TWI881473B - Nucleic acid detection device - Google Patents

Abstract

A nucleic acid detection device includes a tube holder, an illumination module, a detection module, and a driving module. The tube holder is used for accommodating a tube, which includes a reagent and a magnetizable element. The illumination module includes a light source, a magnet and a casing, and the light source and the magnet are installed on the casing. The driving module includes a motor, a lead screw and a slider. The lead screw is coupled to the motor and is driven to rotate by the motor. The slider is sleeved on the lead screw and moves in response to the rotation of the lead screw. The illumination module is coupled to and moved together with the slider, and has a reciprocating linear motion in a direction parallel to the lead screw. When the magnet is driven to deviate from the normal line of the tube, the magnetizable element maintains at a first position, and when the magnet is driven to align with the normal line of the tube, the magnetizable element is attracted by the magnet to move from the first position to a second position, thereby mixing the reagent in the tube.

Description

Nucleic acid detection device

This case is about a nucleic acid detection device, especially a nucleic acid detection device with magnetic mixing function.

The outbreak of COVID-19 in 2019 has made the field of molecular diagnosis a focus of global attention, prompting a rapid increase in the demand for in vitro diagnostics (IVD) test kits and testing equipment. In order to meet the rapidly growing demand for IVD testing and to achieve accurate and precise testing and analysis, how to preserve the test reagents (such as enzymes and antibodies) filled in the test kit is an important issue. If the test reagents become ineffective due to improper storage, it will result in false positive or false negative results.

In the past, if molecular detection reagents were stored and transported in wet form, they were usually supplemented with glycerol, mineral oil or other related additives to ensure the stability of the chemical structure of the reagent in wet form. In addition, wet molecular detection reagents must be stored in a low temperature environment (e.g., -20 degrees Celsius) and transported by cold chain transportation. However, the necessity of low temperature storage and cold chain transportation for wet reagents not only increases the cost of the test kit, but also causes inconvenience to users in storing the test kit. In addition, the refrigeration equipment, refrigerants and coolants required for cold chain storage and transportation also cause energy loss and environmental pollution.

The above inconvenience can now be solved by the mature freeze drying (freeze drying) technology. By placing the frozen molecular detection reagent in a vacuum environment for dehydration and drying, a stable solid form is formed, which improves the stability of the reagent and greatly extends the shelf life. In addition, the freeze-dried reagent greatly reduces the weight and volume, and no longer needs to be transported by cold chain to maintain the stability of the reagent, which reduces costs and reduces the impact on the environment. During the freeze-dried storage process of molecular detection reagents, freeze-drying preservatives (also known as excipients) are often used to prevent component denaturation. Freeze-dried preservatives can be divided into carbohydrates, polyols, polymers, surfactants, amino acids and salts according to their ingredients.

However, each lyophilized reagent and its lyophilized preservative have fixed and optimized components and ratios, that is, the added relevant lyophilized preservative has a certain volume concentration, which directly causes a certain degree of concentration gradient distribution problem after the lyophilized reagent is re-dissolved in water, buffer or reaction reagent. Therefore, it is necessary to give a period of time for the molecules in the solution to diffuse evenly, or an active perturbation method (such as using an oscillator or using a micropipette to pipette up and down) must be provided to evenly distribute the components of the reagent reaction. If the uneven concentration distribution of the freeze-dried reagent after rehydration is not resolved, it will easily reduce the reaction efficiency between the reagent and the reactant, and reduce the consistency of the reaction results, thereby affecting the interpretation of the test results.

Therefore, how to improve the above-mentioned lack of knowledge and skills is an issue that needs to be overcome urgently.

The purpose of this case is to provide a nucleic acid detection device, which mainly proposes an improved design for reagent mixing to solve the problem of uneven concentration distribution after freeze-dried reagents are reconstituted.

