Manufacturing and application of hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor

Abstract

The invention discloses a hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor and an application of the hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor in rapid detection of bacteria. According to the sensor, silver nanoparticles are prepared through a sodium citrate reduction method, a two-dimensional material MXene and a bimetal organic framework are combined, and a surface enhanced Raman scattering spectrum detection platform with high sensitivity, stability and anti-interference performance is constructed. The conductive network of MXene and the local surface plasmon resonance effect of silver nanoparticles synergistically enhance an electromagnetic field, and the porous structure of Fe-Co MOF enriches target molecules and forms dense hot spots, so that the Raman signal intensity is remarkably improved. Experiments show that the detection limit of the sensor to 4-mercaptobenzoic acid is as low as 10 <-12 > M, and the signal stability can last for 7 days; the detection limit on common pathogenic bacteria such as escherichia coli and staphylococcus aureus reaches 10 CFU / mL, and the linear correlation coefficient is superior to 0.96. The sensor has hydrophobicity and biocompatibility, can efficiently capture bacteria through capillary force, is suitable for trace detection of complex samples, and provides a new strategy for rapid diagnosis of clinical drug-resistant bacteria.

Description

Technical Field

[0001] This application is directed to the field of Raman scattering. Specifically, a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor is designed and applied to the rapid detection of bacteria. Background Art

[0002] Bacteria spread resistance genes across species through plasmids, integrons, and transposons, leading to a continued increase in multidrug resistance. Resistance mechanisms also widely exist among bacterial species, such as biofilm formation that impedes antibiotic penetration, efflux pumps that actively excrete drugs to reduce intracellular concentrations, and the production of target-inactivating enzymes that specifically degrade drugs.

[0003] Therefore, rapid and accurate detection technology is an important means to protect humans from bacterial harm, and clinical treatment and public health have an urgent need for it. However, for bacterial detection, existing methods have some unavoidable difficulties. Traditional bacterial culture methods were once considered the most accurate identification method, but they have certain limitations due to their lengthy cycle, insufficient sensitivity, and complex operation. Although PCR technology has shortened the detection cycle to 2-4 hours, its primer design relies on the characteristics of known gene sequences, resulting in the omission of new / mutated pathogens. At the same time, the risk of false positives and the lack of functional information further restrict its clinical value. Whole genome sequencing technology can deeply explore the mechanism of drug resistance by directly analyzing drug-resistant genes, but the high false positive rate of 15%-30% and the high cost seriously limit its popularization.

[0004] Surface-enhanced Raman scattering (SERS) couples light to the collective oscillations of free electrons on the surface of nanostructured noble metals, called surface plasmons, enabling detection at the single-molecule level. Compared to other detection methods, SERS is fast, accurate, has a high detection limit, is non-destructive, and provides in-situ detection capabilities. In recent years, the application of SERS in the detection of various bacterial species has become a new trend. By studying the structure, compositional characteristics, and spectral differences of bacteria, the differences between different bacterial species can be understood and identified. However, it is worth noting that the SERS detection method also has some shortcomings, mainly reflected in the high requirements for the reproducibility, stability, and sensitivity of the SERS sensor.

[0005] Therefore, to address the shortcomings of bacterial detection capabilities, we envision improving surface-enhanced Raman scattering (SERS) detection capabilities from two perspectives. We believe that SERS sensors should possess excellent physicochemical affinity and biocompatibility, attracting bacteria in aqueous environments and generating a strong SERS signal in a stable and uniform manner within the local electric field. Furthermore, the sensor should be sufficiently hydrophobic to attract bacteria from the solution and maximize capillary forces to pin the bacteria within the "hotspot" region. Furthermore, the non-planar structure should establish a three-dimensional plasmon region, allowing bacteria to be excited by free electrons and scattered light at multiple levels, enhancing SERS detection capabilities and providing a promising method and approach for bacterial detection. Summary of the Invention

[0006] The present invention reduces silver nanoparticles with sodium citrate and silver nitrate, mixes and stirs with MXene to incubate Ag / MXene, synthesizes Fe-Co MOF with cobalt chloride hexahydrate and anhydrous ferric chloride combined with 2-aminoterephthalic acid, and adds n-hexane to synthesize DD-PDMS. Ag / MXene and Fe-Co MOF are stacked on DD-PDMS in sequence to synthesize a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor, which can enhance the Raman signal, provide a high surface-enhanced Raman scattering enhancement factor, and has the advantages of high stability, strong anti-interference, and high plasmon effect.

