A photothermal nanoparticle PT6 NPs and its application in the preparation of thermosensitive hydrogels

Abstract

This invention discloses a photothermal nanoparticle PT6 NPs and its application in the preparation of thermosensitive hydrogels. The photothermal nanoparticles PT6 NPs of this invention possess good photothermal stability and blood compatibility. When combined with poloxamer and functional components, they can be used to prepare a thermosensitive hydrogel. This hydrogel has a three-dimensional porous structure, enabling the loading and release of various active ingredients with high tunability. Its high water content provides excellent hydration and moisturizing properties. Furthermore, after near-infrared laser irradiation, the hydrogel exhibits good inhibition of drug-resistant bacteria. Therefore, the preparation of thermosensitive hydrogels using the photothermal nanoparticles PT6 NPs of this invention has promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, and more specifically, to a photothermal nanoparticle PT6 NPs and its application in the preparation of thermosensitive hydrogels. Background Technology

[0002] In recent years, skincare has become a daily habit for most consumers, with common product categories including serums, creams, and masks. As a delivery medium, masks can create a relatively closed environment, enhancing the absorption of active ingredients. However, traditional sheet masks suffer from poor skin adhesion and low utilization of active ingredients.

[0003] Hydrogels are hydrophilic porous materials with a three-dimensional network structure, characterized by softness, high water content, and good biocompatibility. The numerous hydrophilic groups in hydrogels can absorb a large number of water molecules, and their uniform pore structure can effectively load and release active ingredients, thus making them a promising candidate for use in face masks. Based on this, thermosensitive hydrogels have been developed. These hydrogels are sensitive to temperature changes and can undergo a sol-gel transition at specific temperatures, resulting in changes in volume and swelling. This allows for the stable delivery of active ingredients, enhancing the user experience and effectiveness. Based on the raw materials used in their synthesis, hydrogels can be classified into synthetic polymer hydrogels, natural polymer hydrogels, and natural / synthetic composite hydrogels.

[0004] However, most thermosensitive hydrogels currently undergo complex synthesis processes, making large-scale production difficult, and the use of cross-linking agents can easily cause inflammatory reactions or other adverse reactions.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide photothermal nanoparticles PT6 NPs and their application in the preparation of thermosensitive hydrogels. By utilizing the characteristic that the PT6 NPs loaded in the thermosensitive hydrogel of this invention can rapidly heat up under near-infrared light activation, the sol-gel transition and the controlled and sustained release of the active ingredients therein can be achieved.

[0007] This invention is implemented as follows:

[0008] In a first aspect, the present invention provides a photothermal oligomer molecule PT6, wherein the thiophene on the donor contains a 6-C alkyl chain, hence the name PT6, and its structural formula is shown below:

[0009] (1).

[0010] Secondly, the present invention provides photothermal nanoparticles PT6 NPs, which are formed by the self-assembly of the aforementioned photothermal oligomer molecule PT6 to form photothermal nanoparticles PT6 NPs with a nanostructure.

[0011] Thirdly, the present invention provides the application of the above-mentioned photothermal nanoparticles PT6 NPs in drug loading.

[0012] Fourthly, the present invention provides a thermosensitive hydrogel comprising: the aforementioned photothermal nanoparticles PT6 NPs, poloxamer, and functional components.

[0013] Fifthly, the present invention provides a method for preparing the above-mentioned thermosensitive hydrogel, which includes: adding functional components to poloxamer sol in an ice bath environment, mixing well, adding photothermal nanoparticles PT6 NPs, and mixing well again to obtain the thermosensitive hydrogel.

[0014] Sixthly, the present invention provides the application of the above-mentioned thermosensitive hydrogel in the preparation of antioxidant products.

[0015] In a seventh aspect, the present invention provides the application of the above-mentioned thermosensitive hydrogel in the preparation of anti-drug-resistant bacteria products.

[0016] The present invention has the following beneficial effects:

[0017] This invention utilizes photothermal nanoparticles PT6 NPs, made from the photothermal oligomer PT6, which possess excellent photothermal properties. When combined with poloxamer, they can be used to prepare a near-infrared light-activated thermosensitive hydrogel. This hydrogel has a three-dimensional porous structure, enabling the loading and release of various active ingredients with high tunability. Its high water content provides excellent hydration and moisturizing properties. After near-infrared laser irradiation, the hydrogel exhibits good inhibition of drug-resistant bacteria. Furthermore, it demonstrates good blood compatibility and extremely low biotoxicity. Therefore, the use of the photothermal nanoparticles PT6 NPs of this invention to prepare thermosensitive hydrogels shows promising application prospects. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is the synthesis route for PT6 in this invention;

[0020] Figure 2The 1H NMR spectrum of PT6 in Example 1;