To achieve the above-mentioned purpose, the present invention provides a nucleic acid detection device, comprising: a plurality of tube placement slots for accommodating a plurality of tubes, wherein each tube includes a reagent and a magnetizable element; a light-emitting module, which is disposed on one side of the plurality of tube placement slots and includes a plurality of light sources, a magnet and a housing, wherein the plurality of light sources and the magnet are mounted on the housing; a detection module, which is disposed on the opposite side of the plurality of tube placement slots relative to the light-emitting module; and a driving module, which includes a motor, a lead screw and a slider, wherein the lead screw is coupled to the motor and is driven by the motor to rotate, and the slider is sleeved on the lead screw and performs reciprocating linear motion in response to the rotation of the lead screw. The light-emitting module is coupled to the slider and linked to the slider, so that the multiple light sources and magnets are synchronously driven by the motor to perform reciprocating linear motion in a direction parallel to the lead screw. When the magnet is driven to deviate from the normal level of the tube, the magnetizable element remains at the first position. When the magnet is driven to align with the normal level of the tube, the magnetizable element is attracted by the magnet and moves from the first position to the second position, thereby mixing the reagent in the tube.

In one embodiment, the first point is approximately at the bottom of the tube, and the second point is approximately near the magnet.

In one embodiment, the reagent is a lyophilized reagent.

In one embodiment, the magnetizable element is made of a metal material.

In one embodiment, the magnetizable element is spherical and has a diameter between 0.5 and 2 mm.

In one embodiment, the magnet is made of neodymium iron boron material.

In one embodiment, the maximum magnetic energy product of the magnet is between 45 and 55 MGOe, the cross-sectional area is between 1.5 and 3.5 mm, and the length is between 1 and 8 mm.

In one embodiment, the vertical distance between the magnet and the top of the housing is between 2.5 and 3.5 mm.

In one embodiment, the number of magnets is single.

In one embodiment, the mounting position of the magnet is misaligned with the mounting position of the light source.

In one embodiment, the drive module further includes a carrier, which is coupled and linked to the slider.

In one embodiment, the light-emitting module is carried on a carrier.

In one embodiment, the driving module further includes a photoelectric sensor, and the carrier includes an alignment fin having at least one slit thereon for determining whether the light source is aligned with the tube.

In one embodiment, the drive module further includes a linear slide rail, which is arranged parallel to the lead screw, and the carrier is slidably arranged on the linear slide rail.

In one embodiment, the slider includes a nut that is threaded onto the lead screw.

In one embodiment, the arrangement direction of the plurality of pipe placement grooves is parallel to the lead screw.

In one embodiment, the pipe further includes an annular wax layer disposed on the top of the reagent.

In one embodiment, the light-emitting module further includes a cover plate for accommodating a plurality of filters.

In one embodiment, the detection module includes a plurality of lens sets, a plurality of filters, and a plurality of light detectors.

In one embodiment, the nucleic acid detection device further includes a temperature control module, which includes a thermoelectric cooling chip.

1: Pipe fitting placement slot

11: Light entrance

12: Light exit

2: Light-emitting module

21: Light source

22: Filter

23: Magnet

24: Shell

241: Tank

242: Tank

243: Light exit

244: Open mouth

25: Cover plate

251: Tank

252: Light exit

253: Open mouth

3: Detection module

31: Lens set

32: Filter

33: Photodetector

34: Signal acquisition circuit board

4:Drive module

41: Motor

42: Lead screw

43: Slider

431: Nut

44: Carrier

441: First pair of fins

442: Narrow seam

443: Second fin

444: Narrow seam

45: Linear slide rail

461: First photo sensor

462: Two photoelectric sensors

5: Pipe fittings

51:Reagent

52: Magnetizable element

53: Annular wax layer

6: Temperature control module

61: Thermal conductive silicone sheet

62: Thermoelectric cooling chip

63: Heat sink

X, Y, Z: axis

A-A’, B-B’, C-C’, D-D’, E-E’: section lines

Figure 1 shows a schematic diagram of the nucleic acid detection device in this case.

Figure 2 shows a schematic diagram of the partial structure of the nucleic acid detection device in Figure 1.

Figure 3 shows the A-A’ cross-sectional structure diagram of Figure 2.

Figure 4A shows a schematic diagram of the light-emitting module of this case.

Figure 4B shows the B-B’ cross-sectional structure diagram of Figure 4A.

Figure 4C shows the exploded structure of Figure 4A.

Figure 5A shows a schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 5B shows the C-C’ cross-sectional structure diagram of Figure 5A.

Figure 5C shows the exploded structure of Figure 5A.

Figures 6 and 7 show schematic diagrams of the light-emitting module and the driving module of this case.

