Efficient DNA enrichment device for on-site investigation

Abstract

The utility model discloses a high-efficiency DNA (deoxyribonucleic acid) enrichment device for on-site investigation. The enrichment device comprises a connecting part, a communicating pipe, a suction head, a swab, a limiting part and a sealing cover, the limiting part, the connecting part, the communicating pipe and the swab are sequentially connected, the suction head is connected to the connecting part, an extrusion cavity is formed in the suction head, the limiting part is located in the extrusion cavity, the limiting part can be broken to enable the extrusion cavity to communicate with the communicating pipe, and the sealing cover is arranged on the peripheries of the communicating pipe and the swab in a sleeving mode and connected to the connecting part. The enrichment device is provided with the limiting part and the extrusion cavity, when the enrichment device needs to be used, the limiting part can be broken off, and at the moment, a biological material evidence collection reagent in the extrusion cavity can be released into the swab through the communicating pipe by extruding the suction head; after wiping, a biological material evidence collection reagent can be recycled into the extrusion cavity under the action of negative pressure generated by extruding the suction head, so that all cast-off cells and DNA on the surface of a material evidence can be sufficiently and effectively eluted and adsorbed, the detection rate of DNA is favorably improved, and cross contamination is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of DNA collection and detection, and in particular to a high-efficiency DNA enricher used for on-site investigation. Background Art

[0002] In the field of criminal evidence investigation, the discovery and extraction of criminal evidence such as fingerprint evidence, palm print evidence, and trace evidence that can reflect DNA characteristics left by suspects at the scene is the key to building a chain of evidence of criminal facts and laying the legal evidence basis for punishing crimes. At present, in the extraction of DNA evidence, there are many ways to transfer and extract trace DNA retained on different carriers, such as wiping, sticking, shearing, negative pressure adsorption, and oscillation washing. However, in recent years, due to the influence of environmental factors such as the diversification of crime scenes, the sophistication of criminals, and unsatisfactory investigation conditions, as well as the influence of various objective factors of the evidence itself, such as the large workload of blind extraction, dents on the surface of evidence, the degradation of DNA retained by the object, and the poor preservation of cotton swabs after collection, it is difficult to obtain satisfactory DNA test results by only using conventional transfer extraction methods such as wiping, sticking, shearing or scraping, which greatly affects the detection rate of DNA. During the on-site investigation, it is difficult to extract all the DNA through the conventional dry-wet two-step method for some evidence materials with strong permeability or special shapes such as grooves or gaps, which is prone to DNA leakage and thus cannot obtain satisfactory DNA test analysis results. The dry-wet two-step wiping extraction is to first wipe the surface of the object with a wet ordinary cotton swab, and then wipe it with a dry cotton swab for transfer. In the above collection process, the operator needs to carry a tube of distilled water and two cotton swabs, and the cotton swabs need to be stored in a specific container. The cotton swabs and distilled water are carried separately, and the entire operation process is cumbersome, and only a little distilled water is needed to soak the cotton swabs. Carrying a tube of distilled water, if the operation is not careful, will cause the distilled water to be contaminated, which is very easy to cause waste. At the same time, if the amount of water is too little, it is difficult to collect all the biological evidence in the suspected part of the sample; and too much water will accelerate the degradation rate of cellular DNA in the biological evidence, increase the difficulty of DNA extraction in the later stage, and even cause the situation that DNA cannot be detected.

[0003] Therefore, it is very necessary to provide an efficient DNA enricher for field investigation that can be applied to the dry and wet two-step wiping method and can achieve high-quality extraction. Utility Model Content

[0004] In order to overcome the shortcomings of the prior art, the purpose of the utility model is to provide an efficient DNA enricher for on-site investigation, which can fully and effectively elute and adsorb all detached cells and DNA on the surface of physical evidence, which is beneficial to improve the detection rate of DNA and will not cause cross contamination.