[0021] Figure 3 The 1H NMR spectrum of compound 1 in Example 1;

[0022] Figure 4 The 1H NMR spectrum of compound 2 in Example 1;

[0023] Figure 5 The UV absorption spectrum of PT6 NPs in Example 1;

[0024] Figure 6 The size distribution of PT6 NPs and the corresponding TEM images in Example 1;

[0025] Figure 7 The image shows the sol-gel transition of the PF7 hydrogel in Example 2;

[0026] Figure 8 The data are the temperature-induced rheological data of the PF5~PF9 hydrogels in Experiment Example 2;

[0027] Figure 9 SEM images of PF5~PF9 hydrogels in Experiment Example 2;

[0028] Figure 10 DPPH scavenging rate data for PF@GA hydrogels with different concentrations of GA added in Experiment Example 2;

[0029] Figure 11 ABTS scavenging rate data for PF@GA hydrogels with different concentrations of GA added in Experiment Example 2;

[0030] Figure 12 The data on the in vitro GA release of the PF@GA hydrogel in Experiment Example 2;

[0031] Figure 13 The image shows the sol-gel transition of the PF@GA hydrogel in Experiment Example 2 after 7 days of storage.

[0032] Figure 14 The temperature-induced rheological data of the PF@GA-PT6 hydrogel in Experiment Example 3;

[0033] Figure 15 The image shows the SEM image of the PF@GA-PT6 hydrogel in Experiment Example 3.

[0034] Figure 16 DPPH scavenging rate data for PF@GA-PT6 hydrogels with different concentrations of GA added in Experiment Example 3;

[0035] Figure 17ABTS scavenging rate data for PF@GA-PT6 hydrogels with different concentrations of GA added in Experiment Example 3;

[0036] Figure 18 The data on the in vitro GA release from the PF@GA-PT6 hydrogel in Experiment Example 3;

[0037] Figure 19 The image shows the sol-gel transition of the PF@GA hydrogel in Experiment Example 3 after 7 days of storage.

[0038] Figure 20 The photothermal property characterization data of the PF@GA-PT8 hydrogel in Experiment Example 4;

[0039] Figure 21 The photothermal property characterization data of PF@GA-PT6 hydrogel in Experiment Example 4;

[0040] Figure 22 The antimicrobial resistance data of PF@GA-PT6 hydrogel in Experiment Example 5;

[0041] Figure 23 The data are from the hemolysis experiment of PF@GA-PT6 hydrogel in Experiment Example 6. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0043] During the experiment, this invention yielded a novel photothermal oligomer molecule, named PT6, with the following structural formula:

[0044] (1).

[0045] The preparation route of the above-mentioned photothermal oligomer PT6 is as follows: Figure 1 As shown, the photothermal nanoparticles prepared from it are named PT6 NPs, and the preparation steps of PT6 NPs are as follows:

[0046] S1. Under the protection of an inert gas, phosphorus oxychloride was added to cooled anhydrous N,N-dimethylformamide (DMF). After the reaction, compound 1 and 1,2-dichloroethane were added, and the mixture was refluxed overnight. After cooling to room temperature, the reaction was quenched with water, and then extracted with dichloromethane. The organic layer was collected, washed, dried and purified to obtain a yellow solid (i.e., compound 2).

[0047] Compound 1 used in the above steps can be prepared by the method described in ACS Appl. Mater. Interfaces 2022, 14, 36, 41296–41303.

[0048] S2. Compound 2 obtained in S1 was mixed with (5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (2FIC), and chloroform was added under the protection of an inert gas. After complete dissolution, pyridine was added, the mixture was refluxed, cooled, and the crude product was washed with methanol. After purification, a dark blue solid, PT6, was obtained.

[0049] S3. Dissolve the PT6 obtained in S2 in tetrahydrofuran (THF) and react it with 1,2-distearate-sn-glycerol-3-phosphate ethanolamine-polyethylene glycol 2000 (DSPE-PEG). 2000 The PT6 NPs were obtained by mixing the PT6 NPs with a THF solution, adding deionized water, and then sonicating.

[0050] During the research, it was found that the above-mentioned photothermal nanoparticles have good photothermal stability and blood compatibility. Therefore, the above-mentioned photothermal nanoparticles were prepared into hydrogels for loading related drugs.

[0051] Based on the above, the present invention provides a thermosensitive hydrogel comprising the aforementioned photothermal nanoparticles, poloxamer, and functional molecules, wherein the functional molecules are the relevant drugs to be loaded.

