Bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles as well as preparation method and application of bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles

Abstract

The invention relates to bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles as well as a preparation method and application of the bionic ferroptosis nanoparticles. The biomimetic ferroptosis nano-particles are obtained by loading the superparamagnetic iron oxide nano-particles packaged by the biomimetic platelet membrane, Erastin and lactate oxidase together, and are used for guiding magnetic resonance imaging and inducing tumor cell ferroptosis. According to the method, ferroptosis is induced through Erastin, lactic acid is removed through lactate oxidase, and ferroptosis is enhanced. In addition, lactic acid is oxidized to generate hydrogen peroxide, the hydrogen peroxide is converted into cytotoxic hydroxyl radicals, and cell death is further accelerated. When the PM-ESLNP is combined with an alphaPD-L1 immunotherapy, the PM-ESLNP obviously inhibits tumor growth and metastasis in a liver cancer mouse model, and the result exceeds that of a single immunotherapy. In addition, the superparamagnetic nanoparticles in the PM-coated ESLNP can be used for carrying out real-time MRI (Magnetic Resonance Imaging) monitoring on the treatment effect. According to the invention, a groundbreaking MRI guiding method is introduced, so that ferroptosis of tumors can be enhanced and tumor immunotherapy can be synergistically improved.

Description

Technical Field

[0001] The present invention relates to the field of biomedical technology, and in particular to bionic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles, and a preparation method and application thereof. Background Art

[0002] Liver cancer poses a major challenge to global health, with an increasing incidence worldwide. Hepatocellular carcinoma (HCC) is the main type of liver cancer, accounting for approximately 90% of all cases. Due to its insidious and rapid progression, more than half of HCC patients are diagnosed at an advanced stage, with radiotherapy, chemoembolization, and systemic drug therapy as the main treatment options. Unfortunately, these approaches often produce unsatisfactory results due to the intrinsic or acquired resistance to apoptosis of cancer cells. Therefore, there is an urgent need for drugs that can trigger alternative cell death pathways to circumvent the limitations of traditional drugs targeting apoptosis.

[0003] Ferroptosis is a non-apoptotic form of programmed cell death discovered in the past decade that is morphologically, genetically, and biochemically distinct from other established types of regulated cell death. This iron-dependent cell death process is associated with the intracellular Fe 2+ / Fe 3+ These iron ions are closely related to hydrogen peroxide (H 2 O 2 ) together with the Fenton reaction, accelerating the accumulation of reactive oxygen species (ROS), leading to lipid peroxidation (LPO) in the cell membrane and ultimately inducing ferroptosis. Erastin is a universal ferroptosis inducer that blocks the cystine / glutamate antiporter system Xc - to inhibit intracellular glutathione (GSH) biosynthesis. However, the tumor microenvironment (TME) can significantly reduce the cytotoxic effects of ferroptosis inducers. Recent studies have shown that cells with elevated extracellular lactate levels, a byproduct of glycolysis, generally have greater resistance to ferroptosis damage induced by common ferroptosis inducers. Therefore, there is an urgent need to develop strategies that can reverse the immunosuppressive properties of the TME while triggering effective anti-tumor immune responses. These efforts are critical to improving the efficacy of ferroptosis therapy (FT) and immunotherapy in cancer treatment.

[0004] In addition, superparamagnetic iron oxide (SPIO) is the main T2 contrast agent in magnetic resonance imaging (MRI). It causes protons in its vicinity to undergo spin-spin relaxation, showing negative contrast on T2-weighted MRI images. The development of activatable MRI contrast agents that can recognize and adapt to the TME to change their contrast will further enhance the distinction between normal and diseased tissues. Although these nanomaterials have demonstrated the potential to improve the effectiveness of ferroptosis in cancer treatment, their clinical application remains limited due to challenges in immune evasion. Due to their inherent self-recognition properties, the cell membranes of entities such as red blood cells, platelets, and macrophages have been used to disguise nanoparticles, allowing them to evade immune clearance. These cell membrane-camouflaged nanoparticles have been shown to be effective in immunomodulation. Nanoparticles disguised with platelet membranes (PMs) have been widely used in targeted cancer therapy due to the inherent advantages of platelets, including their rapid response to vascular injury and their ability to recognize and interact with circulating tumor cells. Therefore, PM-modified nanoparticles that combine immune evasion and tumor targeting capabilities can optimize the delivery of ferroptosis-inducing agents to tumors, thereby fully realizing their potential to treat tumor metastasis. Summary of the invention

