CN114130373B - Nitrocellulose membrane and preparation method thereof - Google Patents
Nitrocellulose membrane and preparation method thereof Download PDFInfo
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- CN114130373B CN114130373B CN202111482600.2A CN202111482600A CN114130373B CN 114130373 B CN114130373 B CN 114130373B CN 202111482600 A CN202111482600 A CN 202111482600A CN 114130373 B CN114130373 B CN 114130373B
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- 229920001220 nitrocellulos Polymers 0.000 title claims abstract description 184
- 239000000020 Nitrocellulose Substances 0.000 title claims abstract description 180
- 239000012528 membrane Substances 0.000 title claims abstract description 151
- 238000002360 preparation method Methods 0.000 title claims description 21
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 claims abstract description 48
- 229960001545 hydrotalcite Drugs 0.000 claims abstract description 48
- 229910001701 hydrotalcite Inorganic materials 0.000 claims abstract description 48
- 239000002904 solvent Substances 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 29
- 239000002245 particle Substances 0.000 claims abstract description 20
- 239000000126 substance Substances 0.000 claims abstract description 18
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 14
- 239000006184 cosolvent Substances 0.000 claims abstract description 13
- 239000002994 raw material Substances 0.000 claims abstract description 4
- 239000000243 solution Substances 0.000 claims description 27
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 20
- 238000003756 stirring Methods 0.000 claims description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 13
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 13
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- 238000007790 scraping Methods 0.000 claims description 12
- 238000007493 shaping process Methods 0.000 claims description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 10
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 10
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- 229920002492 poly(sulfone) Polymers 0.000 claims description 10
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 7
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 239000005341 toughened glass Substances 0.000 claims description 5
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- 238000000465 moulding Methods 0.000 description 6
- 102000004169 proteins and genes Human genes 0.000 description 6
- 108090000623 proteins and genes Proteins 0.000 description 6
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- 238000004113 cell culture Methods 0.000 description 2
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- RXKJFZQQPQGTFL-UHFFFAOYSA-N dihydroxyacetone Chemical class OCC(=O)CO RXKJFZQQPQGTFL-UHFFFAOYSA-N 0.000 description 2
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- 239000004695 Polyether sulfone Substances 0.000 description 1
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- 102000036639 antigens Human genes 0.000 description 1
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- 230000001580 bacterial effect Effects 0.000 description 1
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- 239000000969 carrier Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/26—Synthetic macromolecular compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D15/08—Selective adsorption, e.g. chromatography
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
- B01J20/12—Naturally occurring clays or bleaching earth
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
- B01J20/28033—Membrane, sheet, cloth, pad, lamellar or mat
- B01J20/28038—Membranes or mats made from fibers or filaments
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/281—Sorbents specially adapted for preparative, analytical or investigative chromatography
- B01J20/282—Porous sorbents
- B01J20/285—Porous sorbents based on polymers
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- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Dispersion Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a nitrocellulose membrane, which is prepared from nitrocellulose membrane solution, wherein the nitrocellulose membrane solution comprises the following raw materials in parts by weight: 20-21 parts of a solvent; 0.2 to 0.3 part of cosolvent; 2-3 parts of non-solvent; 5-6 parts of a forming agent; 0.02-0.08 part of hydrotalcite; 3-4 parts of nitrocellulose particles. According to the nitrocellulose membrane prepared by the invention, the added hydrotalcite has a special layered structure, so that functional polymer substances can be put into the gaps of the hydrotalcite, the hydrotalcite is supported and the structure of the hydrotalcite is not changed, the nitrocellulose membrane with a porous supporting layer is perfect in effective pore diameter, the hydrophilicity of the nitrocellulose membrane is effectively improved, and meanwhile, the hydrotalcite has a strong binding force, and the problem that blended particles are unevenly distributed and are easy to agglomerate can be solved. The pore diameter is effectively perfect, which is helpful to reduce the non-anisotropic binding probability and reduce the false positive generated in the using process of using the nitrocellulose membrane as a carrier.
