper substrate facing the lower substrate, with a space between the first hydrophobic layer and the second hydrophobic layer forming a droplet accommodation space; and

a plurality of drive circuits and a plurality of addressing circuits, located between the lower substrate and the upper substrate,

where one of the addressing circuits corresponds to at least one of the drive circuits.

Optionally, in an embodiment provided in the present disclosure, each of the plurality of drive circuits includes a driving electrode located between the lower substrate and the first hydrophobic layer, and a reference electrode located between the upper substrate and the second hydrophobic layer; the reference electrodes of the drive circuits are connected to each other to form an integrated structure; and

the digital microfluidic chip further includes a first insulating layer between a layer where the driving electrodes are located and the first hydrophobic layer, and a second insulating layer between a layer where the reference electrodes are located and the second hydrophobic layer.

Optionally, in an embodiment provided in the present disclosure, each of the addressing circuits includes a bottom electrode, a photoelectric conversion layer and a top electrode disposed in a stacked manner between the lower substrate and the first hydrophobic layer, where the bottom electrode is closer to the lower substrate than the top electrode, and the top electrode is a transparent electrode.

Optionally, in an embodiment provided in the present disclosure, a layer where the top electrode is located and the layer where the driving electrode is located are a same film layer.

Optionally, in an embodiment provided in the present disclosure, the top electrode is interconnected with an adjacent one of the driving electrodes to form an integrated structure.

Optionally, in an embodiment provided in the present disclosure, the layer where the top electrode is located is on a side facing the lower substrate, of the layer where the driving electrode is located; and an orthogonal projection of the top electrode on the lower substrate is at least partially covered by an orthographic projection of the driving electrode on the lower substrate.

Optionally, in an embodiment provided in the present disclosure, each of the plurality of drive circuits further includes a switching transistor between the lower substrate and the layer where the driving electrode is located, the switching transistor including a gate, a gate insulating layer, an active layer and a source-drain which are successively stacked on the lower substrate; and

a third insulating layer is provided between the switching transistor and the layer where the driving electrode is located, and a drain of the source-drain is connected to the driving electrode through a via hole running through the third insulating layer.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, the digital microfluidic chip further includes bias voltage signal lines electrically connected to the bottom electrodes; and

the bottom electrodes are disposed in a same layer as the source-drains, and the bias voltage signal lines are disposed in a same layer as the gates.

Correspondingly, an embodiment of the present disclosure further provides a digital microfluidic system, including the aforementioned digital microfluidic chip provided in an embodiment of the present disclosure and a control circuit;

where the control circuit is electrically connected to the drive circuits and the addressing circuits in the digital microfluidic chip, and the control circuit is configured to, in a driving stage, apply a driving voltage to each of the drive circuits to control a droplet to move according to a set path in the droplet storage space; and in a detection stage, detect the amount of charge loss of each of the addressing circuits after a bias voltage is applied to each of the addressing circuits, and determine the position of the droplet according to the amount of charge loss, where the amount of charge loss of each of the addressing circuits is related to the intensity of received external light.

Optionally, in an embodiment provided in the present disclosure, the control circuit is specifically configured to, in the driving stage, apply a driving voltage to the next drive circuit adjacent to the position of the droplet on the set moving path according to the determined position of the droplet so that the droplet moves along the set path.

Optionally, in an embodiment provided in the present disclosure, the control circuit includes a gate drive circuit and a data drive circuit;

the gates of the switching transistors in the digital microfluidic chip are electrically connected to the gate drive circuit through gate lines provided in the same layer, and sources of the source-drains of the switching transistors are electrically connected to the data drive circuit through data lines provided in the same layer, and the bias voltage signal lines are electrically connected to the gate drive circuit or the data drive circuit.

