Iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles, preparation method and application thereof

Abstract

The application discloses an iron-sulfasalazine / arteannuin ternary coordination polymer nanoparticle, a preparation method and application thereof, and a preparation process as follows: Fe 3+ Ions are self-assembled with sulfasalazine in an alkaline medium to construct an amorphous Fe-SASP precursor; arteannuin is hydrolyzed to have a carboxyl group; the hydrolyzed arteannuin is mixed with the Fe-SASP precursor, and a coordination action of the carboxyl group and an unsaturated Fe 3+ site drives a dissolution-recrystallization process to form a Fe-SASP / ART ternary coordination polymer nanoparticle with an ordered crystalline framework. The iron-sulfasalazine / arteannuin nanoparticle has the photo-thermal conversion performance, the photodynamic activity, the oxygen-independent carbon-centered radical generation ability, the self-sustaining Fe 3+ / Fe 2+ redox cycle-mediated delayed radical generation ability, the anti-inflammatory activity and the ability of promoting keratinocyte proliferation by taking the arteannuin as a structure inducer and a co-ligand, so that the nanoparticle can treat acne through a photo-thermal / photodynamic synergistic antibacterial, anti-inflammatory and repair-promoting mechanism.

Description

Technical Field

[0001] This invention belongs to the field of nanomedicine and biomaterials technology, specifically relating to an iron-sulfasalazine / artemisinin (Fe-SASP / ART) ternary coordination polymer nanoparticle, its preparation method and application. Background Technology

[0002] Acne is a global, chronic inflammatory skin disease affecting up to 80% of adolescents and young adults. Propionibacterium acnes (…) Propionibacterium acnes Infection is a major contributing factor to its pathogenesis. Excessive sebum secretion and follicular blockage create a favorable proliferative microenvironment, leading to tissue damage and inflammatory responses. Currently, topical antibacterial and anti-inflammatory drugs are the main clinical treatments, but their efficacy is limited by the skin barrier, and frequent administration leads to poor compliance and significant side effects. Therefore, there is an urgent need to develop safe and effective new strategies.

[0003] In recent years, photoactivated antibacterial therapies (including photothermal therapy and photodynamic therapy) have emerged as promising alternatives to antibiotics. However, conventional photothermal therapy (>60°C) can easily damage surrounding healthy tissue, while milder temperature photothermal therapy (<50°C) can enhance the antibacterial effects of other modalities while reducing thermal damage. Photodynamic therapy, being oxygen-dependent, is limited in its effectiveness in the hypoxic microenvironment preferred by Propionibacterium acnes. Although the integration of both approaches has synergistic potential, challenges remain, including poor water solubility, toxicity, limited skin penetration, immediate termination of efficacy after light irradiation, and the potential for excessive inflammation to exacerbate acne. Therefore, an ideal phototherapy agent for acne should integrate good biocompatibility, targeted follicular penetration, sustained post-light-irradiation antibacterial activity, and inherent anti-inflammatory effects.

[0004] Metal-organic coordination polymers integrate metal ions with therapeutic agents through coordination bonds, enabling multimodal therapeutic functions. Iron ions are widely used as metal centers due to their biocompatibility and Fenton-like reactivity. Artemisinin contains a peroxy bridge, allowing it to connect via Fe... 2+ It mediates cleavage to generate carbon-centered free radicals, and its oxygen-independent generation characteristics allow it to maintain antibacterial effects in anaerobic environments, while causing irreversible alkylation damage to bacterial DNA and proteins. Sulfasalazine is a classic anti-inflammatory drug, but its poor water solubility and insufficient accumulation at lesion sites limit its application. The inventors discovered that Fe... 3+ Coordination with sulfasalazine endows it with photoresponsive properties. Inspired by this, the inventors incorporated artemisinin into Fe-SASP coordination polymers to address key limitations of photoactivated antibacterial therapy through multiple synergistic mechanisms. Summary of the Invention