[0007] The present invention first prepares silver nanoparticles. Due to the presence of sodium citrate, Ag + Not only is it reduced to Ag 0 Nanoparticles can also be adsorbed on the particle surface through carboxylic acid groups, providing electrostatic stabilization and preventing agglomeration. This eliminates the need for additional stabilizers and simplifies subsequent purification steps. Furthermore, boiling and refluxing accelerate the reaction, improve reduction efficiency, and promote the formation of smaller, more monodisperse silver nanoparticles. Compared to larger, uncontrollable synthesis methods, the silver nanoparticles synthesized by this method have significant stability and enhanced surface-enhanced Raman scattering.

[0008] To further protect the silver nanoparticles and enhance the overall conductivity of the sensor, MXene was synthesized using Ti3AlC2 as the raw material. This facilitates charge transfer, enhances the local electromagnetic field, and synergizes with the silver nanoparticles. It also slows down the oxidation and aggregation of the silver nanoparticles, extending the life of the surface-enhanced Raman scattering sensor. The hydrophilic functional groups on the surface facilitate the adsorption of polar molecules, greatly expanding the sensor's application range.

[0009] Furthermore, to further enhance the performance and reproducibility of surface-enhanced Raman scattering sensors, an Fe-Co MOF was synthesized. Its unique porous structure, bimetallic synergistic effect, and surface functional group modification significantly improve detection sensitivity and selectivity. The MOF's high surface area and nanoscale pores efficiently load silver nanoparticles and enrich the target molecules, forming dense electromagnetic field "hotspots" that amplify the Raman signal by 1-2 orders of magnitude. Furthermore, the Fe / Co bimetallic junctions facilitate charge transfer, and the amino groups of the NH2-BDC ligands enhance molecular adsorption, enabling the sensor to maintain excellent performance even in complex environments.

[0010] Finally, to enhance the adhesion of PDMS, we added n-hexane to form a new DD-PDMS. This PDMS significantly improves the mechanical strength of the substrate, provides more anchoring sites for microparticles, and, combined with the inherent hydrophobicity of PDMS, enables detection of complex samples. Subsequently, silver nanoparticles, MXene, and Fe-Co MOF were mixed in appropriate proportions, dripped onto the DD-PDMS, and dried to form a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] (1) 4 mL of sodium citrate solution (1%) was added to 200 mL of boiling silver nitrate solution (0.175 mg / mL). After continuous stirring and refluxing for 1 hour, a yellow-green silver nanoparticle solution was obtained. The solution was then centrifuged at 10,000 rpm for 5 minutes, and the supernatant was removed. This was repeated three times. Finally, the solution was placed in deionized water to obtain a silver nanoparticle dispersion, which was stored at 4°C until use.

[0013] (2) 6 g of lithium fluoride was mixed with 120 mL of 9 M hydrochloric acid solution and treated in an ultrasonic cleaner for 30 minutes to obtain a uniform dispersion system. 6 g of titanium aluminum carbide powder was then slowly added. The mixed solution was then centrifuged and dried in a vacuum environment. Next, 1 g of MXene material was mixed with 100 mL of deionized water and ultrasonically treated in an ice-water bath for 1 hour. Finally, after centrifugation at 4000 rpm for 1 hour, the upper gray-green solution was collected and stored at 4°C for later use.

[0014] (3) First, 1mM ferric chloride hexahydrate and 1mM cobalt chloride hexahydrate were dissolved in 7.5mL N,N-dimethylformamide. At the same time, 1mM 2-aminoterephthalic acid was dissolved in 7.5mL N,N-dimethylformamide. Then, NH2-BDC solution was slowly added to the above metal salt solution and reacted for 30 minutes under vigorous stirring. The mixed solution was transferred to a 100mL polytetrafluoroethylene autoclave and reacted at 120℃ for 24 hours. After the reaction was completed, the product was washed alternately with N,N-dimethylformamide and ethanol three times, and a brown solid product was obtained by centrifugation. Finally, the product was placed in a vacuum drying oven at 80℃ and dried for 12 hours to obtain the final product. The solid weight was weighed and diluted to 10mg / L with PBS solution to obtain a Fe-Co MOF dispersion.

