A biomimetic nanoparticle and a preparation method and application thereof

Abstract

The application relates to the technical field of medicines, in particular to a kind of biomimetic nanoparticles and preparation method and application thereof.The biomimetic nanoparticles are obtained by coating drug-loaded nanoparticles with cell membrane;wherein the drug-loaded nanoparticles are prepared by organic photo-functional molecules, anti-inflammatory drugs and surfactants;the fluorescence absorption peak and fluorescence emission peak of the organic photo-functional molecules are at 780nm-2526nm;the mass concentration ratio of the organic photo-functional molecules to the anti-inflammatory drugs is 1:1-25;the mass concentration ratio of the organic photo-functional molecules to the surfactants is 1:3-15, the biomimetic nanoparticles have improved inflammation targeting, improve drug utilization, and realize near-infrared fluorescence imaging of ulcerative colitis lesion area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medicine, in particular to a kind of biomimetic nanoparticles and its preparation method and application. BACKGROUND

[0002] In recent years, ulcerative colitis has become a high incidence of chronic intestinal inflammatory disease after irritable bowel syndrome, which is abbreviated as UC. The imbalance of human intestinal immune homeostasis is the core pathogenesis of UC, mainly manifested as destruction of intestinal mucosal barrier function, abnormal immune cell infiltration and excessive release of pro-inflammatory factors. Due to genetic susceptibility, intestinal flora imbalance or environmental factors induced immune disorder, the balance between intestinal mucosal defense system and immune attack is broken, leading to persistent inflammatory response of colonic mucosa. The pathological progression of UC is closely related to the impaired mucosal repair capacity, and repeated inflammation can cause serious complications, including colonic fibrosis, toxic megacolon and even colorectal cancer.

[0003] Current clinical treatment drugs are mainly divided into four categories: (1) mucosal protective anti-inflammatory drugs: such as 5-aminosalicylic acid and its prodrugs, such as sulfasalazine, which can reduce local inflammation by inhibiting prostaglandin synthesis and neutrophil chemotaxis; (2) immunomodulators: such as glucocorticoids and azathioprine, which can control acute attack by broad-spectrum inhibition of immune cell activity, glucocorticoids such as prednisone; (3) biological target preparations: such as anti-TNF-α monoclonal antibodies and integrin inhibitors, which specifically block key inflammatory pathways, anti-TNF-α monoclonal antibodies such as infliximab, and integrin inhibitors such as vedolizumab; (4) new small molecule drugs: such as JAK inhibitors, which exert anti-inflammatory effects by regulating intracellular signal transduction, JAK inhibitors such as tofacitinib. However, the existing treatment drugs have low lesion accumulation rate and low drug utilization rate due to systemic distribution. SUMMARY

[0004] To solve the above problems, the present application provides a kind of biomimetic nanoparticles and its preparation method and application.

[0005] A kind of biomimetic nanoparticles, using cell membrane to coat drug-loaded nanoparticles is obtained;

[0006] Wherein, the drug-loaded nanoparticles are prepared by organic light functional molecules, anti-inflammatory drugs and surfactants;The fluorescence absorption peak and fluorescence emission peak of the organic light functional molecules are at 780nm-2526nm;The mass concentration ratio of the organic light functional molecules to the anti-inflammatory drugs is 1:1~25;The mass concentration ratio of the organic light functional molecules to the surfactants is 1:3~15.

[0007] A kind of preparation method of biomimetic nanoparticles, comprising the following steps:

[0008] Mixing the organic photo-functional molecule, the anti-inflammatory drug and the surfactant, dialyzing in a dialysis bag with a molecular weight cut-off of 3500 da, and then centrifuging using an ultrafiltration tube with a molecular weight cut-off of 5-10 times of the anti-inflammatory drug to obtain drug-loaded nanoparticles;

[0009] Mixing the cell membrane and the drug-loaded nanoparticles at a weight ratio of 1:9-11, and reacting for 25-35 min to achieve coating of the drug-loaded nanoparticles by the cell membrane, thereby obtaining the biomimetic nanoparticles.

[0010] Preferably, the organic photo-functional molecule is any one of a near-infrared conjugated polymer, a near-infrared conjugated oligomer, an aggregation-induced emission molecule and a near-infrared small molecule fluorescent probe.

[0011] Preferably, the near-infrared conjugated oligomer has the following structural formula:

[0012] .