[0005] The purpose of this invention is to provide an iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticle, its preparation method, and its applications. The Fe-SASP / ART nanoparticles prepared by this invention can, through artemisinin as a structure inducer and co-ligand, endow the nanoparticles with photothermal conversion properties, photodynamic activity, oxygen-independent carbon center free radical generation ability, and self-sustaining Fe... 3+ / Fe 2+ It possesses the ability to generate delayed free radicals mediated by redox cycles, anti-inflammatory activity, and the ability to promote keratinocyte proliferation, thereby treating acne through multiple mechanisms of photothermal / photodynamic synergistic antibacterial, anti-inflammatory, and repair-promoting effects.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles includes the following steps: (1) Dissolve sulfasalazine (SASP) in an alkaline medium and add Fe while stirring. 3+ Stir for 20-40 minutes to obtain an amorphous iron-sulfasalazine (Fe-SASP) precursor; wherein, Fe... 3+ The molar ratio of SASP to SASP is (0.5~1):(0.1~1). (2) Dissolve artemisinin (ART) in ethanol, add alkaline solution and hydrolyze at 40~80℃ for 0.5~4 hours to give it a carboxyl group; (3) The hydrolyzed artemisinin obtained in step (2) is added to the Fe-SASP precursor obtained in step (1), stirred for 0.5 to 2 hours, and then centrifuged, washed, and dried to obtain iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles; wherein the molar ratio of iron-sulfasalazine nanoparticles to artemisinin is (1~2):1. This step involves the interaction of carboxyl groups with unsaturated Fe... 3+ The coordination of the sites drives the dissolution-recrystallization process, forming Fe-SASP / ART ternary coordination polymer nanoparticles with an ordered crystalline framework.

[0007] Further, in steps (1) and (2), the alkaline medium and alkaline solution are selected from at least one of NaOH solution, KOH solution and Na2CO3 solution, the concentration of the alkaline medium is 20~30 mM, the concentration of the alkaline solution is 0.1~1 M, the concentration of sulfasalazine in the alkaline medium is 0.01~0.03 M, and the molar ratio of artemisinin to the alkali in the alkaline solution is 1:(1~3).

[0008] Further, in step (1), the Fe 3+ It is derived from FeCl3 solution, with a concentration of 50~100 mM.

[0009] Furthermore, in step (3), the washing is performed by washing with distilled water 2 to 4 times, and the drying temperature is 55 to 65°C.

[0010] The above preparation method yields iron-sulfasalazine / artemisinin (Fe-SASP / ART) ternary coordination polymer nanoparticles.

[0011] Furthermore, the nanoparticles have a spherical structure, an average particle size of 50-150 nm, and a specific surface area of ​​50-200 m². 2 g -1 The total pore volume is 0.2~1.5 cm³. 3 g -1 .

[0012] Furthermore, artemisinin in the nanoparticles acts as a structure inducer and co-ligand, transforming the amorphous Fe-SASP precursor into an ordered crystalline framework.

[0013] Furthermore, the nanoparticles simultaneously generate photothermal and photodynamic effects through a ligand-metal charge transfer mechanism under near-infrared (NIR) irradiation.

[0014] Furthermore, the nanoparticles generate superoxide anion radicals (•O2) under near-infrared light irradiation. - The free radicals include carbon-centered radicals (•CH3), methoxy radicals (•OCH3), and hydroxyl radicals (•OH), among which the generation of carbon-centered radicals, methoxy radicals, and hydroxyl radicals does not depend on oxygen.

[0015] Furthermore, the nanoparticles, after near-infrared light irradiation ceases, retain Fe... 3+ / Fe 2+ The redox cycle continuously catalyzes the cleavage of artemisinin to generate free radicals, which lasts for 10 to 60 minutes.

[0016] The application of the above-mentioned iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles in the preparation of acne treatment drugs, such as... Figure 1 As shown, the nanoparticles synergistically treat acne through multiple mechanisms, including photothermal therapy, photodynamic therapy, iron-activated artemisinin-mediated oxygen-independent free radical generation, self-sustaining redox cycle-mediated delayed sterilization, anti-inflammation, and promotion of keratinocyte proliferation.

[0017] Furthermore, the nanoparticles are subjected to near-infrared light irradiation via Fe... 2+ Catalyzing the peroxy bridge cleavage within artemisinin generates carbon-centered free radicals, achieving oxygen-independent sterilization.

[0018] Furthermore, the nanoparticles are self-supporting Fe 3+ / Fe 2+The redox cycle continues to catalyze the cleavage of artemisinin to generate free radicals after near-infrared light irradiation stops, thus achieving a delayed bactericidal effect.

[0019] Furthermore, the nanoparticles, through the inherent anti-inflammatory activity of sulfasalazine, inhibit the expression of the NF-κB pathway and pro-inflammatory factors such as TNF-α and IL-1β, thereby alleviating the inflammatory response.

[0020] Furthermore, the nanoparticles promote the proliferation of keratinocytes through the stimulant effect of toxins, achieving a cell viability of 100-150%, and also promote the secretion of epidermal growth factor, accelerating tissue repair.

[0021] Furthermore, the nanoparticles, when applied topically, can be targeted and delivered to hair follicles with a penetration depth of 0-600 μm, providing a controllable penetration depth and avoiding the risk of systemic absorption.

[0022] The above-mentioned iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles are used in the preparation of anti-inflammatory or antioxidant drugs.

