A functional fiber membrane for bacterial visual monitoring and response antibacterial and its preparation method and use

Abstract

The application provides a functional fiber membrane for bacterial visual monitoring and response antibacterial and a preparation method and application thereof, and belongs to the field of biological medical materials. The functional fiber membrane is a fiber membrane with a double-layer structure. A lower membrane of the fiber membrane is prepared from TCS@ZIF-8 nanoparticles and poly-epsilon-caprolactone as raw materials. An upper membrane of the fiber membrane is prepared from poly-epsilon-caprolactone, polyethylene glycol and bromo-musk toluene phenol blue as raw materials. The TCS@ZIF-8 nanoparticles are prepared from the following raw materials in a weight ratio: zinc nitrate hexahydrate 1-5 parts, triclosan 1-5 parts and 2-methyl imidazole 1-5 parts. The functional fiber membrane can realize naked-eye monitoring of various bacteria in a short time, has high monitoring sensitivity and can meet the clinical diagnosis requirements. Meanwhile, the membrane has excellent antibacterial performance and can synergistically antibacterial with photocatalysis. The functional fiber membrane has a simple preparation process, is convenient to operate and is convenient to carry, provides a feasible scheme for bacterial monitoring and has application prospects.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, specifically relating to a functional fiber membrane for visual monitoring and responsive antibacterial activity of bacteria, its preparation method, and its applications. Background Technology

[0002] Skin infections are among the most common infectious diseases, varying in depth and severity. Most of these infections originate from Staphylococcus aureus and β-hemolytic streptococci. However, traditional monitoring methods are time-consuming and limited by complex instruments or operator skill requirements. Therefore, developing functional materials to achieve on-site bacterial sensing and effective eradication is largely desirable in everyday life. With the increasing demand for big data and personalized medicine in healthcare, smart devices integrating real-time monitoring and on-demand treatment have gained increasing attention. To date, advanced flexible bandages and various sensors have been developed to monitor and treat wound infections. However, many of these remain at the level of sensor integration, requiring additional power, which increases the complexity of the devices and limits the convenience of real-time monitoring.

[0003] Inspired by the World Health Organization's (WHO) global action plan, the development of portable and inexpensive devices for monitoring and treating bacterial infections is underway. Thin-film-based devices offer unique advantages such as biosafety, efficiency, portability, visualization, and low cost, and have been widely applied in artificial intelligence-based detection and screening of human health. In the diagnosis of bacterial infections, the unique microenvironment of bacteria (pH, toxins, enzymes, etc.) facilitates research. pH is a particularly interesting parameter, related to bacterial growth and metabolism, as many bacteria break down organic matter to produce acids, and it has been widely used in the detection of bacterial infections. Considering that color is an important visual perception and can be easily monitored, several color-changing thin-film devices for monitoring bacteria have been developed. Hydrogel-based color-changing wound dressings have shown advantages in using color-changing technology for wound monitoring. Furthermore, electrospun fibers exhibit a high surface-to-volume ratio and mimic the structure of the extracellular matrix (ECM), allowing different types of drugs to bind to the primary matrix, also showing potential as pH monitoring sensors.

[0004] Routine pathogen identification primarily involves observing cell morphology, Gram staining, culture, and biochemical analysis. Besides enzyme-linked immunosorbent assays (ELISA), polymerase chain reaction (PCR), and culture-based assays, there are instrument-based methods such as flow cytometry and gas chromatography, as well as spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. While these methods may possess sensitivity and specificity, they require extensive sample preparation, demand skilled personnel, are expensive, and can potentially increase the total testing time to over 18 hours, making them unsuitable for field applications. Summary of the Invention

[0005] The purpose of this invention is to provide a functional fiber membrane for bacterial visual monitoring and responsive antibacterial treatment, as well as its preparation method and applications.

[0006] This invention provides a functional fiber membrane for visual monitoring and responsive antibacterial action of bacteria, which is a fiber membrane with a bilayer structure;

[0007] The lower layer of the fiber membrane is prepared from TCS@ZIF-8 nanoparticles and poly(ε-caprolactone) as raw materials;

[0008] The upper layer of the fiber membrane is prepared from poly(ε-caprolactone), polyethylene glycol, and bromothymol blue.

[0009] The TCS@ZIF-8 nanoparticles were prepared from the following raw materials in the following weight ratios: 1-5 parts zinc nitrate hexahydrate, 1-5 parts triclosan, and 1-5 parts 2-methylimidazole.

[0010] Furthermore, the TCS@ZIF-8 nanoparticles are prepared from the following raw materials in the following weight ratio: 1.5 parts zinc nitrate hexahydrate, 1 part triclosan, and 3.3 parts 2-methylimidazole.

[0011] Furthermore, the preparation method of the TCS@ZIF-8 nanoparticles includes the following steps:

[0012] (1) Dissolve zinc nitrate hexahydrate in a solvent;

[0013] (2) Dissolve 2-methylimidazole in a solvent;

[0014] (3) Add triclosan to the solution obtained in step (1), then add the solution obtained in step (2), stir, centrifuge and dry to obtain TCS@ZIF-8 nanoparticles;

[0015] Preferably,

[0016] In step (1), the solvent is methanol or water;

[0017] And / or, in step (2), the solvent is methanol or water.

[0018] Furthermore, the lower layer of the fiber membrane is obtained by spinning a spinning solution made from TCS@ZIF-8 nanoparticles and poly(ε-caprolactone).