Description
Technical Field
The invention relates to the technical field of cellulose films, in particular to a nitrocellulose membrane and a preparation method thereof.
Background
Nitrocellulose (NC) membrane is the earliest commercialized microporous filter membrane, has extremely strong nonspecific adsorption capacity to macromolecular substances such as protein, nucleic acid and the like, and is widely applied in the fields of molecular hybridization, immunoblotting, cell culture, medical diagnosis and the like. The carrier for the C/T line in the colloidal test paper is the place where the reaction between the antibody and the antigen occurs; nitrocellulose membrane is the most widely used transfer medium for western blotting, has strong binding capacity to proteins, and is suitable for various color development methods including isotope, chemiluminescence, conventional color development, staining and fluorescent color development; the background is low and the signal to noise ratio is high.
The nitrocellulose membrane is also one of the main carriers of novel coronavirus antibody detection reagents, and the needs of the detection reagents are increasingly increased along with the long-time spread of epidemic situations, so that only one or two enterprises in China can produce the nitrocellulose membrane at present, and most of the enterprises depend on import and market conditions are in supply and demand.
The binding of nitrocellulose membrane to protein is currently hypothesized to rely on the use of hydrophilic binding of the membrane and mutual electrostatic forces to maintain long-term binding, which is indicative of the effects of nitrocellulose membrane pore size on binding forces and hydrophilicity. As the pore size of the membrane decreases, the actual available surface area of the membrane increases, as does the amount of membrane-bound protein, and the parameter that measures the surface area is the surface area ratio. In addition, the method comprises the following steps. The smaller the membrane pore diameter, the lower the chromatography speed, and the longer the time for the gold-labeled complex to pass through the T line, the more fully the reaction. Although the smaller the nitrocellulose membrane pore size, the higher the sensitivity; but also slows the running board down and increases the chance of non-specific binding, i.e. the higher the false positive. Therefore, it is necessary to select a nitrocellulose membrane suitable for the actual detection reaction, and to find a suitable equilibrium point, that is, to reduce the possibility of non-specific binding while the reaction sensitivity is high.
At present, the main preparation process of the nitrocellulose membrane comprises the following steps: preparing film slurry, spreading the film by a roller, drying, forming, rolling and cutting.
In the preparation process of adding the surfactant treatment fluid, a nitrocellulose membrane is soaked in the treatment fluid, the surface of the nitrocellulose membrane is treated, and in order to ensure the continuity of membrane production, the treatment fluid is continuously replaced with new treatment fluid according to the actual condition of production, and solutes are timely supplemented to the treatment fluid, so that the impurities are reduced. When the treatment liquid infiltrating the NC film in the liquid tank is replaced each time, in order to not influence production and ensure production efficiency, only 66% of the liquid tank treatment liquid can be replaced, so that impurities contained in the remaining non-replaced treatment liquid can not be discharged in time, and the non-replaced treatment liquid is subjected to continuous uninterrupted production and use, so that impurities of the treatment liquid are easily attached to the surface of the nitrocellulose film; meanwhile, when the nitrocellulose membrane is produced, a large number of bubbles exist on the surface of the nitrocellulose membrane, and the quality of the nitrocellulose membrane is affected.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a nitrocellulose membrane with good hydrophilicity and proper pore diameter and a preparation method thereof.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the invention provides a nitrocellulose membrane, which is prepared from nitrocellulose membrane solution, wherein the nitrocellulose membrane solution comprises the following raw materials in parts by weight:
through the technical scheme, the nitrocellulose particles can be fully stirred, can be fully dissolved in the solvent, reduce impurities of the NC film after molding, and the cosolvent can help different components to be fully dissolved, and the non-solvent is mainly used as a high-molecular surfactant, so that the molding agent is added to help the final shaping of the NC film. The membrane liquid prepared by the method has the advantages of easily available raw materials and simple preparation.
The hydrotalcite is added based on a special layered structure, so that functional polymer substances can be added into the gaps of hydrotalcite, the hydrotalcite is spread and the structure of the hydrotalcite is not changed, the nitrocellulose membrane of a porous supporting layer is perfected, the effective aperture is improved, the hydrophilicity of the nitrocellulose membrane is effectively improved, meanwhile, the hydrotalcite has stronger binding force, and the problem that the blend particles are unevenly distributed and are easy to agglomerate can be solved.