Correspondingly, an embodiment of the present disclosure further provides a driving method of the aforementioned digital microfluidic system, including:

in a driving stage, applying a driving voltage to each of the drive circuits to control a droplet to move according to a set path in the droplet storage space; and

in a detection stage, detecting the amount of charge loss of each of the addressing circuits after a bias voltage is applied to each of the addressing circuits, and determining the position of the droplet according to the amount of charge loss,

where the amount of charge loss of each of the addressing circuits is related to the intensity of received external light.

Optionally, in an embodiment provided in the present disclosure, the driving method specifically includes:

in the driving stage, applying a driving voltage to the next drive circuit adjacent to the position of the droplet on the set moving path according to the determined position of the droplet so that the droplet moves along the set path.

Correspondingly, the present disclosure further provides a digital microfluidic system, including:

a digital microfluidic chip including an upper substrate and a lower substrate disposed oppositely, a first hydrophobic layer located on a side surface of the lower substrate facing the upper substrate, a second hydrophobic layer located on a side surface of the upper substrate facing the lower substrate, and a plurality of drive circuits located between the lower substrate and the upper substrate, wherein a space between the first hydrophobic layer and the second hydrophobic layer forms a droplet accommodation space; and at least part of the plurality of drive circuits are set as monitoring sites; and

a Raman scattering detection device including a laser emitter, a receiver and an analysis circuit, wherein the laser emitter is configured to irradiate the monitoring sites one by one according to a preset timing; the receiver is configured to receive scattering spectra of the monitoring sites; and the analysis circuit is configured to determine whether a droplet is present at any of the monitoring sites according to the scattering spectra fed back by the receiver.

Correspondingly, the present disclosure further provides a positioning method of a digital microfluidic system, including:

controlling a droplet in a digital microfluidic chip to move on the set path;

before the droplet in the digital microfluidic chip is controlled to move to a detection site, irradiating a position to which the droplet is to move by a laser emitter in a Raman scattering detection device, and acquiring a Raman scattering spectrum by a receiver in the Raman scattering detection device; and

after the droplet in the digital microfluidic chip is controlled to move to the detection site, determining that the droplet has moved to the detection site when the Raman scattering spectrum acquired by the receiver has changed.

Optionally, in an embodiment provided in the present disclosure, controlling a droplet in a digital microfluidic chip to move on the set path specifically includes:

controlling different droplets in the digital microfluidic chip to move on at least two set paths that intersect each other; and

after determining that the droplets have moved to a detection site at an intersecting position and stayed for preset time, determining the droplets have reacted with each other at the intersecting position when Raman scattering spectra determined at detection sites at and after the intersecting position are different from Raman scattering spectra determined at detection sites before the intersecting position.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A related active matrix digital microfluidic chip generally includes a control circuit and drive circuits in a matrix arrangement. A driving voltage is applied to the drive circuits by the control circuit, so that a droplet moves according to a preset path. However, when the surfaces of the drive circuits are uneven or have impurities due to raw material, process, or environmental problems, a movement state of the droplet can be affected. As drive timing is determined in advance, a subsequent process will be influenced if there is no droplet position feedback mechanism. At present, a method for positioning a droplet mainly uses a sensor-based feedback control system, and it is common to determine a droplet position by using a change in an electrical signal. However, as the active matrix digital microfluidic chip is often configured to detect a biochemical reaction, the electrical signal may be very weak and a change in droplet composition will cause the electrical signal to change, so the method is not precise enough.

In view of the current problem of inaccurate droplet positioning, embodiments of the present disclosure provide a digital microfluidic chip and system. Specific implementations of the digital microfluidic chip and system provided in the embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. It should be noted that the embodiments described in the specification are only part of, rather than all of, the embodiments of the present disclosure; and the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. In addition, based on the embodiments in the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

A digital microfluidic chip provided in an embodiment of the present disclosure, as shown inFIGS.4-6, includes:

an upper substrate101and a lower substrate102disposed oppositely;

a first hydrophobic layer105disposed on a side surface of the lower substrate102facing the upper substrate101;

a second hydrophobic layer108disposed on a side surface of the upper substrate101facing the lower substrate102, with a space between the first hydrophobic layer105and the second hydrophobic layer108forming a droplet accommodation space109; and

a plurality of drive circuits001and a plurality of addressing circuits002, located between the lower substrate102and the upper substrate101, wherein one of the addressing circuits002corresponds to at least one of the drive circuits001.