[0052] Pluronic is a polyoxyethylene-polyoxypropylene ether block copolymer, a high-molecular-weight nonionic surfactant. Its polyol structure gives it excellent water solubility. Pluronic F127 (PF127) and Pluronic F68 (PF68) are biocompatible and can be used in vivo. The structures of these two polymers are: x=z=101, y=56 for PF127; x=z=80, y=27 for PF68. The combination of PF127 and PF68 can exhibit a sol-gel transition at specific temperatures. This invention selects these two pluronic polymers and combines them with photothermal nanoparticles PT6 NPs. PT6 NPs convert light energy into heat energy, increasing the ambient temperature, thereby causing the sol to transform into a hydrogel under elevated temperature conditions. This achieves controlled and sustained release of the active ingredient, improving the utilization rate and user experience.

[0053] The thermosensitive hydrogel prepared using the above-mentioned components has a three-dimensional porous structure, enabling the loading and release of various active ingredients with extremely high adjustability. Simultaneously, its high water content gives the hydrogel excellent hydrating and moisturizing properties.

[0054] In some embodiments, the mass ratio of PF127 to PF68 is (5-9):1. Preferably, the mass ratio of PF127 to PF68 is 7:1. Experiments have shown that when the mass ratio is 7:1, the hydrogel can rapidly achieve a sol-gel transition at 33°C.

[0055] In some embodiments, the aforementioned functional molecule is gallic acid (GA). Thermosensitive hydrogels loaded with gallic acid prepared using the above-mentioned components can prevent skin damage caused by free radicals and protect the skin from damage caused by ultraviolet radiation, air pollution, and other external factors. Furthermore, the reversible temperature control of the hydrogel enhances the user experience and facilitates transportation.

[0056] It should be noted that the above-mentioned functional molecules can also be other antioxidants or other active substances with other effects, and are not limited to gallic acid. Those skilled in the art can adjust the type and amount of functional molecules according to actual needs.

[0057] In some embodiments, the mass ratio of PF127, PF68, functional molecules and photothermal nanoparticles PT6 NPs can be adjusted to 56000:8000:100~1000:1~2 as needed.

[0058] Meanwhile, the present invention provides a method for preparing the above-mentioned thermosensitive hydrogel, comprising: adding functional components to poloxamer sol in an ice bath environment, mixing well, adding photothermal nanoparticles PT6 NPs, and mixing well again to obtain the thermosensitive hydrogel.

[0059] The specific steps are as follows:

[0060] S1. Dissolve PF127 and PF68 sequentially in ultrapure water in an ice bath, stir until homogeneous to obtain PF sol, and store at 4 ℃ for later use.

[0061] The mass ratio of PF127 to PF68 is (5-9):1; preferably, the mass ratio of PF127 to PF68 is 7:1; and the final added mass fraction of PF68 is 4%.

[0062] S2. Add gallic acid to the prepared PF sol. Stir well in an ice bath to obtain PF@GA sol.

[0063] S3. Add photothermal nanoparticles PT6 NPs to the prepared PF@GA sol, stir evenly in an ice bath to obtain PF@GA-PT6 hydrogel.

[0064] The mass ratio of PF127, PF68, functional molecules and photothermal nanoparticles PT6 NPs is 56000:8000:100~1000:1~2.

[0065] The PF@GA-PT6 hydrogel prepared using the above method exhibited good photothermal stability after cyclic irradiation under near-infrared laser, indicating its reusability. Furthermore, after near-infrared laser irradiation, the hydrogel achieved an inhibition rate of over 99% against drug-resistant bacteria, demonstrating good inhibitory activity against such bacteria.

[0066] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0067] Example 1

[0068] This embodiment describes the photothermal nanoparticles PT6 NPs and their preparation method, as detailed below:

[0069] (1) Synthesis of PT6

[0070] Anhydrous N,N-dimethylformamide (DMF, 10 mL) was added to a dry 100 mL double-necked round-bottom flask. After cooling to 0 °C and stirring, phosphorus oxychloride (POCl3, 2 mL) was added using a syringe under argon protection. After 2 h, compound 1 (380 mg, 0.334 mmol) and dry 1,2-dichloroethane (20 mL) were added. The mixture was refluxed overnight. After cooling to room temperature, 100 mL of water was added to quench the reaction. The mixture was extracted with dichloromethane, the organic layer was collected, washed with water, and dried over anhydrous sodium sulfate. After removing the solvent under reduced pressure, the mixture was purified by column chromatography to give a yellow solid (278 mg, yield: 70%).

[0071] Compound 2 (50 mg, 0.041 mmol) and 2FIC (50 mg, 0.215 mmol) were added sequentially to a two-necked flask, and the mixture was purged three times. Chloroform (20 mL) was then added under argon (Ar) atmosphere, and the mixture was stirred for 5 min to ensure complete dissolution of both compounds. Pyridine (0.5 mL) was then added, and the solution slowly turned green. The mixture was refluxed at 65 °C for 24 h, and after cooling, most of the solvent was evaporated. The crude product was then washed with methanol to remove excess 2FIC, and column chromatography was used to obtain a deep blue solid (0.309 g, yield: 90%), which was PT6.

