CN113996355A

CN113996355A - Sampling device

Info

Publication number: CN113996355A
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: 2022-02-01
Anticipated expiration: 2041-10-28
Also published as: CN113996355B

Abstract

The invention relates to a sampling device comprising a microfluidic flow channel with a sample inlet (1) for the input of a biological fluid sample, an embedding section (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 zone (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 course of the height of the bottom surface of the microfluidic channel is configured such that the fluid has a higher flow velocity in the mixing section and reaches the detection zone at a lower flow velocity. The sampling device can be manufactured in a cost-effective manner, has a small number of parts and is reliable in operation.

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 a disposable consumable.

Background

Detection of biological fluid samples may be involved in life science research, biopharmaceuticals, medical diagnostics, and the like. The biological fluid sample may be, for example, human or animal blood, urine, body fluids, extracts of plants, which may be non-pretreated or pretreated. For example, the number of red blood cells, the number of white blood cells, the viability of cells, etc. may be measured for a whole blood sample. The detection of biological fluid samples may, for example, involve applications in molecular diagnostics, immunofluorescence assays, and fluorescent antibody technology.

Disclosure of Invention

It is an object of the present application 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 part 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 hole, the microfluidic flow channel is configured such that a fluid can flow from the sample inlet to the detection region in the microfluidic flow channel by a self-driving force consisting of a gravitational potential, a surface tension, and a capillary force of the fluid, wherein the trend of 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 to the output end of the mixing section, and the fluid is decelerated again by the gravitational potential of the fluid before reaching the input end of the detection zone of the microfluidic channel.

In the sampling device according to the present invention, the self-driving force is generated by the gravitational potential in addition to the surface tension and the capillary force, whereby different height differences can be set in the microfluidic flow channel as required, and the flow rate of the biological fluid sample can be appropriately adjusted. For example, with a reduced height of the embedding portion and/or the mixing section, dissolution and mixing of the embedded reagent in the fluid sample may be facilitated. The re-ascending height downstream of the mixing section then allows the fluid sample, mixed with the reagent, to enter the detection zone at a reduced flow rate, suitably to perform the detection.

In the sampling device according to the invention, the change in the gravitational potential leads to 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 spreads 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 section for buffering fluid before entering the detection section. The buffer section may reduce the flow rate of the fluid to be introduced into the detection zone and at the same time may reduce the eddy currents remaining in the fluid, which may promote a uniform spreading of the fluid in the detection zone.

In some embodiments, the embedding portion may be at least partially or completely integrated into the mixing section. Thereby, a suitable 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 concentration embedding portion that is upstream of the mixing section. In other words, the embedding is formed completely separately from the mixing section.

In some embodiments, all of the reagents may be dispersedly embedded in the mixing section, e.g., may be dispersedly embedded in the front 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 concentration embedding portion that is upstream of the mixing section, and the remaining reagents may be dispersedly embedded in the mixing section. The portion of the reagents may be, for example, a small portion of the reagents, such as 30% of the total reagents, and the remaining reagents may be a large portion of the reagents, such as 70% of the total reagents.

In some embodiments, the floor of the embedding portion and/or mixing section may be lowered in height relative to the floor of the injection port. Thereby, a height difference can be generated between the sample inlet and the embedding part, so that the flow speed of the biological fluid sample when reaching the embedding part is improved, and the dissolution and the diffusion of the reagent in the biological fluid sample are promoted.

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

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

In some embodiments, the bottom surface of the reagent concentration embedding portion may be lowered in height relative to the bottom surface of the injection port, and the bottom surface of the mixing section may remain constant or lowered in height relative to the bottom of the reagent concentration embedding portion.

Here, the biological fluid sample may flow in the mixing section at a higher flow rate, which may facilitate dissolution of the reagent in the biological fluid sample and efficient and sufficient mixing of the biological fluid sample and the reagent.

In some embodiments, the depth of the embedding and/or mixing section may be constant or increased relative to the depth of the section of the microfluidic channel between the sample inlet and the embedding.

In some embodiments, the top surface of the section of the microfluidic channel between the sample inlet to the output end of the mixing section may remain constant 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. Therefore, the flow speed of the biological fluid sample when reaching the detection area can be reduced, and the biological fluid sample can be promoted to be uniformly spread in the detection area.