Figure 8 shows a schematic diagram of the carrier for this case.

Figures 9A and 9B show schematic diagrams of the magnet not being aligned with the pipe, where Figure 9B is a partial cross-sectional structure diagram of the D-D’ section of Figure 9A.

Figures 10A and 10B show schematic diagrams of the alignment of the magnet and the pipe, where Figure 10B is a partial cross-sectional structure diagram of E-E’ of Figure 10A.

Figures 11A to 11F show schematic diagrams of the alignment of magnets and pipes in sequence.

Figures 12A to 12F show schematic diagrams of the alignment of light sources and pipes in sequence.

Figures 13A to 13C show the effect of a magnetic mixing mechanism in promoting reagent mixing in a specific embodiment.

Figures 14A to 14C show the effect of the magnetic mixing mechanism in promoting reagent mixing in another specific embodiment.

Some embodiments that embody the features and advantages of this case will be described in detail in the following description. It should be understood that this case can have various changes in different forms, all of which do not deviate from the scope of this case, and the descriptions and drawings therein are essentially for illustrative purposes, not for limiting this case.

This case provides a nucleic acid detection device, which proposes an improved design for reagent mixing, and is used to solve the problem of uneven concentration distribution after the freeze-dried reagent is reconstituted, especially to solve the problem of fluorescence baseline drift and inconsistent detection results caused by uneven concentration distribution during the real-time polymerase chain reaction (qPCR) process. In view of the fact that the conventional magnetic mixing technology greatly increases the equipment volume and cost due to the mechanism setting, this case integrates the magnet into the light-emitting module required for nucleic acid detection, so that the magnet can be driven together with the light-emitting module to simplify the mechanism setting. Based on this concept, this case mainly uses the magnetic field contributed by a single magnet and moves along a single axis to drive the magnetizable element in the reaction tube to move, thereby providing a driving force for active perturbation of the reagent in the reaction tube, thereby achieving the purpose of uniform concentration distribution of the reagent in the reaction tube.

FIG. 1 shows a schematic diagram of the nucleic acid detection device of the present invention, FIG. 2 shows a schematic diagram of a local structure of the nucleic acid detection device of FIG. 1, and FIG. 3 shows an A-A' cross-sectional structure diagram of FIG. 2. As shown in FIG. 1 to FIG. 3, the nucleic acid detection device of the present invention mainly includes a plurality of tube placement slots 1, a light-emitting module 2, a detection module 3, and a drive module 4. The plurality of tube placement slots 1 are made of metal material and are arranged in a straight line along the X-axis to accommodate a plurality of tubes (such as PCR reaction tubes) 5, so the plurality of tubes 5 are also arranged in a straight line. The light-emitting module 2 and the detection module 3 are respectively arranged on two opposite sides of the plurality of tube placement slots 1, that is, they are respectively arranged on two opposite sides of the plurality of tubes 5. The light-emitting module 2 can provide light of a specific wavelength to excite the fluorescent substance in the tube 5, and then the detection module 3 receives the fluorescence emitted by the fluorescent substance to achieve the purpose of nucleic acid detection. The driving module 4 drives the movement of the light-emitting module 2 to align with the tube 5.

In one embodiment, the light emitting module 2 includes a plurality of light channels, the distance between two adjacent light channels is substantially equal to the distance between two adjacent tubes 5, and each light channel includes a light source 21 and a filter 22. The detection module 3 also includes a plurality of light channels, the distance between two adjacent light channels is substantially equal to the distance between two adjacent tubes 5, and each light channel includes a lens set 31, a filter 32, and a light detector 33, and the light detector 33 is further coupled to a signal acquisition circuit board 34. The light source 21 can be a light emitting diode, but is not limited thereto. The detection light source is provided by a light-emitting diode of a specific wavelength, and is incident on the tube 5 through the filter 22 and the light inlet 11 of the tube placement slot 1, thereby exciting the fluorescent substance in the tube 5; the fluorescence generated by the expansion reaction can be emitted through the light outlet 12 of the tube placement slot 1, and collected through the lens set 31, the filter 32, and the light detector 33, and sensed by the signal acquisition circuit board 34 at the back end and converted into a readable value.