[0072] (2) Preparation of PT6 NPs

[0073] PT6 NPs were prepared using a typical nanoprecipitation method. 0.3 mL of PT6 in THF solution (1 mg / mL, dissolved in THF) was mixed with 0.1875 mL of DSPE-PEG. 2000(16 mg / mL, dissolved in THF) Mix thoroughly. Add the resulting mixture rapidly to 10 mL of deionized water and sonicate in an ultrasonic bath for 2 h to obtain PT6 NPs with a final concentration of 100 μg / mL. Finally, the NPs are further processed by filtration through a 0.45 μm PVDF syringe.

[0074] (3) NMR characterization of PT6

[0075] like Figure 2 , for NMR characterization of PT6. 1 H NMR (600 MHz, CDCl3) δ 9.15 (s, 1H), 9.02 (s, 1H), 8.57 (s, 2H), 7.70 (s, 2H), 4.70 (d, J = 59.2 Hz, 5H), 3.22 (s, 4H), 3.03 (s, 2H), 1.92 (dd, J = 128.0, 68.8 Hz, 8H), 1.55 (s, 13H), 1.37 – 1.10 (m, 28H), 1.05 – 0.80 (m, 19H), 0.75 – 0.56 (m, 12H).

[0076] like Figure 3 NMR characterization of compound 1. 1 H NMR (400 MHz, CDCl3) δ 9.12 (s, 1H), 8.98 (s, 1H), 8.53 (dt, J = 10.3, 6.1 Hz, 2H), 7.73–7.63 (m, 2H), 7.33 (s, 1H), 4.76 (s, 2H), 4.67 (d, J = 7.0 Hz, 2H), 3.21 (s, 4H), 3.02 (t, J = 7.6 Hz, 2H), 2.12 (s, 2H), 1.95 (s, 2H), 1.87 (s, 2H), 1.76 (s, 2H), 1.57 (s, 6H), 1.48(s, 7H), 1.36 (s, 9H), 1.25 (s, 24H), 1.04 (s, 10H), 0.92 (s, 4H), 0.86 (s, 7H), 0.75 (s, 6H), 0.68 (s, 6H).

[0077] like Figure 4 NMR characterization of compound 2. 1H NMR (400 MHz, CDCl3) δ 10.13 (s, 1H), 10.04 (s, 1H), 7.13 (s, 1H), 5.28 (s, 4H), 4.64 (s, 4H), 3.18 (s, 2H), 3.05 (s, 2H), 2.99 (t, J = 7.7 Hz, 2H), 2.03 (s, 3H), 1.90 (d, J = 8.3 Hz, 5H), 1.74 (d, J = 7.4 Hz, 3H), 1.46 (dq, J = 15.6, 7.7 Hz, 7H), 1.40–1.32 (m, 9H), 1.25 (s, 30H), 0.91 (s, 15H), 0.88–0.80 (m, 10H), 0.67 (d, J = 2.3 Hz, 8H), 0.61 (d, J = 7.2 Hz, 6H).

[0078] (4) Ultraviolet absorption spectrum scan of PT6 NPs

[0079] The UV-Vis absorption spectra of the NPs solution were measured using a UV-Vis absorption spectrometer. The test wavelength was set to 400–1000 nm, and the scan rate was medium. The NPs solution was diluted to 25 μg / mL and tested in a quartz cuvette.

[0080] Depend on Figure 5 As can be seen, PT6 NPs exhibit a broad and strong absorption in the near-infrared region, with the strongest absorption at 720 nm. This is because the donor structure of PT6 contains thiophene with a decyl group, which endows it with a strong electron-donating ability and promotes the redshift of the absorption of PT6 NPs.

[0081] (5) Particle size and apparent morphology characterization of PT6 NPs

[0082] The hydrodynamic diameter of PT6 NPs was measured using dynamic light scattering (DLS), and the structural morphology of PT6 NPs was measured using transmission electron microscopy (TEM).

[0083] Depend on Figure 6 It can be seen that PT6 NPs are uniformly dispersed spheres with an average particle size of 76 nm.

[0084] Example 2

[0085] This embodiment describes a thermosensitive hydrogel and its preparation method, as detailed below:

[0086] (1) In an ice bath, PF127 and PF68 were dissolved sequentially in ultrapure water, stirred until homogeneous, and the resulting PF sol was stored at 4°C for later use. The final mass fraction of PF68 added was 4%, and the mass ratio of PF127 to PF68 was 7:1. Figure 7 As shown, it is a sol-gel transition image of PF7 hydrogel.

[0087] (2) Add gallic acid (GA) to the prepared PF sol. Stir evenly in an ice bath to obtain a PF@GA sol with a gallic acid concentration of 500 μg / mL.