[0005] To solve the above technical problems, the present invention provides a biomimetic ferroptosis nanoparticle loaded with superparamagnetic iron oxide nanoparticles, and a preparation method and application thereof. The present invention introduces an innovative MRI-guided method, using PM-encapsulated SPIO co-loaded with Erastin and lactate oxidase (LOX) (PM@ESLNPs) to induce tumor cell ferroptosis. These nanoparticles are carefully designed to adhere to damaged vascular areas through interactions with the surface of the particles, thereby specifically targeting the tumor site and accumulating at the tumor site. This strategy not only triggers ferroptosis through Erastin, but also promotes the removal of lactate through the action of LOX, thereby amplifying the ferroptosis process. In addition, lactate consumption produces a large amount of H 2 O 2 , subsequently producing cytotoxic ·OH, exacerbating cell destruction. When used together with αPD-L1, PM@ESLNP significantly inhibited tumor growth and metastasis in a mouse model of liver cancer, significantly outperforming immunotherapy alone. SPIO in PM@ESLNP also allowed real-time MRI monitoring of treatment progress, thereby enhancing the monitoring of treatment effects. Overall, the present study proposes a powerful MRI-guided method that can not only enhance cancer ferroptosis, but also synergistically enhance the effectiveness of immunotherapy.

[0006] The present invention is achieved through the following technical solutions:

[0007] The first purpose of the present invention is to provide a bionic ferroptosis nanoparticle loaded with superparamagnetic iron oxide nanoparticles, comprising an outer shell and an inner core coated in the outer shell; the outer shell is a platelet membrane; the inner core comprises superparamagnetic iron oxide nanoparticles, a ferroptosis inducer and lactate oxidase; the content of the ferroptosis inducer in the bionic ferroptosis nanoparticles is 3.12% to 3.36%, the content of lactate oxidase is 0.167% to 0.325%, and the content of the superparamagnetic iron oxide nanoparticles is 2.42% to 3.57%.

[0008] In one embodiment of the present invention, the ferroptosis inducing agent is selected from Erastin.

[0009] In one embodiment of the present invention, the particle size of the bionic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles is 176.31 nm to 191.89 nm.

[0010] In one embodiment of the present invention, the superparamagnetic iron oxide nanoparticles are prepared by the following method:

[0011] Under nitrogen, Fe(acac) 3 , 1,2-hexadecanediol, oleic acid and oleylamine are dissolved in diphenyl ether and refluxed, and the mixture is heated for reaction to obtain the superparamagnetic iron oxide nanoparticles.

[0012] The second object of the present invention is to provide a method for preparing the bionic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles, characterized in that it comprises the following steps:

[0013] (1) mixing an aqueous solution of lactate oxidase with an organic solvent containing PLGA, a ferroptosis inducer and superparamagnetic iron oxide nanoparticles, and obtaining an emulsion after ultrasonic treatment; stirring the obtained emulsion with a polyvinyl alcohol solution at room temperature to obtain ESLNPs;

[0014] (2) extracting mouse platelets by gradient centrifugation, and subjecting the extracted platelets to repeated freezing and thawing and ultrasonic treatment to obtain platelet membrane fragments;

[0015] (3) The buffer solution containing the ESLNPs prepared in step (1) is mixed with the platelet membrane fragments obtained in step (2), and after ultrasonication and extrusion, the bionic ferroptosis nanoparticles PM@ESLNP loaded with superparamagnetic iron oxide nanoparticles are obtained.

