Microorganism-enriched filter element as well as preparation method and device thereof

Abstract

The invention discloses a filter element for enriching microorganisms and a preparation method and device thereof, according to the filter element for enriching microorganisms, the interior of a core body of the filter element is provided with a pore structure, the pore diameter of the pore structure is 0.5-50 microns, and the filter element is used for filtering to-be-enriched microorganism sample liquid for enrichment. According to the filter element, microorganisms can be efficiently enriched, and the influence on the activity of the microorganisms or subsequent detection and analysis is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of microorganism enrichment, and in particular to a filter element for enriching microorganisms and a preparation method and device thereof. Background Art

[0002] Microbial enrichment is a key starting point in the modern biotechnology process. Through enrichment, original samples with low microbial concentrations can be converted into samples with higher microbial concentrations to better meet subsequent testing or analysis needs.

[0003] At present, microbial enrichment methods include centrifugation, filtration, adsorption and chemical precipitation. Centrifugation relies on centrifuge equipment, and the strong shear force generated by high-speed rotation may destroy the microbial cell structure, causing the microbial activity to weaken or even lose, thereby affecting subsequent culture and identification. The filtration method is generally based on microfiltration membranes, ultrafiltration membranes, etc., but the filtration time is long, and the filter membrane is easily blocked by impurities, requiring frequent replacement, interrupting the operation process, reducing the overall efficiency, and the ability of the filter membrane to be reused is limited, and the cost is relatively high. The adsorption method is complicated because the regeneration of the adsorption material is more cumbersome, which affects the repeated use of the adsorption material. The chemical precipitation method uses various chemical reagents to induce microbial aggregation and precipitation. The subsequent cleaning process is complicated and it is difficult to completely remove the residual reagents. These impurities are mixed into the sample, which may interfere with the normal physiological state of the microorganism, and may affect the subsequent culture and analysis.

[0004] Therefore, there is an urgent need for a microbial enrichment method that can not only efficiently enrich microorganisms, but also reduce the impact on microbial activity and is easy to operate. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art and effectively solve the problems of low efficiency and influence on microbial activity of the prior art microbial enrichment methods, the present application provides a filter element for enriching microorganisms and its preparation method and application. The present application adopts the following technical solutions:

[0006] The first aspect of the present application discloses a filter element for enriching microorganisms, wherein the core of the filter element has a porous structure, the pore size of the porous structure is 0.5μm to 50μm, and the filter element is used to filter the microbial sample liquid to be enriched for enrichment. It should be noted that the present application uses a filter element with a porous structure for microbial enrichment, the pore size of the porous structure is 0.5μm to 50μm, and it can intercept microorganisms of different sizes, such as bacteria, fungi, spores, etc. The filter element of the present application does not require high-speed centrifugal rotation or the use of chemical precipitants during the enrichment process. Compared with sheet-like filter membranes, it has good permeability, can efficiently enrich microorganisms, and reduce the impact on microbial activity or subsequent detection and analysis.

[0007] In one implementation of the present application, the material of the filter element includes at least one of the following polymers: polyethylene, polypropylene, polystyrene, and polyvinyl chloride. It should be noted that the polyethylene (PE) material has good chemical stability and is resistant to acid and alkali corrosion. The filter element prepared can adapt to a variety of complex sample environments, from acidic industrial wastewater to alkaline soil extract lamps; secondly, the electrostatic charge carried on the surface of the polyethylene material can attract the surface charge of the microorganism, prompting the microorganism to approach the surface of the filter element; the polyethylene material also has a certain oleophobicity, and the oily pollutants in the microbial sample liquid to be enriched are difficult to adhere to the filter element, thereby reducing the interference of impurities and ensuring the purity of the enriched sample.

[0008] In one implementation of the present application, the polymer is polyethylene.

[0009] In one implementation of the present application, the core is a core having a porous structure obtained by sintering particles of the polymer.

