Copper-iron nanocrystalline material, preparation method thereof and application of copper-iron nanocrystalline material in treatment of bacteremia
By synthesizing copper-iron nanocrystals in a one-pot process and utilizing electrostatic adsorption and Fenton reaction to synergistically disrupt bacterial cell membranes, the problem of balancing biocompatibility and antibacterial efficacy of nanomaterials in the treatment of bacteremia has been solved, achieving highly efficient and safe antibacterial effects and reducing the risk of drug resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-19
AI Technical Summary
Existing nanomaterials have issues with biocompatibility and long-term toxicity in the treatment of bacteremia, and it is difficult to balance antibacterial efficacy and specificity, resulting in a high risk of drug resistance and making them difficult to apply clinically.
Copper-iron nanocrystals were synthesized in a one-pot method with a copper-iron molar ratio of 8:2. Polyvinylpyrrolidone (PVP) with peroxy groups was modified on the surface. Through electrostatic adsorption and Fenton reaction, PVP synergistically destroyed bacterial cell membranes, generating a large number of active oxidants and achieving multi-target attack.
It significantly improved the inhibition rate against drug-resistant strains to 98.1%, and at effective concentrations, it was non-toxic to mammalian cells and erythrocytes, with no obvious organ pathological damage in vivo. It has excellent biocompatibility and reduces the risk of drug resistance.
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Figure CN122056918A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of biomedical nanomaterials technology, specifically relating to a copper-iron nanocrystalline material with a specific copper-iron molar ratio, its preparation method, antibacterial mechanism, and its application in the preparation of antibacterial drugs. Background Technology
[0002] Bacteremia is a systemic infectious disease caused by pathogens invading the bloodstream. It has a high morbidity and mortality rate, especially in immunocompromised patients. Current clinical treatment mainly relies on antibiotics, but with the widespread emergence of drug-resistant strains, the effectiveness of traditional therapies is increasingly limited. Copper-iron nanocrystals, as a novel nanomaterial, exhibit multiple advantages through their unique physicochemical properties, including highly efficient bactericidal activity, synergistic therapy, and anti-biofilm activity. They can not only effectively overcome drug resistance problems but also enhance the body's ability to clear pathogens by regulating the immune microenvironment, providing a new breakthrough in the treatment of bacteremia.
[0003] Nanomaterials exhibit significant advantages in antibacterial therapy due to their size effect, high specific surface area, and tunable physicochemical properties. First, nanomaterials can achieve targeted delivery through surface functionalization, precisely delivering antibacterial components to the site of infection, thereby increasing local drug concentration and reducing systemic toxicity. For example, metal nanoparticles (such as silver and zinc oxides) can disrupt bacterial membrane structures by releasing metal ions, leading to leakage of intracellular contents and bacterial death. Second, nanomaterials can penetrate biofilm barriers, effectively combating bacterial biofilm-associated infections, a common cause of bacteremia. Biofilms are structural communities formed by bacteria on their surfaces, significantly enhancing bacterial resistance to antibiotics. The small size of nanoparticles allows them to easily penetrate the biofilm matrix and directly act on the internal bacterial community.
[0004] Despite their promising prospects, nanomaterials still face several unresolved shortcomings in their clinical application for bacteremia treatment. The primary issues lie in biocompatibility and long-term toxicity. Some nanomaterials degrade slowly in vivo, potentially leading to the long-term accumulation of metal ions in organs such as the liver and spleen, causing oxidative stress damage or organ fibrosis. Furthermore, striking a balance between the antibacterial efficacy and specificity of nanomaterials is challenging. Minimizing damage to normal tissues such as erythrocytes and endothelial cells while effectively killing bacteria is a crucial consideration in the design of nanoparticle formulations. These factors collectively constitute the main obstacles to the clinical translation of antibacterial nanomaterials. Summary of the Invention
[0005] Objective: The purpose of this invention is to overcome the shortcomings of existing single nanomaterials, such as limited antibacterial activity, easy induction of drug resistance, and poor biocompatibility, by providing a copper-iron nanocrystalline material with synergistic antibacterial effects and high biocompatibility. This nanomaterial exhibits multiple synergistic mechanisms, capable of disrupting bacterial cell membranes and inducing the accumulation of large amounts of ROS within bacteria, thereby achieving bactericidal effects and effectively reducing the risk of drug resistance. Furthermore, the copper-iron nanocrystalline material possesses excellent biocompatibility and high safety, effectively overcoming the deficiencies and defects mentioned in the prior art.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] The inventive point of this application is to provide copper-iron nanocrystals for treating bacteremia.
