Microfluidic chip and cleaning detection system and method for detecting cleaning degree

Abstract

The present disclosure provides a microfluidic chip and a cleaning detection system and method for detecting cleaning degree, comprising: a chip body, a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, a slot hole array for simulating skin pores, and a liquid outlet are arranged in the chip body, the first liquid inlet and the second liquid inlet are communicated with the cleaning channel through the mixing channel, the cleaning channel covers and communicates with the slot hole array, and the cleaning channel communicates with the liquid outlet.

Description

Technical Field

[0001] This disclosure relates to the field of microfluidics, and more specifically, to a microfluidic chip and a cleaning detection system and method for detecting the degree of cleanliness. Background Technology

[0002] Microfluidic chips are lab-on-a-chip devices that integrate microchannels or microcavities into a few square centimeters using micro- and nano-fabrication methods to simulate the functions and characteristics of a laboratory. By precisely manipulating the liquid within the microchannels, microfluidic chips can provide a controllable microchannel or microcavity, offering an excellent research platform for drug release, textural characterization, and other studies. Currently, various microfluidic chip designs are available on the market, capable of simulating complex biological environments such as the vascular system, tissue structures, and skin barriers, and are applied in active fields including drug testing, disease model research, molecular detection, and cell analysis. However, there are currently no microfluidic chips specifically designed for skin cleansing testing. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, embodiments of this disclosure provide at least a microfluidic chip and a cleaning detection system and method for detecting the degree of cleanliness, thereby providing a reliable, efficient, accurate, and timely experimental platform and method for assessing the cleaning effect of skin cleansers.

[0004] A first aspect of the embodiments of this disclosure provides a microfluidic chip, comprising: a chip body, wherein 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, 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 this disclosure, the chip body includes a first chip and a second chip disposed opposite to each other, the first chip having a first surface and the second chip having 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 and the second surface are in close contact so that the cleaning channel covers the slot array.

[0006] According to an embodiment of this 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 disposed on the first chip, and the liquid outlet penetrates the first chip in a direction perpendicular to the first surface.

[0007] According to embodiments of this disclosure, the microfluidic chip further includes: a clamping assembly configured to clamp the chip body from 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 in close contact.

[0008] According to an embodiment of this disclosure, the clamping assembly includes a first clamping plate and a second clamping plate respectively disposed 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 this 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 facing the first chip, the orthographic projection of the open space in a direction perpendicular to the first surface at least covering the cleaning channel and the mixing channel.

[0010] According to embodiments of this disclosure, the mixing channel extends in a bend in multiple different directions; and / or the mixing channel has multiple spaced-apart corners in its extending direction, each of the corners being a sharp angle.

[0011] According to an embodiment of this disclosure, the cross-sectional dimensions of the mixing channel are: a width of 120–170 μm parallel to the first surface; and a height of 80–120 μm perpendicular to the first surface.

[0012] According to an embodiment of this 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 in the slot array in the thickness direction.

[0013] According to embodiments of this disclosure, the diameter of the slot is 80–150 μm.

[0014] According to embodiments of this disclosure, the chip body is prepared by photolithography and the chip body has skin-like viscoelasticity.

[0015] A second aspect of the embodiments of this disclosure provides a cleaning detection system for detecting the degree of cleanliness, comprising: a microfluidic chip provided in the embodiments of this 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 embodiments of this disclosure, the image acquisition device is a microscope.

[0017] A third aspect of the embodiments of this disclosure provides a cleaning detection method for detecting the degree of cleanliness, used to detect the cleaning effect of a cleaning agent on oil in skin pores based on the cleaning detection system of the embodiments of this disclosure. The method includes: injecting a cleaning agent and a diluent into the chip body through a first inlet and a second inlet, respectively; mixing the cleaning agent and the diluent in a mixing channel and flowing into a cleaning channel, rinsing the oil in each slot of the slot array during the flow through the cleaning channel, and then carrying the oil out from the outlet; acquiring images of the slot array at multiple different times during the rinsing process using an image acquisition device; processing each image using an image processing device to obtain the grayscale of each image; and determining the amount of remaining oil in the slots of the slot array at the multiple different times based on the grayscale of each image.

[0018] According to embodiments of this disclosure, the method further includes: determining the average gray level of at least a portion of the slots in the slot array at each time step based on the gray level of each of the images; and establishing a relationship between the gray level and the amount of grease remaining based on the average gray level of the slots and the amount of grease remaining at the plurality of different times.