[0010] In one implementation of the present application, the pore size of the pore structure gradually decreases along the filtering direction. It should be noted that the pore size of the pore structure in the filter element gradually decreases, which can be beneficial to achieve graded enrichment and improve enrichment efficiency.

[0011] In one implementation of the present application, the filter element comprises a plurality of core bodies, and along the filtering direction, the pore sizes of the pore structures of the plurality of core bodies decrease sequentially. It should be noted that a whole filter element can be obtained by combining a plurality of core bodies with pore structures of different pore sizes.

[0012] In one implementation of the present application, the multiple cores are arranged in sequence along the filtering direction.

[0013] In one implementation of the present application, the multiple cores are integrally formed.

[0014] In one implementation of the present application, the pore structure has a pore size of 0.5 μm to 30 μm.

[0015] In one implementation of the present application, a hydrophilic substance is attached to the surface of the pore structure. It should be noted that by attaching a hydrophilic substance to the surface of the pore structure, the adsorption affinity of the pore structure to microorganisms can be enhanced, making it easier for microorganisms to attach and improving the enrichment efficiency.

[0016] In one implementation of the present application, the surface of the pore structure has a hydrophilic membrane layer composed of the hydrophilic substance.

[0017] In one implementation of the present application, the hydrophilic substance includes a surfactant.

[0018] In one implementation of the present application, the surfactant includes at least one of the following: Tween, sodium dodecyl sulfate. It should be noted that Tween is a nonionic surfactant mainly composed of polyoxyethylene chains and fatty acid esters. Due to the characteristics of its molecular structure, Tween has good hydrophilicity and certain oleophobicity, and typical representatives include Tween 20, Tween 40, Tween 60, and Tween 80.

[0019] The second aspect of the present application discloses a method for preparing a filter element for enriching microorganisms, comprising: filling filter element substrate particles with a particle size of 3μm to 100μm into a mold, performing a temperature increase procedure, and sintering to obtain the filter element with a pore structure. It should be noted that the formation principle of the pore structure can be understood as follows: since the filter element substrate particles are discretely distributed before sintering, there are gaps between the particles, which gradually melt under the temperature increase procedure, and the particles partially fuse, thereby gradually building a three-dimensional interconnected pore structure; in addition, during the sintering process, the particle contact points will preferentially soften and form a "sintering neck", and the growth rate of the sintering neck is limited, especially under low-temperature sintering conditions, resulting in the inability to completely eliminate the gaps between the particles; in addition, during the sintering process, some gas may exist to form pores. By using filter element substrate particles of suitable particle size for sintering, a filter element with a pore structure of 0.5 to 50μm can be obtained. This multi-scale pore design can adapt to microorganisms of different sizes, from common bacteria to fungal spores, which can be effectively intercepted.

[0020] In one implementation of the present application, the material of the filter element substrate particles includes at least one of the following polymers: polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0021] In one implementation of the present application, the sintering temperature is not higher than the melting temperature of the polymer. It should be noted that, as a result, the particles will not be completely melted, but will be partially fused through mechanisms such as surface diffusion and viscous flow, thereby forming a porous structure.

[0022] In one implementation of the present application, the filter element substrate is polyethylene, and the heating procedure is: heating to 120°C to 140°C at a rate of 5°C to 10°C and then maintaining for 2 hours to 3 hours. It should be noted that the sintering temperature and sintering time are related to the porosity and pore size of the pore structure. For example, if the sintering temperature is high or the sintering time is long, more particles may melt and form fewer pores.

[0023] In one implementation of the present application, the temperature increase procedure further includes applying a pressure of 5 MPa to 10 MPa. It should be noted that applying appropriate pressure can promote the full melting and bonding of the filter substrate core particles, and sintering to form a stable filter element matrix.

[0024] In one implementation of the present application, the filter element substrate particles are divided into large particles and small particles according to their particle size, wherein the particle size of the large particles is 50 to 100 μm, and the particle size of the small particles is 3 to 50 μm.

