CN113996355B

CN113996355B - Sampling device

Info

Publication number: CN113996355B
Application number: CN202111262251.3A
Authority: CN
Inventors: 冯子寅
Original assignee: Shanghai Junzhen Life Science Co ltd
Current assignee: Shanghai Junzhen Life Science Co ltd
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2023-06-06
Anticipated expiration: 2041-10-28
Also published as: CN113996355A

Abstract

The invention relates to a sampling device comprising a microfluidic flow channel having a sample inlet (1) for receiving a biological fluid sample, an embedding (2) downstream of the sample inlet containing a reagent for processing the biological fluid sample, a mixing section (3) for mixing the biological fluid sample with the reagent, a detection zone (5) downstream of the mixing section, a waste liquid section (6) downstream of the detection zone and a vent (7), the microfluidic flow channel being configured such that a fluid can flow in the microfluidic flow channel from the sample inlet to the detection zone by a self-driving force consisting of the gravitational potential, the surface tension and the capillary force of the fluid, wherein the height of the bottom surface of the microfluidic channel is configured such that the fluid has a higher flow rate in the mixing section and reaches the detection zone at a lower flow rate. The sampling device can be manufactured cost-effectively, has a small number of parts and works reliably.

Description

Sampling device

Technical Field

The present application relates to the field of medical technology, and more particularly to a sampling device for biological fluid samples, in particular disposable consumables.

Background

Detection of biological fluid samples may be involved in life sciences research, biopharmaceuticals, medical diagnostics, and the like. The biological fluid sample may be, for example, blood, urine, body fluids, extracts of plants of humans or animals, which may be untreated or pretreated. For example, the number of red blood cells, the number of white blood cells, the cell activity, etc. can be detected for a whole blood sample. Detection of biological fluid samples may involve applications in, for example, molecular diagnostics, immunofluorescence assays, and fluorescent antibody technology.

Disclosure of Invention

The object of the present application is to provide a sampling device for biological fluid samples, which can be manufactured cost-effectively, has a small number of parts, is compact in size and can be used reliably.

To this end, a sampling device is provided, comprising a microfluidic flow channel having a sample inlet for inputting a biological fluid sample, an embedding downstream of the sample inlet containing a reagent for processing the biological fluid sample, a mixing section for mixing the biological fluid sample with the reagent, a detection section downstream of the mixing section, a waste section downstream of the detection section and a vent, the microfluidic flow channel being configured such that a fluid can flow in the microfluidic flow channel from the sample inlet to the detection section by a self-driving force consisting of the gravitational potential, the surface tension and the capillary force of the fluid, wherein the height of the bottom surface of the microfluidic channel is configured such that the fluid is accelerated by the gravitational potential of the fluid over at least part of the section of the microfluidic channel between the sample inlet and the output of the mixing section and such that the fluid is decelerated by the gravitational potential of the fluid again before reaching the input of the detection section of the microfluidic channel.

In the sampling device according to the present invention, the self-driving force is generated by using gravitational potential in addition to the surface tension and capillary force, whereby different height drops can be set in the microfluidic flow channel according to need, so that the flow rate of the biological fluid sample can be appropriately adjusted. For example, dissolution and mixing of the embedded reagent in the fluid sample may be facilitated by the reduced height of the embedding portion and/or mixing section. The fluid sample mixed with the reagent can then be suitably brought into the detection zone at a reduced flow rate by means of the re-rising height downstream of the mixing section, whereby the detection is carried out.

In the sampling device according to the invention, the change in gravitational potential results in a change in the flow rate of the fluid, wherein the fluid is mixed in the mixing section at a higher flow rate and then spread out in the detection area at a lower flow rate.

In some embodiments, the microfluidic channel may have a buffer section disposed between the mixing section and the detection zone for buffering fluid prior to entering the detection zone. The buffer section may reduce the flow rate of the fluid to be entered into the detection zone and may simultaneously reduce the eddy current remaining in the fluid, thereby may promote uniform spreading of the fluid in the detection zone.

In some embodiments, the embedding may be at least partially or fully integrated into the mixing section. Thus, proper dissolution, diffusion and mixing of the reagents can be achieved. Alternatively, in some embodiments, the embedding portion may be configured separately from the mixing section.

In some embodiments, all of the reagents may be centrally embedded in one reagent-concentrating embedding section upstream of the mixing section. In other words, the embedding part is formed completely separately from the mixing section.

In some embodiments, all of the reagents may be dispersed embedded in the mixing section, for example, may be dispersed embedded in the first half of the mixing section. In other words, the embedding is completely integrated in the mixing section.

In some embodiments, a portion of the reagents may be centrally embedded in one reagent-centralized embedding portion upstream of the mixing section, and the remaining reagents may be dispersedly embedded in the mixing section. The portion of the reagent may be, for example, a small portion of the reagent, e.g., 30% of the total reagent, and the remaining reagent may be a large portion of the reagent, e.g., 70% of the total reagent.

In some embodiments, the bottom surface of the embedding portion and/or mixing section may be lowered in height relative to the bottom surface of the sample inlet. Thus, a height drop can be generated between the sample inlet and the embedding portion, thereby increasing the flow rate of the biological fluid sample when reaching the embedding portion, and promoting the dissolution and diffusion of the reagent in the biological fluid sample.