[0019] The method for preparing the spinning solution includes the following steps:

[0020] A) Dissolve poly-ε-caprolactone in a solvent to obtain a poly-ε-caprolactone spinning solution with a poly-ε-caprolactone concentration of 5-10 wt%.

[0021] B) Add TCS@ZIF-8 nanoparticles to a solvent and disperse them evenly to obtain a dispersion with a TCS@ZIF-8 nanoparticle concentration of 1-5 mg / mL.

[0022] C) Add the dispersion from step B) to the poly(ε-caprolactone) spinning solution from step A), and stir until homogeneous to obtain the final product.

[0023] Furthermore,

[0024] In step A), the solvent is hexafluoroisopropanol, N,N-dimethylformamide, or N,N-dimethylacetamide;

[0025] And / or, in step A), the concentration of the poly-ε-caprolactone is 8 wt%;

[0026] And / or, in step B), the solvent is ethanol;

[0027] And / or, in step B), the concentration of the TCS@ZIF-8 nanoparticles is 2 mg / mL;

[0028] And / or, in step C), the volume-to-mass ratio of the dispersion in step B) to the poly(ε-caprolactone) spinning solution in step A) is 1 ml: 20 g.

[0029] Furthermore, the upper layer of the fiber membrane is obtained by spinning after preparing a spinning solution using poly(ε-caprolactone), polyethylene glycol, and bromothymol blue as raw materials;

[0030] The method for preparing the spinning solution includes the following steps:

[0031] i) Poly(ε-caprolactone) and polyethylene glycol are dissolved in a solvent to obtain a mixed spinning solution in which the concentration of poly(ε-caprolactone) is 5-10 wt% and the concentration of polyethylene glycol is 5-10 wt%.

[0032] ii) Dissolve bromothymol blue in a solvent to obtain a bromothymol blue solution with a concentration of 10-20 mg / mL;

[0033] iii) Add the bromothymol blue solution from step ii) to the mixed spinning solution from step i), stir until homogeneous, and the product is obtained;

[0034] Preferably,

[0035] In step i), the solvent is hexafluoroisopropanol, N,N-dimethylformamide, or N,N-dimethylacetamide;

[0036] And / or, in step i), the concentration of PCL is 7.4 wt% and the concentration of PEG is 7.4 wt%.

[0037] And / or, in step ii), the solvent is ethanol;

[0038] And / or, in step ii), the concentration of the bromothymol blue solution is 12 mg / mL;

[0039] And / or, in step iii), the volume-to-mass ratio of the bromothymol blue solution in step ii) to the mixed spinning solution in step i) is 1 ml: 20 g.

[0040] Furthermore, the lower layer of the fiber membrane is spun by electrospinning;

[0041] The electrospinning parameters are as follows: positive voltage: 10-15kV, negative voltage: 0.5-1kV, working distance between needle tip and current collector: 8-15cm, extrusion speed: 0.5-1.5mL / h, and spinning time: 1.5-3h.

[0042] Preferably, the electrospinning parameters are: positive voltage 14kV, negative voltage 0.5kV, working distance between needle tip and current collector 10cm, extrusion speed 1.0mL / h, and spinning time 2h.

[0043] Furthermore, the spinning method for the upper layer of the fiber membrane is electrospinning;

[0044] The electrospinning parameters are as follows: positive voltage: 10-15kV, negative voltage: 0.5-1kV, working distance between needle tip and current collector: 8-15cm, extrusion speed: 0.5-1.5mL / h, and spinning time: 3-6h.

[0045] Preferably, the electrospinning parameters are: positive voltage 14kV, negative voltage 0.5kV, working distance between needle tip and current collector 10cm, extrusion speed 1.0mL / h, and spinning time 4h.

[0046] The present invention also provides a method for preparing the aforementioned functional fiber membrane, which includes the following steps:

[0047] (a) After preparing a spinning solution using TCS@ZIF-8 nanoparticles and poly(ε-caprolactone) as raw materials, the lower layer of the fiber membrane is obtained by spinning.

[0048] (b) After preparing a spinning solution using poly(ε-caprolactone), polyethylene glycol and bromothymol blue as raw materials, the solution is spun on the lower membrane to obtain a double-layer fiber membrane, which is the functional fiber membrane.

[0049] The present invention also provides the use of the aforementioned functional fiber membrane in the preparation of materials and / or devices for visual monitoring of bacteria and / or antibacterial activity;

[0050] Preferably, the bacteria are Escherichia coli, Staphylococcus aureus, and / or Candida albicans.

[0051] This invention prepares a functional fiber membrane that integrates visual monitoring of bacteria and responsive antibacterial action. The membrane is an electrospun membrane (PPBT). It utilizes the acidity of the microenvironment caused by bacterial metabolism. On the one hand, the bromothymol blue (BTB) on the PPBT changes color from green to yellow under acidic conditions. On the other hand, the TCS@ZIF-8 nanoparticles loaded on the PPBT membrane disintegrate and release TCS under acidic conditions, and simultaneously generate ROS under photocatalytic conditions to achieve a synergistic antibacterial effect.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0053] This invention provides an electrospun membrane that integrates visual bacterial monitoring and responsive antibacterial action. This membrane not only enables real-time visual monitoring of bacteria through color changes, but also features a short detection time (2-4 hours) and high detection sensitivity (detection limit of 10). 4 The membrane (CFU / mL) meets clinical diagnostic needs; furthermore, it exhibits excellent antibacterial effects and achieves synergistic antibacterial action under photocatalysis. The electrospun membrane preparation process of this invention is simple, convenient, and portable, providing a feasible solution for preparing antibacterial materials integrating bacterial monitoring and antibacterial functions, and has promising application prospects.