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

In some embodiments, the bottom surface of the buffer section may rise at the input end of the buffer section in a step-like manner relative to the bottom surface of the output end of the mixing section.

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

In some embodiments, the bottom surface of the input end of the detection zone may be raised in height relative to or 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 promoted.

In some embodiments, the relief section may have a bend. The bend may increase the flow resistance, thereby achieving a further reduction in fluid flow rate in addition to the height drop 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 °, for example 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 not have a buffer section, wherein the mixing section may be directly connected to the detection zone.

In some embodiments, the floor of the mixing section can descend in an upstream first section and ascend again in a downstream second section, in particular immediately downstream of the first section. Thus, the fluid may achieve mixing 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 microvalve for controlling a flow rate of a fluid may be disposed between the sample inlet and the embedding portion. The appropriate 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 disposed 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 microvalve 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: a bending part, a diameter-changing part and a microcolumn. The structure can promote the generation of vortex flow in the mixing section of the biological fluid sample, and therefore promote the uniform mixing of the reagent in the biological fluid sample.

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

In some embodiments, each sub-section may have a plurality of bends and a plurality of diameter sections.

In some embodiments, each of the bent portions may have a bending angle of 20 ° to 160 °, for example, a bending angle of 30 ° to 150 °, and preferably a bending angle of 45 ° to 120 °.

In some embodiments, the microfluidic channel may have a continuously descending floor in a section from the sample inlet to the output end of the buffer section, and/or a floor that rises abruptly 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 end 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 can have a flow path length of 80-200 mm, such as 100-160 mm, in a section from the sample inlet to the output end of the buffer section, and/or a drop height of 1-4 mm, such as 2-3 mm, between the sample inlet and the deepest point in a section from the sample inlet to the output end of the buffer section.

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

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 direction of flow of the fluid. This prevents dead spaces from forming in the detection zone, which could not be reached by the biological fluid sample, and in which air bubbles can form.

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

In some embodiments, the side wall of the detection zone in the inlet region may transition in a curved manner to the central region with reference to the flow direction of the fluid, the shape of the curve being selected such that the fluid can flow in the detection zone substantially uniformly spread out. Thereby, a uniform spreading of the fluid in the detection zone may further be achieved and the formation of dead zones in the detection zone may further be prevented.

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

In some embodiments, the microfluidic flow channel may have a cross-sectional width to depth ratio of 1.5 to 3.5, such as 2.0 to 3.0, over a partial segment or the entire length upstream of the detection zone. For example, upstream of the detection zone, the microfluidic flow channel may have a cross-sectional width to depth ratio of 1.5 to 3.5 over at least a majority of the segment, for example over more than 80% of the total length of the microfluidic channel upstream of the detection zone.

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

The individual features mentioned above and those yet to be mentioned below and those which can be derived from the drawings can be combined with one another as desired, provided that the individual features combined with one another are not mutually inconsistent.

Drawings

The invention is explained in more detail below with reference to the drawing by means of exemplary embodiments, without however being restricted thereto. 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 height 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 running along a microfluidic channel.

FIG. 5a is a schematic vertical cross-sectional view of one embodiment of a detection zone of a sampling device.

FIG. 5b is a schematic vertical cross-sectional view of another embodiment of a detection zone of a sampling device.

Fig. 6 is a schematic partial top view of an inlet 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 drawing, and thus the microfluidic flow channels inside the sampling device can be seen in fig. 2. Fig. 3 is a height profile of a fluid flowing in a microfluidic channel of the sampling device of fig. 1, and fig. 4 is a schematic vertical sectional view of the sampling device of fig. 1 running along the microfluidic channel. In fig. 3 and 4, the lengths of the various sections of the microfluidic channel are not drawn to scale so that the various sections of the microfluidic channel may be better described.

The sampling device can be designed as a planar element, for example as an elongated, circular or circular planar element. In the embodiment shown, the planar element is designed 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 can be added to the sample inlet 1, for example by means of a pipette. Preferably, the sampling device can have one single sample inlet 1. The microfluidic flow channel may in principle have any cross-sectional shape, however a broad and shallow cross-section is preferred.

The sampling device may comprise a microfluidic flow channel connected to said sample inlet 1 for the input of a biological fluid sample. Downstream of the sample inlet 1, an embedding part 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 portion 2 for controlling the flow rate of the biological fluid sample.

