Application of a composite nano-system with external field response characteristics in preparation of a drug for treating Alzheimer's disease

Abstract

The application belongs to the field of biological medicine, and particularly relates to application of a composite nano system with external field response characteristics in preparation of a drug for treating Alzheimer's disease. The composite nanoparticles of the application can effectively penetrate the blood-brain barrier and enrich in the hippocampal brain area. Under the regulation of an external magnetic field, the composite nanoparticles produce a local magnetic-electric coupling effect. After continuous intervention, cognitive dysfunction can be significantly improved, and hippocampal neurons can be effectively protected. The system proves that remote magnetic field stimulation mediated by the composite nano system can improve Alzheimer's disease by relieving neurotoxicity, protecting hippocampal neurons, relieving chronic neuroinflammation, and especially removing beta amyloid (A beta) plaque.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine, specifically relating to the application of a composite nanosystem with external field response characteristics in the preparation of drugs for treating Alzheimer's disease. Background Technology

[0002] Alzheimer's disease is the most common neurodegenerative disease in the elderly population. Its pathological features include senile plaques formed by the deposition of β-amyloid protein (Aβ), neurofibrillary tangles caused by hyperphosphorylation of tau protein, and widespread neuronal loss and synaptic dysfunction. Currently, first-line clinical drugs such as cholinesterase inhibitors and NMDA receptor antagonists can only temporarily relieve symptoms and cannot stop or reverse the disease progression. More seriously, the existence of the blood-brain barrier makes it difficult for more than 98% of small molecule drugs and almost all large molecule drugs to enter the brain parenchyma, severely limiting the efficacy of treatment. Summary of the Invention

[0003] To address at least some of the technical problems existing in the prior art, this invention provides a remote, precise neuromodulation strategy based on composite nanoparticles for the treatment of Alzheimer's disease. Specifically, this invention includes the following:

[0004] In a first aspect, the present invention provides the application of a composite nanosystem with external field response characteristics in the preparation of a drug for treating Alzheimer's disease, wherein the composite nanosystem comprises an external magnetic field and composite nanoparticles, the composite nanoparticles comprising a core containing a cobalt spinel-type oxide phase and a shell containing a bismuth rhombic perovskite-type oxide phase.

[0005] In some embodiments, according to the application described in the present invention, the composite nanoparticles comprise Co, Bi, and Fe, wherein the cobalt element in the nanoparticles is mainly present in the spinel lattice, and the bismuth element is mainly present in the perovskite lattice.

[0006] In some embodiments, according to the application described in the present invention, the X-ray powder diffraction pattern of the core of the composite nanoparticle includes characteristic peaks at 2θ = 30.1°, 35.5°, 43.1°, 53.4°, 57.0°, and 62.6°, and the X-ray powder diffraction pattern of the shell of the composite nanoparticle includes characteristic peaks at 2θ = 22.6°, 31.7°, 35.3°, 45.0°, 51.5°, and 55.7°.

[0007] In some embodiments, according to the application described in the present invention, the composite nanoparticles include optional modified or altered materials selected from at least one of organic materials, inorganic materials, and organic-inorganic hybrid materials.

[0008] In some embodiments, according to the application described in the present invention, the particle size of the composite nanoparticles is 50-500 nm.

[0009] In some embodiments, according to the application described in this invention, the preparation of the composite nanoparticles includes the following steps: (1) Preparation of a core containing a cobalt spinel-type oxide phase; (2) A precursor solution containing a bismuth source is used to form a shell covering the surface of the core.

[0010] In some embodiments, according to the application described in the invention, a shell covering the core is formed on the surface of the core by methods including spin coating, dip-coating, sol-gel, or hydrothermal / solvothermal methods.

[0011] In some embodiments, according to the application described in the present invention, the composite nanoparticles are further treated with an external magnetic field after step (2).

