A Zn-DPA complex and a preparation method and application thereof

Abstract

This invention belongs to the field of fluorescent materials and biomedical engineering technology, and relates to a Zn-DPA complex, its preparation method, and its applications. The Zn-DPA complex is a zinc-dipyridine methylamine (Zn-DPA) complex with different alkyl chain lengths. This invention discloses that fluorescent dyes combined with zinc-dipyridine methylamine (Zn-DPA) complexes of different alkyl chain lengths can regulate the targeting of Gram bacteria. The preparations made in this way exhibit near-infrared II (NIR-II) Gram bacteria selectivity, and possess high fluorescence signal-to-noise ratio, good photothermal conversion efficiency, and biocompatibility. It can be used for selective imaging and photothermal therapy of Gram bacterial infections, and has potential application value in the prevention and treatment of drug-resistant bacterial infections and related biomedical research.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of fluorescent materials and biomedical engineering, specifically relating to Gram-selective targeted Zn-DPA complexes, their preparation methods, and applications. Background Technology

[0002] Near-infrared II (NIR-II, 1000-1700 nm) fluorescence imaging has advantages such as low tissue scattering, large penetration depth, and weak background autofluorescence, and has become an important tool for the diagnosis of bacterial infections. At the same time, NIR-II photothermal therapy (PTT) can use laser-induced photothermal effects to destroy bacterial membranes, making it less likely to induce drug resistance and suitable for the treatment of drug-resistant bacterial infections.

[0003] However, existing NIR-II photosensitizers lack Gram selectivity, easily disrupt normal flora, and are difficult to achieve precise treatment.

[0004] Therefore, there is an urgent need to develop complexes with Gram-selectivity. Summary of the Invention

[0005] The purpose of this invention is to provide the design, synthesis, and construction of Gram-targeting nanoparticles of Gram-selective complexes and near-infrared II (NIR-II) selective antibacterial photosensitizers or fluorescent probes, as well as their application in selective fluorescence imaging and photothermal therapy for bacterial infections. This aims to address the shortcomings and lack of selectivity in existing fluorescent probes or photosensitizers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A Zn-DPA complex has the following structural formula: .

[0007] A method for preparing a Zn-DPA complex includes the following steps: (1) Reaction of di-(2-pyridinemethyl)amine with alkyl bromide yields a product with C 11 C 14 Or C 18 Di-(2-pyridinemethyl)amine derivatives with alkyl chains; (2) The derivative was reacted with ZnCl2 in a solvent at a molar ratio of 1:1 to obtain the Zn-DPA complex.

[0008] Preferably, di-(2-pyridinemethyl)amine and its alkyl bromide, NaI and K2CO3 are dissolved in acetonitrile in a molar ratio of 1:1:1:3, refluxed overnight, and purified by column chromatography; the C 11 C 14 Or C 18 The alkyl chain is a straight chain; The alkyl bromide is 1-bromoundecane, 1-bromotetradecane, or 1-bromooctadecane.

[0009] This invention also discloses the application of the Zn-DPA complex described above in the preparation of antibacterial agents and / or fluorescent probes.

[0010] A Gram-selective nanoparticle, wherein the nanoparticle is self-assembled from the Zn-DPA complex and a fluorescent material, the fluorescent material having the following structural formula:

[0011] Formula 1 Formula 2 In Equation 1 or Equation 2: n=0,1; Y=0,1; X is selected from S or O; R stands for F5-TPB.

[0012] The preparation method of the fluorescent material includes the following steps: (1) Using chalcone of Formula 1 as the starting material, intermediate 2 of Formula 2 is obtained by Michael addition reaction with cyclopentanone or cyclohexanone; (2) Intermediate 2 is catalyzed by the oxidant perchloric acid or the sulfurizing agent thioacetic acid to generate intermediate 3 of formula 3; (3) Intermediate 3 reacts with Wilsmayer reagents of formula 4 / 5 / 6 via the Wilsmayer-Hacker reaction to obtain PCs; (4) Finally, PCs were dissolved in acetonitrile and then quickly added to the acetonitrile solution of sodium tetra(4-fluorophenyl)borate dihydrate. The solvent was evaporated and purified by rapid column chromatography to obtain the fluorescent material CPCs.

