Janus air filter membrane for integrated bioaerosol capture, detection, and disinfection, and its preparation method.

Abstract

This invention discloses a Janus air filter membrane for integrated capture, detection, and disinfection of bioaerosols and its preparation method, belonging to the field of filter membrane technology. The technical solution is as follows: the air filter membrane has an asymmetric two-sided structure and a soluble micro / nanoporous network structure. It is formed by asymmetric modification of the filter membrane surface with an amphiphilic AIE photosensitizer. The Janus structure is constructed without damaging the overall structure of the filter membrane, achieving the aggregation of the AIE photosensitizer on one side of the filter membrane. The air filter membrane possesses both green capture and detection performance and AIE photodynamic disinfection performance. The preparation method includes solution preparation, filter membrane forming, surface asymmetric modification, and drying. The Janus air filter membrane of this invention can not only achieve efficient capture and enrichment of bioaerosols and, after staining, be used for microbial detection guided by near-infrared fluorescence imaging, but also effectively inactivate airborne pathogens with the aid of white light irradiation.

Description

Technical Field

[0001] This invention belongs to the field of filter membrane technology, specifically relating to a Janus air filter membrane for integrated capture, detection, and disinfection of bioaerosols and its preparation method. Background Technology

[0002] Bioaerosols contain a variety of microorganisms, such as bacteria, fungi, viruses, spores, and archaea. Due to their light weight and small particle size, they can not only remain suspended in the air for extended periods but also travel long distances with airflow. Pathogens originating from human activities and natural processes can also diffuse into the air, combine with bioaerosols, and spread rapidly, causing serious airborne microbial pollution events. Bioaerosol transmission has been proven to be one of the main routes of transmission for some infectious diseases. Exposure to and inhalation of infectious pathogens from bioaerosols can harm human health and may even induce fatal diseases. Therefore, efforts have been made to develop advanced bioaerosol capture and inactivation strategies to control airborne microbial pollution and improve air quality. However, indiscriminate disinfection cannot achieve the source tracing and eradication of airborne microbial pollution; instead, it leads to severe energy waste due to excessive disinfection. To gain a deeper understanding of the actual situation of bioaerosols and prevent environmental safety incidents caused by airborne microbial pollution, the collection and detection of airborne pathogens has been identified as a key prerequisite for real-time sensitive monitoring and targeted inactivation of bioaerosols. Furthermore, precise bioaerosol detection technology can provide timely early warnings, early predictions, and risk assessments for the prevention and control of aerosol-borne diseases. In general, the prevention and control of airborne microbial pollution is a dynamic process. The complexity, variability, and spatiotemporal diversity of airborne pathogens require a comprehensive understanding of their capture, detection, and inactivation processes, necessitating the development of intelligent prevention and control strategies that combine offense and defense.

[0003] Air filtration is one of the most commonly used air purification methods, playing a crucial role in controlling the spread of bioaerosols and protecting human health. Through diffusion, sieving, and interception, porous filter media can effectively intercept and capture airborne microbial particles. Filtration methods have gained significant attention due to their ease of operation, durability, high collection efficiency, and low cost. By introducing bactericides or constructing destructive nanostructures into air filter materials, filtration-based disinfection can effectively retain airborne microorganisms and achieve broad-spectrum antibacterial activity, effectively controlling the spread of bioaerosols and reducing the risk of secondary pollution. While this passive filtration-capture, removal, and disinfection mode plays a vital role in blocking the spread of pathogenic aerosols, this filtration sampling method is not ideal for accurate detection of bioaerosols. Soluble filter membrane materials prepared through a dual green screening model of raw materials and preparation processes can effectively overcome these problems. They not only ensure the green capture and enrichment of airborne pathogens but also eliminate the need for extraction and elution steps, easily achieving maximum sample transfer after bioaerosol sampling, thus enabling rapid quantitative detection of airborne pathogens captured by filtration. Among these, efficient airborne microbial capture and non-invasive transfer methods provide a rapid and accurate detection approach for real-time monitoring of bioaerosols. However, the lack of necessary sterilization methods limits this approach to bioaerosol capture and detection, failing to achieve the goal of actively controlling microbial contamination. Faced with complex airborne microbial contamination problems, rapid detection and timely disinfection of bioaerosols are essential means to combat airborne pathogens; neither can be dispensed with. However, currently reported air filtration technologies typically only achieve a single detection or disinfection mode after bioaerosol sampling, falling far short of the goal of intelligent control of bioaerosols. Therefore, there is an urgent need to develop an all-around filter material capable of simultaneously capturing, detecting, and disinfecting bioaerosols to achieve intelligent control of airborne microbial contamination. Summary of the Invention

[0004] This invention provides a Janus air filter membrane for integrated bioaerosol capture, detection, and disinfection, and its preparation method, aiming to overcome the limitations of traditional single bioaerosol detection and disinfection modes, and to provide a new method for intelligent control of airborne microbial pollution. The Janus air filter membrane described in this invention can not only achieve efficient capture and enrichment of bioaerosols, and after staining, be used for microbial detection guided by near-infrared fluorescence imaging, but also effectively inactivate airborne pathogens with the aid of white light irradiation.

