Iron-doped carbon dot nanoparticles, and preparation method and application thereof

Abstract

The application discloses a composite material and a preparation method and application thereof, and relates to the technical field of composite materials, and specifically discloses a composite material which comprises a coating layer and iron-doped carbon dots encapsulated in the coating layer. The composite material (multifunctional nanoparticles (Fe / CPP NPs)) provided by the application has tumor microenvironment (TME) stimulation response characteristics, can be targeted to reach the position of a tumor to release Fe 3+ , enhance the ferroptosis effect in tumor cells, and realize synergistic treatment of related diseases.

Description

Technical Field

[0001] This invention belongs to the field of targeted tumor therapy technology, specifically relating to a composite material, its preparation method, and its application. Background Technology

[0002] Currently, various combinations of chemotherapy / photothermal therapy (CT / PTT), photothermal / photodynamic therapy (PTT / PDT), and chemotherapy / photothermal / chemodynamic therapy (CT / PTT / CDT) have shown excellent anti-tumor effects. Although multimodal therapies have a killing effect on tumor cells, their efficacy remains limited due to inherent physiological barriers in the tumor microenvironment (TME), such as hypoxia, overexpression of hydrogen peroxide (H2O2), and glutathione (GSH).

[0003] Carbon nanodots (CDs) are carbon nanomaterials smaller than 10 nm, typically composed of carbon, hydrogen, and oxygen, discovered in the early 21st century. Due to their low preparation cost, small size, good water solubility, pharmaceutical activity, and high biocompatibility, carbon nanodots have demonstrated unique advantages and promising applications in the biomedical field.

[0004] Currently, research on the application of carbon dots in tumor diagnosis and treatment is still in the exploratory stage. Some researchers have used gels to encapsulate carbon dots and doxorubicin for imaging and tumor treatment. In these cases, the carbon dots serve only as the center for fluorescence imaging, while tumor treatment mainly relies on the chemotherapeutic effect of doxorubicin. In other words, existing carbon dot technology cannot meet the needs for effective treatment targeting the complex tumor microenvironment, and the expansion of treatment modalities remains limited to co-loading anticancer drugs (such as doxorubicin). Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems existing in the prior art. To this end, the present invention provides a composite material, its preparation method and application.

[0006] According to one aspect of the present invention, a composite material is provided, comprising: a coating and iron-doped carbon dots encapsulated within the coating.

[0007] Preferably, the coating contains PAE-PEG.

[0008] Preferably, glutathione can trigger the dissociation of the iron-doped carbon dots.

[0009] According to another aspect of the present invention, a method for preparing the above-mentioned composite material is provided, comprising: preparing iron-doped carbon dots; and encapsulating the iron-doped carbon dots.

[0010] Preferably, the preparation of iron-doped carbon dots includes: adding aniline and ammonium persulfate to an aqueous solution A containing amino acids and ferric nitrate to obtain a precipitate; dissolving the precipitate and then subjecting it to a hydrothermal reaction, filtration, dialysis, and drying to obtain the iron-doped carbon dots, wherein the amino acid is histidine.

[0011] Preferably, encapsulating the iron-doped carbon dots includes: mixing an aqueous solution B containing the iron-doped carbon dots and a chloroform solution C containing PAE-PEG to obtain a mixed solution; mixing the mixed solution with a PVA aqueous solution and then homogenizing, evaporating, and centrifuging to obtain a coating encapsulating the iron-doped carbon dots.

[0012] Preferably, the aniline and the ammonium persulfate are added to solution A in sequence while being stirred.

[0013] Preferably, the hydrothermal reaction conditions include a temperature of 260°C and a time of 12 hours.

[0014] Preferably, dialysis is performed using 800-1000 Da dialysis bags.

[0015] According to another aspect of the present invention, the use of the above-described composite material in the preparation of a tumor-treating drug is provided.

