A spiral microfluidic chip for tumor marker detection

Abstract

The application discloses a spiral micro-fluidic chip for tumor marker detection, which comprises a spiral channel, the total number of turns of the spiral channel is two, the radius increase between the two turns of the channel is 5mm, the spiral channel as a whole gradually expands and distributes outward following the law of Archimedes spiral line, the inner side end of the spiral channel is provided with a bifurcated inlet, the other end of the spiral channel is provided with a bifurcated outlet, and the direction of the spiral channel from the bifurcated inlet to the bifurcated outlet is sequentially provided with a convex structure I and a convex structure II. The spiral channel and the convex structure are arranged, so that accurate particle focusing and separation can be realized, the synergistic effect of the secondary flow and the Dean flow is utilized, the preliminary focusing and the fine focusing of the particles are realized at different stages, the particles with different particle sizes can be accurately separated into different outlet areas, and the accurate separation capacity helps to improve the accuracy and the sensitivity of detection.

Description

Technical Field

[0001] This invention relates to the field of microfluidic chip technology, and more specifically, to a spiral microfluidic chip for tumor marker detection. Background Technology

[0002] Molecular detection and analysis of biomarkers are key technologies for the diagnosis and treatment of major diseases such as cancer. Point-of-care testing (POCT) is an advanced technology that combines biosensing with sensor signal analysis systems to achieve real-time and accurate biomarker analysis. POCT has many advantages such as simplicity, low cost, and convenience, and is an ideal and effective alternative to large-scale equipment for biomarker detection. It has great potential in improving the diagnosis and treatment of pathological diseases. It is generally composed of a microfluidic chip, a biosensor, a flexible pressure sensor chip, and a miniaturized detection system to integrate a portable tumor marker detection and analysis system. This system includes a biosensor microfluidic chip for biomarker capture, a flexible pressure sensor array that generates an electrical signal upon triggering, and a portable system for signal acquisition, analysis, and display of results.

[0003] Existing microfluidic chips still have the following problems in detection applications. When detecting tumor marker molecules, because the detection of tumor markers requires the specific identification of target molecules, the current purification and separation methods of sample particles using microfluidic chips cannot effectively perform multi-level separation, enrichment and purification of molecules of different particle sizes. This results in the presence of non-target molecules in the sample that are similar in structure or particle size to the tumor markers. Molecules of different particle sizes can interfere with each other, and these molecules can also non-specifically bind to the detection reagents, leading to false positive results and ultimately affecting the accuracy of clinical test results. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a helical microfluidic chip for tumor marker detection. By utilizing the synergistic effect of secondary flow and Dean flow, it achieves preliminary and fine focusing of particles at different stages, enabling precise separation of particles of different sizes into different exit regions. This precise separation capability helps improve the accuracy and sensitivity of detection, and can more effectively analyze and detect tiny particles such as tumor markers, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a spiral microfluidic chip for tumor marker detection, comprising a spiral channel, wherein the spiral channel has a total of two turns, and the radius between the two turns increases by 5 mm. The spiral channel extends outward gradually following the Archimedean spiral pattern. A bifurcated inlet is provided at the inner end of the spiral channel, and a bifurcated outlet is provided at the other end of the spiral channel. From the bifurcated inlet to the bifurcated outlet, the spiral channel is provided with a protrusion structure I and a protrusion structure II in sequence. The protrusion structure I is located on the outer wall surface of the spiral channel within the range of 0.25 to 0.375 turns and protrudes outward by 50 μm. The protrusion structure II is located on the inner wall surface of the spiral channel within the range of 1.25 to 1.5 turns and protrudes outward by 50 μm.

[0006] In a preferred embodiment, the bifurcated inlet branches into two inlets, with the left one being a sheath flow inlet with a width of 150 μm and the right one being a sample inlet with a width of 120 μm, and the sheath flow inlet and the sample inlet are set at a 70° angle.

[0007] In a preferred embodiment, the forked outlet branches into three outlets: a 20μm particle outlet on the left, a 5μm particle outlet in the middle, and a 100nm particle outlet on the right. The outlet widths from left to right are 78μm, 90μm, and 104μm, respectively, and the included angle between adjacent outlets is 30°.

[0008] In a preferred embodiment, a tangent line is drawn along the outer edge of the upper right trajectory of the spiral channel, with the protruding structure II at a 90° angle to the tangent line and the protruding structure I at a 45° angle to the tangent line.

[0009] In a preferred embodiment, the left and right edges of the protrusion structure I and protrusion structure II are both perpendicular to the surface of the spiral channel.