[0005] The technical solution of this invention is as follows:

[0006] In the first aspect, a Janus air filter membrane for integrated bioaerosol capture, detection, and disinfection is disclosed. The air filter membrane has an asymmetric two-sided structure and a soluble porous network structure. It is formed by asymmetric modification of the filter membrane surface with an amphiphilic AIE photosensitizer. The Janus structure is constructed without destroying the overall structure of the filter membrane, thereby achieving the aggregation of the AIE photosensitizer on one side of the filter membrane. The air filter membrane has green capture and detection performance and photodynamic disinfection performance. It can not only effectively overcome the aggregation-induced quenching (ACQ) effect and generate strong fluorescence emission for microbial imaging, but also has a high reactive oxygen generation capacity for efficient sterilization under light control.

[0007] Preferably, the AIE photosensitizer introduced into the air filter membrane has a broad-spectrum microbial transfection capability, effectively staining both Gram-positive and Gram-negative bacteria, and enabling visual detection of captured microorganisms under near-infrared fluorescence imaging guidance.

[0008] Preferably, the asymmetrical two-sided structure includes a capture surface and an AIE photosensitive surface, and the capture, detection and elimination of microbial aerosols are achieved by selecting the capture surface and the AIE photosensitive surface.

[0009] Preferably, the AIE photosensitizer is an amphiphilic molecule that is soluble in organic solvents for asymmetric modification of the filter membrane surface, and is also soluble in water. There should be a strong interaction between the porous network structure of the filter membrane and the AIE photosensitizer to ensure that the photosensitizer can be firmly modified on the surface of the filter membrane.

[0010] Preferably, the structural formula of the AIE photosensitizer is:

[0011] .

[0012] Secondly, a method for preparing the Janus air filter membrane for integrated bioaerosol capture, detection, and disinfection is disclosed, comprising the following steps:

[0013] 1) Dissolve the biomass material in water, heat and stir, add solvent until completely dissolved, and obtain a stable membrane solution;

[0014] 2) The membrane solution is introduced into a petri dish, and a porous network structure is constructed using a poor solvent-induced phase separation technique until the filter membrane is fully formed;

[0015] 3) Discard the remaining unsuitable solvent from step 2), retain the filter membrane, add AIE photosensitizer solution to the surface of the filter membrane, load and wash to achieve one-sided modification of the filter membrane; when performing asymmetric modification on the surface of the filter membrane, keep the filter membrane on the substrate plate and utilize the openness of the front side of the filter membrane to achieve its one-sided modification; AIE photosensitizer molecules have good solubility in water and ethanol and have a high positive potential (24.9mV), which can generate strong electrostatic forces with the negative potential filter membrane (-8.5mV).

[0016] 4) The modified filter membrane is vacuum dried to obtain the Janus air filter membrane.

[0017] Preferably, the biomass material in step 1) is one or two of sodium hyaluronate, soybean polysaccharide, starch, cellulose and gelatin.

[0018] Preferably, in step 1), the solvent is one of anhydrous ethanol, methanol, and acetone, and the volume ratio of water to solvent is 1:(0.4-0.9); in step 2), the unsuitable solvent is one or more of methanol, ethanol, glycerol, acetone, dimethyl sulfoxide, dimethylformamide, ethyl acetate, methyl acetate, cyclohexane, dichloromethane, and petroleum ether.

[0019] Preferably, the concentration of the AIE photosensitizer solution in step 3) is 0.3-0.5 mmol / L.

[0020] Thirdly, the application of the Janus air filter membrane, which integrates bioaerosol capture, detection, and sterilization, is disclosed in the fields of bioaerosol filtration, capture, detection, and sterilization. The air filter membrane can be used on different surfaces according to requirements. For sampling for detection purposes, the capture surface is used, and the sampled air filter membrane is directly placed in a petri dish for colony counting after incubation, or it can be directly dissolved in water for rapid quantitative detection using ATP bioluminescence, or it can be incubated and then visualized using fluorescence imaging. For sampling for sterilization purposes, the AIE photosensitive surface is required, which effectively removes and inactivates bioaerosols in the environment through air filtration and photodynamic effects under light.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention prepares an air filter membrane material with a Janus structure through phase separation and asymmetric modification. The preparation method is simple and effective. By controlling the one-sided introduction of the amphiphilic AIE photosensitizer, the performance advantages of the near-infrared AIE photosensitizer are further introduced while maintaining its original green capture performance, thus realizing the integrated performance of bioaerosol filtration, capture, detection and sterilization.

[0023] 2. The Janus air filter membrane prepared in this invention is suitable for various microbial detection methods. It maximizes sample transfer after bioaerosol sampling, facilitating accurate monitoring of airborne microorganisms. The sampled air filter membrane can be directly placed in a petri dish for colony counting after incubation, or it can be directly dissolved in water to extract captured microorganisms for rapid quantitative detection via ATP bioluminescence. Importantly, the loaded AIE photosensitizer can effectively transfect various microorganisms, and staining of the captured microorganisms can be achieved after incubation for visual detection under near-infrared fluorescence imaging.