In some embodiments, the bottom surface of the embedding and/or mixing section may remain unchanged in height along the flow direction of the fluid.

In some embodiments, the bottom surface of the embedding and/or mixing section may at least partially continuously descend along the flow direction of the fluid.

In some embodiments, the bottom surface of the reagent-concentrating embedding portion may be lowered in height relative to the bottom surface of the sample inlet, and the bottom surface of the mixing section may remain unchanged or be lowered in height relative to the bottom of the reagent-concentrating embedding portion.

In this case, the biological fluid sample can flow in the mixing section at a relatively high flow rate, which can promote the dissolution of the reagent in the biological fluid sample and the efficient and thorough mixing of the biological fluid sample with the reagent.

In some embodiments, the depth of the embedding portion and/or mixing section may remain the same or increase relative to the depth of the section of the microfluidic channel between the sample inlet and the embedding portion.

In some embodiments, the top surface of the section of the microfluidic channel from the sample inlet to the output of the mixing section may remain unchanged in height.

In some embodiments, the bottom surface of the input end of the detection zone may rise in height relative to the bottom surface of the output end of the mixing section. Thus, the flow rate of the biological fluid sample when reaching the detection zone can be reduced, and the biological fluid sample can be promoted to be uniformly spread in the detection zone.

In some embodiments, the bottom surface of the buffer section may rise in height relative to the bottom surface of the mixing section.

In some embodiments, the floor of the buffer section may rise in a jump at the input of the buffer section relative to the floor of the output of the mixing section.

In some embodiments, the bottom surface of the buffer section may rise continuously, at least partially, along the direction of fluid flow.

In some embodiments, the bottom surface of the input end of the detection zone may rise in height relative to the bottom surface of the output end of the buffer section or be at the same height as the bottom surface of the output end of the buffer section. Thereby, a uniform spreading of the biological fluid sample in the detection zone may be facilitated.

In some embodiments, the buffer section may have a bend. The bends may increase the flow resistance to achieve a further reduction in fluid flow rate in addition to the height head to facilitate uniform spreading of the biological fluid sample in the detection zone.

In some embodiments, the bend may have a bend angle of 60 ° to 120 °, such as a bend angle of 75 ° to 105 °, preferably a bend angle of about 90 °.

In some embodiments, the buffer section may restore the fluid to a laminar flow state.

In some embodiments, the microfluidic channel may have no buffer section, wherein the mixing section may be directly connected with the detection zone.

In some embodiments, the bottom surface of the mixing section may descend in the upstream first section and rise again in the downstream second section, in particular immediately following the first section. Thus, the fluid may be mixed at an increased flow rate in a first section upstream of the mixing section and at a reduced flow rate in a second section downstream of the mixing section, and thus reach the detection zone at a reduced flow rate.

In some embodiments, a first micro valve for controlling the flow rate of the fluid may be provided between the sample inlet and the embedding part. A suitable flow rate may facilitate dissolution of the reagent contained in the embedding portion into the biological fluid sample input from the sample inlet.

In some embodiments, a second microvalve for controlling the flow rate of the fluid may be provided between the mixing zone and the detection zone. A suitable fluid may facilitate uniform spreading of the biological fluid sample in the detection zone.

In some embodiments, a second micro valve for controlling the flow rate of the fluid may be provided in the buffer section. A suitable fluid may facilitate uniform spreading of the biological fluid sample in the detection zone.

In some embodiments, the mixing section may have at least one structure selected from the group consisting of: bending part, reducing part, microcolumn. By means of the structure, the generation of vortices of the biological fluid sample in the mixing section and thus the mixing of the reagents in the biological fluid sample can be promoted.

In some embodiments, the mixing section may comprise a plurality of side-by-side subsections, each subsection may have at least one structure selected from the group.

In some embodiments, each sub-segment may have a plurality of bends and a plurality of reducing portions.

In some embodiments, each bend may have a bend angle of 20 ° to 160 °, for example 30 ° to 150 °, preferably 45 ° to 120 °.

In some embodiments, the microfluidic channel may have a continuously descending floor in the section from the sample inlet to the output of the buffer section and/or a jump ascending floor in the detection zone 5.

In some embodiments, the microfluidic channel may have a constant depth in a section from the sample inlet to the output of the buffer section, wherein preferably the microfluidic channel has a first width before the buffer section and a second width in the buffer section that is increased compared to the first width.

In some embodiments, the microfluidic channel may have a flow length of 80-200 mm, e.g., 100-160 mm, in a section from the sample inlet to the output of the buffer section, and/or a drop of 1-4 mm, e.g., 2-3 mm, between the sample inlet and the deepest point in a section from the sample inlet to the output of the buffer section.

In some embodiments, the detection zone may be configured as a planar region.

In some embodiments, the detection zone may have an increased width dimension and/or a reduced depth in the center compared to the two ends, with reference to the flow direction of the fluid. Thereby, the formation of dead zones in the detection zone, where the biological fluid sample cannot reach, in which gas bubbles can form, can be prevented.