[0019] According to an embodiment of this disclosure, the grease is an artificially simulated sebum stain; the relationship is: Grey = 98.91x + 30.06, where Grey is the average gray level of the slot, and x is the amount of grease remaining in the slot.

[0020] The microfluidic chip provided in the embodiments of this disclosure includes at least a chip body. The chip body has a first liquid inlet, a second liquid inlet, and a mixing channel for diluting and mixing cleaning fluid. The slot array simulates the structure of skin pores. The cleaning channel covers the slot array and communicates with the slot array, thereby facilitating the simulation of the cleaning process of cleaning fluid on skin pore dirt, so as to further realize the evaluation of cleaning effect. Attached Figure Description

[0021] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings. Obviously, the drawings described below are some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings:

[0022] Figure 1 The diagram illustrates a 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 illustrated schematically.

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

[0025] Figure 2C Schematic illustration Figure 2B A magnified view of part D of the microfluidic chip.

[0026] Figure 3 Simulation diagrams of the flow field in three different channel structures are shown schematically.

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

[0028] Figure 5 A schematic diagram of a simulation of the flow field in another hybrid channel is shown.

[0029] Figure 6 The diagram illustrates how the volume fraction of cleaning agent relative to diluent varies with channel position in five different channel structures.

[0030] Figure 7 The diagram schematically illustrates a comparison of the chip length occupied by five different channel shapes when extended to the same length.

[0031] Figure 8 The illustration shows a schematic diagram of a method for fabricating a microfluidic chip using photolithography according to an example of the present disclosure.

[0032] Figure 9 The illustration shows a schematic diagram of the variation of the grayscale of a slot over time according to an example of the present disclosure.

[0033] Figure 10 A graph illustrating the variation of the average gray level of the slots over time according to an example of this disclosure is shown schematically.

[0034] Figure 11 A standard curve illustrating the variation of slot grayscale with the amount of grease remaining in the slot, according to an example of this disclosure, is shown schematically. Detailed Implementation

[0035] To make the above-disclosed objects, features, and advantages more apparent and understandable, specific embodiments of the present disclosure are described in detail below with reference to 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, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

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

[0038] When using expressions such as "at least one of A, B, and C," it should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., "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, and C, etc.). The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0039] In one exemplary embodiment of this disclosure, a microfluidic chip is provided. The microfluidic chip includes at least a chip body for simulating the cleaning process of a cleansing liquid on dirt within skin pores. For example, the chip body may have at least a partially microporous structure to mimic the pore characteristics of the skin surface. Each "pore" may be filled with a substance simulating skin secretions (such as sebum). The chip body may also have microchannels that connect to each "pore" to precisely control the flow rate and pressure of the cleansing liquid, simulating different types of cleansing products.

[0040] In some embodiments, the chip body includes 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, second liquid inlet, and liquid outlet, similar to the mixing channel and cleaning channel, are also microchannels within the chip body. The first and second liquid inlets are connected to the cleaning channel via the mixing channel. The cleaning channel covers and is connected to the slot array, and is also connected to the liquid outlet. The first and second liquid inlets can be used to receive a cleaning agent and a diluent, respectively. The cleaning agent and diluent can be mixed via the mixing channel to form a cleaning solution. It should be understood that the first and second liquid inlets can also be used to receive different components of the cleaning agent, which can then be mixed using the mixing channel to form a cleaning solution. The cleaning channel is connected to the mixing channel, allowing the mixed cleaning solution to enter the slot array and clean the substances to be cleaned within the slot array. It should be understood that this application does not limit the specific number of liquid inlets; two or more liquid inlets can be provided 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 fluid and the slots. The chip body also has a liquid outlet to allow the cleaning fluid to flow out. In embodiments of this disclosure, the slot array used to simulate skin pores has a size structure comparable to human skin. Optionally, the pore diameter is comparable to that of skin pores, for example, it can be 50–120 μm. For ease of testing and observation, the pore diameter of each slot in the slot array can be appropriately larger than that of skin pores, for example, it can be 80–150 μm. In one example, the slot array can be composed of a 10*10 array of slots spaced 500 μm apart and with a diameter of 100 μm.

