A sodium silicate silica gel cellulose membrane, a preparation method and application thereof
By preparing sodium silicate silica cellulose membranes in the laboratory, the problem of high production cost of silica membranes was solved, achieving low-cost and efficient nucleic acid purification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUNAN UNIV OF SCI & ENG
- Filing Date
- 2023-11-16
- Publication Date
- 2026-05-29
AI Technical Summary
In the existing technology, the production cost of silica membranes is high, and they cannot be made in the laboratory. Furthermore, existing silica membranes have long operation time and low efficiency in nucleic acid purification.
A viscous sodium silicate solution was precipitated by mixing a saturated sodium silicate aqueous solution with dimethylformamide. This solution was then mixed with silica gel and bonded to a cellulose membrane. After natural drying, a sodium silicate silicate cellulose membrane was prepared. After treatment with ammonium chloride, it was used for nucleic acid adsorption.
This invention enables the low-cost preparation of sodium silicate, silica gel, and cellulose membranes in ordinary laboratories, which can replace commercially available silica membranes, shorten nucleic acid processing time, and improve extraction efficiency.
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Figure CN117463164B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of silica membrane technology, specifically relating to a sodium silicate silica cellulose membrane, its preparation method, and its application. Background Technology
[0002] Silica membranes are adsorbent materials used in nucleic acid purification kits to adsorb nucleic acids. They are surface-modified with silica and utilize the high salt and low pH properties of silica hydroxyl groups to adsorb different nucleic acids. This allows for the artificial adjustment of the formula to achieve the purification and recovery of DNA, RNA, and plasmids.
[0003] In existing technologies, silicone films are generally produced by mechanically pressing silicone granules and pulp in a certain ratio, followed by baking to form a film, which results in high production costs. Since most laboratories lack papermaking machinery, they cannot produce silicone films and must purchase them. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a sodium silicate silica cellulose membrane, its preparation method, and its applications. The sodium silicate silica cellulose membrane provided by this invention can be prepared in a common laboratory, and the prepared sodium silicate silica cellulose membrane has the characteristic of adsorbing nucleic acids, and can replace commercially available silica membranes to prepare relatively pure nucleic acid samples.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] This invention provides a method for preparing a sodium silicate silicate cellulose membrane, comprising the following steps:
[0007] A saturated aqueous solution of sodium silicate is mixed with dimethylformamide to precipitate the precipitate, resulting in a viscous sodium silicate solution.
[0008] The viscous sodium silicate solution was mixed with silica gel to obtain a silica gel suspension;
[0009] A sodium silicate silica cellulose membrane was obtained by bonding a cellulose membrane with a silica gel suspension and then allowing it to dry naturally at room temperature.
[0010] Preferably, the volume ratio of the saturated sodium silicate aqueous solution to dimethylformamide is 1:1.
[0011] Preferably, the precipitation time is 10-15 minutes.
[0012] Preferably, the preparation steps of the cellulose membrane include: immersing filter paper sequentially in nitric acid solution and sodium hydroxide solution to obtain the cellulose membrane.
[0013] Preferably, the volume concentration of the nitric acid solution is 32.5-34%; the soaking time in the nitric acid solution is 4-5 hours; the concentration of the sodium hydroxide solution is 2 mol / L; and the soaking time in the sodium hydroxide solution is 3-4 hours.
[0014] Preferably, after soaking in the nitric acid solution and sodium hydroxide solution, the process further includes soaking and drying the obtained cellulose membrane in clean water in sequence; the soaking time in clean water is 5 to 10 minutes; the drying time is 1 to 2 hours, and the temperature is 65°C.
[0015] Preferably, the mass ratio of the silica gel to the volume ratio of the viscous sodium silicate solution is 8g:100mL.
[0016] Preferably, the natural drying time at room temperature is 8 to 9 days.
[0017] The present invention provides a sodium silicate cellulose membrane prepared by the preparation method described above, comprising silica, silicon dioxide and cellulose membrane; wherein the cellulose membrane and silica are bonded together by silica.
[0018] This invention provides the application of the sodium silicate silicate cellulose membrane described above in the adsorption of nucleic acids.