Preferably, the solvent comprises one or two of N, N-dimethylformamide and N, N-dimethylacetamide in any weight ratio. As aprotic high-polarity solvent, the solvent has strong dissolving power, high thermal stability and stable chemical property, and meanwhile, the range of soluble substances is wide, and the compound molecules can be activated.
Preferably, the cosolvent comprises one or two of acetone and butanone in any weight ratio. The organic solvent can be mixed with a main solvent at will, is the simplest ketone in the saturated aliphatic ketone series, has higher polarity, and can dissolve acetate fibers and nitrocellulose fibers.
Preferably, the non-solvent comprises one or any weight ratio of polyvinylpyrrolidone and cross-linked polyvinylpyrrolidone. As a polymer surfactant, the polymer surfactant has film forming property, solubilization or agglomeration, has good affinity with a plurality of organic matters, and improves the hydrophilicity.
Preferably, the shaping agent comprises one or more of polysulphone, polyarylsulphone and polyethersulphone. The polymer has excellent mechanical properties, and even at high temperature, the excellent mechanical properties are outstanding advantages, and the polymer has high thermal stability, hydrolysis resistance, good dimensional stability and small molding shrinkage, and plays an important molding role in the system of the invention.
Nitrocellulose particles are a very common organic chemical, and under certain conditions, are dissolved in a solvent and co-solvent to form a slurry, and in this slurry, a certain proportion of reagents are added to adjust the properties of the final film, such reagents mainly comprising surfactants, high molecular polymers, shaping agents and the like are dissolved in a buffer system.
The invention also provides a preparation method of the nitrocellulose membrane, which comprises the following steps:
step one, preparing a nitrocellulose membrane solution according to the proportioning of each substance;
step two, defoaming the nitrocellulose membrane solution in the step one to obtain nitrocellulose membrane casting solution;
scraping the concentrated solution of the nitrocellulose membrane after the deaeration in the step two to form a membrane, wiping the membrane by absolute ethyl alcohol by using a scraper tool, cleaning the membrane by pure water, finally drying the membrane to obtain a clean toughened glass plate, and scraping the membrane on the clean toughened glass plate;
step four, shaping the nitrocellulose membrane formed by scraping the membrane in the step three, putting the nitrocellulose membrane into a gel bath with a fixed temperature, and processing the nitrocellulose membrane to obtain the shaped nitrocellulose membrane;
and fifthly, drying the shaped nitrocellulose membrane in the fourth step to obtain a nitrocellulose membrane finished product.
Through adopting foretell technical scheme, nitrocellulose membrane liquid is in the preparation in-process, fully stirs, through temperature and the stirring time of control stirring in-process, effectually alleviateed NC membrane's bubble content, and the membrane liquid of preparing is through standing the deaeration treatment, has effectually avoided NC membrane surface to produce a large amount of bubbles, has alleviateed the influence to its quality. NC films with different thicknesses can be obtained by adjusting the distance between the scraper and the glass plate in the film scraping and over-forming process, the NC films are gradually solidified into formed NC films by controlling the temperature of a gel bath, the formed NC films are placed into deionized water, redundant impurities can be removed, and finally, the generation of bacteria on the surfaces of the NC films can be effectively reduced in the vacuum drying process, so that the quality of nitrocellulose films is ensured.
Preferably, in the preparation of the nitrocellulose membrane solution in the step one, the stirring temperature is between 60 and 65 ℃ and the stirring time is more than 24 hours.
Through the technical scheme, the nitrocellulose membrane liquid can be fully stirred, and all the components are completely dissolved. The temperature is 60-65 ℃, and the stirring time is more than 24 hours, so that hydrotalcite can be fully supported by other components, a nitrocellulose membrane with a multi-hollow supporting layer is formed, the effective aperture of the NC membrane is improved, and the hydrophilicity is improved.