[0088] (3) Add photothermal nanoparticles PT6 NPs to the prepared PF@GA sol and stir evenly in an ice bath to obtain PF@GA-PT6 hydrogels with PT6 NPs concentrations of 0, 5, 7.5 and 10 μg / mL.

[0089] Comparative Example 1

[0090] The difference from Example 2 is that PT8 NPs are used instead of PT6 NPs, and its structural formula is shown below:

[0091] (2).

[0092] Experimental Example 1

[0093] The performance differences of PF sols prepared at different addition ratios are compared as follows:

[0094] PF127 and PF68 were dissolved sequentially in ultrapure water in an ice bath, and the mixture was stirred until homogeneous to obtain PF sol, which was then stored at 4°C for later use. Based on the mass ratio of PF127 to PF68, they were named PF5 (5:1), PF6 (6:1), PF7 (7:1), PF8 (8:1), and PF9 (9:1), respectively, with a fixed final mass fraction of PF68 of 4%.

[0095] Different concentrations of gallic acid (GA) were added to the prepared PF sol at concentrations of 0 μg / mL, 250 μg / mL, 500 μg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, and 8 mg / mL. The mixture was stirred thoroughly in an ice bath to obtain the PF@GA sol.

[0096] (1) Rheological property testing of PF@GA hydrogel

[0097] The modulus and viscosity changes of PF5-PF9 hydrogels were determined using an Anton Paar MCR92 rheometer. The rheometer temperature was increased from 0℃ to 60℃, and the elastic modulus (G'), loss modulus (G''), and viscosity values ​​were recorded every 20 s. Temperature-modulus curves were plotted.

[0098] Depend on Figure 8 As can be seen, the phase transition temperatures of PF5 to FP9 are 40℃, 38℃, 33℃, 26℃, and 21℃, respectively. The PF7 hydrogel exhibits low viscosity and a loss modulus lower than its elastic modulus at temperatures between 0 and 25℃, indicating that PF7 is in an easily spreadable sol-gel state at low temperatures. When the temperature rises to 32℃, the viscosity of PF7 begins to increase sharply; when the temperature rises to 35℃, the viscosity increase of PF7 slows down and tends to stabilize. At this point, the elastic modulus is higher than the loss modulus, indicating that PF7 achieves a rapid sol-gel transition within a short time.

[0099] (2) Microstructure test of PF hydrogel:

[0100] PF sols of different mass ratios were placed in an incubator at 37°C for 15 min to obtain PF hydrogels, which were then rapidly frozen at -80°C for 3 h and freeze-dried for 48 h. The freeze-dried hydrogel samples were directly attached to conductive adhesives, sputtered with gold, and their morphology was captured by SEM.

[0101] Depend on Figure 9 As can be seen, the network structure of PF5 and PF6 hydrogels collapsed. PF8~PF9 hydrogels have a uniformly distributed three-dimensional network structure, which can effectively load and release active ingredients. Combined with phase transition, PF7 hydrogel was finally selected for subsequent active ingredient loading and named PF@GA hydrogel.

[0102] (3) Determination of DPPH free radical scavenging rate of PF@GA hydrogel:

[0103] The DPPH radical scavenging capacity of GA solution and PF@GA hydrogel was determined spectrophotometrically. GA loading concentrations were 0 μg / mL, 250 μg / mL, 500 μg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, and 8 mg / mL. Two mL of PF@GA sol was placed in a 10 mL test tube and incubated at 37°C for 30 min to form a gel. Two mL of DPPH-ethanol solution (400 μM) was added and mixed thoroughly. After reacting at 37°C in the dark for 30 min, the wavelength was measured at 517 nm. The DPPH scavenging rate was calculated using the following formula.

[0104]

[0105] Where A is the absorbance of the DPPH and sample mixture solution;

[0106] C is the absorbance of the sample and the solvent ethanol mixture;

[0107] B is the absorbance of the DPPH and ethanol mixture.

[0108] from Figure 10 It can be seen that the hydrogel's DPPH removal ability is lower than that of the corresponding concentration of GA solution, but only 500 μg / mL is needed to remove 95% of DPPH.

[0109] (4) Determination of ABTS free radical scavenging rate of PF@GA hydrogel:

[0110] The ABTS radical scavenging capacity of GA solution and PF@GA hydrogel was determined spectrophotometrically. GA loading concentrations were 0 μg / mL, 250 μg / mL, 500 μg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, and 8 mg / mL. Two mL of PF@GA sol was placed in a 10 mL test tube and incubated at 37°C for 30 min to form a gel. Two mL of ABTS-ethanol solution (1.4 mM) was added and mixed thoroughly. After reacting at 37°C in the dark for 30 min, the wavelength was measured at 734 nm. The ABTS scavenging rate was calculated using the following formula.