[0016] In one embodiment of the present invention, in step (3), the concentration of ESLNPs in the ESLNPs solution is 1.0 mg / mL to 3.5 mg / mL.

[0017] The third object of the present invention is to provide an immunogenic cell death inducer, comprising the bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles.

[0018] The fourth objective of the present invention is to provide the use of the bionic ferroptotic nanoparticles loaded with superparamagnetic iron oxide nanoparticles in the preparation of anti-tumor drugs.

[0019] In one embodiment of the present invention, the drug also includes αPD-L1.

[0020] The fifth object of the present invention is to provide the use of the bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles in the preparation of tumor nuclear magnetic resonance contrast agents.

[0021] The sixth objective of the present invention is to provide the use of the bionic ferroptosis nanoparticles loaded with superparamagnetic iron oxide nanoparticles in the preparation of anti-tumor metastasis drugs; the drug also includes αPD-L1.

[0022] The above technical solution of the present invention has the following advantages compared with the prior art:

[0023] The present invention provides a bionic ferroptosis nanoparticle loaded with superparamagnetic iron oxide nanoparticles and a preparation method and application thereof. The bionic ferroptosis nanoparticles of the present invention can induce ferroptosis and are used for the treatment of HCC. Due to the high concentration of lactic acid in tumor tissue, a large amount of H is accumulated during the LOX catalysis process. 2 O 2 , increasing intracellular ROS levels and effectively inducing ferroptosis. Moreover, when the biomimetic ferroptosis nanoparticles were combined with αPD-L1 immunotherapy, PM@ESLNPs significantly inhibited tumor growth and metastasis in liver cancer. In addition, the SPIO contained in PM@ESLNPs could monitor the therapeutic effect in real time by MRI. This method is expected to provide new insights and references for the clinical treatment of tumor proliferation and metastasis. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 : is a preparation and characterization diagram of PM@ESL NPs in an embodiment of the present invention; wherein a is a preparation flow chart of PM@ESLNPs; b is a TEM image; c is a particle size distribution diagram; d is a surface Zeta potential diagram; e is a fluorescence signal diagram; f is an encapsulation efficiency diagram; g is a release diagram of Erastin of PM@ESLNP at pH 6.5 and 7.4; h is the lactate oxidation capacity of lactate oxidase in PM@ESLNPs;

[0026] Figure 2 1 is an in vivo fluorescence imaging and MRI imaging analysis diagram in Example 2 of the present invention; wherein a and c are fluorescence signal accumulation and analysis diagrams of the tumor site caused by intravenous injection of ICG-labeled ESLNP or PM@ESLNP into H22 tumor-bearing mice; b and d are in vitro fluorescence images of tumor tissues and major organs and result analysis diagrams; ef is a change diagram and analysis diagram of the T2-weighted signal in the tumor area from 0 to 8 hours;

[0027] Figure 3 : This is an in vivo anti-tumor efficacy analysis of PM@ESLNPs in Example 3 of the present invention; wherein, a is a diagram of the treatment process of mice; bd are diagrams showing changes in the weight, tumor length and width of mice; e is a diagram showing changes in the lactic acid content in the tumor; f and g are the levels of key iron metabolism factors SLC7A11 and GPX4 in tumor tissue; h is the level of ROS; i is the morphological changes of liver tumor sections detected by H&E staining; j is the apoptosis of tumor cells detected by TUNEL staining;