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

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 concentration embedding part, which is upstream of the mixing section 3. In other words, the embedding portion 2 can be formed completely separately from the mixing section 3. In some embodiments, all of the reagents may be dispersedly embedded in the mixing section 3, for example, may be dispersedly 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 concentratedly embedded in one reagent concentration embedding portion 2a, the reagent concentration embedding portion 2a being upstream of the mixing section 3, and the rest of the reagents may be dispersedly embedded in the mixing section 3. In other words, the mixing section 3 constitutes the reagent dispersion embedding portion 2 b. The portion of the reagents may be, for example, a small portion of the reagents, such as 30% of the total reagents, and the remaining reagents may be a large portion of the reagents, such as 70% of the total reagents. When the biological fluid sample inputted from the sample inlet 1 flows through the reagent concentration embedding portion 2a, the reagent contained in the reagent concentration embedding portion 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 portion 2a flows through the mixing section 3, the reagent received in the mixing section 3 or the reagent dispersion embedding portion 2b is also added to the biological fluid sample. In the mixing section, the reagent is fully 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 stepped down in height relative to the bottom surface of the injection port 1, wherein the bottom surface of the section 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 concentration embedding part 2a may be lowered in height relative to the bottom surface of the injection port 1, and the bottom surface of the mixing section 3 may be kept constant or lowered in height relative to the bottom surface of the reagent concentration embedding part 2 a. By the above measures, a height difference exists between the sample inlet 1 and the embedding part 2 and/or the mixing section 3, 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 end of the mixing section 3 may continuously descend.

In an embodiment not shown, the bottom surface of the section of the microfluidic channel between the sample inlet 1 and a location of the mixing section 3 may continuously descend and the bottom surface of the section of the microfluidic channel between said location of the mixing section 3 and the output end of the mixing section 3 may continuously ascend.

In order to save space, the mixing section 3 can be designed meandering. As shown in fig. 2, mixing section 3 may include three generally 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 consisting of: a bending part 31, a diameter-changing part 32 and a microcolumn. As shown in fig. 2, each sub-section 30 of the mixing section 3 may have a plurality of bends 31 and a plurality of diameter-changing portions 32. These bends 31 may have a bend angle in the range of 60 ° to 120 °, for example, about 90 °. The bending part 31 and the variable diameter part 32 can promote the generation of the eddy current in the flowing biological fluid sample, and the biological fluid sample can flow through the bending part 31 and the variable diameter part 32 at a high flow rate due to the gravity and collide with the side wall at the bending part 31 and the variable diameter part 32, so that the generation of the eddy current is further promoted. Therefore, the combined action of the bending portion 31, the reducing portion 32 and the height difference promotes the uniform mixing of the reagent and the biological fluid sample.

As shown in fig. 4, the embedding part 2 and the mixing section 3 can have a bottom surface at the same height and a top surface at the same height and can therefore have the same depth. The embedding part 2, the mixing section 3 and the section between the injection port 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 injection port 1 and the embedding part 2 may have a width that remains constant.

Downstream of the mixing section 3, the microfluidic flow channel may have a buffer section 4. As shown in fig. 4, the bottom of the buffer section 4 can rise in a step-like manner in height relative to the bottom of the mixing section 3. The buffer section 4 may be of the same or different depth than the mixing section 3. A bend 41 may be provided in the buffer section 4. As shown in fig. 2, a single bend 41 can be provided in the buffer section 4. Alternatively, several bends may also be provided in the buffer section 4. The bent portion may have, for example, a bending angle of 60 ° to 120 °, preferably a bending angle of about 90 °. The bent portion 41 may increase flow resistance. The elevation in height of the bottom surface of the buffer section 4 relative to the bottom surface of the mixing section 3 and the bend 41 in the buffer section 4 may contribute to a suitably reduced flow rate of the biological fluid sample upon exiting the buffer section 4.

As shown in fig. 4, the buffer zone 4 and the mixing zone 3 have approximately the same depth, wherein the bottom of the buffer zone 4 rises in a step-like manner with respect to the bottom of the mixing zone 3, and the top of the buffer zone 4 rises in a step-like manner with respect to the top of the mixing zone 3.