[0111]

[0112] Where A is the absorbance of the ABTS and sample mixture solution;

[0113] C is the absorbance of the sample and the solvent ethanol mixture;

[0114] B represents the absorbance of the ABTS and ethanol mixture.

[0115] from Figure 11 It can be seen that the ABTS removal capacity of the hydrogel is lower than that of the GA solution at the corresponding concentration, but only 500 μg / mL is needed to remove nearly 100% of the ABTS. The final concentration of GA in the PF@GA hydrogel was determined to be 500 μg / mL.

[0116] The hydrogel with a GA concentration of 500 μg / mL and a PF127 to PF68 mass ratio of 7:1 selected in the above experiments was further validated as follows:

[0117] (5) Determination of water content of PF@GA hydrogel:

[0118] The PF@GA sol was placed in a 37℃ incubator for 15 min to obtain the PF@GA hydrogel. The weight of the hydrogel at this point was recorded as A. The hydrogel was then rapidly frozen at -80℃ for 3 h and freeze-dried for 48 h, and the weight was recorded as B. The water content of the hydrogel was calculated using the following formula:

[0119]

[0120] The calculated water content of the PF@GA hydrogel is 68%.

[0121] (6) Investigation on the release of active ingredients from PF@GA hydrogel:

[0122] The in vitro release rate of PF@GA hydrogel was determined by ultraviolet absorption method. 1 mL of PF@GA sol was accurately pipetted into 13 centrifuge tubes, 3 mL of ultrapure water was added, and the tubes were placed in a 37℃ constant temperature shaker at a speed of 100 r / min. 1.5 mL samples were taken at 0, 1, 2, 3, 4, 5, 6, 12, 24, 36, 48, 60, and 72 h, and the release rate of the active ingredient was calculated using ultraviolet absorption method.

[0123] from Figure 12 It can be seen that GA can achieve long-term release within 72 days.

[0124] (7) Preliminary stability test of PF@GA hydrogel:

[0125] PF@GA hydrogels were dissolved in ultrapure water, physiological saline, and PBS, respectively. The vials were sealed and stored at 4°C for 7 days. The changes in the samples in each vial were observed.

[0126] like Figure 13 As shown, compared with day 1, 1 mL of PF@GA sol could still form a gel at 37℃ after being refrigerated in water, physiological saline, and PBS for 7 days, and the gel was uniformly dispersed without clumping or layering, indicating that PF@GA has good initial stability.

[0127] Experimental Example 3

[0128] (1) Rheological property test of PF@GA-PT6 hydrogel

[0129] The modulus change of PF@GA-PT6 hydrogel was determined using an Anton Paar MCR92 rheometer. The rheometer temperature was increased from 10℃ to 60℃, and the elastic modulus (G') and loss modulus (G'') were recorded every 20 s. Temperature-modulus curves were plotted.

[0130] Depend on Figure 14 It is evident that the phase transition temperature of the PF@GA-PT6 hydrogel remains at 33℃, indicating that the incorporation of PT6 NPs does not affect the phase transition temperature of the hydrogel and can still achieve sol-gel transformation in a short time.

[0131] (2) Microstructure test of PF@GA-PT6 hydrogel:

[0132] The PF@GA-PT6 hydrogel was rapidly frozen at -80℃ for 3 h and then freeze-dried for 48 h. The freeze-dried hydrogel sample was directly attached to a conductive adhesive, sputtered with gold, and the morphology of the PF hydrogel was photographed by SEM.

[0133] Depend on Figure 15 As can be seen, PF@GA-PT6 hydrogel has a uniformly distributed three-dimensional network structure, which can effectively load and release active ingredients.

[0134] (3) Determination of DPPH free radical scavenging rate of PF@GA-PT6 hydrogel:

[0135] The DPPH radical scavenging capacity of GA-PT6 NPs solution and PF@GA hydrogel was determined spectrophotometrically. GA loading concentrations were 0 μg / mL, 250 μg / mL, 500 μg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, and 8 mg / mL, respectively, while the PT6 NPs loading concentration was 10 μg / mL. Two mL of PF@GA sol was placed in a 10 mL test tube and incubated at 37°C for 30 min to form a gel. Two mL of DPPH-ethanol solution (400 μM) was added and mixed thoroughly. After reacting at 37°C in the dark for 30 min, the wavelength was measured at 517 nm. The DPPH scavenging rate was calculated using the following formula.

[0136]

[0137] Where A is the absorbance of the DPPH and sample mixture solution;

[0138] C is the absorbance of the sample and the solvent ethanol mixture;

[0139] B is the absorbance of the DPPH and ethanol mixture.