[0042] In one example, the chip body can be a single piece. For instance, the chip body can be integrally formed using technologies such as 3D printing to create a first liquid inlet, a second liquid inlet, a mixing channel, a cleaning channel, and an outlet that are connected together, and has an array of slots that are connected to and covered by the cleaning channel.

[0043] In another example, the chip body can also be modular, for example, the chip body can contain at least two chips. A first liquid inlet, a second liquid inlet, a mixing channel, and a cleaning channel are connectedly disposed on one chip, and a slot array is disposed on the other chip. The cleaning channel corresponds to the area where the slot array is located, so that cleaning fluid can flow through the slot array to clean the stains in the slot array.

[0044] Figure 1 The diagram illustrates a microfluidic chip in a disassembled state according to an embodiment of the present disclosure. Figure 2A This schematic diagram shows a top view of the microfluidic chip in its assembled state. Figure 2B Schematic illustration Figure 2A The cross-sectional view of the microfluidic chip along the BB line. Figure 2C Schematic illustration Figure 2B A magnified view of a portion of the microfluidic chip at point D. (See image below.) Figures 1-2C As shown, a first chip 2 and a second chip 3, positioned opposite each other, constitute the 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 can be the lower surface of the first chip 2, and the second surface 311 can be the upper surface of the second chip 3, with the first surface 211 and the second surface 311 facing 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. From Figure 1 As can be seen, the cleaning channel 22 has an area larger than that of the slot array I. When the microfluidic chip is applied, the first surface 211 and the second surface 311 are closely attached to each other so that the cleaning channel 22 covers the entire slot array I. The slot array I contains a plurality of slots 31, each slot 31 being used to simulate a pore of the skin.

[0046] Furthermore, 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 embodiments of this disclosure, the mixing channel 23 is used to fully mix the cleaning liquid components from the first inlet 24 and the second 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 inlet 24, the second inlet 25, and the mixing channel 23 may also be non-penetratingly disposed on the first chip 2, but are formed in a groove shape at least on the first surface 211. Preferably, the depth of the mixing channel 23 is greater than or equal to the depth of the first inlet 24 and the second inlet 25. The second surface covers the mixing channel 23, thereby allowing the cleaning fluid to 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 provided 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 embodiments of this disclosure, the microfluidic chip further includes a clamping assembly. The clamping assembly may be configured to clamp the chip body from opposite sides and detachably connect the first chip and the second chip, such that a first surface of the first chip and a second surface of the second chip are in close contact.

[0051] For example, magnetic clamping components, snap-locking clamping components, and spiral-fastening clamping components can be used. For instance, clamping pieces made of magnetic material 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 and the second chip are aligned, they are attracted by magnetic force to fit tightly together. Alternatively, threaded holes can be provided on both sides of the chip body, and by screwing in a spiral clamp, pressure is gradually applied to bring the first and second chips into close contact. Complementary snap-locking structures can also be designed on both sides of the chip body, such as protruding snap-locking heads and corresponding snap-locking slots. When the first chip and the second chip are aligned and pressed together, the snap-locking heads automatically engage with the snap-locking slots, forming a stable connection.

[0052] Continue to refer to Figure 1 In the examples 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 are tightly fitted together. For example, the connector may include a bolt and a nut, wherein the bolt may pass sequentially through 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 Figures 1-2C In this design, the first clamping plate 1 is located on the side of the first chip 2 facing away from the second chip 3. The first clamping plate 1 has an open space 26 facing the first chip 2. The orthogonal projection of this open space 26 in the direction perpendicular to the first surface at least covers the cleaning channel 22 and the mixing channel 23, thereby reducing the pressure of the first clamping plate 1 on the first chip 2, reducing the risk of chip damage, and preventing the cleaning channel 22 from being excessively squeezed, which would affect the smooth flow of the cleaning fluid and the cleaning effect within the cleaning channel 22. This improves the hydrodynamic properties of the cleaning fluid within the cleaning channel and enhances 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 hybrid channel in the embodiments of this disclosure can be a non-DC channel structure, such as a serpentine channel, a micro-pillar array channel, a micro-turbine channel, etc.

[0055] To ensure that the cleaning agent and diluent are thoroughly mixed in the mixing channel, the mixing channel is configured to extend in a curved manner in at least three different directions.

[0056] The following provides three different embodiments of the hybrid channel.