In a non-illustrated embodiment, the buffer zone 4 and the mixing zone 3 have different depths, wherein the bottom surface of the buffer zone 4 rises in a step-like manner relative to the bottom surface of the mixing zone 3, but the top surface of the buffer zone 4 is at the same height as the top surface of the mixing zone 3. The buffer section 4 may be of the same or different width as the mixing section 3.

In a further embodiment, the bottom surface of the mixing section at the outlet end may be at least partially continuous in the flow direction of the fluid, wherein the bottom surface of the mixing section at the inlet end may smoothly transition into the bottom surface of the buffer section at the outlet end.

Optionally, a second microvalve 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 zone 6 and a vent 7 may be provided. Air displaced by the flow of the biological fluid sample mixed with the reagent may be vented through vent 7. It is for example possible to carry out a visual detection of the biological fluid sample in the detection zone 5 or to carry out a fluorescence or glow detection with a dedicated device.

The detection region 5 can be configured as a planar region. As shown in fig. 4, the bottom surface of the input end of the detection area 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 area 5 may rise in height relative to the bottom surface of the output end of the buffer section 4. In a not shown embodiment, the buffer section 4 may not 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 making the bottom surface of the input end of the detection zone 5 rise 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 an appropriate flow rate by gravity, so that the 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 descending floor in a section from the sample inlet 1 to the output end of the buffer section 4 and may have a floor that rises abruptly in the detection section 5 (this may be the same or similar as in the embodiment shown in fig. 5a, which will be explained in more detail). The microfluidic channel may have a flow path length of 80-200 mm, in particular 100-160 mm, for example 120-150 mm, 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, particularly 2-3 mm, for example about 2.5mm, between the injection port 1 and the deepest point in the section from the injection port 1 to the output end of the buffer section 4.

In an embodiment not shown, the microfluidic channel may have a constant depth in a section from the sample inlet 1 to the output end 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 cross-sections of two different embodiments of the detection area 5 of the sampling device, which can also be combined with each other. In both embodiments, the detection zone 5 may have a reduced depth in the central region compared to both ends with reference to the flow direction of the biological fluid sample, whereby the generation of dead zones, in which air bubbles may be present, may be further prevented. Thus, the depth L of the detection zone 5 in the central region is less than the depth H at both ends, for example the depth L may be approximately half the depth H. In the embodiment shown in fig. 5a, the detection zone 5 may have a projection 51 protruding from the bottom surface in a central region, the depth L of the detection zone 5 in the central region being <0.2 mm. In the embodiment shown in FIG. 5b, the detection zone 5 may have a projection 52 from the top surface in a central region, the depth L of the detection zone 5 in the central region being ≧ 0.2 mm. 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 increased, and thus 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 walls of the detection zone 5 in the inlet zone transition in a curved manner from both ends to the central zone, with reference to the flow direction of the fluid. The curve may be a spline curve, for example. 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 zones are 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 first increase incrementally and then increase decreasingly, in other words, the first derivative of the width may first increase and then decrease. The four sequentially occurring

fluid fronts

11, 12, 13, 14 are also depicted schematically in fig. 6, wherein the sequentially occurring fluid fronts are alternately depicted with solid lines and dashed lines. It follows that by the design of the shape of the side wall of the inlet area 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 at least a portion of the microfluidic flow channel upstream of the detection zone, for example, a majority of the section or the entire length, may be in the range of 1.5 to 3.5, for example, in the range of 2.0 to 3.0.

It is to be noted here that the height variations shown in fig. 4 are merely schematic. The expressions "rising in height" and "falling in height" as used in the present invention relate to one or more height-changing steps, i.e. there may be only one single level of height change between two zones, or there may also be multiple levels of height change, or there may also be a continuous height change. The transitions between the various height change steps depicted in fig. 3 are merely schematic. The transitions between the height change steps can be curved.

The microfluidic flow channel may have a hydrophilic surface. The sampling device may for example be constituted by a first and a second sheet laminated to each other, wherein the structure of the microfluidic flow channel may be made in at least one of the first and the second sheet. The second sheet material and the first sheet material are connected to one another in a material-locking manner, for example by gluing or welding. 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. The surface tension (viscous force, pressure) effect can be more pronounced at the microscale. The main dimensionless numbers affecting the movement of the fluid in the micro flow channel include reynolds number Re, weber number Wb, capillary number Ca, etc., and the main factors may include the wall wettability and the viscosity ratio between the liquids. The formula Ca ═ μ v/γ can be applied here, where μ is the measured viscosity of the fluid kg/(m · s), v is the average linear flow velocity of the fluid (m/s), and γ is the tension coefficient. When the Ca value is 10^-4～10^-1In between, capillary action may be evident.

