A gold nanorod composite Fmoc-L-tyrosine hydrogel, its preparation method and application

Abstract

This invention discloses a gold nanorod composite Fmoc-L-tyrosine hydrogel, its preparation method, and its applications. The method includes the following steps: S1. Dissolving Fmoc-L-tyrosine in PBS buffer or PB buffer at pH 7.00-9.00, followed by vortex heating and sonication to obtain an Fmoc-L-tyrosine hydrogel precursor solution; S2. Mixing AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution, followed by vortex heating and sonication to obtain the gold nanorod composite Fmoc-L-tyrosine hydrogel. The method for preparing the hydrogel in this invention is simple. The introduction of gold nanorods enhances mechanical properties and significantly improves self-healing performance. Simultaneously, the prepared hydrogel exhibits multi-responsiveness, injectability, and excellent antibacterial properties, making it applicable to smart wound dressings, targeted drug delivery systems, and implantable bioelectronic devices.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, and particularly relates to a gold nanorod composite Fmoc-L-tyrosine hydrogel, its preparation method and application. Background Technology

[0002] Hydrogels, composed of three-dimensional cross-linked networks, are considered ideal injectable in-situ gels or wound dressings due to their high water content, good biocompatibility, porous structure, and adjustable mechanical strength. Amino acid-based supramolecular hydrogels are particularly favored in biomedical applications due to their excellent biosafety (e.g., low toxicity, good biocompatibility, and biodegradability) and suitable physicochemical properties (e.g., high water content and physiological stability).

[0003] While amino acid-based supramolecular hydrogels have enormous development potential, current technologies still have the following limitations in practical applications:

[0004] 1. Low mechanical strength: For example, the patent with publication number CN106890135A discloses a pH-responsive peptide-based hydrogel and its preparation method and application. Although the hydrogel is prepared by introducing glutaraldehyde chemical crosslinking agent and protein in the diphenylalanine system, the mechanical properties of its final product (G' is 10-700 Pa) are still at a low level, and it cannot provide effective physical support and protective barrier at the wound site.

[0005] 2. Difficulty in simultaneously achieving high mechanical properties and self-healing capabilities: To improve the mechanical strength of this type of hydrogel, a direct but technically flawed approach is to introduce irreversible chemical cross-linking (e.g., in patent CN112807483A, peptides self-assemble into nanofibers through non-covalent interactions, which then interweave to form a first network, while genipin and chitosan molecules chemically cross-link to form a second network). While this approach can increase modulus, the irreversible chemical cross-linking hinders the dynamic reorganization of the network after damage, resulting in a lack of self-healing ability in the hydrogel.

[0006] 3. Single response and complex preparation process: Traditional amino acid hydrogels have a single component, resulting in a single irritant response, which cannot meet the needs of multiple clinical applications. Therefore, multiple components need to be introduced, resulting in a variety of hydrogel components and a complex preparation process.

[0007] Gold nanorods are a typical anisotropic metallic nanomaterial, which can be regarded as a one-dimensional extension of gold nanoparticles. Under illumination, their surface free electrons undergo coherent oscillations, endowing them with tunable localized surface plasmon resonance properties. This one-dimensional structure results in two absorption peaks in the spectrum, with the longitudinal plasmon absorption peak located in the near-infrared region. Leveraging the photothermal effect in this wavelength range, gold nanorods can achieve multifunctional synergy, including photothermal therapy, triggering on-demand drug release, and biomedical imaging, demonstrating significant application potential in the biomedical field.

[0008] Based on the above background, the inventors of this invention are committed to constructing a novel hydrogel material with a simple method, high mechanical strength, high self-healing, multiple responsiveness, injectability, and efficient antibacterial function. Summary of the Invention

[0009] To address the shortcomings of the prior art, the present invention aims to provide a method for preparing and applying a gold nanorod composite Fmoc-L-tyrosine hydrogel.

[0010] The purpose of this invention is to provide a method for preparing gold nanorod composite Fmoc-L-tyrosine hydrogel, comprising the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer or PB buffer at pH 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution does not exceed 400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 15~25 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The molar concentration of the PBS buffer is 50-100 mM, and the molar concentration of the PB buffer is 50 mM. When the pH of the PBS buffer or PB buffer is 8.00 and the molar concentration of the Fmoc-L-tyrosine hydrogel precursor solution is 15 mmol / L, the mass concentration of the AuNRs aqueous solution is 100~400 μg / mL. When the pH of the PBS buffer or PB buffer is 9.00 and the molar concentration of the Fmoc-L-tyrosine hydrogel precursor solution is 20 mmol / L, the mass concentration of the AuNRs aqueous solution is 100~400 μg / mL.

[0011] In some embodiments of the present invention, the preparation method of gold nanorod composite Fmoc-L-tyrosine hydrogel includes the following steps: S1. Dissolve Fmoc-L-tyrosine in a buffer solution with a pH of 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution; S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution does not exceed 400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 30 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The buffer solution is selected from PBS buffer with a molar concentration of 50-100 mM or PB buffer with a molar concentration of 50 mM. Wherein, when the pH of the buffer solution is 7.00~8.00, the buffer solution is selected from PBS buffer with a molar concentration of 100 mM.