Based on the same inventive concept, an embodiment of the present disclosure further provides a digital microfluidic system, as shown inFIGS.1and2, including the aforementioned digital microfluidic chip1provided in an embodiment of the present disclosure and a control circuit003.

The control circuit003is electrically connected to the drive circuits001and the addressing circuits002in the digital microfluidic chip1, and the control circuit003is configured to, in a driving stage, apply a driving voltage to each of the drive circuits001to control a droplet to move according to a set path in the droplet storage space109; and in a detection stage, detect the amount of charge loss of each of the addressing circuits002after a bias voltage is applied to each of the addressing circuits002, and determine the position of the droplet according to the amount of charge loss, where the amount of charge loss of each of the addressing circuits002is related to the intensity of received external light.

Specifically, in the aforementioned digital microfluidic chip and digital microfluidic system provided in embodiments of the present disclosure, due to refraction, scattering and other effects of the droplet on external light, the intensity of the external light received by the addressing circuit002corresponding to the position of the droplet is different from the intensity of the external light received by other addressing circuits002not covered by the droplet; and as the amount of charge loss of each addressing circuit002is related to the intensity of the external light received thereby, the position of the droplet can be determined by detecting the amount of charge loss of each addressing circuit002. The control circuit003can control the movement of the droplet, and thus the droplet position is accurately positioned while a function of driving the droplet to move is achieved by using the aforementioned digital microfluidic system provided in an embodiment of the present disclosure.

Specifically, in the aforementioned digital microfluidic chip and system provided in embodiments of the present disclosure, as shown inFIG.1for example, one addressing circuit002may correspond to one drive circuit001; that is, one addressing circuit002is arranged around each drive circuit001, and whether a droplet is present at the position of each drive circuit001is monitored by the addressing circuit002. Alternatively, one addressing circuit002may correspond to a plurality of drive circuits001; that is, a plurality of drive circuits001share one addressing circuit002around them, and whether a droplet is present at the position of any of a plurality of drive circuits001is monitoring by one addressing circuit002.

Further, for some reactions with complicated moving paths, once such phenomena as droplet stagnation occurs, a final experimental product or experimental result can be inevitably affected. Therefore, in the aforementioned digital microfluidic system provided in the embodiment of the present disclosure, the control circuit003can be specifically configured to, in the driving stage, apply a driving voltage to a next drive circuit001adjacent to the position of the droplet on the set moving path according to the determined position of the droplet so that the droplet moves along the set path. Specifically, the control circuit003can convert the amount of charge change of the addressing circuit002corresponding to the drive circuit001where the droplet is located into a driving voltage, and apply the driving voltage to the next drive circuit001adjacent to the drive circuit001where the droplet is located, on the set moving path so that the droplet moves along the set path. In this way, feedback control is achieved, and the influence of droplet stagnation on experimental result or experimental product is avoided.

FIG.3shows a principle diagram of feedback control achieved by the aforementioned digital microfluidic system provided in the embodiment of the present disclosure. It can be seen that the preset moving path of the droplet inFIG.3is from left to right; that is, the droplet gradually moves from left to right. At a moment the droplet moves to an area where the third drive circuit001from the left is located, the amount of charge loss of the addressing circuit002corresponding to the third drive circuit001from the left is converted into a driving voltage by the control circuit003, and the driving voltage is applied to the fourth drive circuit001from the left, so that the droplet moves from the area where the third drive circuit001from the left is located to the area where the fourth drive circuit001from the left is located, thus avoiding the influence of droplet stagnation by feedback control.

To better understand the technical solution of the present disclosure, a possible specific structure of the above-mentioned digital microfluidic chip and system provided in an embodiment of the present disclosure is described in detail below. It should be noted that the specific embodiment is only intended to describe the technical solution of the present disclosure, and does not limit the present disclosure.