In some embodiments, the detection zone may have a boss protruding from the bottom surface and/or a boss protruding from the top surface in the central region. In particular, by combining the variations in width and the variations in height of the detection zone, a uniform spreading of the biological fluid sample mixed with the reagent in the detection zone may be achieved, which may be advantageous for detection of the biological fluid sample in the detection zone. In this case, a uniform spreading of the fluid in the detection zone can be promoted by a change in the ratio of width to depth in the detection zone.

In some embodiments, the side wall of the detection zone in the inlet region may transition to the central region in a curve with reference to the direction of flow of the fluid, the shape of the curve being selected such that the fluid is able to flow in the detection zone with a substantially uniform spread. Thereby, it is possible to further achieve uniform spreading of the fluid in the detection zone and further prevent the formation of dead zones in the detection zone.

In some embodiments, in the entrance region of the detection zone, the width of the detection zone may first be incrementally increased and then incrementally increased.

In some embodiments, upstream of the detection zone, the microfluidic flow channel may have a cross-sectional width to depth ratio of 1.5 to 3.5, e.g., 2.0 to 3.0, over a partial or full length. For example, the microfluidic channel may have a width to depth ratio of 1.5 to 3.5 over at least a majority of the section, e.g. over 80% or more of the full length of the microfluidic channel upstream of the detection zone.

In some embodiments, the microfluidic channel may have a hydrophilic surface, in particular may have a hydrophilic surface over the entire length.

The above-mentioned individual features and the individual features to be mentioned below and the features which can be derived from the drawing can be combined with one another at will, as long as the individual features combined with one another are not mutually contradictory.

Drawings

The invention will be described in more detail below by way of exemplary embodiments with reference to the accompanying drawings, to which the invention is not limited. Wherein:

fig. 1 is a schematic circuit diagram of a sampling device according to one embodiment of the present invention.

Fig. 2 is a schematic structural plan view of the sampling device of fig. 1.

Fig. 3 is a high profile of a fluid flowing in a microfluidic channel of the sampling device of fig. 1.

Fig. 4 is a schematic vertical cross-section of the sampling device of fig. 1 along the microfluidic channel.

Fig. 5a is a schematic vertical cross-section of an embodiment of the detection zone of the sampling device.

Fig. 5b is a schematic vertical cross-section of another embodiment of the detection zone of the sampling device.

Fig. 6 is a schematic partial top view of an entrance region of a detection zone of a sampling device according to one embodiment.

Detailed Description

Fig. 1 is a schematic circuit diagram of a sampling device according to an embodiment of the present invention, and fig. 2 is a schematic structural plan view of the sampling device of fig. 1. In fig. 2, the sampling device is depicted in the form of a transparent view, and thus the microfluidic flow channel inside the sampling device can be seen in fig. 2. Fig. 3 is a high profile of a fluid flowing in a microfluidic channel of the sampling device of fig. 1, and fig. 4 is a schematic vertical cross-section of the sampling device of fig. 1 running along the microfluidic channel. In fig. 3 and 4, the lengths of the individual sections of the microfluidic channel are not drawn to scale so that the individual sections of the microfluidic channel may be better described.

The sampling device may be configured as a planar element, for example an elongate, annular or circular planar element. In the embodiment shown, the planar element is formed as a rectangular sheet-like component. The sampling device may comprise a sample inlet 1, which may be configured as an annular collar protruding from the planar element. The biological fluid sample to be detected may be added to the sample inlet 1, for example by means of a pipette. Preferably, the sampling device can have a single sample inlet 1. The microfluidic flow channels may in principle have any cross-sectional shape, however a broad shallow cross-section is preferred.

The sampling device may comprise a microfluidic flow channel connected to said sample inlet 1 for inputting a biological fluid sample. Downstream of the sample inlet 1, an embedding section 2 containing reagents for processing a biological fluid sample may be provided in the microfluidic flow channel. Optionally, a first micro valve 8 may be provided between the sample inlet 1 and the embedding part 2 for controlling the flow rate of the biological fluid sample.

The microfluidic channel may comprise a mixing section 3, in which mixing section 3 the biological fluid sample may be mixed with the reagents.

The embedding part 2 can be partially or completely integrated into the mixing section 3. In some embodiments, all of the reagents may be centrally embedded in one reagent-concentrating embedding section upstream of the mixing section 3. In other words, the embedding part 2 can be formed completely separately from the mixing section 3. In some embodiments, all of the reagents may be dispersed embedded in the mixing section 3, for example, may be dispersed embedded in the first subsection 30 of the mixing section 3. In other words, the embedding part 2 can be completely integrated in the mixing section 3. In the embodiment shown in fig. 2, a part of the reagents may be centrally embedded in one reagent-concentrating embedding part 2a, which reagent-concentrating embedding part 2a is upstream of the mixing section 3, and the remaining reagents may be dispersedly embedded in the mixing section 3. In other words, the mixing section 3 constitutes the reagent dispersing embedding part 2b. The portion of the reagent may be, for example, a small portion of the reagent, e.g., 30% of the total reagent, and the remaining reagent may be a large portion of the reagent, e.g., 70% of the total reagent. When the biological fluid sample inputted from the sample inlet 1 flows through the reagent concentration embedding part 2a, the reagent contained in the reagent concentration embedding part 2a is added to, for example, dissolved in the biological fluid sample. Then, when the biological fluid sample carrying the reagent from the reagent concentration embedding part 2a flows through the mixing section 3, the reagent received in the mixing section 3 or in the reagent dispensing embedding part 2b is also added to the biological fluid sample. In the mixing section, the reagent is sufficiently dissolved into and mixed with the biological fluid sample.