[0015] (4) Sylgard 184 component A and component B were mixed in a beaker at a volume ratio of 10:1, followed by the addition of n-hexane (solvent: prepolymer volume ratio of 2:1) and magnetic stirring for 30 minutes. The mixture was transferred to a polytetrafluoroethylene container, sealed, and then placed in a hydrothermal reactor. The solution was heated and cured at 120°C for 2 hours. After cooling to room temperature, it was immersed in n-hexane several times to remove excess monomers. The transparent PDMS gel shrank after drying at room temperature, obtaining DD-PDMS as a substrate.

[0016] (5) The prepared silver nanoparticle dispersion was mixed with MXene (5%) solution in a ratio of 4:1 and stirred in the dark for 2 hours. 40 μL of the mixed solution was dropped on the PDMS surface, followed by 10 μL of Fe-Co MOF dispersion. The mixture was transferred to an oven and dried at 50 °C for 20 minutes to obtain a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor.

[0017] (6) The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor finally generated in step (5) was subjected to surface-enhanced Raman scattering activity detection, and trace amounts of 4-mercaptobenzoic acid, Escherichia coli, Enterococcus faecalis, Enterococcus hirae, Pseudomonas aeruginosa, and Staphylococcus aureus were measured.

[0018] Furthermore, the hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor is used in bacterial detection.

[0019] Based on the design and preparation of a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor, the present invention constructs a surface-enhanced Raman scattering detection strategy for accurate, sensitive, and highly specific detection of bacteria.

[0020] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor and its application in bacterial detection, which has the following beneficial effects:

[0021] (1) The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor has a high specific surface area, excellent charge transfer ability and strong local electromagnetic field enhancement effect. The two-dimensional conductive network of MXene works synergistically with the plasma resonance effect of silver nanoparticles, and the porous structure of Fe-Co MOF provides a molecular enrichment function. The present invention combines the three elements and applies them to the surface-enhanced Raman scattering detection platform, which can achieve highly sensitive, highly selective and highly stable trace detection of target analytes.

[0022] (2) The detection limit of 4-mercaptobenzoic acid of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor can reach 1.0×10 -12 M, the signal has a stable enhancement effect within 7 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. The embodiments shown in the drawings are only to help understand the present invention and do not constitute a limitation on the scope of protection.

[0024] Figure 1 The surface-enhanced Raman scattering spectra of 4-mercaptobenzoic acid detected by the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor were compared with those of the Ag / MXene sensor and the silver nanoparticle sensor, as well as the original spectrum of 4-mercaptobenzoic acid.

[0025] Figure 2 Surface-enhanced Raman scattering spectra of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor for detecting 4-mercaptobenzoic acid at different concentrations.

[0026] Figure 3 This is the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of 4-mercaptobenzoic acid.

[0027] Figure 4 This is a graph showing the relationship between the surface enhanced Raman scattering signal intensity and time.

[0028] Figure 5In order to explore the results of the surface-enhanced Raman scattering detection of Escherichia coli in the present invention: the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detects the surface-enhanced Raman scattering spectra of Escherichia coli with different concentrations.

[0029] Figure 6 In order to explore the results of the surface-enhanced Raman scattering detection of Escherichia coli in the present invention: the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of Escherichia coli.

[0030] Figure 7 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detects the surface-enhanced Raman scattering spectra of Enterococcus faecalis at different concentrations.

[0031] Figure 8 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of Enterococcus faecalis.

[0032] Figure 9 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detects the surface-enhanced Raman scattering spectra of Enterococcus hirsuta at different concentrations.

[0033] Figure 10 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of Enterococcus hirsuta.

[0034] Figure 11 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detects the surface-enhanced Raman scattering spectra of Pseudomonas aeruginosa at different concentrations.

[0035] Figure 12 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of Pseudomonas aeruginosa.

