Light-triggered AuAg-coated g-C3N4 composite nano platform and application thereof in multi-mode broad-spectrum sterilization

Abstract

The invention belongs to the technical field of synthesis and application of nano materials, and particularly relates to a light-triggered AuAg-coated g-C3N4 composite nano platform and application thereof in multi-mode broad-spectrum sterilizing.AuAg core-shell metal nanoparticles synthesized with ginger essential oil as a reducing agent are physically mixed and anchored to the surface of a g-C3N4 layer, the light-triggered AuAg-coated g-C3N4 composite nano platform is constructed, and the light-triggered AuAg-coated g-C3N4 composite nano platform is applied to multi-mode broad-spectrum sterilizing.The light-triggered AuAg-coated g-C3N4 composite nano platform is prepared. The platform can be used for efficient sterilization treatment and has excellent broad-spectrum synergistic antibacterial performance on escherichia coli, staphylococcus aureus, pseudomonas aeruginosa and bacillus subtilis, the sterilization efficiency reaches up to 100%, and the composite nano platform can play broad-spectrum disinfection and anti-inflammation functions and has good application prospects. The novel strategy can be used for treating chronic wound bacterial infection related diseases in the future, and a new research direction is provided for developing a multi-mode synergistic sterilization composite nano platform.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterial synthesis and application, and specifically relates to a light-triggered AuAg@g-C3N4 composite nano-platform and its application in multi-mode broad-spectrum sterilization. Background Art

[0002] Due to the extensive use of antibiotics in recent decades and the increase in bacterial strains that are resistant to antibiotics, the effectiveness of traditional antibiotic therapy has become increasingly poor. In the field of antimicrobial agents, the emergence of nanomaterials with unique physical and chemical properties is expected to provide an alternative to antibiotics and improve the effectiveness of bactericidal therapy. The bactericidal pathways of nanomaterials mainly include the following three aspects: (1) Destroying bacterial cell membranes. The controllability of the size, surface chemical properties and shape of nanomaterials enables them to directly pierce the cell wall and cell membrane of bacteria like a "nano scalpel", causing nanoperforation and completing extremely effective antibacterial treatment; (2) Oxidative damage or photothermal therapy. Nanomaterials with enzyme-like activity or photothermal conductivity can produce oxidative stress or thermal effects, destroying internal components of bacteria and affecting bacterial differentiation, signal transduction, survival and apoptosis; (3) Loading bactericidal drugs. In order to identify target genes and achieve precise treatment, nanomaterials can be used as carriers to load antimicrobial peptides with gene silencing function into bacteria. In order to further improve the antibacterial efficiency, people have successively developed strategies combining reactive oxygen species damage (ROS) with photothermal therapy (PTT). The synergistic bactericidal therapeutic effect produced by photocatalytic nanocomposites is expected to be applied in the following aspects.

[0003] Essential oils (EOs) are volatile aromatic substances extracted from different parts of plants. In recent years, different essential oils have been increasingly used as ideal alternatives to chemical preservatives due to their excellent antibacterial properties. Among them, ginger essential oil (GEO) extracted from the root of ginger has received extensive research attention. These studies focus on the antioxidant, antifungal and antibacterial properties of ginger essential oil and its increasingly wide application in food preservation. For example, nanocapsules based on ginger essential oil have significant antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Recent studies have found that doping with transition metals, developing heterojunction structures and depositing metal-based nanoparticles can effectively solve the relatively narrow photoresponse range of graphene nitride (g-C3N4) and the high recombination rate of photogenerated electron-hole pairs, thereby synthesizing nano-bactericidal complexes with good thermal and chemical stability. Therefore, combined with the excellent antibacterial properties of GEO, the nanocomplex antibacterial materials formed by doping nanoparticles with GEO as a reducing agent and doping g-C3N4 have more outstanding antibacterial potential. Summary of the invention

[0004] The present invention solves the above-mentioned technical problems existing in the prior art, provides a light-triggered AuAg@g-C3N4 composite nano-platform and applies the platform to the broad-spectrum synergistic antibacterial effect against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis.

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

[0006] A method for constructing a light-triggered AuAg@g-C3N4 composite nanoplatform comprises the following steps:

[0007] The aqueous solution of AuAg core-shell metal nanomaterials was mixed with g-C3N4 to prepare the AuAg@g-C3N4 composite nanoplatform;

[0008] The surface of the AuAg core-shell metal nanomaterial is loaded with ginger essential oil.