Preferably, the nitrocellulose membrane solution needs to be subjected to standing and defoaming for more than 24 hours.
Through the technical scheme, the nitrocellulose membrane liquid is fully dissolved after being fully stirred, and is subjected to standing and defoaming treatment in a drying environment, so that a large number of bubbles on the surface of the NC membrane are effectively avoided, and the influence on the quality of the NC membrane is reduced.
Preferably, the ethanol content of the gel bath is between 30 and 40 percent, the temperature is between 30 and 35 ℃, and the time is more than 1min. In the doctor blade forming process of the doctor blade, the thickness of the nitrocellulose membrane is controlled by adjusting the distance between the doctor blade and the glass plate. The ethanol content is controlled in the gel bath, so that the film forming speed is controlled, the pore diameter of the NC film cannot be increased in the process, the film porosity is improved, the temperature is controlled, unreacted substances in the nitrocellulose film forming process are washed away, the water temperature is too high, the film forming speed is low, the gel bath time is too short, and the unreacted substances in the NC film cannot be sufficiently washed away.
Through the technical scheme, the thickness of the nitrocellulose membrane can be controlled by adjusting the distance between the scraper and the toughened glass plate, so that the requirements of preparing NC membranes with different thicknesses are met, and more selectivity is provided.
Preferably, the nitrocellulose membrane is released from the gel bath and is allowed to stand in deionized water for a period of time greater than 4 hours.
Through the technical scheme, the NC film after gel bath shaping is peeled off and put into deionized water, unreacted substances or impurities attached to the NC film can be removed, and meanwhile, bacterial pollutants in the air are prevented from being contacted in a wet state, so that the NC film is polluted, and the quality of the NC film is influenced.
Preferably, the nitrocellulose membrane which is left in deionized water is taken out after leaving to stand and dried at a temperature of 44 to 50 ℃.
Through the technical scheme, the NC film taken out of the deionized water is placed in the vacuum drying oven, so that air is isolated, the influence of humidity in the air on the NC film is avoided, and the content of bubbles on the surface of the NC film is reduced.
Preferably, the preparation of the nitrocellulose membrane solution comprises the following steps:
step one, mixing a proportioning amount of the solvent and nitrocellulose particles with hydrotalcite, and then stirring at room temperature;
and step two, adding the cosolvent, the forming agent and the non-solvent into the mixed solution, and continuously stirring at the temperature of 60-65 ℃ for 24-36 h.
According to the technical scheme, the solvent, the hydrotalcite and the nitrocellulose particles are mixed and stirred, so that more uniform mixing is facilitated, the solvent, the forming agent and the non-solvent are added to be continuously stirred after mixing, the dissolution of the nitrocellulose is facilitated, the impurities of the NC film after forming are reduced, the cosolvent can be favorable for obtaining sufficient dissolution of different components, the non-solvent is mainly used as a high-molecular surfactant, and the addition of the forming agent is favorable for shaping of the NC film finally.
In summary, the invention has the following beneficial effects:
1. according to the nitrocellulose membrane prepared by the invention, hydrotalcite is added in the hydrotalcite creatively, and functional polymer substances can be put into the gaps of the hydrotalcite by utilizing the special layered structure of the hydrotalcite, so that the hydrotalcite is supported and the structure of the hydrotalcite is not changed, the nitrocellulose membrane with a porous supporting layer is perfect in effective aperture, and the hydrophilicity of the nitrocellulose membrane is effectively improved.
2. In the process of preparing the nitrocellulose membrane, under certain conditions, nitrocellulose particles are dissolved under the action of a solvent and a cosolvent to form mixed slurry, and a certain proportion of reagent is added into the slurry to adjust the properties of the finally formed membrane, wherein the reagent mainly comprises a surfactant, a high molecular polymer, a forming agent and the like which are dissolved in a buffer system. The fully stirred hydrophilic hydrotalcite can be uniformly distributed in the NC membrane, so that the membrane structure is smoother, the pore channels are uniformly distributed, and the porosity is improved.