[0054] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0055] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0056] Figure 1Morphological characterization results of TCS@ZIF-8 nanoparticles and fiber membranes: a) SEM image of TCS@ZIF-8 nanoparticles; b) TEM image of TCS@ZIF-8 nanoparticles and elemental distribution; c) SEM images of each fiber membrane; d) EDS distribution of Zn element in PCL+TZ fiber membranes.

[0057] Figure 2 Infrared spectra of each fiber membrane and TCS@ZIF-8 nanoparticles.

[0058] Figure 3 The results of water contact angle and tensile properties tests for TCS@ZIF-8 nanoparticles and various fiber membranes are as follows: a) Water contact angle test results; b) Tensile property test results.

[0059] Figure 4 The following diagrams show the results of the BTB colorimetric mechanism: a) BTB full-spectrum scanning spectrum at different pH values ​​(8.0–5.5); b) absorbance change at 615 nm when pH decreases from 8.0 to 5.5; c) absorbance at 615 nm of E. coli solution; d) absorbance at 615 nm of S. aureus solution.

[0060] Figure 5 Drug release results on TCS@ZIF-8 nanoparticles and PPBT membranes: a) Acid release experiment results of TCS@ZIF-8 nanoparticles; b) Acid release experiment results of PPBT membranes.

[0061] Figure 6 Results of the antibacterial properties of TCS@ZIF-8 nanoparticles and ZIF-8 nanoparticles: a) Colony diagram; b) Survival rate of S. aureus after treatment with TCS@ZIF-8 nanoparticles and ZIF-8 nanoparticles; c) Survival rate of E. coli after treatment with TCS@ZIF-8 nanoparticles and ZIF-8 nanoparticles.

[0062] Figure 7 The monitoring results of the membrane on E. coli and S. aureus are as follows: a) acid-triggered color change of PPBT membrane after culturing with different concentrations of E. coli and S. aureus for 4 h; b) color change intensity of PPBT membrane after culturing with different concentrations of E. coli and S. aureus for 4 h; c) fluorescence staining images of PPBT membrane after culturing with different concentrations of E. coli and S. aureus for 4 h.

[0063] Figure 8 Macroscopic images and intensity of color changes triggered by acid after 4 hours of culturing PPBT membranes with different concentrations of Candida albicans.

[0064] Figure 9Antibacterial effects of various fiber membranes: a) Images of live and dead bacteria (bacterial concentration 10). 6 b represents the antibacterial properties of each fiber membrane (bacterial concentration of 10). 6 c shows SEM images of bacteria on each fiber membrane (bacterial concentration is 10). 6 ); d represents the number of bacteria surviving on each fiber membrane at different concentrations. Detailed Implementation

[0065] The raw materials and equipment used in the specific embodiments of the present invention are all known products, obtained by purchasing commercially available products.

[0066] Among them, poly(ε-caprolactone) (PCL, average molecular weight 80,000) was from Sigma; 2-methylimidazole and zinc nitrate hexahydrate were purchased from Aladdin; triclosan (TCS), hexafluoroisopropanol (HFIP), and polyethylene glycol (PEG, average molecular weight 10,000) were from Bailingwei Technology; potassium dihydrogen phosphate, sodium chloride, potassium chloride, agar powder, yeast extract powder, and methanol were from Chengdu Kelong Chemical Co., Ltd.; tryptone was from Beijing Aoboxing Biotechnology Co., Ltd.; and Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538), and Candida albicans (ATCC 10231) were from Shanghai Luwei Technology Co., Ltd.

[0067] In this invention, the concentrations of methanol and ethanol are not mentioned; both are referred to as anhydrous methanol and anhydrous ethanol.

[0068] Example 1: Preparation of the functional fiber membrane of the present invention

[0069] 1. Synthesis of TCS@ZIF-8 nanoparticles

[0070] 1.5 g of Zn(NO3)2·6H2O was dissolved in 56.5 g of methanol. 1.0 g of TCS was added and dissolved, followed by the addition of a 56.5 g methanol solution containing 3.3 g of 2-methylimidazole. The mixture was stirred at room temperature for 24 h. The resulting product (TCS@ZIF-8 nanoparticles, TCS@ZIF-8NPs) was washed four times with ethanol and dried under vacuum at room temperature.

[0071] Using the above method without adding TCS, pure ZIF-8 nanoparticles (ZIF-8NPs) were prepared as a control.

[0072] 2. Preparation of PCL electrospun film loaded with TCS@ZIF-8 nanoparticles

[0073] A spinning solution for PCL (8 wt%, solvent: HFIP) was prepared. 2 mg of TCS@ZIF-8 nanoparticles were added to 1 ml of ethanol and ultrasonically dispersed for 5 min. The ethanol dispersion of TCS@ZIF-8 nanoparticles was added to 20 g of the PCL spinning solution, stirred thoroughly, and then transferred to a syringe (21 G needle size) for electrospinning. The spinning parameters were: applied positive and negative voltages of 14 kV and 0.5 kV, respectively; working distance between the needle tip and the current collector of 10 cm; and spinning at an extrusion speed of 1.0 mL / h for 2 h to obtain a monolayer PCL electrospun membrane (monolayer fiber membrane) loaded with TCS@ZIF-8 nanoparticles.