[0012] In some embodiments of the present invention, the preparation method of gold nanorod composite Fmoc-L-tyrosine hydrogel includes the following steps: S1. Dissolve Fmoc-L-tyrosine in a buffer solution with a pH of 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution; S2. Mix AuNRs aqueous solution and Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of AuNRs aqueous solution is 100~400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 10 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The buffer solution is selected from PBS buffer with a molar concentration of 10-50 mM or PB buffer with a molar concentration of 50 mM.

[0013] In some embodiments of the present invention, in S1, the temperature of the heating ultrasound is 80~100 ℃ and the time is 5~15 min.

[0014] In some embodiments of the present invention, in S2, the AuNRs plasma resonance absorption wavelength range is 400-1000 nm, the particle length is 40-80 nm, the particle width is 9-17 nm, and the aspect ratio is 3.8-5.1.

[0015] In some embodiments of the present invention, in S2, the temperature of the heating ultrasound is 80~100 ℃ and the time is 5~15 min.

[0016] In some embodiments of the present invention, in step S2, the preparation of the AuNRs includes the following steps: Silver nitrate solution, chloroauric acid solution, concentrated hydrochloric acid and hydroquinone were added to an aqueous solution of 1-hexadecyl-N,N-dimethylcyclohexammonium bromide. The reaction was carried out, and sodium borohydride solution was added to continue the reaction. After post-treatment, AuNRs were obtained.

[0017] In some embodiments of the present invention, the molar ratio of 1-hexadecyl-N,N-dimethylcyclohexammonium bromide to silver nitrate, tetrachloroauric acid, hydroquinone, and sodium borohydride is 400~600:1~2:4~6:300~500:2~4.

[0018] In some embodiments of the present invention, the hydrochloric acid has a mass fraction of 30% to 40%.

[0019] In some embodiments of the present invention, the hydrochloric acid has a mass fraction of 36% to 38%.

[0020] In some embodiments of the present invention, the reaction proceeds until the mixed solution becomes colorless and transparent.

[0021] In some embodiments of the present invention, the temperature for the continued reaction is 30-40 °C and the time is 20-30 hours.

[0022] Another objective of this invention is to provide a gold nanorod composite Fmoc-L-tyrosine hydrogel, which is prepared by the method described above.

[0023] Another objective of this invention is to provide the application of the aforementioned gold nanorod composite Fmoc-L-tyrosine hydrogel in the fields of smart wound dressings, targeted drug delivery systems, and implantable bioelectronic devices.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The hydrogel prepared in this invention, after introducing an aqueous solution of AuNRs into a Fmoc-L-tyrosine solution, the cationic surfactant on the surface of AuNRs serves as multiple physical cross-linking points, forming a strong electrostatic interaction with multiple negatively charged Fmoc-L-tyrosine nanofibers, which can effectively connect the originally loose nanofibers. At the same time, the hydrophobic alkyl chain of AuNRs has a hydrophobic interaction with the Fmoc group and benzene ring in the fiber network, so that Fmoc-L-tyrosine can construct a continuous three-dimensional gel network at a low molar concentration of 10 mmol / L.

[0025] (2) The composite hydrogel of the present invention has high mechanical properties and high self-healing properties. The hydrogel is formed by co-assembling AuNRs and Fmoc-L-tyrosine. The synergistic effect of the two is the key to endowing the hydrogel with high mechanical properties and high self-healing properties. On the one hand, the main driving force for the self-assembly of Fmoc-L-tyrosine into gel is the hydrophobic interaction between molecules, π-π stacking, and hydrogen bonding. On the other hand, the positive charge of AuNRs surfactant interacts strongly with the deprotonated carboxyl and hydroxyl groups in the Fmoc-L-tyrosine network, acting as heterogeneous nucleation sites and forming strong ionic crosslinking points. This results in the densification of the fiber network and the tight entanglement of multiple nanofibers to form large fiber clusters. At the same time, the hydrophobic alkyl chains of AuNRs interact with the Fmoc groups and benzene rings, further stabilizing the adsorption of AuNRs on the fiber surface. Therefore, these dynamic binding mechanisms can reversibly dissociate and recombine under external stimuli. This not only effectively dissipates energy through the sacrificial bond mechanism, significantly improving the toughness of the material (yield point increased from 4% to 11%) and the elastic energy storage capacity of the network (storage modulus increased by 6 times), but also promotes the recombination of the gel network during the self-healing process (after five large shear strain cycles, the self-healing recovery rate increased from 46% to 95%).

[0026] (3) The hydrogel prepared by this invention has a simple process. Using AuNRs and Fmoc-L-tyrosine as raw materials, a hydrogel with high mechanical strength, high self-healing properties, multiple responses (pH response, ionic strength response, and light response), injectability, and excellent antibacterial properties can be obtained simply by vortex mixing. The hydrogel preparation method of this invention is simple and environmentally friendly, and has broad application prospects in the fields of intelligent wound dressings, targeted drug delivery systems, and implantable bioelectronic devices. Attached Figure Description

[0027] Figure 1 To generate raw material molar concentration diagrams for different states of products in Examples 9-71 and Comparative Examples 1-87.