[0009] Preferably, the aqueous solution of the AuAg core-shell metal nanomaterial is heated to 80-100° C., mixed with g-C3N4, and the reaction is continued for 1-3 hours; preferably, the reaction temperature is 100° C. and the reaction time is 2 hours.

[0010] Preferably, the concentration of the aqueous solution of the AuAg core-shell metal nanomaterial is 37.5×10 -3 mM, the molar ratio of the AuAg core-shell metal nanomaterial to g-C3N4 is 1.5×10 -6 .

[0011] Preferably, the preparation method of the AuAg core-shell metal nanomaterial is: using chloroauric acid aqueous solution and silver nitrate aqueous solution as raw materials and ginger essential oil as a reducing agent to prepare the AuAg core-shell metal nanomaterial.

[0012] Preferably, in the reaction system, the concentration of the chloroauric acid aqueous solution is 10-30 mM; the concentration of the silver nitrate aqueous solution is 10-30 mM; the mass fraction of the ginger essential oil is 0.05-0.15 g / mL, preferably 0.1 g / mL; the reaction temperature is 60-80°C, preferably 70°C; and the reaction time is 1-5 min, preferably 2 min.

[0013] Preferably, the ginger essential oil is extracted from fresh ginger as raw material.

[0014] Preferably, the preparation method of g-C3N4 is: using urea as raw material and calcining it at a constant temperature in an air atmosphere; the constant temperature calcination temperature can be selected from 200 to 600°C, preferably 550°C; the reaction time is 1-4h, preferably 3h.

[0015] The present invention also provides the AuAg@g-C3N4 composite nano-platform prepared by the above method.

[0016] The present invention also provides the application of the AuAg@g-C3N4 composite nano-platform in multi-mode broad-spectrum sterilization, which can be used to prepare sterilization materials, sterilization drug preparations, sterilization medical devices, etc., and can be used to efficiently and synergistically kill broad-spectrum bacteria such as Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa.

[0017] The beneficial effects of the light-triggered AuAg@g-C3N4 composite nano-platform provided by the present invention in the study of broad-spectrum synergistic antibacterial performance are:

[0018] (1) Doping with transition metals, developing heterojunction structures, and depositing metal-based nanoparticles can effectively solve the relatively narrow photoresponse range of graphene nitride (g-C3N4) and the high recombination rate of photogenerated electron-hole pairs, thereby synthesizing nano-bactericidal complexes with good thermal and chemical stability.

[0019] (2) Ginger essential oil (GEO) is used as a reducing agent to replace traditional chemical reagents, which is more environmentally friendly and safe, with low cost and simple extraction operation.

[0020] (3) The constructed composite nanoplatform has a lower band gap and higher visible light utilization efficiency, which can better promote free electron transfer and exhibit better photocatalytic activity under light conditions.

[0021] (4) The resulting multi-mode synergistic antibacterial bactericidal system has excellent broad-spectrum synergistic antibacterial properties against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis, with a bactericidal efficiency of up to 100%. This provides a new research direction for the development of a composite nano-platform with multi-mode synergistic antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Characterization of the AuAg@g-C3N4 composite nanoplatform and its constituent units. (a) Schematic diagram of the light-triggered AuAg@g-C3N4 composite nanoplatform to generate ROS. TEM images of AuNPs (b), AgNPs (c), AuAg (d), g-C3N4 (e), Au@g-C3N4 (f), Ag@g-C3N4 (g), and AuAg@g-C3N4 (h). i) UV-visible spectra of AuNPs, AgNPs, and AuAg. j) UV-visible spectra of g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4. k) Tauc plots of g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4.

[0023] Figure 2(a) TEM image of 1 mM AuAg@g-C3N4 showing uniform presence of AuAg on g-C3N4 flakes. (b) HR-TEM image of the boundaries between smaller and spherical AuAg on g-C3N4. (c) Selected area of ​​drift correlation spectroscopy used to draw elemental maps. C element map (orange), N element map (green), Au element map (yellow), and Ag element map (purple). (d) Elemental composition of AuAg@g-C3N4.

[0024] Figure 3 (a) Zeta potential of AuNPs, AgNPs, and AuAg. (b) Representative XRD patterns of g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4.