[0074] 3. Preparation of double-layer electrospun film

[0075] Prepare a mixed spinning solution of PCL and PEG (solvent is HFIP), with the mass percentage of PCL and PEG both being 7.4 wt%. Weigh 20 g of the mixed spinning solution of PCL and PEG and add it to 1.0 mL of ethanol solution containing 12 mg of bromothymol blue (BTB). Stir the mixed spinning solution evenly and transfer it to a syringe (syringe needle size is 21 G). Continue electrospinning on a single-layer PCL electrospun membrane loaded with TCS@ZIF-8 nanoparticles (single-layer fiber membrane) to obtain a double-layer fiber membrane (after the single-layer PCL electrospun membrane loaded with TCS@ZIF-8 nanoparticles is finished spinning, do not remove it from the receiving device, only change the spinning solution and continue spinning. The new membrane will cover the original membrane, forming a double-layer electrospun membrane with upper and lower layers). The spinning parameters were set as follows: the applied positive and negative voltages were 14kV and 0.5kV, respectively; the working distance between the needle tip and the current collector was 10cm; the extrusion speed of the spinning solution was 1.0mL / h; and the spinning time was 4h.

[0076] The following specific experimental examples demonstrate the beneficial effects of the present invention.

[0077] Experimental Example 1: Morphological Characterization of TCS@ZIF-8 Nanoparticles and Fiber Membranes

[0078] The TCS@ZIF-8 nanoparticles and fiber membranes prepared in Example 1 were characterized by SEM and TEM for microstructure and by FT-IR for structural characterization.

[0079] This invention successfully synthesized TCS@ZIF-8 nanoparticles (TCS@ZIF-8NPs) using a room-temperature solution reaction method. (SEM image) Figure 1 a) indicates that the synthesized TCS@ZIF-8NPs have a hexahedral structure with sharp edges and a diameter of approximately (50-500 nm). Furthermore, in the transmission images of the TCS@ZIF-8NPs crystals ( Figure 1(b) The elemental distribution of Zn, C, O, N, and Cl is uniform (TEM), indicating that triclosan TCS was successfully loaded into nanoparticles, resulting in an increased particle diameter. The results demonstrate the successful synthesis of core-shell structured TCS@ZIF-8NPs with a regular and uniform morphology.

[0080] SEM images of the prepared fiber membranes are as follows: Figure 1 As shown in c. Figure 1 In step c, PCL is a pure PCL membrane, PPB is a single-layer membrane obtained by electrospinning according to the spinning parameters after preparing a mixed spinning solution (containing BTB) according to the "3. Preparation of Bilayer Electrospun Membrane" in Example 1, and PCL+TZ is the PCL electrospun membrane (single-layer membrane) loaded with TCS@ZIF-8 nanoparticles prepared in Example 1. The preparation method of the pure PCL membrane is as follows: Prepare a PCL spinning solution (8wt%, solvent is HFIP), transfer the spinning solution to a syringe (syringe needle size is 21G) for spinning, with the applied positive and negative voltages set to 14kV and 0.5kV respectively, the working distance between the needle tip and the current collector set to 10cm, and spinning for 2h at an extrusion speed of 1.0mL / h to obtain a pure PCL membrane. Figure 1 As shown in c: the fibers on the pure PCL membrane are relatively straight and uniform; the membrane with added TCS@ZIF-8 nanoparticles (PCL+TZ) is relatively rough; the PPB fibers in the PEG and BTB blended membrane are of uneven thickness. Furthermore, EDS shows that Zn is relatively uniformly distributed on the surface of the PCL+TZ membrane. Figure 1 d) indicates that the fiber contains TCS@ZIF-8 nanoparticles.

[0081] Infrared spectrum as follows Figure 2 As shown: 2944cm -1 And 2863cm -1 The CH molecules belonging to the PCL molecular chain undergo asymmetric and symmetric stretching, 1722 cm. -1 Carbonyl stretching. 1100cm after adding PEG to PCL. -1 It is the stretching vibration of COC that is strengthened, 1163cm -1 It is a benzene ring CO, with a wavelength of 1188 cm. -1 The absorption band is attributed to O=S=O, 1046 cm⁻¹ -1 Attributable to SOC, this proves the presence of BTB on the PPB membrane. 1309 cm⁻¹ -1 1146cm -1 and 758cm -1 This is attributed to the planar bending of the imidazole ring. 1444cm -1 Corresponding to planar stretching of the imidazole ring. 1149cm -1The presence of TCS@ZIF-8 in PCL+TCS@ZIF-8, along with the Zn elemental distribution observed in SEM and TEM, confirms the successful synthesis of TCS@ZIF-8 and its loading onto the membrane. Figure 2 In this context, TCS@ZIF-8 refers to the TCS@ZIF-8 nanoparticles prepared in Example 1, PCL is a pure PCL membrane (prepared as described above), PCL+TCS@ZIF-8 is a PCL electrospun membrane (monolayer) loaded with TCS@ZIF-8 nanoparticles prepared in Example 1, PCL+PEG is a fiber membrane (monolayer) prepared using only a mixed spinning solution of PCL and PEG, and PCL+PEG+BTB is a monolayer membrane obtained by electrospinning according to the spinning parameters after preparing a mixed spinning solution (containing BTB) according to "3. Preparation of bilayer electrospun membrane" in Example 1. The preparation method of PCL+PEG is as follows: a mixed spinning solution of PCL and PEG (solvent is HFIP) is prepared, and the mass percentage of PCL and PEG is 7.4 wt%. The mixed spinning solution of PCL and PEG is transferred to a syringe (syringe needle size is 21G) for spinning. The spinning parameters are: the applied positive and negative voltages are set to 14 kV and 0.5 kV respectively, the working distance between the needle tip and the current collector is set to 10 cm, and spinning is carried out at an extrusion speed of 1.0 mL / h for 4 h to obtain a pure PCL+PEG film.