[0028] Figure 2 To generate raw material molar concentration diagrams for different states of products in Examples 72-133 and Comparative Examples 88-175.

[0029] Figure 3 To generate raw material molar concentration diagrams for different states of products in Examples 134-210 and Comparative Examples 176-248.

[0030] Figure 4 To generate raw material molar concentration diagrams for different states of products in Examples 211-273 and Comparative Examples 249-335.

[0031] Figure 5To generate a raw material molar concentration map of products in different states for comparative examples 336~485.

[0032] Figure 6 This is a TEM image of the gold nanorods prepared in Example 6.

[0033] Figure 7 The images show the ultraviolet spectra of the gold nanorod aqueous solutions prepared in Examples 1-4.

[0034] Figure 8 The images show the ultraviolet spectra of the gold nanorod aqueous solutions prepared in Examples 5-8.

[0035] Figure 9 The image shows a TEM image of the Fmoc-L-tyrosine hydrogel of Comparative Example 36 at 12000X.

[0036] Figure 10 This is a TEM image of the gold nanorod composite Fmoc-L-tyrosine hydrogel from Example 42 at 12000X.

[0037] Figure 11 This is a TEM image of gold nanorod composite Fmoc-L-tyrosine hydrogel in Example 45 at 12000X.

[0038] Figure 12 Images of the Fmoc-L-tyrosine hydrogel (left) of Comparative Example 4 and the gold nanorod composite Fmoc-L-tyrosine hydrogel (right) of Example 3.

[0039] Figure 13 The UV spectra of the gold nanorod aqueous solution prepared in Example 6 and the gold nanorod composite Fmoc-L-tyrosine hydrogel prepared in Example 42 are shown.

[0040] Figure 14 The hydrogel viscosity curves are for Comparative Example 36, Example 42, and Example 45.

[0041] Figure 15 The amplitude scanning curves are for Comparative Example 36, Example 42, and Example 51.

[0042] Figure 16 The above are frequency scan curves of the hydrogels in Comparative Example 36, Example 42, and Example 51.

[0043] Figure 17 The following are hydrogel step strain curves for Comparative Example 36, Example 42, and Example 51.

[0044] Figure 18 Amplitude scan curves of gold nanorod composite Fmoc-L-tyrosine hydrogels from Examples 42, 104, and 171 at different pH values.

[0045] Figure 19 Amplitude scan curves of gold nanorod composite Fmoc-L-tyrosine hydrogels from Examples 39 and 42 under different ionic intensities.

[0046] Figure 20 Amplitude scan curves of gold nanorod composite Fmoc-L-tyrosine hydrogels from Examples 40 and 42 under different buffer solutions.

[0047] Figure 21 This is a graph showing the pH response of gold nanorod composite Fmoc-L-tyrosine hydrogel in Example 42.

[0048] Figure 22 This is a colony count diagram of the hydrogel against Staphylococcus aureus.

[0049] Figure 23 The graph shows the inhibition rate of Staphylococcus aureus by the hydrogel.

[0050] Figure 24 Photothermal properties of the gold nanorod aqueous solution of Example 6, the Fmoc-L-tyrosine hydrogel of Comparative Example 36, and the gold nanorod composite Fmoc-L-tyrosine hydrogel of Example 42.

[0051] Figure 25 This is an injection diagram of gold nanorod composite Fmoc-L-tyrosine hydrogel in Example 67. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0053] The instruments used for the performance tests of the examples and comparative examples are as follows: The MCR 102 modular intelligent advanced rotational rheometer is sourced from Anton Paar (China) Co., Ltd. The JEM 2100F high-resolution field emission transmission electron microscope is from Nippon Electron Ltd. The U-3900 UV-Vis spectrophotometer is manufactured by Hitachi, Japan. The JEM-2100PLUS high-resolution field emission transmission electron microscope is from NEC Corporation; the S220Seven Compact series benchtop pH meter is from Mettler Toledo Instruments (Shanghai) Co., Ltd.

[0054] The 808 nm near-infrared LED light source is from Shenzhen Wocan Technology Co., Ltd. The DS-2TPH10-3AUF Hikvision temperature measuring instrument is from Hangzhou Hikvision Technology Co., Ltd. The reagents used in the examples and comparative performance tests are as follows: Silver nitrate (purity ≥99.7%), Sinopharm Chemical Reagent Co., Ltd.; Tetrachloroauric acid trihydrate (purity ≥99.9%), Shanghai Aladdin Biochemical Technology Co., Ltd.; Sodium borohydride (purity 98.0%), Tianjin Xinsheng Biochemical Technology Co., Ltd.; Hydroquinone (purity ≥99.7%), Shanghai Maclean Biochemical Technology Co., Ltd.; N,N-dimethylcyclohexylamine (purity 98.0%), 1-bromohexadecane (purity 98.0%), tris(hydroxymethyl)aminomethane (purity 99.0%), Shanghai Adamas Reagent Co., Ltd.; Fmoc-L-tyrosine (purity 98.0%), disodium hydrogen phosphate dodecahydrate (purity ≥99.7%), sodium dihydrogen phosphate dodecahydrate (purity ≥99.7%), Shanghai Aladdin Biochemical Technology Co., Ltd.; Sodium hydroxide (purity ≥98.0%), Shanghai Titan Technology Co., Ltd.; Concentrated hydrochloric acid (36 wt%~38 wt%) (wt%), Guangzhou Chemical Reagent Factory.

