MXene (at) Au photo-thermal nano motor as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of nano motors, and particularly relates to an MXene (at) Au photo-thermal nano motor and a preparation method and application thereof. The MXene (at) Au composite nano motor provided by the invention comprises a modified single-layer MXene nanosheet and an active component loaded on the surface of the modified single-layer MXene nanosheet, the active component is a gold nano-cluster coated with bovine serum albumin; the modified single-layer MXene nanosheet is obtained by modifying with a cationic surface active agent; the loading is realized through an electrostatic adsorption effect. The MXene (at) Au nano motor provided by the invention generates an asymmetric thermal gradient under illumination to drive the nano motor to realize self-propelling movement in a solution, so that the diffusion efficiency and the A beta targeted enrichment capacity in a complex biological medium can be remarkably enhanced, and further efficient recognition and photo-thermal degradation of A beta protein aggregates are realized.

Description

Technical Field

[0001] This invention belongs to the field of nanomotor technology, specifically relating to an MXene@Au photothermal nanomotor, its preparation method, and its application. Background Technology

[0002] Alzheimer's disease (AD) is a progressive neurodegenerative disease, one of its typical pathological features being the abnormal aggregation of β-amyloid-β (Aβ) in the brain, forming oligomers and fibrillary plaques, which in turn lead to neuronal damage, synaptic dysfunction, and cognitive decline. Currently, there are no effective clinical methods to reverse or eliminate existing Aβ aggregates. Traditional drug treatments mostly focus on inhibiting Aβ production or delaying its deposition, but their efficacy is limited and they are difficult to penetrate the blood-brain barrier (BBB). Therefore, developing novel therapeutic strategies that can target and efficiently degrade Aβ aggregates has become an important direction in AD intervention research.

[0003] In recent years, nanotechnology has provided new insights into Aβ targeted clearance. Among these, nanomaterials with photothermal conversion capabilities can locally generate heat under near-infrared (NIR) irradiation, inducing conformational changes and even degradation of Aβ, while exhibiting good tissue penetration and spatiotemporal controllability. Gold nanoclusters (AuNcs) are widely used in bioimaging and therapy due to their excellent biocompatibility, strong fluorescence properties, and mild photothermal effect; while two-dimensional transition metal carbon / nitrides (MXenes) exhibit high specific surface area, excellent near-infrared absorption, and good drug loading capacity. However, single-component nanomaterials often struggle to simultaneously meet the multiple requirements of efficient photothermal conversion, Aβ targeted recognition, and biosafety. For example, the paper "Liu, Dongni, et al. "Using near-infrared enhanced thermozyme and scFv dual-conjugated Au nanorods for detection and targeted photothermal treatment of Alzheimer's disease." Theranostics 9.8 (2019): 2268" reports a multifunctional gold nanorod platform that achieves targeted recognition, inhibition, and near-infrared photothermal degradation of Aβ aggregates by covalently coupling thermostable amylase (APH) and anti-Aβ single-chain antibody (scFv) on the surface of GNRs. Its shortcomings are as follows: (1) The photothermal conversion efficiency of GNRs is limited, requiring a high laser power (>1.5 W / cm). 2(1) It can only achieve effective degradation, which easily causes non-specific thermal damage; (2) It lacks autonomous movement ability and spreads slowly in viscous cerebrospinal fluid or interstitial spaces, making it difficult to efficiently contact and act on deep Aβ deposition areas; (3) Its function is highly dependent on exogenous biomacromolecules. GNRs themselves only have photothermal capabilities and must be additionally coupled with APH enzymes and scFv antibodies to achieve Aβ inhibition and targeting. This not only greatly increases the complexity and cost of preparation, but also makes exogenous proteins easily degraded by intracellular proteases, cleared by immunity or inactivated, resulting in functional instability; In addition, "Liu, Shasha, Jinrong Yang, and Jinwu Yan. Chemiexcitation-triggered photosensitizer activation for photooxidation of Aβ1-42 aggregates." ACS Applied Materials & Interfaces 16.32 (2024): 41843-41854》constructed a chemically activated nanoplatform (BD-SE-QM / NPS), which activated the photosensitizer BD-Se-QM through the chemical energy generated by the reaction of H2O2 with oxalate ester to achieve the oxidative degradation of Aβ aggregates. The drawbacks are: (1) it depends on exogenous chemical fuels (such as H2O2), while the concentration of H2O2 in the physiological environment is extremely low and unstable, and the response is uncontrollable; (2) although BD-Se-QM has Aβ affinity, it has no autonomous movement ability and still depends on passive diffusion contact, which limits its efficiency; (3) it only oxidatively degrades Aβ aggregates by generating ROS, but AD brain tissue itself is in a state of chronic oxidative stress, and the additional introduction of ROS may aggravate neuronal damage, which poses a safety risk.