[0023] The application of the above-mentioned iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles in the preparation of antibacterial drugs, wherein the antibacterial drugs are effective against Propionibacterium acnes (… Propionibacterium acnes It has a killing effect.

[0024] Compared with existing technologies, the iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles provided by this invention can synergistically treat acne through multiple mechanisms, including photothermal / photodynamic synergistic antibacterial, anti-inflammatory, and repair-promoting effects. The nanoparticles are of suitable size, ensuring targeted delivery to hair follicles with controllable penetration depth, avoiding penetration of the entire dermis to prevent systemic absorption risks, and exhibiting good biocompatibility and application prospects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the working principle of Fe-SASP / ART nanoparticles prepared in Example 1 of the present invention and their treatment of acne. Figure 2 This is a scanning electron microscope (SEM) image of the Fe-SASP / ART nanoparticles prepared in Example 1 of the present invention; Figure 3 This is a transmission electron microscope (TEM) image of the Fe-SASP / ART nanoparticles prepared in Example 1 of the present invention; Figure 4 X-ray diffraction (XRD) patterns of Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention; Figure 5The nitrogen adsorption-desorption isotherms of Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention are shown below. Figure 6 Fourier transform infrared (FTIR) spectra of SASP, Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention; Figure 7 The X-ray photoelectron spectroscopy (XPS) spectra of Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention are shown. Figure 8 The high-resolution X-ray photoelectron spectra of Fe 2p nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention are shown. Figure 9 The image shows the photothermal heating curves of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention at different concentrations. Figure 10 The photothermal stability of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention under three laser-switched cycles is shown in the figure. Figure 11 The UV-Vis absorption spectra of Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention catalyzing the degradation of methylene blue under different irradiation times are shown. Figure 12 The UV-Vis absorption spectra of Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention continue to catalyze the degradation of methylene blue after the light irradiation is stopped; Figure 13 Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles prepared in Example 1 of this invention were used to detect superoxide anion radicals (•O2) in DMSO. - Electron paramagnetic resonance (EPR) spectrum of ) Figure 14 Electron paramagnetic resonance (EPR) spectra of the Fe-SASP / ART nanoparticles prepared in Example 1 of this invention, with carbon-center free radicals (•CH3), methoxy free radicals (•OCH3), and hydroxyl free radicals (•OH), were detected in distilled water. Figure 15 Fe-SASP / ART nanoparticles prepared in Example 1 of this invention, combined with NIR irradiation, are effective against Propionibacterium acnes (…). P. acnes The antibacterial rate results are shown in the figure. Figure 16 This is a diagram showing the delayed antibacterial effect of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention; Figure 17 This is a DCF fluorescence imaging image of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention after being treated with NIR irradiation with Propionibacterium acnes. Figure 18 The graph shows the cytotoxicity (MTT) results of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention on HaCaT cells at different concentrations. Figure 19 The graph shows the proliferative activity of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention on HaCaT cells under NIR irradiation. Figure 20 The image shows the ELISA results of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention promoting the secretion of epidermal growth factor (EGF) by HaCaT cells under NIR irradiation. Figure 21 The figure shows the inhibitory effect of Fe-SASP / ART nanoparticles prepared in Example 1 of this invention on the expression of pro-inflammatory factors (TNF-α, IL-1β, IL-8) in HaCaT cells stimulated by lipopolysaccharide (LPS). Figure 22 The fluorescence permeation imaging (a) and corresponding fluorescence intensity distribution (b) of the Rhodamine 6G-labeled Fe-SASP / ART nanoparticles prepared in Example 1 of this invention on isolated pig skin are shown. Figure 23 This is a graph showing the change in skin swelling volume in a mouse acne model treated with Fe-SASP / ART nanoparticles combined with NIR irradiation, prepared in Example 1 of this invention. Figure 24 This is a hematoxylin-eosin (H&E) staining image of skin tissue from a mouse model of acne treated with Fe-SASP / ART nanoparticles combined with NIR irradiation, prepared in Example 1 of this invention. Figure 25 This is a flow cytometry analysis of the level of free radicals in the skin tissue of a mouse acne model after treatment with Fe-SASP / ART nanoparticles combined with NIR irradiation prepared in Example 1 of this invention. Figure 26 This is an ELISA image showing the levels of TNF-α and IL-1β in the skin tissue of a mouse acne model after treatment with Fe-SASP / ART nanoparticles combined with NIR irradiation prepared in Example 1 of this invention. Figure 27 Immunohistochemical staining and quantitative analysis of NF-κB p65 in the skin tissue of a mouse acne model after treatment with Fe-SASP / ART nanoparticles prepared in Example 1 of this invention and combined with NIR irradiation. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but this is not intended to limit the scope of protection of the present invention. Example 1