[0055] AuNRs represents gold nanorods.

[0056] The Fmoc group represents 9-fluorenemethyloxycarbonyl.

[0057] Fmoc-LY represents the Fmoc-L-tyrosine hydrogel precursor solution.

[0058] Examples 1-8 This embodiment provides an AuNRs, the raw materials and dosages of which are shown in Table 1: Table 1

[0059] Its preparation method includes the following steps: Take a 10 mL centrifuge tube, add 0.05 mol / L of 1-hexadecyl-N,N-dimethylcyclohexammonium bromide (DCMH) aqueous solution, then add 4 mmol / L of silver nitrate (AgNO3) solution, shake well, then add 10 mmol / L of tetrachloroauric acid (HAuCl4) solution, 5 μL of concentrated hydrochloric acid and 0.5 mol / L of hydroquinone, shake vigorously until the mixed solution becomes colorless and transparent, then add 0.15 mol / L of sodium borohydride (NaBH4) solution, shake well, incubate in a 35℃ constant temperature water bath for 24 hours, centrifuge at 10000 r / min for 10 minutes, wash the precipitate twice with ultrapure water, add ultrapure water to make up to 1 mL, shake well, and obtain AuNRs aqueous solution.

[0060] Examples 9-71 and Comparative Examples 1-87 This embodiment and comparative example provide a gold nanorod composite Fmoc-L-tyrosine hydrogel, the preparation method of which includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer, PB buffer, or Tris buffer at pH 7.40, vortex and sonicate at 90 °C for 10 min to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixed system, the mass concentration of the AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine are as follows: Figure 1 As shown, gold nanorod composite Fmoc-L-tyrosine hydrogel was prepared by vortex heating and sonication at 90 ℃ for 10 min. The molar concentrations of PBS buffer, PB buffer, or Tris buffer, the Fmoc-L-tyrosine hydrogel precursor solution, and the mass concentrations of AuNRs aqueous solution are as follows: Figure 1As shown, the mass concentration of AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine hydrogel precursor solution represent the concentration in the initial mixed system, not the added concentration. The order of the examples and comparative examples is from front to back, then from bottom to top, and finally from left to right. Examples are those where the mass concentration of AuNRs aqueous solution is greater than 0 μg / mL and a gel is formed; the rest are comparative examples. For example, Comparative Example 36 has a molar concentration of 20 mmol / L for the Fmoc-L-tyrosine hydrogel precursor solution, a molar concentration of 50 mM for the PBS buffer, and a mass concentration of 0 μg / mL for the AuNRs aqueous solution. Example 42 has a molar concentration of 20 mmol / L for the Fmoc-L-tyrosine hydrogel precursor solution, a molar concentration of 50 mM for the PBS buffer, and a mass concentration of 100 μg / mL for the AuNRs aqueous solution. If the mass concentration of the aqueous solution of mM and AuNRs is 400 μg / mL, then it is Example 51.

[0061] Examples 72-133 and Comparative Examples 88-175 This embodiment and comparative example provide a gold nanorod composite Fmoc-L-tyrosine hydrogel, the preparation method of which includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer, PB buffer, or Tris buffer at pH 8.00, vortex and sonicate at 90 °C for 10 min to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine are as follows: Figure 2 As shown, gold nanorod composite Fmoc-L-tyrosine hydrogel was prepared by vortex heating and sonication at 90 ℃ for 10 min. The molar concentrations of PBS buffer, PB buffer, or Tris buffer, the Fmoc-L-tyrosine hydrogel precursor solution, and the mass concentrations of AuNRs aqueous solution are as follows: Figure 2 As shown, the mass concentration of the AuNRs aqueous solution and the molar concentration of the Fmoc-L-tyrosine hydrogel precursor solution represent the concentration in the initial mixed system, not the added concentration. The order of the examples and comparative examples is from front to back, then from bottom to top, and finally from left to right. Examples are those with a mass concentration of AuNRs aqueous solution greater than 0 μg / mL and that form a gel, while the rest are comparative examples.

[0062] Examples 134-210 and Comparative Examples 176-248 This embodiment and comparative example provide a gold nanorod composite Fmoc-L-tyrosine hydrogel, the preparation method of which includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer, PB buffer, or Tris buffer at pH 9.00, vortex and sonicate at 90 °C for 10 min to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine are as follows: Figure 3 As shown, gold nanorod composite Fmoc-L-tyrosine hydrogel was prepared by vortex heating and sonication at 90 ℃ for 10 min. The molar concentrations of PBS buffer, PB buffer, or Tris buffer, the Fmoc-L-tyrosine hydrogel precursor solution, and the mass concentrations of their AuNRs aqueous solutions are as follows: Figure 3 As shown, the mass concentration of the AuNRs aqueous solution and the molar concentration of the Fmoc-L-tyrosine hydrogel precursor solution represent the concentration in the initial mixed system, not the added concentration. The order of the examples and comparative examples is from front to back, then from bottom to top, and finally from left to right. Examples are those with a mass concentration of AuNRs aqueous solution greater than 0 μg / mL and that form a gel, while the rest are comparative examples.