[0036] Figure 13In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detects the surface-enhanced Raman scattering spectra of Staphylococcus aureus with different concentrations.

[0037] Figure 14 In order to explore the results of the surface-enhanced Raman scattering detection of Enterococcus faecalis in the present invention: the concentration linear relationship diagram of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor detecting different concentrations of Staphylococcus aureus. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Example 1

[0040] Firstly, a silver nanoparticle dispersion was prepared by sodium citrate reduction method, and a titanium aluminum carbide precursor was etched with lithium fluoride / hydrochloric acid and ultrasonically exfoliated to obtain a MXene dispersion. At the same time, a Fe-Co MOF dispersion was synthesized by solvothermal method. Subsequently, a PDMS prepolymer was mixed with n-hexane and thermally cured to prepare a flexible substrate. Finally, a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor with excellent performance was successfully constructed by mixing silver nanoparticles and MXene solution in a 4:1 ratio and drop-coating it on a PDMS substrate. The Fe-Co MOF dispersion was then added and dried.

[0041] Example 2 Detection of Raman reporter molecule 4-mercaptobenzoic acid based on hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor

[0042] The present invention was used to conduct a validation study on the Raman reporter molecule 4-mercaptobenzoic acid. Figure 1 As shown in the figure, the surface-enhanced Raman scattering marker molecule 4-mercaptobenzoic acid was detected on sensors loaded with different surface-enhanced Raman scattering substrates, and the signal intensity comparison of the hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor compared with other sensors was obtained. The enhancement factor EF was calculated to be 3.4902×10 6 . Figure 2 , 3 different concentrations of 4-mercaptobenzoic acid were detected by surface enhanced Raman scattering, and the hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor was obtained to detect different concentrations (10-5 M, 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, 10 -12 M) Surface enhanced Raman scattering spectrum of 4-mercaptobenzoic acid and its linear relationship with concentration, R 2 The prepared hybrid Ag / MXene / Fe-CoMOF surface enhanced Raman scattering sensor was placed in a room temperature environment and tested once every 24 hours after the first test, and the obtained Figure 4 A plot of the surface-enhanced Raman scattering signal intensity versus time, demonstrating its stability.

[0043] Example 3 Detection of bacteria based on hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor

[0044] The application of the present invention to bacteria has been studied.

[0045] Figure 5 Hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor detects different concentrations (10 6 CFU / mL, 10 5 CFU / mL, 10 4 CFU / mL, 10 3 CFU / mL, 10 2 CFU / mL, 10 CFU / mL,) surface enhanced Raman scattering spectra of Escherichia coli ( Figure 6 ) and concentration, and calculated R 2 It is 0.976.

[0046] Figure 7 Hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor detects different concentrations (10 6 CFU / mL, 10 5 CFU / mL, 10 4 CFU / mL, 10 3 CFU / mL, 10 2 CFU / mL, 10 CFU / mL,) Surface enhanced Raman scattering spectra of Enterococcus faecalis ( Figure 8 ) and concentration, and calculated R 2 is 0.996.

[0047] Figure 9Hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor detects different concentrations (10 6 CFU / mL, 10 5 CFU / mL, 10 4 CFU / mL, 10 3 CFU / mL, 10 2 CFU / mL, 10 CFU / mL,) Surface enhanced Raman scattering spectra of Enterococcus hirae ( Figure 10 ) and concentration, and calculated R 2 It is 0.882.

[0048] Figure 11 Hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor detects different concentrations (10 6 CFU / mL, 10 5 CFU / mL, 10 4 CFU / mL, 10 3 CFU / mL, 10 2 CFU / mL, 10 CFU / mL,) Surface enhanced Raman scattering spectra of Pseudomonas aeruginosa ( Figure 12 ) and concentration, and calculated R 2 is 0.98.

[0049] Figure 13 Hybrid Ag / MXene / Fe-Co MOF surface enhanced Raman scattering sensor detects different concentrations (10 6 CFU / mL, 10 5 CFU / mL, 10 4 CFU / mL, 10 3 CFU / mL, 10 2 CFU / mL, 10 CFU / mL,) surface enhanced Raman scattering spectra of Staphylococcus aureus ( Figure 14 ) and concentration, and calculated R 2 It is 0.967.