[0013] The synthetic route for the PCs is as follows:

[0014] The PCs have any of the following structural formulas:

[0015]

[0016] A method for preparing Gram-selective nanoparticles includes the following steps: The fluorescent material and Zn-DPA complex were dissolved in tetrahydrofuran, rapidly injected into PBS buffer under sonication in an ice bath, and concentrated after sonication to obtain nanoparticles.

[0017] Preferably, the molar ratio of fluorescent material to Zn-DPA complex is 1:8; the pH of PBS buffer is 7.4; and the rejection rate of ultrafiltration tube is 30 kDa.

[0018] The aforementioned nanoparticles can be used in Gram-selective photothermal antibacterial agents or Gram-selective fluorescent reagents.

[0019] Furthermore, the nanoparticles exhibit differentiated recognition of Gram-positive and Gram-negative bacteria, with an excitation wavelength of 1064 nm, specifically: The alkyl group in the Zn-DPA complex is a short-chain C. 11 Targets Gram-positive bacteria; alkyl group is a long chain C 18 Targets Gram-negative bacteria; alkyl group is a medium-chain C 14 It can simultaneously target both Gram-positive and Gram-negative bacteria; The Gram-positive bacteria were MRSA (methicillin-resistant Staphylococcus aureus). Staphylococcus aureus Bacillus subtilis Bacillus subtilis The Gram-negative bacteria are E. coli (E. coli) Escherichia coli Pseudomonas aeruginosa Pseudomonas aeruginosa .

[0020] The present invention also provides a Gram-selective antibacterial composition comprising the aforementioned nanoparticles as the active ingredient, and further comprising a pharmaceutically acceptable carrier, such as mannitol or physiological saline.

[0021] The beneficial effects of this invention are: This invention achieves differentiated recognition of Gram-positive and Gram-negative bacteria through structural regulation, namely, an alkyl chain regulation strategy: the alkyl chain length (C) of the Zn-DPA complex... 11 C 14 C 18 The size and hydrophobicity of nanoparticles are determined by: Short chains (C 11 ): The small size of the nanoparticles (69.2 nm) allows them to easily penetrate the thick peptidoglycan layer of Gram-positive bacteria and bind to the inner membrane; Long chain (C) 18 Nanoparticles are highly hydrophobic and readily bind to and accumulate in the hydrophobic regions of the outer membrane of Gram-negative bacteria. Mid-chain (C) 14 ): With a moderate size and hydrophobicity, it can simultaneously penetrate the peptidoglycan layer of Gram-positive bacteria and bind to the outer membrane of Gram-negative bacteria.

[0022] CPC1050 / Zn-DPA 18The high hydrophobicity of nanomaterials enables them to strongly bind to and locally accumulate in the hydrophobic regions of the outer membrane of Gram-negative bacteria, thereby disrupting the outer membrane and achieving highly efficient sterilization. CPC1050 / Zn-DPA, with its medium size and hydrophobicity, is an example. 14 Nanomaterials can not only penetrate the peptidoglycan layer of Gram-positive bacteria, but also bind to the outer membrane of Gram-negative bacteria, thereby achieving simultaneous killing of both Gram-positive and Gram-negative bacteria.

[0023] The fluorescent material in the nanoparticles of this invention achieves a counterion pairing strategy by adding sodium tetra(4-fluorophenyl)borate. The large-volume hydrophobic counterion can act as a steric barrier to inhibit dye aggregation, and at the same time, as a soft anion, it weakens the polarity-induced symmetry destruction, significantly improving absorption, fluorescence and photothermal properties.