[0024] 3. The Janus structure described in this invention allows the AIE photosensitizer to be abundantly concentrated on the front side of the filter membrane, enabling it to fully receive light and avoiding dispersion and weakening after the generation of reactive oxygen species. This effectively exerts the photodynamic bactericidal effect, thereby achieving efficient inactivation of captured microorganisms. This surface-dependent disinfection function under light is beneficial for timely control and on-demand disinfection of airborne microbial pollution. Attached Figure Description

[0025] Figure 1 A photograph of the Janus air filter membrane prepared in Example 1 of this invention;

[0026] Figure 2 The front view (A) of the Janus air filter membrane prepared in Example 1 of the present invention is compared with the front view (B) of the membrane material prepared in Comparative Example 1 without surface modification, under the same magnification.

[0027] Figure 3 SEM images of the front (A) and back (B) sides of the membrane material prepared in Comparative Example 1;

[0028] Figure 4 Image comparison of HAFM, AIE-HAFM-1, AIE-HAFM-2 and AIE-HAFM filter membranes prepared in Comparative Examples 1-3 and Example 2;

[0029] Figure 5 This is a comparison of the ultraviolet absorption spectra of the membrane solutions obtained after dissolving the membrane materials prepared in Example 2, Comparative Examples 2 and 3 in water;

[0030] Figure 6 Image of the filter membrane prepared for Comparative Example 4 that does not possess the Janus structure but has been surface modified;

[0031] Figure 7 This is a diagram showing the changes of the Janus air filter membrane prepared in Example 2 of the present invention before and after immersion in water;

[0032] Figure 8SEM images showing the changes in the microstructure of the membrane material (A) prepared in Comparative Example 1 and the Janus air filter membrane (B) prepared in Example 2 of this invention after exposure to water.

[0033] Figure 9 The membrane solution (0-20 mg / mL) prepared using the Janus air filter membrane in Example 2 of this invention is effective against Escherichia coli (E. coli). E. coli ) and Staphylococcus aureus ( S.aureus The effect on cell viability;

[0034] Figure 10 The AIE photosensitizer and the Janus air filter membrane prepared in Example 2 of this invention are effective against Escherichia coli (E. coli). E. coli ) and Staphylococcus aureus ( S.aureus Near-infrared fluorescence imaging;

[0035] Figure 11 Filter membranes prepared with different amounts of AIE photosensitizer (where HAFM, AIE-HAFM-1, AIE-HAFM, and AIE-HAFM-2 correspond to filter membranes prepared in Comparative Examples 1, 2, 2, and 3, respectively) were tested for their effectiveness against Escherichia coli under light and shadow conditions. E. coli ) and Staphylococcus aureus ( S.aureus The killing effect of ) , WL represents white light irradiation;

[0036] Figure 12 SEM images of the microstructure of the Janus air filter membrane prepared in Example 2 of this invention after bioaerosol sampling, showing the front and back sides.

[0037] Figure 13 Images showing the changes that occurred when the Janus air filter membrane prepared in Example 2 of this invention was directly placed in a petri dish after bioaerosol sampling.

[0038] Figure 14 This is a comparison chart of the RLU values ​​of the Janus air filter membrane prepared in Example 2 of the present invention and the membrane material prepared in Comparative Example 1, after being sampled in the same bioaerosol environment and detected by ATP bioluminescence method.

[0039] Figure 15 The Janus air filter membrane prepared in Example 2 of this invention, after capturing bioaerosols, was incubated and colored to inhibit Escherichia coli (E. coli). E. coli ) and Staphylococcus aureus ( S.aureus Near-infrared fluorescence imaging;

[0040] Figure 16The Janus air filter membrane prepared in Example 2 of this invention was subjected to photodynamic killing effects under different bioaerosol environments and by selecting different surfaces for capture, with and without light. AIE-HAFM (+) and AIE-HAFM (-) represent the front and back samples of the Janus air filter membrane, respectively, and WL represents white light irradiation.

