Micro-fluidic chip and cleaning detection system and method for detecting cleaning degree

Abstract

The invention provides a micro-fluidic chip and a cleaning detection system and method for detecting the cleaning degree, and the micro-fluidic chip comprises a chip main body which is internally provided with a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, a slot array for simulating skin pores, and a liquid outlet, the first liquid inlet and the second liquid inlet are communicated with the cleaning channel through a mixing channel, the cleaning channel covers the slotted hole array and is communicated with the slotted hole array, and the cleaning channel is communicated with the liquid outlet.

Description

Technical Field

[0001] The present disclosure relates to the field of microfluidics, and in particular, to a microfluidics chip and a cleaning detection system and method for detecting a degree of cleanliness. Background Art

[0002] Microfluidic chips refer to the integration of microchannels or microchambers into a chip laboratory of several square centimeters through micro-nano processing methods to simulate the functions and characteristics of the laboratory. By precisely manipulating the liquid in the microchannel, the microfluidic chip can provide a controllable microchannel or microchamber, providing a good research platform for drug release, texture property research, etc. At present, there are many microfluidic chip designs on the market that can simulate complex biological environments, such as vascular systems, tissue structures, and skin barriers, and are used in active fields including drug testing, disease model research, molecular detection, cell analysis, etc. However, there is no microfluidic chip used for skin cleansing testing in the prior art. Summary of the invention

[0003] In view of the above-mentioned problems existing in the prior art, the embodiments of the present disclosure at least provide a microfluidic chip and a cleaning detection system and method for detecting the degree of cleanliness, so as to provide a reliable, efficient, accurate and timely experimental platform and method for the cleaning effect of skin cleansers.

[0004] According to a first aspect of an embodiment of the present disclosure, a microfluidic chip is provided, comprising: a chip body, wherein a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, a slot array for simulating skin pores, and a liquid outlet are provided in the chip body, wherein the first liquid inlet and the second liquid inlet are connected to the cleaning channel through the mixing channel, the cleaning channel covers the slot array and is connected to the slot array, and the cleaning channel is connected to the liquid outlet.

[0005] According to an embodiment of the present disclosure, the chip body includes a first chip and a second chip arranged opposite to each other, the first chip has a first surface, and the second chip has a second surface facing the first surface; the cleaning channel is recessed on the first surface, and the slot array is recessed on the second surface; the first surface is tightly fitted to the second surface so that the cleaning channel covers the slot array.

[0006] According to an embodiment of the present disclosure, the mixing channel is recessed on the first surface, and the second surface covers the mixing channel; the first liquid inlet, the second liquid inlet and the liquid outlet are arranged on the first chip, and the liquid outlet passes through the first chip in a direction perpendicular to the first surface.

[0007] According to an embodiment of the present disclosure, the microfluidic chip also includes: a clamping assembly, which is configured to clamp the chip body from opposite sides of the chip body and detachably connect the first chip with the second chip so that the first surface of the first chip and the second surface of the second chip are tightly fitted.

[0008] According to an embodiment of the present disclosure, the clamping assembly includes a first clamping plate and a second clamping plate respectively arranged on opposite sides of the chip body, and a connector that detachably connects the first clamping plate, the first chip, the second chip and the second clamping plate.

[0009] According to an embodiment of the present disclosure, the first clamp is located on the side of the first chip facing away from the second chip, and the first clamp has an open space open to the first chip, and the orthographic projection of the open space in a direction perpendicular to the first surface at least covers the cleaning channel and the mixing channel.

[0010] According to an embodiment of the present disclosure, the mixing channel extends in a bent manner in a plurality of different directions; and / or the mixing channel has a plurality of corners arranged at intervals in the direction in which it extends, and each of the corners is a sharp angle.

[0011] According to an embodiment of the present disclosure, the cross-sectional dimension of the mixing channel is 120-170 μm in width parallel to the first surface; and the height of the mixing channel perpendicular to the first surface is 80-120 μm.

[0012] According to an embodiment of the present disclosure, the cleaning channel and the slot array correspond to and are connected in the thickness direction of the chip body, and the depth of the cleaning channel in the thickness direction is 3 to 5 times the depth of each slot of the slot array in the thickness direction.

[0013] According to an embodiment of the present disclosure, the aperture of the slot is 80-150 μm.

[0014] According to an embodiment of the present disclosure, the chip body is prepared by a photolithography process and has skin-mimicking viscoelasticity.

[0015] A second aspect of an embodiment of the present disclosure provides a cleaning detection system for detecting the degree of cleanliness, comprising: the microfluidic chip provided by an embodiment of the present disclosure; an image acquisition device for acquiring an image of the slot array; and an image processing device for acquiring the grayscale of the image.

[0016] According to an embodiment of the present disclosure, the image acquisition device is a microscope.