[0013] Preferably, the anti-inflammatory drug is any one of an aminosalicylate drug and a glucocorticoid drug.

[0014] Preferably, the aminosalicylate drug is any one of sulfasalazine, mesalazine, olsalazine and balsalazide.

[0015] The glucocorticoid drug is any one of prednisone, budesonide, hydrocortisone and dexamethasone.

[0016] Preferably, the surfactant is a phospholipid molecule or a derivative of the phospholipid molecule.

[0017] The phospholipid molecule is at least one of dipalmitoyl phosphatidylcholine, distearoyl phosphatidylcholine, dioleoyl phosphatidylcholine, dimyristoyl phosphatidylcholine, distearoyl phosphatidylethanolamine, dioleoyl phosphatidylethanolamine and (1,2-dioleoyloxypropyl)trimethylammonium chloride.

[0018] The derivative of the phospholipid molecule is at least one of distearoyl phosphatidylethanolamine-polyethylene glycol, dioleoyl phosphatidylethanolamine-polyethylene glycol, dipalmitoyl phosphatidylcholine-polyethylene glycol, distearoyl phosphatidylethanolamine-amino polyethylene glycol, dioleoyl phosphatidylethanolamine-amino polyethylene glycol, dipalmitoyl phosphatidylcholine-amino polyethylene glycol, distearoyl phosphatidylethanolamine-carboxyl polyethylene glycol, dioleoyl phosphatidylethanolamine-carboxyl polyethylene glycol and dipalmitoyl phosphatidylcholine-carboxyl polyethylene glycol.

[0019] Preferably, the cell membrane is any one of a blood cell membrane, a stem cell membrane, an immune cell membrane and an intestinal cell membrane.

[0020] Preferably, the blood cell membrane is any one of a red blood cell membrane, a white blood cell membrane and a platelet membrane;

[0021] The stem cell membrane is any one of an embryonic stem cell membrane, an embryonic germ cell membrane, a mesenchymal stem cell membrane, a hematopoietic stem cell membrane, an epidermal stem cell membrane, an intestinal stem cell membrane, an umbilical cord blood stem cell membrane, a placental / amniotic membrane stem cell membrane and an artificially induced pluripotent stem cell membrane;

[0022] The immune cell membrane is any one of a macrophage membrane, a neutrophil membrane, an NK cell membrane, a dendritic cell membrane, a T cell membrane and a B cell membrane;

[0023] The intestinal cell membrane is any one of a goblet cell membrane, a Paneth cell membrane, an intestinal endocrine cell membrane and a Cajal interstitial cell membrane.

[0024] The application of the biomimetic nanoparticle in the preparation of a drug or a light-responsive drug for treating ulcerative colitis.

[0025] The application of the biomimetic nanoparticle in the preparation of a product for regulating macrophage polarization or a light-responsive product.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] The application provides a biomimetic nanoparticle, the cell membrane coated in the biomimetic nanoparticle improves inflammation targeting, improves the drug utilization rate in the drug-loaded nanoparticle, meanwhile, the organic light functional molecule in the drug-loaded nanoparticle realizes near-infrared fluorescence imaging on a lesion area of ulcerative colitis, and under the assistance of the imaging function, the biomimetic nanoparticle can realize double regulation of an immune microenvironment by precise light treatment on the lesion area.

[0028] The biomimetic nanoparticle is used for imaging and treatment integration of ulcerative colitis, and the precise treatment effect on ulcerative colitis is effectively improved.

[0029] The application not only provides a new method for treating ulcerative colitis, but also provides a new idea and a new method for imaging and treatment integration and double-mode regulation of an immune microenvironment by a drug and a thermal effect for diagnosing and treating other diseases. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The molecular formula of the organic light functional molecule TPA-PT and TPDB-Me involved in Example 1 of the application.

[0031] Figure 2 The preparation schematic diagram of the biomimetic nanoparticle CONPD-M in Example 1 of the application.

[0032] Figure 3 Spectrogram of nanoparticles CONP, CONPD, CONPD-M in Example 1 of the present application, wherein A is absorption spectrum, B is fluorescence spectrum.

[0033] Figure 4 Fluorescence imaging of HIEC-6 cell uptake of biomimetic nanoparticles in LPS-induced inflammatory environment.

[0034] Figure 5 Flow cytometry analysis results of marker levels of RAW264.7 cells under different experimental conditions, wherein A is CD86, B is iNOS, and C is CD206.