[0057] In the first embodiment, to generate turbulence during mixing of the detergent and diluent, and to enhance collisions during liquid mixing to achieve full integration of different components, the mixing channel can be designed as follows: Figure 1 The channel structure shown is, for ease of description, [referred to as] Figure 1 The channel structure shown is called the first mixing channel.

[0058] Figure 1 The first mixing channel shown is a channel that extends in at least three different directions, with multiple right angles spaced apart in the extending directions. Thus, the cleaning fluid collides with each corner as it passes through it, resulting in more uniform mixing and improved cleaning power of the mixed liquid.

[0059] exist Figure 1 In the example, the first mixing channel includes multiple sequentially connected and interconnected extension segments 231. Each extension segment 231 includes a first segment extending toward the cleaning channel 22 (first direction), a second segment extending from the end of the first segment in a direction perpendicular to the first segment (second direction), a third segment extending from the end of the second segment in a direction opposite to and parallel to the extension direction of the first segment (third direction), a fourth segment extending from the end of the third segment in a direction opposite to and parallel to the extension direction of the second segment (fourth direction), a fifth segment extending from the end of the fourth segment in the same direction as the extension direction of the third segment, a sixth segment extending from the end of the fifth segment in the same direction as the extension direction of the second segment, and a seventh segment extending from the end of the sixth segment in the same direction as the extension direction of the first segment. This structure of the mixing channel can significantly improve mixing uniformity. To qualitatively verify the mixing effect of the first mixing channel in the microfluidic chip of the first embodiment, a simulation comparison study was conducted using COMSOL Multiphysics based on the theory of two-phase flow. Simulation comparison experiments were constructed Figure 3 The three simulation models shown are: the first is a straight channel, the second is a wavy channel, and the third is the one disclosed in this publication. Figure 1 The first mixing channel 23 is shown. In the experiment, the first inlet of the three models is the diluent (e.g., water) inlet, and the second inlet is the detergent phase inlet. The width and total length of the channels in the three simulation models are equal, and the mixing time of the liquids is also equal during the simulation.

[0060] To facilitate the display of the mixing effect, black is used as the simulated color for water and yellow as the simulated color for cleaning agent during the simulation. The mixing effect of the three channels can be determined based on the colors at the outlets of the three channels.

[0061] like Figure 3 As shown, the total channel lengths of the three channel simulation models are equal. Figure 3 The color axis in the diagram represents the volume fraction of the detergent phase in the mixed solution. The gradient from black to yellow (i.e., from bottom to top) on the axis represents a gradual increase in the volume fraction of the detergent phase, with orange representing a volume fraction of 0.5. When the volume fraction of the detergent phase is 0.5, it means that the detergent phase and the aqueous 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 colored boxes in the image are magnified views of the exit points of the three channels. You can clearly see the color at the exit of the first mixing channel (i.e.,...). Figure 3 The orange area percentage of the leftmost colored box is greater than that of the orange area of ​​the exit of the wavy channel (i.e., the middle colored box) than that of the orange area of ​​the exit of the straight channel (i.e., the rightmost colored box).

[0063] The simulation results show that the volume fraction of the cleaning agent 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 is, for ease of description, [referred to as] Figure 4 The channel structure shown is called the second hybrid channel. The second hybrid channel can also be called a multi-hedge channel. Figure 4 This 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 that extends in three different directions, with multiple right angles spaced apart along the extension direction. As a result, the cleaning fluid collides with each angle as it passes through it, allowing for more uniform mixing and improving the cleaning power of the mixed liquid.

[0066] exist Figure 4 In the example, the second mixing channel includes at least two extensions 232, the inlet end of each extension 232 being connected to a first liquid inlet and a second liquid inlet, and the outlet end of each extension being connected to a cleaning channel. Each extension includes a first straight section 2321 extending along a first direction, a second straight section 2322 extending along a second direction, and a plurality of square sections 2323. At least a portion of the square sections extends along a third direction different from the first and second directions, for example, in... 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, for example... Figure 4 The square segment 2323 is located on the second straight segment 2322, and at least one of the multiple square segments is located on another square segment, for example... Figure 4 The smaller square section 2325 is located on the larger square section 2326. This structure can significantly improve the mixing uniformity of the mixing channel.