[0017] According to a third aspect of an embodiment of the present disclosure, a cleaning detection method for detecting the degree of cleaning is provided, which is used to detect the cleaning effect of a cleaning agent on grease in skin pores based on a cleaning detection system of an embodiment of the present disclosure, and the method comprises: injecting a cleaning agent and a diluent into the chip body through a first liquid inlet and a second liquid inlet respectively, the cleaning agent and the diluent are mixed in the mixing channel and then flow into the cleaning channel, and in the process of flowing through the cleaning channel, the grease in each slot of the slot array is flushed, and then the grease is carried out out of the liquid outlet; images of the slot array at multiple different times during the flushing process are acquired by the image acquisition device; each of the images is processed by the image processing device to acquire the grayscale of each of the images; based on the grayscale of each of the images, the remaining amount of grease in the slots of the slot array at the multiple different times is determined.

[0018] According to an embodiment of the present disclosure, the method further includes: determining the average grayscale of at least part of the slots of the slot array at each moment based on the grayscale of each of the images; and establishing a relationship between the grayscale and the remaining amount of grease based on the average grayscale of the slots and the remaining amount of grease at the multiple different moments.

[0019] According to an embodiment of the present disclosure, the grease is an artificial simulated sebum stain; the relationship is: Grey=98.91x+30.06, wherein Grey is the average grayscale of the slot, and x is the remaining amount of grease in the slot.

[0020] The microfluidic chip provided in the embodiments of the present disclosure comprises at least a chip body. The first liquid inlet, the second liquid inlet and the mixing channel of the chip body can be used for diluting and mixing the cleaning liquid. The slot array simulates the skin pore structure. The cleaning channel covers the slot array and is connected to the slot array, thereby simulating the cleaning process of the cleaning liquid on the skin pore stains, so as to further realize the evaluation of the cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other purposes, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings. Obviously, the drawings described below are some embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0022] Figure 1 The schematic diagram shows the structure of the microfluidic chip in a disassembled state according to an embodiment of the present disclosure.

[0023] Figure 2A A top view of a microfluidic chip in an assembled state according to an embodiment of the present disclosure is schematically shown.

[0024] Figure 2B Schematically shows Figure 2A The cross-sectional view of the microfluidic chip along line BB.

[0025] Figure 2C Schematically shows Figure 2B A local enlarged view of point D of the microfluidic chip.

[0026] Figure 3 The simulation diagrams of the flow fields in three channel structures of different shapes are shown schematically.

[0027] Figure 4 A simulation diagram of the flow field in another mixing channel is schematically shown.

[0028] Figure 5 A simulation diagram of the flow field in another mixing channel is schematically shown.

[0029] Figure 6 The figure schematically shows the variation of the volume fraction of the detergent relative to the diluent in five channel structures of different shapes with the channel position.

[0030] Figure 7 The schematic diagram shows the comparison of the chip length occupied by five channels of different shapes when extending the same length.

[0031] Figure 8 A schematic diagram of a method for preparing a microfluidic chip using photolithography according to an example of the present disclosure is schematically shown.

[0032] Fig. 9 A schematic diagram schematically shows the variation of slot grayscale over time according to an example of the present disclosure.

[0033] Fig.10 A graph schematically shows the variation of the average grayscale of the slots over time according to an example of the present disclosure.

[0034] Fig.11 A standard curve diagram showing the variation of the gray scale of a slot hole with the amount of grease remaining in the slot according to an example of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages disclosed more obvious and understandable, the specific embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0036] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0037] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0038] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "having at least one of A, B, and C" should include but is not limited to having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, C, etc.). The terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features.

[0039] In an exemplary embodiment of the present disclosure, a microfluidic chip is provided. The microfluidic chip includes at least a chip body, which is used to simulate the cleaning process of the stains in the skin pores by the cleaning liquid. For example, the chip body can have at least a partial microporous structure to imitate the pore characteristics of the skin surface. Each "pore" can be filled with a substance that simulates skin secretions (such as sebum). The chip body can also have micro channels, which can be connected to each "pore" to accurately control the flow and pressure of the cleaning liquid to simulate different types of cleaning products.

[0040] In some embodiments, the chip body is provided with a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, a slot array for simulating skin pores, and a liquid outlet. It should be understood that the first liquid inlet, the second liquid inlet, and the liquid outlet are similar to the mixing channel and the cleaning channel, and also belong to the microchannel in the chip body. Among them, the first liquid inlet and the second liquid inlet are connected to the cleaning channel through the mixing channel. The cleaning channel covers the slot array and is connected to the slot array, and the cleaning channel is also connected to the liquid outlet. Among them, the first liquid inlet and the second liquid inlet can be used to receive a detergent and a diluent, respectively. Among them, the detergent and the diluent can be mixed into a cleaning liquid via the mixing channel. It should be understood that the first liquid inlet and the second liquid inlet can also be used to receive different components of the detergent, respectively, so as to be mixed into a cleaning liquid using the mixing channel. The cleaning channel is connected to the mixing channel so that the mixed cleaning liquid can enter the slot array and clean the material to be cleaned in the slot array. It should be understood that the present application does not limit the specific number of liquid inlets, and two or more liquid inlets can be set as needed.