[0025] Figure 4 Figure 2 is the in vitro antibacterial evaluation of the multimodal synergistic nanoplatform. (a) ROS generation levels of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa after incubation with AuNPs, AgNPs, AuAg, g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4. (b) Continuous release curves at 3h, 6h, 9h, 12h, 24h, 36h, and 48h (inside and outside bacteria). (c) SEM images of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa incubated with the AuAg@g-C3N4 composite nanoplatform and light irradiation for 5 min, respectively.

[0026] Figure 5 Colony photos of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa by light-triggered or non-triggered AuNPs, AgNPs, AuAg, g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4 composite nanoplatforms.

[0027] Figure 6 The survival rates of different bacteria after using different concentrations of AuAg@g-C3N4 composite nanoplatforms, (a) Escherichia coli, (b) Staphylococcus aureus, (c) Bacillus subtilis and d) Pseudomonas aeruginosa.

[0028] Figure 7 It is a cell compatibility experiment of the composite material. (a) Cytotoxicity of GEO, AuNPs, AgNPs, AuAg, g-C3N4, Au@g-C3N4, Ag@g-C3N4, AuAg@g-C3N4 under 20mg / L conditions. (b) Cell viability of AuAg@g-C3N4 under 10mg / L-60mg / L conditions. DETAILED DESCRIPTION

[0029] Embodiment 1:

[0030] The target bacteria in this embodiment are Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa.

[0031] The light-triggered AuAg@g-C3N4 composite nanoplatform is used for a multi-mode broad-spectrum bactericidal treatment method, which comprises the following steps:

[0032] (1) Fresh ginger essential oil (GEO) was extracted from ginger roots and AuNPs, AgNCs, and AuAg core-shell metal nanoparticles were prepared by reduction method.

[0033] (2) Nanosheet g-C3N4 was prepared and combined with AuNPs, AgNCs and AuAg core-shell metal nanoparticles to synthesize Au@g-C3N4, Ag@g-C3N4 and AuAg@g-C3N4.

[0034] (3) Light-triggered Ag synthesis of AuAg@g-C3N4 composite nanomaterials + Sustained release experiment.

[0035] (4) Test of antibacterial properties of light-triggered AuAg@g-C3N4 composite nanoplatform.

[0036] (5) Study on the antibacterial mechanism of light-triggered AuAg@g-C3N4 composite nanoplatform.

[0037] (6) Study on the cell compatibility of light-triggered AuAg@g-C3N4 composite nanomaterials.

[0038] The preparation method of AuNPs, AgNPs and AuAg core-shell metal nanoparticles in step (1) is as follows:

[0039] Fresh ginger (20 g) was washed, left overnight, peeled, crushed, and added to a 250 mL volumetric flask. 200 mL of ultrapure water was added to the volumetric flask, distilled under normal pressure, and the filtered solution was ginger essential oil (GEO).

[0040] Add 1.5mL of fresh ginger essential oil to a centrifuge tube and place it in a 70℃ water bath. Then, add 80uL of 1% HAuCl4 to the above centrifuge tube and react for 2min to obtain a purple-red solution, proving that AuNPs have been synthesized. In the reaction system, the concentration of chloroauric acid aqueous solution is 10-30mM, the mass fraction of ginger essential oil is 0.05-0.15g / mL, the reaction temperature is 60-80℃, and the reaction time is 1-5min. A purple-red solution can be obtained to synthesize AuNPs.

[0041] Put 1.5mL of fresh ginger essential oil into a centrifuge tube and place it in a 75℃ water bath. Then take 35uL of 1% AgNO3 and add it to the centrifuge tube. React for 2min to obtain a brown solution for synthesizing AgNPs. In the reaction system, the concentration of silver nitrate aqueous solution is 10-30mM, the mass fraction of ginger essential oil is 0.05-0.15g / mL, the reaction temperature is 60-80℃, and the reaction time is 1-5min. A brown solution can be obtained to synthesize AgNPs.