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

The walls of the microchannel exhibit different wetting characteristics towards the liquid, mainly the influence of surface hydrophilicity/hydrophobicity on the slip. The surface hydrophilicity/hydrophobicity is related to the solid surface, i.e. to the strength of the interaction between the liquid and the solid molecules. For hydrophilic surfaces the contact angle theta is >90 deg., strong liquid-solid interactions will limit the liquid's glide, whereas for hydrophobic surfaces the contact angle theta <90 deg., is the opposite.

When the reagent reacts with the test fluid, the transport process is in a non-equilibrium state, and the process finally approaches the equilibrium. In the present system, the accompanying flow phenomena mainly include velocity and substance concentration, and thus the transport process mainly includes momentum transport and mass transport, which are caused by random movement of molecules. The location and manner of reagent entrapment is primarily adjusted based on the reagent's own molecular diffusion coefficient. The flux of diffusing species per unit time through a unit cross-sectional area perpendicular to the diffusion direction (referred to as diffusion flux, denoted by J) is proportional to the concentration gradient at that cross-section, i.e., the greater the concentration gradient, the greater the diffusion flux. The formula applies here:

where D is called the diffusion coefficient (m)²(s), C is the volume concentration (atomic number/m) of the diffusing substance (constituent element)³Or kg/m³)，

In the case of a concentration gradient, the "-" number 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 diffusion flux J is kg/(m)²·s)。

Flow at the microscale is typically characterized by a very low reynolds number Re of the flow, which is mostly in the laminar regime, where laminar, unmixed flow creates mixing difficulties. Here, through the microfluidic structure design, repeated segmentation, stretching, twisting or folding of the fluid can be realized by using a special channel geometric form under a low reynolds number, so that the contact probability between the original parallel flow layers is increased, and the effect of improving mixing is realized. In the curved flow passage, the flow velocities near the inner wall surface and near the outer wall surface are asymmetric due to the change of the curvature radius of the passage, so that the change of flow shear is caused, and the size of a flow vortex inside the fluid is changed. The sizes of the vortexes at the two sides of the inner wall and the outer wall of the continuous reducing curve can be changed alternately, so that the fluid at the upper half part and the lower half part can be exchanged and mixed. The Z-bend also reverses the direction of the swirl within the fluid, which better allows for thorough mixing of the components within the fluid.

In the process of movement of the microchannel network, a path with the minimum flow resistance is selected by the fluid, the flow resistance of the path where the fluid is located is increased by the fluid, the path selection of the subsequent fluid is influenced, and a nonlinear effect and side detection slippage are caused in the original linear low Reynolds number Stokes flow. Therefore, phenomena such as uneven flattening and air bubbles of the detection area are induced to influence the effectiveness and accuracy of detection. As the diameter (cross-section) of the conduit decreases, the flow resistance within the conduit increases dramatically. Therefore, different transition structures are needed to achieve the effect of uniform spreading 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 applications of the chemiluminescent type. The biological fluid sample to be detected can be added from the sample inlet 1, advances through self-driving force, reacts with the embedded reagent, is uniformly mixed through the mixing section, and then enters the detection zone for detection. Here, the microfluidic channel may be continuously hydrophilic. The embedded portion 2 may be formed, for example, by coating a dissolved reagent (chemical reagent, enzyme, antibody, nucleic acid, or the like) in the microfluidic flow channel and then drying it at the time of manufacturing the sampling device. Typically, dry chemical reagents (e.g., as indicators) used as validation reagents may be stored.