[0041] It should be understood that the area of ​​the cleaning channel can be larger than the area of ​​the slot array to achieve sufficient contact between the cleaning liquid and the slots. The chip body also has a liquid outlet to allow the cleaning liquid to flow out of the liquid outlet. In an embodiment of the present disclosure, the slot array used to simulate skin pores has a size structure comparable to that of human skin. Optionally, the aperture of the slot is comparable to the aperture of the skin pores, for example, it can be 50 to 120 μm. For ease of testing and observation, the aperture of each slot in the slot array can be appropriately larger than the skin pores, for example, it can be 80 to 150 μm. In one example, the slot array can be composed of an array of 10*10 slots with a distance of 500 μm and a diameter of 100 μm.

[0042] In one example, the chip body can be integral. For example, the chip body can be integrally formed by 3D printing or other techniques to form a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, and a liquid outlet that are connected and arranged, and has a slot array that is connected and arranged to be covered by the cleaning channel.

[0043] In another example, the chip body can also be split, for example, the chip body can include at least two chips, wherein the first liquid inlet, the second liquid inlet, the mixing channel and the cleaning channel are connected and arranged on one chip, the slot array is arranged on another chip, and the cleaning channel corresponds to the area where the slot array is located, so that the cleaning liquid can flow through the slot array to clean the stains in the slot array.

[0044] Figure 1 The schematic diagram shows a structure of a microfluidic chip in a disassembled state according to an embodiment of the present disclosure. Figure 2A The schematic diagram shows a top view of the microfluidic chip in the assembled state. Figure 2B Schematically shows Figure 2A The cross-sectional view of the microfluidic chip along line BB. Figure 2C Schematically shows Figure 2B A partial enlarged view of the microfluidic chip at D. Figure 1 to Figure 2C As shown, the first chip 2 and the second chip 3 arranged opposite to each other constitute a chip body. The first chip 2 has a first surface, and the second chip 3 has a second surface 311 facing the first surface 211. The areas of the first surface 211 and the second surface 311 are respectively the same as the cross-sectional areas of the first chip 2 and the second chip 3. Figure 2B As shown in the example, the first surface 211 may be the lower surface of the first chip 2 , the second surface 311 may be the upper surface of the second chip 3 , and the first surface 211 and the second surface 311 face each other.

[0045] The cleaning channel 22 is recessed on the first surface 211, and the slot array I is recessed on the second surface 311. Figure 1 It can be seen that the cleaning channel 22 has an area larger than the slot array I. When the microfluidic chip is used, the first surface 211 and the second surface 311 fit tightly together so that the cleaning channel 22 covers the entire slot array I. The slot array I includes a plurality of slots 31, and each slot 31 is used to simulate a pore of the skin.

[0046] Further, from Figure 1 It can also be seen that the mixing channel 23 is recessed on the first surface 211 of the first chip 2. In the embodiment of the present disclosure, the mixing channel 23 is used to fully mix the cleaning liquid components from the first liquid inlet 24 and the second liquid inlet 25. The mixing channel 23 can be a groove structure.

[0047] In some embodiments, the first liquid inlet 24 , the second liquid inlet 25 and the mixing channel 23 may be disposed through the first chip 2 in a direction perpendicular to the first surface 211 .

[0048] In other embodiments, the first liquid inlet 24, the second liquid inlet 25 and the mixing channel 23 may also be arranged in a non-through manner on the first chip 2, and at least be opened in a groove shape on the first surface 211. Preferably, the depth of the mixing channel 23 is greater than or equal to the depth of the first liquid inlet 24 and the second liquid inlet 25. The second surface covers the mixing channel 23, so that the cleaning liquid can flow through the mixing channel 23 between the first surface 211 and the second surface 311 without leakage.

[0049] Combination Figure 1 and Figure 2CThe first liquid inlet 24 , the second liquid inlet 25 and the liquid outlet 21 are arranged on the first chip 2 , and the liquid outlet 21 penetrates the first chip 2 in a direction perpendicular to the first surface 211 , so that liquid can flow out from the liquid outlet 21 .

[0050] In an embodiment of the present disclosure, the microfluidic chip further comprises a clamping assembly which can be configured to clamp the chip body from opposite sides of the chip body and detachably connect the first chip to the second chip so that the first surface of the first chip and the second surface of the second chip fit closely.

[0051] Exemplarily, a clamping assembly with a magnetic suction design, a snap-lock clamping assembly, a screw-fastened clamping assembly, and the like can be used. For example, clamping sheets made of magnetic materials are provided on opposite sides of the chip body, one of which is a permanent magnet and the other is a magnetizable metal sheet. When the first chip is aligned with the second chip, the two chips are tightly fitted by magnetic attraction. Threaded holes can also be provided on both sides of the chip body, and the first chip and the second chip are brought into close contact by screwing in a spiral clamp and gradually applying pressure. Complementary snap-on structures can also be designed on both sides of the chip body, for example, they can include a raised snap-on head and a corresponding snap-on groove. When the first chip is aligned with the second chip and pressed, the snap-on head automatically snaps into the snap-on groove to form a stable connection.