[0005] In order to solve the above problems, the technical solutions adopted by the utility model are as follows:

[0006] A high-efficiency DNA enricher for on-site investigation, comprising a connecting part, a connecting tube, a suction head, a swab, a limiting part and a sealing cover; the first end of the connecting tube is connected to the first end of the connecting part, and a first flow channel is provided in the connecting tube; the first end of the suction head is connected to the second end of the connecting part, and an extrusion cavity is provided inside the suction head, and the extrusion cavity is filled with a biological evidence collection reagent; the swab is connected to the second end of the connecting tube and is in communication with the first flow channel; the limiting part is located in the extrusion cavity, and the first end of the limiting part is connected to the second end of the connecting part, and the limiting part The connection between the extrusion chamber and the first flow channel can be blocked, and the limiting portion can be broken, so that the extrusion chamber and the first flow channel can be connected to each other after the limiting portion is broken; the sealing cover is sleeved on the outer periphery of the connecting tube and the swab, and the first end of the sealing cover is detachably connected to the first end of the connecting portion; wherein, after the limiting portion is broken, the biological evidence collection reagent in the extrusion chamber can be released into the swab by squeezing the suction head, and the biological evidence collection reagent can be recovered into the extrusion chamber through the swab under the action of the negative pressure generated by squeezing the suction head.

[0007] As a preferred embodiment of the utility model, a second flow channel is opened inside the limiting portion, a first end of the second flow channel is connected to the first flow channel, a second end of the second flow channel can be closed by the second end of the limiting portion, and after the limiting portion is broken, the second end of the second flow channel is connected to the extrusion chamber.

[0008] As a preferred embodiment of the present invention, a third flow channel is opened inside the connecting portion, and two ends of the third flow channel are respectively connected to the first flow channel and the second flow channel.

[0009] As a preferred embodiment of the present invention, the surface of the suction head is marked with scale lines.

[0010] As a preferred embodiment of the present utility model, the suction head is made of soft material.

[0011] As a preferred embodiment of the present invention, the sealing cover is made of a hard material.

[0012] As a preferred embodiment of the present invention, the first end of the sealing cover is threadedly connected to the first end of the connecting portion.

[0013] As a preferred embodiment of the present invention, an annular indentation is provided on the outer periphery of the limiting portion.

[0014] As a preferred embodiment of the present invention, the first end of the suction head has a sleeve portion, and the sleeve portion is sleeved on the outer periphery of the first end of the connecting portion.

[0015] As a preferred embodiment of the present invention, a sealing ring is provided between the sleeve portion and the connecting portion, and inner and outer sides of the sealing ring abut against the connecting portion and the sleeve portion respectively.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The efficient DNA enricher described in the utility model is provided with a suction head and filled with a biological evidence collection reagent with a certain viscosity. When not in use, the limiting part can block the communication between the extrusion chamber and the first flow channel, which can prevent the biological evidence collection reagent in the extrusion chamber from entering the first flow channel and being lost through the swab. When it is needed, the limiting part can be broken off so that the extrusion chamber and the first flow channel are interconnected. At this time, the suction head can be squeezed to release the biological evidence collection reagent in the extrusion chamber through the first flow channel into the swab. A swab carrying the biological evidence collection reagent is used to wipe the surface of the evidence. After wiping, the suction head is released, and the negative pressure generated by squeezing the suction head can be used to suck the biological evidence collection reagent containing exfoliated cells and DNA back into the suction head. The invention not only can well avoid the cross contamination caused by repeated use of the same reagent in the prior art, but also can be easy to operate and use. After the biological evidence collection reagent is sucked back, the residual biological evidence collection reagent is wiped with a dry cotton swab, which can fully and effectively elute and adsorb all the exfoliated cells and DNA on the surface of the evidence, thereby increasing the amount of DNA extraction, thereby achieving high-quality collection of biological evidence on the scene, which is beneficial to improving the DNA detection rate, and makes up for the deficiency of the conventional wiping extraction method using ordinary cotton swabs for some special evidence, thereby achieving the purpose of high-quality collection of biological evidence on the scene. The collector can be widely used in most crime scenes and DNA laboratories in China. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of a high-efficiency DNA enricher according to an embodiment of the utility model;

[0019] Figure 2 A cross-sectional view of a high-efficiency DNA enricher according to an embodiment of the utility model;

[0020] Figure 3 This is an exploded view of a high-efficiency DNA enricher according to an embodiment of the present utility model.