[0024] This invention provides a high-performance photosensitizer that emits in the near-infrared II region, exhibiting excellent tissue penetration and a high signal-to-noise ratio; optical performance: maximum absorption wavelength in aqueous solution ≈1050nm, matching a 1064nm laser; imaging depth up to 5mm (twice that of IR26 and ICG). Photothermal performance: 1064nm laser (0.2-0.8W / cm²) 2 After irradiation for 10 minutes, the temperature of the nanoparticles rises to 52-60℃, with a photothermal conversion efficiency of 43%-46%, and the performance does not degrade after 5 heating-cooling cycles. Attached Figure Description

[0025] Figure 1 The nuclear magnetic resonance spectrum of CPC1050 prepared in Example 3; Figure 2 CPC1050 / Zn-DPA 11 , 14 , 18 Absorption spectrum (A) and normalized emission (B) of nanoparticles in PBS; Figure 3 CPC1050 / Zn-DPA 11 , 14 , 18 Comparison of particle size distribution (A) and photostability (B) of nanoparticles in PBS; Figure 4 Example 8: In vitro selective antibacterial validation (A: via CPC1050 / Zn-DPA) 11 , 14 , 18 Post-treatment MRSA, E. coli B: Colony count results using CPC1050 / Zn-DPA; 11 , 14 , 18Post-treatment MRSA, E. coli SEM images of bacteria; C: via CPC1050 / Zn-DPA 11 , 14 , 18 Post-treatment MRSA, E. coli Nucleic acid / protein leakage detection; D: DiO-labeled CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticles with MRSA and E. coli Combined confocal microscopy images; E: via CPC1050 / Zn-DPA 11 , 14 , 18 After processing Bacillus subtilis , Pseudomonas aeruginosa (survival rate) Figure 5 This is an NIR-II fluorescence imaging image of the double-infected mouse model in Example 9; Figure 6 This is a NIR-II fluorescence imaging image of the major organs in the double-infected mouse model of Example 9; Figure 7 For Example 9 MRSA, E. coli Graphs showing changes in the infection site of mice after treatment from 0 to 8 days; Figure 8 Example 10 MRSA, E. coli H&E staining and Masson staining images of mouse models after 8 days of in vivo treatment; Figure 9 Example 10 MRSA, E. coli Serum inflammatory factor levels in each group after 8 days of in vivo treatment in mouse models; Figure 10 Example 10 MRSA, E. coli Tissue sections of major organs after 8 days of in vivo treatment in mouse models; Figure 11 Example 11 CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticles in (50 μg·mL) -1 1064 nm laser irradiation (0.8 W·cm) -2 Photothermal conversion efficiency (PCE) at ) Figure 12 CPC1050 / Zn-DPA 11 , 14 , 18 Image showing the contact angle measurement of nanoparticles. Detailed Implementation

[0026] Example 1 Synthesis of compound PC939

[0027] Synthetic steps of compound 1: A mixture of cyclohexanone (40 mmol, 4.1 mL) and pyrrolidine (40 mmol, 3.3 mL) was dissolved in toluene (40 mL) and refluxed in a round-bottom flask for 4 hours. After removing the solvent, the remaining mixture was dissolved in 1,4-dioxane. Chalcone (20 mmol) was added and refluxed for 2 hours. After cooling to room temperature, the reaction was quenched with water (120 mL), followed by extraction with ethyl acetate (3 times, 40 mL each). The organic layers were combined, dried over anhydrous sodium sulfate, and concentrated to give the crude product, which was purified by rapid column chromatography (silica gel, eluent: n-hexane / ethyl acetate) (yield 67%).

[0028] Synthesis of Compound 2: Boron trifluoride ether salt (2 mmol, 0.25 mL) was added to a solution of Compound 1 (2 mmol, 0.36 g) in acetic anhydride (4 mL), and the mixture was refluxed for 4 hours. After cooling the mixture to room temperature, diethyl ether (50 mL) was added. The resulting precipitate was filtered off, washed with diethyl ether, and dried to give yellow powder 3 (185 mg). Yield: 41%.

