Microfluidic device and application method thereof

1 . A microfluidic device, comprising:

a first substrate and a second substrate that are oppositely arranged along a first direction;

a first storage box and a second storage box that are oppositely arranged along the first direction;

the first direction being a thickness direction of the microfluidic device, wherein:

the first storage box includes a first storage cavity and a first opening communicating with the first storage cavity, and the first substrate is fixed in the first storage cavity,

the second storage box includes a second storage cavity and a second opening communicating with the second storage cavity, and the second substrate is fixed in the second storage cavity, and

along the first direction, the first opening is arranged opposite to the second opening, the first storage box is nested with the second storage box, and a first channel is formed between the first substrate and the second substrate; and

liquid guide holes passing through the second substrate and the second storage box along the first direction and communicating with the first channel.

2 . The microfluidic device according to claim 1 , wherein the first storage box is integrally formed by injection molding, and the second storage box is integrally formed by injection molding.

3 . The microfluidic device according to claim 1 , wherein:

the first storage box includes a third storage cavity, the third storage cavity is between the first opening and the first storage cavity along the first direction, the third storage cavity communicates with the first opening and the first storage cavity respectively; and

an orthographic projection of a cavity bottom of the third storage cavity to a plane where the first substrate is located surrounds an orthographic projection of the first storage cavity to the plane where the first substrate is located, and at least part of the second storage box in the third storage cavity and nested with an inner side wall of the third storage cavity.

4 . The microfluidic device according to claim 3 , wherein the third storage cavity is arranged around the second storage box, an inner side wall of the third storage chamber includes at least one recessed part, and an empty groove is formed between an outer side wall of the second storage box and the at least one recessed part.

5 . The microfluidic device according to claim 4 , wherein:

the second storage box includes a boss connected to a side wall of the second storage cavity, the boss surrounds the second opening, and an orthographic projection of the boss to a plane where the second substrate at least partially overlaps an orthographic projection of the second storage cavity to the plane where the second substrate is located; and

the second substrate is fixed between the boss and a cavity bottom of the second storage cavity.

6 . The microfluidic device according to claim 1 , wherein a sealant is arranged between the second storage box and a bottom of the third storage cavity.

7 . The microfluidic device according to claim 1 , comprising:

a first area and a second area arranged on a periphery of the first area, the second area comprising a plurality of first conductive pads, wherein:

the first substrate includes a first substrate and a plurality of first electrodes arranged on a side of the first substrate facing the second substrate, the plurality of first electrodes is in the second area, and the plurality of first conductive pads is on the first substrate, and a first electrode is correspondingly connected to a first conductive pad through a signal line; and

a plurality of first pinholes, along the first direction, the plurality of first pinholes penetrating through the first storage box or the second storage box and exposing the plurality of first conductive pads.

8 . The microfluidic device according to claim 7 , wherein:

along the first direction, an orthographic projection of the plurality of first pinholes and the plurality of first conductive pads to the plane where the first substrate is located does not overlap an orthographic projection of the first channel to the plane where the first substrate is located.

9 . The microfluidic device according to claim 7 , wherein:

the second substrate includes a second substrate and a second electrode arranged on a side of the second substrate facing the first substrate, the second electrode is at least in the first area, the second electrode receives a fixed voltage signal; and

the second electrode is electrically connected to at least one first conductive pad on the first substrate through conductive glue.

10 . The microfluidic device according to claim 7 , wherein:

the second substrate includes a second substrate and a second electrode arranged on a side of the second substrate facing the first substrate, and the second electrode receives a fixed voltage signal; and

the microfluidic device includes at least one second pinhole, and along the first direction, the second pinhole penetrates through the first storage box or the second storage box and exposes at least part of the second electrode.

11 . The microfluidic device according to claim 1 , comprising a box forming area and a binding area on a first side of the box forming area, the second storage box being only in the box forming area, and the binding area comprising a plurality of conductive pads, wherein:

the first substrate includes a first substrate and a plurality of first electrodes arranged on a side of the first substrate facing the second substrate;

the second substrate includes a second substrate and a second electrode arranged on a side of the second substrate facing the first substrate; and

both the plurality of first electrodes and the second electrode are electrically connected to the plurality of conductive pads.

12 . The microfluidic device according to claim 11 , wherein:

the box forming area includes a first area and a second area surrounding the first area, the plurality of first electrodes and the second electrode are in the first area, and the second area is between the binding area and the first area on the first side of the box forming area; and

in the second area, a side wall of the second storage box facing a surface of the first substrate is fixed to the first substrate.

13 . The microfluidic device according to claim 12 , comprising a sealing gasket between the surface of the side wall of the second storage box facing the first substrate and the first substrate in the second area.

14 . The microfluidic device according to claim 1 , wherein the liquid guide holes include at least one liquid injection hole and at least one liquid outlet hole, at least one liquid injection hole and at least one liquid outlet hole are at two ends of the microfluidic device along a second direction extending a diagonal of the microfluidic device.

15 . The microfluidic substrate according to claim 1 , wherein the second storage box further comprises liquid guiding grooves communicating with the liquid guide holes and being on a side of a bottom surface of the second storage box away from the first storage box.

16 . The microfluidic device according to claim 15 , wherein an inner wall of the guide groove is in a shape of an inverted cone or a cylinder.

17 . The microfluidic device according to claim 1 , wherein:

the liquid guide holes include a first sub liquid guide hole and a second sub liquid guide hole communicated with the first sub liquid guide hole, the first sub liquid guide hole is in the second storage box, the first sub liquid guide hole is in the second storage box, and the second sub liquid guide hole is on the second substrate; and

at least part of an outer wall of the first sub liquid guide hole is nested with at least part of the inner wall of the second sub liquid guide hole.

18 . The microfluidic device according to claim 1 , wherein a cavity bottom of the second storage box is made of a transparent material, and the second substrate is a transparent substrate.