[0010] In a preferred embodiment, the overall channel width of the spiral channel is 300 μm and the channel height is 100 μm, and the sample movement directions of the bifurcated inlet and the bifurcated outlet are distributed in the same direction.

[0011] The technical effects and advantages of this invention are as follows: This invention achieves passive separation by setting up a spiral channel and additional protrusion structure: This invention does not require external application of electric fields, magnetic fields or other active driving forces. It only relies on the special structural design of the microfluidic chip and the fluid dynamics effects such as secondary flow and Dean flow generated when the fluid flows in the channel to achieve the separation of three different particle sizes. This passive separation method has the advantages of simple structure, low cost and easy integration. It avoids the problems of electromagnetic interference and complex power supply configuration that may be caused by active driving methods, and improves the practicality and reliability of microfluidic chips. Improving particle collection efficiency: By setting protruding structures at specific locations, the flow state near the wall is changed, especially for the acceleration of 20μm particles. This acceleration allows 20μm particles to reach the outlet more quickly, thereby shortening the particle collection time and improving the particle collection efficiency. In practical applications such as tumor marker detection, faster particle collection can speed up the detection process and increase the detection throughput, which is of great significance for clinical diagnosis and research. Precise particle focusing and separation: By utilizing the synergistic effect of secondary flow and Dean flow, preliminary and fine focusing of particles are achieved at different stages, which can accurately separate particles of different sizes to different exit regions. This precise separation capability helps to improve the accuracy and sensitivity of detection, and can more effectively analyze and detect tiny particles such as tumor markers, providing a more reliable basis for the early diagnosis and treatment of tumors. Excellent fluid dynamics characteristics: By fully utilizing professional principles such as boundary layer theory, planar eddy current, secondary flow and Dean flow in fluid mechanics, and by rationally designing the structure of the microfluidic chip, the flow state of the fluid in the channel is optimized, so that the motion of particles in the fluid can be precisely controlled. This ingenious use of fluid dynamics characteristics provides a new method and idea for particle separation, which has significant innovation and technological foresight. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partially enlarged structural schematic diagram of the present invention; Figure 3This is a particle distribution analysis cloud map at the bifurcated exit after the protrusions I and II of the present invention are distributed at different positions on the spiral channel. `speed` represents velocity (m / s). Wherein (A1) is a spiral channel with a 50μm protrusion on the outer wall at 0.25~0.5 turns and a 100μm protrusion on the outer wall at 0.25~0.5 turns and a 100μm protrusion on the inner wall at 1.25~1.5 turns; and (A3) is a spiral channel with a 50μm protrusion on the outer wall at 0.25~0.5 turns and a 100μm protrusion on the inner wall at 1.25~1.5 turns. (A4) is a spiral channel with a 50 μm protrusion on the inner wall at 0.25~0.375 turns, and a spiral channel with a 50 μm protrusion on the outer wall at 1.25~1.375 turns, (A5) is a spiral channel with a 100 μm protrusion on the outer wall at 0.25~0.375 turns and a spiral channel with a 50 μm protrusion on the outer wall at 0.25~0.375 turns and a spiral channel with a 50 μm protrusion on the inner wall at 1.25~1.5 turns, and (A7) is an existing Archimedes spiral channel; Figure 4 This is a schematic diagram showing the recovery rates of 100nm, 5μm, and 20μm particles at the outlet position of the present invention, where the vertical axis represents the particle recovery rate and the horizontal axis represents the particle recovery rate. Figure 3 The seven experimental groups are (A1), (A2), (A3), (A4), (A5), (A6), and (A7). Figure 5 for Figure 3 A schematic diagram showing the shortest time required for 20μm particles to reach the exit position in the channels of the seven experimental groups (A1), (A2), (A3), (A4), (A5), (A6) and (A7), where the vertical axis represents the required time (s). Figure 6 This is a velocity analysis cloud map of the exit section of the bifurcated exit of the present invention, showing the velocity analysis of the 20μm particle on the left, the 5μm particle in the middle, and the 100nm particle on the right at the exit. Figure 7 This is a sample velocity analysis cloud diagram of a local cross-section and a local longitudinal section of the spiral channel of the present invention; Figure 8 This is a schematic diagram of the particle distribution at the bifurcation exit when the spiral channel has 2 turns, where speed represents velocity (m / s). Figure 9 This is a schematic diagram of the spiral channel width optimization analysis of the present invention. Speed ​​represents speed (m / s), which includes 6 experimental groups: (1) channel width 120μm, (2) channel width 180μm, (3) channel width 240μm, (4) channel width 300μm, (5) channel width 360μm, and (6) channel width 420μm. Figure 10This is a schematic diagram of the spiral channel height optimization analysis of the present invention, which includes 11 experimental groups: (1) channel height 50μm, (2) channel height 55μm, (3) channel height 60μm, (4) channel height 65μm, (5) channel height 70μm, (6) channel height 75μm, (7) channel height 80μm, (8) channel height 85μm, (9) channel height 90μm, (10) channel height 95μm, (11) channel height 100μm; Figure 11 This is a schematic diagram of particle distribution at the exit of the spiral channel of the present invention under different radius increases. Speed ​​represents velocity (m / s). It includes 6 experimental groups: (1) spiral channel with a radius increase of 1 mm, (2) spiral channel with a radius increase of 2 mm, (3) spiral channel with a radius increase of 3 mm, (4) spiral channel with a radius increase of 4 mm, (5) spiral channel with a radius increase of 5 mm, and (6) spiral channel with a radius increase of 6 mm.