[0008] This application describes a one-pot synthesis of copper-iron nanocrystals. Polyvinylpyrrolidone (PVP) is dissolved in distilled water. Then, aqueous solutions of CuCl₂·2H₂O and FeCl₂·4H₂O are added to the PVP solution and stirred until completely dissolved. NaOH and H₂O₂ aqueous solutions are added to the mixture, and after rapid stirring, the product is collected by centrifugation and washing. Finally, the final copper-iron nanocrystal material is obtained by freeze-drying.
[0009] Preferably, the copper-iron nanocrystalline material is a copper-iron composite oxide nanocrystalline material, wherein the molar ratio of copper to iron is 8:2, and the copper-iron nanocrystalline material contains two crystal phases: CuO and Fe3O4.
[0010] Preferably, the surface of the copper-iron nanocrystalline material is modified with a stabilizer containing peroxy groups, such as polyvinylpyrrolidone (PVP), wherein the peroxy groups are derived from the oxidant H2O2 used in the preparation process.
[0011] Preferably, the copper-iron nanocrystals used to treat bacteremia have excellent therapeutic effects on bacteremia and can effectively eliminate bacteria in the body.
[0012] Compared with the prior art, the present invention has the following beneficial effects:
[0013] 1. Significant synergistic antibacterial effect: This invention is the first to discover and confirm that when the Cu:Fe molar ratio is 8:2, there is an optimal synergistic effect between Cu and Fe. Through extensive experimental screening, Cu8Fe2 NCs showed an antibacterial rate of up to 98.1% against MRSA, which is much higher than that of pure Cu NCs (67.3%) and pure Fe NCs (1.2%).
[0014] 2. A Clear Dual Synergistic Antibacterial Mechanism: This invention reveals that the antibacterial mechanism of Cu8Fe2 NCs is a dual synergistic "physical-chemical" damage mechanism. First, the positively charged nanomaterials bind to the negatively charged bacteria through electrostatic adsorption, directly disrupting the cell membrane integrity and leading to K... + And leakage of vital substances such as DNA (physical damage). Secondly, the peroxide groups on the material surface can act as an endogenous source of H2O2, in Fe 2+ Under Fenton catalysis, a large number of ·OH radicals are generated; at the same time, Cu is released. 2+ / Cu + It can also participate in Fenton-like reactions and mutually promote the Fe ion cycle, triggering severe oxidative stress (chemical damage) within bacteria. This multi-target attack mode makes it difficult for bacteria to develop drug resistance through a single mutation.
[0015] 3. Excellent biocompatibility: In vitro and in vivo safety evaluation results show that Cu8Fe2 NCs have no significant toxicity to mammalian cells (such as A549) and erythrocytes at an effective antibacterial concentration (120 μg / mL), and do not cause pathological damage to major organs in mice (at doses up to 50 mg / kg), demonstrating good biocompatibility and laying the foundation for its clinical application. Attached Figure Description
[0016] Figure 1 This is a transmission electron microscope (TEM) image of copper-iron nanocrystals.
[0017] Figure 2 It is FTIR of copper-iron nanocrystals.
[0018] Figure 3 It is Cu with different Cu-Fe ratios x Fe y Inhibitory effect of NCs on methicillin-resistant Staphylococcus aureus.
[0019] Figure 4 The study investigated the antibacterial effects of different concentrations of copper-iron nanocrystals on methicillin-resistant Staphylococcus aureus.
[0020] Figure 5 Different concentrations of copper-iron nanocrystals are used to target the K+ in methicillin-resistant Staphylococcus aureus cells. ＋ Ion leakage diagram.
[0021] Figure 6 This diagram illustrates the generation of reactive oxygen species in methicillin-resistant Staphylococcus aureus (MRSA) under the influence of copper-iron nanocrystals of different concentrations.
[0022] Figure 7 This is a safety evaluation diagram of different concentrations of copper-iron nanocrystals on A549 cells in live-dead cell experiments.