3. In the invention, the solvent, the cosolvent, the surfactant and the forming agent are selected, so that the components can be fully dissolved and mixed in the preparation process, and the addition of the surfactant is favorable for having film forming property, solubilization or agglomeration and improving the hydrophilicity of the NC film. Because the hydrotalcite has a layered structure, the intercalation property is shown on the spatial structure, and the macromolecular substances in the mixing process can enter the interlayer pores of the hydrotalcite, so that the hydrotalcite is spread, the spatial structure is not changed, and the hydrophilicity of the NC film is greatly increased.
4. In the process of preparing the membrane liquid, the method has three links for reducing the influence of NC membrane bubbles: firstly, stirring time is longer than 24 hours, so that the components are fully mixed, and the generation of bubbles is reduced; secondly, standing the prepared membrane liquid for more than 24 hours; thirdly, the shaping link is arranged in a vacuum drying oven, so that a large number of bubbles are prevented from being generated on the surface of the NC film.
5. Hydrotalcite itself has flame retardancy, and can improve the inflammability of nitrocellulose particles. The hydrotalcite has a special layered structure, and can enable functional polymer substances to enter the gaps of the hydrotalcite, so that the hydrotalcite is spread and the structure of the hydrotalcite is not changed, the nitrocellulose membrane of the porous supporting layer is perfected, the effective aperture is reduced, the non-specific binding probability in the use process of the hydrotalcite and the NC membrane is reduced, the false positive probability of detection is reduced, the hydrophilicity of the nitrocellulose membrane is effectively improved, meanwhile, the hydrotalcite has stronger binding force, and the problem that the blending particles are unevenly distributed and are easy to agglomerate can be solved.
It should be understood that all combinations of the foregoing concepts, as well as additional concepts described in more detail below, may be considered a part of the inventive subject matter of the present disclosure as long as such concepts are not mutually inconsistent.
Other additional aspects of the invention, such as features and/or advantages of the exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of the embodiments according to the teachings of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention are clearly and completely described below. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present invention fall within the protection scope of the present invention. Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
Nitrocellulose (NC) membrane is the earliest commercialized microporous filter membrane, has extremely strong nonspecific adsorption capacity to macromolecular substances such as proteins, nucleic acids and the like, and is widely applied to the fields of molecular hybridization, immunoblotting, cell culture, medical diagnosis and the like. The NC film mainly comprises the following preparation processes: preparing membrane slurry, paving the membrane by a roller, drying and forming, winding and slitting, wherein the NC membrane obtained by the production process is easy to generate bubbles and impurities, and simultaneously the aperture of the NC membrane is not easy to control. NC membranes are obtained herein using steps that are effective in controlling NC membrane pore size and help to reduce the chance of non-specific binding during detection and reduce false positives in the detection results.
The preparation method of the NC film comprises the following steps:
step one, preparing a nitrocellulose membrane solution;
step two, defoaming the nitrocellulose membrane solution in the step one to obtain a nitrocellulose membrane concentrated solution;
scraping the concentrated solution of the nitrocellulose membrane after the deaeration in the step two to form a membrane, and scraping the membrane on a clean toughened glass plate by using a scraper tool;
step four, shaping the nitrocellulose membrane formed by scraping the membrane in the step three, putting the nitrocellulose membrane into a gel water bath with a fixed temperature, and performing water treatment to obtain the shaped nitrocellulose membrane;
and fifthly, drying the shaped nitrocellulose membrane in the step four.
The nitrocellulose membrane solution is prepared from the following substances in parts by weight:
the solvent comprises one or two of N, N-dimethylformamide and N, N-dimethylacetamide in any weight ratio, and is used as an aprotic high-polarity solvent, so that the solvent has strong dissolving power, high thermal stability and stable chemical property, and meanwhile, the range of soluble substances is wide, and the compound molecules can be activated.
The cosolvent comprises one or two of acetone and butanone in any weight ratio, can be mixed with the main solvent at will, is used as the simplest ketone in the saturated aliphatic ketone series, has higher polarity, and can dissolve acetate fibers and nitrocellulose fibers.