[0052] Continue to refer Figure 1 In the example disclosed herein, the clamping assembly includes a first clamping plate 1 and a second clamping plate 4 respectively disposed on opposite sides of the chip body, and a connector (not shown in the figure) that detachably connects the first clamping plate 1, the first chip 2, the second chip 3, and the second clamping plate 4. When the connector is tightened, the first surface 211 of the first chip 2 and the second surface 311 of the second chip 3 fit closely. For example, the connector may include a bolt and a nut, and the bolt may sequentially pass through the through holes on the first clamping plate 1, the first chip 2, the second chip 3, and the second clamping plate 4, and be tightened by the nut to achieve a detachable connection.

[0053] exist Figure 1-2C In the embodiment, the first clamping plate 1 is located on the side of the first chip 2 facing away from the second chip 3, and the first clamping plate 1 has an open space 26 facing the first chip 2. The orthographic projection of the open space 26 in the direction perpendicular to the first surface at least covers the cleaning channel 22 and the mixing channel 23, so as to reduce the pressure of the first clamping plate 1 on the first chip 2, reduce the risk of chip damage, and prevent the cleaning channel 22 from being over-extruded to affect the smooth flow of the cleaning liquid in the cleaning channel 22 and the cleaning effect, thereby improving the fluid mechanics of the cleaning liquid in the cleaning channel and improving the cleaning effect. Figure 1As shown, the orthographic projection of the open space 26 in the direction perpendicular to the first surface can also cover the first liquid inlet 24 , the second liquid inlet 25 , the mixing channel 23 , and the liquid outlet 21 , so as to further reduce the pressure of the first clamping plate 1 on the first chip 2 .

[0054] The mixing channel of the embodiment of the present disclosure may be a non-straight channel structure, for example, it may be a serpentine channel, a micro-pillar array channel, a micro-turbine channel, etc.

[0055] In order to fully mix the cleaning agent and the dilution liquid in the mixing channel, the mixing channel is configured to extend in a curved manner in at least three different directions.

[0056] Three different embodiments of the mixing channel are provided below.

[0057] In the first embodiment, in order to generate turbulence when the cleaning agent and the diluent are mixed, and to enhance the collision of the liquids during mixing so as to achieve full fusion of the different components, the mixing channel can be designed as follows: Figure 1 The channel structure shown in the figure is Figure 1 The channel structure shown is called the first mixing channel.

[0058] Figure 1 The first mixing channel shown is a channel extending in at least three different directions, and has a plurality of corners arranged at intervals in the extending direction, each corner being a right angle. Thus, the cleaning liquid collides with each corner when passing through it, and the collision can make the mixture more uniform, thereby improving the cleaning ability of the mixed liquid.

[0059] exist Figure 1 In the example, the first mixing channel includes a plurality of sequentially connected and connected extension sections 231, each extension section 231 includes a first section extending toward the cleaning channel 22 (first direction), a second section extending from the end of the first section toward a direction perpendicular to the first section (second direction), a third section extending from the end of the second section toward a direction opposite to the extension direction of the first section and parallel to the extension direction of the first section (third direction), a fourth section extending from the end of the third section toward a direction opposite to the extension direction of the second section and parallel to the extension direction of the second section (fourth direction), a fifth section extending from the end of the fourth section toward the same direction as the extension direction of the third section, a sixth section extending from the end of the fifth section toward the same direction as the extension direction of the second section, and a seventh section extending from the end of the sixth section toward the same direction as the extension direction of the first section. The mixing channel of this structure can significantly improve the mixing uniformity. In order to qualitatively verify the mixing effect of the first mixing channel in the microfluidic chip of the first embodiment, a simulation comparative study was performed using COMSOL Multiphysics based on the theory of two-phase flow. The simulation comparison experiment constructed Figure 3 The three simulation models shown in the figure are as follows: the first one is a straight channel, the second one is a wavy channel, and the third one is a Figure 1 The first mixing channel 23 is shown. In the experiment, the first liquid inlet of the three models is the inlet of the diluent (such as water), and the second liquid inlet is the inlet of the detergent phase. The width and total length of the channels of the three simulation models are equal, and the mixing time of the liquids during simulation is also equal.

[0060] In order to conveniently display the mixing effect, black is used as the simulated color of water and yellow is used as the simulated color of detergent during simulation. The mixing effect of the three channels can be judged according to the colors at the outlets of the three channels.

[0061] like Figure 3 As shown in the figure, the total channel lengths of the simulation models of the three channels are equal. Figure 3 The color coordinate axis in represents the volume fraction of the detergent phase in the mixed solution. The gradient from black to yellow in the coordinate axis (i.e., from bottom to top) represents the gradual increase in the volume fraction of the detergent phase. The orange represents that the volume fraction of the detergent phase is 0.5. When the volume fraction of the detergent phase is 0.5, it means that the detergent phase and the water phase are mixed in a 1:1 ratio. It should be understood that the larger the proportion of the orange area, the closer the volume fraction of the detergent phase is to 0.5, and the more uniform the mixing.

[0062] Figure 3 The three color boxes in the figure are enlarged images of the outlets of the three channels. It can be clearly seen that the color at the outlet of the first mixing channel (i.e. Figure 3 The proportion of orange area in the leftmost color box in the middle is greater than the proportion of orange area in the color at the exit of the wavy channel (i.e. the middle color box) and the proportion of orange area in the color at the exit of the straight channel (i.e. the rightmost color box).