[0035] Figure 6 In vivo near-infrared fluorescence imaging and corresponding ex vivo gastrointestinal system near-infrared fluorescence imaging of normal Balb / c mice and DSS-modeled Balb / c mice after injection of CONP and CONP-M nanoparticles for 8h.

[0036] Figure 7 Thermal imaging of DSS-modeled Balb / c mice after injection of nanoparticles CONP-M for 8h under 808nm laser irradiation, as a function of irradiation time.

[0037] Figure 8 Ex vivo colon pictures of Balb / c mice under different experimental conditions. DETAILED DESCRIPTION

[0038] The specific embodiments of the present application are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. The experimental methods described in the embodiments of the present application are conventional methods unless otherwise specified.

[0039] The present application provides a kind of biomimetic nanoparticles for imaging and treatment of ulcerative colitis integration, using cell membrane to be coated drug-loaded nanoparticles, obtain biomimetic nanoparticles, wherein drug-loaded nanoparticles are prepared by organic light functional molecule, anti-inflammatory drug and surfactant, the fluorescence absorption peak and fluorescence emission peak of the organic light functional molecule are at 780nm~2526nm;The mass concentration ratio of the organic light functional molecule and the anti-inflammatory drug is 1:1~25;The mass concentration ratio of the organic light functional molecule and surfactant is 1:3~15.

[0040] With organic light functional molecule as TPDB-Me, anti-inflammatory drug as dexamethasone, and surfactant as DSPE-PEG 2000 To illustrate the preparation of biomimetic nanoparticles.

[0041] As shown in Figure 1 , first of all, the molecular design strategy of donor-acceptor structure is used to synthesize TPA-PT, and on this basis, the introduction of electron-deficient boron group on the conjugated structure reduces the LUMO energy level of the molecule, thereby synthesizing a near-infrared conjugated oligomer TPDB-Me.

[0042] As shown in Figure 2 , TBDB-Me and dexamethasone are prepared into drug-loaded nanoparticles CONPD by micro-precipitation under the dispersion of DSPE-PEG 2000 . Subsequently, the surface of CONPD is coated with macrophage cell membrane to prepare a biomimetic nanoparticle, wherein the abbreviation of dexamethasone is DEX.

[0043] The biomimetic nanoparticle of the present application targets the ulcerative colitis lesion area through the macrophage cell membrane on the surface. By utilizing the near-infrared fluorescence property of the biomimetic nanoparticle, near-infrared fluorescence in vivo imaging of the ulcerative colitis lesion area can be realized. With the aid of this imaging function, by utilizing the photothermal conversion function of the biomimetic nanoparticle, precise warm treatment of the ulcerative colitis lesion area is carried out. Under the dual action of anti-inflammatory drugs and photothermal effect, the immune microenvironment of the ulcerative colitis lesion area is effectively regulated, especially the M2 type polarization regulation of macrophages, thereby effectively improving the precise treatment effect of ulcerative colitis, realizing the integration of imaging treatment. The problems of low drug utilization rate and side effects existing in the current single drug treatment are solved. The system not only provides a new method for the treatment of ulcerative colitis, but also provides a new idea and method for the integration of imaging and treatment and the dual-mode regulation of immune microenvironment by drugs and heat effect for the diagnosis and treatment of other diseases.

[0044] The derivative of the phospholipid molecule involved in the present application is shown in Table 1.

[0045] Table 1 Derivative of phospholipid molecule

[0046]

[0047] Example 1

[0048] 1. Synthesis of near-infrared conjugated oligomer, the synthesized near-infrared conjugated oligomer is denoted as TPDB-Me

[0049] Under the nitrogen environment, 2.106 g of 4-bromo-4',4''-dimethyltriphenylamine was dissolved in 10 mL of anhydrous tetrahydrofuran. 2.5 mL of n-BuLi n-hexane solution was added dropwise to the reaction solution under low-temperature reaction conditions, and the molar concentration of n-BuLi in the n-BuLi n-hexane solution was 2.4 M. The reaction was carried out for 1.5 h to obtain a reaction solution. 1.022 g of ZnCl2 was dissolved in 10 mL of anhydrous THF and transferred to the above reaction solution for continuous reaction for 2 h to obtain a reaction mixture. The reaction mixture was transferred to a Schlenk tube containing 589.9 mg of 4,7-dibromo-[1,2,5]thiadiazolo[3,4-c]pyridine and 116 mg of Pd(PPh3)4, and the temperature was raised to 70°C for reaction for 24 h. After the reaction was completed, the temperature was cooled to room temperature, quenched with saturated aqueous ammonium chloride solution, extracted with ethyl acetate, and the organic phase was collected and dried over anhydrous Na2SO4. Then, the solvent was concentrated on a rotary evaporator, and the concentrated product was purified by silica gel column chromatography. The eluent used for the purification was petroleum ether and dichloromethane at a volume ratio of 9:1. Finally, compound TPA-PT was obtained in a mass of 1.017 g with a yield of 52%, and the structure of TPA-PT is shown in Figure 1 .