[0028] Figure 4 is the immune response analysis in Example 4 of the present invention; wherein a is a processing schematic diagram; bd is flow cytometry analysis of dendritic cell (DC) populations in the spleen and CD3 in tumor tissues + CD8 + CD4 + T cells, CD4 + Treg cell analysis diagram; eh is the DC maturity (CD11c + CD80 + CD86 + ), CD3 + CD8 + T cells, CD3 + CD4 + T cells and CD4 + Foxp3 + Quantitative analysis of T cells. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0030] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0031] (1) Lactate oxidase (LOX) was purchased from Yuanye Biotechnology Co., Ltd. (Shanghai). Hoechst 33342, ferroptosis inducer (Erastin), acetylacetonate iron (III) (Fe(acac) 3 ), 1,2-hexadecanediol, oleic acid (90%), diphenyl ether, oleylamine (70%) and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) were purchased from Sigma-Aldrich (USA); phosphate buffered saline (PBS) was purchased from Thermo Fisher Scientific (USA); polyvinyl alcohol (PVA), doxorubicin hydrochloride (DOX), dichloromethane (DCM) and indocyanine green (ICG) were purchased from Aladdin Chemical Company (Shanghai); polylactic-co-glycolic acid (PLGA; lactide: glycolide 50:50, Mw ~ 21,000) was purchased from Daigang Biomaterials Co., Ltd. (Jinan); membrane protein extraction kit and protease inhibitors were purchased from Phygene Life Sciences Co., Ltd (Fuzhou); V-fluorescein isothiocyanate (FITC) apoptosis detection kit and 4',6-diamidino-2-phenylindole (DAPI) were purchased from Bio-Technology Co., Ltd. (Shanghai).

[0032] The antibodies used in the embodiments of the present invention, APC-CD3 mouse antibody (Lot#100236), FITC-CD4 mouse antibody (Lot#100405), PE-CD8a mouse antibody (Lot#100708), FITC-CD11c mouse antibody; Lot#117306), APC-CD80 mouse antibody (Lot#104714) and PE-CD86 mouse antibody (Lot#159204) were all purchased from BioLegend, Inc (USA); mouse PD-L1 checkpoint blocker was purchased from InVivoPlus (Lot#BP0101, B7-H1, Bio cell, USA).

[0033] (2) Animal and tumor models

[0034] Animals: Male BALB / c mice (6-8 weeks old, 20-25 g) were purchased from Shanghai Slack Laboratory Animal Co., Ltd. (Shanghai, China). All animal procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals of Lishui University and approved by the Animal Ethics Committee of Lishui University (SYXK(Zhe)2021-0026).

[0035] Tumor model: A unilateral subcutaneous tumor-bearing mouse model was established by injecting H22 cells into the right leg.

[0036] Example 1 Preparation and characterization of biomimetic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles

[0037] In this example, double emulsion technology was used to synthesize PM-coated multifunctional nanoparticles (PM@ESLNP) loaded with SPIO, lactate oxidase LOX and ferroptosis agonist Erastin ( Figure 1 a), the specific steps are as follows:

[0038] (1) Preparation of lipophilic SPIO particles

[0039] Take 0.706g Fe(acac) 3 , 1.012 g 1,2-hexadecanediol, 2 mL oleic acid and 2 mL oleylamine were dissolved in 20 mL diphenyl ether and refluxed at 100 °C under nitrogen flow for 15 min. Next, the mixture was heated to 200 °C for 30 min, then heated to 265 °C for 30 min, centrifuged and washed to remove impurities to obtain SPIO; it was redispersed in ethanol for later use.

[0040] (2) Preparation of ESLNPs

[0041] 250 μL of LOX aqueous solution (L; 200 μg mL -1 ) was added to 750 μL of dichloromethane containing PLGA (30 mg), Erastin (E; 1 mg) and SPIO (S; 1 mg). The resulting mixture was sonicated for 99 pulses (on for 3 seconds, off for 7 seconds). Then, the obtained emulsion was added to 5 mL of PVA solution (1 wt%) for 5 min of water bath sonication and stirred at room temperature overnight to evaporate the dichloromethane. The obtained ESLNPs were washed 3 times by centrifugation at 14,800 rpm for 30 min to remove excess PVA and free drugs, and then centrifuged at 3000 rpm for 5 min to remove unwanted large particles to obtain ESLNPs.

[0042] In this example, other control nanoparticles were also prepared: they were prepared using a procedure similar to step (2), except that: 1) LOX and SPIO were not added to obtain ENP; 2) SPIO was not added to obtain ELNP; 3) LOX was not added to obtain ES NP.