[0082] Test Example 2: Surface wettability test

[0083] The TCS@ZIF-8 nanoparticles and fiber membranes prepared in Example 1 were used to measure the surface wettability of the fiber membrane using a water contact angle meter (HKCA-40, China) (using 3 μL water droplets to test five different points).

[0084] PCL: Prepare a hexafluoroisopropanol solution with a mass percentage of 8 wt% PCL as the spinning solution. Transfer the spinning solution to a syringe (syringe needle size is 21G) for electrospinning to obtain a monolayer film. The spinning parameters are: positive voltage 14kV, negative voltage 0.5kV, working distance between needle tip and current collector is 10cm, extrusion speed is 1.0mL / h, and spinning time is 2h.

[0085] PCL+TZ: The spinning solution was prepared according to the description in "2. Preparation of PCL electrospinning membrane loaded with TCS@ZIF-8 nanoparticles" in Example 1, and the membrane was obtained by spinning according to the spinning parameters therein, which is the single-layer fiber membrane prepared in Example 1.

[0086] PCL+PEG: A mixed spinning solution of PCL and PEG (solvent: HFIP) was prepared, with PCL and PEG each accounting for 7.4 wt%. The mixed spinning solution of PCL and PEG was transferred to a syringe (21G needle size) for electrospinning to obtain a monolayer film. The spinning parameters were as follows: the applied positive and negative voltages were set to 14 kV and 0.5 kV, respectively; the working distance between the needle tip and the current collector was 10 cm; the extrusion speed was 1.0 mL / h; and the spinning time was 4 h.

[0087] PPB: A single-layer membrane obtained by electrospinning according to the spinning parameters after preparing the mixed spinning solution (containing BTB) according to "3. Preparation of double-layer electrospun membrane" in Example 1.

[0088] PPBT: A double-layer PPBT membrane is obtained by spinning a PPB membrane on a PCL+TZ membrane, which is the double-layer fiber membrane prepared in Example 1.

[0089] The wettability of each fiber membrane surface was tested using water contact angle (WCA) analysis, and the results are as follows: Figure 3 As shown in Figure a, the hydrophobicity of the film surface can be determined by the WCA value; if it exceeds 90°, it is considered hydrophobic. The WCA value of the PCL film is 134.494°, indicating that the PCL film is hydrophobic. After adding TCS@ZIF-8, the water contact angle of the film slightly increased, possibly due to the increased surface roughness caused by the doping of nanoparticles. The surface wettability of the film is related to the surface chemical properties and surface micro / nano structure. The water contact angle of the PCL+PEG blended film was significantly reduced (44.783°) due to the hydrophilicity of PEG; after adding BTB to the PCL+PEG film, the hydrophilicity of the film was further enhanced, and the water contact angle was 17.713°; while in the case of bacterial detection of the spun PPBT bilayer membrane, the water contact angle remained unchanged (17.644°) when the bacterial solution was dropped onto the PPB surface. Therefore, the prepared bilayer membrane has a large difference in hydrophilicity and hydrophobicity. The outer hydrophilic fiber layer (PPB) can quickly absorb the bacterial solution and diffuse to the entire outer fiber membrane, and fully contact BTB to facilitate acid response and color change. The inner hydrophobic surface (PCL+TZ) slows down the diffusion of the bacterial solution to the entire hydrophobic layer to contact the antibacterial particles and delays its acid release.

[0090] Test Example 3: Mechanical Performance Testing

[0091] The mechanical property test samples were the same as in Test Example 2, with the film cut into rectangles of 10.0 mm × 50.0 mm. The thickness was measured using a handheld C112XBS micrometer. The stress-strain curves were measured using a servo-controlled universal testing machine at a rate of 20.0 mm / min.

[0092] According to the tensile mechanical curve ( Figure 3(b) The effects of different components on the mechanical properties of the membrane were analyzed. The pure PCL membrane had a tensile strength of 7.9 mPa. The tensile strength of the membrane after adding TCS@ZIF-8 (PCL+TZ) decreased to 5.58 mPa, while the strain increased from 87% to 195%. The PCL+PEG membrane's tensile strength decreased to 1.62 mPa, and a yield plateau appeared at 51% strain. The strain continued to increase, but the stress remained essentially unchanged, with a maximum strain value of 200%. Adding BTB (PPB) to the PCL+PEG membrane further reduced the tensile strength (1.07 mPa), prolonged the yield plateau, and achieved a deformation of 426%. The bilayer PPBT membrane, consisting of PCL+TZ and PPB, exhibited mechanical properties influenced by the combined effects of both components, with a tensile strength of 3.1 mPa and a maximum deformation of 110%. These results indicate that the presence of PCL maintained good mechanical strength of the membrane.

[0093] Experimental Example 4: BTB Colorimetric Mechanism

[0094] Different concentrations of bacterial suspensions were added to BTB indicator solution (glucose aqueous solution) and cultured in a constant temperature and humidity incubator at 37℃ until the solution showed a color change. The supernatant of the bacterial suspension after centrifugation was aspirated and the absorbance at 615nm was measured using a UV spectrophotometer.