[0004] Furthermore, constructing nanomaterials into autonomous "nanomotors" can enhance their penetration efficiency and targeted accumulation capacity in complex biological media by improving diffusion effects, thereby significantly increasing their effectiveness against Aβ aggregates. However, existing nanomotors mostly rely on chemical fuels for propulsion, exhibiting poor stability and high biotoxicity in physiological environments, which limits their clinical translation potential. Summary of the Invention

[0005] In view of this, the present invention provides an MXene@Au photothermal nanomotor, its preparation method and application. The MXene@Au composite nanomotor provided by the present invention can achieve effective self-propulsion under near-infrared light drive, and can achieve efficient recognition and photothermal degradation of Aβ protein aggregates.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an MXene@Au composite nanomotor, comprising modified monolayer MXene nanosheets and an active component loaded on the surface of the modified monolayer MXene nanosheets; the active component is gold nanoclusters coated with bovine serum albumin; the modified monolayer MXene nanosheets are obtained by modification with cationic surfactants; the loading is achieved through electrostatic adsorption.

[0007] Preferably, the particle size of the MXene@Au composite nanomotor is 200~800 nm.

[0008] This invention also provides a method for preparing the MXene@Au composite nanomotor described in the above technical solution, comprising the following steps: The MXene aqueous dispersion was ultrasonically exfoliated to obtain a monolayer MXene nanosheet aqueous dispersion. A first mixing of a monolayer MXene nanosheet aqueous dispersion and a cationic surfactant solution was performed to adsorb the cationic surfactant, resulting in a modified monolayer MXene nanosheet dispersion. The modified monolayer MXene nanosheet dispersion and the bovine serum albumin-coated gold nanocluster solution were mixed for a second time and coupled to obtain an MXene@Au composite nanomotor.

[0009] Preferably, the concentration of the MXene aqueous dispersion is 0.2~2 mg / mL.

[0010] Preferably, the ultrasonic ablation is performed under ice bath conditions; the frequency of the ultrasonic ablation is 30~50kHz, and the ultrasonic ablation time is 20~60 min.

[0011] Preferably, the concentration of the cationic surfactant solution is 2~10 mM; the volume ratio of the monolayer MXene nanosheet aqueous dispersion to the cationic surfactant solution is 100:10~100:5.

[0012] Preferably, the concentration of the BSA-AuNcs solution is 0.2~1 mg / mL.

[0013] Preferably, the coupling reaction is carried out under stirring conditions; the coupling reaction time is 18-24 hours.

[0014] This invention also provides the application of the MXene@Au composite nanomotors described in the above technical solutions or the MXene@Au composite nanomotors prepared by the above preparation methods in the preparation of photothermal degradation Aβ aggregate products.

[0015] This invention provides an MXene@Au composite nanomotor, comprising modified monolayer MXene nanosheets and an active component loaded on the surface of the modified monolayer MXene nanosheets; the active component is bovine serum albumin-coated gold nanoclusters; the modified monolayer MXene nanosheets are obtained by modifying monolayer MXene nanosheets with a cationic surfactant; the loading is achieved through electrostatic adsorption. This system uses monolayer MXene nanosheets as a substrate, and improves its dispersion stability and imparts a positive charge by surface modification with the cationic surfactant CTAB, thereby loading bovine serum albumin-coated gold nanoclusters (BSA-AuNcs) through electrostatic adsorption. BSA not only acts as a stabilizer to prevent AuNcs aggregation, but also possesses a weak Aβ affinity, which can synergistically enhance the composite system's targeted recognition of Aβ. This invention achieves non-uniform loading of gold nanoclusters on the MXene surface by precisely controlling material parameters, thereby constructing a photothermal nanomotor with structural asymmetry. This asymmetric configuration is key to driving self-propulsion: under near-infrared laser irradiation, MXene and locally loaded gold nanoclusters synergistically generate an asymmetric photothermal field, forming a thermophoretic effect driven by a thermal gradient, thereby initiating autonomous motion. Therefore, the MXene@Au composite nanomotor of this invention forms an effective thermal / mass / dielectric property gradient, thus activating the active motion function of the nanomotor and providing a kinetic basis for efficient targeting of Aβ aggregates.