[0012] In some embodiments, according to the application described in the present invention, the dosage form of the drug includes injections, solutions, transdermal patches, implants, nasal preparations or sublingual tablets, preferably injections, and even more preferably suspensions for injection or lyophilized powders for injection.

[0013] A second aspect of the present invention provides the application of composite nanoparticles and magnetic field therapy devices in the preparation of products for the combined treatment of Alzheimer's disease, wherein the composite nanoparticles are the composite nanoparticles mentioned above.

[0014] In some embodiments, according to the application described in the present invention, the magnetic field therapy device is provided with a magnetic field generating unit configured to generate a magnetic field of effective magnetic field strength.

[0015] The composite nanoparticles of this invention can effectively penetrate the blood-brain barrier and accumulate in the hippocampus. Under external magnetic field modulation, the composite nanoparticles generate a local magnetoelectric coupling effect. With continuous intervention, they can significantly improve cognitive dysfunction and effectively protect hippocampal neurons. This invention systematically demonstrates that remote magnetic field stimulation mediated by the composite nanosystem can improve Alzheimer's disease by alleviating neurotoxicity, protecting hippocampal neurons, and particularly clearing Aβ plaques. Attached Figure Description

[0016] Figure 1 The characterization of the composite nanoparticles prepared according to the present invention is shown.

[0017] Figure 2 This demonstrates that the composite nanoparticles prepared according to the present invention exhibit excellent biocompatibility and low cytotoxicity.

[0018] Figure 3 The invention demonstrates that the composite nanoparticles prepared in this invention have a protective effect on neurons.

[0019] Figure 4 The in vivo imaging results of the composite nanoparticles prepared according to the present invention are shown.

[0020] Figure 5 The results of the shuttle experiment behavioral tests for each treatment group are shown.

[0021] Figure 6 The results of the Y-maze test for each treatment group are shown.

[0022] Figure 7 The results of Aβ staining of the cerebral cortex for each treatment group are shown.

[0023] Figure 8 The expression levels of Aβ and ibal1 in the cerebral cortex and hippocampus of each treatment group are shown.

[0024] Figure 9 The in vivo biocompatibility of the magnetoelectric nanoparticles was demonstrated. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Application of composite nanosystems with external field responsiveness in the preparation of drugs for treating Alzheimer's disease In one aspect, the present invention provides the use of a composite nanosystem with external field response characteristics in the preparation of a medicament for treating Alzheimer's disease, and particularly provides the use of composite nanoparticles treated or stimulated by an external magnetic field in the preparation of a medicament for treating Alzheimer's disease, wherein the composite nanoparticles comprise a core containing a cobalt spinel-type oxide phase and a shell containing a bismuth rhombic perovskite-type oxide phase.

[0029] The composite nanoparticles of the present invention have magnetoelectric conversion properties. After being treated or stimulated by a magnetic field, they generate an output voltage. "Magnetic field treatment or stimulation" means that the core structure in the core-shell structure of the nanoparticles of the present invention can generate relative displacement under the action of an applied external magnetic field. That is, when the core structure is magnetized in the magnetic field, it will elongate or shorten along the magnetization direction, while the shell structure can convert the mechanical energy brought by the core structure into electrical energy, that is, generate an output voltage. Ultimately, the whole structure plays a role in treating or improving Alzheimer's disease.

[0030] In a preferred embodiment, the magnetic field treatment comprises treating the composite nanoparticles with a magnetic field strength of 0.01-300 mT and a frequency of 0.1-100 kHz. The magnetic field strength is also preferably 0.1-200 mT, more preferably 0.5-100 mT, more preferably 0.5-50 mT, and most preferably 0.5-10 mT, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10 mT. The frequency is also preferably 0.5-50 kHz, more preferably 0.5-10 kHz, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 kHz. The processing time is 0.5-120 min, preferably 1-100 min, even more preferably 5-90 min, and even more preferably 10-60 min, for example 10, 20, 30, 40, 50, 60 min.