The non-solvent comprises one or two of polyvinylpyrrolidone and cross-linked polyvinylpyrrolidone in any weight ratio. As a polymer surfactant, the polymer surfactant has film forming property, solubilization or agglomeration, has good affinity with a plurality of organic matters, and improves the hydrophilicity.
The forming agent comprises one or more of polysulfone, polyarylsulfone and polyethersulfone. The polymer has excellent mechanical properties, and even at high temperature, the excellent mechanical properties are outstanding advantages, and the polymer has high thermal stability, hydrolysis resistance, good dimensional stability and small molding shrinkage, and plays an important molding role in the system of the invention.
Nitrocellulose particles are a very common organic chemical, and under certain conditions, are dissolved in a solvent and co-solvent to form a slurry, and in this slurry, a certain proportion of reagents are added to adjust the properties of the final film, such reagents mainly comprising surfactants, high molecular polymers, shaping agents and the like are dissolved in a buffer system.
The NC film is smooth and flat in surface from appearance, free from foreign matters and impurities, and is selected to be suitable according to capillary flow time and protein binding capacity. The main factors affecting capillary flow time are membrane pore size, pore size distribution, membrane length, humidity, etc. The smaller the pore diameter, the slower the flow rate, the higher the sensitivity, and the longer the reaction time, the higher the probability of false positive generation, so that the more uniform the pore distribution, the more uniform the flow rate and the better the sensitivity at the same pore diameter. Further, in order to obtain an NC film with a better effect, the hydrotalcite added in the present invention is an exchangeable layered compound having a layered structure with anions carried between layers. The hydrotalcite spatial structure shows the insertionability and the interlayer carrying capacity of exchange of ions, so that functional polymer substances can enter interlayer pores of the hydrotalcite, the hydrotalcite is expanded but the space-removing structure cannot change greatly, meanwhile, the hydrophilic property of the membrane is greatly improved by adding the hydrotalcite, the pore size of the nitrocellulose membrane can be effectively controlled, and the detection performance of the NC membrane is improved.
The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.
Example 1
(1) Preparing a nitrocellulose membrane solution: pouring 0.02g of hydrotalcite, 20g of N, N-dimethylacetamide and 3g of nitrocellulose particles into a reaction device, stirring for more than 4 hours, adding 0.2g of acetone, 5g of polysulfone and 2g of polyvinylpyrrolidone, continuously stirring for 24-36 hours at the temperature of 60 ℃, and observing the content of solids in the reaction device until the solids are completely dissolved;
(2) Placing the prepared NC membrane liquid into a dry environment, standing for defoaming, wherein the process is to pay attention to foreign matter pollution, and the dry environment is kept clean;
(3) Before the film scraping process is started, the scraper glass plate is recommended to be cleaned by alcohol and then cleaned by deionized water for drying. Pouring NC film liquid onto a glass plate, scraping a film on the glass plate at a constant speed by using a scraper, and standing at room temperature for less than 1min;
(4) Standing the scraped glass plate in a gel water bath at a constant temperature of 35 ℃ for more than 1min
(5) Taking out the NC film falling off from the gel water bath, putting the NC film into deionized water, and standing;
(6) The NC film of deionized water was transferred to a vacuum oven at a drying temperature of 45 ℃.