In one embodiment, the nucleic acid detection device of the present case further includes a temperature control module 6, which is used to apply different temperatures for regulation, driving the nucleic acid molecules and the reaction reagents to continuously cycle in the steps of inactivation (denaturation), annealing (annealing) and extension (extension), so as to achieve the purpose of nucleic acid molecule expansion. As shown in Figure 3, the temperature control module 6 includes a heat-conducting silicone sheet 61, a thermoelectric cooling (TEC) chip 62, a heat sink 63 and a heat dissipation fan (not shown). In addition, the pipe placement slot 1 is made of metal material, such as copper with excellent thermal conductivity, so the pipe placement slot 1 is not only used to provide the pipe 5 for placement, but also used to conduct the heat energy generated by the thermoelectric cooling chip 62 to facilitate the PCR reaction.

FIG. 4A shows a schematic diagram of the light-emitting module of the present invention, FIG. 4B shows a B-B' cross-sectional structure diagram of FIG. 4A, and FIG. 4C shows an exploded structure diagram of FIG. 4A. As shown in FIG. 4A to FIG. 4C, in addition to the aforementioned light source 21 and filter 22, the light-emitting module 2 of the present invention further includes a magnet 23, a housing 24, and a cover plate 25. The housing 24 includes a slot 241 (shown in FIG. 3) that can accommodate a plurality of light sources 21, and a slot 242 that can accommodate the magnet 23, so that the light source 21 and the magnet 23 are both mounted and fixed on the housing 24, wherein the mounting position of the magnet 23 is misaligned with the mounting position of the light source 21, and is approximately located in the middle of two adjacent light sources 21 in the X-axis direction. The housing 24 further includes a plurality of light outlets 243 corresponding to the plurality of light sources 21, and an opening 244 corresponding to the magnet 23. The cover plate 25 includes a slot 251 (shown in FIG. 3 ) that can accommodate a plurality of filters 22, and a plurality of light outlets 252 corresponding to the plurality of filters 22, wherein the light outlets 243 of the housing 24 and the light outlets 252 of the cover plate 25 are aligned with each other in each light channel.

In the aforementioned embodiment, the magnet 23 is shielded by the cover 25. However, in another embodiment, the magnet 23 can also be exposed without being shielded by the cover 25. FIG. 5A shows a schematic diagram of the light-emitting module of another embodiment of the present case, FIG. 5B shows the C-C' cross-sectional structure diagram of FIG. 5A, and FIG. 5C shows the exploded structure diagram of FIG. 5A. As shown in FIG. 5A to FIG. 5C, the cover 25 further includes an opening 253 corresponding to the magnet 23, which is aligned with the opening 244 of the shell 24, so that the magnet 23 on the light-emitting module 2 is exposed without being shielded by the cover 25, and can be closer to the pipe 5 for magnetic mixing.

FIG6 and FIG7 show schematic diagrams of the light-emitting module and the driving module of the present invention, wherein the light-emitting module is driven by the driving module and is located at different positions. As shown in FIG6 and FIG7, the driving module 4 is a linear slide assembly, mainly including a motor 41, a lead screw 42 and a slider 43. The lead screw 42 is coupled to the motor 41 and is driven by the motor 41 to rotate. The slider 43 is sleeved on the lead screw 42 and performs reciprocating linear motion on the lead screw 42 in response to the rotation of the lead screw 42. The light-emitting module 2 is coupled to the slider 43 and linked to the slider 43, so that the light source 21 and the magnet 23 on the light-emitting module 2 are synchronously driven by the motor 41 and perform reciprocating linear motion in a direction parallel to the lead screw 42 (X-axis direction). In other words, the arrangement direction of the plurality of tube placement slots 1, the arrangement direction of the plurality of tubes 5, and the axial direction of the lead screw are all parallel to the X-axis direction, and the light source 21 and the magnet 23 on the light-emitting module 2 move in this single axis. Of course, the design of the drive module 4 driving the light-emitting module 2 can also be adjusted according to different needs and is not limited to the embodiment described in this case.

In one embodiment, the motor 41 is a stepper motor that can programmatically control the movement mode of the light-emitting module 2, but is not limited thereto.

In one embodiment, the slider 43 includes a nut 431, which is screwed on the lead screw 42, thereby driving the slider 43 to perform reciprocating linear motion on the lead screw 42.