[0043] (3) Platelet membrane separation

[0044] Anticoagulated blood samples from 20 healthy male BALB / c mice were taken and added to a centrifuge tube containing separation medium (4 mL; mouse peripheral blood platelet separation medium). The samples were centrifuged at 250-300 g for 15 min at room temperature to obtain platelet-rich plasma (PRP) supernatant, and then PRP was diluted with an equal volume of sample diluent (provided in the kit). Centrifuge at 500 g for 20 min, wash the precipitate three times with 5 mL PBS, and then resuspend the precipitate in PBS containing ethylenediaminetetraacetic acid (1 mM) and protease inhibitors (2 mM) to obtain platelets. A suspension of PM fragments was obtained by repeated freezing and thawing and ultrasonic treatment.

[0045] (4) Preparation of PM biomimetic ESL nanoparticles (PM@ESLNPs)

[0046] PBS (2 mL) containing ESLNPs (4 mg) was mixed with PM fragments, sonicated at 100 W and 40 kHz for 5 min, and repeatedly extruded through a 200 nm porous membrane to prepare PM@ESLNPs.

[0047] Reference Figure 1 :Different from ESLNP, PM@ESLNP exhibits a unique core-shell structure with a clearly defined membrane coating on the outside, separated from the NP core ( Figure 1 b). There was no significant difference in the particle sizes of ESLNP and PM@ESL NP, which were 180.6±8.31nm and 184.1±7.79nm, respectively ( Figure 1 c). In addition, the surface Zeta potentials of ESL NP, PM and PM@ESL NP were all negatively charged, which were -3.55±0.98mV, -11.18±1.39mV and -11.55±1.79mV, respectively ( Figure 1 d). The perfect co-localization of ESLNP signals (red fluorescence from Cy5.5) and PM (green fluorescence from DiO-labeled PM) further confirmed the successful coating of PM fragments onto ESLNPs ( Figure 1 e).

[0048] Quantitative analysis showed that the drug loading of Erastin and LOX in PM@ESLNPs was 3.24%±0.12% and 0.167%±0.19%, respectively; the encapsulation efficiency was 93.86%±2.1% and 46.59%±5.3%, respectively. Figure 1 f). In addition, the release of Erastin from PM@ESLNP and ESLNP was studied in vitro in PBS (pH 7.4) at 37°C. The results showed that both had similar release behaviors, indicating that the PM coating did not affect the release of Erastin ( Figure 1 g).

[0049] Example 2 In vivo fluorescence imaging and in vivo MRI imaging of PM@ESLNPs

[0050] H22 tumor-bearing mice were intravenously injected with free ICG, ICG-labeled NPs (ICG NPs), and ICG-labeled PM@NPs (PM@ICG NPs), and in vivo fluorescence imaging was performed. Figure 2 As shown in a and 2c, intravenous injection of ICG-labeled NPs or PM@NPs into H22 tumor-bearing mice resulted in the accumulation of fluorescence signals at the tumor site, reaching a peak at 8 h and then gradually weakening. Notably, the fluorescence intensity of ICG-labeled PM@NPs was significantly more pronounced than that of ICG-labeled NPs. This indicates the effective targeting and accumulation of PM@NPs at the tumor site. 24 h after injection, major organs (heart, liver, spleen, lungs, and kidneys) and tumors were removed for subsequent ex vivo imaging analysis, and the results are shown in Figure 2 b and 2d. It can be seen that the tumor fluorescence intensity of PM@ICGNP far exceeds that of free ICG, highlighting the powerful tumor targeting and retention ability of PM@ESLNP.

[0051] H22 tumor-bearing mice were intravenously injected with 100 μL PBS and PM@ESLNPs (Fe 3 O 4 The MRI images of mice were collected at 0h, 2h, 4h, 8h, 12h and 24h after injection. Figure 2 As shown in Figure ef; it can be seen that after intravenous injection of PM@ESLNPs, the T2-weighted signal in the tumor area gradually decreased from 0 to 8 hours and reached a minimum at 8 hours. In contrast, the ESLNPs group showed no significant signal change in the tumor area. After 8 hours, the T2-weighted signal gradually recovered, indicating that PM@ESLNPs were gradually metabolized in vivo, further confirming the superior ability of PM@ESLNPs for tumor-targeted MRI.