[0029] Synthetic steps of compound PC939: Compound 2 (0.02 mmol, 7.8 mg), compound 3 (0.01 mmol, 2.9 mg), and anhydrous sodium acetate (0.02 mmol, 1.6 mg) were dissolved in acetic anhydride (1 mL) and stirred at 70 °C for 2 hours. The reaction mixture was poured into diethyl ether (20 mL). The precipitate was filtered, washed with diethyl ether, and dried under reduced pressure to give the crude product, which was purified to the dark green solid fluorophore PC939 by rapid column chromatography (silica gel, DCM / MeOH, 50:1, v / v). Yield: 41%. 1 H NMR (600 MHz, Chloroform- d ) δ 8.18 – 8.04 (m, 7H), 7.52 – 7.29 (m,14H), 6.96 (s, 3H), 2.39 – 2.23 (m, 8H), 1.89 (s, 4H). Example 2 Synthesis of compound PC945

[0030] Synthetic steps of compound 4: Chalcone (5 g, 24 mmol) was dissolved in diethyl ether (20 mL) in a well-stirred, cooled solution (ice-salt bath), followed by dropwise addition of a cooled mixture of perchloric acid (70%, 1.72 mL) and ethyl acetate (5 mL). Cyclopentanone (2.12 mL) was then added dropwise, followed by another portion of the cooled mixture of perchloric acid (70%, 1.72 mL) and ethyl acetate (5 mL). The reaction mixture was stirred at 0 °C for 5 hours. The separated crystals were filtered and washed with diethyl ether to give compound 4, which crystallized from glacial acetic acid as deep purple prismatic crystals (30% yield).

[0031] Synthetic steps of compound PC945: Compound 4 (0.02 mmol, 7.4 mg), compound 3 (0.01 mmol, 2.9 mg), and anhydrous sodium acetate (0.02 mmol, 1.6 mg) were dissolved in acetic anhydride (1 mL) and stirred at 70 °C for 2 hours. The reaction mixture was poured into diethyl ether (20 mL). The precipitate was filtered, washed with diethyl ether, and dried under reduced pressure to give the crude product. Purification was performed by rapid column chromatography (silica gel, DCM / MeOH, 50:1, v / v) to give the deep purple solid fluorophore PC945. Yield: 44%. 1 H NMR (600 MHz, Chloroform- d ) δ 7.65 – 7.58 (m, 20H), 5.33 (s, 1H),5.31 (d, J = 1.5 Hz, 2H), 5.29 (s, 1H), 3.37 – 3.30 (m, 8H). Example 3 Synthesis of compound PC1050

[0032] Synthetic steps of compound 5: A mixture of cyclopentanone (40 mmol, 3.4 mL) and pyrrolidine (40 mmol, 3.3 mL) was dissolved in toluene (40 mL) and refluxed in a round-bottom flask for 4 hours. After removing the solvent, the remaining mixture was dissolved in 1,4-dioxane. Chalcone (20 mmol) was added and refluxed for 2 hours. After cooling to room temperature, the reaction was quenched with water (120 mL), followed by extraction with ethyl acetate (3 times, 40 mL each). The organic layers were combined, dried over anhydrous sodium sulfate, and concentrated to give the crude product, which was purified by rapid column chromatography (silica gel, eluent: n-hexane / ethyl acetate) (yield 65%). Synthetic steps of compound 6: Thioacetic acid (12.7 mmol, 0.9 mL) was added to a solution of compound 5 (5.8 mmol) in diethyl ether (10 mL). After all reagents were completely dissolved, boron trifluoride diethyl ether (34.7 mmol, 4.4 mL) was added dropwise to the mixture, followed by reflux for 6 hours. The reaction mixture was then cooled to room temperature and quenched with 1 mL of water. It was then poured into diethyl ether (100 mL), resulting in a large amount of yellow solid. After filtration to remove the solid, the mixture was washed with diethyl ether and dried to give compound 6 (yield 49%).