Example 2
Example 2 preparation of nitrocellulose membrane solution step (1) is to pour 0.02g of hydrotalcite, 20g of N, N-dimethylacetamide and 3g of nitrocellulose particles into a reaction device and stir for more than 4 hours at room temperature, then add 0.2g of acetone, 5g of polysulfone and 2g of polyvinylpyrrolidone and continue stirring for 24-36 hours at 60 ℃, and observe the content of solid matters in the reaction device until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Example 3
In the preparation step (1) of the nitrocellulose membrane liquid in the example 3, 0.02g of hydrotalcite, 21g of N, N-dimethylacetamide and 4g of nitrocellulose particles are poured into a reaction device to be stirred for more than 4 hours, the process is carried out at room temperature, and then 0.3g of acetone, 6g of polysulfone and 3g of polyvinylpyrrolidone are added to be continuously stirred; the time is 24-36 h, the temperature is 60 ℃, the content of solid matters in the reaction device is observed, until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Example 4
Example 4 preparation of nitrocellulose membrane solution step (1) is that 0.08g of hydrotalcite, 21g of N, N-dimethylacetamide and 4g of nitrocellulose particles are poured into a reaction device to be stirred for more than 4 hours, the process is carried out at room temperature, and then 0.3g of acetone, 6g of polysulfone and 3g of polyvinylpyrrolidone are added to be continuously stirred; the time is 24-36 h, the temperature is 60 ℃, the content of solid matters in the reaction device is observed, until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Example 5
In the preparation step (1) of the nitrocellulose membrane liquid in the example 5, 0.08g of hydrotalcite, 20g of N, N-dimethylacetamide and 3g of nitrocellulose particles are poured into a reaction device to be stirred for more than 4 hours, the process is carried out at room temperature, and then 0.2g of acetone, 5g of polysulfone and 2g of polyvinylpyrrolidone are added to be continuously stirred; the time is 24-36 h, the temperature is 60 ℃, the content of solid matters in the reaction device is observed, until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Comparative example 1
In the preparation step (1) of the nitrocellulose membrane liquid in the comparative example 1, 20g of N, N-dimethylacetamide and 3g of nitrocellulose particles are poured into a reaction device to be stirred for more than 4 hours, the process is carried out at room temperature, and then 0.2g of acetone, 5g of polysulfone and 2g of polyvinylpyrrolidone are added to be continuously stirred; the time is 24-36 h, the temperature is 60 ℃, the content of solid matters in the reaction device is observed, until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Comparative example 2
In the preparation step (1) of the nitrocellulose membrane liquid in the comparative example 2, 0.1g of hydrotalcite, 20g of N, N-dimethylacetamide and 3g of nitrocellulose particles are poured into a reaction device to be stirred for more than 4 hours, the process is carried out at room temperature, and then 0.2g of acetone, 5g of polysulfone and 2g of polyvinylpyrrolidone are added to be continuously stirred; the time is 24-36 h, the temperature is 60 ℃, the content of solid matters in the reaction device is observed, until the solid matters are completely dissolved; the subsequent steps are the same as in (2) to (6) of example 1.
Table 1 comparative tables for performance tests of examples 1 to 5 and comparative examples 1, 2:
in the table, the test method and evaluation method of each performance are as follows:
1. hydrophilicity: the measurement was performed using a contact angle meter (SL 200B, solonetech.co., ltd.);
2. NC membrane pore size: the surface of NC film in the different examples was examined using scanning electron microscope model S4800 of HITACHI, japan for characterization.
From the detection result, the prepared NC membrane layer has good hydrophilicity with the thickness of 100 mu m as an example, the average pore diameter of the prepared NC membrane layer is 0.45 mu m, and the addition of hydrotalcite improves the porosity of the NC membrane supporting layer.
The NC films of examples 1-5 are prepared and added with different components, and the hydrophilia and pore size of the prepared NC films meet the requirements of the invention for solving the key technology, wherein the hydrotalcite is added with the mass of 0.02 g-0.08 g, and the NC films are smooth and clean in appearance and have no impurities, and meet the requirements for preparing NC films.
Comparative example 1 was compared with examples 1 to 5, and no hydrotalcite was added, resulting in NC films produced by the test, which were inferior in hydrophilicity and less in the number of apparent pore distribution, and did not meet the use requirements of NC films, compared with NC films produced in example 1.
In comparative example 2, compared with examples 1 to 5, hydrotalcite was added in an excessive amount, and the membrane pore size was satisfactory due to hydrophilicity, but the surface of the membrane had a crystalline substance generated, which affected the apparent quality of NC membrane.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (11)
1. The nitrocellulose membrane is prepared from nitrocellulose membrane solution, and is characterized by comprising the following raw materials in parts by weight:
20-21 parts of a solvent;
0.2-0.3 parts of cosolvent;
2-3 parts of a non-solvent;
5-6 parts of a forming agent;
0.02-0.08 parts of hydrotalcite;
3-4 parts of nitrocellulose particles,
the non-solvent comprises one or two of polyvinylpyrrolidone and cross-linked polyvinylpyrrolidone in any weight ratio.