[0031] In one specific embodiment, the composite nanoparticles are cobalt ferrite-bismuth ferrite nanoparticles. In this embodiment, the X-ray powder diffraction pattern of the core (cobalt ferrite) of the composite nanoparticles contains characteristic peaks at 2θ = 30.1°, 35.5°, 43.1°, 53.4°, 57.0°, and 62.6°, and the X-ray powder diffraction pattern of the shell (bismuth ferrite) of the composite nanoparticles contains characteristic peaks at 2θ = 22.6°, 31.7°, 35.3°, 45.0°, 51.5°, and 55.7°. Measurement conditions: Cu Kα, λ = 0.15406 nm.

[0032] It is understood that the composite nanoparticles of the present invention may or may not contain dopants. When dopants are present, the dopants include, but are not limited to, at least one of carbon, nitrogen, phosphorus, sulfur, silicon, aluminum, iron, titanium, nickel, manganese, copper, silver, and zinc, thereby improving the piezoelectric and / or magnetoelectric response properties of the composite nanoparticles. It is understood that any of the above-mentioned dopants or other coating structures may also be contained between the shell structure and the core structure, in the outer layer of the shell structure, and within the core structure to improve the piezoelectric and / or magnetoelectric response properties of the nanoparticles. The coating structure may be a coating containing modified / modified materials, examples of which include, but are not limited to, at least one of organic materials, inorganic materials, and organic-inorganic hybrid materials, such as conductive polymers, biodegradable polymers, hydrogels, polylactic acid, polycaprolactone, polyvinylidene fluoride, polytetrafluoroethylene, collagen, gelatin, chitosan, alginate, hyaluronic acid, or heparin, etc.

[0033] In this invention, the average particle size of the cobalt ferrite-bismuth ferrite nanoparticles is 50-500 nm, preferably 200-400 nm, even more preferably 200-260 nm, and further 220-240 nm, for example 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240 nm.

[0034] This invention does not impose any particular limitation on the preparation of composite nanoparticles. Shell structures with piezoelectric properties and core structures with magnetoelectric response properties can be prepared using methods known in the art (such as WO2025195465A1).

[0035] In this invention, improving or treating Alzheimer's disease includes at least one of the following: (1) Reduce the amount of Aβ; (2) Improve cognitive dysfunction; (3) Reduce neurotoxicity.

[0036] In one aspect, the present invention further provides the application of composite nanoparticles and magnetic field therapy devices in the preparation of products for the combined treatment of Alzheimer's disease.

[0037] In any of the above embodiments, Alzheimer's disease is improved or treated by administering a therapeutically effective amount of composite nanoparticles and a magnetic field of 0.01-300 mT to subjects in need.

[0038] As used in this invention, the term "subject" refers to any animal (such as a mammal), including but not limited to humans, non-human primates, rodents, and the like who are about to receive a specific treatment. Generally, "subject" and "patient" are used interchangeably in this invention, both referring to the subject of the study.

[0039] The terms “give,” “apply,” or “administer” used in this invention are used interchangeably and refer to the introduction of composite nanoparticles by implantation, absorption, uptake, injection, inhalation, or other means.

[0040] As used herein, the term "effective amount" refers to the amount of a drug or pharmaceutical agent that elicits a biological or pharmaceutical response in a tissue, system, animal, or human, as sought by, for example, an investigator or clinician. Furthermore, the term "therapeutic effective amount" refers to the amount that causes improved treatment, cure, prevention, or reduction of disease, symptom, or side effects, or reduces the rate of progression of the disease or condition, compared to a corresponding subject who did not receive that amount. The term also includes, within its scope, amounts that effectively enhance normal physiological function. Generally, the effective amount as used herein varies depending on various factors, such as the given drug or compound, pharmaceutical formulation, route of administration, type of disease or symptom, subject being treated, etc., but can still be routinely determined by those skilled in the art.