[0033] Synthetic steps of compound PC1050: Compound 5 (0.02 mmol, 7.5 mg), compound 3 (0.01 mmol, 2.9 mg), and anhydrous sodium acetate (0.02 mmol, 1.6 mg) were dissolved in acetic anhydride (1 mL) and stirred at 70 °C for 2 hours. The reaction mixture was poured into diethyl ether (20 mL). The precipitate was filtered, washed with diethyl ether, and dried under reduced pressure to give the crude product. Purification was performed by rapid column chromatography (silica gel, DCM / MeOH, 50:1, v / v) to give the deep purple solid fluorophore PC1050. Yield: 46%. 1 H NMR (600 MHz, Chloroform-d) δ 7.81 (d, J = 7.4 Hz, 1H), 7.74 – 7.61(m, 4H), 7.59 – 7.41 (m, 11H), 7.40 – 7.31 (m, 4H), 5.30 (s, 3H), 3.52 – 2.80(m, 9H). Example 4 Synthesis of compound PC1120

[0034] Synthetic steps of compound PC1120: Compound 2 (0.02 mmol, 7.8 mg), compound 7 (0.01 mmol, 3.6 mg), and anhydrous sodium acetate (0.02 mmol, 1.6 mg) were dissolved in acetic anhydride (1 mL) and stirred at 70 °C for 2 hours. The reaction mixture was poured into diethyl ether (20 mL). The precipitate was filtered off, washed with diethyl ether, and dried under reduced pressure to give the crude product. The crude product was purified by rapid column chromatography (silica gel, DCM / MeOH, 50:1, v / v) to give the deep purple solid fluorophore PC1120. Yield: 50%. 1 H NMR (600 MHz, Chloroform- d) δ 8.95 – 7.28 (m, 21H), 5.30 (s, 3H), 1.56 (s, 8H), 1.26 (s, 4H). Example 5 Synthesis of compound PC1145

[0035] Synthesis of compound PC1145: Compound 2 (0.02 mmol, 7.8 mg), compound 8 (0.01 mmol, 1.9 mg), and anhydrous sodium acetate (0.02 mmol, 1.6 mg) were dissolved in acetic anhydride (1 mL) and stirred at 70 °C for 2 hours. The reaction mixture was poured into diethyl ether (20 mL). The precipitate was filtered, washed with diethyl ether, and dried under reduced pressure to give the crude product. Purification by rapid column chromatography (silica gel, DCM / MeOH, 50:1, v / v) yielded the deep purple solid fluorophore PC1145. Yield: 50%. 1 H NMR (600 MHz, Chloroform- d ) δ 8.17 (s, 3H), 7.93 – 7.90 (m, 3H), 7.56(dd, J = 5.2, 2.0 Hz, 5H), 7.54 – 7.48 (m, 6H), 7.41 – 7.36 (m, 4H), 6.96 (s, 2H), 5.29 (s, 1H), 3.17 (s, 4H), 1.25 (s, 8H), 1.19 (s, 4H). Example 6 Zn-DPA 11 Synthesis of coordination compounds

[0036] 1. Synthesis of DPA-11: Di-(2-pyridinemethyl)amine (2.00 g, 10.04 mmol), 1-bromoundecane (2.35 g, 10.04 mmol), NaI (1.50 g, 10.04 mmol), and K₂CO₃ (4.16 g, 30.12 mmol) were dissolved in acetonitrile and refluxed overnight. The reaction mixture was evaporated to dryness under reduced pressure, and then subjected to silica gel column chromatography (eluting with dichloromethane) to give a brown oily liquid, DPA-11 (2.23 g, 64%). The ¹H NMR characterization results were consistent with the structural formula.

[0037] Zn-DPA 11Synthesis: DPA-11 (0.353 g, 0.998 mmol) and ZnCl2 (0.136 g, 0.998 mmol) were dissolved in methanol, refluxed for 3 hours, and evaporated to dryness to obtain a brown solid.

[0038] Zn-DPA 14 Zn-DPA 18 Synthesis of coordination compounds and Zn-DPA 11 The synthesis steps are the same, except that 1-bromoundecane is replaced with 1-bromotetradecane and 1-bromooctadecane.