[0016] Compared to existing technologies, it has the following advantages: (1) The MXene@Au composite nanomotor has a similar particle size to MXene and exhibits good dispersion stability.

[0017] (2) MXene has excellent photothermal properties and photothermal stability. MXene@Au nanomotors generate an asymmetric thermal gradient under light, which drives the nanomotors to achieve self-propulsion in the solution, which can significantly enhance the diffusion efficiency and Aβ targeting enrichment ability in complex biological media.

[0018] (3) MXene@Au composite nanomotors have high photothermal conversion efficiency and can efficiently degrade Aβ aggregates. The specific reason is that MXene has a unique layered structure, multi-element composition (carbon / nitrogen / metal) and electronic structure characteristics, which enable it to efficiently absorb light across the entire wavelength range (ultraviolet-near-infrared-mid-infrared) and convert photon energy into heat energy rapidly through non-radiative relaxation. At the same time, the photon trapping effect of the layered structure and the free electron relaxation of the metallic phase further amplify the photothermal conversion efficiency. The photothermal conversion efficiency of most MXenes can reach 60%~90%.

[0019] (4) The mechanism of action is multi-synergistic. The MXene@Au nanomotor has both the physical inhibition effect of gold nanoclusters on Aβ aggregation and the photothermal induced conformational melting effect.

[0020] (5) Good biosafety; constructed with biocompatible materials (BSA, MXene) and driven by non-invasive near-infrared light with strong tissue penetration, avoiding the toxicity of chemical fuels. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0022] Figure 1 TEM image of BSA-AuNcs; Figure 2 TEM images and elemental analysis of MXene@Au; Figure 3 The ultraviolet absorption spectra of different components are shown. Figure 4 Fluorescence spectra of different components; Figure 5 Zeta potential diagrams for different components; Figure 6 The graph shows the cell viability after adding different concentrations of MXene@Au nanomotors as determined by the CCK-8 assay. Figure 7 The photothermal conversion efficiency of MXene@Au is shown in the figure. Figure 8 The mean square displacement (MSD) plot of the MXene@Au nanomotor; Figure 9 The graph shows the degradation effect of MXene@Au nanomotors on Aβ aggregates under different concentration conditions; Figure 10 The fluorescence spectra of the supernatant and redisperse of Comparative Example 1 are shown. Detailed Implementation

[0023] This invention provides an MXene@Au composite nanomotor (hereinafter referred to as MXene@Au nanomotor), comprising modified monolayer MXene nanosheets and an active component loaded on the surface of the modified monolayer MXene nanosheets; the active component is gold nanoclusters coated with bovine serum albumin; the modified monolayer MXene nanosheets are obtained by modification with cationic surfactants; the loading is achieved through electrostatic adsorption.

[0024] In one embodiment of the present invention, the cationic surfactant may be hexadecyltrimethylammonium bromide (CTAB).

[0025] As one embodiment of the present invention, the particle size of the MXene@Au composite nanomotor can be 200~800nm, specifically 451nm.

[0026] This invention also provides a method for preparing the MXene@Au composite nanomotor described in the above technical solution, comprising the following steps: The MXene aqueous dispersion was ultrasonically exfoliated to obtain a monolayer MXene nanosheet aqueous dispersion. A first mixing of a monolayer MXene nanosheet aqueous dispersion and a cationic surfactant solution was performed to adsorb the cationic surfactant, resulting in a modified monolayer MXene nanosheet dispersion. The modified monolayer MXene nanosheet dispersion and the bovine serum albumin-coated gold nanocluster solution were mixed for a second time and coupled to obtain an MXene@Au composite nanomotor.

[0027] This invention involves ultrasonically exfoliating an MXene aqueous dispersion to obtain a monolayer MXene nanosheet aqueous dispersion.

[0028] In one embodiment of the present invention, the concentration of the MXene aqueous dispersion can be 0.2~2 mg / mL, specifically 0.5 mg / mL; the ultrasonic exfoliation can be performed under ice bath conditions; the frequency of the ultrasonic exfoliation can be 30~50 kHz, specifically 40 kHz; and the ultrasonic exfoliation time can be 20~60 min, specifically 30 min.