As shown in fig. 3 and 4, the bottom surfaces of the embedding part 2 and the mixing section 3 are lowered in height in relation to the bottom surface of the injection port 1, wherein the bottom surfaces of the sections upstream of the embedding part 2 can be kept constant in height and the bottom surfaces of the embedding part 2 and the mixing section 3 can be kept constant in height. In some embodiments, the bottom surface of the reagent concentrating embedding part 2a may be lowered in height relative to the bottom surface of the sample inlet 1, and the bottom surface of the mixing section 3 may remain unchanged or be lowered in height relative to the bottom surface of the reagent concentrating embedding part 2 a. By the measures, the height difference between the sample inlet 1 and the embedding part 2 and/or the mixing section 3 can be formed, and the biological fluid sample flows through the embedding part 2 and the mixing section 3 at a high flow rate under the action of gravity, so that the dissolution, diffusion, mixing and/or reaction of the reagent in the biological fluid sample can be promoted.

In an embodiment not shown, the bottom surface of the section of the microfluidic channel between the sample inlet 1 and the output of the mixing section 3 may be continuously lowered.

In an embodiment not shown, the bottom surface of the section of the microfluidic channel from the sample inlet 1 to a point of the mixing section 3 may continuously descend and the bottom surface of the section of the microfluidic channel from said point of the mixing section 3 to the output of the mixing section 3 may continuously rise.

In order to save space, the mixing section 3 can be designed in a meandering manner. As shown in fig. 2, the mixing section 3 may comprise three substantially parallel subsections 30. By the overlapping arrangement of the three subsections in the width direction of the sampling device, the length dimension of the sampling device can be minimized.

To promote the mixing effect, the mixing section 3 may have at least one structure selected from the group of: a bending part 31, a reducing part 32 and a microcolumn. As shown in fig. 2, each subsection 30 of the mixing section 3 may have a plurality of bends 31 and a plurality of diameter variations 32. These bending portions 31 may have a bending angle in the range of 60 ° to 120 °, for example, about 90 °. Both the bent portion 31 and the variable diameter portion 32 can promote the generation of vortex in the flowing biological fluid sample, while the biological fluid sample can flow through the bent portion 31 and the variable diameter portion 32 at a high flow rate due to the action of gravity and collide with the side walls at the bent portion 31 and the variable diameter portion 32, thereby further promoting the generation of vortex. Thus, the combined action of the bend 31 and the variable diameter portion 32 and the height head promotes the mixing of the reagent with the biological fluid sample.

As shown in fig. 4, the embedding part 2 and the mixing section 3 may have a bottom surface at the same height and a top surface at the same height, and thus may have the same depth. The embedding part 2, the mixing section 3 and the section between the sample inlet 1 and the embedding part 2 may have top surfaces at the same height. The embedding part 2, the mixing section 3 and the section between the sample inlet 1 and the embedding part 2 may have a width that remains unchanged.

Downstream of the mixing section 3, the microfluidic flow channel may have a buffer section 4. As shown in fig. 4, the bottom surface of the buffer section 4 can rise in height with respect to the bottom surface of the mixing section 3. The buffer section 4 may have the same or different depth as the mixing section 3. A bend 41 may be provided in the buffer section 4. As shown in fig. 2, a single bend 41 may be provided in the buffer section 4. Alternatively, a plurality of bends may also be provided in the buffer section 4. The bend may have a bend angle of, for example, 60 ° to 120 °, preferably about 90 °. The curved portion 41 can improve the flow resistance. The elevation of the bottom surface of the buffer section 4 relative to the bottom surface of the mixing section 3 in height, the bend 41 in the buffer section 4 may help the biological fluid sample to have a suitably reduced flow rate when exiting the buffer section 4.

As shown in fig. 4, the buffer section 4 has approximately the same depth as the mixing section 3, wherein the bottom surface of the buffer section 4 rises in a jump with respect to the bottom surface of the mixing section 3, and the top surface of the buffer section 4 rises in a jump with respect to the top surface of the mixing section 3.

In an embodiment not shown, the buffer section 4 and the mixing section 3 have different depths, wherein the bottom surface of the buffer section 4 rises in a jump with respect to the bottom surface of the mixing section 3, but the top surface of the buffer section 4 is at the same level as the top surface of the mixing section 3. The buffer section 4 may have the same or different width as the mixing section 3.

In a further embodiment, the bottom surface of the buffer section can at least partially continuously rise in the flow direction of the fluid, wherein the bottom surface of the buffer section at the inlet end can smoothly transition from the bottom surface of the mixing section at the outlet end.

Optionally, a second micro valve 9 may be provided in the mixing section 4 for controlling the flow rate of the fluid.