[0025] In one implementation of the present application, the preparation method includes: sequentially filling the large particles and the small particles into the mold, performing the temperature increase procedure, and sintering to obtain the filter element.

[0026] In one implementation of the present application, the large particles, the mixture of the large particles and the small particles, and the small particles are sequentially filled into the mold, and the temperature rise procedure is performed to sinter the filter element.

[0027] In one implementation of the present application, after the temperature rising procedure, a hydrophilization treatment is further included, and the hydrophilization treatment includes: making a hydrophilic substance adhere to the surface of the pore structure.

[0028] In one implementation of the present application, the hydrophilization treatment includes: forming a hydrophilic film layer composed of the hydrophilic substance on the surface of the pore structure.

[0029] In one implementation of the present application, the hydrophilic treatment includes: dissolving the hydrophilic substance in ethanol to obtain a hydrophilic substance solution, immersing the filter element in the hydrophilic substance solution at 50°C to 80°C for 20min to 60min, and using ultrasonic treatment during the immersion process. It should be noted that since polyethylene is hydrophobic, the hydrophilic substance is dissolved in ethanol instead of water, so that the hydrophilic substance can enter the pore structure and adhere to the surface of the pore structure; the role of ultrasound is to eliminate bubbles in the pore structure, further ensuring the effect of the hydrophilic treatment.

[0030] In one implementation of the present application, the hydrophilization treatment includes: forming a hydrophilic film layer composed of the hydrophilic substance on the surface of the porous structure by a vapor deposition method.

[0031] In one implementation of the present application, the hydrophilic substance includes at least one of the following: Tween and sodium dodecyl sulfate.

[0032] The third aspect of the present application discloses a device for enriching microorganisms, which includes a filter element as disclosed in the first aspect of the present application, and an inlet and an outlet connected to the filter element. The microbial sample liquid to be enriched enters the filter element through the inlet, and the remaining filtrate flows out from the outlet.

[0033] The beneficial effects of this application are:

[0034] In the present application, a filter element with a porous structure is used for microbial enrichment. The pore size of the porous structure is 0.5 μm to 50 μm, which can intercept microorganisms of different sizes, such as bacteria, fungi, spores, etc. The filter element of the present application does not require high-speed centrifugal rotation or the use of chemical precipitants during the enrichment process. Compared with the filter membrane, it has good permeability, can efficiently enrich microorganisms, and reduce the impact on microbial activity or subsequent detection and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural diagram of the device for enriching microorganisms involved in the present application. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other materials and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and the related operations can be fully understood according to the description in the specification and the general technical knowledge in the art.

[0037] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0038] Microbial enrichment is the key starting point of modern biotechnology processes. Traditional microbial enrichment methods have significant defects: the centrifugation method relies on centrifuge equipment. When processing large-volume samples, not only does the equipment take a long time to operate, but the strong shear force generated by high-speed rotation will destroy the microbial cell structure, causing the microbial activity to be lost, affecting subsequent cultivation and identification work; although membrane filtration is relatively simple to operate, the membrane is easily clogged by impurities and needs to be replaced frequently, which not only increases costs, but also interrupts the operation process and reduces overall efficiency; the chemical precipitation method uses various chemical reagents to induce microbial aggregation and precipitation. The subsequent complicated cleaning process is difficult to completely remove residual reagents. These impurities are mixed into the sample, interfering with the normal physiological state of the microorganism, and will also cause deviations in accurate detection. Therefore, the industry urgently needs a new technology that can not only efficiently enrich microorganisms, but also maintain microbial activity, is easy to operate, and has controllable costs.