[0042] Take 1.5mL ginger essential oil and put it into a centrifuge tube, and place it in a 70℃ water bath. Then take 60uL of 1% HAuCl4 and add it into the above centrifuge tube. After the color of the tube changes, immediately add 25uL of 1% AgNO3 and react for 2min to obtain a reddish brown solution to synthesize AuAg core-shell metal nanoparticles. In the reaction system, the concentration of chloroauric acid aqueous solution is 10-30mM, the concentration of silver nitrate aqueous solution is 10-30mM, the mass fraction of ginger essential oil is 0.05-0.15g / mL, the reaction temperature is 60-80℃, and the reaction time is 1-5min. A reddish brown solution can be obtained to synthesize AuAg core-shell metal nanoparticles.

[0043] The preparation method of the nano-sheet g-C3N4 and Au@g-C3N4, Ag@g-C3N4 and AuAg@g-C3N4 in step (2) is as follows:

[0044] 10g of urea was placed in a crucible, and then transferred to a muffle furnace and heated at 550℃ at a rate of 10℃ / min for 3h. At the end of the reaction, a light yellow solid powder g-C3N4 was obtained. Then the prepared AuNPs (1.58mL, 50nM), AgNPs (1.535mL, 102.8ug / mL) and AuAg (1.585mL, 37.5nM) were heated to boiling, g-C3N4 powder (5mg) was added and stirred for 2h, and finally centrifuged, washed and dried to obtain a composite material (Au@g-C3N4, Ag@g-C3N4, AuAg@g-C3N4). The constant temperature calcination temperature can be selected from 200 to 600℃, and the reaction time is 1-4h, and a light yellow solid powder g-C3N4 can be obtained.

[0045] In the step (3), the Ag of the light-triggered AuAg@g-C3N4 composite nanomaterial + The experimental method of sustained-release experiment is as follows:

[0046] AuAg@g-C3N4 was dispersed in a solution with a final concentration of 0.1 mg ml -1The samples were then incubated with shaking at 30 °C for 1, 3, 5, and 7 days before being sampled for ICP measurement.

[0047] The method for testing the antibacterial performance of light-triggered AuAg@g-C3N4 in step (4) is as follows:

[0048] Antibacterial experiments were conducted on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. First, the four bacteria were gradiently diluted with nutrient broth to select the bacterial concentration required for subsequent experiments (105-107 CFU mL -1 ). 100μL GEO, 100μL 2mMAuNPs, 100μL 2mMAgNPs, 100μL 2mMAuAg, 50mg / L g-C3N4, 50mg / LAu@g-C3N4, 50mg / LAg@g-C3N4, 50mg / LAuAg@g-C3N4 and different bacteria were incubated for 12h in a constant temperature shaker (37℃, 220rpm) under light (or dark) conditions. Then, 100μL of the bacterial suspension after reaction with different substances was taken, dropped onto the LB agar plate with a pipette, and evenly spread on the LB agar plate with a sterilized coating tool, incubated at 37℃ overnight, and the number of colonies on the agar plate was observed. The group without any material was used as a blank control.

[0049] Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The minimum inhibitory concentration (MIC) is the concentration value of the corresponding substance when the bacterial growth curve is parallel to the time axis. The minimum bactericidal concentration (MBC) refers to the concentration value of the corresponding substance when the bacterial growth curve is close to zero. First, the composite material was mixed with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis, and incubated for 12h (37°C, 220rpm). Then, 100 μL of the above mixture was added to a 96-well plate containing LB medium, placed on a constant temperature oscillator for stirring, and a UV-visible spectrophotometer was used at 600nm (OD 600 ) and the absorbance of the bacterial suspension was measured and the experiment was repeated 3 times.

[0050] The research method of the antibacterial mechanism of the light-triggered AuAg@g-C3N4 composite nano-platform in step (5) is as follows:

[0051] Reactive oxygen species (ROS) were determined using an active oxygen species determination kit. First, DCFH-DA was diluted to 10 μM with serum-free medium at 1:1000, and then 10 mL of LB solution containing Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis were added, respectively, and incubated at 37 ° C and 220 rpm for 20 min, stirring every 5 min to ensure that the bacteria and DCFH-DA were fully mixed. Finally, the bacteria were collected and washed three times with PBS. The collected bacterial suspension was added to PBS containing different materials and incubated with different materials for 12 h. The bacteria were collected by centrifugation (5000 rpm, 5 min) and transferred to a 96-well plate, at which time the fluorescence intensity of DCFH was measured. The excitation wavelength was 488 nm and the emission wavelength was 525 nm.