[0041] Figure 17 The Janus air filter membrane prepared in Example 2 of this invention exhibits its effectiveness against Escherichia coli (E. coli) at different bioaerosol concentrations. E. coli ) and Staphylococcus aureus ( S.aureus ) has a destructive effect. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0043] The preparation method of AIE photosensitizer is as follows: 1) (3-bromopropyl)trimethylammonium bromide (2.0 g, 7.66 mmol) and 4-methylpyridine (0.734 g, 7.88 mmol) are mixed and refluxed in DMF solution overnight under nitrogen protection. After the reaction, the mixture is separated and purified to obtain compound 1; 2) 4-bromo-4',4'-dimethoxytriphenylamine (0.192 g, 0.5 mmol), 5-aldehyde-2-thiopheneboronic acid (0.0936 g, 0.6 mmol), and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (0.0183 g, 0.5 mmol) are mixed and refluxed in DMF solution overnight under nitrogen protection. 0.025 mmol) and potassium carbonate (0.345 g) were mixed and 10 mL of a 1:1 mixture of toluene and methanol was added under nitrogen protection. The mixture was refluxed overnight and separated by column chromatography to obtain compound 2; 3) Compound 1 (70.8 mg, 0.20 mmol) and compound 2 (87.2 mg, 0.21 mmol) were dissolved in anhydrous ethanol (10 mL), and then 100 μL of piperidine was added as a catalyst. The mixture was stirred and refluxed overnight. After the reaction was complete, the mixture was cooled and the crude product was concentrated under reduced pressure. The crude product was purified by neutral alumina column chromatography using dichloromethane / methanol (50:1) as the eluent to obtain a black-red solid product, namely the AIE photosensitizer.

[0044] Example 1

[0045] This embodiment provides a method for preparing a Janus air filter membrane for integrated bioaerosol capture, detection, and disinfection, comprising the following steps:

[0046] 1) Solution preparation: First, dissolve sodium hyaluronate (0.4g) and gelatin (0.8g) in deionized water (20.0mL), place in a 60°C water bath and stir for 30min to mix thoroughly. Then add anhydrous ethanol (10mL) and continue stirring for 30min to obtain the required membrane solution.

[0047] 2) Membrane formation: Pour 3 mL of membrane solution into a 6 cm diameter petri dish, add 6 mL of anhydrous ethanol and 6 mL of ethyl acetate mixture to induce phase separation until the membrane is completely formed;

[0048] 3) Surface asymmetric modification: After removing the remaining undesirable solvent from the induced phase separation, without moving the filter membrane, add 0.5 mL of AIE photosensitizer dissolved in ethanol (0.4 mmol / L), soak for 15 min, remove the remaining photosensitizer solution and wash with ethanol;

[0049] 4) Drying: The surface-modified filter membrane is subjected to vacuum freeze-drying for 5 hours to obtain the Janus air filter membrane.

[0050] Figure 1 The image shows the Janus air filter membrane after drying. It can be seen that the AIE photosensitizing side (hereinafter referred to as the front side) turns red due to the presence of the AIE photosensitizer, while the capturing side (hereinafter referred to as the back side) remains white. Both colors can be seen on its side. Figure 2 (A) shows the microstructural changes on the front side of the filter membrane before and after modification with the AIE photosensitizer, compared with the unmodified filter membrane prepared in Comparative Example 1. Figure 2 (B) In contrast, a layer of deposits can be clearly observed on the surface of the Janus air filter membrane, but its surface still maintains a heterogeneous micro-nano porous structure, ensuring efficient interception and collection of microbial particles during the sampling process.

[0051] Example 2

[0052] 1) Solution preparation: First, dissolve sodium hyaluronate (0.4g) and gelatin (0.8g) in deionized water (20.0mL), place in a 60°C water bath and stir for 30min to mix thoroughly. Then add anhydrous ethanol (10mL) and continue stirring for 30min to obtain the required membrane solution.

[0053] 2) Membrane formation: Pour 3 mL of membrane solution into a 6 cm diameter petri dish, add 6 mL of anhydrous ethanol and 6 mL of ethyl acetate mixture to induce phase separation until the membrane is completely formed;

[0054] 3) Surface modification: After removing the remaining undesirable solvent from the induced phase separation, without moving the filter membrane, add 0.5 mL of AIE photosensitizer dissolved in ethanol (0.4 mmol / L), soak for 15 min, remove the remaining solution and wash with anhydrous ethanol;

[0055] 4) Drying: The surface-modified filter membrane was subjected to vacuum freeze-drying for 5 hours to obtain the Janus air filter membrane (AIE-HAFM). After dissolving the filter membrane in water to prepare a solution, the intensity change of the characteristic absorption peak of the AIE photosensitizer could be clearly observed in the ultraviolet absorption spectrum, such as... Figure 5 As shown.

[0056] Comparative Example 1

[0057] Unlike Example 2, this comparative example does not include step 3) surface modification with the AIE photosensitizer solution. The resulting film material is white and named HAFM, as shown in the SEM image below. Figure 3 As shown in the photos, the actual product is as follows. Figure 4 As shown.

[0058] Comparative Example 2

[0059] Unlike Example 2, the concentration of the AIE photosensitizer solution in step 3) of this comparative example was adjusted to 0.2 mmol / L, while the other conditions remained the same as in Example 2. This allowed for the preparation of Janus air filter membranes with different AIE photosensitizer concentrations on their surfaces. The prepared Janus filter membrane was named AIE-HAFM-1. Due to its low AIE photosensitizer concentration, its front surface was pink. Figure 4 As shown. After dissolving the filter membrane in water to prepare a solution, the intensity change of the characteristic absorption peak of the AIE photosensitizer can be clearly observed in the ultraviolet absorption spectrum, such as... Figure 5 As shown.