In one embodiment, the driving module 4 further includes a carrier 44 and a linear slide 45, and the linear slide 45 is arranged parallel to the lead screw 42. The carrier 44 is coupled and linked to the slider 43, and can be slidably arranged on the linear slide 45. The light-emitting module 2 is carried on the carrier 44, so it can be coupled and linked to the slider 43, so that the light source 21 and the magnet 23 on the light-emitting module 2 are synchronously driven by the motor 41 and reciprocate linearly in a direction parallel to the lead screw 42 (X-axis direction).

In one embodiment, the driving module 4 further includes a design of an alignment structure for determining whether the light source 21 is aligned with the tube 5. Please refer to Figures 6 to 8, wherein Figure 8 shows a schematic diagram of the carrier of the present invention. As shown in Figures 6 to 8, the driving module 4 includes a first photoelectric sensor 461, which is a photointerrupter having a light-emitting element and a light-receiving element arranged opposite to each other. When the light-shielding portion or the light-transmitting portion of an object passes through, a current change will be generated depending on whether the light path of the photointerrupter is blocked or not. The carrier 44 includes a first alignment fin 441, on which a plurality of slits 442 are provided, and the distance between two adjacent slits 442 is approximately equal to the distance between two adjacent tubes 5. When the slit 442 passes through the first photo sensor 461, the first photo sensor 461 detects that the light path is not blocked, indicating that at least one light source 21 is aligned with the tube 5, and the magnet 23 is not aligned with the tube 5, and the light source 21 switch can be turned on to emit the detection light source. Through the design of the alignment structure, the magneto-hybridization and optical detection paths can be separated to avoid shielding the detection light source path due to magneto-hybridization during the optical detection period, affecting the acquisition of the detection data.

In one embodiment, the drive module 4 further includes a second photo sensor 462, and the carrier 44 includes a second alignment fin 443, on which a slit 444 is provided. The slit 444 is provided for zero point positioning. When the slit 444 passes through the second photo sensor 462, the second photo sensor 462 detects that the light path is not blocked, indicating that the carrier 44 has returned to the origin of the reciprocating linear motion (as shown in FIG. 6).

The following will further illustrate the magneto-hybrid mechanism of this case with reference to Figures 9A, 9B, 10A and 10B, wherein Figures 9A and 9B are schematic diagrams showing that the magnet is not aligned with the pipe, and Figure 9B is a partial cross-sectional structure diagram of D-D’ of Figure 9A, while Figures 10A and 10B are schematic diagrams showing that the magnet is aligned with the pipe, and Figure 10B is a partial cross-sectional structure diagram of E-E’ of Figure 10A.

First, it is explained that the tube 5 is made of polymer material and is a cone-shaped container that opens upward and is wide at the top and narrow at the bottom. The tube placement groove 1 is also a structure that opens upward and is wide at the top and narrow at the bottom. Its inner diameter is designed to conform to and fit closely to the tube 5. The tube 5 mainly contains a reagent 51 and a magnetizable element 52. The reagent 51 includes but is not limited to a PCR reaction reagent, especially a freeze-dried PCR reaction reagent. The reagent includes nucleotides, primers, probes, enzymes, sugars, stabilizers, etc. The tube 5 further includes an annular wax layer 53 on the top of the reagent 51. This annular structure allows the test solution, such as nucleic acid extract, to be added from the center, and then melted by the temperature control module 6, and covered on the surface of the reaction solution to form an isolation layer to prevent the evaporation of the reaction solution during the temperature control cycle and prevent the expansion product from escaping into the environment and causing pollution.

In one embodiment, the magnetizable element 52 is made of metal material, and its surface is usually coated with a layer of corrosion-resistant material (such as nickel, chromium, molybdenum or polymer material) to avoid oxidation reaction with the reagent 51. The magnetizable element 52 will naturally settle to the bottom of the pipe 5 due to gravity. The shape of the magnetizable element 52 can be, but not limited to, spherical, square, and cylindrical, among which the spherical shape is preferred because it can conform to and fit closely to the bottom of the pipe 5, reducing the generation of bubbles, and the diameter of the sphere is between 0.5 and 2 mm, for example, 0.5, 0.58, 0.8 or 2 mm. For example, the magnetizable element 52 can be a steel ball.