[0067] In the third embodiment, the mixing channel can be designed as follows: Figure 5 The channel structure shown is, for ease of description, [referred to as] Figure 5 The channel structure shown is called the third mixing channel, which can also be called a vortex channel. Figure 5 This 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 that extends in more than three different directions, so that the cleaning fluid can be mixed more evenly as it passes through the curved channel, thereby improving the cleaning ability of the mixed liquid.

[0069] exist Figure 5 In the example, the third mixing channel includes multiple extension segments 233 connected sequentially. Each extension segment 233 extends around a different central spiral, with each extension segment 233 extending inward from its inlet end toward its center spiral to its center, and then spiraling outward from its center spiral to its outlet end. Figure 5Taking the first extension segment 233 as an example, this extension segment 233 spirals inward from its inlet end 2331 toward its center 2332, and then spirals outward from its center 2332 to its outlet end 2333. The mixing channel of this structure can significantly improve the mixing uniformity.

[0070] 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 conducted using COMSOL Multiphysics based on the theory of two-phase flow, comparing the second and third mixing channels with straight channels and wavy channels (not shown in the figure). 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 channels and straight channels.

[0071] To quantitatively verify the mixing effect of the first, second, and third mixing channels in the microfluidic chip of the first to third embodiments of this disclosure, the inventors also drew schematic diagrams of the detergent volume fraction at the outlet 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. The volume fraction of the detergent phase was used as a quantitative evaluation index of the degree of mixing, and the degree of closeness of the volume fraction of the detergent phase in each channel to 0.5 was used as a quantitative evaluation basis. The closer it is to 0.5, the better the mixing effect.

[0072] like Figure 6 As shown, the horizontal axis represents the longitudinal direction on the cross-section of the channel outlet, the origin of the horizontal axis represents any point at the bottom of the cross-section of the channel outlet, the direction of the horizontal axis represents the direction from the bottom to the top of the cross-section of the channel outlet, and the vertical axis represents the volume fraction of the detergent phase. Figure 6 The dashed line represents the ideal curve of complete mixing, indicating a volume fraction of 0.5 for the detergent phase.

[0073] Figure 6 The volume fraction curves of the cleaning agent phase at the outlets of the first, second, third, wavy, and straight channels show that the curves of the first, second, and third mixing channels are closest to the ideal curve, indicating that the mixing effect of the first, second, and third mixing channels is significantly better than that of the wavy and straight channels.

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

[0075] Figure 7 The experimental results are shown, by Figure 7It can be seen that, with the same total channel extension length, the first, second and third hybrid channels occupy significantly less chip length than straight channels and wavy channels, which helps to reduce chip size.

[0076] According to embodiments of this disclosure, the cross-sectional dimension of the mixing channel 23 can be smaller than that of the first liquid inlet and the second liquid inlet to increase the liquid flow rate and accelerate mixing. Optionally, the cross-sectional dimension of the mixing channel 23 is a width of 120–170 μm parallel to the first surface; and a height of 80–120 μm perpendicular to the first surface.

[0077] According to embodiments of this disclosure, the cleaning channel 22 and the slot array I correspond to and are connected in the thickness direction of the chip body. Figure 1 As shown in Figure 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 in the slot array I in the thickness direction, so as to better utilize capillary force to guide the cleaning liquid into the slots and generate sufficient shear force when the cleaning liquid flows in the slot array area, ensuring that each slot is thoroughly cleaned. Optionally, the distance between the end face of the slot array I near the cleaning channel 22 and the boundary of the cleaning channel 22 near the slot array I is 1200 μm, and the distance between the boundary of the slot array I near the outlet 21 and the center of the outlet is 8500 μm. The slot array I is located on the axis of symmetry of the cleaning channel; in some embodiments, the slot array I corresponds to the central region of the cleaning channel.

[0078] The microfluidic chip of this disclosure embodiment has a chip body that can be prepared by photolithography and has skin-like viscoelasticity.

[0079] Specifically, in the embodiments of this disclosure, a chip with a structure similar to skin pores can be fabricated by modeling and simulating the distribution of real pores, then using a high-precision fabricated mask, and finally through exposure, molding, and other operations. Polydimethylsiloxane, hydrogel, and polyurethane can be used as materials for the microfluidic chip.