[0140] from Figure 16 It can be seen that the DPPH removal capacity of the hydrogel is lower than that of the corresponding concentration of GA-PT6 NPs solution. The hydrogel doped with PT6 NPs can still remove more than 95% of DPPH with only 500 μg / mL.

[0141] (4) Determination of ABTS free radical scavenging rate of PF@GA-PT6 hydrogel:

[0142] The ABTS radical scavenging capacity of GA-PT6 NPs solution and PF@GA-PT6 hydrogel was determined spectrophotometrically. GA loading concentrations were 0 μg / mL, 250 μg / mL, 500 μg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, and 8 mg / mL, respectively, while the PT6 NPs loading concentration was 10 μg / mL. Two mL of PF@GA sol was placed in a 10 mL test tube and incubated at 37°C for 30 min to form a gel. Two mL of ABTS-ethanol solution (1.4 mM) was added and mixed thoroughly. After reacting at 37°C in the dark for 30 min, the wavelength was measured at 734 nm. The ABTS scavenging rate was calculated using the following formula.

[0143]

[0144] Where A is the absorbance of the ABTS and sample mixture solution;

[0145] C is the absorbance of the sample and the solvent ethanol mixture;

[0146] B represents the absorbance of the ABTS and ethanol mixture.

[0147] from Figure 17 It can be seen that the ABTS removal capacity of the hydrogel is lower than that of the corresponding concentration of GA-PT6 NPs solution. The hydrogel doped with PT6 NPs can still remove more than 99% of ABTS with only 500 μg / mL.

[0148] (5) Determination of water content of PF@GA-PT6 hydrogel:

[0149] Weigh the PF@GA-PT6 hydrogel, weight A. Record the weight after quick-freezing at -80℃ for 3 hours and freeze-drying for 48 hours as B. Calculate the water content of the hydrogel using the following formula:

[0150]

[0151] Calculations showed that the water content of the PF@GA-PT6 hydrogel was still 68%, indicating that the trace addition of PT6 NPs did not affect the water content of the hydrogel.

[0152] (6) Investigation on the release of active ingredients from PF@GA-PT6 hydrogel:

[0153] The in vitro release rate of PF@GA-PT6 hydrogel was determined by ultraviolet absorption method. 1 mL of PF@GA-PT6 sol was accurately pipetted into 13 centrifuge tubes, 3 mL of ultrapure water was added, and the tubes were placed in a 37℃ constant temperature shaker with a rotation speed of 100 r / min. 1.5 mL samples were taken at 0, 1, 2, 3, 4, 5, 6, 12, 24, 36, 48, 60, and 72 h, and the release rate of the active ingredient was calculated using ultraviolet absorption method.

[0154] from Figure 18 It can be seen that the PF@GA-PT6 hydrogel exhibits the same sustained-release GA as the PF@GA-PT6 hydrogel, achieving long-term release of GA within 72 hours.

[0155] (7) Preliminary stability test of PF@GA-PT6 hydrogel:

[0156] PF@GA-PT6 hydrogels were dissolved in ultrapure water, physiological saline, and PBS, respectively. The vials were sealed and stored at 4°C for 7 days. The changes in the samples in each vial were observed.

[0157] like Figure 19 As shown, compared with day 1, 1 mL of PF@GA-PT6 sol could still form a gel at 37℃ after being refrigerated in water, physiological saline, and PBS for 7 days, and the gel was uniformly dispersed without clumping or layering, indicating that PF@GA-PT6 has good initial stability.

[0158] Experiment Example 4

[0159] The photothermal properties of the hydrogels prepared in Example 3 and Comparative Example 1 were characterized, and the specific steps are as follows:

[0160] Using 808 nm, 1.0 W / cm 2 Near-infrared lasers were used to irradiate PF@GA-PT6 and PF@GA-PT8 hydrogels at different concentrations (0, 5, 10, 20 μg / mL) for 5 min, with temperature changes recorded every 30 s. The effects of different laser power densities (0.5, 0.75, 1.0, 1.5 W / cm²) were also investigated. 2 The photothermal conversion properties of two hydrogels (5 μg / mL, 100 μL) under irradiation. At a power density of 1 W / cm². 2 100 μL of two types of hydrogels (5 μg / mL) were irradiated with an 808 nm near-infrared laser for 5 min. Temperature changes were measured every 30 s. After the laser irradiation was turned off, temperature change data were recorded again at the same time intervals, with a 5 min interval, and the on / off cycle was repeated 5 times.

[0161] from Figure 20It can be seen that the heating capacity of PF@GA-PT8 hydrogel is concentration- and light intensity-dependent, indicating that the heating capacity of PF@GA-PT8 hydrogel can be precisely controlled by adjusting the light power density and solution concentration. After five cycles of ON / OFF laser switching irradiation, the hydrogel of PF@GA-PT8 hydrogel exhibited good photothermal stability and can be reused.