When the light-emitting module 2 embedded with the magnet 23 is driven by the driving module 4 so that the center of the magnet 23 deviates from the normal level of the tube 5 (i.e., it is not aligned with the tube 5), the magnetizable element 52 placed in the tube 5 is not actuated by the magnetic field and naturally maintains at the first position due to its own mass, that is, roughly at the bottom of the tube 5 (as shown in Figures 9A and 9B). When the light-emitting module 2 embedded with the magnet 23 is driven by the driving module 4 so that the center of the magnet 23 is aligned with the normal level of the individual pipe 5 (i.e. aligned with the pipe 5), the magnetic field contributed by the magnet 23 will drive the magnetizable element 52 in the pipe 5 to move from the first position to the second position, i.e. move upward from the bottom of the pipe 5 to a position close to the magnet 23 (as shown in Figures 10A and 10B). When the driving module 4 drives the magnet 23 to move to the next pipe 5, the center of the magnet 23 deviates from the normal level of the original pipe 5, and the magnetizable element 52 that was originally attracted by the magnet and moved to the second position will naturally settle back to the first position due to its own mass because it is no longer attracted by the magnet. Therefore, by programmable repeated movement and alignment, the magnetizable element 52 in the tube 5 is driven to move, thereby providing a driving force for active disturbance of the reagent 51 in the tube 5, so as to achieve the purpose of uniform concentration distribution of the reagent 51 in the tube 5.

The above-mentioned embodiment is illustrated by using a single magnet 23 embedded in the light-emitting module 2 as an example, but it is not limited to this. The magnetic mixing of the reagent 51 in the tube 5 can be adjusted by programming the stop time and the number of cyclic movements of the magnet 23 along the multiple tubes 5. For example, the stop time can be set to 0 seconds, 200 milliseconds, 300 milliseconds, 400 milliseconds, 500 milliseconds, 600 milliseconds, 700 milliseconds, 800 milliseconds, 900 milliseconds or 1 second, and the number of cyclic movements can be set to 10 times, 20 times or 30 times. These parameters can be adjusted according to different needs and are not limited to those described in the embodiment of this case.

According to the design of the nucleic acid detection device of the present case, after the tube 5 injected with the solution to be tested is placed in the tube placement slot 1, the light-emitting module 2 can be driven by the driving module 4 in a programmable manner, and the alignment structure design can be used to determine whether the light source 21 is aligned with the tube 5 to control the switch of the light source 21, so as to avoid the magnetizable element 52 being magnetically attracted to the tube 5 and moving during the optical detection period to block the detection light source path and affect the detection data acquisition. For example, the nucleic acid detection device first performs a magneto-mixing operation, as shown in Figures 11A to 11F, the magnet 23 is driven to be positioned in each tube 5 in sequence to mix the reagents, and can be moved in a circular manner to mix them fully. Then, the temperature control module 6 is cooperated to expand the nucleic acid molecules in the tube 5. When the expansion is completed, the drive module 4 drives the alignment of the light source 21 and the pipe 5. The light source 21 is turned on in the alignment state for optical detection. As shown in Figures 12A to 12F, the light source 21 is driven to align with the pipe 5 in sequence. During the optical detection operation, the light source 21 is aligned with the normal level of the pipe 5, and during the magneto-hybrid operation, the center of the magnet 23 is aligned with the normal level of each pipe 5. In this way, the light source 21 and the magnet 23 can be set on the same mechanism component and their functions do not interfere with each other, greatly reducing the complexity of the mechanism.

In one embodiment, the magnet 23 is made of neodymium iron boron material, the maximum magnetic energy product ((BH)max) is between 45 and 55 MGOe, the cross-sectional area of the magnet 23 is between 1.5 and 3.5 mm, the length of the magnet 23 is between 1 and 8 mm, and the vertical distance between the magnet 23 and the top of the housing 24 is between 2.5 and 3.5 mm.

In one embodiment, the number of magnets 23 is single and is embedded in the center of the housing 24. Since the magnets 23 are driven by the driving module 4 to move and are positioned individually for each tube 5, only a single magnet 23 is needed to achieve magnetic mixing of all tubes 5. Of course, the number of magnets 23 is not limited to a single one, but can be more than two, thereby shortening the moving distance of the light-emitting module 2.