[0023] Figure 8 This is a safety evaluation chart of different concentrations of copper-iron nanocrystals on the organ indices of normal mice.
[0024] Figure 9 This shows the changes in body weight among different groups of mice.
[0025] Figure 10 This is an analysis of bacterial colony results in organs of different groups of mice. Detailed Implementation
[0026] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0027] Example 1
[0028] 1) Preparation of copper-iron nanocrystals
[0029] First, polyvinylpyrrolidone (PVP) was dissolved in distilled water. Then, an aqueous solution of CuCl₂·2H₂O and FeCl₂·4H₂O (molar ratio 8:2) was slowly poured into the PPVP distilled water solution, and the mixture was stirred rapidly. NaOH and H₂O₂ aqueous solutions were then added, and the mixture was stirred for 6 hours. The product was collected by centrifugation and washing. Finally, the final copper-iron nanocrystalline material was obtained by freeze-drying. It was diluted with PBS to create different concentration gradients for later use.
[0030] 2) Structural characterization of copper-iron nanocrystals
[0031] The morphology of the material was observed using a transmission electron microscope (TEM, 2000FX, JEOL, Japan). The functional groups of the material were further determined using a Fourier transform infrared spectroscopy (Thermo Scientific Nicolet iS2, USA).
[0032] 3) Cu with different Cu-Fe ratios x Fe y Inhibitory effect of NCs on methicillin-resistant Staphylococcus aureus
[0033] By measuring Cu with different Cu-Fe ratios x Fe y The antibacterial properties of each group of samples were evaluated by the inhibitory effect of NCs on methicillin-resistant Staphylococcus aureus.
[0034] Example 2
[0035] 1) Antibacterial effect of different concentrations of copper-iron nanocrystals on methicillin-resistant Staphylococcus aureus
[0036] Methicillin-resistant Staphylococcus aureus (MRSA) USA 300 was selected from the College of Veterinary Medicine, Jilin University. After overnight culture, OD was adjusted. 600nm =0.1, and inoculated into TSB liquid medium containing 0, 30, 60, 120, and 240 μg / mL copper-iron nanocrystal solutions (with sterile PBS as a control). Then incubated at 37°C for 4 h. Inoculated onto solid medium using the dilution plating method, and counted after single colonies formed.
[0037] 2) The effect of different concentrations of copper-iron nanocrystals on potassium in methicillin-resistant Staphylococcus aureus cells ＋ Ion leakage
[0038] OD 600nm Methicillin-resistant Staphylococcus aureus (MRSA) at a concentration of 0.1 μg / mL was inoculated into TSB liquid medium containing 0, 30, 60, 120, and 240 μg / mL copper-iron nanocrystals (with sterile PBS as a control). The cultures were incubated at 37°C for 4 hours. After centrifugation, the bacterial suspension was collected and centrifuged again. The potassium ion concentration (K ions) in the supernatant was determined using a potassium ion assay kit. ＋ The concentration of ).
[0039] 3) Effects of different concentrations of copper-iron nanocrystals on the generation of reactive oxygen species in methicillin-resistant Staphylococcus aureus.
[0040] Bacterial suspensions were mixed with copper-iron nanocrystal solutions of 0, 30, 60, 120, and 240 μg / mL, and incubated at 37°C for 4 hours. The bacterial cell pellets were collected by centrifugation, and 20 μL of 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA, 10 mol / L) was added to each pellet. After incubation in the dark for 10 min, the pellets were collected by centrifugation and washed twice with PBS buffer to remove residual fluorescent dye. Finally, the luminescence of each group of bacteria was recorded using a fluorescence microscope.
[0041] Example 3
[0042] 1) Safety evaluation of different concentrations of copper-iron nanocrystals in A549 cell live-dead cell experiments
[0043] A549 cells were cultured at 37°C and 5% CO2 under saturated humidity for 48 h. They were then digested with 0.25% trypsin, and digestion was terminated by adding antibiotic-free DMEM medium containing 10% fetal bovine serum. After resuspending the cells, cell counting was performed under an optical microscope. The cell suspension was seeded into 96-well cell culture plates (cell density: 2.5 × 10⁵ cells / mL) and cultured overnight. Different concentrations of copper-iron nanomaterials (0.5, 1, 2, and 4 mg / mL) were added to the cells for 5 h. The cell pellet was collected by centrifugation at 10,000 rpm for 3 min and co-stained with propidium iodide (PI) and SYTO9 fluorescent dye for 30 min in the dark. After staining, the cell solution was washed three times with PBS to remove excess dye. For each treatment condition, live and dead cells were observed and imaged using a Zeiss confocal laser scanning microscope.
