TWI395610B - Liquid filtering device and filtering method using the same - Google Patents

Description

Liquid filtering device and filtering method thereof

The present invention relates to a liquid filtration device and a filtration method therefor.

The blood is responsible for the important work of oxygen and energy transfer in the living body, and is one of the indispensable elements for the normal operation of the living system. Based on this, various blood-centered application technologies have been developed in the field of clinical treatment and medical examination. It is hoped that the cells or substances contained in the blood can be obtained/analyzed correctly and quickly to further solve the discomfort caused by the pain and improve. The quality of human life. Under this concept, blood separation or filtration technology, which is the basis of many advanced applications, has been regarded as one of the key development projects.

At present, it is known that techniques for separating blood cells and plasma can be mainly classified into four categories. The first type is a centrifugal technique, in which the blood cells are placed in a test tube through the characteristics of a large proportion of blood cells, and the centrifugal force generated by the high-speed rotation is achieved to achieve the goal of separating blood cells from plasma. However, because the density and deposition rate of some blood cells are very close to, or even overlapping with, the plasma components, centrifugation techniques do not provide the required purity for certain applications. Moreover, this technology usually consumes a large amount of samples and medicines, and the processing takes a long time, and the overall cost is high.

The second principle is based on the dielectrophoretic force principle, combined with the micro-electromechanical process, providing a non-uniform alternating electric field with special instruments and equipment, and the separation between the two is caused by the different conductivity and dielectric constant between the blood cells and the plasma. However, this technology is still limited by the complexity of the steps and the expensive equipment required, and the application range is slightly narrow.

The non-contact high-wavelength laser system has developed a new technology in recent years, which uses a light source in the opposite direction to form a stable energy trap to clamp tiny particles. Although, the current doctrine theory believes that the use of such a tool method for separating blood will have the advantages of non-contact, non-invasive, etc., so that non-contact high-wavelength lasers are very much expected in this field, but the actual It is still difficult to overcome the problem of excessive equipment cost in industrial application, and it is quite difficult to carry out the exhibition.

The deep filtration system is more commonly used in the four techniques. By driving the blood, it flows through the multilayer film structure in a vertical direction, so that solid substances such as blood cells are trapped on the surface of the film. However, the biggest problem with this technique is the formation of filter cake on the surface of the film, especially as the amount of blood introduced increases, the thickness of the filter cake will inevitably increase, so that it must be rinsed and removed every time it is used, which is quite expensive. More manpower. In addition, more importantly, deep filtration tends to exert greater pressure on blood cells in the blood, causing hemolysis during the filtration process, resulting in failure of the separation operation.

In summary, it is obvious that the technique of separating blood cells to obtain plasma is inevitably subject to problems such as large sample consumption, expensive instrument equipment, inconsistent application cost, long operation time, and/or cumbersome process steps. Therefore, how to provide a device with low cost, The liquid filtering device with simple structure not only has a rapid reaction, but also requires a small amount of samples, and the operation is economical, and more importantly, it can effectively prevent the formation of filter cake and the phenomenon of hemolysis, which has become an important issue.

In view of the above problems, the object of the present invention is to provide a liquid filtering device which is low in cost and simple in structure, and which not only has a rapid reaction, but also requires a small amount of sample, and the operation is economical, and more importantly, it can effectively prevent the formation of filter cake. And hemolysis occurs.

To achieve the above object, a device for filtering a liquid according to the present invention comprises a first-class track and a filter film. The runners have excellent entrances and first class exits. The filter membrane has a plurality of pores. Wherein, the flow channel is stacked on the filter film, and the liquid contacts the filter film when flowing through the flow channel. In an embodiment of the invention, the liquid system flows substantially parallel through the filter membrane.

In one embodiment of the invention, the device is a microchip. Wherein, the liquid system is blood, and the liquid is filtered through the device to obtain a plasma.

In the embodiment of the invention, the flow channel is spiral or spiral.

In the embodiment of the invention, the pores have a pore size ranging from 1 micrometer to 50 micrometers. In an embodiment of the invention, the apertures of the holes are preferably 1 micron.

In an embodiment of the invention, the filter film has a first surface and a second surface. Wherein, the first surface has a plurality of curved surfaces, and the holes are disposed between the curved surfaces. The second surface corresponds to the holes having a plurality of recessed regions.