[0041] The therapeutic dosage of this invention can vary widely. Generally speaking, the dosage of the composite nanoparticles used in this invention is well known to those skilled in the art. The dosage can be administered as a single dose or in several doses, such as two, three, or four doses. The administered dosage is within the predictable range for clinicians or laboratory personnel, and can be appropriately adjusted, for example, through efficacy and safety testing, to obtain the optimal dosage.

[0042] In this invention, the total dose required for treatment can be divided into multiple administrations or administered as a single dose. Furthermore, the composite nanoparticles of this invention can be used alone, or in combination with other therapeutic or symptomatic drugs, with dosage adjustments.

[0043] There are no particular restrictions on the application method of the composite nanoparticles of the present invention. Representative application methods include, but are not limited to, intramuscular injection, intravenous injection, intravenous drip, or intraperitoneal injection.

[0044] In the combined application, the specific type of product is not particularly limited. It can be a medical device or medical apparatus for treating Alzheimer's disease, which includes the magnetic field therapy device of the composite nanoparticles of the present invention. The magnetic field therapy device is provided with a magnetic field generating unit, which is configured to generate a magnetic field with a magnetic field strength of 0.01-300 mT and a frequency of 0.1-100 kHz.

[0045] Example I. Experimental Methods 1. Preparation of composite nanomaterials (CFO-BFO MENs) 1.1 Preparation of CoFe2O4 nanoparticles CoFe2O4 nanoparticles were prepared by a hydrothermal method using ethylene glycol, diethylene glycol, FeCl3•6H2O, and CoCl3•6H2O as raw materials. During the preparation process, the proportions of the added mineralizing agents FeCl3•6H2O and CoCl3•6H2O were adjusted to obtain CoFe2O4 samples with stable morphology, particle size, and magnetic properties.

[0046] 1.2 Preparation of BiFeO3 nanoparticles BiFeO3 nanoparticles were synthesized from Bi(NO3)3•5H2O, Fe(NO3)3•9H2O, glacial acetic acid, and ethylene glycol using a sol-gel process.

[0047] 1.3 Preparation of core-shell nanostructured composite material CoFe2O4-BiFeO3 Core-shell nanostructures consist of an inner core and an outer shell. Specifically, CoFe2O4-BiFeO3 is a magnetoelectric composite material. The inner core is made of ferromagnetic CoFe2O4, while the outer shell is made of ferroelectric BiFeO3, meaning that a BiFeO3 shell is coated onto the outer layer of CoFe2O4 nanoparticles. First, high-performance CoFe2O4 nanoparticles are prepared via a hydrothermal method. Then, a BiFeO3 precursor solution is prepared separately. The CoFe2O4 nanoparticles are then placed in the BiFeO3 precursor solution, and ultrasonic vibration is used to reduce powder agglomeration, ensuring uniform dispersion in the solution. After drying to form a gel, heat treatment is performed to obtain a well-crystallized BiFeO3 shell on the outer layer of the CoFe2O4 nanoparticles. In other words, a core-shell nanostructure composite material is obtained by coating the surface of the prepared CoFe2O4 nanoparticles with a BiFeO3 shell using a sol-gel method.

[0048] 2. Material Characterization The morphology and size of the materials were observed using scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. Elemental analysis of CFO-BFO MENs was performed using energy dispersive spectroscopy. X-ray diffraction (XRD) patterns of CFO NPs, BFO NPs, and CFO-BFO MENs were recorded on a Bruker-AXS D8 Advance powder diffractometer. Absorption spectra were measured using a UV-3600 spectrophotometer.

[0049] 3. Biosafety assessment Biosafety was assessed using the CCK-8 assay. Neuronal cells were co-cultured with different concentrations of CFO-BFO MENs in 96-well plates for 24 h, and biosafety was then assessed. Neuronal cells were placed under different magnetic field strengths for 30 min, and analyzed after 24 h. Subsequently, 20 μL of Cell Counting Kit-8 and 180 μL of culture medium were added to each well, and the samples were incubated at 37°C in the dark for 1 h. The samples were then analyzed using a microplate reader at 450 nm.