[0019] This invention provides a method for preparing a sodium silicate-silica-cellulose membrane, comprising the following steps: mixing a saturated aqueous sodium silicate solution with dimethylformamide to precipitate and obtain a viscous sodium silicate solution; mixing the viscous sodium silicate solution with silica gel to obtain a silica gel suspension; bonding a cellulose membrane with the silica gel suspension and drying it naturally at room temperature to obtain a sodium silicate-silica-cellulose membrane. This invention uses dimethylformamide to precipitate a saturated aqueous sodium silicate solution to obtain a viscous sodium silicate solution; immersing the viscous sodium silicate solution between plant fibers allows the sodium silicate to react with carbon dioxide in the air to produce an amorphous silica gel, which, after natural dehydration and drying, transforms into silica, enabling a tight bond between the silica gel powder and the cellulose membrane; drying at room temperature allows the viscous sodium silicate solution to penetrate more deeply into the plant fiber cells, resulting in stronger adhesion between the cellulose membranes and eliminating gaps between fiber cells. The preparation method provided by this invention is simple to operate, low in cost, and can be used in ordinary laboratory production applications with limited funds.
[0020] The sodium silicate silica cellulose membrane prepared by this invention has the property of adsorbing nucleic acids after being treated with ammonium chloride. It can replace commercially available silica membranes to prepare relatively pure nucleic acid samples. It also has a shorter operation time and higher extraction efficiency than using silica particles, silica particles and calcium carbonate powder alone to adsorb nucleic acids in nucleic acid extraction solution. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is an image of the sodium silicate silica cellulose membrane prepared in Example 1 adsorbing nucleic acids. Detailed Implementation
[0023] This invention provides a method for preparing a sodium silicate silicate cellulose membrane, comprising the following steps:
[0024] A saturated aqueous solution of sodium silicate is mixed with dimethylformamide to precipitate the precipitate, resulting in a viscous sodium silicate solution.
[0025] The viscous sodium silicate solution was mixed with silica gel to obtain a silica gel suspension;
[0026] A sodium silicate silica cellulose membrane was obtained by bonding a cellulose membrane with a silica gel suspension and then allowing it to dry naturally at room temperature.
[0027] Unless otherwise specified, all materials and equipment used in this invention are commercially available products in the field.
[0028] In this invention, a saturated aqueous solution of sodium silicate is mixed with dimethylformamide to precipitate the precipitate, thereby obtaining a viscous sodium silicate solution.
[0029] In this invention, the volume ratio of the saturated sodium silicate aqueous solution to dimethylformamide is preferably 1:1. In this invention, the mixing is preferably performed by repeatedly inverting and shaking; the mixing time is preferably 1 minute. In this invention, the precipitation is preferably allowed to stand at room temperature; the precipitation time is preferably 10-15 minutes. After the precipitation is complete, the supernatant is preferably removed to obtain the viscous sodium silicate solution. In this invention, the supernatant is dimethylformamide and an aqueous solution containing unprecipitated sodium silicate, and is not viscous.
[0030] Since the purchased sodium silicate is soluble in water, even when a saturated sodium silicate solution is prepared, it is not viscous. Therefore, this invention mixes dimethylformamide with an equal volume of saturated sodium silicate aqueous solution, causing some of the silicate ions in the sodium silicate molecules to dehydrate and polymerize, precipitating out a transparent sodium silicate solution that is viscous.
[0031] After obtaining the viscous sodium silicate solution, the present invention mixes the viscous sodium silicate solution with silica gel to obtain a silica gel suspension.
[0032] In this invention, the preferred mass ratio of the silica gel to the volume of the viscous sodium silicate solution is 8g:100mL.
[0033] After obtaining the silica gel suspension, the present invention binds the cellulose membrane with the silica gel suspension and dries it naturally at room temperature to obtain a sodium silicate silica gel cellulose membrane.
[0034] This invention does not have specific requirements regarding the source of the cellulose membrane; commercially available cellulose membranes or those prepared in-house can be used. Preparing in-house is preferred to reduce costs. When preparing in-house, the cellulose membrane preparation steps preferably include: sequentially immersing filter paper in nitric acid solution and sodium hydroxide solution to obtain the cellulose membrane.
[0035] In this invention, the filter paper is preferably a qualitative filter paper with a diameter of 12.5 cm; the volume concentration of the nitric acid solution is preferably 32.5-34%, more preferably 33-34%; and the soaking time in the nitric acid solution is preferably 4-5 hours. Soaking the filter paper in the nitric acid solution removes inorganic substances such as adhesive and calcium carbonate, as well as small organic molecules, from the filter paper, making the fibers looser and increasing the permeability of the filter paper.
[0036] In this invention, the concentration of the sodium hydroxide solution is preferably 2 mol / L; the soaking time in the sodium hydroxide solution is preferably 3-4 hours, more preferably 3.2-3.8 hours. Soaking the filter paper in the sodium hydroxide solution in this invention further loosens the filter paper, resulting in a cellulose membrane.