[0016] Preferably, the tumor is a melanoma.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The composite material provided by the present invention effectively solves the limitation of treatment methods by inherent physiological barriers in the tumor microenvironment (TME) (such as hypoxia and overexpression of hydrogen peroxide (H2O2) and glutathione (GSH). On the other hand, it also promotes the decline of intracellular antioxidant capacity and the accumulation of lipid reactive oxygen species (ROS), and promotes ferroptosis.

[0018] The Fe / CPP NPs constructed in this experiment are encapsulated in PAE-PEG, an acid-triggered degradation material that releases FeCDs under the low pH conditions of the tumor microenvironment. FeCDs possess dual GSH-consuming capabilities: firstly, the carbon dots prepared using histidine as the carbon source inherently possess GSH-consuming capabilities; secondly, Fe... 3+ The introduction of this technology can amplify the GSH consumption capacity of carbon dots.

[0019] The composite material disclosed in this invention can release iron-doped carbon dots in the tumor microenvironment (TME). Glutathione (GSH) further induces the effective dissociation and reduction of the iron-doped carbon dots, and the reduced Fe... 2+This composite material effectively catalyzes the generation of hydroxyl radicals (·OH) from H₂O₂. While achieving the therapeutic effects of chemokinetic therapy (CDT) and amplified intracellular oxidative stress, it also significantly increases the accumulation of lipid reactive oxygen species (ROS), promoting ferroptosis. In other words, this invention provides a targeted tumor synergistic therapy solution, effectively addressing the problem that existing technologies cannot effectively treat complex tumor microenvironments. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0021] Figure 1 The diagram shows the morphological characteristics of iron-doped carbon dots (FeCDs) in Embodiment 1 of the present invention;

[0022] Figure 2 The results of the stimulation-response characteristics of iron-doped carbon dots (FeCDs) and composite materials (Fe / CPP NPs) in Example 1 of the present invention are shown.

[0023] Figure 3 The cell screening process, cell internalization method, and cell ROS level measurement results of the in vitro experiment in Example 2 of the present invention are shown.

[0024] Figure 4 The results of the cell hemolysis experiment using the composite material in Example 3 of the present invention are shown;

[0025] Figure 5 The in vivo experimental results of Example 3 of the present invention are shown, including the determination of tumor growth, the detection of mouse body weight, and the determination of tumor size and weight; and

[0026] Figure 6 The results of H&E staining of organs, tissues and tumors in Example 3 of the present invention are shown. Detailed Implementation

[0027] The following examples are provided to help those skilled in the art better understand the present invention. It should be noted that the following examples are not intended to limit the scope of protection claimed by the present invention, but are merely illustrative. Unless otherwise specified, the raw materials, reagents, or devices mentioned in the following examples are commercially available or obtained through known existing methods.

[0028] This invention provides a composite material, its preparation method, and its application in tumor therapy. The composite material (multifunctional nanoparticles (Fe / CPP NPs)) possesses tumor microenvironment (TME) stimulation-responsive properties, enabling it to target and release Fe at the tumor site. 3+ It enhances the ferroptosis effect in tumor cells.

[0029] Ferroptosis is an iron-dependent, novel form of programmed cell death, distinct from apoptosis, necrosis, and autophagy. The main mechanism of ferroptosis involves lipid peroxidation of highly expressed unsaturated fatty acids on the cell membrane, catalyzed by ferrous iron or esteroxygenases, leading to cell death. Furthermore, it is characterized by a decrease in GPX4, a core enzyme regulating the antioxidant system (glutathione system). Triggered ferroptosis can be used in cancer treatment, particularly for eradicating aggressive malignancies resistant to conventional therapies.

[0030] The composite material provided by this invention includes: a coating and iron-doped carbon dots encapsulated within the coating. A method for preparing the composite material includes: preparing iron-doped carbon dots; and encapsulating the iron-doped carbon dots. Considering Fe... 3+ The coordination ability with the abundant functional groups on the CDs surface, through the assembly of Fe 3+ Modified CDs and PAE-PEG (FeCDs@PAE-PEG) were used to prepare multifunctional nanoparticles (named Fe / CPP NPs) with TME-stimulated response.