Downstream of the buffer section 4, the microfluidic flow channel may have a detection zone 5. Downstream of the detection zone 5 a waste liquid section 6 and a vent 7 may be provided. Air displaced by the flow of biological fluid sample mixed with the reagent may be expelled from the vent 7. It is for example possible to carry out visual detection of the biological fluid sample in the detection zone 5 or to carry out fluorescent detection or glow detection with special equipment.

The detection zone 5 may be configured as a planar area. As shown in fig. 4, the bottom surface of the input end of the detection zone 5 may be at the same height as the bottom surface of the output end of the buffer section 4. Alternatively, the bottom surface of the input end of the detection zone 5 may rise in height relative to the bottom surface of the output end of the buffer section 4. In an embodiment not shown, no buffer section 4 may be provided, wherein the bottom surface of the input end of the detection zone 5 may rise in height relative to the bottom surface of the mixing section 3. By raising the bottom surface of the input end of the detection zone 5 in height relative to the bottom surface of the output end of the mixing section 3 or the bottom surface of the output end of the buffer section 4, the flow rate of the fluid entering the detection zone 5 from the input end of the detection zone 5 can be reduced to a suitable flow rate by gravity, whereby a uniform spreading of the biological fluid sample in the detection zone 5 can be promoted.

In an embodiment not shown, the microfluidic channel may have a continuously decreasing bottom surface in the section from the sample inlet 1 to the output of the buffer section 4 and may have a jump-rising bottom surface in the detection zone 5 (this may be the same or similar as in the embodiment shown in fig. 5a, which will be described in more detail). The microfluidic channel may have a flow length of 80 to 200mm, in particular 100 to 160mm, for example 120 to 150mm, in the section from the sample inlet 1 to the output of the buffer section 4. The microfluidic channel may have a drop of 1-4 mm, in particular 2-3 mm, for example about 2.5mm, between the sample inlet 1 and the deepest point in the section from the sample inlet 1 to the output of the buffer section 4.

In an embodiment not shown, the microfluidic channel may have a constant depth in the section from the sample inlet 1 to the output of the buffer section 4, wherein preferably the microfluidic channel may have a substantially constant first width before the buffer section 4 and an increasing second width in the buffer section.

Fig. 5a and 5b are schematic vertical sectional views of two different embodiments of the detection zone 5 of the sampling device, which may also be combined with each other. In both embodiments, the detection zone 5 may have a reduced depth in the central region compared to the two ends, with reference to the flow direction of the biological fluid sample, whereby the creation of dead zones, in which bubbles may be present, may be further prevented. Thus, the depth L of the detection zone 5 in the central region is smaller than the depth H at both ends, e.g. the depth L may be approximately half the depth H. In the embodiment shown in fig. 5a, the detection zone 5 may have a boss 51 protruding from the bottom surface in the central region, the depth L of the detection zone 5 in the central region being <0.2mm. In the embodiment shown in fig. 5b, the detection zone 5 may have a boss 52 protruding from the top surface in the central region, the depth L of the detection zone 5 in the central region being ≡0.2mm. By reducing the depth L of the detection zone 5 in the central region compared to the depth H at both ends, the flow resistance of the fluid flowing through the central region can be improved, and uniform spreading of the fluid in the detection zone 5 can be promoted.

As shown in fig. 2 and as shown in fig. 6, the side wall of the detection zone 5 in the inlet region transitions from both ends to the central region in a curved fashion with reference to the flow direction of the fluid. The curve may be, for example, a spline curve. The shape of the curve may be selected such that the fluid is able to flow in the detection zone 5 substantially uniformly spread out so that no dead zone is formed in the detection zone 5. As shown in fig. 6, the two sidewalls may be symmetrical, and the width defined by the two sidewalls may be initially incrementally increased and then incrementally decreased, in other words, the first derivative of the width may be initially increased and then decreased. In fig. 6, four

fluid fronts

11, 12, 13, 14 are also schematically depicted, which occur in succession, wherein the fluid fronts are depicted alternately with solid and dashed lines. It follows that by design of the side wall shape of the inlet region of the detection zone the fluid front is gradually flattened and thus a good detection of the fluid in the detection zone 5 can be achieved.

In the embodiment shown, the microfluidic channel may have a substantially rectangular cross section upstream of the detection zone 5. The ratio of the width to the depth of the cross section of the microfluidic flow channel upstream of the detection zone in at least a partial section, e.g. in the majority of the section or over the full length, may be in the range of 1.5 to 3.5, e.g. in the range of 2.0 to 3.0.

It is to be noted here that the height variation shown in fig. 4 is merely illustrative. The expressions "ascending in height" and "descending in height" as used in the present invention relate to one or more height change steps, i.e. there may be only one single level of height change between two areas, or there may be multiple levels of height change, or there may be continuous height change. The transition between the various height-varying steps depicted in fig. 3 is merely illustrative. The transition between the height-varying steps can be in the form of a curve.

The microfluidic flow channel may have a hydrophilic surface. The sampling device may be constituted, for example, by a first sheet and a second sheet superimposed on each other, wherein the structure of the microfluidic flow channel may be made in at least one of the first sheet and the second sheet. The second sheet is bonded, e.g., glued or welded, to the first sheet in a material-locking relationship. Each sheet may be made of, for example, silicon wafer or Polydimethylsiloxane (PDMS).