[0039] Example 7 CPC1050 / Zn-DPA 11 , 14 , 18 Preparation of nanoparticles Preparation of CPC1050: PC1050 was reacted with sodium tetra(4-fluorophenyl)borate in dichloromethane at room temperature for 4 hours, precipitated with diethyl ether, and purified by column chromatography with a yield of 48%. Nanoparticle preparation: CPC1050 (0.1 mmol) was reacted with Zn-DPA separately. 11 Zn-DPA 14 Zn-DPA 18 (0.8 mmol) was dissolved in tetrahydrofuran (5 mL), and rapidly injected into PBS (pH=7.4, 45 mL) under sonication in an ice bath. After sonication for 10 minutes, the solution was concentrated to 5 mL using a 30 kDa ultrafiltration tube to obtain nanoparticles, which were then stored at 4 °C.

[0040]

[0041] Figure 2 A is CPC1050 / Zn-DPA 11 , 14 , 18 Normalized absorption; Figure 2 B is CPC1050 / Zn-DPA 11 , 14 , 18 Normalized launch.

[0042] CPC1050 / Zn-DPA was determined by DLS. 11 , 14 , 18 The particle size distribution of nanoparticles, the results are as follows: Figure 3 As shown in Figure A, CPC1050 / Zn-DPA 11 , 14 , 18The average particle sizes were 69.2 nm, 98.5 nm, and 187.9 nm, respectively. The alkyl chain lengths (C1, C2, and C3) of the Zn-DPA complexes were... 11 C 14 C 18 It can control the size of nanoparticles.

[0043] Figure 3 B is CPC1050 / Zn-DPA (C 11 , 14 , 18 The photostability of the light under 1064 nm laser irradiation.

[0044] Example 8 CPC1050 / Zn-DPA 11 , 14 , 18 In vitro selective antibacterial experiment of nanoparticles In vitro antibacterial experiment: The nanoparticles prepared in Example 7 were diluted to 50 μM and reacted with MRSA (methicillin-resistant Staphylococcus aureus). Staphylococcus aureus ), E. coli (Escherichia coli) Escherichia coli E. coli B. subtilis Bacillus subtilis P. aeruginosa (Pseudomonas aeruginosa) Pseudomonas aeruginosa ) bacterial solution (1×10 6 CFU / mL) mixed, 1064 nm laser (0.8 W / cm) 2 Irradiate for 10 minutes.

[0045] like Figure 4 As shown in Figure A, the colony count after plate culture indicates: CPC1050 / Zn-DPA 11 The survival rate of MRSA is 3.5%. E. coli Survival rate 93.9%; CPC1050 / Zn-DPA 14 The survival rate of MRSA was 4.1%. E. coli Survival rate 6.8%; CPC1050 / Zn-DPA 18 The survival rate of MRSA was 94.5%. E. coli Survival rate 5.9%; control group PC1050 / Zn-DPA 14 MRSA, E. coliThe survival rates were 45% and 52%, respectively; MRSA, ATCC 43300, B. subtilis, CICC 10002 and P. aeruginosa, CICC21626 were purchased from the China Industrial Microbial Culture Collection Center. E. coli BNCC185254 was purchased from BeiNa Biotechnology.

[0046] Membrane damage verification: From Figure 4 SEM observations in B revealed CPC1050 / Zn-DPA 11 and CPC1050 / Zn-DPA 14 The treated MRSA group and CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 Processing E. coli The group showed signs of damage such as cell membrane rupture and cytoplasmic extravasation under scanning electron microscopy (SEM). Normal cells in other treatment groups and the control group showed no obvious damage.

[0047] OD260 nm detection, such as Figure 4 As shown in C. CPC1050 / Zn-DPA 11 and CPC1050 / Zn-DPA 14 The treated MRSA group and CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 Processing E. coli All groups showed significant protein and nucleic acid leakage, indicating cell damage.