[0027] Preparation of Fe-SASP / ART nanoparticles First, 0.2 mmol of sulfasalazine (SASP) was dissolved in 10 mL of NaOH solution (25 mM). Then, 10 mL of FeCl3 solution (75 mM) was added dropwise to the above solution under stirring for 30 minutes to form Fe-SASP nanoparticles. Simultaneously, 0.1 mmol of artemisinin (ART) was dissolved in 10 mL of anhydrous ethanol and then co-incubated with 0.4 mL of NaOH solution (0.5 M) at 50 °C for 30 minutes for hydrolysis. Subsequently, the treated artemisinin solution was added dropwise to the solution containing the formed Fe-SASP nanoparticles, and the mixture was stirred for 1 hour. Finally, the product was collected by centrifugation (8000 r / min, 10 min, 3 times), washing three times with distilled water, and drying at 60 °C.

[0028] Scanning electron microscope images of the above products ( Figure 2 ) and transmission electron microscope images ( Figure 3 The X-ray diffraction pattern shows that the product has a spherical structure with an average particle size of 80 ± 14 nm. Figure 4 The results showed that Fe-SASP nanoparticles exhibited poor crystallinity (broad and weak diffraction peaks), while Fe-SASP / ART nanoparticles exhibited obvious diffraction peaks similar to pure SASP, indicating that artemisinin, as a structure inducer, transformed the amorphous Fe-SASP precursor into an ordered crystalline framework. Example 2

[0029] Specific surface area and porosity detection of Fe-SASP / ART nanoparticles The sample prepared according to Example 1 was subjected to nitrogen adsorption-desorption analysis. Figure 5 As shown, both Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles exhibit typical type I isothermal adsorption curves. BET surface area analysis results show that the specific surface area of ​​Fe-SASP / ART nanoparticles is 91.2 m². 2 g -1 The total pore volume is 0.68 cm³. 3 g -1 The specific surface area of ​​Fe-SASP nanoparticles is 71.2 m². 2 g -1 The total pore volume is 0.46 cm³.3 g -1 . Example 3

[0030] Fourier transform infrared spectroscopy detection of Fe-SASP / ART nanoparticles The sample prepared according to Example 1 was subjected to Fourier transform infrared spectroscopy analysis. For example... Figure 6 As shown, compared with the FTIR spectrum of SASP, the 1677 cm⁻¹ spectrum attributable to the carboxyl ν (C=O) vibration in Fe-SASP nanoparticles... -1 The characteristic peak shifted to 1593 cm⁻¹ -1 This indicates that the carboxyl group participates in the interaction with Fe. 3+ Coordination. Simultaneously, the 1281 cm⁻¹ segment in SASP, attributed to the ν(CO) stretching vibration. -1 The characteristic peak shifted to 1260 cm⁻¹ in Fe-SASP nanoparticles. -1 The presence of this indicates that the phenolic hydroxyl group also participates in the interaction with Fe. 3+ Coordination. In the FTIR spectrum of Fe-SASP / ART nanoparticles, the peak attributed to the C=O vibration is at 1593 cm⁻¹. -1 The peak at 1281 cm⁻¹ was observed, while the peak attributed to the CO vibration recovered to 1281 cm⁻¹. -1 The presence of this indicates that the phenolic hydroxyl groups in ART and SASP compete with Fe. 3+ Coordination. Furthermore, at 678 cm... -1 A characteristic peak belonging to the Fe-O stretching vibration appeared at this point, which is Fe 3+ Coordination with the ligand oxygen donor atom provided direct spectroscopic evidence. Example 4

[0031] X-ray photoelectron spectroscopy detection of Fe-SASP / ART nanoparticles The sample prepared according to Example 1 was subjected to X-ray photoelectron spectroscopy analysis. For example... Figure 7 As shown, both Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles exhibit O 1s, N 1s, C 1s, S 2p, and Fe 2p peaks in their spectra. High-resolution X-ray photoelectron spectroscopy (XPS) Figure 8 The data shows that Fe 2p 3 / 2 The binding energy shifts positively from 710.96 eV in Fe-SASP nanoparticles to 711.36 eV in Fe-SASP / ART nanoparticles, reflecting a decrease in the electron density around the Fe nucleus and confirming that ART was successfully coordinated to the Fe center in the Fe-SASP matrix. Example 5