The following is a specific example to illustrate the magnetic mixing effect of the nucleic acid detection device of the present case. In this specific example, the nucleic acid detection device is provided with a single magnet 23, which is made of neodymium iron boron material, has a maximum magnetic energy product ((BH)max) of 50~53MGOe, a cross-sectional area of 2mm and a length of 6mm. The magnet 23 is located in the center of the shell 24 and the vertical distance from the top of the shell 24 is 2.5mm, so that when the magnetizable element 52 actuated by the magnetic field moves to the second position, it is just close to and located at the bottom of the wax isolation layer. The magnetizable element 52 accommodated in the pipe 5 is spherical in shape, with a diameter of 0.58mm, and its material is 440 series stainless steel. When the magnet 23 is driven to move cyclically along a plurality of pipes 5, the waiting time of each pipe 5 is set to 200 milliseconds, and the number of mixed cycles is set to 10 times, 20 times and 30 times.

In this specific embodiment, the reagent used for detection is 25μL SARS-CoV-2 lyophilized-cake, and the nucleic acid detection device of this case is used with the nucleic acid extraction cartridge to extract the SARS-CoV-2 standard and perform the full process test of RT-PCR, and the detection targets are the RdRp and N genes of the virus. Using viral transport medium (VTM) as the matrix, 750cp/mL SARS-CoV-2 standard and 3 x 10^4 human cells are prepared, and 0.4mL is taken as a sample. When the extraction is completed, the magnetic mixing mechanism is set to: no mixing, mixing 10 times, mixing 20 times and mixing 30 times, and subsequent nucleic acid amplification and optical detection are performed. Figures 13A to 13C show the effect of the magneto-mixing mechanism in this specific embodiment on promoting reagent mixing, wherein Figure 13A shows the RT-PCR fluorescence curve signal of the RdRp gene, Figure 13B shows the RT-PCR fluorescence curve signal of the N gene, and Figure 13C shows the Cq value and the expanded fluorescence value (△RFU). As shown in the figure, as the number of mixing increases, the fluorescence signal gradually increases and forms a typical S-shaped expansion curve. The Cq value and the expanded fluorescence value (△RFU) are calculated by the regression model, and the result is shown in Figure 13C. The magneto-mixing mechanism of the nucleic acid detection device in this case does help improve the reaction performance.

To verify the feasibility again, in another specific embodiment, a magnetomixing test was performed with 10 μL of SARS-CoV-2 lyophilized-cake, wherein the sample included 1,000 cp/mL SARS-CoV-2 standard and 3 x 10^4 human cells, and 0.4 mL of the sample was taken for full-process detection. Figures 14A to 14C show the effect of the magnetomixing mechanism in promoting reagent mixing in this specific embodiment, wherein Figure 14A shows the RT-PCR fluorescence curve signal of the RdRp gene, Figure 14B shows the RT-PCR fluorescence curve signal of the N gene, and Figure 14C shows the Cq value and the expanded fluorescence value (△RFU). As shown in the figure, when there is no mixing action for 10μL of drying reagent, the RT-PCR fluorescence curve is flat and has no amplification, and neither the RdRp gene nor the N gene can be detected. As the number of mixing times increases to 10 and 20 times, the fluorescence signal is significantly enhanced.

The above verification results also show that when the volume of the dried reagent is reduced, the shape is more dense, and the concentration gradient may become larger after re-dissolving, making it more difficult to homogenize. If combined with the magnetic mixing mechanism of this case, it can effectively accelerate the mixing of the reagent to meet the subsequent PCR results. In other words, the magnetic mixing mechanism of this case has the effect of promoting the mixing of PCR solutions.

In summary, the present invention provides a nucleic acid detection device, including a plurality of tube placement slots, a light-emitting module, a detection module, and a driving module, and further integrates a magnet into the light-emitting module so that the magnet and the light-emitting module can be driven together to simplify the mechanism setting. That is, in addition to providing the excitation light source required for PCR fluorescent detection, the light-emitting module is also embedded with a magnet to perform magnetic mixing on the reagent in the tube. With the action of the drive module, the magnet moves in a single axis parallel to the arrangement direction of the pipes, and through programmable repeated movement and alignment, the magnetizable element in the pipe is driven to move, thereby providing a driving force for active disturbance of the reagent in the pipe, promoting uniform distribution of the reagent concentration in the pipe, thereby improving the reaction efficiency and consistency of the reaction results, and avoiding a significant increase in equipment volume and cost.