[0050] 4. Cell uptake experiment FITC-conjugated CFO-BFO MENs were co-cultured with neurons for 0, 8, 12, and 24 h. The neurons were then washed with PBS to remove extracellular CFO-BFO MENs, and the mean fluorescence intensity was measured by flow cytometry.

[0051] 5. In vitro experiments 5.1 Main materials: Cell line: HT22 mouse hippocampal neuron cell line; Commercially available Aβ protein: Aβ 1-42 Freeze-dried powder (purity ≥ 95%); Composite nanomaterials: The concentration of the PBS solution containing composite nanoparticles was 30 μg / mL; 96-well plate, incubator, CCK-8 kit.

[0052] 5.2 Experimental Grouping Blank control group: complete culture medium; Aβ treatment group: Aβ-containing groups were added separately. 1-42 Culture medium for oligomers; Treatment group: A solution containing composite nanoparticles was added, and magnetic field stimulation was applied. Processing time: Set time gradients of 24 h and 48 h; Each group has 3-6 duplicate holes, and each group is repeated independently at least 3 times.

[0053] 5.3 Methods for detecting neurotoxicity levels Cell viability assay (CCK-8): HT22 cells were seeded in 96-well plates (5 × 10⁻⁶ cells / well). 3 Cells were incubated in each well overnight, and the old medium was discarded. Culture medium containing Aβ and solutions containing composite nanoparticles were added according to the groups, and the cells were cultured for 24 h. 10 μL of CCK-8 solution was added to each well, and the cells were incubated for 1-2 h. The absorbance at 450 nm was measured using a microplate reader, and cell viability was calculated.

[0054] 6. In vivo experiments 6.1 Construction and Grouping of AD Mouse Model Animal models: 5×FAD mice and littermate wild-type (WT) controls. Housing environment: SPF grade, 12h / 12h light / dark cycle, free access to food and water.

[0055] The groups are as follows: WT control group: wild-type mice + tail vein injection of physiological saline / solvent; WT treatment group: wild-type mice were injected with composite nanoparticles (20 mg / kg, once every 3 days) via the tail vein, and subjected to external magnetic field stimulation for 30 min daily; AD control group: 5×FAD mice + tail vein injection of physiological saline / solvent.

[0056] AD treatment group: 5×FAD mice + tail vein injection of composite nanoparticles (20 mg / kg, once every 3 days), plus external magnetic field stimulation for 30 min every day.

[0057] Administration method: Fix the mouse, wipe the tail with 75% alcohol to dilate blood vessels, and slowly inject through the lateral tail vein using a syringe.

[0058] 6.2 In vivo imaging To monitor the distribution of fluorescently labeled composite nanoparticles in the brain, mice were anesthetized with isoflurane inhalation at fixed time points of 6 h, 12 h, 24 h, and 48 h after the first injection. The mice were then placed in a prone position in the dark chamber of a small animal in vivo imaging system. Excitation / emission wavelengths were set, and bright-field and fluorescence images were automatically captured using exposure.

[0059] 6.3 Behavioral Testing All tests were completed within a fixed time period, and the participants were blinded during the process.

[0060] 6.3.1 Shuttle Experiment (Active Avoidance Response) The shuttle box consisted of two chambers, one bright and one dark, with an electrically powered grid at the bottom and equipped with sound / light stimulation devices. On the first day, mice were placed in the shuttle box and allowed to explore freely for 5 minutes without any stimulation. On the second day, 20 trials were conducted, each with a 30-second interval. Sound and light stimulation was applied for 10 seconds. If the mouse shuttled to the opposite side within 10 seconds, it was considered active avoidance, and the sound and light stimulation was immediately terminated. If the mouse did not shuttle within 10 seconds, a foot shock (0.15 mA, lasting 5 seconds) was applied; if the mouse shuttled during this time, it was considered passive avoidance; otherwise, it was considered avoidance failure.