[0050] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor, characterized in that: include: PDMS film, Fe-Co MOF, silver nanoparticles and MXene; Ag / MXene / Fe-Co MOF solution is added dropwise on the PDMS film to inhibit the oxidation of silver nanoparticles, enhance conductivity, surface-enhanced Raman scattering signal intensity, and immobilize target analytes.

2. The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor according to claim 1, characterized in that: PDMS film is a flexible transparent film that can be adhered to uneven surfaces.

3. The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor according to claim 1, characterized in that: MXene is completely spread on the film, and the enhancement of MXene comes not only from electromagnetic enhancement, but also contributes to chemical enhancement.

4. The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor according to claim 1, characterized in that Fe-Co MOF is deposited on MXene with a diameter of 300-600 nm and exhibits excellent electromagnetic enhancement.

5. A method for preparing a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor, characterized in that: The steps include: (1) 4 mL of sodium citrate solution (1%) was added to 200 mL of boiling silver nitrate solution (0.175 mg / mL). After continuous stirring and refluxing for 1 hour, a yellow-green silver nanoparticle solution was obtained. The solution was then centrifuged at 10,000 rpm for 5 minutes, and the supernatant was removed. This was repeated three times. Finally, the solution was placed in deionized water to obtain a silver nanoparticle dispersion, which was stored at 4°C until use. (2) 6 g of lithium fluoride was mixed with 120 mL of 9 M hydrochloric acid solution and treated in an ultrasonic cleaner for 30 minutes to obtain a uniform dispersion system. 6 g of titanium aluminum carbide powder was then slowly added. The mixed solution was then centrifuged and dried in a vacuum environment. Next, 1 g of MXene material was mixed with 100 mL of deionized water and ultrasonically treated in an ice-water bath for 1 hour. Finally, after centrifugation at 4000 rpm for 1 hour, the upper gray-green solution was collected and stored at 4°C for later use. (3) First, 1mM ferric chloride hexahydrate and 1mM cobalt chloride hexahydrate were dissolved in 7.5mL N,N-dimethylformamide. At the same time, 1mM 2-aminoterephthalic acid was dissolved in 7.5mL N,N-dimethylformamide. Then, NH2-BDC solution was slowly added to the above metal salt solution and reacted for 30 minutes under vigorous stirring. The mixed solution was transferred to a 100mL polytetrafluoroethylene autoclave and reacted at 120℃ for 24 hours. After the reaction was completed, the product was washed alternately with N,N-dimethylformamide and ethanol three times, and a brown solid product was obtained by centrifugation. Finally, the product was placed in a vacuum drying oven at 80℃ and dried for 12 hours to obtain the final product. The solid weight was weighed and diluted to 10mg / L with PBS solution to obtain a Fe-CoMOF dispersion. (4) Sylgard 184 component A and component B were mixed in a beaker at a volume ratio of 10:1, followed by the addition of n-hexane (solvent: prepolymer volume ratio of 2:1) and magnetic stirring for 30 minutes. The mixture was transferred to a polytetrafluoroethylene container, sealed, and then placed in a hydrothermal reactor. The solution was heated and cured at 120°C for 2 hours. After cooling to room temperature, it was immersed in n-hexane several times to remove excess monomers. The transparent PDMS gel shrank after drying at room temperature, obtaining DD-PDMS as a substrate. (5) The prepared silver nanoparticle dispersion was mixed with MXene (5%) solution in a ratio of 4:1 and stirred in the dark for 2 hours. 40 μL of the mixed solution was dropped on the PDMS surface, followed by 10 μL of Fe-Co MOF dispersion. The mixture was transferred to an oven and dried at 50 °C for 20 minutes to obtain a hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor. (6) The hybrid Ag / MXene / Fe-Co MOF surface-enhanced Raman scattering sensor finally generated in step (5) was subjected to surface-enhanced Raman scattering activity detection, and trace amounts of 4-mercaptobenzoic acid, Escherichia coli, Enterococcus faecalis, Enterococcus hirae, Pseudomonas aeruginosa, and Staphylococcus aureus were measured.

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