[0031] Specifically, the preparation of composite materials (multifunctional nanoparticles (named Fe / CPP NPs)) includes the following steps.

[0032] (1) Dissolve amino acids and ferric nitrate in water, then add aniline and ammonium persulfate and react for 4 hours to obtain a precipitate. The amino acid is histidine and the ferric nitrate is Fe(NO3)3·9H2O.

[0033] (2) Dissolve the obtained precipitate in water and heat it in air at 260°C for 12 hours using a hydrothermal method;

[0034] (3) After filtering the obtained solution through a 0.22 μm filter membrane, dialyze the solution using a dialysis membrane (MWCO: 500-1000);

[0035] (4) The dialysate was vacuum dried to obtain a powder (brown powder), and iron-doped carbon dots were prepared.

[0036] (5) Dissolve iron-doped carbon dots in water and add them to polyacetal-polyethylene glycol (PAE-PEG) dissolved in chloroform to obtain a mixture;

[0037] (6) The mixture was homogenized with a polyvinyl alcohol (PVA) solution, and the organic solvent was evaporated at 25°C and then centrifuged to obtain Fe / CPPNPs.

[0038] The Fe / CPP NPs prepared by the above method can release FeCDs in the tumor microenvironment (TME), and the presence of GSH can induce Fe... 3+ Effective dissociation and reduction of Fe. GSH will... 3+ Reduced to Fe 2+ After that, Fe 2+ The Fenton reaction effectively catalyzes H2O2 and generates hydroxyl radicals (·OH).

[0039] The present invention also provides a method for targeted and synergistic treatment of tumors, comprising the following steps.

[0040] Detection of S1.Fe / CPP nanoparticles: including Fe in FeCDs 3+ The determination of dissociation content, measurement of GSH consumption, weak acid-stimulated decomposition of Fe / CPP NPs, and chemokinetic activity assay of FeCDs were performed.

[0041] S2. In vitro experiments, including cell culture and type selection, cytotoxicity assays, determination of cell uptake patterns, and detection of reactive oxygen species (ROS) in cells.

[0042] S3. In vivo experiments, including adaptive feeding, inoculation and treatment of mice, hemolysis test of materials, histological staining test, and Western blot verification.

[0043] In step S1, in order to measure the Fe triggered by GSH 3+ The FeCDs and GSH were dispersed in PBS solution for reduction. The mixture was then dialyzed, and the dialysate was mixed with a 1,10-phenanthroline solution and incubated at room temperature.

[0044] In step S1, 5,50-dithiobis(2-nitrobenzoic acid) (DTNB) was used to study the GSH activity level.

[0045] In step S1, to determine the release of pH-activated FeCDs, Fe / CPP NPs were dissolved in the appropriate release buffers (pH 7.4, pH 6.8, and pH 5.5 PBS buffers).

[0046] In step S1, CDT activity was detected by catalyzing the oxidation of H2O2 in the presence of FeCDs using 3,3',5,5'-tetramethylbenzidine (TMB) as a peroxidase substrate. The CDT activity of FeCDs was analyzed by measuring the yield of 2-hydroxyterephthalic acid.

[0047] In step S2, four different cell lines were selected, including the 4T1 mouse breast cancer cell line (4T1), the B16F0 mouse melanoma cell line (B16F0), the human liver cancer cell line (HepG2), and the human colorectal adenocarcinoma cell line (HT-29).

[0048] In step S2, the cytotoxicity assay was performed using the MTT assay.

[0049] In step S2, the fluorescent probe CM-H2DCFA is used to monitor the generation of ROS.

[0050] In step S3, B16F0 cells (50 μL, 1 × 10⁻⁶ cells) suspended in PBS are... 6 The cells / mL were subcutaneously injected into mice. The mice were used for in vivo studies 10 days after tumor growth.

[0051] The approved protocol in step S3 specifies a maximum tumor size of 100 mm. 3 Or larger, lasting for 3 days with no signs of abating.