[0032] Photothermal properties of Fe-SASP / ART nanoparticles The Fe-SASP / ART nanoparticles prepared according to Example 1 were dispersed in 200 μL of distilled water at concentrations of 0, 100, 200, 300, 400, and 500 μg / mL. The solutions were then exposed to 808 nm laser irradiation (1 W / cm²). 2 (This involves) using a thermal infrared imager to detect temperature changes after different irradiation times. For example... Figure 9 As shown, the temperature of the 500 μg / mL dispersion increased by approximately 14.5 °C after 6 minutes of irradiation. The calculated photothermal conversion efficiency of the Fe-SASP / ART nanoparticles was 42.9%. Furthermore, the Fe-SASP / ART nanoparticles exhibited stable photothermal cycling performance in three consecutive 808 nm laser switching cycles (irradiation was stopped after 6 minutes, the solution was allowed to cool naturally to room temperature, and then irradiation was immediately repeated). Figure 10 This demonstrates that it has good photothermal repeatability. Example 6

[0033] Detection of free radical generation ability of Fe-SASP / ART nanoparticles Methylene blue was used as a free radical indicator. Fe-SASP / ART nanoparticles or Fe-SASP nanoparticles (final concentration 500 μg / mL) prepared as described in Example 1 were mixed with methylene blue (final concentration 10 μg / mL) and subjected to an 808 nm laser (1 W / cm²). 2 Irradiation was performed for different times (15, 30, 45, 60 min). After centrifugation, the supernatant was collected, and its absorbance at 664 nm was measured using a UV-Vis spectrophotometer. Figure 11 As shown, both Fe-SASP nanoparticles and Fe-SASP / ART nanoparticles promoted the degradation of methylene blue under NIR irradiation, and the degradation rate increased with prolonged irradiation time. Under the same irradiation time, Fe-SASP / ART nanoparticles exhibited a higher ability to degrade methylene blue.

[0034] To assess the ability to continuously generate free radicals, Fe-SASP / ART nanoparticles or a mixed solution of Fe-SASP nanoparticles (500 μg / mL) and methylene blue (10 μg / mL) were exposed to NIR irradiation (808 nm, 1 W / cm²). 2The light was applied for 30 minutes, and then left in the dark for another 30 minutes. The results showed that Fe-SASP / ART nanoparticles continued to generate free radicals for up to 30 minutes after the light exposure stopped, resulting in a further increase in the methylene blue degradation rate from 18.3% to 39.9%, while the Fe-SASP nanoparticles only increased from 22.1% to 27.7%. Figure 12 ). Example 7

[0035] Electron paramagnetic resonance detection of Fe-SASP / ART nanoparticles The sample prepared according to Example 1 was mixed with DMPO (spin trapping agent) in DMSO or distilled water, and then subjected to an 808 nm laser (1 W / cm²). 2 Irradiate for 2 minutes, then record the EPR spectrum within 10 minutes. (e.g.) Figure 13 As shown in Figure 14, in DMSO, Fe-SASP nanoparticles were detected after NIR irradiation, corresponding to superoxide anion radicals (•O2). - The characteristic peaks of the Fe-SASP / ART nanoparticles were observed, and the peak intensities of the Fe-SASP / ART nanoparticles were significantly increased. In distilled water, the Fe-SASP / ART nanoparticles exhibited characteristic peaks corresponding to •CH3, •OCH3, and •OH radicals under NIR irradiation, while the Fe-SASP nanoparticles did not show these peaks under the same conditions. Example 8

[0036] In vitro antibacterial activity assay of Fe-SASP / ART nanoparticles The antibacterial effect of Fe-SASP / ART nanoparticles was evaluated using the coating plate method. Propionibacterium acnes (…) was then applied to the nanoparticles. P. acnes (1×10) 7 The bacteria (CFU / mL) were incubated with different samples (200 μg / mL) at 37°C for 4 hours. Then, the bacteria were exposed to an 808 nm laser (1 W / cm²). 2 10 minutes. Dilute the bacterial suspension and spread it on BHI agar plates. Incubate at 37°C for 48 hours, and count the colony-forming units.

[0037] like Figure 15 As shown, Fe-SASP / ART nanoparticles combined with NIR irradiation have the effect on... P. acnes The antibacterial rate reached 69.5% ( Figure 15 ). Example 9

[0038] Delayed-release antibacterial effect test of Fe-SASP / ART nanoparticles To elucidate the time-dependent antibacterial effect of Fe-SASP / ART nanoparticles, an 808 nm laser (1 W / cm²) was used. 2 Bacterial survival was monitored immediately after irradiation and after an additional 4-hour incubation. Figure 16 As shown, the CFU ratio of the Fe-SASP / ART nanoparticle treatment group after light irradiation and subsequent culture to that immediately after light irradiation was 0.337, which was much lower than that of the Fe-SASP nanoparticle group (0.466) and the NIR group alone (0.688), indicating that Fe-SASP / ART nanoparticles have a significant delayed bactericidal effect. Example 10