[0039] In view of this, the present application creatively proposes a PE (polyethylene) sintered filter element. PE as a raw material has excellent chemical stability, acid and alkali corrosion resistance, and can adapt to a variety of complex sample environments, from acidic industrial wastewater to alkaline soil extracts. Under the high-temperature sintering process, PE particles are melted and bonded, and a three-dimensional interconnected pore structure is gradually constructed. The pore size is precisely controlled in the range of 0.5 to 50 μm. This multi-scale pore size design can adapt to microorganisms of different sizes, from common bacteria to fungal spores, which can be effectively intercepted. During the enrichment process, the sample containing microorganisms is introduced into a filtration system equipped with a PE sintered filter element. When the sample flows through the filter element, the microorganisms are retained by multiple physical and chemical effects. The first is size screening, the adaptation of the pore size to the particle size of the microorganism directly blocks the passage of the microorganism; the second is electrostatic adsorption, the electrostatic charge carried on the surface of the PE material and the surface charge of the microorganism attract each other, prompting the microorganism to approach the surface of the filter element; the third is the surface tension effect, which allows the microorganism to be firmly attached to the pores. Thanks to the unique sintering structure, the filter element has high permeability, allowing the sample to maintain a faster flow rate. The pore size distribution of the filter element gradually becomes smaller, achieving graded enrichment and improving enrichment efficiency. Unlike traditional plugging filtration, the rapid liquid flow reduces the residence time of microorganisms in unsuitable environments, minimizing the risk of microbial metabolic damage caused by factors such as accumulation of metabolic substrates and insufficient dissolved oxygen. The entire process operates at normal temperature and pressure (or low pressure), greatly preserving the activity of microorganisms.

[0040] In addition, the hydrophilic treatment of the filter surface can significantly enhance the adsorption affinity for microorganisms. With the help of hydrophilic treatment, microorganisms are easier to attach without changing the essential properties of PE materials. At the same time, the filter element also has oleophobic properties, making it difficult for oily pollutants to adhere, reducing impurity interference and ensuring the purity of the enriched sample.

[0041] The present application relates to a filter element for enriching microorganisms, a method for preparing the filter element for enriching microorganisms, a device for enriching microorganisms, and a method for enriching microorganisms.

[0042] In a specific embodiment, the filter element is used to filter a microbial sample solution to be enriched for enrichment.

[0043] In a specific embodiment, the microbial sample liquid to be enriched may include, but is not limited to, sewage, soil extract, tissue lavage liquid, and biological fermentation liquid.

[0044] In a specific embodiment, the core of the filter element has a porous structure inside.

[0045] In a specific embodiment, the pore structure has a pore size of 0.5 μm to 50 μm. For example, the pore structure may have a pore size of 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0046] In a specific embodiment, the pore size of the pore structure is 0.5 μm to 30 μm.

[0047] In a specific embodiment, the filter element may be in block form. It should be noted that block refers to solid materials with a certain volume and three-dimensional size, rather than other forms such as powder, particles, film or fiber. Compared with sheet (film) filter membranes, the block filter element has a longer pore structure distribution length and is not easy to form blockage.

[0048] In a specific embodiment, the outer shape of the filter element can be a cylinder, a cube, a cuboid, etc.

[0049] In a specific embodiment, the filter element can be a cylinder with a radius of 2 mm to 15 mm and a height of 10 mm to 50 mm. The microbial sample liquid to be enriched enters from one bottom surface of the cylinder, and the remaining filtrate flows out from the other bottom surface of the cylinder. In other words, the height direction of the cylinder is parallel to the filtering direction of the microbial sample liquid to be enriched.

[0050] In a specific embodiment, the material of the filter element includes at least one of the following polymers: polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0051] In a specific embodiment, the filter element can be obtained by sintering polymer particles. The polymer particles can be spherical and / or quasi-spherical.

[0052] In a specific embodiment, the material of the filter element may include polyethylene.

[0053] In a specific embodiment, the molecular weight of the polyethylene may be 50,000 to 5,000,000 Daltons.