[0021] Description of the accompanying drawings: 100 connecting part, 110 third flow channel, 200 connecting tube, 210 first flow channel, 300 suction head, 310 extrusion chamber, 320 sleeve part, 400 swab, 500 restriction part, 510 second flow channel, 520 annular indentation, 600 sealing cover, 700 sealing ring. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] Reference Figures 1 to 3 The embodiment of the utility model provides a high-efficiency DNA enricher, including a connecting portion 100, a connecting tube 200, a pipette tip 300, a swab 400, a limiting portion 500 and a sealing cover 600, as shown in FIG. Figure 2 As shown, the limiting portion 500, the connecting portion 100, the connecting tube 200 and the swab 400 are connected in sequence.

[0024] Reference Figure 2 and Figure 3 The first end of the connecting tube 200 is connected to the first end of the connecting portion 100. The connecting tube 200 can be integrally formed with the connecting portion 100 or can be separately formed. For example, the first end of the connecting tube 200 can be detachably plugged into the first end of the connecting portion 100. Figure 2 A first flow channel 210 is opened in the connecting pipe 200 .

[0025] Reference Figures 1 to 3 , the first end of the suction tip 300 is connected to the second end of the connecting portion 100, and an extrusion cavity 310 is provided inside the suction tip 300, and the extrusion cavity 310 is filled with a biological evidence collection reagent. The portion of the suction tip 300 used for extrusion deformation is made of a flexible and elastic material, such as silicone, so that the suction tip 300 is easily deformed when squeezed, and the extrusion cavity 310 inside it can be deformed, so that the biological evidence collection reagent in the extrusion cavity 310 can be released. After the suction tip 300 is released, the suction tip 300 can be deformed outward and restored, and the negative pressure generated by squeezing the suction tip 300 is used to suck the biological evidence collection reagent back into the extrusion cavity 310 of the suction tip 300. Furthermore, the first end of the suction head 300 can be sleeved on the outer periphery of the second end of the connecting part 100, and the portion of the suction head 300 used for sleeve connection with the connecting part 100 can be made of materials such as PP or PE, and the connection between the suction head 300 and the connecting part 100 can be fixed and sealed by glue after sleeve connection, or fixed and sealed by sleeve connection with a sealing ring and then threaded connection. Figure 3As shown, the first end of the suction head 300 is provided with a sleeve portion 320, which is sleeved on the outer periphery of the first end of the connecting portion 100, and a sealing ring 700 is provided between the sleeve portion 320 and the connecting portion 100, and the inner and outer sides of the sealing ring 700 respectively abut the connecting portion 100 and the sleeve portion 320.

[0026] Reference Figure 2 and Figure 3 The swab 400 is connected to the second end of the connecting tube 200 and is connected to the first flow channel 210, that is, at least a part of the structure of the swab 400 is exposed at the outlet of the first flow channel 210 to absorb and release the biological evidence collection reagent. The swab 400 is a cotton swab head containing cotton or wrapped with a flocked swab, which can increase the friction of wiping, so that the exfoliated cells or DNA on the evidence carrier are more likely to fall off into the biological evidence reagent, which is convenient for recovery and preservation.

[0027] Continue to refer to Figure 2 and Figure 3 , the limiting part 500 is located in the extrusion chamber 310, and the first end of the limiting part 500 is connected to the second end of the connecting part 100. During packaging, transportation and storage, the limiting part 500, as a stopper, can block the communication between the extrusion chamber 310 and the first flow channel 210, and can prevent the biological evidence collection reagent in the extrusion chamber 310 from entering the first flow channel 210 and flowing through the swab 400. The limiting part 500 is made of an easily broken material, and the limiting part 500 can be broken when an external force is applied. After the limiting part 500 is broken, the extrusion chamber 310 and the first flow channel 210 can be connected to each other. When the suction head 300 is squeezed, the biological evidence collection reagent in the extrusion chamber 310 can flow into the first flow channel 210 and then be released into the swab 400. After the suction head 300 is released, the biological evidence collection reagent can be recovered into the extrusion chamber 310 through the swab 400 and the first flow channel 210 under the negative pressure generated by squeezing the suction head 300. Further, refer to Figure 2 An annular notch 520 may be prefabricated on the outer periphery of the limiting portion 500 so that the limiting portion 500 can be broken along the annular notch 520 when force is applied.