[0063] Examples 211-273 and Comparative Examples 249-335 This embodiment and comparative example provide a gold nanorod composite Fmoc-L-tyrosine hydrogel, the preparation method of which includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer, PB buffer, or Tris buffer at pH 7.00, vortex and sonicate at 90 °C for 10 min to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine are as follows: Figure 4 As shown, gold nanorod composite Fmoc-L-tyrosine hydrogel was prepared by vortex heating and sonication at 90 ℃ for 10 min. The molar concentrations of PBS buffer, PB buffer, or Tris buffer, the Fmoc-L-tyrosine hydrogel precursor solution, and the mass concentrations of their AuNRs aqueous solutions are as follows: Figure 4As shown, the mass concentration of the AuNRs aqueous solution and the molar concentration of the Fmoc-L-tyrosine hydrogel precursor solution represent the concentration in the initial mixed system, not the added concentration. The order of the examples and comparative examples is from front to back, then from bottom to top, and finally from left to right. Examples are those with a mass concentration of AuNRs aqueous solution greater than 0 μg / mL and that form a gel, while the rest are comparative examples.

[0064] Comparative examples 336-485 This comparative example provides a gold nanorod composite Fmoc-L-tyrosine hydrogel, the preparation method of which includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer, PB buffer, or Tris buffer at pH 6.50, vortex and sonicate at 90 °C for 10 min to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine are as follows: Figure 5 As shown, gold nanorod composite Fmoc-L-tyrosine hydrogel was prepared by vortex heating and sonication at 90 ℃ for 10 min. The molar concentrations of PBS buffer, PB buffer, or Tris buffer, the Fmoc-L-tyrosine hydrogel precursor solution, and the mass concentrations of their AuNRs aqueous solutions are as follows: Figure 5 As shown, the mass concentration of AuNRs aqueous solution and the molar concentration of Fmoc-L-tyrosine hydrogel precursor solution represent the concentration in the initial mixed system, not the added concentration; the comparative examples are sorted from front to back, then from bottom to top, and finally from left to right.

[0065] Performance testing methods and results: Testing methods for the properties of gold nanorods: 1. TEM Characterization: The AuNRs aqueous solution prepared in Example 6 was allowed to stand for 24 hours, centrifuged twice for 10 minutes each time, and the precipitate was dispersed in 5 mL of pure water to obtain an aqueous solution of gold nanorods. 8 μL of this solution was drop-cast onto a carbon-coated copper grid and air-dried at room temperature to obtain gold nanorods. The gold nanorods were characterized using a JEM 2100F, and the results are shown in the figure. Figure 6 .

[0066] 2. Ultraviolet characterization: The absorbance of the gold nanorods was measured using a U-3900 ultraviolet spectrophotometer. The results are shown in the figure. Figure 7 and Figure 8 .

[0067] Test method for gold nanorod composite Fmoc-L-tyrosine hydrogel: 1. Transmission electron microscopy test 10 μL of each of the Fmoc-L-tyrosine hydrogel from Comparative Example 36 and the gold nanorod composite Fmoc-L-tyrosine hydrogels from Examples 42 and 45 were directly dropped onto a copper grid. After standing for 1 minute, excess sample was removed by capillary action using filter paper, and the copper grid was then air-dried. The samples were observed using a JEM-2100PLUS transmission electron microscope at an accelerating voltage of 200 kV. The results are shown in the figure. Figures 9-11 .

[0068] 2. Rheological testing: Anton Paar MCR 102 modular intelligent advanced rotational rheometer was used, equipped with a parallel plate fixture with a diameter of 25 mm and a gap of 1 mm.

[0069] (1) Viscosity test: constant temperature (25.00 ± 0.01) ℃, test shear rate 0.01-1000.00 s -1 Interval.

[0070] (2) Amplitude test: constant temperature (25.00 ± 0.01) ℃, constant angular frequency 8.00 rad / s, strain scan range 0.01-100.00%.

[0071] (3) Frequency test: Frequency scan: constant temperature (25.00 ± 0.01) ℃, constant strain 0.10%, angular frequency scan range 6.00-1000.00 rad / s.

[0072] (4) Step strain repair: 11-segment test: strain 0.10% - strain 100.00% - strain 0.10% - strain 100.00% - strain 0.10% - strain 100.00% - strain 0.10% - strain 100.00% - strain 0.10% - strain 100.00% - strain 0.10%, constant temperature (25.00 ± 0.01) ℃.

[0073] Measurement segment 1: Oscillation mode, constant strain and angular frequency, angular frequency 8.00 rad / s, shear strain γ=0.10%, time 120.00s.

[0074] Measurement segment 2: Oscillation mode, constant strain and angular frequency, angular frequency 8.00 rad / s, shear strain γ=100.00%, time 240.00s.