[0050] Under the nitrogen environment, 2.106 g of 4-bromo-4',4''-dimethyltriphenylamine was dissolved in 10 mL of anhydrous tetrahydrofuran. 2.5 mL of n-BuLi n-hexane solution was added dropwise to the reaction solution under low-temperature reaction conditions, and the molar concentration of n-BuLi in the n-BuLi n-hexane solution was 2.4 M. The reaction was carried out for 1.5 h to obtain a reaction solution. 1.022 g of ZnCl2 was dissolved in 10 mL of anhydrous THF and transferred to the above reaction solution for continuous reaction for 2 h to obtain a reaction mixture. The reaction mixture was transferred to a Schlenk tube containing 589.9 mg of 4,7-dibromo-[1,2,5]thiadiazolo[3,4-c]pyridine and 116 mg of Pd(PPh3)4, and the temperature was raised to 70°C for reaction for 24 h. After the reaction was completed, the temperature was cooled to room temperature, quenched with saturated aqueous ammonium chloride solution, extracted with ethyl acetate, and the organic phase was collected and dried over anhydrous Na2SO4. Then, the solvent was concentrated on a rotary evaporator, and the concentrated product was purified by silica gel column chromatography. The eluent used for the purification was petroleum ether and dichloromethane at a volume ratio of 9:1. Finally, compound TPA-PT was obtained in a mass of 1.017 g with a yield of 52%, and the structure of TPA-PT is shown in Figure 1 .

[0051] 2, preparation of cell membrane-coated biomimetic nanoparticles, which are denoted as CONPD-M

[0052] The preparation schematic diagram is as shown in Figure 2DEX, 2 mg, was dissolved in 0.1 mL of DMSO to prepare a solution with a concentration of 20 mg / mL, 10 mg of DSPE-PEG 2000 , 1 mg of TPDB-Me molecules was dissolved in 1 mL of tetrahydrofuran to prepare a solution with a concentration of 1 mg / mL. After mixing the above solutions, 20 mL of pure water was added, and the probe was ultrasonicated for 5 min, with a power setting of 40% of the total power of 150 W, and an ultrasonic opening time of 3 s and a closing time of 2 s. After ultrasonication, the sample solution was transferred to a dialysis bag with a molecular weight cutoff of 3500 da, and dialyzed in pure water for 24 h, with water changes 4 times, to remove tetrahydrofuran. Then, it was centrifuged 4 times using an ultrafiltration tube with a molecular weight cutoff of 3000 da, and the solution was concentrated to a volume of about 0.5 mL, to obtain drug-loaded nanoparticles, which are referred to as CONPD.

[0053] The macrophage cell membrane was extracted. The RAW264.7 cell suspension was collected in a centrifuge tube, after centrifugation, the supernatant was discarded, and PBS was added and vortexed, then centrifuged again, and the cells were washed twice in this way. 5 times the volume of the cell precipitate of sterilized water was added to the centrifuge tube, and the sterilized water was prepared by adding PMSF at a ratio of sterilized water:PMSF = 100:1 at 4°C, vortexing to mix, and then placing in a 4°C refrigerator overnight. The cell suspension was mixed and ultrasonicated in an ice bath for 5 min, with a power setting of 100% of the total power of 150 W, and an ultrasonic opening time of 2 s and a closing time of 2 s. The broken cell membrane solution was centrifuged at 4°C and 3200 g for 15 min, the precipitate was discarded, and the supernatant was collected and centrifuged again at 4°C and 15000 g for 30 min, the supernatant was discarded, and the precipitate was collected and dispersed in an appropriate amount of pre-cooled sterilized water and stored in a -80°C refrigerator for later use.