[0029] After obtaining the aqueous dispersion of monolayer MXene nanosheets, the present invention first mixes the aqueous dispersion of monolayer MXene nanosheets with a cationic surfactant solution to perform cationic surfactant adsorption, thereby obtaining a modified monolayer MXene nanosheet dispersion.

[0030] In one embodiment of the present invention, the cationic surfactant may be hexadecyltrimethylammonium bromide (CTAB); the concentration of the cationic surfactant solution may be 2-10 mM, specifically 5 mM; the volume ratio of the monolayer MXene nanosheet aqueous dispersion to the CTAB solution may be 100:10-100:5, specifically 100:8.

[0031] In one embodiment of the present invention, the cationic surfactant is adsorbed under stirring conditions; the adsorption time of the cationic surfactant can be 1.5~3.6 h, specifically 2 h.

[0032] After obtaining the modified monolayer MXene nanosheets, the present invention further mixes the modified monolayer MXene nanosheet dispersion with a solution of gold nanoclusters coated with bovine serum albumin (denoted as BSA-AuNcs) and performs a coupling reaction to obtain an MXene@Au composite nanomotor.

[0033] In one embodiment of the present invention, the concentration of the BSA-AuNcs solution can be 0.2~1 mg / mL, specifically 0.4 mg / mL; the volume ratio of the modified monolayer MXene nanosheet dispersion to the BSA-AuNcs solution can be 5.4:1~5.4:2.5, specifically 5.4:2.

[0034] In one embodiment of the present invention, the coupling reaction can be carried out under stirring conditions; the coupling reaction time can be 18-24 h, specifically 18 h.

[0035] This invention also provides the application of the MXene@Au composite nanomotors described above in the preparation of photothermally degradable Aβ aggregate products.

[0036] The application described in this invention has the following advantages: (1) During the synthesis or storage of raw MXene, due to the interlayer van der Waals forces and the hydrogen bonding between surface functional groups, it is very easy to re-stack, forming few-layer or multi-layer aggregates, which leads to a decrease in specific surface area and surface active sites, which is not conducive to subsequent functionalization modification. The key to constructing high-performance light-driven nanomotors lies in obtaining highly dispersed monolayer or few-layer MXene. On the one hand, its particle size needs to be precisely controlled, and on the other hand, the surface needs to be effectively modified by CTAB to enhance the loading capacity of AuNcs. Therefore, it is usually necessary to use ultrasonic exfoliation to dissociate it into a monolayer structure, thereby obtaining the high-performance light-driven nanomotor of the present invention.

[0037] (2) By utilizing the excellent near-infrared photothermal conversion efficiency of MXene and the mild photothermal properties of AuNcs, a two-component synergistic photothermal system is constructed. Under low-power NIR irradiation, a local thermal effect can be generated, which can effectively destroy the β-sheet structure of Aβ and promote its degradation into non-toxic monomers. (3) By rationally designing the interface interaction, the composite structure generates an asymmetric thermal gradient under light, driving the nanomotor to achieve self-propulsion in the solution, which significantly improves its diffusion rate and Aβ contact efficiency in complex media such as simulated cerebrospinal fluid. (4) The entire system contains no chemical fuels and relies solely on external NIR light-driven propulsion, exhibiting excellent biocompatibility and precise spatiotemporal control capabilities. Data from the examples show that the MXene@Au nanomotor can effectively degrade the formed Aβ fibers under 808 nm laser irradiation and significantly reduce their cytotoxicity. Compared to single MXene or AuNcs, the composite system exhibits superior photothermal stability, Aβ binding capacity, and degradation efficiency. Therefore, this invention not only provides a potential non-invasive treatment tool for Alzheimer's disease but also opens up new pathways for the design and application of multifunctional light-driven nanomotors.

[0038] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0039] The raw materials used in this embodiment are sourced as follows:

[0040] Example 1 (1) Preparation of AuNcs Five mL of a 10 mM tetrachloroauric acid (HAuCl4) solution was added to five mL of a 50 mg / mL BSA solution, and the mixture was stirred vigorously at 37°C for 2 min. Then, 0.5 mL of a 1 mol / L NaOH solution was added to the mixture to adjust the pH to 12, and the mixture was incubated at 37°C for 12 h. After the reaction was complete, the product was purified by ultrafiltration using an ultrafiltration tube with a molecular weight cutoff (MWCO) of 100 kDa to remove some unreacted impurity molecules and ions. The purified sample was freeze-dried for 10 h to obtain a solid powder product (i.e., BSA-AuNcs).