[0080] Figure 8 A schematic diagram illustrates a method for fabricating a microfluidic chip using photolithography according to an example of this disclosure. For example... Figure 8As shown, in the example disclosed herein, polydimethylsiloxane (PDMS) is used as the material for the microfluidic chip. The process S1 represents spin coating, where a 100-micron photocurable adhesive is uniformly coated onto a clean silicon wafer surface using a spin coater. The process S2 represents exposure, where UV-curable light and photoresist are placed on opposite sides of a photomask, and then UV light is used to cure the photoresist. The process S3 represents development, where the uncured photoresist is absorbed by the developer, revealing the photomask pattern and creating bumps resembling pores. The process S4 represents casting, where PDMS thermosetting agent is cast onto the chip and heated at a constant temperature for a period of time. The process S5 represents molding, where the PDMS is removed after curing, resulting in depressions with a pore-like structure.

[0081] Embodiments of this disclosure also provide a cleaning detection system, including: a microfluidic chip provided in the embodiments of this 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 embodiments of this disclosure, cleaning experiments can be conducted using microfluidic chips. An image acquisition device acquires images of the slot array at any given time, and an image processing device processes the acquired images to characterize their grayscale.

[0083] According to embodiments of this disclosure, the image acquisition device can be a microscope. One example is that a camera mounted on the microscope captures an image of a sample under the microscope, converts the optical image into digital image data, and then uses an image processing device to process the digital image data to obtain the grayscale value of the image.

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

[0085] Embodiments of this disclosure also provide a cleaning detection method for detecting the cleaning effect of a cleaning agent on oil in skin pores based on a cleaning detection system according to embodiments of this disclosure. The cleaning detection method includes at least operations S601 to S604.

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

[0087] In operation S602, the image acquisition device acquires images of the slot array at multiple different moments during the rinsing process. For example, the slot array can be photographed at fixed time intervals to obtain images representing the current state of the slot array. An exemplary time interval can be tens of seconds; for example, it can be set to take pictures at 40s, 80s, 120s, and 160s after the injection of cleaning agent and diluent to acquire images of the slot array. Alternatively, images can be taken of each slot in the slot array at the same moment, or a sufficiently clear image of the entire slot array can be captured to identify the state of each slot in the image.

[0088] In operation S603, the image processing device processes each image to obtain the grayscale value of each image.

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

[0090] For example, after acquiring images of the slot array or individual slots using a microscope equipped with a camera, these images can be processed using an image processing device to obtain the grayscale value of each slot. Since different amounts of grease will produce varying degrees of light absorption or scattering under illumination, thus affecting the final image's grayscale value, the remaining amount of grease within the slots can be determined based on the grayscale values ​​of the slots presented in images taken at different times. Furthermore, the cleaning effect of the cleaning solution can be analyzed by examining changes in the remaining grease amount.

[0091] Figure 9 A schematic diagram illustrating the observation of the grayscale change of slots over time according to an example of this disclosure is provided. It shows the grayscale change over time for five selected slots. From... Figure 9 As can be seen from the images taken at 40-second intervals, the grayscale value of each slot decreases (the color becomes brighter) over time, indicating that the amount of grease remaining in the slots gradually decreases. Figure 10 A schematic diagram illustrates a graph showing the variation of the average grayscale of a slot over time according to an example of this disclosure, which demonstrates the relationship with... Figure 9 The same trend was observed: the average gray value in the five selected slots decreased over time, indicating that the grease in the slots was gradually cleaned and reduced.

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

[0093] In operation S605, the average gray level of at least a portion of the slots in the slot array is determined based on the gray level of each image.

[0094] When operating S606, the relationship between grayscale and grease residue is established based on the average grayscale of the slot and the amount of grease remaining at multiple different times.

[0095] The method disclosed herein can obtain the "remaining amount of oil - gray level" standard curve required for gray level analysis by establishing the relationship between gray level and remaining amount of oil. Subsequently, the remaining amount of oil can be directly obtained from the measured gray level using only the above standard curve.

[0096] Optionally, the grease is artificially simulated sebum. In this example, the proportion of the artificially simulated grease mixture in the micropore groove to the entire groove is defined as the grease residue. Before the cleaning experiment begins, the grayscale value of the groove is measured. Then, the grayscale value is measured when the grease residue in the groove reaches certain values ​​during the experiment. After thorough cleaning at the end of the experiment, the grayscale value is measured again. By fitting the measured grayscale values, a standard curve is obtained showing the change in groove grayscale with the grease residue in the groove. Figure 8 As shown.