Self-driving forces may be derived primarily from gravitational potential, capillary forces and surface tension forces. The effect of surface tension (adhesion, compression) can be more pronounced at the microscale. The main dimensionless numbers affecting the fluid movement in the fluidic channel are reynolds number Re, weber number Wb, capillary number Ca, etc., and the main factors may include wall wettability and viscosity ratio between liquids. Here, the formula ca=μv/γ can be applied, where μ is the measured viscosity kg/(m·s) of the fluid, v is the average linear flow rate (m/s) of the fluid, and γ is the tension coefficient. When Ca value is 10 ^-4 ～10 ^-1 Capillary action may be evident between.

Thickness e-wCa of liquid film between fluid and flow channel wall ^2/3 I.e. the cross-sectional width of the flow channel and the capillary number Ca.

The wall of the micro-channel faces the liquid and has different infiltration characteristics, mainly the influence of surface hydrophilicity/hydrophobicity on sliding. Surface hydrophilicity/hydrophobicity is related to the solid surface, i.e. to the strength of the interaction between liquid and solid molecules. For hydrophilic surfaces, the contact angle θ >90 °, the stronger liquid-solid phase interaction would limit the slip of the liquid, while for hydrophobic surfaces, the contact angle θ <90 °, the opposite is true.

When the reagent reacts with the test fluid, its transport process is in an unbalanced state, which eventually brings its distribution to equilibrium. In the present system, the accompanying flow phenomena include mainly velocity and concentration of the substance, and thus the transfer process includes mainly momentum transfer and mass transfer, which are caused by irregular movement of the molecules. The location and manner of embedding the reagent is primarily adjusted according to the molecular diffusion coefficient of the reagent itself. The flow rate of the diffusion substance per unit time through a unit cross-sectional area perpendicular to the diffusion direction (referred to as diffusion flux indicated by J) is proportional to the concentration gradient at that cross-section, that is, the larger the concentration gradient, the larger the diffusion flux. The formula applies here:

Wherein D is called the diffusion coefficient (m ² S) and C is the volume concentration (atomic number/m) of the diffusion substance (component) ³ Or kg/m ³ )，/>

For the concentration gradient, "-" indicates that the diffusion direction is the opposite direction of the concentration gradient, i.e., the diffusion component diffuses from the high concentration region to the low concentration region. The unit of the diffusion flux J is kg/(m) ² ·s)。

A typical feature of flow at the microscale is the very low reynolds number Re of the flow, which is mostly in the laminar regime, and laminar un-blended flow causes mixing difficulties. Here, through the structural design of micro-fluidic, can utilize special passageway geometry to realize the repeated segmentation of fluid, tensile, distortion or folding under low reynolds number to increase the contact probability between the parallel flow layer originally, realize promoting the effect of mixing. In the curved flow path, the flow velocity near the inner wall surface and near the outer wall surface is asymmetric due to the change of the curvature radius of the path, so that the change of flow shear is induced, and the size of the flow vortex inside the fluid is changed. The vortex sizes at the two sides of the inner wall and the outer wall of the continuous reducing bend can be changed alternately, so that the fluid at the upper half part and the fluid at the lower half part can be exchanged and mixed. The Z-bend also reverses the direction of swirl within the fluid, which may better achieve thorough mixing of the components within the fluid.

The fluid can select the path with the minimum flow resistance in the process of moving the micro-channel network, the fluid can increase the flow resistance of the path where the fluid is positioned, the path selection of the subsequent fluid is influenced, and nonlinear effect and edge detection slippage are caused in the original linear low-Reynolds-number Stokes flow. Thereby inducing the phenomena of uneven flatness, bubbles and the like in the detection area to influence the effectiveness and accuracy of detection. As the diameter (cross section) of the pipe decreases, the flow resistance in the pipe increases sharply. Therefore, different transition structures are required to achieve the effect of uniform expansion of the detection zone at different pipe diameters (cross sections).

The sampling device according to the invention can be used, for example, in molecular biology experiments, in particular in chemiluminescent applications. The biological fluid sample to be detected can be added from the sample inlet 1, and is advanced by self-driving force, reacts with the embedded reagent, is uniformly mixed by the mixing section, and then enters the detection area for detection. Here, the microfluidic channel may be continuously hydrophilic. The embedding part 2 may be formed, for example, in such a way that a dissolved reagent (chemical reagent, enzyme, antibody, nucleic acid or the like) may be coated in a microfluidic flow channel and subsequently dried at the time of manufacturing the sampling device. Typically, dry chemical reagents used as validation reagents (e.g., as indicators) may be stored.

Application example 1: an infectious disease in a urine sample fluid is determined.

The embedding part 2 of the sampling device may contain detection reagents for the enzymatic verification of leukocytes, nitrites, albumin, occult blood and creatinine. In the case of the presence of the corresponding analyte in the liquid sample to be measured, the liquid sample to be measured is determined to be fed into the sample inlet 1 by means of a pipette or a sample injection needle, the sample enters the sampling device and flows through the embedding part 2 to react with the corresponding reagent, and then continues to pass through the mixing section 3 under the action of capillary force and fluid surface tension and gravity to the detection zone 5. The detection zone 5 may be entirely transparent, where the sample liquid may be analyzed by eye and chromaticity or by illumination techniques. And the level of the corresponding analyte in the sample fluid can be determined by the standard curve of the standard.