[0095] Figure 4 a represents the full-spectrum scan spectrum of BTB at different pH values ​​(8.0–5.5), with the characteristic peak at 615 nm increasing as pH decreases. The BTB solution changes from blue to green, and then to yellow. Figure 4 b represents the change in absorbance at 615 nm when the pH decreases from 8.0 to 5.5. When E. coli and S. aureus bacterial cultures were mixed and incubated with BTB indicator solution, the absorbance at 615 nm decreased with increasing bacterial concentration. Figure 4 This acidification is due to bacterial respiration and fermentation, which produce weakly acidic substances (e.g., carbonic acid, lactic acid).

[0096] Experimental Example 5: Drug Delivery Capacity of TCS@ZIF-8 Nanoparticles

[0097] To measure the drug loading capacity (DLC) of TCS@ZIF-8 nanoparticles, 1 mg of dried TCS@ZIF-8 nanoparticles (prepared in Example 1) was weighed and completely decomposed with 1 μL of 500M HCl, then diluted to 10 mL with DMSO. The absorbance of the solution at 280 nm was measured using a UV-Vis spectrophotometer (Unico), and the amount of TCS was calculated based on its standard curve. Finally, the DLC value of TCS@ZIF-8 was calculated according to the following formula.

[0098] DLC(%) = (M TCS ) / (M TCS@ZIF-8 )×100%

[0099] Among them, M TCS M represents the mass of the released TCS TCS@ZIF-8 This indicates the mass of the original antimicrobial particles TCS@ZIF-8.

[0100] Based on the standard curve of absorbance at 280 nm of TCS released by TCS@ZIF-8 nanoparticles under strong acid conditions, the drug loading rate of TCS loaded on TCS@ZIF-8 nanoparticles was calculated to be 5 wt%.

[0101] Experimental Example 6: TCS@ZIF-8 and Drug Release on Membrane

[0102] Drug release experiments were conducted using the dialysis bag method. TCS@ZIF-8NPs (prepared in Example 1) were placed in dialysis bags and then placed in the receptor compartment of PBS buffer (pH 5.5, 6.5, 7.4). 1.0 wt% Tween-80 was previously added to the PBS to improve the solubility and stability of triclosan. The temperature in the receptor compartment was maintained at 37°C, and aliquots were taken at fixed time points. The released drug was quantified by measuring the absorbance of triclosan at 280 nm using UV-Vis spectroscopy. Drug release studies on PPBT membranes (the bilayer fiber membrane prepared in Example 1) were conducted using the same method.

[0103] In vitro release of TCS@ZIF-8 and fibrous membranes from PBS at different pH values ​​(5.5, 6.5, 7.4) at 37℃. Figure 5 As shown. The release rate of TCS depends on time and pH. Figure 5 The results showed that under acidic conditions at pH 5.5 and 6.5, the release of TCS from TCS@ZIF-8 particles increased with time. At pH 5.5, the release of TCS@ZIF-8 particles reached 91.34% (max 93.07%) within 8 hours, compared to 50.12% at pH 6.5, while almost no release was observed in PBS at pH 7.4. Based on drug release on PPBT membranes... Figure 5 (b) It possesses a drug release capacity similar to TCS@ZIF-8 nanoparticles, and the release rate of TCS is lower than that of pure nanoparticles under acidic conditions of pH 5.5 and 6.5. Therefore, this experiment demonstrates that both the synthesized TCS@ZIF-8 particles and the TCS@ZIF-8-loaded fiber membrane (PPBT membrane) have the ability to gradually release TCS over time and with decreasing pH. The extended release time on the membrane is beneficial for achieving antibacterial effects after membrane monitoring.

[0104] Test Example 7: Antibacterial Properties

[0105] ZIF-8NPs and TCS@ZIF-8NPs were prepared according to the method described in Example 1.

[0106] Prepare ZIF-8NPs and TCS@ZIF-8NPs at different concentrations (200, 100, 50, 25, 12.5, 6.25, 3.13 μg / mL), and add 100 μL of bacterial (E. coli or S. aureus) suspension (10 6 Then, 100 μL of each group was spread onto a plate and incubated at 37°C for 18 hours. The entire experiment was conducted in the dark. The colony counts for each group were then observed, and bacterial viability was calculated. The calculation formula is as follows:

[0107] Bacterial survival rate = (Number of colonies in the experimental group) / (Number of colonies in the control group) × 100%

[0108] The control group consisted of pure bacterial cultures.

[0109] The antibacterial properties of TCS@ZIF-8NPs and ZIF-8NPs were evaluated using E. coli and S. aureus. The results showed that ( Figure 6 (a-6c) For *E. coli* and *S. aureus*, both TCS@ZIF-8NPs and ZIF-8NPs exhibited concentration-dependent antibacterial activity. ZIF-8NPs showed colony growth in both *E. coli* and *S. aureus* at 25 μg / mL, and more colonies at 12.5 μg / mL. TCS@ZIF-8NPs showed less colony growth in both *E. coli* and *S. aureus* at 12.5 μg / mL, but achieved antibacterial activity at 25 μg / mL. These results indicate that TCS@ZIF-8NPs has stronger antibacterial ability than ZIF-8NPs. Because TCS has stronger bactericidal ability, loading it onto ZIF-8NPs enhances the overall antibacterial effect of the nanoparticles.

[0110] Experimental Example 8: Bacterial Monitoring of Membranes

[0111] The prepared electrospun PPBT membrane (the double-layer electrospun membrane prepared in Example 1) was cut into several 1cm × 1cm pieces. The membranes, with the BTB-containing side facing up, were placed in a 48-well plate for later use. 100μL of bacterial suspension (8wt% glucose) of different concentrations was added to the membranes in each well. The plates were then covered and incubated in a 37℃ constant temperature and humidity incubator (incubation in the dark). The color change of the membrane was observed every half hour for a total of 4 hours. The monitoring ability of the membrane against Escherichia coli, Staphylococcus aureus, and Candida albicans was investigated.