[0060] Comparative Example 3

[0061] Unlike Example 2, in this comparative example, the concentration of the AIE photosensitizer solution in step 3) is 0.8 mmol / L, while the other conditions are the same as in Example 2. This allows for the preparation of Janus air filter membranes with different AIE photosensitizer concentrations on their surfaces. The prepared Janus filter membrane is named AIE-HAFM-2. Due to its high AIE photosensitizer concentration, its front surface is deep red. Figure 4 As shown, by Figure 4 It can be seen that as the concentration of the AIE photosensitizer solution increases, the color of its front side gradually deepens. After dissolving the filter membrane prepared in this comparative example in water to form a solution, the intensity change of the characteristic absorption peak of the AIE photosensitizer can be clearly observed in its ultraviolet absorption spectrum, such as... Figure 5 As shown.

[0062] Comparative Example 4

[0063] Unlike Example 2, in step 1) of this comparative example, the AIE photosensitizer (0.5 mL, 0.4 mmol / L) dissolved in ethanol was directly mixed into the membrane solution for dissolution, excluding the surface modification in step 3). The rest was the same as in Example 2. At this point, the membrane solution changed directly from colorless to red, and a pink membrane could be obtained directly after the filter membrane was formed and dried. Although this method can introduce the AIE photosensitizer into the filter membrane, the filter membrane does not possess an asymmetric Janus structure, which will result in the loss of the original green capture performance. The dispersed photosensitizer can easily damage the captured microorganisms, thus affecting the accurate assessment of bioaerosols. Furthermore, this dispersed doping method will significantly reduce the photosensitizer concentration on the front side of the membrane, affecting the photodynamic sterilization effect.

[0064] Comparative Example 5

[0065] Unlike Example 2, in step 3) of this comparative example, the formed membrane is first removed from the substrate, and then an AIE photosensitizer solution is added for surface modification. The rest is the same as in Example 2. Because of the strong electrostatic interaction between the AIE photosensitizer and the filter membrane, the AIE photosensitizer molecules will coat the entire outer surface of the filter membrane for adsorption modification. Ultimately, only a pink filter membrane without a Janus structure can be obtained, with the structure shown below. Figure 6 As shown.

[0066] Comparative Example 6

[0067] Unlike Example 2, in step 3), the amount of AIE photosensitizer solution added is 0.1 mL with a concentration of 2 mmol / L, while the rest is the same as in Example 2. Although the total amount of AIE photosensitizer added is the same as in Example 2, the reduction in the total volume of the photosensitizer solution, along with the evaporation of the solvent, makes it difficult to fully cover the entire filter membrane surface during the surface modification process. The distribution of the photosensitizer will become very uneven, and the filter membrane surface cannot be fully modified.

[0068] Comparative Example 7

[0069] Unlike Example 2, in step 3), the amount of AIE photosensitizer solution added was 1 mL with a concentration of 0.2 mmol / L, while the rest was the same as in Example 2. Although the total amount of AIE photosensitizer added was the same as in Example 2, due to the reduced concentration of the photosensitizer solution, the modification effect could only reach that of Comparative Example 2 within the same time period, and the surface modification could not be completed efficiently.

[0070] Example 3: Verification of the water solubility of Janus air filter membrane

[0071] When the Janus air filter membrane prepared in Example 2 was directly immersed in water, its structure disintegrated instantly, as shown in the example. Figure 7 As shown. Figure 8 The image shows the microstructure of the filter membrane after contact with water. It can be seen that its 3D structure completely disappears upon contact with water. Its excellent water solubility is mainly due to the fact that the main component of the air filter membrane is a water-soluble membrane, self-assembled from biomolecular chains. Upon contact with water, its internal porous network structure automatically disintegrates. Furthermore, the AIE photosensitizer post-modified to its surface also possesses excellent water solubility, resulting in the final Janus air filter membrane exhibiting similarly good water solubility. This water-disintegrating characteristic makes post-sampling processing more convenient, effectively avoiding sample loss during elution and extraction, and is suitable for various post-processing detection methods.

[0072] Example 4: Biocompatibility Verification of Janus Air Filter Membrane

[0073] With Escherichia coli ( E. coli ) and Staphylococcus aureus ( S.aureus The Janus air filter membrane was evaluated by co-culturing microbial suspensions with membrane solutions of different concentrations, using representative Gram-negative and Gram-positive bacteria from the air, respectively. To avoid the influence of photodynamic effects, this part of the operation was performed under light-protected conditions. First, the Janus air filter membrane prepared in Example 2 was dissolved in LB medium to prepare a concentrated solution (40 mg / mL), and then serially diluted to different concentrations (0-20 mg / mL). Equal volumes of... E. coli and S. aureus The bacterial suspensions were prepared by uniformly mixing the bacterial solutions with membrane solutions of different concentrations. Finally, the mixed solutions were inoculated onto LB agar medium and incubated at 37°C for 48 hours. Colony counting was then performed, and the survival rate of the microorganisms was calculated. Figure 9 It shows the results at different membrane solution concentrations. E. coli and S.aureus In a comparison of microbial activity, both bacteria maintained high biological activity within the membrane solution concentration range of 0-20 mg / mL, thus demonstrating that the porous filter membrane prepared under light-protected conditions has good biocompatibility.