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

The embedded part 2 of the sampling device may contain detection reagents for enzymatic validation of leukocytes, nitrites, albumin, occult blood and creatinine. Under the condition that corresponding analytes exist in a liquid sample to be detected, the liquid sample to be detected with a determined amount is added into the sample inlet 1 by a pipette or a sample injection needle, the sample enters the sampling device and flows through the embedding part 2 to react with corresponding reagents, and then the sample continues to pass through the mixing section 3 under the action of capillary force, fluid surface tension and gravity to reach the detection zone 5. The detection region 5 can be transparent in its entirety, in which case the sample liquid can be analyzed visually and colorimetrically or by means of illumination techniques. And the content of the corresponding analyte in the sample liquid 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. Glucose is enzymatically oxidized by glucose oxidase to gluconic acid, with the release of hydrogen peroxide. Luminol (3-aminobenzene dihydrazide) is oxidized by an oxidizing agent such as hydrogen peroxide in an alkaline medium to emit light having a wavelength of about 425 nm. The reaction can be catalyzed by a number of metal ions. The chemiluminescence intensity is proportional to the concentration of hydrogen peroxide produced (i.e., to the glucose concentration) and can be measured by conventional light-sensitive sensors. The serum glucose content can be determined by measuring the luminescence intensity of the glucose standard solution and the plasma sample and comparing them.

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 can be pre-embedded in a first reagent embedding area and a biologic fluid sample consisting of luminol, potassium ferricyanide and alkaline solution of sodium hydroxide can be placed in a downstream second reagent embedding area. When detecting, can utilize the pipette to add a certain volume serum into introduction port 1, inside the sample gets into sampling device, the dry chemical reagent that contains in first reagent embedding district can take place to dissolve and react with the sample. Glucose in serum is oxidized into gluconic acid and hydrogen peroxide by glucose oxidase under the condition of neutral pH value, and then a sample enters a second reagent embedding area 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 according to the intensity of the generated optical signal.

Application example 3: determining the related test items (sandwich immunoassay) of the chorionic gonadotropin and other gonads in the serum. In this application the sampling device may work similarly.

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

Application example 4: adherent growth cell count and cell viability rate (e.g., HEK293 cells).

HEK293 cells were cultured in DMEM medium containing 10% fetal bovine serum in a carbon dioxide incubator with 5% CO₂And then, the mixture was subjected to static culture at 37 ℃. When the cells are grown to a certain stage, such as about 50% confluency, the cells are digested with trypsin and resuspended in DMEM medium. And uniformly mixing and adding the resuspended cells into a sample inlet of an instrument, automatically adding the sample into a sampling device for embedding AO (acridine orange) and PI (propidium iodide) dyes by the instrument through a liquid transfer system, and counting and evaluating the activity of the sample by using an instrument imaging system and software. Wherein the content of the first and second substances,AO can pass through the intact cell membrane, embedding the nuclei of all cells (both live and dead); PI can only pass through an incomplete cell membrane and intercalate into the nuclei of all dead cells. When observed using a fluorescence apparatus, AO-stained cells exhibited green fluorescence, and PI-stained cells exhibited red fluorescence. When the two dyes exist in cell nucleus, under proper ratio of AO and PI, the two dyes generate energy resonance transfer, so that living cells can excite green fluorescence under a blue channel, and dead cells can excite red fluorescence under the green channel. AO and PI stain HEK293 cells immediately and judge live, dead and total cells according to the staining. According to the AO and PI combined cell staining condition, the sampling device can accurately judge the cell concentration and the cell survival rate.

Application example 5: adherent growing cells are counted and cell viability (e.g. HEK293 cells) is measured using trypan blue as an embedding dye. In this application, the sampling device according to the invention can be operated similarly.

Trypan blue, a blue acid dye containing two azo chromophores, is a large, hydrophilic and tetrasulphonated anionic dye that can be universally used to detect the integrity of cell membranes and to assess cell viability. Live cells are not stained, while dead cells take up the dye, so non-stained live cells and blue-stained dead cells can be counted separately. Trypan blue can immediately stain HEK293 cells, analyze and identify total cells according to bright field imaging results, and judge live cells and dead cells according to staining conditions. The sampling device of the invention can accurately judge the cell concentration and the survival rate.

As other examples, the sampling device according to the present invention may also be applied in counting of suspension-grown cells and detection of cell viability, in cell transfection, in apoptosis detection, in detection and quantification of antigens, in detection and quantification of antibody affinity.

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 refer to like elements throughout.

Finally, it is pointed out that the above-described embodiments are only intended to be understood as an example of the invention and do not limit the scope of protection of the invention. It will be apparent to those skilled in the art that modifications may be made in the foregoing embodiments without departing from the scope of the invention.