[0112] The acid response of PPBT originates from acid-triggered color changes. First, co-culturing bacterial culture with PPBT for 4 hours resulted in concentration-dependent color changes on the membrane; higher bacterial concentrations led to greater yellowing and stronger color density. Specifically, 10-1 PPBT exhibited the most significant color change. 8 Incubation with bacterial suspensions (Escherichia coli and Staphylococcus aureus) for 1 hour resulted in a distinct yellow color on the membrane; after co-culturing for 4 hours, the membrane showed a yellow color after 10 hours. 5 The components of the bacterial culture concentration showed identifiable color changes. Figure 7 (a-7b). Furthermore, the fluorescent area emitted by membranes containing different concentrations of bacterial suspension after staining with SYTO 9 showed a gradient change; the higher the concentration, the larger the fluorescent area. Figure 7 c). For Candida albicans, 10 6 Incubation of the bacterial solution on the membrane for 1 hour resulted in a distinct yellow color on the membrane, and after co-culturing for 4 hours, 10 4 The components of the bacterial culture concentration showed identifiable color changes. Figure 8 Therefore, the prepared PPBT membrane exhibits resistance to E. coli and S. aureus. 、 C. albicans has the ability to monitor in real time.

[0113] Test Example 9: Antibacterial Properties of the Membrane

[0114] Following the method in Example 8, different concentrations of *E. coli* and *Staphylococcus aureus* bacterial suspensions cultured on various fiber membranes for 24 hours were added to 900 μL of PBS. After elution, 100 μL of each suspension was spread onto culture medium and incubated for 24 hours. The number of colonies was observed, and the antibacterial rate was calculated. LB medium was used for *E. coli* and *Staphylococcus aureus*. The formula for calculating the antibacterial rate is as follows:

[0115] Antibacterial rate = (Number of colonies in control group) - (Number of colonies in experimental group) / (Number of colonies in control group) × 100%

[0116] The control group consisted of pure bacterial cultures.

[0117] The PCL+PEG, PPB, and PPBT films were incubated in the dark, just like in Experiment 2.

[0118] The PPBT+vis group was incubated in visible light with a wavelength of 405nm.

[0119] As the co-culture time increased, the TCS@ZIF-8 loaded on the membrane released the drug due to exposure to the acidic environment. In addition, the nanoparticles generated ROS, TCS, and Zn under 405nm wavelength light irradiation. 2+ Synergistic antibacterial action is achieved to enhance the antibacterial effect, realizing the integration of monitoring and antibacterial functions. Fiber membranes and 10 6After co-culturing the bacterial culture for 24 hours, the bacteria treated with different components were observed using the dual-staining fluorescent dyes SYTO9 / PI. SYTO9 staining agent labeled all bacteria, emitting green fluorescence, while propidium iodide (PI) only labeled bacteria with damaged cell walls and membranes, emitting red fluorescence.

[0120] Figure 9 a shows the live / dead staining status of E. coli and S. aureus (bacterial concentration of 10). 6 E. coli and S. aureus on membranes without antimicrobial particles (PCL+PEG and PPB) emitted green fluorescence, indicating that the cell membrane and cell wall structure were intact. Conversely, after incubation with PPBT containing antimicrobial particles, E. coli and S. aureus showed significant red fluorescence, indicating that the cell membrane and cell wall were damaged and destroyed, resulting in the death of a large number of bacteria. When exposed to 405 nm visible light, the red signal of the PPBT group increased significantly, indicating a sharp increase in the number of dead bacteria.

[0121] Figure 9 b shows the colony growth after plating (bacterial concentration of 10). 6 ),Depend on Figure 9 b shows that PCL+PEG and PPB have virtually no antibacterial properties, while PPBT has significant antibacterial properties. Furthermore, the combined use of PPBT and visible light (Vis) can further enhance the antibacterial properties, indicating that PPBT and Vis have a synergistic antibacterial effect.

[0122] In addition, based on the SEM images of the bacteria ( Figure 9 c) In the PPBT group, the bacterial surface showed wrinkles and deformation, while the morphological damage and deformation of the PPBT+Vis group were more severe. According to Figure 9 Similarly, it can be seen that PPBT exhibits excellent antibacterial effects. The colony growth in the PPBT+Vis group under light was less than that in the PPBT group, indicating that the membrane has good photocatalytic synergistic antibacterial properties.

[0123] In summary, this invention provides an electrospun membrane that integrates visual bacterial monitoring and responsive antibacterial action. This membrane not only enables real-time visual monitoring of bacteria through color changes, but also offers short detection times (2-4 hours) and high detection sensitivity (detection limit of 10). 4 The membrane (CFU / mL) meets clinical diagnostic needs; furthermore, it exhibits excellent antibacterial effects and achieves synergistic antibacterial action under photocatalysis. The electrospun membrane preparation process of this invention is simple, convenient, and portable, providing a feasible solution for preparing antibacterial materials integrating bacterial monitoring and antibacterial functions, and has promising application prospects.