[0074] Example 5: Evaluation of the microbial transfection capacity of AIE photosensitizer and Janus air filter membrane

[0075] Cultivate and collect E. coli and S.aureus (10) 8CFU / mL was mixed with AIE photosensitizer aqueous solution (3µM) and Janus air filter membrane prepared in Example 2 aqueous solution (20mg / mL), respectively. After thorough dispersion by vortexing, the mixture was incubated at 37°C in the dark for 30 min. The transfected bacterial samples were collected by centrifugation, washed with PBS, and then the sample (2µL) was dropped onto a glass slide for observation using a confocal microscope. Figure 10 This shows that AIE photosensitizer molecules can effectively transfect [the virus / infect cells]. E. coli and S.aureus Both bacteria exhibited bright red fluorescence signals in the samples. Similar results were observed in the two bacteria transfected with Janus air filter membrane solution, indicating that the AIE photosensitizer molecules loaded into the air filter membrane still possess broad-spectrum transfection capabilities and can effectively stain and analyze microorganisms.

[0076] Example 6: Evaluation of the photodynamic bactericidal performance of Janus air filter membrane

[0077] Due to the strong electron donor-acceptor interaction in the conjugated structure of AIE photosensitizers, they can efficiently generate various reactive oxygen species under white light irradiation, including singlet oxygen (…). 1 O2) and hydroxyl radicals (·OH), these reactive oxygen species, both have good bactericidal effects. The photodynamic bactericidal effect of the AIE photosensitizer modified on the front side of the Janus air filter membrane against pathogenic bacteria was directly evaluated by adding bacterial solution to the filter membrane surface and supplementing with light. First, the air filter membranes prepared in Example 2 and Comparative Examples 1-3 were cut into circles of the same size, then placed directly on an agar plate. After the filter membrane was completely wetted, a concentration of 10... 4 CFU / mL bacterial suspension (20 μL, E. coli and S.aureus The drops were respectively added to the center of the filter membrane, and then irradiated under white light (24mW / cm). 2 (10 min), and finally, spread the dissolved filter membrane evenly on the surface of the petri dish, incubate at 37°C for 48 h, and then count the colonies. The control group was operated in the dark under the same conditions, without white light irradiation. Additionally, a HAFM filter membrane of the same size prepared in Comparative Example 1 was used as a blank group. Figure 11 As shown, compared with the control group that was not exposed to white light, the Janus air filter membrane exposed to light exhibited a strong bactericidal effect on microorganisms. E. coli and S.aureusThe survival rates of bacteria in the HAFM filter membrane decreased to 3.2% and 2.0%, respectively. In contrast, due to the absence of photosensitizer, the bacterial colony size and survival rate in the HAFM filter membrane remained almost unchanged before and after light exposure. Furthermore, by reducing the amount of AIE photosensitizer introduced onto the filter membrane surface, the bacterial survival rate of the AIE-HAFM-1 filter membrane prepared in Comparative Example 2 still reached 40.2% after light exposure. This was mainly because the reduction in surface photosensitizer led to a decrease in photodynamic killing effect. Similarly, when the amount of AIE photosensitizer introduced onto the filter membrane surface was increased, the bacterial mortality rate of the AIE-HAFM-2 filter membrane prepared in Comparative Example 3 approached 100% after light exposure. However, excessively high concentrations of AIE photosensitizer also increased the dark toxicity of the filter membrane, and even without light, the survival rate of microorganisms still decreased significantly. These results indicate that the asymmetrically modified AIE photosensitizer molecules on the filter membrane surface have dose-dependent dark toxicity and photodynamic killing effects on pathogens, especially on… S.aureus These Gram-positive bacteria are more effectively killed. By changing the amount of AIE photosensitizer introduced onto the filter membrane surface, a balance between dark toxicity and photodynamic inactivation effects can be achieved in Janus air filter membranes, which helps in the construction of multifunctional integrated air filter membrane materials.

[0078] Example 7: Testing the bioaerosol capture performance of the Janus air filter membrane.