[0041] Figure 1 TEM images of BSA-AuNcs, by Figure 1 It can be seen that the particle size of BSA-AuNcs is about 2 nm.

[0042] (2) Fabrication of MXene@Au nanomotors A 10 mg / mL MXene dispersion was washed twice with 1 mol / L NaOH solution at a volume ratio of 4:1 (MXene dispersion to NaOH solution) to remove impurities, resulting in MXene precipitate. After washing, the MXene precipitate was redispersed in deionized water to prepare a 0.5 mg / mL MXene aqueous dispersion. Subsequently, the dispersion was sonicated at a frequency of 40 kHz for 30 min under ice bath conditions to obtain monolayer MXene nanosheets through ultrasonic mechanical exfoliation. 5 mL of the above monolayer MXene dispersion was added to 400 μL of a 5 mM CTAB solution, and the mixture was reacted with gentle stirring (300 rpm) for 2 h to allow CTAB molecules to adsorb onto the surface of the MXene nanosheets. Subsequently, 2 mL of a 0.4 mg / mL aqueous solution of BSA-coated gold nanoclusters (denoted as BSA-AuNcs) was added, and the reaction was continued at 800 rpm for 18 h to couple MXene with BSA-AuNcs to form an MXene / CTAB / BSA-AuNcs composite system. After the reaction, the resulting composite system was transferred to a dialysis bag (molecular weight cutoff of 100 kDa) and dialyzed in deionized water for 24 h to remove unreacted impurity molecules and ions. After dialysis, the purified solution was freeze-dried for 10 h to obtain the MXene@Au composite nanomotor (denoted as MXene@Au).

[0043] Figure 2 For high-resolution transmission electron microscopy (HRTEM) bright-field images of MXene@Au combined with corresponding elemental distribution maps (EDS mapping), from Figure 2 It can be seen that the Au element signal is uniformly distributed on the surface of MXene nanosheets, and its spatial distribution overlaps significantly with that of MXene characteristic elements such as Ti and O, but the boundaries are clear, indicating that AuNcs has been successfully loaded onto the MXene surface.

[0044] Figure 3 The ultraviolet absorption spectra of different components are shown below. Figure 3 It can be seen that MXene (the host material) has good absorption in the near-infrared region.

[0045] Figure 4 The fluorescence spectra of different components are shown below. Figure 4It can be seen that AuNcs exhibits characteristic red fluorescence emission under 365 nm UV excitation, with its maximum emission peak located at approximately 704 nm; while MXene shows no obvious fluorescence signal under the same conditions. In the fluorescence spectrum of the prepared MXene@Au composite material, the characteristic emission peak located at approximately 700 nm can still be clearly observed, and its peak shape is highly consistent with that of free AuNcs. The effective preservation of its fluorescence properties indicates that AuNcs was successfully loaded onto the MXene surface.

[0046] Figure 5 Zeta potential diagrams for different components, from Figure 5 It can be seen that the Zeta potentials of both MXene and AuNcs are negative, but the surface potential of MXene changes after being modified by CTAB (from negative to positive). Therefore, based on the principle of electrostatic adsorption, AuNcs was successfully loaded onto the surface of MXene.

[0047] To systematically evaluate the dispersibility and structural stability of MXene@Au nanomotors, dynamic light scattering (DLS) was used to determine the particle size distribution of MXene before and after loading AuNcs. The results showed that the original MXene had a wider particle size distribution curve and a smaller main peak, reflecting a certain degree of lamellar stacking or aggregation in the aqueous phase, leading to non-uniform particle size. However, after successful loading of BSA-AuNcs (i.e., the MXene@Au composite system), the particle size distribution curve shifted significantly to the right, and the hydrodynamic diameter corresponding to the main peak increased significantly, confirming that AuNcs was effectively anchored on the MXene surface, forming a composite structure. Importantly, the modified particle size distribution still exhibited a single, symmetrical main peak with a narrow half-width at half-maximum (PDI), indicating that the composite process did not induce significant secondary aggregation or structural disorder. The resulting MXene@Au nanomotors possessed good colloidal dispersibility, size uniformity, and structural stability.