[0097] exist Figure 11 In the text, the relationship between grayscale and residual grease is as follows:

[0098] Grey = 98.91x + 30.06

[0099] Where Grey is the average gray level of the slot, and x is the amount of grease remaining in the slot.

[0100] The correlation coefficient of the obtained curve is:

[0101] R 2 =0.9714,

[0102] This indicates that the fitted equation has a fairly good correlation.

[0103] By establishing a standard curve showing the change in grease density in the slot as a function of the amount of grease remaining in the slot, the cleaning effect of various cleaning agents on the grease in the slot can be detected in real time.

[0104] For example, when it is necessary to test the cleaning effect of a new cleaning agent on artificially simulated sebum stains, the cleaning detection system disclosed herein can be used to obtain the corresponding grayscale value. Then, the grayscale value can be directly substituted into the above equation to obtain the amount of grease remaining after cleaning, thereby achieving rapid detection of the cleaning effect.

[0105] Unless otherwise specified, the numerical parameters in this specification and the appended claims are approximate values ​​and can be changed according to the desired characteristics obtained from the content of this disclosure. Specifically, all figures used in the specification and claims to indicate the content of composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. Generally, this means that there may be variations of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments.

[0106] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0107] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A microfluidic chip, characterized in that, include: The chip body includes 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 connected to the cleaning channel through the mixing channel. The cleaning channel covers the slot array and is connected to the slot array. The cleaning channel is connected to the liquid outlet.

2. The microfluidic chip according to claim 1, characterized in that, The chip body includes a first chip and a second chip disposed opposite to each other, the first chip having a first surface and the second chip having 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 and the second surface are in close contact 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 disposed on the first chip, and the liquid outlet penetrates 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 opposite sides 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 in close contact.

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 disposed 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.

6. The microfluidic chip according to claim 5, characterized in that, The first clamp is located on the side of the first chip facing away from the second chip. The first clamp has an open space facing 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.

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 spaced-apart corners in its extending direction, each of the corners being a sharp angle.

9. The microfluidic chip according to claim 8, characterized in that, The hybrid channel includes a plurality of extension segments connected in sequence. Each extension segment includes a first segment extending in a first direction, a second segment extending in a second direction, a third segment extending in a third direction, and a fourth segment 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, and 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 a portion of the directional 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 disposed on the first straight section or the second straight section, and at least one of the plurality of square sections is disposed on another square section.

11. The microfluidic chip according to claim 7, characterized in that, The mixing channel includes a plurality of extension segments connected in sequence, each extension segment extending spirally around a different central point. Each extension segment extends inward from its respective inlet end toward its respective central point spiral to the center, and then extends outward from the central point spiral to its 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 in the slot array in the thickness direction.

14. The microfluidic chip according to any one of claims 1 to 6, characterized in that, The diameter 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 photolithography and has skin-like viscoelasticity.

16. A cleaning detection system for detecting the degree of cleanliness, characterized in that, include: The microfluidic chip as described in any one of claims 1 to 15; Image acquisition device, used to acquire an image of the slot array; as well as An image processing device for acquiring 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 as described in claim 16 or 17, the method comprising: The cleaning agent and the diluent are injected into the chip body through the first inlet and the second inlet, respectively. The cleaning agent and the diluent are mixed in the mixing channel and then flow into the cleaning channel. During the process of flowing through the cleaning channel, the grease in each slot of the slot array is rinsed and then the grease is carried out from the outlet. The image acquisition device acquires images of the slot array at multiple different moments during the rinsing process. The image processing device processes each of the images to obtain the grayscale of each image; Based on the grayscale of each image, the amount of grease remaining in the slots of the slot array at the multiple different times is determined.

19. The method according to claim 18, characterized in that, Also includes: Based on the grayscale of each of the images, determine the average grayscale of at least a portion of the slots in the slot array at each time step; Based on the average gray level of the slot and the amount of grease remaining at the multiple different times, a relationship between the gray level and the amount of grease remaining is established.

20. The method according to claim 19, characterized in that, The oil is artificially simulated sebum stains; The relationship is as follows: Grey = 98.91x + 30.06 Where Grey is the average gray level of the slot, and x is the amount of grease remaining in the slot.

Images