Claims

1. A sampling device, characterized in that it comprises a microfluidic flow channel with a sample inlet (1) for inputting a biological fluid sample, an embedding part (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 zone (6) downstream of the detection zone and a gas 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, surface tension and capillary force of the fluid, wherein the trend of 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 output end of the mixing section from the sample inlet, and the fluid is decelerated again by the gravitational potential of the fluid before reaching the input end of the detection zone of the microfluidic channel.

2. A sampling device according to claim 1, characterized in that the microfluidic channel has a buffer section (4) arranged between the mixing section and the detection section for buffering the fluid before it enters the detection section.

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

preferably, the embedding comprises a concentrated embedding (2a) of reagents upstream of the mixing section and/or a dispersed embedding (2b) of reagents integrated in the mixing section.

4. A sampling device according to any one of claims 1 to 3 wherein the floor of the embedding portion and/or mixing section is lowered in height relative to the floor of the sample inlet; and/or

Preferably, the bottom surface of the embedding part and/or the mixing section remains constant in height in the flow direction of the fluid; and/or

Preferably, the bottom surface of the embedding part and/or the mixing section descends continuously at least locally in the flow direction of the fluid; and/or

Preferably, the depth of the embedding part and/or the mixing section is kept constant or increased relative to the depth of the section of the microfluidic channel between the sample inlet and the embedding part; and/or

Preferably, the top surface of the section of the microfluidic channel between the sample inlet to the output end of the mixing section remains constant in height; and/or

Preferably, the bottom surface of the input end of the detection zone rises in height relative to the bottom surface of the output end of the mixing section.

5. A sampling device according to any one of claims 2 to 4 wherein the floor of the buffer section is raised in height relative to the floor of the mixing section and the floor of the input end of the detection zone is raised in height relative to or at the same height as the floor of the output end of the buffer section; and/or

Preferably, the base of the buffer section rises at the input end of the buffer section in a step-like manner relative to the base of the output end of the mixing section; and/or

Preferably, the bottom surface of the buffer section rises continuously at least locally in the flow direction of the fluid; and/or

Preferably, the buffer section has a bend (41); and/or

Preferably, the microfluidic channel has a continuously descending bottom surface in a section from the sample inlet to the output end of the buffer section, and a discontinuously ascending bottom surface in the detection section; and/or

Preferably, the microfluidic channel has a constant depth in a section from the sample inlet to the output end 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; and/or

Preferably, the microfluidic channel has a flow path length of 100-160 mm in a section from the injection port to the output end of the buffer section, and a drop height of 2-3 mm between the injection port and the deepest point in a section from the injection port to the output end of the buffer section; and/or

Preferably, the buffer section is configured for restoring a laminar flow condition of the fluid in the buffer section; and/or

Preferably, a second microvalve for controlling the flow rate of the fluid is provided in the buffer section.

6. A sampling device according to any one of claims 1 to 5, characterized in that a first microvalve (8) for controlling the flow rate of the fluid is provided between the sample inlet and the embedding portion; and/or

The mixing section has at least one structure selected from the group consisting of: a bending section (31), a diameter-changing section (32), and a microcolumn;

preferably, the mixing section comprises a plurality of side-by-side subsections (30), each subsection having at least one structure selected from the group.

7. A sampling device according to any one of claims 1 to 6 wherein the detection zone is configured as a planar region, wherein the detection zone has an increased width dimension and a reduced depth in a central region compared to both ends with reference to the direction of flow of the fluid;

preferably, the detection zone has, in a central region, a projection (51) projecting from the bottom face and/or a projection (52) projecting from the top face;

preferably, with reference to the direction of flow of the fluid, the side wall of the detection zone in the inlet region transitions into a central region in the form of a curve, the shape of the curve being selected such that the fluid can flow in the detection zone substantially uniformly spread out;

preferably, in the entrance region of the detection zone, the width of the detection zone increases first incrementally and then incrementally.

8. A sampling device according to any one of claims 1 to 7 wherein the microfluidic flow channel has a cross-sectional width to depth ratio in a partial section or the full length of 1.5 to 3.5, preferably 2.0 to 3.0, upstream of the detection zone.

9. A sampling device according to any of claims 1 to 8 wherein the microfluidic channel has a hydrophilic surface.