FIG.4is a cross-sectional view of the aforementioned digital microfluidic chip according to the embodiment of the present disclosure along AA′ and BB′ ofFIG.2. Specifically, inFIG.4, on the left side of the dashed line is a cross-sectional view along AA′, and on the right side of the dotted line is a cross-sectional view along BB′.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIG.4, the drive circuit001can specifically include a driving electrode103located between the lower substrate102and the first hydrophobic layer105, and a reference electrode106located between the upper substrate101and the second hydrophobic layer108; and as the reference electrode106is generally applied with a fixed potential, the reference electrodes106of the drive circuits001can be connected to each other to form an integrated structure, which facilitates applying a fixed potential signal to the reference electrodes106of the drive circuits001, and is conducive to the fabrication of the reference electrodes106. The driving electrodes103of the drive circuits001are independent from each other, so that the control circuit003can achieve independent control of the drive circuits001by applying the driving voltage to the driving electrodes103one by one, and thereby can control the droplet movement.

Moreover, as shown inFIG.4, the digital microfluidic chip1can further include a first insulating layer104between the layer where the driving electrodes103are located and the first hydrophobic layer105, and a second insulating layer107between the layer where the reference electrodes106are located and the second hydrophobic layer108. Specifically, the arrangement of the first insulating layer104can achieve a function of isolating the driving electrodes103of the drive circuits001from the first hydrophobic layer105so that an electrical signal applied to the driving electrodes103does not affect the hydrophobic performance of the first hydrophobic layer105. On the other hand, the first insulating layer104can also function as a planarization layer to ensure that the first hydrophobic layer105can be formed on a relatively flat surface. Similarly, providing the second insulating layer107can achieve a function of isolating the reference electrodes106from the second hydrophobic layer108so that an electrical signal applied to the reference electrodes106does not affect the hydrophobic performance of the second hydrophobic layer108. On the one hand, the second insulating layer107can also function as a planarization layer to ensure that the second hydrophobic layer108can be formed on a relatively flat surface, so that the droplet accommodating space109for the droplet movement is formed between the flat first hydrophobic layer105and second hydrophobic layer108.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIG.4, the addressing circuit002can include a bottom electrode203, a photoelectric conversion layer202and a top electrode201disposed in a stacked manner between the lower substrate102and the first hydrophobic layer105, where the bottom electrode203is closer to the lower substrate102than the top electrode201. Specifically, to ensure that the photoelectric conversion layer202can receive external light, the top electrode201is preferably a semitransparent electrode. Further, to ensure that the photoelectric conversion layer202can fully experience the change in light intensity, the top electrode201is a transparent electrode, such as an indium tin oxide (ITO) electrode. In practical applications, the photoelectric conversion layer202has a PN junction or PIN junction structure or the like, and generally can be made of p-doped and n-doped amorphous silicon.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIGS.4and5, a layer where the top electrode201is located and the layer where the driving electrode103is located are a same film layer to simplify the process and reduce the manufacturing cost.

Further, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIG.4, the top electrode201can be interconnected with an adjacent driving electrode103to form an integrated structure; that is, the top electrode201of the address circuit002can be also used as the driving electrode103of the drive circuit001corresponding to the addressing circuit002, such that the addressing circuit002does not occupy too much space, and the distribution space for the driving electrodes103in the digital microfluidic chip1is guaranteed.

Alternatively, optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIG.6, the layer where the top electrode201is located may also be located on a side facing the lower substrate102, of the layer where the driving electrode103is located; and an orthogonal projection of the top electrode201on the lower substrate102is covered by an orthographic projection of the driving electrode103on the lower substrate102. Specifically, the driving electrode103may completely cover the top electrode201to ensure that the addressing circuit002does not occupy too much space, and the driving electrode may also partially cover the top electrode201, which is not limited herein.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIGS.1,2, and4to6, the drive circuit001can further include a switching transistor300between the lower substrate102and the layer where the driving electrode103is located; that is, the drive circuit001is of an active driving type; the switching transistor300can include a gate301, a gate insulating layer302, an active layer303and a source-drain304which are successively stacked on the lower substrate102; and specifically, the positions of the gate301and the active layer303may also be interchanged, which is not limited herein. A third insulating layer305is generally provided between the switching transistor300and the layer where the driving electrode103is located, and a drain304aof the source-drain304is connected to the driving electrode103through a via hole running through the third insulating layer305.