[0048] like Figure 4 As shown in D: CPC1050 / Zn-DPA 11 and CPC1050 / Zn-DPA 14 It can be combined with MRSA, CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 with Escherichia coli E. coli They can be combined.

[0049] like Figure 4 E shows: CPC1050 / Zn-DPA 11 and CPC1050 / Zn-DPA 14 The treatment of B. subtilis group and CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 The survival rate of bacteria in the treated P. aeruginosa group was very low.

[0050] Example 9 CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticle in vivo Gram-selective imaging and therapy experiment 1. Establishment of a double-infection mouse model: Balb / c mice were subcutaneously injected with MRSA (10) on the left side of their backs. 7 CFU / mL, 100μL), injected on the right side E. coli (10) 7 A dual infection model was constructed using CFU / mL (100 μL); 1) PBS + laser, 2) CPC1050 / Zn-DPA. 11 + laser, 3) CPC1050 / Zn-DPA 14 + laser, and 4) CPC1050 / Zn-DPA 18 + laser (laser power: 0.8 W cm) -2 ).

[0051] 2. Selective imaging: Caudal vein injection of CPC1050 / Zn-DPA 11 (2 mg / mL, 150 μL), 1064 nm laser excitation, 1150 nm filter signal collection; 6 hours after injection, the signal-to-background ratio at the left MRSA site was 28.5, and at the right... E. coli The site-specific confidence ratio is 4.7; if C is injected... 18 Type, right-side signal-to-background ratio 25.3, left-side signal-to-background ratio 3.4; if C is injected 14 The two sides have a back-to-back ratio of 11.2 and 10.6, respectively.

[0052] Example 10 CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticle in vivo Gram-selective therapy experiment 1. Model construction: Balb / c mice were subcutaneously injected with MRSA (10 mg / L) on the left side of their backs. 7 CFU / mL, 100μL) and E. coli (10) 7 (CFU / mL, 100μL), to construct an infection model; 1) PBS + laser, 2) CPC1050 / Zn-DPA 11 +laser, 3) CPC1050 / Zn-DPA 14 + laser, and 4) CPC1050 / Zn-DPA 18 + laser (laser power: 0.8 W cm)-2 ).

[0053] 2. Selective treatment: After injecting nanoparticles, the infected sites on both sides are irradiated with a 1064nm laser (0.5W / cm²) for 10 minutes; the results are observed on the 8th day. Figure 7 As shown: the abscess necrosis cavity area in the PBS-treated group was as high as 95.6%, while that in the CPC1050 / Zn-DPA group was much smaller. 11 and CPC1050 / Zn-DPA 14 The treated MRSA infection groups (3.1% and 4.6%), CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 Processing E. coli The infection groups (6.9% and 7.2%) showed significant healing effects, with the abscess necrosis cavity area shrinking to 3.1-7.2%.

[0054] like Figure 8 As shown, H&E staining results indicate that CPC1050 / Zn-DPA 11 MRSA-infected mice treated with CPC1050 / Zn-DPA 18 Treatment E. coli Infected mice, and CPC1050 / Zn-DPA 14 The skin tissue of the treated double-infected mice healed completely, with intact structure. Masson staining further revealed a significant increase in collagen deposition in the regenerated tissue of the treated mice, indicating good wound regeneration. The control group, however, exhibited numerous intercellular gaps and structural incompleteness, with no significant wound regeneration.

[0055] like Figure 9 As shown, after day 8 of treatment, CPC1050 / Zn-DPA 14 In treated double-infected mice, serum inflammatory factors (TNF-α, IL-1β) returned to normal levels, and CPC1050 / Zn-DPA 11 In treated MRSA-infected mice, serum inflammatory factors (TNF-α, IL-1β) returned to normal levels; CPC1050 / Zn-DPA 18 Treatment E. coli The serum inflammatory factors (TNF-α, IL-1β) of the infected mice returned to normal levels.

[0056] like Figure 10 As shown, CPC1050 / Zn-DPA 11 , 14 , 18 Histological analysis of the major organs also revealed no signs of toxicity.