In an embodiment of the invention, the device further includes a cover housing. The flow channel and the filter film are accommodated in the covering case, and the flow inlet and the outflow port of the flow channel are exposed on one surface of the covering case. Wherein, the device further comprises a collecting trough. The collecting tank is placed on the covering shell, and the corresponding flow channel is disposed on the other side of the filtering film. The flow channel and the collecting tank communicate with each other through a hole of the filter film.

In an embodiment of the invention, the cladding housing has an upper flow channel portion and a lower collection portion. The flow channel is disposed in the upper flow channel portion, the collection groove is disposed in the lower collection portion, and the filter film is sandwiched between the flow channel and the collection groove.

In an embodiment of the invention, the device further includes an encapsulation portion. The encapsulation portion covers at least a portion of the cladding housing.

In an embodiment of the invention, the apparatus further includes a drive unit. The driving unit is connected to the flow path, and the driving liquid moves relative to the filtering film.

To achieve the above object, a liquid filtration method according to the present invention is obtained by introducing a liquid into a device according to the present invention and collecting the liquid through a portion of the filtration film. In an embodiment of the invention, the liquid system is blood and the portion of the liquid that passes through the filter membrane is plasma.

In one embodiment of the invention, the liquid system is continuously input to the device.

According to the above, the device according to the present invention and the filtering method thereof can be matched with the structure of the filter film through the flow channel, so that the target liquid can contact the filter film when flowing through the flow channel, and the micropores on the filter film are filtered. The liquid component in the target liquid is passed, and the solid substance is trapped to achieve the purpose of filtration separation, so it can be suitably used for a liquid containing suspended particles such as blood. More importantly, since the structure of the apparatus of the present invention allows the liquid to continuously flow in a state of parallel filtering of the film, in accordance with the sweeping principle, a corresponding shear stress can be generated in the flow path. Thus, when applied to, for example, filtering blood, it is effective in reducing the problem of filter cake formation, avoiding hole clogging and hemolysis, and is a blood separation device which is highly reliable and does not require frequent maintenance.

Compared with the prior art, the present invention is not only simple in structure, but also easy in process, and can be widely applied to liquid filtration containing suspended substances. In addition, the device according to the present invention is easier to produce in the form of a bio-wafer, which not only has the advantage of convenient transportation, but also requires less sample consumption per operation, and is advantageous for use in various grades of medical institutions or research units. In terms of time cost, the apparatus of the present invention only needs to select a matching filter film, and then simply input the liquid, and the result can be quickly obtained without complicated processing, thereby avoiding, for example, excessive lengthy process of the traditional blood separation process. The problem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid filtering device and a filtering method thereof according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

1 is a schematic view of a liquid filtering device according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the liquid filtering device shown in FIG. 1. Referring to FIG. 1, a device 1 according to the present embodiment is for filtering a liquid, and the liquid system is, for example, a flowable substance containing suspended particles, particles or other small solid matter. Here, the liquid system filtered by the apparatus 1 of the present embodiment is exemplified by whole blood or blood containing blood cells in which red blood cells collectively referred to as blood cells, various white blood cells and/or platelets are suspended. In addition, it should be particularly noted that the term "filtering" as used in this embodiment means passing the existing holes to specify the suspended particles, particles or other small solid materials in the liquid as it passes through the size. The limiting factor is stagnant or trapped at one end of the hole and separated from the liquid component that circulates to the other end of the hole. In addition, the filtration referred to in the present embodiment is not limited to complete separation, but covers errors that can be allowed due to manufacturing defects, a few special conditions, or a doctrine.

According to the foregoing definition, the device 1 of the present embodiment can be used, for example, to stagnant or trap blood cells including red blood cells, various white blood cells, and/or platelets at one end of a hole, and a blood cell-free blood portion at the other end of the access hole ( That is, plasma) is separated. Of course, in other embodiments of the present invention, the liquid filtering device 1 can also be used to filter an aqueous solution in which colloidal particles are suspended, such as an aqueous solution containing a pharmaceutical composition, and the present invention is not limited thereto.