[0013] The attached diagram is labeled as follows: 1. Spiral channel; 2. Forked inlet; 3. Forked outlet; 4. Protrusion structure I; 5. Protrusion structure II. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] As attached Figure 1 To be continued Figure 11 The spiral microfluidic chip for tumor marker detection shown includes a spiral channel 1 with two turns and a radius increase of 5 mm between the two turns. The spiral channel 1 expands outward gradually following the Archimedean spiral pattern. A bifurcated inlet 2 is provided at the inner end of the spiral channel 1, and a bifurcated outlet 3 is provided at the other end of the spiral channel 1. From the bifurcated inlet 2 to the bifurcated outlet 3, the spiral channel 1 is provided with a protrusion structure I 4 and a protrusion structure II 5. The protrusion structure I 4 is located on the outer wall surface of the spiral channel 1 in the range of 0.25 to 0.375 turns and protrudes outward by 50 μm. The protrusion structure II 5 is located on the inner wall surface of the spiral channel 1 in the range of 1.25 to 1.5 turns and protrudes outward by 50 μm.

[0016] The bifurcated inlet 2 branches into two inlets: a 150μm wide sheath flow inlet on the left and a 120μm wide sample inlet on the right, with a 70° angle between them. The bifurcated outlet 3 branches into three outlets: a 20μm particle outlet on the left, a 5μm particle outlet in the middle, and a 100nm particle outlet on the right. The outlet widths from left to right are 78μm, 90μm, and 104μm, respectively, with a 30° angle between adjacent outlets. A tangent line is drawn along the outer edge of the upper right trajectory of the spiral channel 1. The protrusion structure II5 is distributed at a 90° angle to this tangent line, and the protrusion structure I4 is distributed at a 45° angle to this tangent line. Utilizing the design of the bifurcated inlet 2 and bifurcated outlet 3, operators can easily input sheath flow fluid and fluid samples into the spiral channel 1 through the bifurcated inlet 2. Operators can also conveniently collect sample molecules of three different particle sizes at the three outlet positions, further improving the practicality of the device.

[0017] The left and right edges of the protrusions I4 and II5 are perpendicular to the surface of the spiral channel 1. The overall channel width of the spiral channel 1 is 300 μm and the channel height is 100 μm. The sample movement directions of the bifurcated inlet 2 and the bifurcated outlet 3 are in the same direction.

[0018] Please refer to the attached instruction manual for details. Figure 3 In the seven groups of experiments, except for the A7 basic Archimedes spiral channel used as a control, the other channels A1 to A6 could all increase the flow rate of 20μm particles and collect 20μm particles at the outlet. The A7 control group had the best separation effect on 100nm and 5μm particles, but it could not collect 20μm particles. The A6 channel had a similar separation and focusing effect on 100nm and 5μm particles as the A7 control group and could collect 20μm particles. The separation and focusing effect of the other channels A1 to A5 on 100nm and 5μm particles was not as good as that of the A6 channel. Included in the instruction manual Figure 4 and attached Figure 5 It is evident that only the A6 channel achieved a 100% recovery rate for all three types of particles. The 20μm particles in the A6 group can reach the exit within 0.7s, which is the optimal solution within a reasonable and acceptable range. Therefore, the final choice was a spiral channel 1 with a 50μm protrusion on the outer wall at 0.25~0.375 turns and on the inner wall at 1.25~1.5 turns.

[0019] Please refer to the attached instruction manual for details. Figure 8When the number of rotations is 2, the spiral channel 1 has a focusing and sorting effect on particles. The focusing width of 100nm particles and 5μm particles is the smallest, and the focusing areas of the two types of particles are staggered. Therefore, it can be determined that 2 rotations is the optimal solution for the spiral channel 1.