[0054] CONPD and purified macrophage membranes were mixed together at a weight ratio of 1:10, and water bath ultrasonication was performed for 30 min. After ultrasonication, the biomimetic nanoparticles were obtained, and the biomimetic nanoparticles were repeatedly extruded through a polycarbonate membrane with a pore size of 400 nm for 70 times to make the biomimetic nanoparticles more uniform, and were recorded as CONPD-M and stored in a 4°C refrigerator for later use.

[0055] 3. Preparation of comparative compounds

[0056] The comparative compounds were CONP, CONPCY5, CONP-M, and CONPCY5-M.

[0057] In order to facilitate comparison in the experiment, similar schemes were used to prepare nanoparticles for comparison, i.e. nanoparticles without the addition of DEX, which were recorded as CONP.

[0058] The CONP was labeled, i.e. 0.2 mg / mL of DSPE-CY5 was added to a mixed solution of 1 mg / mL of TPDB-Me solution and 5 mg / mL of DSPE-PEG2000 solution to obtain DSPE-CY5-labeled CONP, which was denoted as CONPCY5.

[0059] The CONP was subjected to macrophage membrane coating to obtain cell membrane-coated CONP, which was denoted as CONP-M.

[0060] The CONPCY5 was subjected to macrophage membrane coating to obtain cell membrane-coated CONPCY5, which was denoted as CONPCY5-M.

[0061] Effect verification

[0062] 1. Spectral test

[0063] The absorption spectrum and fluorescence spectrum of the nanoparticles CONP, CONPD and CONPD-M were tested respectively, and the spectrum is shown in Figure 3 The absorption peak of the three kinds of nanoparticles is near 800 nm, and the fluorescence emission peak is near 1100 nm. The results show that the nanoparticles meet the optical properties of near-infrared absorption and fluorescence emission, have tissue penetration, and can be applied to the in vivo imaging of ulcerative colitis.

[0064] 2. In vitro nanoparticle uptake test

[0065] The nanoparticles CONPCY5 and CONPCY5-M were respectively reacted with normal HIEC-6 cells and LPS-induced HIEC-6 cells under culture conditions for 6 h, and then stained with DAPI at 37°C for 20 min. After removing the staining solution and washing twice with PBS, fluorescence imaging was performed by confocal laser scanning microscopy. Among them, DAPI was excited at 405 nm, and the image was collected under the fluorescence receiving channel of 410 nm-600 nm. CY5 was excited at 638 nm, and the image was collected under the fluorescence receiving channel of 645 nm-750 nm. The imaging results are shown in Figure 4 CONPCY5-M exhibited significantly improved CY5 channel fluorescence in LPS-induced HIEC-6 cells, indicating that CONPCY5-M has a higher cell uptake rate under this condition. The results prove that CONPCY5-M has significantly improved targeting to cells in an inflammatory environment at the in vitro experimental level.

[0066] 3. Nanoparticle regulation of macrophage polarization

[0067] RAW 264.7 cells were seeded in 96-well plates and incubated overnight, then divided into control group, LPS treatment group, IL-4 treatment group, DEX treatment group, CONPD treatment group, CONPD-M treatment group, and CONP+NIR treatment group and CONPD-M+NIR treatment group.

[0068] The control group was replaced with blank fresh culture solution in the 96-well plate

[0069] The LPS treatment group was replaced with fresh culture solution containing 1 μg / mL LPS in the 96-well plate.

[0070] The IL-4 treatment group was replaced with fresh culture solution containing 20 ng / mL IL-4 in the 96-well plate. The DEX treatment group was replaced with fresh culture solution containing 1 μM DEX in the 96-well plate.

[0071] The CONPD treatment group was replaced with fresh culture solution containing CONPD in the 96-well plate, the effective concentration of TPDB-Me in CONPD was 20 μM, and the effective concentration of DEX was 1 μM.

[0072] The CONPD-M treatment group was replaced with fresh culture solution containing CONPD-M in the 96-well plate, the effective concentration of TPDB-Me in CONPD-M was 20 μM, and the effective concentration of DEX was 1 μM.

[0073] The CONP+NIR treatment group was replaced with fresh culture solution containing CONP in the 96-well plate, then irradiated at 0.8 W / cm 2 for 10 min with an 808 nm laser, and the temperature change was recorded with an infrared thermal imager, and the liquid temperature in the plate was maintained at about 42°C by adjusting the laser power appropriately, the effective concentration of TPDB-Me in CONP was 20 μM.