[0037] After soaking in the nitric acid solution and sodium hydroxide solution, the present invention preferably further includes soaking and drying the obtained cellulose membrane sequentially in clean water; the soaking time in clean water is preferably 5-10 minutes, more preferably 6-8 minutes; the drying is preferably carried out in an oven, the drying time is preferably 1-2 hours, and the temperature is preferably 65°C. The present invention removes the nitric acid solution and sodium hydroxide solution by soaking the obtained cellulose membrane in clean water.
[0038] In this invention, the cellulose membrane used for bonding preferably comprises at least two layers. When the cellulose membrane has two layers, the bonding process preferably includes: placing one layer of the cellulose membrane flat on a glass plate, then using a pipette to draw silica gel suspension and evenly distribute it on the cellulose membrane, covering it with the other layer of cellulose membrane, and then pressing it with a glass plate. This invention does not have particular requirements regarding the pressure and time of the glass plate pressing; the goal is to ensure that the silica gel suspension is evenly distributed on the surface of the cellulose membrane, removes air bubbles, and prevents it from flowing out of the cellulose membrane.
[0039] After bonding is completed, the glass plate used for pressing is preferably removed, and the resulting sodium silicate silicate cellulose membrane is placed on paper and allowed to air dry at room temperature for 8-9 days. During the air drying process, it is preferred that the membrane be turned over every 30 minutes within the first 4-5 hours, and then only once a day thereafter, to prevent the sodium silicate silicate cellulose membrane from sticking tightly to the paper. In this invention, a viscous sodium silicate solution is immersed between plant fibers. Some of the sodium silicate on the cellulose membrane reacts with carbon dioxide in the air to form an amorphous silica gel, which, after natural dehydration and drying, transforms into silica, enabling a tight bond between the silica powder and the cellulose film.
[0040] The preparation method provided by this invention is simple to operate and low in cost, and can be used for ordinary laboratory production applications with insufficient funds.
[0041] The present invention provides a sodium silicate cellulose membrane prepared by the preparation method described above, comprising silica, silicon dioxide and cellulose membrane; wherein the cellulose membrane and silica are bonded together by silica.
[0042] This invention provides the application of the sodium silicate silicate cellulose membrane described above in the adsorption of nucleic acids.
[0043] Before adsorbing nucleic acids, the present invention preferably soaks the sodium silicate silica cellulose membrane in an ammonium chloride solution and then dries it. In the present invention, the ammonium chloride solution is preferably obtained by dissolving ammonium chloride in water; the concentration of the ammonium chloride solution is preferably 2 mol / L; the soaking time is preferably 2-3 minutes; the drying temperature is preferably 65°C, and the drying time is preferably 20 minutes. After the above-mentioned 8-9 days of natural drying, only some of the sodium silicate on the cellulose membrane is converted into silica, leaving most of the dried sodium silicate between the fiber cells. The present invention, by soaking the sodium silicate silica cellulose membrane in an ammonium chloride solution, can convert the sodium silicate between the fiber cells into silica gel.
[0044] This invention does not have special requirements for the process of adsorbing nucleic acids; a process well-known in the art can be used. In an embodiment of this invention, after drying, a sodium silicate silica cellulose membrane is prepared into a disc using a 0.7 cm diameter punch. Eight to ten discs are placed in a collection column with the silica membrane removed and pressed tightly with a pressure ring to collect nucleic acid components from plant and bacterial cells. In this invention, the nucleic acid preferably includes at least one of RNA, plasmids, and DNA fragments. The sodium silicate silica cellulose membrane prepared by this invention, after treatment with ammonium chloride, has the characteristic of adsorbing nucleic acids. It can replace commercially available silica membranes to prepare relatively pure nucleic acid samples, and the operation time is shorter and the extraction efficiency is higher than that of adsorbing nucleic acids in nucleic acid extraction solution using silica particles, silica particles, and calcium carbonate powder alone.
[0045] To further illustrate the present invention, the sodium silicate silica cellulose membrane, its preparation method, and its application provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.
[0046] Example 1
[0047] Prepare a 36% saturated sodium silicate solution using distilled water. Take 5 mL of the solution and place it in a 10 mL capped test tube. Add an equal volume of dimethylformamide solution to the test tube and shake the mixture repeatedly for 1 min. Let the mixture stand at room temperature for 10 min and remove the supernatant using a pipette to obtain a viscous sodium silicate solution.
[0048] The viscous sodium silicate solution is mixed with silica gel to obtain a silica gel suspension, wherein the mass ratio of silica gel to the volume ratio of the viscous sodium silicate solution in the silica gel suspension is 8 g: 100 mL.