[0063] The above simulation results show that the volume fraction of the detergent phase at the outlet of the first mixing channel is closer to 0.5, and the mixing effect is significantly better than that of the wavy channel and the straight channel.

[0064] In the second embodiment, the mixing channel can be designed as follows Figure 4 The channel structure shown in the figure is Figure 4 The channel structure shown is called the second mixing channel. The second mixing channel can also be called a multi-hedge channel. Figure 4 It is a simulation structure of the second mixing channel, which not only shows the structure of the second mixing channel, but also shows the mixing effect of the second mixing channel on the detergent phase and water.

[0065] Figure 4The second mixing channel shown is a channel extending in three different directions, and has a plurality of corners arranged at intervals in the extending direction, each corner being a right angle. Thus, the cleaning liquid collides with each corner when passing through it, and the collision can make the mixture more uniform, thereby improving the cleaning ability of the mixed liquid.

[0066] exist Figure 4 In the example of , the second mixing channel includes at least two extension sections 232, the inlet end of each extension section 232 is connected to the first liquid inlet and the second liquid inlet, the outlet end of each extension section is connected to the cleaning channel, each extension section includes a first straight section 2321 extending along the first direction, a second straight section 2322 extending along the second direction, and a plurality of square sections 2323, at least part of the direction section extends along a third direction different from the first direction and the second direction, for example, Figure 4 In the example, a portion 2324 of the directional segment extends along a third direction opposite to the first direction; at least one of the plurality of square segments is disposed on the first straight segment or the second straight segment, such as Figure 4 The square section 2323 in the figure is arranged on the second straight section 2322, and at least one of the plurality of square sections is arranged on another square section, such as Figure 4 The smaller square section 2325 is arranged on the larger square section 2326. The mixing channel of this structure can significantly improve the mixing uniformity.

[0067] In a third embodiment, the mixing channel can be designed as follows Figure 5 The channel structure shown in the figure is Figure 5 The channel structure shown is called a third mixing channel, and the third mixing channel may also be called a vortex channel. Figure 5 It is a simulation structure of the third mixing channel, which not only shows the structure of the third mixing channel, but also shows the mixing effect of the third mixing channel on the detergent phase and water.

[0068] Figure 5 The third mixing channel shown is a channel extending in a curved manner in more than three different directions, whereby the cleaning liquid can be mixed more evenly when passing through the curved channel, thereby improving the cleaning ability of the mixed liquid.

[0069] exist Figure 5 In the example of , the third mixing channel includes a plurality of extension sections 233 connected and communicated in sequence, the plurality of extension sections 233 extend around different central spirals respectively, each extension section 233 extends inwardly from its respective inlet end toward its respective central spiral to its center, and then extends outwardly from its central spiral to its respective outlet end. Figure 5Taking the first extension section 233 in the example, the extension section 233 spirally extends inward from its inlet end 2331 toward its center 2332 to its center 2332, and then spirally extends outward from its center 2332 to its outlet end 2333. The mixing channel of this structure can significantly improve the mixing uniformity.

[0070] In order to qualitatively verify the mixing effect of the second and third mixing channels in the microfluidic chips of the second and third embodiments, a simulation comparison study was performed using COMSOL Multiphysics based on the theory of two-phase flow to simulate and compare the second and third mixing channels with the straight channel and the wavy channel (not shown). The simulation results also show that the volume fraction of the detergent phase at the outlet of the second and third mixing channels is closer to 0.5, and the mixing effect is significantly better than that of the wavy channel and the straight channel.

[0071] In order to quantitatively verify the mixing effect of the first, second and third mixing channels in the microfluidic chips of the first to third embodiments of the present invention, the inventors also drew a schematic diagram of the detergent volume fraction at the outlets of the first mixing channel, the second mixing channel, the third mixing channel, the wavy channel and the straight channel based on the simulation model described above, and used the volume fraction of the detergent phase as a quantitative evaluation index of the degree of mixing, and used the degree of proximity of the volume fraction of the detergent phase of each channel to 0.5 as a quantitative evaluation basis. The closer to 0.5, the better the mixing effect.

[0072] like Figure 6 As shown, the abscissa represents the longitudinal direction on the cross section of the channel outlet, the origin of the abscissa represents any point at the bottom end of the cross section of the channel outlet, the direction of the abscissa represents the direction from the bottom end to the top end of the cross section of the channel outlet, and the ordinate represents the volume fraction of the detergent phase. Figure 6 The middle dashed line is the ideal curve for complete mixing, representing a detergent phase volume fraction of 0.5.

[0073] Figure 6 The volume fraction curves of the detergent phase at the outlets of the first mixing channel, the second mixing channel, the third mixing channel, the wavy channel and the straight channel show that the curves of the first, second and third mixing channels are closest to the ideal curves, indicating that the mixing effects of the first, second and third mixing channels are significantly better than those of the wavy channel and the straight channel.