[0075] Measurement segment 3: Oscillation mode, constant strain and angular frequency, angular frequency 8.00 rad / s, shear strain γ=0.10%, time 120.00s.

[0076] Loop to the 11th test segment.

[0077] 3. pH responsiveness test: The pH value of Example 42 was adjusted with 0.2 mmol / L HCl and NaOH solutions, the state of gold nanorod composite Fmoc-L-tyrosine hydrogel was observed, and the precise pH value was measured using a calibrated pH electrode.

[0078] 4. Antibacterial activity assay: Place 500 μL of the prepared hydrogel into an EP tube. After the hydrogel has solidified, take 500 μL of the solution with a concentration of 1×10⁻⁶. 6 A CFU / mL Staphylococcus aureus culture was placed on top of a hydrogel, with a liquid culture medium containing bacteria but without hydrogel serving as a control group. The culture was incubated at 37 ℃ with shaking at 140 r / min for 24 hours. After incubation, 100 μL of the culture was taken out, diluted, and spread onto a plate. The culture dish was then inverted and placed in a 37 ℃ incubator for 18 hours. Afterward, the bacteria were counted and photographed. Among them, Control: liquid culture medium; Gel 1: Fmoc-LY / AuNRs / PBS / pH 15 mM / 0 μg / mL / 50 mM / 7.4; Gel 2: Fmoc-LY / AuNRs / PBS / pH 15 mM / 50 μg / mL / 50 mM / 7.4; Gel 3: Fmoc-LY / AuNRs / PBS / pH 15 mM / 100 μg / mL / 50 mM / 7.4; Gel 4: Fmoc-LY / AuNRs / PBS / pH 15 mM / 200μg / mL / 50 mM / 7.4.

[0079] 5. Photothermal performance measurement method: The hydrogel was prepared into a circle with a diameter of 28 mm and a height of 2 mm. The sample was measured under an 808 nm near-infrared LED light source at a concentration of 15 mW / cm². 2 The hydrogel and AuNRs aqueous solution were irradiated, and the photothermal conversion performance of different samples was tested using a temperature detector, with the temperature recorded every 30 seconds.

[0080] 6. Composite hydrogel injectability test: 2 mL of hydrogel precursor solution was transferred into a 5 mL sterile medical syringe. After the solution solidified to form a gel, a 0.55 mm needle was attached to the syringe. The needle was held perpendicular to the culture dish and kept about 1 cm away. The syringe pump was pushed at a uniform speed to extrude the gel onto the surface of the culture dish. The smoothness of the extrusion process and the morphological characteristics of the extruded gel were observed and photographed.

[0081] Performance testing methods for AuNRs aqueous solution and gold nanorod composite Fmoc-L-tyrosine hydrogel: 1. Ultraviolet characterization: The absorbance of AuNRs aqueous solution and gold nanorod composite Fmoc-L-tyrosine hydrogel was measured using a U-3900 ultraviolet spectrophotometer.

[0082] Performance test results: like Figure 6 As shown, the morphology of gold nanorods was characterized using JEM 2100F and TEM. Figure 6 As can be seen, AuNRs exhibit a slender rod-like structure with blunt, rounded ends, regular shape, uniform size, and good dispersibility, indicating that no aggregation occurred during the preparation process. The size of the gold nanorods was measured using the particle size analysis software Nano Measurer 1.2, yielding an average particle length of 63.73 ± 2.32 nm, an average particle width of 16.17 ± 0.18 nm, and an aspect ratio of approximately 3.94 ± 0.1.

[0083] like Figures 9-11 As shown, Figure 9 It is a Fmoc-L-tyrosine monogel. Figure 10 The composite gel is composed of Fmoc-L-tyrosine@AuNRs at a concentration of 100 μg / mL. Figure 11 The three gels were Fmoc-L-tyrosine@AuNRs composite gels with a concentration of 20 μg / mL, and the molar concentration of Fmoc-L-tyrosine in each gel was 20 mM. Due to limitations in imaging contrast and sample thickness, it was impossible to accurately determine the diameter distribution of nanofibers, the absolute value of porosity, or the specific number of cross-linking nodes using image analysis software. However, through comparative observation, significant differences in the fiber network skeleton among the samples could be clearly identified. Figure 9 The circled area is likely a trace of buffer salt solution, but it does not affect the overall image analysis. The observed area shows a relatively sparse fiber network structure with few inter-fiber cross-links. Large-scale contrasting areas of light and dark are visible, indicating that the pore size is large and the network packing density is low. Figure 10 and Figure 11The number of fibers in the gel increased significantly with increasing AuNRs concentration. The fibers intertwined and entangled, forming a denser three-dimensional network structure. This phenomenon is mainly attributed to the positively charged gold nanorods attracting negatively charged Fmoc-L-tyrosine residues to their surface via electrostatic interactions, creating localized high-concentration regions. This allows the gold nanorods to act as heterogeneous nucleation sites, accelerating the overall fibrosis process and leading to a significant increase in the number of fibers per unit area. The circles under the images indicate AuNRs, clearly showing the selective enrichment of AuNRs. The obvious localized accumulation and entanglement of nanofibers strongly demonstrates that the introduction of AuNRs induced the reconstruction of the gel microstructure. The cationic surfactants on the surface of AuNRs act as multiple physical cross-linking points, forming strong electrostatic interactions with multiple negatively charged Fmoc-L-tyrosine nanofibers. At the same time, the hydrophobic alkyl chains of the ligands on the surface of AuNRs may have hydrophobic interactions with the Fmoc groups and benzene rings. This interaction further stabilizes the adsorption of AuNRs on the fiber surface, thus causing the nanofibers to be tightly entangled locally, forming large fiber cluster-like structural domains. The evolution of this microstructure determines the improvement in the macroscopic properties of the hydrogel. The dense fiber network with large local fibrous clusters provides more elastic load-bearing units. Taking the AuNRs mass concentration in the composite hydrogel as an example, the storage modulus G' of the composite hydrogel in the small strain region is about 4 times higher than that of the single gel. At the same time, the dense network increases the site density of reversible interactions at the fracture interface, and the fiber clusters around the gold nanorods act as reversible cross-linking nodes in the self-healing process, jointly giving the material a significantly improved self-healing recovery rate (from 46% to 85%). Therefore, positively charged gold nanorods, through electrostatic interaction-induced microstructural densification and local enhancement, have successfully achieved synergistic optimization from micro-assembly to macroscopic mechanical and functional properties, providing a clear theoretical basis and experimental support for the design of high-performance self-healing hydrogels.