[0028] Reference Figures 1 to 3, the sealing cover 600 is sleeved on the outer circumference of the connecting tube 200 and the swab 400, and the first end of the sealing cover 600 is detachably connected to the first end of the connecting part 100. During packaging, transportation and storage, the sealing cover 600 can protect the connecting tube 200 and the swab 400, prevent the swab 400 from being contaminated by the outside world, and prevent the connecting tube 200 from being broken by external forces. When in use, the sealing cover 600 can be removed to expose the swab 400, and then the limiting part 500 is broken and the suction head 300 is squeezed, and the swab 400 is used to wipe the surface of the evidence. After wiping, the sealing cover 600 can be covered again to prevent contamination. Furthermore, the sealing cover 600 can be made of a hard material, and the connection between the sealing cover 600 and the connecting part 100 can be a threaded connection. Specifically, an internal thread can be opened at the first end of the sealing cover 600, and an external thread can be opened at the first end of the connecting part 100, so as to realize the threaded connection between the sealing cover 600 and the connecting part 100, so as to facilitate the installation and disassembly of the sealing cover 600.

[0029] The efficient DNA enricher described in the utility model is provided with a suction head 300 and filled with a biological evidence collection reagent with a certain viscosity in the suction head 300. When not in use, the limiting part 500 can block the communication between the extrusion chamber 310 and the first flow channel 210, which can prevent the biological evidence collection reagent in the extrusion chamber 310 from entering the first flow channel 210 and flowing through the swab 400. When it is needed, the limiting part 500 can be broken to make the extrusion chamber 310 and the first flow channel 210 communicate with each other. At this time, the suction head 300 can be squeezed to release the biological evidence collection reagent in the extrusion chamber 310 through the first flow channel 210 into the swab 400. The swab 400 carrying the biological evidence collection reagent is used to wipe the surface of the evidence. After wiping, the suction head 300 is released, that is, the negative pressure generated by squeezing the suction head 300 can be used to suck the biological evidence collection reagent containing the exfoliated cells and DNA back into the suction head 300. The invention not only can well avoid the cross contamination caused by repeated use of the same reagent in the prior art, but also can be easy to operate and use. After the biological evidence collection reagent is sucked back, the residual biological evidence collection reagent is wiped with a dry cotton swab, which can fully and effectively elute and adsorb all the exfoliated cells and DNA on the surface of the evidence, thereby increasing the amount of DNA extraction, thereby achieving high-quality collection of biological evidence on the scene, which is beneficial to improving the DNA detection rate, and makes up for the deficiency of the conventional wiping extraction method using ordinary cotton swabs for some special evidence, thereby achieving the purpose of high-quality collection of biological evidence on the scene. The collector can be widely used in most crime scenes and DNA laboratories in China.

[0030] In some embodiments, the connecting tube 200 can be integrally formed with the limiting portion 500, that is, the limiting portion 500 is integrally formed at the first end of the connecting tube 200. During installation, the limiting portion 500 at the first end of the connecting tube 200 can be inserted along the first end of the connecting portion 100 until the limiting portion 500 extends from the second end of the connecting portion 100 into the extrusion cavity 310. When the limiting portion 500 is broken, the first flow channel 210 in the connecting tube 200 can be interconnected with the extrusion cavity 310. In other embodiments, the connecting tube 200 and the limiting portion 500 are separately provided, and the two are respectively connected to the first end and the second end of the connecting portion 100. Both can be integrally formed with the connecting portion 100 or separately provided. For example Figure 2 As shown, the connecting tube 200 is connected to the first end of the connecting part 100, the limiting part 500 is connected to the second end of the connecting part 100, a second flow channel 510 is opened inside the limiting part 500, and a third flow channel 110 is opened inside the connecting part 100. The first end of the second flow channel 510 is connected with the first flow channel 210 through the third flow channel 110, and the second end of the second flow channel 510 can be closed by the second end of the limiting part 500. After the limiting part 500 is broken, the second end of the second flow channel 510 is connected with the extrusion cavity 310, so that the extrusion cavity 310, the second flow channel 510, the third flow channel 110 and the first flow channel 210 are connected in sequence.