[0039] Intracellular reactive oxygen species detection of Fe-SASP / ART nanoparticles Intracellular reactive oxygen species (ROS) levels were detected using the DCFH-DA probe. A suspension of *Propionibacterium acnes* (1×10⁻⁶) was prepared. 7 CFU / mL) of Fe-SASP nanoparticles or Fe-SASP / ART nanoparticles were incubated in 24-well plates at 37 °C for 4 hours. DCFH-DA was added and incubation continued for 30 minutes. The bacteria were then washed with PBS and examined under NIR light (808 nm, 1 W / cm²). 2 Irradiate for 10 minutes and observe using an inverted fluorescence microscope. Figure 17 As shown, the group treated with Fe-SASP / ART nanoparticles in combination with NIR irradiation showed the strongest DCF fluorescence signal. Example 11

[0040] Cytotoxicity detection of Fe-SASP / ART nanoparticles The cytotoxicity of Fe-SASP / ART nanoparticles to human immortalized keratinocytes (HaCaT) was evaluated using the MTT assay. HaCaT cells were incubated at 5 × 10⁻⁶ cells / day. 3 Cells were seeded at a density of 1:1 in 96-well plates. After 24 hours of culture, the medium was replaced with fresh medium containing different concentrations of Fe-SASP / ART nanoparticles (20, 50, 100, 150, 200, 300 μg / mL), and cultured for another 24 hours. Then, MTT solution was added and cultured for another 4 hours. After adding DMSO, the absorbance at 490 nm was recorded using a microplate reader.

[0041] like Figure 18As shown, cell viability exceeded 100% within the concentration range of 0-100 μg / mL. Although cell viability gradually decreased above 100 μg / mL, it remained at approximately 83% at 200 μg / mL, indicating that Fe-SASP / ART nanoparticles exhibit low cytotoxicity even at higher concentrations. Notably, under NIR irradiation (the laser was placed 50 cm above the 96-well plate, and the cells were irradiated for 10 min), cell viability reached a peak of 120.9% at 100 μg / mL. Figure 19 Even at 300 μg / mL, it still maintained 92.4%. Example 12

[0042] Epidermal growth factor secretion detection of Fe-SASP / ART nanoparticles The concentration of epidermal growth factor secreted by HaCaT cells was detected by ELISA. HaCaT cells were cultured at a concentration of 5 × 10⁻⁶ cells / cell. 3 Cells were seeded at a density of 200 μg / mL in 96-well plates and cultured for 24 hours. The culture medium was then replaced with fresh medium containing 200 μg / mL Fe-SASP / ART nanoparticles. For the experimental group, cells were first co-incubated with Fe-SASP / ART nanoparticles for 4 hours, followed by laser incubation at 808 nm (1 W / cm²). 2 Irradiate for 10 minutes, then incubate in the dark for 20 hours. Collect the cell supernatant and analyze using an ELISA kit. Figure 20 As shown, Fe-SASP / ART nanoparticles significantly enhanced the secretion of epidermal growth factor under NIR irradiation. Example 13

[0043] Anti-inflammatory activity assay of Fe-SASP / ART nanoparticles The anti-inflammatory effect of Fe-SASP / ART nanoparticles was evaluated by measuring the expression of inflammatory mediators in lipopolysaccharide (LPS)-stimulated HaCaT cells. HaCaT cells were cultured at 5 × 10⁻⁶ cells / cells. 3 Cells were seeded at a density of 1:1 in 96-well plates and cultured for 24 hours. The culture medium was then replaced with fresh medium containing 200 μg / mL Fe-SASP / ART nanoparticles or free SASP molecules. After another 12 hours of culturing, lipopolysaccharide (1 μg / mL) was added and incubated for another 24 hours. The cell culture supernatant was collected, and the levels of TNF-α, IL-1β, and IL-8 were detected using an ELISA kit. Figure 21 As shown, Fe-SASP / ART nanoparticle treatment significantly reduced the expression of pro-inflammatory factors, and this downregulation effect was significantly stronger than that of SASP alone. Example 14

[0044] In vitro skin penetration assay of Fe-SASP / ART nanoparticles The in vitro skin permeability of Fe-SASP / ART nanoparticles was evaluated using pig skin. Fresh pig skin was washed with PBS and cut into 1.5 × 1.5 cm pieces. 2 Small pieces of Rhodamine 6G-labeled Fe-SASP / ART nanoparticles (200 μg / mL) aqueous solution were topically applied to pig skin and incubated in a humidified chamber at 32°C for 8 hours. The samples were then washed three times with PBS and dried. Skin samples were fixed with 4% paraformaldehyde, frozen, sectioned, and observed under a fluorescence microscope. Figure 22 As shown, free rhodamine 6G is mainly confined to the stratum corneum, while Fe-SASP / ART nanoparticles effectively penetrate deep into the skin and accumulate significantly in hair follicles. The penetration depth of Fe-SASP / ART nanoparticles can reach 600 μm. Example 15