Optionally, in the aforementioned digital microfluidic chip provided in the embodiment of the present disclosure, as shown inFIGS.1,2, and4to6, the digital microfluidic chip1can further include bias voltage signal lines033electrically connected to the bottom electrode203; and

the bottom electrodes203can be disposed in a same layer as the source-drains304, and the bias voltage signal lines033can be disposed in a same layer as the gates301to reduce the number of film layers. Specifically, the bottom electrodes203can be connected to the bias voltages line033through via holes running through the gate insulating layers302.

Optionally, in the aforementioned digital microfluidic system provided by the embodiment of the present disclosure, as shown inFIG.1, the control circuit003can include a gate drive circuit031and a data drive circuit032; and the control circuit003may be integrated inside the digital microfluidic chip1, and may also be provided separately, which is not limited herein. The gates301of the switching transistors300are electrically connected to the gate drive circuit031through gate lines301′ provided in the same layer, and sources304bof the source-drains304of the switching transistors300are electrically connected to the data drive circuit032through data lines304′ provided in the same layer, and the bias voltage signal lines033are electrically connected to the gate drive circuit031or the data drive circuit032.FIG.1illustrates a situation where the bias voltage signal line033is electrically connected to the data drive circuit032. In practical applications, a bias voltage can be applied to the bottom electrodes203of the addressing circuits002at the same time through the data drive circuit032or the gate drive circuit031via the bias voltage lines033. To facilitate the data drive circuit or the gate drive circuit applying the bias voltage to the bottom electrodes203at the same time, the bias voltage lines033connected respectively to the bottom electrodes203of the addressing circuits002are connected together. In addition, to simplify the process and reduce the manufacturing cost, a common electrode line can be also used as the bias voltage line033.

Specifically, when the top electrode201and the driving electrode103are independent from each other, the top electrode201can be electrically connected to the data drive circuit032through a read line034, and when the top electrode201and the driving electrode103are a same electrode, the data line304′ is also used as the read line034, so that the amount of charge loss of each addressing circuit002transmitted via the read line034can be read through the data drive circuit032.

It can be known from the above description that a main feature of the aforementioned digital microfluidic chip and system provided in the embodiments of the present disclosure is that the function of driving the droplet to move and the function of positioning the droplet (i.e. the addressing function) are integrated in a manufacturing process of an array substrate. Specifically, a transparent conductive material such as ITO is used as the top electrode201of the addressing circuit002and also as the driving electrode103of the drive circuit001, to finally form a cell array having both droplet driving and positioning functions. The timing of the digital microfluidic system includes a droplet driving period and a droplet detecting period. In the droplet driving period, the driving electrodes103are controlled by the switching transistors300to be charged and discharged in a certain order to cause the droplet to move. In the droplet detecting period, the same bias voltage is applied to the bottom electrodes203of the addressing circuits002, and when the droplet moves over some addressing circuits002, due to refraction, scattering and other effects of the droplet on external light, the intensity of the light received by the photoelectric conversion layers202in the addressing circuits002changes as compared with the addressing circuits002that are not covered by the droplet, and a real-time position and movement track of the droplet can be obtained by reading the amount of charge loss of each addressing circuit002through the data drive circuit. Further, a charge loss amount signal obtained is converted into a control signal of the next drive circuit001after operation and processing by the data drive circuit, and the droplet is further driven to move, thereby achieving feedback control. Therefore, for the aforementioned active matrix digital microfluidic chip provided in the embodiment of the present disclosure, on the one hand, it can achieve a more accurate droplet operation, and is conducive to precise manipulation of a biological detection reaction; on the other hand, the overall structure and the manufacturing process of the addressing circuit002are easy to achieve and the cost is low.