[0044] 2) Safety evaluation of different concentrations of copper-iron nanocrystals on organ indices in normal mice
[0045] After one week of acclimatization, all mice were randomly divided into four groups. Copper-iron nanomaterials were administered via tail vein injection at doses of 0, 5, 10, and 15 mg / kg, respectively, with an injection volume of 200 μL every 24 hours for three consecutive days. An equal volume of PBS was used as a blank control. Mice were observed for four days after administration, and clinical symptoms such as body weight, mental status, food excretion, coat luster, and mortality were recorded for each group. Seven days later, heart, liver, spleen, lungs, and kidneys were collected to analyze organ indices in different groups.
[0046] Example 4
[0047] 1) Changes in body weight of mice in different groups
[0048] Twenty-four mice were randomly divided into four groups of six each: a normal control group, a copper-iron nanocrystal treatment group, a vancomycin treatment group, and an infection group. After fixing the mice, 1×10⁻⁶ mg / L was injected via the tail vein. 8 A bacterial suspension of CFU / mL was prepared, and the mice were weighed once. Twenty-four hours later, the infection group and the treatment group were injected with the same dose and concentration of PBS solution via tail vein. Their clinical response was observed, and the weight of the mice was recorded every 24 hours. The mice were dissected four days after administration for subsequent experiments.
[0049] 2) Analysis of bacterial colony results of organs from different groups of mice
[0050] Under aseptic conditions, mice were dissected and their organs were removed and weighed. The organs were then placed in a sterile grinding tube with PBS and ground thoroughly in a multi-sample grinder. The homogenate was then serially diluted 100-fold, and 10 μl of the sample was dropped into a solid culture dish and incubated at 37°C for organ colony counting.
Claims
1. A copper-iron nanocrystalline material, characterized in that, The copper-iron nanocrystalline material is a copper-iron composite oxide nanocrystalline material, wherein the molar ratio of copper to iron is 8:2, and the copper-iron nanocrystalline material contains two crystal phase structures: CuO and Fe3O4.
2. The copper-iron nanocrystalline material according to claim 1, characterized in that, The surface of the copper-iron nanocrystalline material is modified with a stabilizer containing peroxy groups.
3. The copper-iron nanocrystalline material according to claim 2, characterized in that, The stabilizer is polyvinylpyrrolidone, and the peroxide group is derived from the oxidant used in the preparation process.
4. The copper-iron nanocrystalline material according to claim 1, characterized in that, The copper-iron nanocrystalline material has a rod-like structure with an average diameter of 50-150 nm.
5. The method for preparing the copper-iron nanocrystalline material according to any one of claims 1-4, characterized in that, Copper-iron nanocrystals were synthesized by a one-pot method, the preparation steps of which include: Dissolve polyvinylpyrrolidone (PVP) in distilled water; Add aqueous solutions of CuCl2·2H2O and FeCl2·4H2O, and stir until completely dissolved; Add NaOH aqueous solution and H2O2 aqueous solution to the mixture and stir rapidly to react; The product was collected by centrifugation and washing, and then obtained copper-iron nanocrystalline materials by freeze drying.
6. The application of the copper-iron nanocrystalline material according to any one of claims 1-4, characterized in that, The copper-iron nanocrystalline material is used to inhibit methicillin-resistant Staphylococcus aureus (MRSA), with an optimal inhibitory concentration of 120 μg / mL.
7. The application of the copper-iron nanocrystalline material according to any one of claims 1-4, characterized in that, The copper-iron nanocrystalline material is used to prepare drugs for treating infectious diseases caused by methicillin-resistant Staphylococcus aureus (MRSA), including pneumonia, wound infections, and myocarditis.
8. The application of the copper-iron nanocrystalline material according to any one of claims 1-4, characterized in that, Used to prepare drugs for treating bacteremia.