[0074] In addition to studying the mixing effect of the mixing channel structure, the inventors also conducted experimental research on the characteristics of the length of the mixing channel occupied by the chip. It can be understood that when the total length of the channel extension is the same, the smaller the length of the channel occupied by the chip, the more space is saved, which helps to reduce the chip volume.

[0075] Figure 7 The experimental results are shown by Figure 7It can be seen that when the total length of the channel extension is the same, the length of the chip occupied by the first, second and third mixing channels is significantly smaller than that of the straight channel and the wavy channel, which helps to reduce the chip volume.

[0076] According to an embodiment of the present disclosure, the cross-sectional dimensions of the mixing channel 23 may be smaller than the cross-sectional dimensions of the first liquid inlet and the second liquid inlet to increase the liquid flow rate and accelerate mixing. Optionally, the cross-sectional dimensions of the mixing channel 23 are 120 to 170 μm in width parallel to the first surface; and 80 to 120 μm in height perpendicular to the first surface.

[0077] According to an embodiment of the present disclosure, the cleaning channel 22 and the slot array 1 correspond to and communicate with each other in the thickness direction of the chip body. Figure 1 As shown in FIG. 2 , the cleaning channel 22 and the slot array I correspond to and are connected in a direction perpendicular to the first chip (or the second chip). The depth of the cleaning channel 22 in the thickness direction is 3 to 5 times the depth of each slot of the slot array I in the thickness direction, so as to better utilize the capillary force to guide the cleaning liquid into the slots, and to generate sufficient shear force when the cleaning liquid flows in the slot array area, ensuring that each slot can be fully cleaned. Optionally, the end face of the slot array I close to the cleaning channel 22 is 1200 μm away from the boundary of the cleaning channel 22 close to the slot array I, the boundary of the slot array I close to the liquid outlet 21 is 8500 μm away from the center of the liquid outlet, and the slot array I is located on the symmetry axis of the cleaning channel. In some embodiments, the slot array I corresponds to the central area of ​​the cleaning channel.

[0078] The microfluidic chip of the disclosed embodiment can be manufactured by a photolithography process, and the chip body has skin-like viscoelasticity.

[0079] Specifically, the embodiments of the present disclosure can simulate the real pore distribution through modeling, and then use high-precision processing to customize the mask plate, and finally prepare a chip with a similar skin pore structure through exposure, mold inversion, etc. Among them, polydimethylsiloxane, hydrogel, and polyurethane can be used as materials for microfluidic chips.

[0080] Figure 8 The schematic diagram of the method for preparing a microfluidic chip by photolithography according to an example of the present disclosure is schematically shown. Figure 8As shown, in the example disclosed in the present invention, polydimethylsiloxane (PDMS) is used as the material of the microfluidic chip. Among them, the S1 process represents the glue leveling, using a glue leveling machine to evenly coat 100 microns of photocurable glue on the clean silicon wafer surface. The S2 process represents exposure, placing ultraviolet curing light and photoresist on both sides of the mask respectively, and then using ultraviolet light to cure the photoresist. The S3 process represents development, using a developer to absorb the uncured photoresist part so that the mask pattern appears, and a protrusion similar to a pore structure is obtained. The S4 process represents casting, pouring the PDMS thermal curing agent on the chip and heating it at a constant temperature for a period of time. The S5 process represents mold inversion, and after the PDMS is cured, it is removed to obtain a depression with a pore structure similar to that of the pores.

[0081] The embodiments of the present disclosure also provide a cleaning detection system, comprising: the microfluidic chip provided by the embodiments of the present disclosure; an image acquisition device for acquiring an image of a slot array; and an image processing device for acquiring the grayscale of the image.

[0082] In the embodiments of the present disclosure, a microfluidic chip can be used to perform a cleaning experiment. An image acquisition device is used to acquire an image of the slot array at any time, and an image processing device is used to process the acquired image to characterize the grayscale of the image.

[0083] According to an embodiment of the present disclosure, the image acquisition device may be a microscope. An example is to use a camera carried by the microscope to capture an image of a sample under the microscope, convert the optical image into digital image data, and then use an image processing device to process the digital image data to obtain a grayscale value of the image;

[0084] In some embodiments, the image acquisition device and the image processing device may be integrated into one, for example, it may be a microscope equipped with a camera, and the camera is equipped with image processing software, and the image processing software can process the digital image data to obtain the grayscale value of the image.

[0085] The embodiment of the present disclosure also provides a cleaning detection method, which is used to detect the cleaning effect of a cleaning agent on the oil in the skin pores based on the cleaning detection system of the embodiment of the present disclosure. The cleaning detection method at least includes operations S601 to S604.

[0086] In operation S601, a cleaning agent and a diluent are injected into the chip body through the first liquid inlet and the second liquid inlet respectively. The cleaning agent and the diluent are mixed in the mixing channel and flow into the cleaning channel. In the process of flowing through the cleaning channel, the grease in each slot of the slot array is flushed and then the grease is carried out from the liquid outlet.