Application example 2: glucose in serum was determined.

The glucose content in serum can be determined by chemiluminescence. The glucose is enzymatically oxidized to gluconic acid by glucose oxidase and hydrogen peroxide is released. Luminol (3-aminobenzene dihydrazide) can be oxidized by an oxidizing agent such as hydrogen peroxide in an alkaline medium to emit light with a wavelength of about 425 nm. The reaction may be catalyzed by a number of metal ions. The chemiluminescent intensity is proportional to the concentration of hydrogen peroxide produced (i.e., to the concentration of glucose) and can be measured by conventional photosensitive sensors. By measuring the luminescence intensity of the glucose standard solution and the plasma sample, the glucose content of the serum can be obtained by comparison.

In this application, the reagent or reagents are embedded in dry form in the embedding part 2 of the sampling device. For example, glucose oxidase may be pre-embedded in a first reagent-embedded zone and a biological fluid sample composed of luminol, potassium ferricyanide and sodium hydroxide alkaline solution placed in a second reagent-embedded zone downstream. During detection, a certain volume of serum can be added into the sample inlet 1 by using a pipette, a sample enters the sampling device, and a dry chemical reagent contained in the first reagent embedding region can be dissolved and react with the sample. Glucose in serum is oxidized by glucose oxidase to gluconic acid and hydrogen peroxide at neutral pH, and then the sample enters the second reagent embedding region and reacts with the embedded luminol, potassium ferricyanide and alkaline reagent. The fluid to be detected is then further reacted and mixed thoroughly via the mixing section 3, wherein the reaction time can be precisely adjusted by the capillary cross section of the mixing section 3 and its surface properties. The reacted sample then continues to flow into the detection zone 5 and is measured at the detection zone 5 by an external photomultiplier, thereby generating an optical signal. The glucose content in the serum can be determined from the intensity of the generated optical signal.

Application example 3: and determining gonad-related detection items (sandwich immunodetection) such as chorionic gonadotrophin and the like in serum. The sampling device may function similarly in such applications.

The sampling device according to the invention can be used in cell biology experiments, such as cell counting and detecting cell viability.

Application example 4: wall-attached growth cell count and cell viability (e.g., HEK293 cells).

HEK293 cells were cultured in a carbon dioxide incubator with 5% CO using DMEM medium containing 10% fetal bovine serum ₂ And (3) standing and culturing at 37 ℃. When the cells are grown to a certain stage, e.g., cell confluence around 50%, cell digestion is performed using trypsin and cell resuspension is performed using DMEM medium. The resuspended cells are uniformly mixed and added into a sample feeding tube and placed at an instrument sample inlet, the instrument automatically adds the samples into a sampling device for embedding AO (acridine orange) and PI (propidium iodide) dyes through a pipetting system, and an instrument imaging system and software are used for counting and evaluating the activity of the samples. Wherein AO can intercalate into the nuclei of all cells (living and dead cells) through intact cell membranes; PI can only pass through incomplete cell membranes, intercalating into the nuclei of all dead cells. When viewed using a fluorescence device, AO stained cells exhibited green fluorescence and PI stained cells exhibited red fluorescence. When two dyes exist in the nucleus, under the proper ratio of AO and PI, the two dyes generate energy resonance transfer, so that living cells excite green fluorescence under a blue channel, and dead cells excite red fluorescence under a green channel. AO and PI can immediately stain HEK293 cells and determine viable, dead and total cells based on staining. According to the staining conditions of the AO and PI combined cells, the sampling device can accurately judge the cell concentration and the activity rate.

Application example 5: cell viability was counted and examined for adherent growth using trypan blue as an embedding dye (e.g., HEK293 cells). In this application, the sampling device according to the invention may be operated similarly.

Trypan blue is a blue acid dye containing two azo chromophores, a large, hydrophilic and tetrasulfonated anionic dye, which can be used universally to detect cell membrane integrity and assess cell viability. Living cells are not stained, whereas dead cells take up dye, so living cells that are not stained and dead cells that are blue stained can be counted separately. The trypan blue can immediately dye HEK293 cells, and the total cells are identified according to the analysis of bright field imaging results, and living cells and dead cells are judged according to the dyeing condition. The sampling device can accurately judge the cell concentration and the activity rate.

As other examples, the sampling device according to the invention may also be used in suspension growth cell counting and cell viability assays, in cell transfection, in apoptosis assays, in antigen detection and quantification, and in antibody affinity assays and quantification.

It is noted that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that the terms "comprises" and "comprising," and other similar terms, when used in this specification, specify the presence of stated operations, elements, and/or components, but do not preclude the presence or addition of one or more other operations, elements, components, and/or groups thereof. The term "and/or" as used herein includes all arbitrary combinations of one or more of the associated listed items. In the description of the drawings, like reference numerals always denote like elements.

Finally, it is pointed out that the above embodiments are only intended to understand the invention and do not limit the scope of protection thereof. Modifications to the above would be obvious to those of ordinary skill in the art, but would not bring the invention so modified beyond the scope of the present invention.