[0052] In step S3, to evaluate the in vivo antitumor effect, B16F0 tumor-bearing mice were randomly divided into three groups and received the following treatments: (1) intraperitoneal injection of PBS, (2) intraperitoneal injection of CPP NPs (60 μL, 12.5 mg / mL) only. -1 (3) Fe / CPPNPs (60 μL, 12.5 mg / mL) were injected via ip only. -1 Tumor volume and mouse weight were recorded regularly until day 15 post-treatment.

[0053] In step S3, mice were sacrificed on day 15 post-treatment to harvest tumors and major organs. Finally, the tissues were embedded, sectioned, and stained with hematoxylin and eosin (H&E) for observation.

[0054] The present invention provides the following specific embodiments.

[0055] Example 1

[0056] This embodiment provides a composite material, including: a coating and iron-doped carbon dots encapsulated within the coating. Specifically, it provides an assembly of Fe... 3+ Modified CDs and PAE-PEG (FeCDs@PAE-PEG) were used to prepare multifunctional nanoparticles (named Fe / CPP NPs) with TME stimulus response. The preparation method includes the following steps.

[0057] (1) Dissolve histidine and ferric nitrate in water, then add aniline and ammonium persulfate and react for 4 hours to obtain a precipitate;

[0058] (2) Dissolve the obtained precipitate in water and heat it in air at 260°C for 12 hours using a hydrothermal method;

[0059] (3) After filtering the obtained solution through a 0.22 μm filter membrane, dialyze the solution using a dialysis membrane (MWCO: 500-1000);

[0060] (4) The dialysate was vacuum dried to obtain powder, and iron-doped carbon dots were prepared.

[0061] (5) Dissolve iron-doped carbon dots in water and add them to PAE-PEG dissolved in chloroform to obtain a mixture;

[0062] (6) Homogenize the mixture with PVA solution, evaporate the organic solvent at 25°C and centrifuge to obtain Fe / CPPNPs.

[0063] Carbon dots prepared using different carbon sources will exhibit varying or even no activity. Using a histidine (His)-Fe(NO3)3 complex as a precursor, ammonium persulfate as an initiator, and aniline as a reducing agent, a poly(His)-iron complex was prepared via in-situ polymerization. Then, using the prepared complex as a precursor, FeCDs were synthesized via a hydrothermal method, with ammonium persulfate as the initiator and aniline as the reducing agent; this order is crucial. 3+ The introduction of this compound amplifies the GSH-consuming capacity, while simultaneously reacting in situ with excess H2O2 in the TME to generate highly oxidized ·OH. This synergistic self-amplification therapy strategy for cancer treatment exerts its therapeutic effect through the dual consumption of GSH. TEM images show that the synthesized Fe / CPP NPs exhibit a well-defined spherical core-shell shape and a uniform size of approximately 50 nm. Figure 1 A). Furthermore, the average hydrodynamic diameter of Fe / CPP NPs measured by DLS is approximately 50 nm ( Figure 1 C). As shown in the HRTEM images, FeCDs exhibit a unique crystal structure and are well dispersed, with an average diameter of 2.6 nm. Figure 1 B). Due to the amount of carboxyl (-COOH) groups attached to the surface, CDs exhibit a negative zeta potential (-11.53 mV). When combined with Fe... 3+ Upon binding, the negative zeta potential of FeCDs increases to -4.56 mV. The zeta potential of Fe / CPP NPs was measured to be 5.10 mV. Figure 1 D).

[0064] Example 2

[0065] The stimulus-response properties of multifunctional nanoparticles (named Fe / CPP NPs) include the following steps.

[0066] (1)Fe in FeCDs 3+Determination of dissociation content;

[0067] (2) Measurement of GSH consumption;

[0068] (3) Decomposition of Fe / CPP NPs in response to weak acid stimulation;

[0069] (4) Chemokinetic therapeutic activity of FeCDs.

[0070] In Example 1, there was no Fe 3+ The modified CDs samples were prepared under the following conditions: histidine was dissolved in water and subjected to a hydrothermal method under high temperature and pressure to obtain a brown solution. The resulting solution was filtered through a 0.22 μm filter membrane, and the filtered solution was dialyzed against ultrapure water through a dialysis membrane (MWCO: 500-1000 Da) and then frozen.