[0087] In operation S602, images of the slot array at multiple different moments during the washing process are acquired by an image acquisition device. For example, it can be preset to take pictures of the slot array at fixed time intervals to acquire images representing the state of the slot array at the current moment. Exemplary time intervals can be tens of seconds. For example, it can be set to take pictures at 40s, 80s, 120s, and 160s after the detergent and diluent are injected to acquire images of the slot array. Among them, each slot in the slot array can be photographed and an image can be acquired at the same moment, or an image with a sufficiently clear image can be taken of the entire slot array to identify the state of each slot in the image.

[0088] In operation S603, each image is processed by an image processing device to obtain a grayscale value of each image.

[0089] In operation S604, the amount of grease remaining in the slots of the slot array at a plurality of different moments is determined based on the grayscale of each image.

[0090] For example, after using a microscope equipped with a camera to obtain an image of the slot array or an individual image of each slot, these images can be processed by an image processing device to obtain the grayscale value of each slot. Since different amounts of grease will produce different degrees of light absorption or scattering under the irradiation of light, thereby affecting the grayscale value of the final image, the remaining amount of grease in the slot can be determined based on the grayscale value of the slot presented in the images taken at different times, and the cleaning effect of the cleaning liquid can be analyzed by the change in the remaining amount of grease.

[0091] Fig. 9 The schematic diagram of observing the change of the slot grayscale over time according to the example of the present disclosure is schematically shown. It shows the change of the grayscale of 5 selected slots over time. Fig. 9 It can be seen that the images are taken at a time interval of 40 seconds, and the gray value of each slot increases over time (color variable), indicating that the remaining amount of grease in the slot gradually decreases. Fig.10 A schematic diagram of a graph showing the average grayscale of a slot hole changing over time according to an example of the present disclosure is shown. Fig. 9 The same trend is shown in Figure 1: the average value of the average grayscale in the 5 selected slots decreases over time, indicating that the grease in the slots is gradually cleaned and reduced.

[0092] The cleaning detection method of the embodiment of the present disclosure may further include operations S605 to S606.

[0093] In operation S605, the average grayscale of at least part of the slots of the slot array at each moment is determined according to the grayscale of each image.

[0094] In operation S606, a relationship between the grayscale and the remaining amount of grease is established according to the average grayscale of the slots and the remaining amount of grease at a plurality of different moments.

[0095] The example method disclosed in the present invention can obtain the "remaining grease amount-grayscale" standard curve required for the grayscale analysis method by establishing the relationship between grayscale and remaining grease amount. Subsequently, the remaining grease amount can be directly obtained based on the measured grayscale using only the above standard curve.

[0096] Optionally, the grease is an artificial simulated sebum stain. In this example, the proportion of the artificial simulated grease mixture in the slot to the entire micropore slot is defined as the residual grease. Before the cleaning experiment begins, the grayscale value of the slot is measured, and then the grayscale value of the slot when the residual grease amount is a certain value during the experiment is measured. After the experiment is completed and the grayscale value is fully cleaned, the grayscale value is measured again. After fitting the measured grayscale values, a standard curve of the slot grayscale changing with the residual grease in the slot is obtained. Figure 8 shown.

[0097] exist Fig.11 In the figure, the relationship between grayscale and residual grease is:

[0098] Grey=98.91x+30.06

[0099] Among them, Grey is the average grayscale of the slot, and x is the remaining grease in the slot.

[0100] Among them, the correlation coefficient of the obtained curve is:

[0101] R 2 =0.9714,

[0102] It shows that the fitting equation has a fairly good correlation.

[0103] By establishing a standard curve of the change of the gray scale of the slot hole with the remaining grease in the slot, the cleaning effect of various cleaning agents on the grease in the slot hole can be detected in real time.

[0104] For example, when it is necessary to test the cleaning effect of a new cleaning agent on artificial simulated sebum stains, the cleaning detection system of the present invention can be used to obtain the corresponding grayscale, and then the grayscale can be directly substituted into the above equation to obtain the remaining amount of oil after cleaning, thereby achieving rapid detection of the cleaning effect.

[0105] Unless otherwise specifically stated, the numerical parameters in this specification and the appended claims are approximate values ​​and can be changed according to the desired properties obtained through the content of the present disclosure. Specifically, all numbers used in the specification and claims to express the content of the composition, reaction conditions, etc. should be understood to be modified by the term "about" in all cases. In general, the meaning of the expression is to include a change of ±10% in some embodiments, a change of ±5% in some embodiments, a change of ±1% in some embodiments, and a change of ±0.5% in some embodiments by a specific number.

[0106] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0107] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A microfluidic chip, characterized in that: include: A chip body, wherein a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, a slot array for simulating skin pores, and a liquid outlet are provided in the chip body, wherein the first liquid inlet and the second liquid inlet are connected to the cleaning channel through the mixing channel, the cleaning channel covers the slot array and is connected to the slot array, and the cleaning channel is connected to the liquid outlet.

2. The microfluidic chip according to claim 1, characterized in that: The chip body comprises a first chip and a second chip arranged opposite to each other, the first chip has a first surface, and the second chip has a second surface facing the first surface; The cleaning channel is recessed on the first surface, and the slot array is recessed on the second surface; The first surface is tightly fitted to the second surface so that the cleaning channel covers the slot array.