[0020] Please refer to the attached instruction manual for details. Figure 9 The basic Archimedes curve used in this simulation experiment is represented by a spline curve parametric equation in the software Solidworks. Xt=(Rc+R*t)*cos(2*π*t) Yt=(Rc+R*t)*sin(2*π*t) The control is performed by Rc, where R is the initial radius of the curve, R is the increase in radius for each additional revolution of the curve, and t is a parameter that controls the number of revolutions of the curve. To standardize the labeling of particles across different channel widths, a distribution range formula is proposed: (Px−x) / Cw Where Px is the distance of the particle relative to the inner wall of the channel, x is the distance from the inner wall of the channel to the origin, and Cw is the width of the channel.

[0021] First, tests were conducted on Archimedes curves with Rc1=5, R=1, t1=0, and t2=2. The width of the helical channel was controlled by changing the value of Rc2. Rc2 values ​​of 5.12, 5.18, 5.24, 5.3, 5.36, and 5.42 corresponded to helical channel widths of 120μm, 180μm, 240μm, 300μm, 360μm, and 420μm, respectively. (The last sentence appears to be incomplete and possibly refers to a separate, unrelated statement.) Figure 9 The velocity contour plots show that, at the same inlet flow rate, the smaller the cross-sectional area of ​​the channel, the faster the velocity within the channel. In channels with widths of 120μm, 180μm, and 240μm, the high flow rates result in a disordered particle distribution, with neither 5μm nor 100nm particles effectively focused. In the 300μm channel, 20μm, 5μm, and 100nm particles exhibit a regular arrangement with decreasing particle size from right to left, and only a small overlap between 5μm and 20μm particles. This channel also provides the best focusing effect for 100nm particles. Channels with widths of 360μm and 420μm offer good focusing for 5μm and 20μm particles, but poor focusing for 100nm particles. Therefore, the 300μm channel is the optimal solution.

[0022] Please refer to the attached instruction manual for details. Figure 10It can be observed that as the channel height increases, 100nm particles exhibit a lack of focus at channel heights of 50μm~55μm, and a shift from left-side focusing to right-side focusing at channel heights of 60μm~100μm. 5μm particles gradually shift from center-right focusing to left-side focusing, and finally back to center-right fine focusing. 20μm particles shift from right-side fine focusing to left-side fine focusing at channel heights of 50μm~85μm, exhibiting extremely fine focusing at a channel height of 90μm, and extremely close focusing at channel heights of 95μm~100μm. Near the inner wall, particles cannot move to the exit within 1 second. Although the 100μm high spiral channel prevents 20μm particles from moving smoothly to the exit, during the separation process, the 20μm particles begin to adhere closely to the inner wall from around 1.25 turns and maintain this trend until the end of the simulation time. Moreover, among the heights involved in this experiment, the 100μm high channel has a better overall focusing effect on 100nm and 5μm particles, enabling most of the two types of particles to be separated. Considering the overall focusing effect, the 100μm high spiral channel 1 is selected as the optimal solution.

[0023] Please refer to the attached instruction manual for details. Figure 11 In all spiral channels with optimized radius increases, focused separation of 100nm and 5μm particles can be achieved. Figure 11 The distribution range clearly shows that effective focusing of 100nm particles can be achieved when the radius value is 2~6mm. The focusing effect of 5μm particles is the best when the radius value is 5mm. At the same time, it is staggered from the focusing area of ​​100nm particles. Therefore, the radius increase of 5mm is determined to be the optimal solution.

[0024] Working principle of the invention: Step 1: At the bifurcation inlet 2 of the microfluidic chip, a sheath flow fluid with a velocity of 0.7 m / s is introduced through the sheath flow inlet. From a fluid dynamics perspective, the sheath flow forms a stable laminar flow pattern in the microchannel, which constrains and guides the subsequently entering sample fluid, preventing diffusion and turbulence within the channel. Simultaneously, a fluid particle sample with a velocity of 0.25 m / s is input through the sample inlet. These particles, enveloped by the sheath flow, enter the subsequent helical channel. At this point, the Reynolds number of the fluid is relatively low, and it is in a laminar flow state, with the particles primarily affected by viscous forces.