[0071] Fe in FeCDs 3+ Determination of dissociation content: Fe 3+ It can consume GSH to revert itself to Fe. 2+ And oxidize GSH to L(-)-glutathione (oxidized form) (GSSG). 3+ The reduction was evaluated using 1,10-phenanthroline, which reacts with Fe... 2+ The reaction produces an orange complex that exhibits absorbance at 512 nm. Figure 2 A). The solution color can be clearly seen changing from transparent to orange, and a characteristic peak appears at 512 nm using UV-Vis detection, proving that Fe... 3+ It has been reduced. GSH-triggered Fe was evaluated by UV-Vis spectroscopy. 3+ Accurate quantification of release amount. 1 mg / mL -1 FeCDs release Fe at 24 hours 3+ The amount was 7.08 ± 1.41 μg / mL. -1 This indicates that the presence of GSH can induce Fe 3+ Effective dissociation and reduction.

[0072] Measurement of GSH consumption: In the presence of thiol groups, colorless DTNB is converted to yellow 5-mercapto-2-nitrobenzoic acid, which exhibits maximum absorption at 412 nm. Fe 3+ The redox reaction between GSH and GSH can also lead to GSH depletion, which can be demonstrated by the change in the GSSG / GSH ratio in the GSH solution using a commercial assay kit. Figure 2 B). Due to Fe 3+A redox reaction occurs between FeCDs and GSH, and GSH consumption increases with the concentration of FeCDs. Meanwhile, histidine does not have the ability to consume GSH, while CDs have some ability to consume GSH, but not as much as FeCDs. Figure 2 C). This property is significant for improving the efficiency of ROS-based tumor therapy because GSH is a well-known ROS scavenger in biological systems. GSH can remove Fe... 3+ Reduced to Fe 2+ Meanwhile, H in acidic media + The electrostatic repulsion between Fe and metal ions is enhanced, weakening Fe 3+ The coordination ability with CDs leads to the disintegration of Fe / CPP NPs.

[0073] Weakly acidic stimuli-responsive decomposition of Fe / CPP NPs: Fe / CPP NPs exhibit an acidic pH-responsive drug release pattern. Figure 2 (D) Within 2 hours, approximately 23.80 ± 1.48% of the Fe / CPP NPs were released at pH 5.5, and approximately 50.50 ± 0.88% were released within 24 hours. However, at the physiological pH of 7.4, only 3.20 ± 0.27% was released within 2 hours, followed by a slower release (~13.80 ± 0.36%) within 24 hours. This phenomenon can be attributed to the pH dependence of the outer coating material PAE-PEG.

[0074] The chemokinetic activity of FeCDs: Iron-containing materials can effectively catalyze H₂O₂ and generate hydroxyl radicals (·OH) in a weakly acidic medium via a Fenton-like reaction. FeCDs can promote the oxidation of TMB, producing a blue substance with ultraviolet absorption at 652 nm mediated by H₂O₂. The intensity of the absorption peak is directly proportional to the concentration of FeCDs. With increasing FeCD concentration, the amount of blue product also increases. Figure 2 E). The ·OH generation characteristics of FeCDs can be determined using disodium terephthalate (TA) as a specific probe. ·OH generation is assessed based on the fluorescence intensity of HA, as the reaction of TA with ·OH produces highly fluorescent 2-hydroxyterephthalic acid (HA). For example... Figure 2 As shown in Figure F, when the amount of FeCDs added is constant, the fluorescence intensity increases with decreasing solution pH, indicating that acidic catalytic conditions favor the reaction, and that FeCDs respond to acidic TME. The results show that FeCDs can catalyze the decomposition of H2O2 into ·OH in the acidic environment of the tumor, thereby initiating CDT. Furthermore, the FL intensity from the mixture of TA, H2O2, and FeCDs was found to be much stronger than that from CDs, verifying the efficient response to H2O2 to generate ·OH and the subsequent CDT capability of FeCDs.