3. The microfluidic chip according to claim 2, characterized in that: The mixing channel is recessed on the first surface, and the second surface covers the mixing channel; The first liquid inlet, the second liquid inlet and the liquid outlet are arranged on the first chip, and the liquid outlet passes through the first chip in a direction perpendicular to the first surface.

4. The microfluidic chip according to claim 2, characterized in that: Also includes: The clamping assembly is configured to clamp the chip body from two opposite sides of the chip body and detachably connect the first chip and the second chip so that the first surface of the first chip and the second surface of the second chip are closely fitted.

5. The microfluidic chip according to claim 4, characterized in that: The clamping assembly includes a first clamping plate and a second clamping plate respectively arranged on opposite sides of the chip body, and a connecting member for detachably connecting the first clamping plate, the first chip, the second chip and the second clamping plate.

6. The microfluidic chip according to claim 5, characterized in that: The first clamping plate is located on a side of the first chip facing away from the second chip. The first clamping plate has an open space facing the first chip. The orthographic projection of the open space in a direction perpendicular to the first surface covers at least the cleaning channel and the mixing channel.

7. The microfluidic chip according to any one of claims 1 to 6, characterized in that: The mixing channel extends in a curved manner in at least three different directions.

8. The microfluidic chip according to claim 7, characterized in that: The mixing channel has a plurality of corners arranged at intervals in the extending direction thereof, and each of the corners is a sharp corner.

9. The microfluidic chip according to claim 8, characterized in that: The mixing channel includes a plurality of extension sections connected in sequence, each of the extension sections includes a first section extending in a first direction, a second section extending in a second direction, a third section extending in a third direction, and a fourth section extending in a fourth direction, the first direction is opposite to and parallel to the third direction, the second direction is opposite to and parallel to the fourth direction, and the first direction is perpendicular to the second direction.

10. The microfluidic chip according to claim 8, characterized in that: The mixing channel includes at least two extension sections, the inlet end of each extension section is connected to the first liquid inlet and the second liquid inlet, the outlet end of each extension section is connected to the cleaning channel, each extension section includes a first straight section extending along a first direction, a second straight section extending along a second direction, and a plurality of square sections, at least part of the direction sections extends along a third direction different from the first direction and the second direction, at least one of the plurality of square sections is arranged on the first straight section or the second straight section, and at least one of the plurality of square sections is arranged on another square section.

11. The microfluidic chip according to claim 8, characterized in that: The mixing channel includes a plurality of extension sections connected in sequence, wherein the plurality of extension sections extend around different central spirals respectively, and each of the extension sections extends inwardly from a respective inlet end toward a respective central spiral to the center, and then extends outwardly from the central spiral to a respective outlet end.

12. The microfluidic chip according to any one of claims 2 to 6, characterized in that: The width of the cross section of the mixing channel parallel to the first surface is 120-170 μm; the height of the mixing channel perpendicular to the first surface is 80-120 μm.

13. The microfluidic chip according to any one of claims 1 to 6, characterized in that: The cleaning channel and the slot array correspond to and are connected in the thickness direction of the chip body, and the depth of the cleaning channel in the thickness direction is 3 to 5 times the depth of each slot of the slot array in the thickness direction.

14. The microfluidic chip according to any one of claims 1 to 6, characterized in that: The aperture of the slot is 80-150 μm.

15. The microfluidic chip according to any one of claims 1 to 6, characterized in that: The chip body is prepared by a photolithography process and has skin-like viscoelasticity.

16. A cleaning detection system for detecting the degree of cleanliness, characterized in that: include: The microfluidic chip according to any one of claims 1 to 15; An image acquisition device, used to acquire an image of the slot array; as well as The image processing device is used to obtain the grayscale of the image.

17. The system according to claim 16, characterized in that The image acquisition device is a microscope.

18. A cleaning detection method for detecting the degree of cleanliness, characterized in that: The method is used to detect the cleaning effect of a cleaning agent on oil in skin pores based on the cleaning detection system according to claim 16 or 17, and the method comprises: A cleaning agent and a diluent are respectively injected into the chip body through the first liquid inlet and the second liquid inlet, the cleaning agent and the diluent are mixed in the mixing channel and flow into the cleaning channel, and the grease in each slot of the slot array is flushed during the flow through the cleaning channel, and then the grease is carried out from the liquid outlet; Acquire, by the image acquisition device, images of the slot array at multiple different moments during the washing process; Processing each of the images by the image processing device to obtain the grayscale of each of the images; Based on the grayscale of each of the images, the remaining amount of grease in the slot holes of the slot hole array at the multiple different time points is determined.

19. The method according to claim 18, characterized in that Also includes: Determining, according to the grayscale of each of the images, an average grayscale of at least part of the slots of the slot array at each moment; According to the average grayscale of the slot and the remaining amount of grease at the multiple different time points, a relationship between the grayscale and the remaining amount of grease is established.

20. The method according to claim 19, characterized in that The grease is an artificial simulated sebum stain; The relationship is: Grey=98.91x+30.06 Wherein, Grey is the average grayscale of the slot, and x is the remaining grease in the slot.

Images