Although the present invention has been described in detail by the above embodiments and can be modified in various ways by those familiar with the art, they are still within the scope of the patent application.

1: Pipe fitting placement slot

2: Light-emitting module

3: Detection module

4:Drive module

5: Pipe fittings

X, Y, Z: axis

A-A’: section line

Claims (20)

A nucleic acid detection device comprises: A plurality of tube placement slots for accommodating a plurality of tubes, wherein each of the tubes comprises a reagent and a magnetizable element; A light-emitting module, disposed on one side of the plurality of tube placement slots, and comprising a plurality of light sources, a magnet and a housing, wherein the plurality of light sources and the magnet are mounted on the housing; A detection module, disposed on the opposite side of the plurality of tube placement slots relative to the light-emitting module; and A driving module, comprising a motor, a lead screw and a slider, wherein the lead screw is coupled to the motor and driven by the motor to rotate, and the slider is sleeved on the lead screw and performs reciprocating linear motion in response to the rotation of the lead screw, The light-emitting module is coupled to the slider and linked to the slider, so that the plurality of light sources and the magnet are synchronously driven by the motor to perform reciprocating linear motion in a direction parallel to the lead screw. When the magnet is driven to deviate from a normal level of the tube, the magnetizable element is maintained at a first position. When the magnet is driven to align with the normal level of the tube, the magnetizable element is moved from the first position to a second position by the magnetic attraction of the magnet, thereby mixing the reagent in the tube. A nucleic acid detection device as described in claim 1, wherein the first point is approximately located at the bottom of the tube, and the second point is approximately located near the magnet. A nucleic acid detection device as described in claim 1, wherein the reagent is a freeze-dried reagent. A nucleic acid detection device as described in claim 1, wherein the magnetizable element is made of a metal material. A nucleic acid detection device as described in claim 1, wherein the magnetizable element is spherical and has a diameter between 0.5 and 2 mm. A nucleic acid detection device as described in claim 1, wherein the magnet is made of a neodymium iron boron material. A nucleic acid detection device as described in claim 1, wherein the maximum magnetic energy product of the magnet is between 45 and 55 MGOe, the cross-sectional area is between 1.5 and 3.5 mm, and the length is between 1 and 8 mm. A nucleic acid detection device as described in claim 1, wherein the vertical distance between the magnet and the top of the housing is between 2.5 and 3.5 mm. A nucleic acid detection device as described in claim 1, wherein the number of the magnet is single. A nucleic acid detection device as described in claim 1, wherein the mounting position of the magnet and the mounting position of the light source are misaligned. A nucleic acid detection device as described in claim 1, wherein the driving module further includes a carrier that is coupled and linked to the slider. A nucleic acid detection device as described in claim 11, wherein the light-emitting module is carried on the carrier. The nucleic acid detection device as described in claim 11, wherein the driving module further includes a photosensor, and the carrier includes an alignment fin having at least one slit thereon for determining whether the light source is aligned with the tube. The nucleic acid detection device as described in claim 11, wherein the driving module further includes a linear slide rail, which is arranged parallel to the lead screw, and the carrier is slidably arranged on the linear slide rail. A nucleic acid detection device as described in claim 1, wherein the slider includes a nut which is threaded onto the guide screw. A nucleic acid detection device as described in claim 1, wherein the arrangement direction of the plurality of tube placement grooves is parallel to the lead screw. A nucleic acid detection device as described in claim 1, wherein the tube further includes an annular wax layer disposed on the top of the reagent. A nucleic acid detection device as described in claim 1, wherein the light-emitting module further includes a cover plate for accommodating a plurality of filters. A nucleic acid detection device as described in claim 1, wherein the detection module includes a plurality of lens sets, a plurality of filters, and a plurality of photodetectors. The nucleic acid detection device as described in claim 1 further includes a temperature control module, which includes a thermoelectric cooling chip.

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