[0054] In one embodiment, the polyethylene is ultra high molecular weight polyethylene (UHMWPE) having a molecular weight of 3 to 6 million Daltons.

[0055] In a specific embodiment, the filter element can be obtained by sintering polyethylene particles.

[0056] In a specific embodiment, the polyethylene particles may be spherical and / or spherical in shape.

[0057] In a specific embodiment, the particle size of the polymer particles can be 3 to 100 μm. For example, the particle size of the polymer particles can be 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm / 95 μm or 100 μm. It should be noted that the particle size here can refer to an equivalent particle size, for example, a volume equivalent particle size, an area equivalent particle size. Preferably, the particle size of the polymer particles can be 5 to 80 μm.

[0058] In a specific embodiment, in the filter element, the pore size of the pore structure gradually decreases along the filtering direction.

[0059] In a specific embodiment, the filter element includes a plurality of cores, and the pore sizes of the pore structures of the plurality of cores decrease in sequence along the filtering direction. For example, along the filtering direction, the filter element includes a first core, a second core, and a third core, and the pore size (which may refer to the average pore size) of the pore structure in the first core is larger than the pore size of the pore structure in the second core, and the pore size of the pore structure in the second core is larger than the pore size of the pore structure in the third core.

[0060] In a specific embodiment, a plurality of cores are arranged in sequence along the filtering direction.

[0061] In a specific embodiment, the plurality of cores are integrally formed.

[0062] In a specific embodiment, a hydrophilic substance is attached to the surface of the porous structure.

[0063] In a specific embodiment, the surface of the porous structure has a hydrophilic film layer composed of the hydrophilic substance.

[0064] In one embodiment, the hydrophilic substance includes a surfactant.

[0065] In a specific embodiment, the surfactant includes at least one of the following: Tween, sodium dodecyl sulfate (K12). For example, it may include at least one of Tween 20, Tween 40, Tween 60, and Tween 80.

[0066] In a specific embodiment, a method for preparing a filter element for enriching microorganisms may include: filling filter element substrate particles into a mold, performing a temperature increase procedure, and sintering to obtain a filter element with a porous structure.

[0067] In a specific embodiment, the shape of the mold can be customized according to the shape of the filter element.

[0068] In a specific embodiment, the filter element substrate particles may be polymer particles. The description of the polymer particles can refer to the above content and will not be repeated here.

[0069] In a specific embodiment, the sintering temperature may be no higher than the melting temperature of the polymer. For example, the sintering temperature may be the melting temperature ±15°C.

[0070] In a specific embodiment, the sintering temperature may be 120°C to 160°C.

[0071] In a specific embodiment, the sintering time is 1 h to 4 h.

[0072] In a specific embodiment, the filter element substrate particles are polyethylene particles, and the heating procedure is: heating to 120°C to 140°C at a rate of 5°C to 10°C and then maintaining for 2 hours to 3 hours.

[0073] In a specific embodiment, the temperature raising procedure further includes applying a pressure of 5 MPa to 10 MPa.

[0074] In a specific embodiment, the preparation method of the filter element for enriching microorganisms may include: classifying the filter element substrate according to the particle size range, and sequentially loading the particle size range from large to small into the mold for sintering. For example, the filter element substrate particles with a particle size of 80 to 100 μm, the filter element substrate particles with a particle size of 30 to 80 μm, and the filter element substrate particles with a particle size of 3 to 30 μm can be divided into the mold in sequence according to the particle size, and the temperature is raised to sinter to obtain a filter element with a porous structure. Among them, the mass ratio of the added particles of different particle size ranges can be 0.5 to 1.5: 0.5 to 1.5: 0.5 to 1.5. For example, the mass ratio of the filter element substrate particles with a particle size of 80 to 100 μm, the filter element substrate particles with a particle size of 30 to 80 μm, and the filter element substrate particles with a particle size of 3 to 30 μm can be 1:1:1.