[0074] The CONPD-M+NIR treatment group was replaced with fresh culture solution containing CONPD-M in the 96-well plate, then irradiated at 0.8 W / cm 2 for 10 min with an 808 nm laser, and the temperature change was recorded with an infrared thermal imager, and the liquid temperature in the plate was maintained at about 42°C by adjusting the laser power appropriately, the effective concentration of TPDB-Me in CONPD-M was 20 μM, and the effective concentration of DEX was 1 μM.

[0075] After incubation for 24 hours, cells were washed twice with PBS, fixed with 4% paraformaldehyde for 30 minutes, washed twice more with PBS, permeabilized with 1% Triton for 10 minutes, blocked with 2% BSA for 1 hour, and then incubated overnight at 4°C with CD86 antibody, iNOS antibody, and CD206 antibody, respectively. Cells were washed twice with PBS, incubated with FITC-labeled goat anti-rabbit IgG (H&L) at 37°C in the dark for 1 hour, washed twice more with PBS, and the cell suspension was collected for flow cytometry analysis. The flow cytometer was set to the FITC-A channel. CD86 and iNOS are M1 polarization markers for RAW 264.7 cells, representing pro-inflammatory activity. CD206 is an M2 polarization marker, representing anti-inflammatory activity.

[0076] like Figure 5 As shown, compared to the control group, the LPS treatment group exhibited significantly elevated CD86 and iNOS levels, while other treatment groups showed no significant difference from the control group or decreased CD86 and iNOS levels, and significantly elevated CD206 levels. Among them, the CONPD-M+NIR treatment group showed the most significantly decreased CD86 and iNOS levels and increased CD206 levels, indicating that CONPD-M+NIR has a significant regulatory function in inducing macrophage M2 polarization. Notably, the non-light-exposed CONPD-M treatment group and the non-drug CONPD+NIR treatment group also showed the ability to regulate macrophage M2 polarization, but CONPD-M+NIR showed a more effective regulatory capacity compared to both, indicating that the combined effects of drug action and thermotherapy have a better anti-inflammatory effect than either alone.

[0077] 4. Near-infrared fluorescence in vivo imaging of nanoparticles

[0078] Balb / c mice were randomly divided into normal group and DSS modeling group. The normal group was given distilled water every day, and the modeling group was given 250 μL of 3% DSS by gavage every day for 7 consecutive days. After the modeling was completed, the normal group and the DSS modeling group were randomly divided into two groups. After the mice were depilated and fixed in a fixer, 200 μL of CONP and CONP-M solution was injected into the mice through the tail vein. After 8 hours of injection of CONP solution and CONP-M solution into the mice, the mice were anesthetized with isoflurane by gas machine, and then placed in a near-infrared II zone fluorescence live imaging system. The live near-infrared fluorescence imaging of the mice was taken under the excitation of an 808 nm laser. After the live near-infrared fluorescence imaging was taken, the mice were sacrificed, and the complete gastrointestinal tract tissue of the mice was taken out. The fluorescence imaging of the gastrointestinal tract tissue of the mice was taken by a near-infrared II zone live imaging instrument. Imaging parameters: excitation wavelength: 808 nm; laser power: 15 W; exposure time: 500 ms; filter: 1000 nm.

[0079] As shown in Figure 6 , CONP-M showed stronger fluorescence signals in the live imaging and ex vivo imaging of the gastrointestinal system of the DSS modeling group than other groups, indicating that nanoparticles coated with macrophage cell membranes have better targeting accumulation for ulcerative colitis. At the same time, the fluorescence signal of CONP-M in the modeling group was significantly higher than that in the non-modeling group, indicating that it has image diagnosis function.

[0080] 5. In vivo photothermal effect of nanoparticles

[0081] After 8 hours of injection of CONP-D-M into the DSS modeling group of Balb / c mice through the tail vein, the lower abdominal intestinal tract of the mice was irradiated with an 808 nm laser at 0.6 W / cm 2 for 10 minutes. Referring to the in vivo fluorescence imaging image, the thermal imaging of the mice at different irradiation times was recorded by an infrared thermal imager. As shown in Figure 7 , with the extension of irradiation time, the lower abdominal intestinal tract of the mice was heated from about 25°C at 0 min to about 45°C after 2 min irradiation, and maintained at this temperature under 10 min irradiation. The results show that CONP-D-M has good photothermal conversion ability and can realize the heating of the in vivo internal tissue under irradiation, which is beneficial to the photothermal treatment of the in vivo internal tissue.