Based on the same inventive concept, the present disclosure further provides a driving method of the aforementioned digital microfluidic system, including:

in a driving stage, applying a driving voltage to each of the drive circuits to control a droplet to move according to a set path in the droplet storage space; and

in a detection stage, detecting the amount of charge loss of each of the addressing circuits after a bias voltage is applied to each of the addressing circuits, and determining the position of the droplet according to the amount of charge loss;

where the amount of charge loss of each of the addressing circuits is related to the intensity of received external light.

Optionally, the aforementioned driving method provided in the embodiment of the present disclosure specifically includes:

in the driving stage, applying a driving voltage to a next drive circuit adjacent to the position of the droplet on the set moving path according to the determined position of the droplet so that the droplet moves along the set path.

Based on the same inventive concept, an embodiment of the present disclosure provides another digital microfluidic system, as shown inFIG.7, including:

a digital microfluidic chip1, as shown inFIG.8, the digital microfluidic chip1including an upper substrate101and a lower substrate102disposed oppositely, a first hydrophobic layer105located on a side surface of the lower substrate102facing the upper substrate101, a second hydrophobic layer108located on a side surface of the upper substrate101facing the lower substrate102, and a plurality of drive circuits001located between the lower substrate102and the upper substrate101, where a space between the first hydrophobic layer105and the second hydrophobic layer108forms a droplet accommodation space109; at least part of the plurality of drive circuits001are set as monitoring sites; specifically, all of part of the drive circuits001can be set as monitoring sites, which is not limited herein; and

a Raman scattering detection device2, the Raman scattering detection device2including a laser emitter004, a receiver005and an analysis circuit006, where the laser emitter004is configured to irradiate the monitoring sites one by one according to a preset timing; the receiver005is configured to receive scattering spectra of the monitoring sites; and the analysis circuit006is configured to determine whether a droplet is present at any of the monitoring sites according to the scattering spectra fed back by the receiver005.

Specifically, the Raman scattering detection device2can achieve the function of moving between the monitoring sites with the assistance of a fixed-point moving device such as a robot arm. In the digital microfluidic system, one Raman scattering detection device2may be provided, or a plurality of Raman scattering detection devices2may be provided, which is not limited herein.

Optionally, as shown inFIG.8, the drive circuit001can specifically include a driving electrode103located between the lower substrate102and the first hydrophobic layer105, and a reference electrode106located between the upper substrate101and the second hydrophobic layer108, and a switching transistor between the lower substrate102and the layer where the driving electrode103is located; that is, the drive circuit001is of an active driving type; the switching transistor can include a gate301, a gate insulating layer302, an active layer303and a source-drain304which are successively stacked on the lower substrate102; and specifically, the positions of the gate301and the active layer303may also be interchanged, which is not limited herein. A third insulating layer305is generally provided between the switching transistor300and the layer where the driving electrode103is located, and a drain of the source-drain304is connected to the driving electrode103through a via hole running through the third insulating layer305. The digital microfluidic chip1can further include a first insulating layer104between the layer where the driving electrode103is located and the first hydrophobic layer105, and a second hydrophobic layer107between the layer where the reference electrode106is located and the second hydrophobic layer108.

As we all know, Raman scattering is a fast, non-destructive, and highly specific detection method. Its detection time can be as short as 1 second. Raman spectra of different substances are different, and are “fingerprint spectra” of molecules. Therefore, a Raman spectrum of a drive circuit001covered with the droplet is necessarily different from that of a drive circuit001not covered with the droplet. Thus, the laser emitter004is used to irradiate the drive circuits001, then a scattering spectrum is obtained by the receiver005, and the scattering spectrum is analyzed by the analysis circuit to achieve positioning of the droplet position.