[0162] from Figure 21 It can be seen that the heating capacity of PF@GA-PT6 hydrogel is concentration- and light intensity-dependent, indicating that the heating capacity of PF@GA-PT6 hydrogel can be precisely controlled by adjusting the light power density and solution concentration. After five cycles of ON / OFF laser switching irradiation, the hydrogel of PF@GA-PT6 hydrogel exhibited good photothermal stability and can be reused.

[0163] Experimental Example 5

[0164] The photothermal antimicrobial properties of the PF@GA-PT6 hydrogel prepared in Example 3 were characterized as follows:

[0165] First, add 20 μL of Ampoules r E. coli (OD) 600 =1.0) and different concentrations of PF@GA-PT6 hydrogel (0, 5, 7.5, 10 μg / mL) were incubated in the dark at 37°C for 30 min. Then these Amp r E. coli The suspension was placed in the dark or under 808 nm laser irradiation, with an irradiance of 550 mW / cm². 2 Irradiate for 5 minutes. Finally, dilute each group with PBS solution at a concentration of 5 × 10⁻⁶. 4 Then, spread 100 µL of the diluted solution onto LB solid agar plates and incubate at 37°C for 16–18 h to allow colonies to form. MRSA and Amp r E. coli The procedure is the same. The inhibition rate (IR) is determined using the following formula:

[0166] IR = (C-C0) / C0 × 100%

[0167] In the formula, C represents the colony-forming units (CFU) of the experimental group, and C0 represents the number of colony-forming units of the control group.

[0168] from Figure 22 It can be seen that, under dark conditions, the inhibition rates of hydrogels with different PT6 NPs concentrations against both drug-resistant bacteria were less than 10%, and the PF@GA-PT6 hydrogel itself had almost no dark toxicity. (At 808 nm, 550 mW / cm²) 2After 10 min of near-infrared light irradiation, the PF@GA-PT6 hydrogel with a PT6 NPs concentration of 10 μg / mL showed resistance to Amp r E. coli Both MRSA and MRSA have antibacterial rates of over 99%, effectively eliminating infections caused by drug-resistant bacteria.

[0169] Experimental Example 6

[0170] The blood compatibility of the PF@GA-PT6 hydrogel prepared in Example 3 was characterized as follows:

[0171] One mL of fresh rabbit blood was centrifuged at 5000 rpm for 10 min to remove the supernatant and intermediate leukocytes. 20 μL of the blood cell pellet was added to 980 μL of physiological saline to prepare a 2% erythrocyte solution. 20 μL of Triton X100 was added to the positive control group, and physiological saline was used as the solvent for the negative control. The same proportion of PF@GA-PT6 hydrogel was added to the experimental groups. After mixing and standing for 3 h, the mixture was centrifuged at 10,000 rpm for 2 min, and the supernatant was collected and the absorbance at 541 nm was measured in a 96-well plate. The hemolysis rate (%) was calculated using the following formula:

[0172]

[0173] In the formula, I is the absorbance of the sample itself, I0 is the absorbance of the negative control, and I′ is the absorbance of the positive control.

[0174] from Figure 23 It can be seen that the hemolysis rate of PF@GA-PT6 hydrogels at different concentrations is far below 5%, indicating excellent blood compatibility.

[0175] 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. The application of photothermal nanoparticles PT6 NPs with nanostructures formed by the self-assembly of photothermal oligomer PT6 molecules in the preparation of thermosensitive hydrogels, characterized in that, The thermosensitive hydrogel includes the photothermal oligomer molecule PT6, poloxamer, and functional components; The structural formula of the photothermal oligomer PT6 is shown below: （1）； The poloxamer comprises PF127 and PF68, with a mass ratio of PF127 to PF68 of 7:

1.

2. A temperature-sensitive hydrogel, characterized in that, include: Photothermal nanoparticles PT6 NPs, poloxamer, and functional ingredients; The photothermal nanoparticles PT6 NPs have a nanostructure formed by the self-assembly of photothermal oligomer molecules PT6, and the structural formula of the photothermal oligomer molecules PT6 is shown below: （1）； The poloxamer comprises PF127 and PF68, with a mass ratio of PF127 to PF68 of 7:

1.

3. The thermosensitive hydrogel according to claim 2, characterized in that, The mass ratio of PF127, PF68, functional molecules and photothermal nanoparticles PT6 NPs in the thermosensitive hydrogel is 56000:8000:100~1000:1~2.

4. The method for preparing the thermosensitive hydrogel as described in claim 2 or 3, characterized in that, include: In an ice bath environment, functional components are added to poloxamer sol, mixed well, and then photothermal nanoparticles PT6 NPs are added. After mixing again, a thermosensitive hydrogel can be obtained.

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