[0045] In vivo anti-acne effects of Fe-SASP / ART nanoparticles The therapeutic effect of Fe-SASP / ART nanoparticles was evaluated in acne-prone mice. The effect was assessed by intradermal injection of Propionibacterium acnes (1×10⁻⁶). 9 An acne model was established on the backs of Balb / c nude mice by injecting CFU / mL (0.1 mL) for 7 consecutive days. The successfully modeled mice were randomly divided into 5 groups (n=6): (1) emulsion treatment group (control group), (2) Fe-SASP / ART group, (3) emulsion + NIR group, (4) Fe-SASP / ART + NIR group, and (5) Fe-SASP + NIR group. Fe-SASP / ART nanoparticles or Fe-SASP nanoparticles were dispersed in a mixed emulsion (5 mg / mL) and applied to the inflamed area at a dose of 125 mg / kg. For the NIR treatment group, the sample was treated with an 808 nm laser (1 W / cm²) after application. 2 Irradiate the inflamed area for 5 minutes. This treatment is performed only once on day 0. During the treatment period, the length and width of the swollen area are measured daily with calipers, and the acne swelling volume is calculated.

[0046] like Figure 23 As shown, the Fe-SASP / ART nanoparticle combined with NIR irradiation group showed almost complete regression of acne cysts and smooth, flat skin surface on day 5. In contrast, the Fe-SASP / ART nanoparticle alone group (19.88 mm) showed significant improvement. 3 ), NIR alone (16.17 mm) 3 ) and Fe-SASP nanoparticles combined with NIR group (1.97 mm) 3 There are still residual skin protrusions. Example 16

[0047] Histological analysis after Fe-SASP / ART nanoparticle therapy Skin tissues from mice in different treatment groups in Example 15 were collected, fixed in 4% formalin solution for 48 hours, then dehydrated with graded ethanol and xylene, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Figure 24 As shown, compared with normal mice, the control group mice exhibited significant skin remodeling, characterized by marked acanthosis, hyperkeratosis, and epidermoid cysts within the thickened epidermis. Compared with the control group, the Fe-SASP / ART group and the Fe-SASP+NIR group showed improved acanthosis and hyperkeratosis, but these conditions still persisted. The Fe-SASP / ART nanoparticle combined with NIR irradiation group showed a more ordered skin structure, with no detectable epidermoid cysts, and the epidermal thickness was comparable to that of normal mouse skin. Example 17

[0048] In vivo free radical level detection of Fe-SASP / ART nanoparticles Immediately collect mouse skin tissue after treatment in Example 15, wash with cold PBS, scrape off the fat, cut into small pieces, and disperse in an enzymatic digest containing collagenase II and DNase I. After incubation at 37 °C for 60 minutes, filter the mixture through a 100 μm nylon mesh to remove large fragments. The resulting cell suspension is mixed with ACK lysis buffer, incubated at room temperature for 3 minutes, washed with PBS, stained with DCFH-DA, and analyzed by flow cytometry. Figure 25 As shown, the group with Fe-SASP / ART nanoparticles combined with NIR irradiation had the highest fluorescence intensity, which was about twice that of the emulsion treatment group. Example 18

[0049] In vivo anti-inflammatory activity assay of Fe-SASP / ART nanoparticles Skin tissue from mice in Example 15 was collected, washed with cold PBS, fat was scraped off, homogenized by low-temperature grinding, and then centrifuged at 3000 rpm for 15 minutes at 4°C. The supernatant was collected, and TNF-α and IL-1β levels were detected using an ELISA kit. Figure 26 As shown, the Fe-SASP / ART nanoparticles combined with NIR irradiation group had the strongest downregulation effect on TNF-α and IL-1β in skin tissue. Example 19

[0050] Immunohistochemical analysis of Fe-SASP / ART nanoparticles Skin specimens collected in Example 15 were fixed in 4% formalin solution for 48 hours, then dehydrated with a gradient of ethanol and xylene, embedded in paraffin, and sectioned. The paraffin sections were incubated with 0.01 M Tris-EDTA solution for antigen retrieval, and then incubated with mouse anti-NF-κB p65 antibody to assess the expression of NF-κB p65 protein in the skin. Figure 27 As shown, the Fe-SASP / ART nanoparticles combined with NIR irradiation reduced NF-κB expression to 9.7% in the emulsion-treated group.

[0051] The above embodiments are only used to illustrate the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention within the scope of knowledge possessed by those skilled in the art should be considered within the scope of protection of this application.