[0079] Various bioaerosol environments were simulated and sampled within a sealed atomization chamber to test and evaluate the bioaerosol capture performance of the Janus air filter membrane prepared in Example 2 of this invention. First, a microbial suspension (…) was generated using a bioaerosol generator. E. coli and S.aureus The bacterial suspension is atomized and used at a concentration range of 10. 4 -10 6The atomization rate was 10 L / min, with a concentration of CFU / mL and a nebulization time of 2 min. The air filter membranes prepared in Example 2 and Comparative Examples 1-3 were uniformly cut into 25 mm diameter circles and placed on an MD8 filter sampler for sampling. The sampling rate was 10 L / min, and the sampling time was 5 min. The particle concentration, particle size distribution, temperature, humidity, and pressure within the atomization chamber were recorded in real time using a particle size analyzer. By testing the change in particle concentration before and after the gas passed through the filter membrane, it was determined that the Janus air filter membrane had a 99.4% rejection rate for aerosol particles. This value is consistent with that of a simple HAFM filter membrane, and the pressure drop is also similar. This is mainly attributed to the amphiphilic nature of the AIE photosensitizer molecules, which remain well soluble in ethanol, allowing for uniform coating during asymmetric surface modification of the filter membrane without clogging the filter channels like particulate matter, thus maintaining the original rejection and capture performance of the filter membrane. Figure 12 The SEM image of the Janus air filter membrane prepared in Example 2 of this invention after bioaerosol sampling shows a large amount of accumulated particles on its surface, and no deformation or cracks were observed in its back structure after 2 hours of continuous operation. These findings demonstrate that the Janus air filter membrane possesses excellent air filtration performance, high structural stability, and can effectively trap airborne microbial particles, achieving effective capture of bioaerosols.

[0080] Example 8: Feasibility analysis of combining Janus air filter membrane sampling with colony culture and ATP bioluminescence methods.

[0081] The Janus air filter membrane has excellent water solubility. The air filter membrane prepared in Example 2 was sampled in a bioaerosol simulation environment using the method in Example 7. After sampling, it was placed in a petri dish and automatically absorbed water and disintegrated. After being evenly coated on the surface of the petri dish, it could be successfully inoculated with captured microorganisms. After incubation at 37°C for 48 hours, colony counting was performed, thus realizing the culture method detection of captured microorganisms. Figure 13 The changes of the Janus air filter membrane after being placed in a petri dish are shown, clearly demonstrating its rapid water absorption and automatic disintegration characteristics. To achieve rapid quantitative detection of microorganisms captured by the filter membrane, the sampled membrane can be directly dissolved in water, centrifuged, and the captured airborne microorganisms collected. After microbial lysis, a luciferin / luciferase solution (100 µL, enhanced ATP assay kit) is added. Based on the linear relationship between ATP bioluminescence intensity (RLU) and colony count (CFU), the corresponding number of captured microorganisms can be estimated by testing the RLU value. Figure 14The diagram shows the relationship between the RLU values ​​obtained by sampling the Janus air filter membrane prepared in Example 2 and the HAFM filter membrane prepared in Comparative Example 1 under the same bioaerosol environment, measured by ATP bioluminescence method. It can be observed that the two values ​​are consistent, indicating that the microorganisms captured and collected by the Janus air filter membrane can also be well combined with ATP bioluminescence method for rapid quantitative detection of airborne pathogens.

[0082] Example 9: Visual Detection and Evaluation of Bioaerosols by the Janus Air Filter Membrane

[0083] Based on the Janus air filter membrane prepared in Example 2 of this invention, samples were collected from... E. coli and S.aureus Bioaerosols were obtained by nebulizing bacterial suspensions. After collection, the air filter membrane was directly transferred into centrifuge tubes and dissolved in PBS. After thorough dispersion by vortexing, the mixture was incubated at 37°C in the dark for 30 min. The transfected samples were collected by centrifugation, washed with PBS, and then 2 µL of the sample was dropped onto a glass slide for observation using a confocal microscope. Figure 15 The Janus air filter membrane was shown to effectively capture and transfect two types of bacteria, with bright red fluorescent signals observed in both samples. This broad-spectrum visualization detection method has significant application potential in tracking and exploring unknown bioaerosols.

[0084] Example 10: Evaluation of the bioaerosol elimination performance of the Janus air filter membrane

[0085] Because the AIE photosensitizer is concentrated on the front side of the air filter membrane, the photodynamic bactericidal performance of the Janus air filter membrane exhibits a significant surface dependence. To further investigate the photodynamic bactericidal effect of the Janus air filter membrane under light induction, three different microorganisms were created in the atomization chamber using the method described in Example 7. E. coli, S.aureus The microbial killing effect of the air filter membrane prepared in Example 2 was analyzed by colony counting in a bioaerosol simulated environment (with mixed bacteria). Figure 16 The study demonstrates the effectiveness of the Janus air filter membrane in eliminating captured microorganisms under varying conditions of bioaerosol sampling, with and without light exposure. Microorganisms collected from the back of the Janus air filter membrane showed little difference in colony numbers regardless of light exposure, as the back lacks photosensitizers. In contrast, microorganisms collected from the front of the Janus air filter membrane were almost entirely killed after white light irradiation, while bacteria not exposed to white light showed good growth. Furthermore, the Janus air filter membrane exhibited significant elimination effects on bioaerosols at different concentrations. Figure 17), at an aerosol concentration of 10 6 At CFU / mL, for E. coli and S.aureus The kill rates can reach 99.4% and 99.7%, respectively. These results indicate that the photodynamic sterilization effect of the Janus air filter membrane has significant surface dependence and light control, and the on-demand sterilization of bioaerosols can be achieved by selecting the filter membrane capture surface and controlling the light.