[0061] Observation indicators: Test duration: The experimental time spent by an animal in the test chamber completing all tests (20 cycles), reflecting the animal's reaction speed and behavioral ability. The shorter the total experimental time, the better the animal's memory. The shorter the incubation period, the faster the reaction and the better the animal's memory. Number of times an animal actively avoids another animal: This reflects the animal's learning ability; the more times an animal avoids another animal, the stronger its memory.

[0062] 6.3.2 Y-maze test (Y-maze new arm recognition experiment to evaluate spatial working memory) The Y-maze consists of three sections measuring 35×8×18 cm with an angle of 120 degrees between them. 3 The Y-maze consisted of several arms. Before the experiment, mice were placed in the experimental environment for 3 days to acclimatize, during which they underwent 10 minutes of open-field exploration training daily to reduce environmental stress. One hour before the experiment, the mice were transferred from their cages to the experimental room to further acclimatize. The Y-maze was cleaned before the experiment to ensure no odor residue remained. Initially, two arms of the Y-maze were opened, and the third arm was closed as a new arm. The mice were placed in the central area of ​​the Y-maze and allowed to freely explore the two open arms for 10 minutes. After the experiment, the mice were returned to their cages, and the maze was cleaned for the next mouse. Two hours after the acclimatization phase, the mice were placed back in the central area of ​​the Y-maze, this time with all three arms open, allowing them to freely explore for 5 minutes. The number of times they entered each arm and the time spent in each arm were recorded, with particular attention paid to their exploration behavior in the new arm. After the experiment, the mice were returned to their cages, and the maze was cleaned. Finally, the total number of times the mice entered each arm and the total time spent in each arm were counted, and the percentage of time spent exploring the new arm was calculated to assess their ability to explore the new environment.

[0063] 6.4 Brain tissue sampling and frozen section preparation After the behavioral studies, mice were deeply anesthetized with isoflurane by inhalation, and the heart was exposed via thoracotomy. Pre-cooled PBS (approximately 30 mL) was perfused into the left ventricle, followed by perfusion with 4% paraformaldehyde (PFA, approximately 30 mL) until the limbs and liver hardened. Brain tissue was completely removed and fixed overnight in 4% PFA at 4°C. It was then sequentially transferred to 20% and 30% sucrose solutions (prepared with PBS) and allowed to settle at 4°C (approximately 24-48 h). OCT embedding was performed, and coronal serial sections were cut using a cryostat to a thickness of 10 μm. Sections containing the cerebral cortex and hippocampus were collected, and the experimental groups were as follows: Group 1: Used for double staining of Aβ+Iba1 in the cerebral cortex (immunofluorescence); Group 2: Used for double staining of Aβ+Iba1 in the hippocampus (immunofluorescence).

[0064] 6.4.1 Immunofluorescence double staining of Aβ and Iba1 in the cerebral cortex / hippocampus After sectioning and rinsing, antigen retrieval is performed as above (or according to antibody requirements). After blocking, incubate with primary antibody, rinse, and then add the appropriate fluorescent secondary antibody mixture; incubate at room temperature in the dark for 2 hours. Rinse, and counterstain cell nuclei with DAPI. After rinsing, mount the slides and mount with anti-fluorescence quenching mounting medium. Take high-power field-view images (e.g., 20× or 40×) of the cerebral cortex and hippocampal CA1 / CA3 / DG regions. Z-Stack the images to ensure three-dimensional reconstruction.

[0065] 6.4.2 Quantitative Analysis (ImageJ / Fiji): Aβ patches: Delineate the red fluorescence threshold and measure the patch area and number; Iba1+ microglia: Count the number of green cells per unit area and analyze their distance / colocalization relationship with Aβ plaques (Pearson correlation coefficient can be used); Calculate microglia morphological parameters (such as cell size and protrusion length) and green fluorescence threshold to reflect activation status.