[0025] Step 2: First Particle Acceleration: A 50μm protrusion I4 is placed on the outer wall of the spiral channel 1 at 0.25-0.375 turns. When the fluid flows through this protrusion I4, the flow field around it changes. According to boundary layer theory, the fluid velocity near the wall changes. Under the influence of the protrusion I4, the original laminar boundary layer is disturbed, generating planar vortices. The existence of these planar vortices causes the particles in the fluid to be subjected to additional forces, thus achieving the first acceleration of all particles. From the perspective of momentum transfer, the protrusion I4 changes the momentum distribution of the fluid, thereby giving the particles additional kinetic energy. Preliminary focusing effect: In the inner and outer wall channels of spiral channel 1 at 0.375-1.25 turns, due to the special geometry of spiral channel 1, the fluid will generate secondary flow and Dean flow during the flow process. The secondary flow is the lateral flow caused by the imbalance of centrifugal force and viscous force when the fluid flows in the curved channel. The Dean flow is the double vortex flow formed by the fluid in the cross section due to the centrifugal force in the curved channel. The synergistic effect of these two flows causes the particles to migrate in the cross section of the channel, thus achieving a preliminary but incomplete focusing effect. At this time, particles of different sizes begin to show a certain distribution trend in the cross section of the channel, but have not yet been completely separated. Targeted acceleration of 20μm particles: The protrusion structure II5 set on the inner wall of the spiral channel 1 at 1.25-1.5 turns is mainly for accelerating 20μm particles. When 20μm particles flow through the protrusion structure II5, based on the boundary layer theory and the generation mechanism of planar vortices, the particles are subjected to the velocity change caused by the protrusion structure II5 and the effect of the planar vortices, and thus gain additional acceleration. Since 20μm particles are more sensitive to this velocity change under specific flow field conditions, they can be effectively accelerated. In this process, particles of different sizes show different acceleration effects due to their different inertia and interactions with the fluid. Fine focusing and particle separation: In the ordinary channel at 1.5-2 turns of the spiral channel 1, the synergistic effect of the secondary flow and the Dean flow is utilized again. As the fluid continues to flow in the spiral channel 1, the effects of the secondary flow and the Dean flow are further enhanced, allowing particles of different sizes to be focused more precisely on the channel cross-section. Finally, three different particle sizes can be collected in the three focusing outlet regions of the bifurcated outlet 3. This is because the migration trajectories and focusing positions of particles of different sizes differ under the action of the secondary flow and the Dean flow, thus ultimately achieving particle separation.

[0026] The third step involves real-time detection of sample molecules of different particle sizes that have undergone multi-stage separation, enrichment, and purification in biological samples.

[0027] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other. In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A spiral microfluidic chip for tumor marker detection, characterized in that: The system includes a spiral channel with two turns, the radius of which increases by 5 mm. The spiral channel expands outward gradually following the Archimedean spiral pattern. A bifurcated inlet is located at the inner end of the spiral channel, and a bifurcated outlet is located at the other end. From the bifurcated inlet to the bifurcated outlet, the spiral channel is sequentially provided with a protruding structure I and a protruding structure II. Protruding structure I is located on the outer wall surface of the spiral channel within the range of 0.25 to 0.375 turns and protrudes outward by 50 μm. Protruding structure II is located on the inner wall surface of the spiral channel within the range of 1.25 to 1.5 turns and protrudes outward by 50 μm.

2. The spiral microfluidic chip for tumor marker detection according to claim 1, characterized in that: The bifurcated inlet branches into two inlets: a sheath flow inlet with a width of 150 μm on the left and a sample inlet with a width of 120 μm on the right, with the sheath flow inlet and the sample inlet set at a 70° angle.

3. The spiral microfluidic chip for tumor marker detection according to claim 1, characterized in that: The forked outlet branches into three outlets: a 20μm particle outlet on the left, a 5μm particle outlet in the middle, and a 100nm particle outlet on the right. The outlet widths from left to right are 78μm, 90μm, and 104μm, respectively, and the included angle between adjacent outlets is 30°.

4. The spiral microfluidic chip for tumor marker detection according to claim 1, characterized in that: A tangent line is drawn along the outer edge of the upper right trajectory of the spiral channel. The protruding structure II is distributed at a 90° angle to the tangent line, and the protruding structure I is distributed at a 45° angle to the tangent line.

5. The spiral microfluidic chip for tumor marker detection according to claim 1, characterized in that: The left and right edges of the protrusions I and II are perpendicular to the surface of the spiral channel.

6. The spiral microfluidic chip for tumor marker detection according to claim 1, characterized in that: The spiral channel has an overall channel width of 300 μm and a channel height of 100 μm. The sample movement directions of the bifurcated inlet and the bifurcated outlet are distributed in the same direction.

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