[0086] This invention presents a Janus air filter membrane for integrated bioaerosol capture, detection, and sterilization based on an asymmetric self-assembly strategy. Compared to ordinary filter membranes, the Janus air filter membrane prepared in this invention possesses a soluble micro / nano porous network structure for efficient capture of bioaerosol particles, exhibiting advantages such as high retention efficiency, low pressure drop, large sample loading capacity, large sample transfer capacity, and flexible post-sampling processing. Importantly, its unique Janus structure allows the introduced AIE photosensitizer to asymmetrically aggregate on the front side of the filter membrane without affecting the overall membrane properties. While maintaining its original green capture properties, it also exhibits strong near-infrared fluorescence emission and high reactive oxygen species generation capacity. The Janus air filter membrane prepared in this invention can not only achieve efficient capture and enrichment of bioaerosols for rapid quantitative detection or near-infrared fluorescence-guided microbial visualization, but also achieve effective photodynamic inactivation of airborne pathogens with the aid of light. This multifunctional integration can effectively overcome the limitations of traditional single detection and sterilization modes, and can simultaneously meet the needs of effective capture, dynamic detection and on-demand disinfection of bioaerosols, providing a new approach for the intelligent prevention and control of airborne microbial pollution.

Claims

1. Janus air filtration membrane for integrated bioaerosol capture detection decontamination, characterized in that, The air filtration membrane has an asymmetric two-face structure and a soluble porous network structure, is formed by asymmetric modification of the surface of the filtration membrane by an AIE photosensitizer, and the Janus structure is constructed on the basis of not damaging the overall structure of the filtration membrane, so that the AIE photosensitizer is aggregated on one side of the filtration membrane, and the air filtration membrane has green capturing, detecting performance and photodynamic sterilization performance. The AIE photosensitizer is an amphiphilic molecule, can be dissolved in an organic solvent for asymmetric modification of the surface of the filtration membrane, and can also be dissolved in water. The structural formula of the AIE photosensitizer is: ； The preparation method of the Janus air filtration membrane for biological aerosol capturing, detecting and sterilizing integration comprises the following steps: 1) Dissolve the biomass material in water, heat and stir, add a solvent until complete dissolution, and obtain a stable membrane solution; 2) Introduce the membrane solution into a flat dish, construct a porous network structure by a poor solvent induced phase separation technology, and until the filtration membrane is completely formed; 3) Discard the remaining poor solvent of step 2), retain the filtration membrane, add an AIE photosensitizer solution on the surface of the filtration membrane, wash after loading, and realize the modification of one side of the filtration membrane; 4) Vacuum dry the modified filtration membrane to obtain the air filtration membrane.

2. The Janus air filtration membrane for integrated bioaerosol capture, detection, decontamination of claim 1, wherein, The AIE photosensitizer introduced into the air filtration membrane has a broad-spectrum microbial transfection ability, can effectively stain gram-positive and negative bacteria, and can realize visual detection of the captured microorganisms under the guidance of near-infrared fluorescence imaging.

3. The Janus air filtration membrane for integrated bioaerosol capture, detection, decontamination of claim 1, wherein, The asymmetric two-face structure includes a capturing surface and an AIE photosensitive surface, and the capturing, detection and sterilization of the microbial aerosol are realized by selecting the capturing surface and the AIE photosensitive surface.

4. The Janus air filtration membrane for integrated bioaerosol capture, detection, decontamination of claim 1, wherein, The biomass material in step 1) is one or two of sodium hyaluronate, soybean polysaccharide, starch, cellulose and gelatin.

5. The Janus air filtration membrane for integrated bioaerosol capture, detection, decontamination of claim 1, wherein, The solvent in step 1) is one of anhydrous ethanol, methanol and acetone, and the volume ratio of water to the solvent is 1:(0.4-0.9); the poor solvent in step 2) is one or more of methanol, ethanol, glycerol, acetone, dimethyl sulfoxide, dimethyl formamide, ethyl acetate, methyl acetate, cyclohexane, dichloromethane and petroleum ether.

6. The Janus air filtration membrane for integrated bioaerosol capture, detection, decontamination of claim 1, wherein, The concentration of the AIE photosensitizer solution in step 3) is 0.3-0.5 mmol / L.

7. The Janus air filtration membrane for bioaerosol capture, detection, and disinfection integration according to any one of claims 1-3 for use in bioaerosol filtration capture, detection, and disinfection, characterized in that, The air filtration membrane can be used according to the needs of different surfaces; for sampling for the purpose of detection, the capturing surface is used, the sampled air filtration membrane is directly placed in a culture dish for colony counting detection after culture, or is directly dissolved in water for rapid quantitative detection by ATP bioluminescence method, or is visualized for air microorganisms by fluorescence imaging after incubation; for sampling for the purpose of sterilization, the AIE photosensitive surface is used, and through air filtration and photodynamic effect under light, the biological aerosol in the environment is effectively removed and inactivated.

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