[0075] In a specific embodiment, the method for preparing a filter element for enriching microorganisms further includes a hydrophilization treatment after the temperature raising procedure.

[0076] In a specific embodiment, the hydrophilization treatment includes: attaching a hydrophilic substance to the surface of the pore structure. The description of the hydrophilic substance can refer to the above content and will not be repeated here.

[0077] In a specific embodiment, the hydrophilization treatment includes: forming a hydrophilic film layer composed of a hydrophilic substance on the surface of the porous structure.

[0078] In a specific embodiment, the hydrophilization treatment includes: dissolving the hydrophilic substance in ethanol to obtain a hydrophilic substance solution, soaking the filter element in the hydrophilic substance solution at 50° C. to 80° C. for 20 min to 60 min, and performing ultrasonic treatment during the soaking process. The frequency of the ultrasonic treatment can be 20 to 100 kHz.

[0079] In a specific embodiment, the hydrophilization treatment includes: forming a hydrophilic film layer composed of a hydrophilic substance on the surface of the porous structure by a vapor deposition method.

[0080] In a specific embodiment, the vapor deposition method may include: (1) Precursor selection: using a gaseous precursor containing a hydrophilic group (such as a hydroxyl group or an amino group), such as a derivative of polyethyleneimine (PEI) or polyacrylic acid (PAA), or generating a hydrophilic coating through a hydrolysis reaction. (2) Pulse injection: alternately injecting two precursors (such as a hydrophobic precursor containing silane and a hydrophilic monomer), and reducing parasitic reactions through a phase-shifted pulse sequence. (3) Parameter control: the deposition chamber pressure is >500mTorr, the temperature is controlled at 80-100°C, and the pulse interval is greater than the pulse duration to ensure that the reaction occurs preferentially on the substrate surface. Reaction process: The precursor adsorbs, reacts and forms a cross-linked hydrophilic coating on the substrate surface, such as improving hydrophilicity and stability through co-deposition of PEI and dopamine.

[0081] In one specific embodiment, the device for enriching microorganisms comprises the filter element as described above.

[0082] In a specific embodiment, the device for enriching microorganisms further includes an inlet and an outlet connected to the filter element, the microorganism sample liquid to be enriched enters the filter element through the inlet, and the remaining filtrate flows out from the outlet.

[0083] In a specific embodiment, the method for enriching microorganisms may include: a filtration step: passing the microorganism sample liquid to be enriched through a filter element so that the microorganisms are retained in the filter element; an elution step: using an elution liquid to elute the microorganisms retained in the filter element into the elution liquid to obtain an enriched microorganism sample.

[0084] In a specific embodiment, the microorganisms are retained in the pore structure of the filter element by at least one of physical interception, electrostatic adsorption, and surface tension.

[0085] In one specific embodiment, the filtering step is performed at room temperature.

[0086] In one embodiment, the filtering step is performed under normal pressure.

[0087] In a specific embodiment, the filtering step is performed under negative pressure, and the negative pressure may be -5Kpa to -60Kpa.

[0088] In a specific embodiment, the filter element has good permeability, which can allow the sample to maintain a faster flow rate (under the condition of gravity flow, the flow rate of water can be 5-50 mL / min).

[0089] In a specific embodiment, during the elution step, vortexing or shaking can be performed to elute the microorganisms retained in the filter element into the elution solution.

[0090] In a specific embodiment, the volume of the eluent may be 1 to 10 times the volume of the filter element. For example, the volume of the eluent may be 1 to 3 times the volume of the filter element.

[0091] In a specific embodiment, the eluent may be a phosphate buffer, which is helpful for maintaining the activity of the microorganisms.

[0092] In a specific embodiment, a device 100 for enriching microorganisms is also provided. Figure 1 is a structural diagram of a device 100 for enriching microorganisms involved in the present application, such as Figure 1 As shown, the device 100 includes a filter element 30, and an inlet 10 and an outlet 20 connected to the filter element 30. The microbial sample liquid to be enriched enters the filter element 30 through the inlet 10, and the remaining filtrate flows out from the outlet 20, and the filtering direction is shown as D.