[0052] Cell morphology observation. In order to prepare SEM samples, suspensions of several bacteria were incubated with AuAg@g-C3N4 materials for 12 hours, and then the bacteria were collected by centrifugation (5000rpm, 5min). 2.5% glutaraldehyde fixative was added to the bacterial precipitate and fixed overnight at 4°C. The next day, it was washed three times with 0.9% NaCl solution and then dehydrated under a gradient of ethanol concentrations (25%, 50%, 75%, 90%, 100%). Finally, the obtained bacterial precipitate was suspended in 100% ethanol solution, 10 μL of the suspension was taken with a pipette, and dried on conductive glass (ITO) to obtain a SEM sample.

[0053] Intracellular and extracellular silver ion release test. First, 25 mg AuAg@g-C3N4 was added to a medium containing 100 mL LB, and 100 μL E. coli suspension was added, and the mixture was incubated at 37 °C in a shaker. After incubation for 3, 6, 9, 12, 24, 36, and 48 h, 5 mL of the sample solution was taken, and 5 mL of fresh LB medium was added again. The supernatant was centrifuged at 10,000 rpm for 10 min, and the Ag in the solution was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). + concentration.

[0054] The E. coli precipitate was extracted from the above solution and nitrated. The resulting solution was filtered through a 0.22 μm membrane and the Ag in the bacteria was determined by ICP-OES. + concentration.

[0055] The method for studying the cell compatibility of the light-triggered AuAg@g-C3N4 composite nanomaterial in step (6) is as follows:

[0056] L929 and Raw264.7 cells were seeded in 96-well plates (1×104 cells / well, 100 μL). After incubation for 24 h, the plates were washed three times with PBS. After adding 100 μL of fresh culture medium (0, 1, 2, 5, 10, 20, 25, 30, 40, 50 μg / mL) with different concentrations of AuAg@g-C3N4 (0, 1, 2, 5, 10, 20, 25, 30, 40, 50 μg / mL) for 2 h, the old culture medium was discarded, the plates were washed 3 times with PBS, 100 μL of 5 mg / mL MTT solution (culture medium solubilization) was added to each well and incubated for 4 h. The PBS group was the negative control group. The MTT solution was taken, washed 3 times with PBS, 150 μL of DMSO solution was added to each well, incubated for 4 h, and the absorbance value at 570 nm was detected with an enzyme marker.

[0057] The specific test results are as follows:

[0058] (1) Structure and morphology characterization of AuNPs, AgNPs, AuAg, g-C3N4, AAu@g-C3N4, Ag@g-C3N4 and AuAg@g-C3N4:

[0059] like Figure 1 As shown in the transmission electron microscopy (TEM) images and dynamic light scattering (DLS), AuNPs ( Figure 1 b) AgNPs( Figure 1 c) and AuAg( Figure 1 d) showed excellent dispersion and uniformity in morphology and size, with the final average diameters being approximately 16 nm, 50 nm, and 20 nm, respectively. From these data, it can be inferred that the silver shell is grown on the surface of AuNPs. Next, TEM was used to examine the prepared sample g-C3N4 ( Figure 1 e) Au@g-C3N4( Figure 1 f), Ag@g-C3N4( Figure 1 g) and AuAg@g-C3N4( Figure 1 h) Conduct surface analysis, morphology analysis, particle shape analysis and particle size analysis. Figure 1 f. Figure 1 g and Figure 1 h, the black dots with shaded colors represent AuNPs, AgNPs, and AuAg, respectively, and the flake-like gray area corresponds to the flake-like morphology of the polymer g-C3N4. The UV-visible diffuse reflectance spectra of g-C3N4, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4 are shown in Figure 1i and 1j. The UV absorption peaks of AuNPs, AgNPs and AuAg are 530nm, 410nm and 475nm, respectively. The absorption edge of g-C3N4 is around 450nm, generally starting from its band gap value of 2.375eV. Therefore, the gradual decrease in the band gap values ​​of Au@g-C3N4, Ag@g-C3N4 and AuAg@g-C3N4 composite structures clearly indicates the localized surface plasmon resonance (LSPR) effect of AuNPs, AgNPs and AuAg. Whenever the plasmon effect leads to increased energy absorption, the wavelength will be blue-shifted, and the higher absorption value confirms the successful decoration of AuNPs, AgNPs and AuAg on the surface of g-C3N4 sheets.