2. A nitrocellulose membrane according to claim 1, wherein the solvent comprises one or two of N, N-dimethylformamide, N-dimethylacetamide in any weight ratio.
3. A nitrocellulose membrane according to claim 1, wherein the co-solvent comprises one or any weight ratio of acetone and butanone.
4. A nitrocellulose membrane according to claim 1, wherein the shaping agent comprises one or more of polysulphone, polyarylsulphone and polyethersulphone.
5. A method for producing a nitrocellulose membrane according to any one of claims 2 to 4, comprising the steps of:
step one, preparing a nitrocellulose membrane solution according to the proportioning of each substance;
step two, defoaming the nitrocellulose membrane solution in the step one to obtain nitrocellulose membrane casting solution;
scraping the film of the nitrocellulose film casting solution after the deaeration in the step two to form a film, and scraping the film on a clean toughened glass plate by using a scraper tool;
step four, shaping the nitrocellulose membrane formed by scraping the membrane in the step three, putting the nitrocellulose membrane into a gel bath with a fixed temperature, and performing gel bath treatment to obtain the shaped nitrocellulose membrane;
and fifthly, drying the shaped nitrocellulose membrane in the fourth step to obtain a nitrocellulose membrane finished product.
6. The method for preparing a nitrocellulose membrane according to claim 5, wherein in the step one nitrocellulose membrane solution, the stirring temperature is between 60 and 65 ℃ and the stirring time is more than 24 hours.
7. The method for preparing a nitrocellulose membrane according to claim 5, wherein the nitrocellulose membrane solution is required to be subjected to standing and deaeration for more than 24 hours.
8. The method for preparing a nitrocellulose membrane according to claim 5, wherein the gel bath ethanol content is 30% -40%, the temperature is 30% -35 ℃, and the time is more than 1min.
9. The method of claim 5, wherein the nitrocellulose membrane is released from the gel bath and allowed to stand in deionized water for a period of time greater than 4 hours.
10. The method for preparing a nitrocellulose membrane according to claim 9, wherein the nitrocellulose membrane which is kept in deionized water is taken out after being kept in a static state and dried at a temperature of 44 to 50 ℃.
11. The method for preparing a nitrocellulose membrane according to claim 6, wherein the preparation of the nitrocellulose membrane solution comprises the following steps:
step one, mixing a proportioning amount of the solvent and nitrocellulose particles with hydrotalcite, and then stirring at room temperature;
and secondly, adding the cosolvent, the forming agent and the non-solvent into the mixed solution, and continuously stirring at the temperature of 60-65 ℃ for 24-36 h.
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| CN103819710A (en) * | 2014-03-04 | 2014-05-28 | 苏州奥特福环境科技有限公司 | Method for preparing hydrophilic nitrated cellulose film |
| CN110218358A (en) * | 2019-05-31 | 2019-09-10 | 中南民族大学 | A kind of preparation method and its usage of cellulose/ZnAl hydrotalcite composite membrane |
| CN112094424A (en) * | 2020-08-26 | 2020-12-18 | 浙江美易膜科技有限公司 | Preparation method of nitrocellulose chromatographic membrane for rapid immunoassay, nitrocellulose chromatographic membrane and application thereof |
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| CN103819710A (en) * | 2014-03-04 | 2014-05-28 | 苏州奥特福环境科技有限公司 | Method for preparing hydrophilic nitrated cellulose film |
| CN110218358A (en) * | 2019-05-31 | 2019-09-10 | 中南民族大学 | A kind of preparation method and its usage of cellulose/ZnAl hydrotalcite composite membrane |
| CN112094424A (en) * | 2020-08-26 | 2020-12-18 | 浙江美易膜科技有限公司 | Preparation method of nitrocellulose chromatographic membrane for rapid immunoassay, nitrocellulose chromatographic membrane and application thereof |
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