Moreover, if two droplets react and a new substance is produced, a Raman spectrum of a drive circuit001with a single droplet staying thereon is necessarily different from that of a drive circuit001with two droplets staying thereon. By scattering spectrum detection, it can be determined whether a reaction has occurred; that is, a reaction product is detected.

In summary, the digital microfluidic system shown inFIG.7not only can control the droplet movement, and achieve the droplet positioning, but also can detect the reaction product, and it is low in cost, small in calculation amount, efficient and fast.

Based on the same inventive concept, an embodiment of the present disclosure provides a positioning method of the aforementioned digital microfluidic system, as shown inFIG.9, including the following steps:

S901: controlling a droplet in a digital microfluidic chip to move on the set path;

S902: before the droplet in the digital microfluidic chip is controlled to move to a detection site, irradiating a position to which the droplet is going to move by a laser emitter in a Raman scattering detection device, and acquiring a Raman scattering spectrum by a receiver in the Raman scattering detection device; and

S903: after the droplet in the digital microfluidic chip is controlled to move to the detection site, determining that the droplet has moved to the detection site when the Raman scattering spectrum acquired by the receiver has changed.

Specifically, Raman scattering is a fast, non-destructive, and highly specific detection method. Its detection time can be as short as 1 second. Raman spectra of different substances are different, and are “fingerprint spectra” of molecules. Therefore, a Raman spectrum of a drive circuit covered with the droplet is necessarily different from that of a drive circuit not covered with the droplet. Thus, the laser emitter is used to irradiate the drive circuits001, then a scattering spectrum is obtained by the receiver, and the scattering spectrum is analyzed by the analysis circuit, that is, the Raman spectrum of the detection site is monitored so that the droplet moving position can be detected to achieve positioning of the droplet position.

Specifically, as a digital microfluidic system is often configured to detect a biochemical reaction, using the aforementioned digital microfluidic system provided in the embodiment of the present disclosure can achieve detection of the reaction product in addition to controlling the droplet movement and positioning the droplet position. Further, in the aforementioned positioning method provided in the embodiment of the present disclosure, specifically, the aforementioned step S901of controlling a droplet in a digital microfluidic chip to move on the set path specifically includes: controlling different droplets in the digital microfluidic chip to move on at least two set paths that intersect each other; and

after determining that the droplets have moved to a detection site at an intersecting position and stayed for preset time, determining the droplets have reacted with each other at the intersecting position when Raman scattering spectra determined at detection sites at and after the intersecting position are different from Raman scattering spectra determined at detection sites before the intersecting position.

Specifically, the digital microfluidic system shown inFIG.7detecting the reaction of two droplets is used as an example. It can be seen that inFIG.7, a driving voltage is applied to drive circuits001on a first preset moving path and drive circuits001on a second preset moving path one by one, so that two droplets respectively enter a drive circuit001where an intersecting point d of a first preset moving path and a second preset moving path is located, from a port a and a port b, and the two droplets merge and stay for preset time on the drive circuit001where the intersection point d is located and then move to a port c; and in this process, the laser emitter004irradiates the drive circuits001according to a preset timing. As we all know, Raman scattering is a fast, non-destructive, and highly specific detection method. Its detection time can be as short as 1 second. Raman spectra of different substances are different, and are “fingerprint spectra” of molecules. Therefore, if two droplets react and a new substance is produced, a Raman spectrum of a drive circuit001with a single droplet staying thereon is necessarily different from that of a drive circuit001with two droplets staying thereon.

In summary, the digital microfluidic system shown inFIG.7not only can control the droplet movement, and achieve the droplet positioning, but also can detect the reaction product, and it is low in cost, small in calculation amount, efficient and fast.

It should be noted that relational terms such as first and second herein are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply there is any such actual relationship or order between the entities or operations.

Apparently, those skilled in the art can make changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, the present disclosure is also intended to encompass these changes and modifications if such changes and modifications of the present disclosure are within the scope of the claims of the present disclosure and equivalents thereof.