[0052] The working principle of the Fe-SASP / ART nanoparticles prepared in this invention for treating acne is as follows: Figure 1 As shown, by Figure 1 It is known that the Fe-SASP / ART nanoparticles prepared in this invention, through the use of artemisinin as a structure inducer and co-ligand, endow the nanoparticles with photothermal conversion properties, photodynamic activity, oxygen-independent carbon center free radical generation ability, and self-sustaining Fe... 3+ / Fe 2+ It possesses the ability to generate delayed free radicals mediated by redox cycles, anti-inflammatory activity, and the ability to promote keratinocyte proliferation, thereby treating acne through multiple mechanisms of photothermal / photodynamic synergistic antibacterial, anti-inflammatory, and repair-promoting effects.

[0053] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles, characterized in that, The steps include the following: (1) Dissolve sulfasalazine in an alkaline medium and add Fe while stirring. 3+ Stir for 20-40 minutes to obtain an amorphous iron-sulfasalazine precursor; wherein, Fe 3+ The molar ratio of sulfasalazine to sulfasalazine is (0.5~1):(0.1~1). (2) Dissolve artemisinin in ethanol, add alkaline solution, and hydrolyze at 40~80℃ for 0.5~4 hours; (3) Add the hydrolyzed artemisinin obtained in step (2) to the amorphous iron-sulfasalazine precursor obtained in step (1), stir for 0.5 to 2 hours, and obtain iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles by centrifugation, washing and drying; wherein the molar ratio of iron-sulfasalazine nanoparticles to artemisinin is (1 to 2):

1.

2. The preparation method according to claim 1, characterized in that, In steps (1) and (2), the alkaline medium and alkaline solution are selected from at least one of NaOH solution, KOH solution and Na2CO3 solution. The concentration of the alkaline medium is 20~30mM, the concentration of the alkaline solution is 0.1~1M, the concentration of sulfasalazine in the alkaline medium is 0.01~0.03M, and the molar ratio of artemisinin to the alkali in the alkaline solution is 1:(1~3).

3. The preparation method according to claim 1, characterized in that, In step (1), the Fe 3+ It is derived from FeCl3 solution, with a concentration of 50~100 mM.

4. Iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles prepared by any one of the preparation methods described in claims 1 to 3.

5. The iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles according to claim 4, characterized in that, The nanoparticles have a spherical structure, an average particle size of 50–150 nm, and a specific surface area of ​​50–200 m². 2 g -1 The total pore volume is 0.2~1.5 cm³. 3 g -1 .

6. The iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles according to claim 4, characterized in that, The nanoparticles simultaneously generate photothermal and photodynamic effects under near-infrared light irradiation via a ligand-metal charge transfer mechanism; the nanoparticles generate •O2 under near-infrared light irradiation. - •CH3, •OCH3, •OH, wherein the generation of •CH3, •OCH3, •OH free radicals is independent of oxygen; the nanoparticles, after near-infrared light irradiation ceases, achieve self-sustaining Fe 3+ / Fe 2+ The redox cycle continuously generates free radicals for a period of 10 to 60 minutes.

7. The application of the iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles according to claim 4 in the preparation of acne treatment drugs, characterized in that, The nanoparticles synergistically treat acne through photothermal therapy, photodynamic therapy, iron-activated artemisinin-mediated oxygen-independent free radical generation, self-sustaining redox cycle-mediated delayed sterilization, anti-inflammation, and promotion of keratinocyte proliferation.

8. The application according to claim 7, characterized in that, The nanoparticles were subjected to near-infrared light irradiation via Fe... 2+ Catalytic peroxide bridge cleavage within artemisinin generates carbon-centered free radicals, achieving sterilization under anaerobic conditions; the nanoparticles are self-sustaining Fe... 3+ / Fe 2+ The redox cycle continuously generates free radicals after near-infrared light irradiation ceases, achieving a delayed bactericidal effect. The nanoparticles, through the inherent anti-inflammatory activity of sulfasalazine, inhibit the NF-κB pathway and the expression of TNF-α and IL-1β, thus alleviating the inflammatory response. The nanoparticles promote keratinocyte proliferation through a toxic stimulant effect, achieving a cell viability of 100-150%, and promote the secretion of epidermal growth factor, accelerating tissue repair. The nanoparticles can be targeted and delivered to hair follicles after transdermal administration.

9. The use of the iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles according to claim 4 in the preparation of anti-inflammatory drugs or antioxidant drugs.

10. The use of the iron-sulfasalazine / artemisinin ternary coordination polymer nanoparticles according to claim 4 in the preparation of antibacterial drugs, wherein the antibacterial drugs are effective against Propionibacterium acnes (…). Propionibacterium acnes It has a killing effect.

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