Referring to FIG. 1 and FIG. 2 simultaneously, in the embodiment, the apparatus 1 for liquid filtration may be a micro device, such as a micro biochip, which has a thin rectangular parallelepiped appearance. In terms of the detailed structure, the apparatus 1 includes a cladding housing 11, a flow path 12, a collection tank 13, and a filter film 14. The cover case 11 can further have an upper flow path portion 111 and a lower collection portion 112. The upper flow path portion 111 and the lower collection portion 112 may be two pieces integrally formed or separated, and the sizes thereof may be the same or different. In the present embodiment, the upper flow path portion 111 and the lower collecting portion 112 are two separate parts, but the length, width and height are respectively 4 cm, 2.5 cm and 0.5 cm. After the upper flow path portion 111 and the lower collecting portion 112 are formed, the coating case 11 is formed by sealing and sealing. Of course, in addition to the above implementations, the size of the two can also be adjusted as required by the application, not a limitation.

The material of the cladding case 11 and the upper flow channel portion 111 and the lower collecting portion 112 may be, for example, polymethylmethacrylate (PMMA), poly-dimethylsiloxane (PDMS), epoxy. Epoxy, metal or glass. Of course, other polymer materials with better mechanical strength and high biocompatibility properties can also be used. In the present embodiment, the material of the coating casing 11 and its upper flow channel portion 111 and the lower collecting portion 112 is exemplified by polydimethyl methoxy oxane (PDMS), which is not cytotoxic and is suitable as a living biological sample. Contact material. In addition, polydimethyl oxa oxane also has good light transmittance and is easy to observe and other characteristics.

The flow path 12, the collection tank 13, and the filter film 14 are housed in the cladding casing 11. The flow channel 12 is disposed in the upper flow channel portion 111, the collection groove 13 is disposed in the lower collection portion 112, and the filter film 14 is interposed between the flow channel 12 and the collection channel 13. The flow channel 12 is a continuous liquid passage, and the bottom side is open, and the other upper side and the left and right sides are closed on three sides. Both ends of the flow path 12 are open to the outside, for example, an opening that is exposed in a circular shape on one surface 113 of the covering casing 11 in this embodiment. The openings of the flow channel 12 are respectively a liquid input flow inlet 121 and an output flow outlet 122, which can respectively be connected with a polytetrafluoroethene (PTFE) bridge joint, for example, so as to be connected with the injection syringe to avoid filtering. The liquid leaks when entering and exiting the flow path 12. The overall path of the flow channel 12 is not limited in shape. Here, it is a spiral or a spiral shape, which can form a long distance liquid passage within a certain area, which is beneficial to the liquid filtration operation. . However, in other embodiments, the flow channel 12 can also be in the form of a simple straight or serrated shape, depending on the filtration requirements and the components contained in the liquid, and can indeed separate the specified particles or solid materials from the liquid as a principle.

In the present embodiment, the flow path 12 is provided on the flow path portion 111 above the cladding casing 11 by means of potting. In detail, the polydimethyl methoxy alkane having a fluid colloidal property may be used to cover the master mold, and after the colloid is solidified, the portion formed by the polydimethyl siloxane is separated from the master mold to form a set. The flow path 12 covers the flow path portion 111 above the casing 11. Figure 3 is an enlarged schematic view of the flow path shown in Figure 2. Referring to FIG. 3, the flow path 12 is provided at the center of the upper flow path portion 111, and the entire flow path 12 (hereinafter referred to as a swept area) is substantially spiral or spiral. The sweeping area diameter d1 is about 0.8 cm. The channel 12 has a channel width d2 of about 50 microns and a channel structure height of about 100 microns. Of course, the above dimensions are not the limiting conditions of the present invention, but may be adjusted according to practical applications. In other embodiments, the channel width d2 of the flow channel 12 may be from about 50 to 500 microns, for example, 100 or 200 microns. The structural height of the flow channel 12 can be from about 10 to 500 microns, such as 20 or 200 microns. In addition, in the process of forming the flow path 12, the flow path portion 111 on the cladding casing 11 is formed into the outwardly opening inlet port 121 and the outflow port 122 through the design of, for example, a mold, where both are elongated tubes. (not shown in Figure 3).

Referring to FIG. 2 , the collecting groove 13 of the embodiment may be disposed in the lower collecting portion 112 according to the same manner as described above, and the corresponding flow channel 12 is disposed on the other side of the filtering film 14 . The collecting groove 13 may be a circular groove having a diameter of 0.8 cm and a structural height of 200 μm. Of course, the size of the collection trough 13 can also be adjusted, for example, by the amount of filtered liquid. In other embodiments, the height of the structure can be between 10 and 500 microns, for example, the height of the structure can be 20 or 200 microns.