[0057] Example 11 Measurement of photothermal therapy (PTT) efficacy and photothermal conversion efficiency (PCE): PC1050 / Zn-DPA 11 , 14 , 18 and CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticles were diluted to different concentrations (10, 20, 30, 40, and 50 μg·mL). -1 The total volume was 2 mL. Then, over 10 minutes, a 1064 nm laser was used at different laser power densities (0.2, 0.5, and 0.8 W·cm⁻¹). -2 Temperature was recorded when each sample was excited. Temperature changes were monitored using a digital thermometer (TES-1310). PCE was calculated using the following formula: η =

[0058] Where h represents the heat transfer coefficient, A represents the surface area of ​​the container, and T Max and T Surr Q represents the maximum stable temperature and the ambient temperature, respectively. Dis I represents the heat dissipation of the dissolved substance and container, I represents the laser power used, and A represents the absorbance of the compound at the excitation wavelength.

[0059] The hA product can be calculated using the following formula: τ s =

[0060] Where m D Represents water, c D This represents the heat capacity of water.

[0061] τs can be calculated using the following formula: t = -τ s ln(

[0062] Where T RT t represents the real-time temperature during the cooling period, and t represents the real-time time during the cooling period.

[0063] CPC1050 / Zn-DPA 11 , 14 , 18 Nanoparticles in (50 μg·mL) -1 1064 nm laser irradiation (0.8 W·cm) -2 Photothermal conversion efficiency (PCE) under the following conditions: Figure 11As shown, the temperature of CPC1050 / Zn-DPA NPs rapidly rises to 60℃ within 10 minutes, sufficient for photothermal sterilization of pathogenic microorganisms. CPC1050 / Zn-DPA 11 CPC1050 / Zn-DPA 14 and CPC1050 / Zn-DPA 18 The photothermal conversion efficiency is as high as 46.6%, 45.2% and 43.8%, which is significantly better than most commercial photothermal agents.

Claims

1. A nanoparticle with Gram selectivity, characterized in that, The nanoparticles are self-assembled from a Zn-DPA complex and a fluorescent material, wherein the Zn-DPA complex is selected from one of the following structural formulas: ； Zn-DPA 11 Zn-DPA 14 Zn-DPA 18 ; The fluorescent material has the following structural formula: ； Formula 1 Formula 2 In Equation 1 or Equation 2: n=0,1； Y=0,1； X is selected from S or O; R stands for F5-TPB.

2. The method for preparing Gram-selective nanoparticles according to claim 1, characterized in that, Includes the following steps: The fluorescent material and Zn-DPA complex were dissolved in tetrahydrofuran, rapidly injected into PBS buffer under sonication in an ice bath, and concentrated after sonication to obtain nanoparticles.

3. The method for preparing Gram-selective nanoparticles according to claim 2, characterized in that, The molar ratio of fluorescent material to Zn-DPA complex was 1:8; the pH of PBS buffer was 7.4; and the rejection rate of the ultrafiltration tube was 30 kDa.

4. The application of the nanoparticles as described in claim 1 in Gram-selective photothermal antibacterial agents or Gram-selective fluorescent reagents.

5. The application as described in claim 4, characterized in that, The nanoparticles exhibit differential recognition of Gram-positive and Gram-negative bacteria, with an excitation wavelength of 1064 nm, specifically: The alkyl group in the Zn-DPA complex is a short-chain C. 11 Targets Gram-positive bacteria; alkyl group is a long chain C 18 Targets Gram-negative bacteria; alkyl group is a medium-chain C 14 It can simultaneously target both Gram-positive and Gram-negative bacteria; The Gram-positive bacteria are MRSA and Bacillus subtilis. Bacillus subtilis The Gram-negative bacteria are E. coli Pseudomonas aeruginosa Pseudomonas aeruginosa .

6. A Gram-selective antibacterial composition, characterized in that, The active ingredient comprises the nanoparticles as described in claim 1, and also comprises a pharmaceutically acceptable carrier.

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