[0049] Take a 12.5cm diameter qualitative filter paper (standard number: GB / 1915-80, Zhejiang Wenzhou Dongtou Shuangpu Middle School Chemical Reagent Factory), cut it into 4 equal parts, and place each part into a 6cm diameter petri dish containing 20mL of 33.5% nitric acid solution for 4.5h. Then transfer the filter paper to a 2mol / L sodium hydroxide solution and soak for 3.5h, separating each filter paper into two cellulose membranes. Then transfer the resulting cellulose membranes to water and soak for 7min. Finally, transfer the resulting cellulose membranes to a petri dish and bake in a 65℃ oven for 1h to obtain a dried cellulose membrane.
[0050] One layer of dry cellulose membrane was laid flat on a glass plate. Then, a silica gel suspension was drawn up with a pipette and evenly placed on the cellulose membrane. Another layer of cellulose membrane was then placed on top and pressed with a glass plate to ensure that the silica gel suspension was evenly distributed on the surface of the cellulose membrane, removing any air bubbles and preventing it from flowing out. The glass plate was then removed, and after 10 minutes, the wet sodium silicate silica gel cellulose membrane was moved and laid flat on A4 paper. It was then allowed to air dry at room temperature for 9 days. During the air drying process, the membrane was turned over every 30 minutes during the first 4 hours, and only once a day thereafter, to prevent the cellulose membrane from sticking tightly to the paper. Finally, the sodium silicate silica gel cellulose membrane was transferred to a clean container at room temperature for storage.
[0051] Application Example 1
[0052] Take the sodium silicate silica cellulose membrane prepared in Example 1 and place it in a petri dish containing 20 mL of 2 mol / L ammonium chloride solution for 2 min. Then transfer the cellulose membrane onto A4 paper and dry it in a 65°C oven for 20 min. Subsequently, use a 0.7 cm diameter punch to prepare the sodium silicate silica cellulose membrane into discs. Place 10 discs into a discarded collection column with the silica membrane removed and press them with a membrane clamp to collect nucleic acid components from plant cells and bacterial cells.
[0053] Figure 1 This is an image of the sodium silicate silica cellulose membrane prepared in Example 1 adsorbing nucleic acids. Figure 1 In the image, A represents the RNA component of tea leaves; B represents the pUCm-T recombinant vector in *E. coli* linked with a foreign DNA fragment; and C represents the DNA fragment in the agarose gel. Figure 1 As shown in Figure A, it can adsorb RNA from the nucleic acid extract of tea leaves obtained by the Trizol method after extraction with phenol, chloroform, and isoamyl alcohol; as shown in Figure A. Figure 1 As shown in Figure B, it can recover plasmids extracted from E. coli using a plasmid extraction kit; such as Figure 1 As shown in Figure C, DNA fragments extracted from agarose gel using an agarose gel extraction kit can be recovered.
[0054] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for preparing a sodium silicate silica gel cellulose membrane, characterized in that, Includes the following steps: A saturated aqueous solution of sodium silicate is mixed with dimethylformamide to precipitate the precipitate, resulting in a viscous sodium silicate solution. The volume ratio of the saturated aqueous solution of sodium silicate to dimethylformamide is 1:
1. The precipitation time is 10-15 minutes. The viscous sodium silicate solution was mixed with silica gel to obtain a silica gel suspension; A sodium silicate silica cellulose membrane was obtained by bonding a cellulose membrane with a silica gel suspension and then allowing it to dry naturally at room temperature.
2. The preparation method according to claim 1, characterized in that, The preparation steps of the cellulose membrane include: immersing filter paper in nitric acid solution and sodium hydroxide solution in sequence to obtain the cellulose membrane.
3. The preparation method according to claim 2, characterized in that, The volume concentration of the nitric acid solution is 32.5-34%; the soaking time in the nitric acid solution is 4-5 hours; the concentration of the sodium hydroxide solution is 2 mol / L; the soaking time in the sodium hydroxide solution is 3-4 hours.
4. The preparation method according to claim 2 or 3, characterized in that, After soaking in the nitric acid solution and sodium hydroxide solution, the process further includes soaking the obtained cellulose membrane in clean water and drying it in sequence; the soaking time in clean water is 5-10 minutes; the drying time is 1-2 hours, and the temperature is 65°C.
5. The preparation method according to claim 1, characterized in that, The mass ratio of the silica gel to the volume ratio of the viscous sodium silicate solution is 8g:100mL.
6. The preparation method according to claim 1, characterized in that, The air-drying time at room temperature is 8 to 9 days.
7. The sodium silicate silica cellulose membrane prepared by the preparation method according to any one of claims 1 to 6, characterized in that, It includes silicone, silica, and a cellulose membrane; the cellulose membrane and silicone are bonded together by silica.
8. The application of the sodium silicate silica gel cellulose membrane according to claim 7 in the adsorption of nucleic acids.