In this embodiment, the centers of the sweeping zone, the collecting tank 13 and the filter film 14 may be substantially overlapped, for example, and the filter film 14 is interposed between the flow channel 12 and the collecting tank 13, in other words, the filtering film 14 is also It is interposed between the upper flow path portion 111 and the lower collection portion 112. The size and configuration of the filter film 14 are not particularly limited, and in principle, it is based on the principle of cooperating with the sweeping zone.

4a is a partially enlarged schematic view of the filter film shown in FIG. 2, and FIG. 4b is a schematic view of the filter film shown in FIG. 4a at a position along the line B-B. Referring to FIG. 4a and FIG. 4b simultaneously, in the present embodiment, the filter film 14 may be a circular film having a diameter of 1 cm and having a plurality of holes 141 thereon. The filter film 14 has a first surface 142 and a second surface 143, which are the upper surface and the lower surface of the filter film 14, respectively. In the present embodiment, the first surface 142 and the second surface 143 of the filter film 14 observed under the macroscopic view are both approximately flat surfaces without undulations (as shown in FIG. 2). However, referring to FIG. 4b, if further observed at a microscopic angle, the first surface 142 has a plurality of upwardly convex curved surfaces 144, and the holes 141 are disposed between the curved surfaces 144, and the second surface 143 corresponds to the holes 141. There are a plurality of recessed regions 145.

The above structure will be described in detail. Referring to FIG. 4a and FIG. 4b simultaneously, in the embodiment, the curved surface 144 can be, for example, a circular arc surface, and includes a top end and a bottom end, and the bottom end is disposed at a periphery of the hole 141. The recessed area 145 may be circular and have an area larger than the area of the hole 141. Further, the holes 141 are circular perforations that communicate with the first surface 142 to the second surface 143 of the filter film 14, and may have a diameter of, for example, 1 micrometer. However, in other embodiments of the present invention, the holes 141 may be of other shapes and/or sizes, for example, from 1 to 50 microns, and are in principle adjusted depending on the composition of the target solution and the size of the selected suspended particulate or solid material. For example, the blood cells in the whole blood are separated by filtration, and the diameter of the holes 141 is preferably 1 micrometer.

The filter film 14 may be an alloy material, which can be manufactured through several steps including a lithography process and electroforming. First, a substrate may be provided first, and then a photoresist layer is formed on one surface of the substrate. Subsequently, a plurality of photoresist patterns are formed on the photoresist layer and exposed on a part of the surface of the substrate. A photomask is disposed above the photoresist layer, wherein the photomask has a plurality of patterns corresponding to the photoresist patterns. Thereafter, exposure and development are performed to form a circular photoresist pattern as shown in this embodiment. An alloy layer is formed on the photoresist pattern and the substrate by electroforming. Finally, the alloy layer is separated from the photoresist pattern and the substrate to form the filter film 14 of the present embodiment.

Figure 5 is a schematic illustration of the apparatus of Figure 1 at a section line A-A. Referring to FIG. 5, in the embodiment, since the flow path 12 is substantially vertically stacked on the first surface 142 of the filter film 14, when the liquid L enters and flows through the flow path 12, it is inevitable. A portion of the film is in contact with the filter film 14 and flows over the filter film 14 in a manner substantially parallel to the filter film 14. The flow path 12 communicates with the collecting hole 13 through the hole 141 of the filtering film 14 by the configuration in which the bottom side is open, so that when the liquid L flows in the flow path 12, it is subjected to gravity. The curved surface 144 of a surface 141 flows to the hole 141 (the figure is still flat due to the giant angle, and the detailed structure can be referred to FIG. 4b), so that the liquid substance portion passes through the hole 141 smoothly, and the liquid L therein The solid matter containing, for example, particles or particles having a size larger than the size of the pores 141 is trapped by the pores 141 to achieve the effect of separation filtration.

It should be particularly noted that, by the structure of the apparatus 1 of the present invention, the liquid L can be made to conform to the principle of sweep filtration to generate parallel shear stress, thereby sweeping particles deposited on the first surface 142 of the filter film 14 during filtration or The solid matter having a particle size exceeding the size of the hole 141 prevents the filtration speed from being affected by the accumulation of the filtered material on the hole 141, resulting in an increase in the operational resistance. In order to produce better parallel shear stress and filtration effect, the flow rate of liquid L ranges from about 0.05 mL/min to 0.5 mL/min, and the filtration effect obtained at a higher flow rate is better, for example, 0.5 mL. /min.