[0031] Furthermore, the surface of the pipette tip 300 is marked with scale lines to facilitate the user to identify the content of the biological evidence reagent in the extrusion chamber 310. The reagent content in each enricher is 0 to 5000 u l, and the enricher is vacuum packed, sterilized with ethylene oxide, and stored at room temperature away from light to play an antibacterial and anti-pollution role.

[0032] In the above-mentioned efficient DNA enricher, the biological evidence collection reagent has a certain viscosity, which can effectively adsorb the exfoliated cells and DNA on the surface of the biological evidence, and can well preserve the exfoliated cells and DNA for a certain period of time. Specifically, the biological evidence collection reagent is composed of the following components in molar concentration or mass percentage: 20-50mM (molar concentration) buffer salt, 0.2%-2% (mass percentage) thickener, 0.1%-1% (mass percentage) surfactant, 20-50mM (molar concentration) metal ion chelator, 0.1%-0.5% (mass percentage) antibacterial agent. Among them, the buffer salt can maintain a stable pH value and protect the structure of the cell; the thickener can give the reagent an appropriate viscosity, and at the same time can enhance the specific adsorption of the reagent to the organic component, which is conducive to the adsorption and recovery of the exfoliated cells; the surfactant can enhance the wettability and solubility of the reagent, improve the dissolution and recovery rate of the exfoliated cells adhered to the surface of the carrier, and can make some exfoliated cells adhered to permeable carriers such as paper and cotton cloth fully dissolved and easy to recover; the metal ion chelator eliminates the adhesion phenomenon between the exfoliated cells and the carrier, improves the recovery rate, and protects the integrity of DNA; the antibacterial agent can inhibit the reproduction of microorganisms during the storage of exfoliated cells and DNA samples, and can effectively extend the storage time of the collected samples. Preferably, the thickener is at least one of carbomer, sodium alginate or sodium polyacrylate. The concentration of the buffer salt is 5-20mol / L, and the buffer salt is one of Tris-HCl, phosphate, NaCl, KCl or MgCl; the surfactant is one of sodium dodecyl sulfate, Triton X-100 or Tween-80; the antibacterial agent is potassium sorbate or benzoic acid.

[0033] The method for using the above-mentioned high-efficiency DNA enricher comprises the following steps:

[0034] S1. Remove the sealing cover 600, press the suction head 300 and break the limiting part 500, and continue to squeeze the suction head 300 to deform the squeezing chamber 310 of the high-efficiency DNA enricher, so that the biological evidence collection reagent in the squeezing chamber 310 is released to the biological trace position of the evidence carrier through the connecting tube 200 and the swab 400; wipe the biological trace position with the swab 400, and accelerate the elution of the detached cells and free DNA at the biological trace position through the external force of wiping;

[0035] S2, squeeze the squeezing chamber 310 of the high-efficiency DNA enricher and then release it, suck back the biological evidence collection reagent containing the detached cells and free DNA, and re-cover the sealing cover 600; wipe the small amount of biological evidence collection reagent remaining on the evidence carrier with a dry cotton swab;

[0036] S3. Extract and test the DNA contained in the dry cotton swab, swab 400 and biological evidence collection reagent to obtain a DNA typing result diagram.

[0037] From the above-mentioned usage method, it can be known that the collector of the utility model can be combined with the existing dry and wet two-step wiping method, by releasing the biological evidence collection reagent to the biological trace position, wiping and eluting the exfoliated cells and DNA at the biological trace position, and then absorbing the biological evidence collection reagent back and then wiping the remaining biological evidence collection reagent with a dry cotton swab, so as to extract all the exfoliated cells and DNA on the surface of the evidence carrier as much as possible, thereby increasing the DNA extraction amount, thereby achieving high-quality collection of on-site biological evidence, and is conducive to improving the DNA detection rate.