[0075] Example 3

[0076] This embodiment provides a targeted tumor synergistic therapy scheme, including melanoma and Fe / CPP NPs prepared in Example 1. The targeted tumor synergistic therapy scheme includes the following steps.

[0077] (1) Cell culture and type selection;

[0078] (2) Cytotoxicity assay;

[0079] (3) Determination of cellular uptake patterns;

[0080] (4) Detection of reactive oxygen species (ROS) in cells.

[0081] For in vitro CDT, cell viability after incubation with histidine, CDs, and FeCDs was studied using MTT assay. The cytotoxicity of different concentrations of histidine, CDs, and FeCDs on four cancer cell lines was also investigated. Figure 3 As shown in AD. It can be seen that even when the histidine concentration reaches 800 μg / mL... -1 The survival rate of all four cell types remained above 80%. Conversely, with increasing FeCDs and CDs concentrations, the cell viability of B16F0 cells rapidly decreased. (45.55 μg / mL) -1 FeCDs and 91.47 μg mL -1 The IC50 value of FeCDs reached that of B16F0 cells, indicating that FeCDs were more cytotoxic to B16F0 cells than other cancer cells. Therefore, B16F0 cells were chosen as the cell model for subsequent experiments. This finding may be attributed to the promotion of ·OH production through the Fenton reaction and GSH consumption under specific TME conditions. Cell internalization was studied by incubating B16F0 cells with CDs or FeCDs for 4 hours and imaging with confocal laser scanning microscopy (CLSM). CDs and FeCDs are distributed in the cytoplasm, aggregate on the cell membrane, and do not enter the nucleus. Strong fluorescent signals from the cores of CDs or FeCDs can be visualized in the cytoplasm of CDs or FeCDs-treated B16F0 cells, indicating that CDs or FeCDs in B16F0 cells undergo efficient endocytosis via an energy-dependent endocytic pathway. Figure 3E). However, CDs showed poorer cell imaging, possibly because the large amount of -COOH on the surface prevented CDs from entering the cell. FeCDs showed better cell imaging than CDs, which can be attributed to the role of iron as a channel to the enzyme center, positively promoting cell uptake of more FeCDs. Furthermore, 2,7-dichlorofluorescein diacetate (DCFH-DA) was used as a FL indicator to further estimate cellular ROS levels. As expected, both CDs and FeCDs increased ROS in a dose-dependent manner. No significant ROS generation was observed in the control group, but cell ROS increased significantly after culturing with different concentrations of FeCDs and CDs for 30 min, indicating the generation of ·OH. The stronger ability to generate ROS after cell treatment with FeCDs suggests the presence of ·OH and 1 The combination of O2 and O2 effectively increased ROS stress. FeCDs group and CDs group (40 μg·mL⁻¹) -1 The ROS levels of the two groups were approximately 3-fold and 2-fold higher than those of the control group, respectively. Overall, CDs and FeCDs exhibited TME-stimulated FL imaging and synergistic CDT antitumor characteristics in vitro, demonstrating good selectivity.

[0082] Example 4

[0083] This embodiment provides a targeted tumor synergistic therapy scheme, including melanoma and Fe / CPP NPs prepared in Example 1. The targeted tumor synergistic therapy scheme includes the following steps.

[0084] (1) Adaptive feeding, inoculation and drug treatment of mice;

[0085] (2) Hemolysis test of materials;

[0086] (3) Histological staining test;

[0087] (4) Western blot verification.

[0088] The hemocompatibility of CDs, FeCDs, CPP NPs, and Fe / CPP NPs was assessed using a hemolysis test to determine their safety in antitumor applications. Even at 200 μg / mL... -1 At the highest concentrations, CDs, FeCDs, CPP NPs, and Fe / CPPNPs also exhibited low hemolytic activity (<5%) (Table 1). Compared to the positive group, no significant erythrocyte coloration was observed in CDs, FeCDs, and Fe / CPP NPs, indicating that the nanocomponents possess high blood compatibility. Figure 4 ).