[0084] like Figure 12 As shown, where Figure 12 (Left) is an image of the Fmoc-L-tyrosine hydrogel sample from Comparative Example 4. Figure 12 (Right) This image shows the gold nanorod composite Fmoc-L-tyrosine hydrogel sample from Example 3. When the Fmoc-L-tyrosine concentration is 10 mmol / L, without the addition of AuNRs, the system only forms a fluid solution and cannot self-support after standing. However, with the addition of AuNRs, a relatively stable hydrogel network with self-supporting properties can be formed in the Fmoc-L-tyrosine concentration of 10 mmol / L. This fundamental difference in macroscopic phenomena indicates that AuNRs should act as a gelation promoter or a gel network crosslinking agent in the gel system, significantly improving the structure of the composite hydrogel network.

[0085] like Figure 13 As shown, compared with the AuNRs aqueous solution prepared in Example 6, the absorbance of the transverse plasmon absorption peak (510 nm) of AuNRs in the gold nanorod composite Fmoc-L-tyrosine hydrogel prepared in Example 42 was significantly enhanced, and the longitudinal plasmon absorption peak showed a significant redshift from 780 nm to 810 nm. This phenomenon is mainly attributed to the spatial confinement effect of the gel network and the change in the local dielectric environment. The three-dimensional gel network effectively suppressed the instantaneous aggregation caused by the Brownian motion of gold nanorods and greatly increased the local effective concentration of gold nanorods, which is manifested as the enhancement of the transverse plasmon absorption peak. At the same time, the negatively charged nanofibers in the Fmoc-L-tyrosine gel formed a local high-refractive-index molecular layer on the surface of the gold nanorods through electrostatic interactions. This layer led to an increase in the effective local refractive index in the long axis direction of the gold nanorods, thereby causing a redshift of the longitudinal plasmon absorption peak. This indicates that the composite hydrogel does not change the inherent properties of AuNRs, but rather provides a stable and biocompatible three-dimensional support environment for AuNRs. At the same time, this effect clearly shows that the optical properties of AuNRs can be actively and precisely controlled by changing the gel matrix material, which lays the foundation for designing sensors based on LSPR wavelength displacement.

[0086] like Figure 14 As shown, all three hydrogels exhibit shear-thinning properties, indicating that the addition of AuNRs does not alter the injectability of Fmoc-LY. The viscosity decreases with increasing shear rate, with a reduction of up to five orders of magnitude, demonstrating good injectability. Higher AuNRs concentrations result in greater gel viscosity, enhancing static stability and enabling the gel to maintain its shape within the syringe. From a high shear rate of 1000 s⁻¹... -1 The viscosity of the single gel is 11 mPa·s. After adding 100 μg / mL of AuNRs, the gel viscosity is 42 mPa·s. After adding 400 μg / mL of AuNRs, the gel viscosity is 115 mPa·s. The addition of AuNRs prevents the viscosity of the gel from becoming too low at high shear rates, effectively preventing excessive diffusion of the gel material.

[0087] like Figure 15As shown, the addition of low-concentration AuNRs aqueous solution enhanced the small-strain region G' of the composite gel by 4 times, while the addition of high-concentration AuNRs enhanced it by 6 times. The critical strain value of the gel network significantly increased with increasing AuNRs aqueous solution content. The critical strain value of the Fmoc-LY monogel was 4%, which increased to 6% after adding 100 μg / mL of AuNRs aqueous solution, and significantly increased to 11% after adding 400 μg / mL of AuNRs aqueous solution. This is mainly attributed to the positively charged gold nanorods inducing fiber network densification through electrostatic interactions, introducing additional electrostatic interactions, and synergistically enhancing hydrogen bonding, hydrophobic interactions, and π-π stacking. The superposition effect of these non-covalent interactions significantly improved the deformability and toughness of the composite gel, enabling it to better resist damage caused by external shear forces.