[0082] 6. Animal experiment evaluation of nanoparticles for treating ulcerative colitis

[0083] The DSS modelled ulcerative colitis mice were randomly divided into normal saline group, free DEX group, CONPD-M group and CONPD-M+NIR group, 6 mice in each group. Then, from the first day, the mice were administered once every other day, i.e. the first day, the third day and the fifth day, through the tail vein, with an equal amount of DEX 0.25mg / kg, and for the CONPD-M+NIR group, 8h after the mice in each group were injected with the drug through the tail vein, an 808nm laser was used at 0.6W / cm 2 The mice were treated for 10min with light on the lower abdominal intestinal tract. On the sixth day, the mice were sacrificed, and the mouse ex vivo heart, liver, spleen, lung, kidney and colon tissues were collected, the colon length of the mice in each group was measured, and H&E staining was performed on each tissue for evaluation of in vivo biocompatibility and colon tissue morphology. AB / PAS staining was performed on the colon tissue. During the treatment, the body weight change of the mice in each group was also monitored every day, and the feces of the mice were collected to measure fecal occult blood, and the fecal occult blood index was combined with the body weight change and fecal characteristics to calculate the disease activity index score, which is abbreviated as DAI.

[0084] As shown in Figure 8 CONPD-M+NIR group exhibited a similar colon length to the healthy control group, while the colon length was significantly increased compared to the other treatment groups. The results showed that CONPD-M, under 808 laser irradiation, had a significantly improved therapeutic effect of the combined drug and thermal treatment compared to traditional DEX drug treatment.

[0085] The present application designs to prepare a kind of for ulcerative colitis imaging and treatment integration bionic nanoparticles, the bionic nanoparticles have enhanced target accumulation to ulcerative colitis lesion area, and the bionic nanoparticles have the function of in vivo near infrared fluorescence imaging simultaneously, can realize the fluorescence imaging of ulcerative colitis lesion area assisted more accurate treatment.Under the guidance of this imaging function, the bionic nanoparticles can realize the double regulation of drug action and photothermal effect to immune microenvironment by the near infrared light treatment of lesion area, so as to effectively improve the treatment effect of ulcerative colitis.

[0086] It should be noted that when the present application claims involve numerical ranges, both endpoints of each numerical range and any number between the two endpoints can be selected, and in order to prevent repetition, the present application describes preferred embodiments.

[0087] Although preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0088] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A biomimetic nanoparticle having a function of treating ulcerative colitis, characterized by comprising a phospholipid, a cholesterol, and a fatty acid, and further comprising a drug for treating ulcerative colitis. Coating the drug-loaded nanoparticles with cell membranes is obtained; The drug-loaded nanoparticles are prepared by an organic photo-functional molecule, an anti-inflammatory drug and a surfactant; the fluorescence absorption peak and the fluorescence emission peak of the organic photo-functional molecule are at 780nm-2526nm; the mass concentration ratio of the organic photo-functional molecule to the anti-inflammatory drug is 1:1-25; the mass concentration ratio of the organic photo-functional molecule to the surfactant is 1:3-15; The cell membrane is a macrophage membrane; The organic photo-functional molecule is a near-infrared conjugated oligomer, and the structural formula of the near-infrared conjugated oligomer is: ； The anti-inflammatory drug is dexamethasone; The surfactant is DSPE-PEG2000; The ratio of the cell membrane to the drug-loaded nanoparticles is 1:9-11.

2. The method of claim 1, wherein the biomimetic nanoparticle is prepared by, The steps include: The organic photo-functional molecule, the anti-inflammatory drug and the surfactant are mixed, dialyzed in a dialysis bag with a molecular weight cut-off of 3500da, and then centrifuged using an ultrafiltration tube with a molecular weight cut-off of 5-10 times the molecular weight of the anti-inflammatory drug to obtain drug-loaded nanoparticles; The cell membrane and the drug-loaded nanoparticles are mixed at a weight ratio of 1:9-11, and reacted for 25-35min to realize coating of the drug-loaded nanoparticles with the cell membrane, thereby obtaining biomimetic nanoparticles.

3. The use of the biomimetic nanoparticles of claim 1 in the preparation of a drug for treating ulcerative colitis.

4. The use of the biomimetic nanoparticles of claim 1 in the preparation of a light-responsive drug for treating ulcerative colitis.

5. Use according to claim 3 or claim 4, characterised in that, The biomimetic nanoparticles regulate macrophage polarization.

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