[0093] The present application is further described in detail below by specific examples and comparative examples. The following examples are only further described herein and should not be construed as limiting the present application. In the present embodiment, unless otherwise specified, the reagents and instruments used are all commercially available, and the experimental operations are performed in accordance with the product instructions and conventional experimental specifications.

[0094] Example:

[0095] Material preparation: Select food-grade PE particles with a molecular weight of 3 million Da and an impurity content of less than 0.1%. Classify PE particles with a particle size range of 50 to 100 as large-size particles, and PE particles with a particle size range of 3 to 50 as small-size particles. Spread the particles flat in a vacuum drying oven tray, set the temperature to 80°C, and dry for 4 hours to remove moisture and residual volatile impurities.

[0096] Sintering molding: Carefully fill the dried PE particles into a custom mold. The mold is a cylinder with a radius of 4mm and a height of 40mm. The filling process is divided into three steps. First, fill in small-size particles, then fill in large-size and small-size mixed particles, and finally fill in large-size particles. The particles used in the three parts have the same content. Start the heating program, heat up to 130℃ at a rate of 5℃ per minute, and keep warm for 2.5 hours. During this period, apply 5MPa pressure to promote the full melting and adhesion of PE particles to form a stable filter element matrix. Then naturally cool and demould to obtain the initial filter element.

[0097] Hydrophilization treatment: Prepare 5% Tween 20 ethanol solution, completely immerse the demoulding initial filter element in the solution, put it into an ultrasonic cleaning machine, and perform ultrasonic treatment for 30 minutes at 60°C and an ultrasonic frequency of 40kHz. After the treatment, take it out and dry it in a sterile ventilated environment for later use.

[0098] Microbial enrichment:

[0099] 1) Assembly The filter elements prepared in the examples are installed in the polished and passivated stainless steel filter cylinders, and silicone sealing rings are placed at the contact points between the two ends of the filter element and the cylinder wall to ensure that the sealing interface is leak-free. A silicone hose with good flexibility is connected as the sample inlet and sample outlet. After the assembly is completed, the entire device is rinsed 3 times with sterile water at a flow rate of 50 ml / min in advance to remove possible residual impurities.

[0100] 2) Filtration: The microbial sample to be enriched is a suspension of Escherichia coli (concentration 10 5 CFU / mL), take 200ml of bacterial suspension and slowly pour it into the inlet. Under a pressure of -20Kpa, let the sample flow through the filter element. The filtration is completed when no liquid flows out of the outlet. Record the filtration time (i.e. the time required for enrichment).

[0101] 3) Microbial collection: After filtration, gently remove the filter element and place it in a centrifuge tube containing 50 mL of sterile phosphate buffer. Vortex and shake for 5 minutes to allow the enriched microorganisms to be fully eluted into the buffer. The resulting microbial suspension is the enriched microbial sample.

[0102] 4) Detection of microbial enrichment results

[0103] The enriched microbial samples were tested for microbial content and activity. The microbial content was tested by turbidimetry, and the microbial activity was tested by MTT colorimetry.

[0104] Comparative Example: The comparative example uses a microporous filter membrane for filtration, the pore size of the filter membrane is 0.22 μm, the diameter is 47 mm, and the material is PES. The microbial enrichment operation is the same as that of the embodiment, and the bacterial suspension is also filtered at a pressure of -20 KPa to achieve microbial enrichment.

[0105] The results are shown in the table below:

[0106] Group Enrichment time Microbial enrichment multiple Microbial activity retention rate Example 5min 20 times 99％ Comparative Example 30min 40 times 87％

[0107] The above contents are further detailed descriptions of the present application in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application.