[0089] During tumor treatment, the tumor size and body weight of each mouse were measured every three days. Figure 5 A). Tumor growth inhibition curves of different treatment groups as shown in the figure. Figure 5 As shown in Figure B, the tumor growth curves clearly demonstrate that Fe / CPP NPs have a significant and statistically significant effect on tumor treatment. The CPP NPs group showed some inhibitory effect on tumor growth, but this was far less than that of the Fe / CPP NPs group. Neither the Fe / CPP NPs nor the CPP NPs group experienced significant weight loss during treatment. It only decreased slightly after the first dose and then returned to normal growth. Figure 5 C). By isolating tumor tissue from each group, the tumor size and weight of all mice were as follows: Figure 5 As shown in D and 5E, the tumor weight and size in the Fe / CPP NPs group were significantly lower than those in the PBS group, suggesting that Fe / CPP NPs can achieve anti-tumor effects in vivo. The mean tumor weight was 2.79±0.49g in the PBS group, 1.55±0.31g in the CPP NPs group, and 0.58±0.11g in the Fe / CPP NPs group (Table 2).

[0090] Table 1. Hemolysis assays for CDs, FeCDs, CPP NPs, and Fe / CPP NPs

[0091]

[0092]

[0093] Histological studies are more reliable in examining the toxicity of Fe / CPP NPs and CPP NPs to mouse organs. To verify the therapeutic effect, tumors were obtained from mice to assess cancer cell apoptosis. H&E staining of tumor sections from different groups of mice revealed active proliferation and significantly blue-stained nuclei in the PBS group. In contrast, cancer cell nuclei in the Fe / CPP NPs group showed condensation, shrinkage, and dark staining, with even the presence of erythrocytes in the intercellular matrix, indicating significant apoptosis and necrosis of the cancer cells. Clearly, apart from the tumor, all mouse organs (liver, heart, kidney, lung, spleen) in the Fe / CPP NPs group were similar to those in the PBS group, showing no significant histopathological abnormalities. Therefore, Fe / CPP possesses antitumor activity and is non-toxic to viscera.

[0094] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0095] (1) This invention constructs an intelligent anticancer therapy platform by easily assembling Fe / CPP NPs. This platform exhibits significant characteristics of TME stimulation response and enhanced CDT synergistic therapy. Notably, Fe... 3+ The introduction of this not only provides CDT function (by reacting with H2O2 to produce ·OH), but also effectively consumes GSH in the tumor, leading to amplification of intracellular oxidative stress and enhancing ROS-related therapeutic efficiency.

[0096] (2) Activation of ROS-related therapies was observed in vitro, with enhanced therapeutic effects only against cancer cells. In vivo results confirmed that Fe / CPP NPs had improved accumulation capacity at tumor sites and exhibited excellent anti-tumor effects with minimal systemic toxicity. This invention proposes a strategy to address the small size limitation of CDs in tumor biomedicine, and develops a targeted tumor synergistic therapy by fully utilizing TME.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing iron-doped carbon dot nanoparticles, characterized in that, include: Aniline and ammonium persulfate were added sequentially to an aqueous solution A containing histidine and ferric nitrate to obtain a precipitate; The precipitate was dissolved and subjected to hydrothermal reaction, filtration, dialysis and drying to obtain iron-doped carbon dots. The hydrothermal reaction conditions included a temperature of 260°C and a time of 12 hours. Dialysis is performed using a 500-1000 Da dialysis membrane; An aqueous solution B containing the iron-doped carbon dots and a chloroform solution C containing PAE-PEG were mixed to obtain a mixed solution; The mixed solution was mixed with PVA aqueous solution and then homogenized. After evaporating the organic solvent, the mixture was centrifuged to obtain iron-doped carbon dot nanoparticles Fe / CPPNPs.

2. The application of the iron-doped carbon nanoparticles prepared according to claim 1 in the preparation of drugs for treating tumors, wherein the tumor is selected from breast cancer, melanoma, hepatocellular carcinoma, and colorectal adenocarcinoma.

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