[0052] Example 3 In vivo antitumor efficacy of PM@ESLNPs

[0053] Using a subcutaneous unilateral tumor model, the tumor volume reached 80-100mm 3 Afterwards, the tumor-bearing mice were randomly divided into seven groups (n=5): (I) PBS, (II) ENPs, (III) ES NPs, (IV) ELNPs, (V) ESLNPs, (VI) PM@ESLNPs, and (VII) PM@ESLNPs+αPD-L1. Figure 3 As shown in a. On days 0, 3, and 6, mice were intravenously injected with NP (30 mg kg -1 ), and αPD-L1 (1 mg kg -1The body weight and tumor length (L) and width (W) of each mouse were measured every three days during the treatment period. On day 18, tumor tissues were collected, weighed, and imaged. Figure 3 As shown in bd, compared with PBS treatment, ENPs, ES NPs, ELNPs, and ESLNPs treatment delayed tumor growth to some extent, but PM@ESLNPs treatment controlled tumor progression better than other treatments. PM@ESLNPs and αPD-L1 combined treatment delayed tumor growth to the greatest extent. Moreover, no significant weight changes were observed in the treated mice. In addition, the lactate content in the tumor after different treatments was as shown in Figure 3 As shown in (e), although ENP and ES NPs did not affect the intratumoral lactate content, ELNPs, ESLNPs, and PM@ESLNPs significantly reduced the intratumoral lactate level, indicating that LOX has an excellent ability to reduce the intratumoral lactate level.

[0054] The collected tumor tissue sections were stained with hematoxylin-eosin (H&E) and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL), and the levels of DCFH-DA, GPX4, and SLC7A11 in tumor tissues were quantified using immunofluorescence staining. Immunofluorescence staining showed that the levels of GPX4 and SLC7A11 were the lowest in PM@ESLNPs and PM@ESLNPs+αPD-L1, indicating that PM@ESLNPs can consume GSH and downregulate the expression of GPX4 and SLC7A11 ( Figure 3 fg). DCFH-DA immunofluorescence staining was used to measure the ROS level in tumors. PM@ESLNPs increased ROS production ( Figure 3 h). These results consistently demonstrate that PM@ESL NPs can achieve good antitumor efficacy through ferroptosis induced by the combined effects of GSH / GPX4 inhibition and ROS generation. H&E staining was used to explore the morphological changes of liver tumor sections. The results showed that PM@ESLNPs+αPD-L1 treatment caused more obvious tissue necrosis than other treatments ( Figure 3 i) TUNEL staining to detect apoptosis of tumor cells Figure 3 As shown in (j), treatment with E NPs, ES NPs, ELNPs, ESLNPs, PM@ESLNPs and (VII) PM@ESLNPs+αPD-L1 induced visible cell apoptosis, and cell apoptosis was greatest when PM@ESLNPs were combined with αPD-L1.

[0055] In addition, this example also used a bilateral subcutaneous tumor model to study the therapeutic effect of PM@ESLNPs combined with αPD-L1 immunotherapy on liver cancer. The results showed that the tumor inhibition rate of PM@ESL NPs+αPDL1 on primary tumors was 74.67%±3.08%, and the tumor inhibition rate on distant tumors was 84.45%±5.76%.

[0056] Example 4 Immune Response Analysis

[0057] H22 tumor-bearing mice were treated with PBS, ENPs, ES NPs, ELNPs, ESLNPs, PM@ESL NPs, or PM@ESLNPs+αPD-L1 (1 mg / kg for 24 hours) and injected with the corresponding drugs on days 0, 3, and 6, and then sacrificed on day 9; the obtained tumors and spleens were used for immune mechanism analysis. The specific treatment diagram is shown in Figure 4 a. In a unilateral tumor model, cells within the tumor were stained with fluorescently labeled antibodies to identify cytotoxic T cells (CD3 + CD4 + CD8a + ) and regulatory T (Treg) cells (CD3 + CD4 + FOXP3 + ), and cells in the spleen were stained for dendritic cells (CD11c + CD80 + CD86 + ).