Claims

1. A filter element for enriching microorganisms, characterized in that: The core of the filter element has a pore structure inside, the pore size of the pore structure is 0.5 μm to 50 μm, and the filter element is used to filter the microbial sample liquid to be enriched for enrichment.

2. The filter element according to claim 1, characterized in that: The material of the filter element includes at least one of the following polymers: polyethylene, polypropylene, polystyrene, polyvinyl chloride; Preferably, the polymer is polyethylene; Preferably, the core is a core having a porous structure obtained by sintering particles of the polymer.

3. The filter element according to claim 1, characterized in that: Along the filtering direction, the pore size of the pore structure gradually decreases; Preferably, the filter element comprises a plurality of core bodies, and along the filtering direction, the pore sizes of the pore structures of the plurality of core bodies decrease sequentially; Preferably, the plurality of cores are arranged in sequence along the filtering direction; Preferably, the plurality of cores are integrally formed; The pore structure has a pore diameter of 0.5 μm to 30 μm.

4. The filter element according to any one of claims 1 to 3, characterized in that: A hydrophilic substance is attached to the surface of the pore structure; Preferably, the surface of the pore structure has a hydrophilic film layer composed of the hydrophilic substance.

5. The filter element according to claim 4, characterized in that: The hydrophilic substance includes a surfactant; Preferably, the surfactant comprises at least one of the following: Tween, sodium dodecyl sulfate.

6. A method for preparing a filter element for enriching microorganisms, characterized in that: include: Fill filter element substrate particles with a particle size of 3 μm to 100 μm into a mold, perform a temperature increase procedure, and sinter to obtain the filter element with a porous structure.

7. The preparation method according to claim 6, characterized in that: The material of the filter element substrate particles includes at least one of the following polymers: polyethylene, polypropylene, polystyrene, polyvinyl chloride; Preferably, the sintering temperature is not higher than the melting temperature of the polymer; Preferably, the filter element substrate is polyethylene, and the heating procedure is: heating to 120°C to 140°C at a rate of 5°C to 10°C and then maintaining for 2 hours to 3 hours; Preferably, the temperature rising procedure further comprises applying a pressure of 5 MPa to 10 MPa.

8. The preparation method according to claim 6, characterized in that: include: The filter element substrate particles are divided into large particles and small particles according to the particle size, wherein the particle size of the large particles is 50 to 100 μm, and the particle size of the small particles is 3 to 50 μm; Preferably, the preparation method comprises: sequentially filling the large particles and the small particles into the mold, performing the temperature increase procedure, and sintering to obtain the filter element; Preferably, the preparation method comprises: sequentially filling the large particles, a mixture of the large particles and the small particles, and the small particles into the mold, performing the temperature increase procedure, and sintering to obtain the filter element.

9. The preparation method according to any one of claims 6 to 8, characterized in that: After the temperature rising procedure, a hydrophilization treatment is also included, and the hydrophilization treatment includes: making a hydrophilic substance adhere to the surface of the pore structure; Preferably, the hydrophilization treatment comprises: forming a hydrophilic film layer composed of the hydrophilic substance on the surface of the pore structure; Preferably, the hydrophilization treatment comprises: dissolving the hydrophilic substance in ethanol to obtain a hydrophilic substance solution, soaking the filter element in the hydrophilic substance solution at 50° C. to 80° C. for 20 min to 60 min, and using ultrasonic treatment during the soaking process; Preferably, the hydrophilization treatment comprises: forming a hydrophilic film layer composed of the hydrophilic substance on the surface of the pore structure by a vapor deposition method; Preferably, the hydrophilic substance comprises at least one of the following: Tween and sodium dodecyl sulfate.

10. A device for enriching microorganisms, characterized in that: The device comprises a filter element as claimed in any one of claims 1 to 5, and an inlet and an outlet connected to the filter element, the microbial sample liquid to be enriched enters the filter element through the inlet, and the remaining filtrate flows out from the outlet.

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