[0066] II. Experimental Results 1. Characterization of CFO-BFO MENs Core-shell structured CFO-BFO magnetostrictive piezoelectric NPs (CFO-BFO MENs) were prepared by coating the surface of a BFO precursor onto a CFO core using a hydrothermal and sol-gel method. According to scanning electron microscopy (SEM) images, the final size of the coated CFO-BFO MENs was 200-250 nm. Figure 1 a, b). TEM images show that the CFO core is encased in a layer of BFO within the CFO-BFO MENs (e.g., Figure 1 As shown in c), this indicates that CFO-BFO MENs possess a core-shell structure. The elemental distribution was evaluated using energy dispersive spectroscopy (EDS). Bi, Co, and Fe were all present in the CFO-BFO MENs, with Bi being uniformly distributed around the CFO core. Figure 1 d) further confirmed the core-shell structure of CFO-BFO MENs. X-ray diffraction (XRD) patterns revealed a cubic spinel structure of CoFe2O4 and a rhombic perovskite phase of BiFeO3. Both of these structures are present in CFO-BFO MENs. Figure 1 f shows the UV-Vis absorption spectrum of CFO-BFO MENs. The degradation of Rhodamine B by CFO-BFO MENs under the action of a magnetic field demonstrates the piezoelectric and magnetoelectric coupling effects of the CFO-BFO samples.

[0067] Furthermore, in vitro biocompatibility assessments showed that the composite nanoparticles of this invention exhibited excellent biocompatibility and low cytotoxicity at 30 μg / mL, a magnetic field of 1 kHz, 1.5 mT, and 30 min. Figure 2 ).

[0068] 2. Protective effect of composite nanoparticles on neurons The model group showed a significant decrease in cell viability compared to the control group, indicating a significant increase in neurotoxicity levels within HT22 (neurons) cells induced by Aβ protein. After treatment with composite nanoparticles, the neurotoxicity levels within HT22 (neurons) cells induced by Aβ protein were significantly reduced, indicating that the composite nanoparticles have a protective effect on neurons. Figure 3 ).

[0069] 3. Live imaging results ICG-CFO-BFO MENs, conjugated with ICG fluorescence, were injected into mice via the tail vein. In vivo imaging revealed that the CFO-BFO MENs could remain in the brains of AD mice for more than 48 hours. The lesions in AD mice were mainly in the hippocampus and cortex. The hippocampus is rich in neurons and microglia, and in this embodiment, the nanoparticles were found to be mainly concentrated in the hippocampal region. Figure 4 ).

[0070] 4. Behavioral test results 4.1 Shuttle Experiment After treating AD mice with CFO-BFO MENs for 12 weeks, behavioral tests, including a shuttle test, were performed. The results showed that after 12 weeks of CFO-BFO MENs treatment, the time to complete the behavioral test in AD mice significantly decreased, the latency period significantly decreased, and the number of active avoidance attempts significantly increased. This indicates that CFO-BFO MENs treatment significantly improved reaction speed, behavioral ability, memory, and learning ability in AD mice. Figure 5 See Table 1 below for details.

[0071] Table 1 4.2 Y-maze test After treating AD mice with CFO-BFO MENs for 12 weeks, the mice were subjected to a Y-maze test. In the diagram, N represents the new arm; a longer N indicates more explorations of new walls, suggesting stronger spatial memory and cognitive abilities in the mouse. After 12 weeks of treatment with CFO-BFO MENs, the AD mice showed significant enhancement in brain learning behavior and recognition abilities. Figure 6 ).

[0072] 4. Deposition of Aβ protein in the mouse cerebral cortex After treating AD mice with CFO-BFO MENs for 12 weeks, Aβ staining was performed on the cerebral cortex of the mice. The results showed that after 12 weeks of treatment with CFO-BFO MENs, the deposition of Aβ protein, which is closely related to Alzheimer's disease, in the cerebral cortex of AD mice was significantly reduced. Figure 7 ).