Claims

1. A sampling device, characterized in that the sampling device comprises a microfluidic flow channel having a sample inlet (1) for inputting a biological fluid sample, an embedding (2) downstream of the sample inlet containing a reagent for processing the biological fluid sample, a mixing section (3) for mixing the biological fluid sample with the reagent, a detection zone (5) downstream of the mixing section, a waste liquid section (6) downstream of the detection zone and a vent (7), the microfluidic flow channel being configured such that a fluid can flow in the microfluidic flow channel from the sample inlet to the detection zone by a self-driving force consisting of the gravitational potential, the surface tension and the capillary force of the fluid, wherein the high-level trend of the bottom surface of the microfluidic channel is configured such that the fluid is accelerated by the gravitational potential of the fluid over at least part of the section of the microfluidic channel between the sample inlet and the output of the mixing section and such that the fluid is decelerated by the gravitational potential of the fluid again before reaching the input end of the detection zone of the microfluidic channel;

The bottom surface of the embedding part and/or the mixing section is lowered in height relative to the bottom surface of the sample inlet; and the bottom surface of the embedding and/or mixing section remains unchanged in height along the flow direction of the fluid, or the bottom surface of the embedding and/or mixing section descends continuously at least partially along the flow direction of the fluid; and the depth of the embedding portion and/or mixing section remains the same or increases relative to the depth of the section of the microfluidic channel between the sample inlet and the embedding portion;

the microfluidic channel has a buffer section (4) arranged between the mixing section and the detection section for buffering the fluid before entering the detection section, the bottom surface of the buffer section rising in height with respect to the bottom surface of the mixing section and the bottom surface of the input end of the detection section rising in height with respect to the bottom surface of the output end of the buffer section or being at the same height as the bottom surface of the output end of the buffer section; and is also provided with

The detection zone is configured as a planar zone, wherein the detection zone has an increased width dimension and a reduced depth in the central zone compared to the two ends, and the side wall of the detection zone in the inlet zone transitions to the central zone in the form of a curve, the shape of which is selected such that the fluid can flow in the detection zone substantially uniformly spread out, wherein in the inlet zone of the detection zone the width of the detection zone is first incrementally increased and then incrementally increased.

2. The sampling device of claim 1, wherein the embedding portion is partially or fully integrated into the mixing section.

3. The sampling device according to claim 2, characterized in that the embedding part comprises a reagent concentration embedding part (2 a) upstream of the mixing section and/or a reagent dispersion embedding part (2 b) integrated in the mixing section.

4. A sampling device according to any one of claims 1 to 3, wherein the top surface of the section of the microfluidic channel from the sample inlet to the output of the mixing section remains unchanged in height.

5. A sampling device according to any one of claims 1 to 3, wherein the bottom surface of the buffer section is rising in transitions at the input end of the buffer section relative to the bottom surface of the output end of the mixing section.

6. A sampling device according to any one of claims 1 to 3, wherein the bottom surface of the buffer section rises continuously at least partially along the direction of fluid flow.

7. A sampling device according to any one of claims 1 to 3, wherein the buffer section has a bend (41).

8. A sampling device according to any one of claims 1 to 3, wherein the microfluidic channel has a continuously descending floor in a section from the sample inlet to the output of the buffer section and a jump ascending floor in the detection zone.

9. A sampling device according to any one of claims 1 to 3, wherein the microfluidic channel has a constant depth in a section from the sample inlet to the output of the buffer section, wherein the microfluidic channel has a first width before the buffer section and a second width in the buffer section that is increased compared to the first width.

10. A sampling device according to any one of claims 1 to 3, wherein the microfluidic channel has a flow length of 100 to 160mm in the section from the sample inlet to the output of the buffer section and a drop of 2 to 3mm between the sample inlet and the deepest point in the section from the sample inlet to the output of the buffer section.

11. A sampling device according to any one of claims 1 to 3, wherein the buffer section is configured for allowing fluid to resume a laminar flow condition in the buffer section.

12. A sampling device according to any one of claims 1 to 3, characterized in that a first micro valve (8) for controlling the flow rate of the fluid is provided between the sample inlet and the embedding part.

13. A sampling device according to any one of claims 1 to 3, wherein a second micro valve is provided in the buffer section for controlling the flow rate of the fluid.

14. A sampling device according to any one of claims 1 to 3, wherein the mixing section has at least one structure selected from the group: a bending part (31), a reducing part (32) and a microcolumn.

15. The sampling device according to claim 14, wherein the mixing section comprises a plurality of side-by-side subsections (30), each subsection having at least one structure selected from the group.

16. A sampling device according to any one of claims 1 to 3, wherein the detection zone has a boss (51) protruding from the bottom surface and/or a boss (52) protruding from the top surface in the central region.

17. A sampling device according to any one of claims 1 to 3, wherein the microfluidic flow channel has a cross-sectional width to depth ratio of 1.5 to 3.5 over a part or the whole length upstream of the detection zone.

18. A sampling device according to any one of claims 1 to 3, wherein the microfluidic flow channel has a ratio of width to depth of cross section over its entire length of 2.0 to 3.0 upstream of the detection zone.

19. A sampling device according to any one of claims 1 to 3, wherein the microfluidic channel has a hydrophilic surface.