Fig. 6 is a partially enlarged schematic view showing the flow path when whole blood is filtered by the apparatus of the first embodiment of the present invention to separate blood cells. Referring to FIG. 6 , especially when used for whole blood filtration to separate blood cells, blood BL can flow in the flow channel 12 in parallel with the filter film 14 according to the design of the present invention, and according to the above principle, not only white blood cells are used. WC, red blood cell RC and platelet PL are separated from plasma SR to complete the purpose of collecting plasma SR, and at the same time, it can effectively reduce the formation of filter cake and prevent occlusion and hemolysis.

Figure 7 is a schematic illustration of a device in accordance with a second embodiment of the present invention. Referring to FIG. 7, in the present embodiment, the structure and component composition of the apparatus 7 for liquid filtration are substantially the same as those described in the foregoing embodiment, and therefore, only the descriptions have been made below. The device 7 of the present embodiment further includes a driving unit 75 for providing power to drive the liquid to circulate in the flow channel 72. The driving unit 75 is connected to the inflow port 721 of the flow channel 72, preferably connected to the inflow port 721 through the Teflon bridge connector 76, and disposed on the upper side of the cladding case 71. The driving unit 75 can be, for example, a micro-injection pump, which can continuously push the liquid of the input device 7 from the external storage device (not shown) forward after starting, and maintain the inertia advancement, thereby forming a relative relationship with the filter film 74. mobile. According to this condition, the driving unit 75 can of course be other power-providing modules or components, such as an aspirator, a manually operated syringe or the like, or a gas pressure difference or at the inflow port 721 and the outflow port 722. A vacuum, a module or component that enables a liquid to be pushed.

In addition, it should be noted that the device according to the present invention can be additionally coated and protected by using a packaging technology. For example, in the third embodiment of the present invention, the device has substantially the same structure and component composition as the foregoing embodiment, and further includes A package. The encapsulating portion is made of a polymer material epoxy resin (Epoxy) and covers at least a part of the covering case, for example, covering the upper surface of the casing.

The present invention further discloses a filtration method for introducing a liquid into the apparatus of the present invention to separate particulates, particles or solid matter in a liquid, and collecting a portion passing through the filtration membrane through the liquid. For example, the filtration method of the present invention can be used to continuously input blood to filter blood cells in the blood and collect blood plasma portions after passing through the filtration membrane.

In order to verify the feasibility of the device of the present invention and the filtration method thereof, human blood is taken as an experimental example to explain the steps of operating the device of the present invention to separate blood cells in blood and collect plasma.

Experimental Example 1 Using the device of the present invention to filter human blood

The device of the invention made in the manner previously described is herein a microbiochip. First, 0.5 mL of human whole blood was taken from a 1 mL syringe. Whole blood is injected into the device of the present invention using a Teflon bridge connector to connect the syringe. Adjust the microinjection pump to maintain the flow rate in the range of 0.05 mL/min to 0.5 mL/min. The array flow rate used here can be set to 0.5 mL/min, 0.3 mL/min, 0.1 mL/min, 0.07 mL/min, and 0.05 mL/min. The injection can be completed within about 10 minutes of continuous input. The filtration result was observed by an optical microscope. As shown in Fig. 8, the blood flow path C was observed under a 10-fold microscope, and plasma and blood cells were separated by a filter film (as indicated by arrow D).

In summary, the device according to the present invention and the filtering method thereof can be matched with the structure of the filter film through the flow channel, so that the target liquid can contact the filter film when flowing through the flow channel, and the micropores on the filter film are filtered. The liquid component in the target liquid is passed, and the solid substance is trapped to achieve the purpose of filtration separation, so it can be suitably used for a liquid containing suspended particles such as blood. More importantly, since the structure of the apparatus of the present invention allows the liquid to continuously flow in a state of parallel filtering of the film, in accordance with the sweeping principle, a corresponding shear stress can be generated in the flow path. Thus, when applied to, for example, filtering blood, it is effective in reducing the problem of filter cake formation, avoiding hole clogging and hemolysis, and is a blood separation device which is highly reliable and does not require frequent maintenance.