Claims

1. A functional fiber membrane for visual monitoring and responsive antimicrobial treatment of bacteria, characterized in that: It is a fiber membrane with a double-layer structure; The lower layer of the fiber membrane is obtained by spinning a spinning solution made from TCS@ZIF-8 nanoparticles and poly(ε-caprolactone). The preparation method of the spinning solution includes the following steps: A) Dissolve poly-ε-caprolactone in a solvent to obtain a poly-ε-caprolactone spinning solution with a poly-ε-caprolactone concentration of 5~10wt%; B) Add TCS@ZIF-8 nanoparticles to a solvent and disperse them evenly to obtain a dispersion with a TCS@ZIF-8 nanoparticle concentration of 1~5 mg / mL. C) Add the dispersion from step B) to the poly-ε-caprolactone spinning solution from step A), and stir until homogeneous to obtain the final product; The upper layer of the fiber membrane is obtained by spinning a spinning solution made from poly(ε-caprolactone), polyethylene glycol, and bromothymol blue. The preparation method of the spinning solution includes the following steps: i) Poly(ε-caprolactone) and polyethylene glycol are dissolved in a solvent to obtain a mixed spinning solution in which the concentration of poly(ε-caprolactone) is 5-10 wt% and the concentration of polyethylene glycol is 5-10 wt%. ii) Dissolve bromothymol blue in a solvent to obtain a bromothymol blue solution with a concentration of 10~20 mg / mL; iii) Add the bromothymol blue solution from step ii) to the mixed spinning solution from step i), and stir until homogeneous to obtain the final product; The TCS@ZIF-8 nanoparticles were prepared from the following raw materials in the following weight ratios: 1-5 parts zinc nitrate hexahydrate, 1-5 parts triclosan, and 1-5 parts 2-methylimidazole.

2. The functional fiber membrane according to claim 1, characterized in that: The TCS@ZIF-8 nanoparticles were prepared from the following raw materials in the following weight ratio: 1.5 parts zinc nitrate hexahydrate, 1 part triclosan, and 3.3 parts 2-methylimidazole.

3. The functional fiber membrane according to claim 1 or 2, characterized in that: The preparation method of the TCS@ZIF-8 nanoparticles includes the following steps: (1) Dissolve zinc nitrate hexahydrate in a solvent; (2) Dissolve 2-methylimidazole in a solvent; (3) Add triclosan to the solution obtained in step (1), then add the solution obtained in step (2), stir, centrifuge and dry to obtain TCS@ZIF-8 nanoparticles.

4. The functional fiber membrane according to claim 3, characterized in that: In step (1), the solvent is methanol or water; And / or, in step (2), the solvent is methanol or water.

5. The functional fiber membrane according to claim 1, characterized in that: In step A), the solvent is hexafluoroisopropanol, N,N-dimethylformamide, or N,N-dimethylacetamide; And / or, in step A), the concentration of the poly-ε-caprolactone is 8 wt%; And / or, in step B), the solvent is ethanol; And / or, in step B), the concentration of the TCS@ZIF-8 nanoparticles is 2 mg / mL; And / or, in step C), the volume-to-mass ratio of the dispersion in step B) to the poly(ε-caprolactone) spinning solution in step A) is 1 ml: 20 g.

6. The functional fiber membrane according to claim 1, characterized in that: In step i), the solvent is hexafluoroisopropanol, N,N-dimethylformamide, or N,N-dimethylacetamide; And / or, in step i), the concentration of poly(ε-caprolactone) is 7.4 wt%, and the concentration of polyethylene glycol is 7.4 wt%. And / or, in step ii), the solvent is ethanol; And / or, in step ii), the concentration of the bromothymol blue solution is 12 mg / mL; And / or, in step iii), the volume-to-mass ratio of the bromothymol blue solution in step ii) to the mixed spinning solution in step i) is 1 ml: 20 g.

7. The functional fiber membrane according to claim 1, characterized in that: The lower layer of the fiber membrane is spun by electrospinning. The electrospinning parameters are as follows: positive voltage: 10-15kV, negative voltage: 0.5-1kV, working distance between needle tip and current collector: 8-15 cm, extrusion speed: 0.5-1.5mL / h, and spinning time: 1.5-3h.

8. The functional fiber membrane according to claim 7, characterized in that: The electrospinning parameters are: positive voltage 14kV, negative voltage 0.5kV, working distance between needle tip and current collector 10 cm, extrusion speed 1.0 mL / h, and spinning time 2h.

9. The functional fiber membrane according to claim 1, characterized in that: The upper layer of the fiber membrane is spun by electrospinning. The electrospinning parameters are as follows: positive voltage: 10-15kV, negative voltage: 0.5-1kV, working distance between needle tip and current collector: 8-15 cm, extrusion speed: 0.5-1.5mL / h, and spinning time: 3-6h.

10. The functional fiber membrane according to claim 9, characterized in that: The electrospinning parameters are: positive voltage 14kV, negative voltage 0.5kV, working distance between needle tip and current collector 10 cm, extrusion speed 1.0 mL / h, and spinning time 4h.

11. A method for preparing the functional fiber membrane according to any one of claims 1 to 10, characterized in that: It includes the following steps: (a) After preparing a spinning solution using TCS@ZIF-8 nanoparticles and poly(ε-caprolactone) as raw materials, the lower layer of the fiber membrane is obtained by spinning. (b) After preparing a spinning solution using poly(ε-caprolactone), polyethylene glycol and bromothymol blue as raw materials, the solution is spun on the lower membrane to obtain a double-layer fiber membrane, which is the functional fiber membrane.

12. Use of the functional fiber membrane according to any one of claims 1 to 10 in the preparation of materials and / or devices for visual monitoring of bacteria and / or antibacterial activity.

13. The use according to claim 12, characterized in that: The bacteria are Escherichia coli, Staphylococcus aureus, and / or Candida albicans.

Images