[0060] (2) HR-TEM, EDS and elemental composition characterization of the boundary between smaller and spherical AuAg on g-C3N4:

[0061] like Figure 2 As shown in Figure 2, the g-C3N4 flakes are mainly composed of conjugated aromatic systems, and their planar structures can absorb visible light. The lattice fringes on the Au(111) and Ag(111) planes of the core-shell AuAg structure indicate the crystallization mode of the sample, further confirming the presence of AuAg and the favorable interactions on the interface of the g-C3N4 flakes ( Figure 2 b). The elemental map shows C (orange), N (green), Au (yellow), and Ag (purple), which strongly proves that AuAg is effectively attached to the sheet-like arrangement of g-C3N4.

[0062] (3) Zeta potential diagrams of AuNPs, AgNPs and AuAg compared with those of g-C3N4, Au@g-C3N4, Ag@g-C3N4 and

[0063] XRD characterization of AuAg@g-C3N4:

[0064] like Figure 3 As shown, since AuNPs, AgNPs and AuAg are all obtained by GEO reduction, their surface charges are shown to be stable negative charges by zeta potential test. In the XRD spectrum of g-C3N4, two broad peaks located at about 13.1° and 27.3°2θ are related to the (100) and (002) planes at d=0.676nm and 0.324nm, respectively, which proves that the synthesis of g-C3N4 is successful. In addition to the peak of g-C3N4, the XRD spectra of Au@g-C3N4, Ag@g-C3N4 and AuAg@g-C3N4 samples also show peaks at 38.2°, 44.1°, 64.7° and 76.8°2θ consistent with metal nanoparticles.

[0065] (4) In vitro antibacterial evaluation and characterization of the multimodal synergistic nanoplatform:

[0066] like Figure 4 As shown, through the production of intracellular ROS ( Figure 4 a) and Ag + The release concentration ( Figure 4 b) The antibacterial mechanism of AuNPs, AgNPs, AuAg, Au@g-C3N4, Ag@g-C3N4, and AuAg@g-C3N4 composites was studied. Starting from the addition of Au@g-C3N4, the ROS in the cells was induced to increase sharply until the production of ROS reached the highest level after the AuAg@g-C3N4 was cultured, which further proved that the AuAg@g-C3N4 composite killed bacteria by producing ROS under light. + The results showed that it had the strongest ability to produce ROS. Figure 4 b shows the Ag released from the AuAg@g-C3N4 composite. + The data showed that the AuAg@g-C3N4 composite material was cultured with bacteria for about 6 hours, and Ag + The release rates of Ag+ in the bacteria were almost the same. After that, the release of Ag+ inside the bacteria increased, while the release outside the bacteria decreased and stabilized at around 24h. During the culture process of about 6h, the AuAg@g-C3N4 composite material and bacteria released Ag+. + The absorption rate of AuAg@g-C3N4 composites by bacteria is almost the same as that of Ag + The release reaches its maximum value during this period.

[0067] Two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were selected as model bacteria, and their morphological changes were monitored using scanning electron microscopy (SEM). Figure 4 As shown in Figure c, after 5 minutes of illumination, the cell walls of the four untreated bacteria were intact and smooth, while the bacterial cell walls with the addition of AuAg@g-C3N4 composite materials lost their integrity and became collapsed, rough, wrinkled, and even broken, indicating that their photocatalytic bactericidal performance is superior.

[0068] (5) Photos of the colonies of Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa under light-triggered or non-triggered composite nanoplatforms:

[0069] like Figure 5As shown in the figure, under dark conditions, almost all bactericidal materials cannot completely kill bacteria. On the contrary, under light conditions, the first Au@g-C3N4 complex has the best therapeutic effect on Gram-positive bacteria, and when the AuAg@g-C3N4 complex exists, Gram-negative bacteria can also be killed 100%, which further confirms the significance of the synergistic effect of multiple bactericidal modes of photocatalysis.