Compared with the prior art, the present invention is not only simple in structure, but also easy in process, and can be widely applied to liquid filtration containing suspended substances. In addition, the device according to the present invention is easier to produce in the form of a bio-wafer, which not only has the advantage of convenient transportation, but also requires less sample consumption per operation, and is advantageous for use in various grades of medical institutions or research units. In terms of time cost, the apparatus of the present invention only needs to select a matching filter film, and then simply input the liquid, and the result can be quickly obtained without complicated processing, thereby avoiding, for example, excessive lengthy process of the traditional blood separation process. The problem.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1, 7. . . Device

11, 71. . . Covered housing

111. . . Upper runner

112. . . Lower collection department

113. . . surface

12, 72. . . Runner

121, 721. . . Inflow

122,722. . . Outflow

13. . . Collection tank

14, 74. . . Filter film

141. . . Hole

142. . . First surface

143. . . Second surface

144. . . Curved surface

145. . . Sag area

75. . . Drive unit

76. . . Teflon bridge connector

A-A, B-B. . . Section line

BL. . . blood

C. . . Runner

D. . . Arrow

D1. . . diameter

D2. . . width

PL. . . Platelet

RC. . . erythrocyte

SR. . . plasma

WC. . . leukocyte

1 is a schematic view of a liquid filtering device according to a first embodiment of the present invention;

Figure 2 is an exploded perspective view of the liquid filtering device shown in Figure 1;

Figure 3 is an enlarged schematic view of the flow path shown in Figure 2;

Figure 4a is a partially enlarged schematic view of the filter film shown in Figure 2;

Figure 4b is a schematic view of the filter film shown in Figure 4a at a position along the line B-B;

Figure 5 is a schematic view of the device of Figure 2 taken along the line A-A;

Figure 6 is a partially enlarged schematic view of the inside of the flow channel when the whole blood is filtered by the device of the first embodiment of the present invention to separate blood cells;

Figure 7 is a schematic illustration of a device in accordance with a second embodiment of the present invention;

Fig. 8 is a photographic view of the results of the first experimental example of the present invention observed under a 10x microscope.

1. . . Device

11. . . Covered housing

111. . . Upper runner

112. . . Lower collection department

113. . . surface

12. . . Runner

121. . . Inflow

122. . . Outflow

13. . . Collection tank

14. . . Filter film

Claims (16)

A liquid filtering device comprising: a first-class channel having a first-class inlet and a first-class outlet; a filter film having a plurality of holes; and a collecting groove, the corresponding flow channel being disposed on the other side of the filter film, wherein The flow channel is stacked on the filter film, and a liquid contacts the filter film when flowing through the flow channel, and the collection tank collects the liquid filtered through the filter film. The liquid filtering device of claim 1, further comprising: a covering shell, the flow channel and the filtering film are received in the covering shell, and the inflow port and the outflow port are exposed Covering one surface of the housing. The liquid filtering device of claim 2, wherein the collecting tank is housed in the covering casing. The liquid filtering device of claim 1, wherein the flow channel communicates with the collecting groove through the holes of the filtering film. The liquid filtering device according to claim 3, wherein the covering casing has an upper flow passage portion and a lower collecting portion, wherein the flow passage is disposed in the upper flow passage portion, and the collecting groove is disposed in the lower collecting portion. And the filter film is sandwiched between the flow channel and the collecting groove. The liquid filtering device of claim 2, further comprising: an encapsulating portion covering at least a portion of the covering casing. The liquid filtering device according to claim 1, wherein the flow path is spiral or spiral. The liquid filtering device of claim 1, wherein the filter film has a first surface and a second surface, the first surface has a plurality of curved surfaces, and the holes are disposed between the curved surfaces. And the second surface corresponds to a hole, and has a plurality of recessed regions. The liquid filtering device of claim 1, further comprising: a driving unit connected to the flow channel and driving the liquid to move relative to the filtering film. The liquid filtration device of claim 1, wherein the liquid system flows substantially in parallel through the filtration membrane. The liquid filtering device according to claim 1, which is a microchip. The liquid filtration device of claim 1, wherein the pores have a pore size ranging from 1 micrometer to 50 micrometers. The liquid filtration device according to claim 1, wherein the liquid system is blood, and the liquid is filtered through the liquid filtration device to obtain a plasma. A liquid filtration method by which a liquid is introduced into a liquid filtration device according to any one of claims 1 to 12, and a portion of the liquid passing through the filtration membrane is collected. The liquid filtration method of claim 14, wherein the liquid system is continuously input to the liquid filtration device. The liquid filtration method according to claim 14, wherein the liquid system is blood, and a portion of the liquid passing through the filtration membrane is plasma.