[0048] To systematically evaluate the biocompatibility of MXene@Au nanomotors, the cytotoxicity of MXene@Au nanomotors to HT22 nerve cells at different concentrations (0–200 μg / mL) was detected using the CCK-8 assay. The experimental results are shown below. Figure 6 The results showed that within this concentration range, the cell survival rate of each group remained above 90%, and no obvious dose-dependent toxicity trend was observed, indicating that the MXene@Au nanomotors had no significant adverse effects on cell proliferation and activity. This excellent biocompatibility not only confirms the good biosafety of the material itself, but also lays a solid foundation for subsequent in vitro Aβ degradation experiments, cellular functional verification, and potential in vivo applications.

[0049] To systematically evaluate the photothermal performance of MXene@Au nanomotors, their photothermal conversion efficiency and self-propulsion capability under 808 nm laser irradiation were measured. Results are shown below. Figure 8 The results showed that within 8 minutes of continuous irradiation with an 808 nm laser, the nanomotor exhibited a significant and rapid temperature rise response. It converted light energy into heat energy, causing a local temperature increase, and then depolymerized and degraded the Aβ aggregates by breaking the weak intermolecular forces and inducing conformational rearrangement. Especially under high concentration (500 μg / mL) conditions, the system temperature rise could reach 28 °C. Based on thermodynamic model calculations, its photothermal conversion efficiency was as high as 52.9% (…). Figure 7 This fully demonstrates its application potential as a highly efficient photothermal agent. Furthermore, it was demonstrated at different laser power densities (0, 0.4, 0.8, and 1.2 W / cm²). 2 Tracking and analyzing its motion behavior revealed that its mean square displacement (MSD) significantly increased with increasing concentration, and was significantly higher under illumination than the unilluminated control group, exhibiting good concentration dependence and light-controlled response. These results demonstrate that the MXene@Au nanomotor not only possesses excellent photothermal conversion capabilities but also achieves effective self-propulsion under near-infrared light, laying a functional foundation for its active targeting and photothermal degradation of Aβ aggregates in complex biological environments. Figure 8 ).

[0050] Quantitative analysis was performed using thioflavin S (ThS) fluorescence staining. The specific experimental procedure was as follows: First, 100 μL of Aβ aggregate solution (final concentration 40 μM) was co-incubated with different concentrations (0, 50, 100, and 200 μg / mL) of MXene@Au nanomotors; subsequently, the mixture was incubated at a power density of 1.2 W / cm². 2 The samples were treated with 808 nm laser irradiation for 10 min to activate its photothermal effect. After irradiation, 10 μL of ThS stock solution (final concentration 5 μM) was immediately added, mixed, and stained in the dark for 30 min. ThS specifically binds to Aβ fiber structures and generates a strong fluorescence signal, with the fluorescence intensity positively correlated with the Aβ aggregate content. Finally, the fluorescence intensity of each group of samples was measured using a microplate reader at an excitation wavelength of 440 nm and an emission wavelength of 521 nm. The Aβ aggregate group without nanomotors and without light irradiation was used as a control. The degradation efficiency of Aβ aggregates by different concentrations of MXene@Au nanomotors was calculated by the relative decrease in fluorescence intensity. Figure 9 The graph shows the degradation effect of MXene@Au nanomotors on Aβ aggregates under different concentration conditions. Figure 9It can be seen that the Aβ-related fluorescence intensity decreases significantly with the increase of nanomotor concentration, indicating that MXene@Au degrades Aβ aggregates through photothermal temperature rise under 808 nm laser irradiation, and the depolymerization efficiency is up to nearly 70%, showing obvious concentration dependence. This indicates that MXene@Au nanomotors can efficiently depolymerize Aβ aggregates under near-infrared light control conditions and have good application potential in AD treatment.

[0051] Comparative Example 1 The difference from Example 1 is that CTAB was not added; BSA-AuNcs solution was added to the MXene dispersion and loaded using two methods: stirring for 18 hours and sonication for 5 hours. The mixtures obtained by both methods were centrifuged and washed three times, then redispersed in deionized water. Fluorescence spectra of the washed dispersion and the supernatant after the first centrifugation were measured. It was found that there was no obvious AuNcs-specific fluorescence emission wavelength in the dispersion, indicating that without CTAB modification, the AuNcs loading effect was poor. This is because the MXene surface is negatively charged (ζ≈-35 mV), and BSA-AuNcs is also weakly negatively charged (ζ≈-22 mV), resulting in electrostatic repulsion and extremely low coupling efficiency, leading to poor loading (see results in [link to example]). Figure 10 ).