[0070] (6) Characterization of the survival rates of Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa after using different concentrations of AuAg@g-C3N4 composite nanoplatforms:

[0071] like Figure 6 As shown in the figure, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AuAg@g-C3N4 at different concentrations against four bacteria were calculated by broth dilution method. Under light conditions, the calculated minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AuAg@g-C3N4 against Escherichia coli ( Figure 6 a), Staphylococcus aureus ( Figure 6 b) Bacillus subtilis ( Figure 6 c) and Pseudomonas aeruginosa ( Figure 6 d) had MIC values ​​of 50 mg L -1 , 25mg L -1 , 25mg L -1 and 25 mg L -1 , MBC values ​​were 100 mg L -1 , 50mg L -1 , 100mg L -1 and 50 mg L -1 The extremely low MBC and MIC values ​​highlight the outstanding synergistic bactericidal effect of the AuAg@g-C3N4 composite.

[0072] (7) Cytocompatibility test diagram of composite materials:

[0073] like Figure 7 As shown in Figure 2, L929 (mouse fibroblasts) were selected as model cells to verify the biocompatibility of the antibacterial material proposed in this study. The MTT test showed that at 20 mg mL -1 The survival rate of L929 cells was above 80% after co-culture with different materials for more than 24 hours, indicating that these materials have good biocompatibility ( Figure 7 a). AuAg@g-C3N4 composites and L929 in the range of 10 to 60 μg mL -1 Similar phenomenon also occurred in co-culture with different concentrations of , and the cell survival rate could still be maintained above 80% under light conditions ( Figure 7 b), indicating that the AuAg@g-C3N4 composite material has good biocompatibility.

[0074] The photoactivated AuAg@g-C3N4 composite material of the present invention is used to effectively kill a broad spectrum of bacteria such as Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa. The system combines GEO sterilization, ROS sterilization and toxic Ag + The release of the nanoparticles achieves a multifunctional synergistic antibacterial mode that integrates multiple bactericidal modes. Therefore, the nanoplatform can exert a broad-spectrum disinfection and anti-inflammatory function, making this new strategy promising in the future treatment of chronic wound bacterial infection-related diseases.

[0075] It should be noted that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Equivalent replacements or substitutions made on the basis of the above embodiments all fall within the protection scope of the present invention.

Claims

1. A method for constructing a light-triggered AuAg@g-C3N4 composite nanoplatform, characterized in that: The following steps are involved: The aqueous solution of AuAg core-shell metal nanomaterials was mixed with g-C3N4 to prepare the AuAg@g-C3N4 composite nanoplatform; The surface of the AuAg core-shell metal nanomaterial is loaded with ginger essential oil.

2. The construction method according to claim 1, characterized in that: The aqueous solution of the AuAg core-shell metal nanomaterial is heated to 80-100° C., mixed with g-C 3 N 4 , and the reaction is continued for 1-3 hours.

3. The construction method according to claim 1, characterized in that: The concentration of the aqueous solution of the AuAg core-shell metal nanomaterial is 37.5×10 -3 mM, the molar ratio of the AuAg core-shell metal nanomaterial to g-C3N4 is 1.5×10 -6 .

4. The construction method according to claim 1, characterized in that: The preparation method of the AuAg core-shell metal nanomaterial comprises the following steps: using chloroauric acid aqueous solution and silver nitrate aqueous solution as raw materials and ginger essential oil as a reducing agent to prepare the AuAg core-shell metal nanomaterial.

5. The construction method according to claim 4, characterized in that: In the reaction system, the concentration of the chloroauric acid aqueous solution is 10-30 mM; the concentration of the silver nitrate aqueous solution is 10-30 mM; the mass fraction of the ginger essential oil is 0.05-0.15 g / mL, the reaction temperature is 60-80° C., and the reaction time is 1-5 min.

6. The construction method according to claim 1, characterized in that: The preparation method of g-C3N4 is as follows: urea is used as a raw material and is calcined at a constant temperature in an air atmosphere; the constant temperature calcination temperature can be selected from 200 to 600° C., and the reaction time is 1 to 4 hours.

7. The AuAg@g-C3N4 composite nanoplatform prepared by the construction method according to any one of claims 1 to 6.

8. Application of the AuAg@g-C3N4 composite nano-platform as claimed in claim 7 in multi-mode broad-spectrum sterilization.

9. Use of the AuAg@g-C3N4 composite nano-platform as claimed in claim 7 in the preparation of bactericidal materials, bactericidal pharmaceutical preparations, and bactericidal medical devices.

10. Use of the AuAg@g-C3N4 composite nanoplatform as claimed in claim 7 in synergistically killing Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa under light conditions.

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