[0058] The results showed that PM@ESLNPs or PM@ESLNPs+αPD-L1 treatment activated DCs more effectively than other treatments, and the proportion of mature DCs was significantly higher ( Figure 4 b and 4e). PM@ESLNPs promoted the expression of T helper cells (CD3 + CD4 + ) and cytotoxicity (CD3 + CD8 + ) Intratumoral infiltration of lymphocytes ( Figure 4 c and 4f-g). In addition, Figure 4 As shown in d and 4h, a large number of Treg cells infiltrated the immunosuppressed tumor. After PM@ESLNPs+αPD-L1 treatment, the proportion of Tregs decreased to 9.71% and 7.44%, respectively, compared with the control group (20.8%). This indicates that PM@ESLNP helps recruit more innate immune cells to the tumor site, overcome immunosuppression, and thus enhance cancer treatment.

[0059] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A bionic ferrocephate nanoparticle loaded with superparamagnetic iron oxide nanoparticles, characterized in that: It comprises an outer shell and an inner core coated in the outer shell; the outer shell is a platelet membrane; the inner core comprises superparamagnetic iron oxide nanoparticles, a ferroptosis inducer and lactate oxidase; the content of the ferroptosis inducer in the bionic ferroptosis nanoparticles is 3.12% to 3.36%, the content of lactate oxidase is 0.167% to 0.325%, and the content of the superparamagnetic iron oxide nanoparticles is 2.42% to 3.57%.

2. The bionic ferrocephate nanoparticle according to claim 1, characterized in that: The ferroptosis inducing agent is selected from Erastin.

3. The bionic ferrocene nanoparticles according to claim 1, characterized in that: The particle size of the bionic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles is 176.31nm-191.89nm.

4. The method for preparing biomimetic ferrocephate nanoparticles loaded with superparamagnetic iron oxide nanoparticles according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) mixing an aqueous solution of lactate oxidase with an organic solvent containing PLGA, a ferroptosis inducer and superparamagnetic iron oxide nanoparticles, and obtaining an emulsion after ultrasonic treatment; stirring the obtained emulsion with a polyvinyl alcohol solution at room temperature to obtain ESLNPs; (2) extracting mouse platelets by gradient centrifugation, and subjecting the extracted platelets to repeated freezing and thawing and ultrasonic treatment to obtain platelet membrane fragments; (3) The buffer solution containing the ESLNPs prepared in step (1) is mixed with the platelet membrane fragments obtained in step (2), and after ultrasonication and extrusion, the bionic ferroptosis nanoparticles PM@ESLNP loaded with superparamagnetic iron oxide nanoparticles are obtained.

5. The preparation method according to claim 4, characterized in that: In step (3), the concentration of ESLNPs in the ESLNPs solution is 1.0 mg / mL to 3.5 mg / mL.

6. An immunogenic cell death inducing agent, characterized in that Biomimetic ferroptotic nanoparticles comprising the superparamagnetic iron oxide nanoparticles loaded as claimed in any one of claims 1 to 3.

7. Use of the bionic ferroptotic nanoparticles loaded with superparamagnetic iron oxide nanoparticles according to any one of claims 1 to 3 in the preparation of anti-tumor drugs.

8. The use according to claim 7, characterized in that: The drug also includes αPD-L1.

9. Use of the bionic ferroptotic nanoparticles loaded with superparamagnetic iron oxide nanoparticles according to any one of claims 1 to 3 in the preparation of tumor nuclear magnetic resonance contrast agents.

10. Use of the bionic ferroptotic nanoparticles loaded with superparamagnetic iron oxide nanoparticles according to any one of claims 1 to 3 in the preparation of anti-tumor metastasis drugs.

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