[0052] Comparative Example 2 (2) Replace “400 μL of 5 mM CTAB solution” in Example 1 with 1 mL of 5 mM CTAB solution.

[0053] The results showed that excessive CTAB caused the MXene dispersion to agglomerate, which was detrimental to the subsequent loading of AuNcs and the construction of nanomotors.

[0054] Comparative Example 3 Replace “continue reaction for 18 hours” in Example 1 with “continue reaction for 2 hours”.

[0055] The results showed that BSA-AuNcs were only partially adsorbed on the MXene surface, with a large amount remaining free in the solution.

[0056] Comparative Example 4 Replace "continue reaction for 18 hours" in Example 1 with "continue reaction for 36 hours". The result was that prolonged and vigorous stirring caused precipitation during the preparation of the nanomotor, resulting in a significant decrease in stability.

[0057] This invention proposes a near-infrared light-driven, self-propelled MXene@Au nanomotor, which features a simple fabrication process, stable structure, excellent biocompatibility, and multifunctional integration. Utilizing the synergistic photothermal effect of MXene and AuNcs, this nanomotor can generate a locally controllable temperature rise (approximately 50-55°C) under near-infrared light (808 nm) irradiation. This thermal energy directly disrupts the β-sheet hydrogen bond network of Aβ, achieving efficient physical melting-type degradation. This provides a safe, precise, tunable, and clinically promising new intelligent nanotherapy strategy for Alzheimer's disease.

[0058] The above results indicate that AuNcs were successfully loaded onto the MXene surface via electrostatic adsorption, constructing a structurally stable and biosafety-friendly light-driven MXene@Au nanomotor. This nanomotor effectively degrades Aβ aggregates by utilizing photothermal temperature rise, overcoming the shortcomings of traditional nanomedicines that rely on passive transport and have low targeting efficiency, and providing a new strategy for AD treatment.

[0059] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An MXene@Au composite nanomotor, characterized in that, The invention comprises modified monolayer MXene nanosheets and an active component loaded on the surface of the modified monolayer MXene nanosheets; the active component is gold nanoclusters coated with bovine serum albumin; the modified monolayer MXene nanosheets are obtained by modification with a cationic surfactant. The loading is achieved through electrostatic adsorption; the cationic surfactant is hexadecyltrimethylammonium bromide.

2. The MXene@Au composite nanomotor as described in claim 1, characterized in that, The particle size of the MXene@Au composite nanomotor is 200~800 nm.

3. The method for preparing the MXene@Au composite nanomotor according to any one of claims 1 to 2, characterized in that, Includes the following steps: The MXene aqueous dispersion was ultrasonically exfoliated to obtain a monolayer MXene nanosheet aqueous dispersion. A first mixing of a monolayer MXene nanosheet aqueous dispersion and a cationic surfactant solution was performed to adsorb the cationic surfactant, resulting in a modified monolayer MXene nanosheet dispersion. The modified monolayer MXene nanosheet dispersion and the bovine serum albumin-coated gold nanocluster solution were mixed for a second time and coupled to obtain an MXene@Au composite nanomotor.

4. The preparation method according to claim 3, characterized in that, The concentration of the MXene aqueous dispersion is 0.2~2 mg / mL.

5. The preparation method according to claim 3, characterized in that, The ultrasonic ablation is performed under ice bath conditions; the frequency of the ultrasonic ablation is 30~50kHz, and the ultrasonic ablation time is 20~60 min.

6. The preparation method according to claim 3, characterized in that, The concentration of the cationic surfactant solution is 2~10 mM.

7. The preparation method according to claim 3, characterized in that, The volume ratio of the monolayer MXene nanosheet aqueous dispersion to the cationic surfactant solution is 100:10 to 100:

5.

8. The preparation method according to claim 3, characterized in that, The concentration of the bovine serum albumin-coated gold nanocluster solution is 0.2~1 mg / mL.

9. The preparation method according to claim 3, characterized in that, The coupling reaction is carried out under stirring conditions; the coupling reaction time is 18-24 hours.

10. The application of the MXene@Au composite nanomotor according to any one of claims 1 to 2 or the MXene@Au composite nanomotor prepared by the preparation method according to any one of claims 3 to 9 in the preparation of photothermal degradable Aβ aggregate products.

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