[0038] Specifically, step S3 uses a magnetic bead method or a silica gel membrane method DNA extraction kit to extract the DNA contained in the dry cotton swab, swab 400 and biological evidence collection reagent. Step S3 tests the extracted DNA according to the following steps: after the extracted DNA is subjected to Nanodrop quantitative detection, multi-color fluorescent labeling and PCR reaction multiple composite amplification are performed using a VFP fluorescence detection kit to detect the polymorphism of the STR loci in the human genomic DNA in the test material evidence and identify the individual; and electrophoresis detection is performed using an ABI genetic analyzer. Specifically, the electrophoresis detection includes the following steps: centrifuging the amplified product at a speed of 2000-5000rpm for 1 to 1min, taking 1 to 10μL of the product or EX25 Allel ic Ladder and mixing it with 0.5 to 3μL AGCUMarker SI Z-500 and 1 to 12μL deionized formamide, denaturing at 50 to 120℃ for 1 to 10min, and then performing ice bath electrophoresis detection.

[0039] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An efficient DNA enricher for field investigation, characterized in that: include A connecting portion (100); A connecting pipe (200), wherein a first end of the connecting pipe (200) is connected to a first end of the connecting portion (100), and a first flow channel (210) is provided in the connecting pipe (200); A suction head (300), wherein a first end of the suction head (300) is connected to a second end of the connecting portion (100), an extrusion cavity (310) is provided inside the suction head (300), and the extrusion cavity (310) is filled with a biological evidence collection reagent; a swab (400), the swab (400) being connected to the second end of the connecting tube (200) and being connected to the first flow channel (210); a limiting portion (500), wherein the limiting portion (500) is located in the extrusion cavity (310), and a first end of the limiting portion (500) is connected to a second end of the connecting portion (100), the limiting portion (500) can block the communication between the extrusion cavity (310) and the first flow channel (210), and the limiting portion (500) can be broken, and after the limiting portion (500) is broken, the extrusion cavity (310) and the first flow channel (210) can be connected to each other; and a sealing cover (600), wherein the sealing cover (600) is sleeved on the outer circumference of the connecting tube (200) and the swab (400), and a first end of the sealing cover (600) is detachably connected to a first end of the connecting portion (100); After the limiting portion (500) is broken, the biological evidence collection reagent in the extrusion cavity (310) can be released into the swab (400) by squeezing the suction head (300), and the biological evidence collection reagent can be recovered into the extrusion cavity (310) through the swab (400) under the action of the negative pressure generated by squeezing the suction head (300).

2. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: A second flow channel (510) is provided inside the limiting portion (500), a first end of the second flow channel (510) is communicated with the first flow channel (210), a second end of the second flow channel (510) can be closed by the second end of the limiting portion (500), and after the limiting portion (500) is broken, the second end of the second flow channel (510) is communicated with the extrusion chamber (310).

3. The efficient DNA enricher for on-site investigation according to claim 2, characterized in that: A third flow channel (110) is provided inside the connecting portion (100), and two ends of the third flow channel (110) are respectively connected to the first flow channel (210) and the second flow channel (510).

4. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: The surface of the suction head (300) is marked with scale lines.

5. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: The suction head (300) is made of soft material.

6. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: The sealing cover (600) is made of a hard material.

7. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: The first end of the sealing cover (600) is threadedly connected to the first end of the connecting portion (100).

8. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: An annular indentation (520) is provided on the outer periphery of the limiting portion (500).

9. The efficient DNA enricher for on-site investigation according to claim 1, characterized in that: The first end of the suction head (300) has a sleeve connection portion (320), and the sleeve connection portion (320) is sleeved on the outer periphery of the first end of the connecting portion (100).

10. The efficient DNA enricher for on-site investigation according to claim 9, characterized in that: A sealing ring (700) is provided between the sleeve connection portion (320) and the connecting portion (100), and inner and outer sides of the sealing ring (700) respectively abut against the connecting portion (100) and the sleeve connection portion (320).

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