[0073] 5. Expression levels of Aβ and ibal1 in the mouse cerebral cortex and hippocampus After 12 weeks of treatment with CFO-BFO MENs in AD mice, Aβ and ibal1 (microglia activation) staining was performed on the cerebral cortex and hippocampus. Following 12 weeks of CFO-BFO MENs treatment, the deposition of Aβ protein closely associated with Alzheimer's disease and the expression of ibal1 in the cerebral cortex and hippocampus of AD mice were significantly reduced. Figure 8 ).

[0074] 6. In vivo biosafety Figure 9 The results of safety tests are shown, indicating that the magnetoelectric nanoparticles (MENs) have good biocompatibility in vivo at conventional dosages, without causing significant organ damage, inflammatory stress, or hemolytic reactions, and no pathological changes were observed in the pathological sections of major organs.

[0075] Based on the above results, after 12 weeks of treatment in AD mice with CFO-BFO MENs, the levels of Aβ deposition and Iba-1 positive microglia activation in the hippocampal cortex and hippocampus significantly decreased. Simultaneously, the microglia morphology transformed from activated amoeboid to resting branched structures, indicating that this nanomaterial can not only effectively inhibit the accumulation of Aβ plaques but also alleviate neuroinflammatory responses in the brains of AD model mice, reshaping microglia functional homeostasis. These results further suggest that CFO-BFO MENs, under long-term intervention, may exert a dual ameliorative effect on the neuropathological characteristics of Alzheimer's disease by inhibiting pathological protein deposition and regulating immune cell activity, suggesting its promising therapeutic potential in delaying or intervening in AD progression.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of composite nanosystems with external field response characteristics in the preparation of drugs for treating Alzheimer's disease, characterized in that, The composite nanosystem includes an external magnetic field and composite nanoparticles, wherein the composite nanoparticles include a core containing a cobalt spinel-type oxide phase and a shell containing a bismuth rhombic perovskite-type oxide phase.

2. The application according to claim 1, characterized in that, The composite nanoparticles contain Co, Bi, and Fe. Cobalt is mainly found in the spinel lattice, and bismuth is mainly found in the perovskite lattice.

3. The application according to claim 1, characterized in that, The X-ray powder diffraction pattern of the core of the composite nanoparticle contains characteristic peaks at 2θ = 30.1°, 35.5°, 43.1°, 53.4°, 57.0°, and 62.6°, and the X-ray powder diffraction pattern of the shell of the composite nanoparticle contains characteristic peaks at 2θ = 22.6°, 31.7°, 35.3°, 45.0°, 51.5°, and 55.7°.

4. The application according to claim 1, characterized in that, The composite nanoparticles include optional modified or altered materials selected from at least one of organic materials, inorganic materials, and organic-inorganic hybrid materials.

5. The application according to claim 1, characterized in that, The composite nanoparticles have a particle size of 50-500 nm.

6. The application according to claim 1, characterized in that, The preparation of the composite nanoparticles includes the following steps: (1) Preparation of a core containing a cobalt spinel-type oxide phase; (2) A precursor solution containing a bismuth source is used to form a shell covering the surface of the core; Preferably, a shell covering the core is formed on the surface of the core by methods including spin coating, dip-coating, sol-gel, or hydrothermal / solvothermal methods.

7. The application according to claim 6, characterized in that, The composite nanoparticles are further treated with an external magnetic field after step (2).

8. The application according to claim 1, characterized in that, The dosage forms of the drug include injections, solutions, transdermal patches, implants, nasal preparations, or sublingual tablets.

9. The application according to claim 1, characterized in that, The drug is in the form of an injection, preferably an injection suspension or a lyophilized powder for injection.

10. The application of composite nanoparticles and magnetic field therapy devices in the preparation of products for combined treatment of Alzheimer's disease, characterized in that, The composite nanoparticles are the composite nanoparticles used in any one of claims 1-9.

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