[0088] like Figure 16 As shown, the Fmoc-LY monogel exhibits the lowest G', indicating a relatively weak three-dimensional network structure with potentially few cross-linking points and insufficient connectivity. The introduction of gold nanorods enhances the G' of the composite gel, suggesting that the nanorods have integrated into the gel network, acting as structural reinforcing agents. The monogel shows G' < G" in the high-frequency region, indicating significant relaxation dynamics and scale inhomogeneity. Correspondingly, its loss factor (tanδ) curve displays a distinct peak within the test window, typically indicating the presence of numerous rapidly relaxing segments or weak cross-linking points within the network. The composite gel shows G' > G" across the entire frequency range, with the tanδ curve becoming flat and its peak disappearing. This result demonstrates the excellent scale-wide stability of the composite gel's network structure. The introduction of gold nanorods not only enhances the macroscopic rigidity of the gel but, more importantly, significantly constrains segment movement at the microscale, locking small-scale units that would otherwise relax freely in the monogel. This constructs a cross-scale stable, highly uniform, and strongly constrained three-dimensional network, achieving a full-frequency elastic solid response.

[0089] like Figure 17As shown, the Fmoc-LY hydrogel's gel network structure was damaged after the first cycle of high-strain shear, and after five cycles, its G' only recovered to 46% of the initial value, indicating that the gel itself has dynamic reversibility, but irreversible damage exists in the gel network under repeated mechanical damage. After adding AuNRs aqueous solution, the self-healing performance of gold nanorod composite Fmoc-L-tyrosine hydrogel was significantly improved. The recovery rate of the composite gel increased to 85% after five cycles when the AuNRs concentration was low, while the recovery rate of the composite gel with high AuNRs concentration reached an excellent 95% after five cycles, indicating that the addition of AuNRs not only improves the mechanical strength of the gel but also enhances its self-healing ability. After adding AuNRs aqueous solution, the composite gel exhibited behavior distinctly different from the monogel. In the initial thixotropic cycles, the recovery rate of the composite gel exceeded 100%; the recovery rate of the low-concentration AuNRs composite hydrogel was >100% in the first three cycles; and the recovery rate of the high-concentration AuNRs composite hydrogel was >100% in the first four cycles. This indicates that higher AuNRs concentrations result in more dynamic cross-linking points, providing stronger network reconstruction capabilities and fatigue resistance, enabling the optimized network structure to withstand more shear failures. Based on these performance improvements, the gold nanorod composite Fmoc-L-tyrosine hydrogel prepared in this invention demonstrates significant advantages in high mechanical strength and excellent self-healing ability, providing an ideal candidate material for the development of injectable tissue engineering scaffolds, wound dressings, and highly durable, self-healing flexible sensors.

[0090] like Figure 18 As shown, different pH values ​​have a significant impact on the mechanical strength of gold nanorod composite Fmoc-L-tyrosine hydrogels. As the pH value increases, the G' of the gel also decreases. It can be observed that when the pH is 9.00, the shear strain value corresponding to tanδ=1 of the composite gel decreases significantly. This phenomenon should be due to the change in the charge state in the system as the pH value increases. Therefore, when the pH value increases, the negative charge carried by Fmoc-LY will also increase, the molecular hydrophilicity will be better, and a certain electrostatic repulsion will be generated, resulting in a weaker gel network structure.

[0091] like Figure 19As shown, the concentration of PBS has a certain impact on the gold nanorod composite Fmoc-L-tyrosine hydrogel. When the concentration of PBS increases, the strength of G' decreases and the range of tanδ also increases. Therefore, the microenvironment inside the gel undergoes a gradual change towards a solution-like state. This phenomenon is closely related to the ionic strength of the solvent. When the concentration of PBS increases, the ionic strength also increases, and the resulting charge shielding effect becomes more significant. After the charge is shielded, the intermolecular forces between Fmoc-LY and AuNRs molecules weaken, the crosslinking points become unstable, resulting in a loose network structure and a decrease in mechanical strength.

[0092] like Figure 20 As shown, different buffer solutions have a certain influence on the gold nanorod composite Fmoc-L-tyrosine hydrogel. The G' of the gel can reach 10 kPa in PBS buffer solution, while the G' strength of the gel weakens and its critical strain value decreases significantly in PB buffer solution. This phenomenon is closely related to the salt ion effect of the two solvents. PBS buffer solution contains a large number of salt ions. When the gold nanorod composite Fmoc-L-tyrosine hydrogel is in a high salt ion environment, it may lead to a weakening of electrostatic interaction and hydrogen bonding, but it may promote the aggregation and association of hydrophobic groups, thereby significantly enhancing the hydrophobic effect.

[0093] like Figure 21As shown, the gold nanorod composite Fmoc-L-tyrosine hydrogel exhibits pH-responsive properties. Adding 0.2 mmol / L NaOH to the gold nanorod composite Fmoc-L-tyrosine hydrogel of Example 42 resulted in a change in the macroscopic structure of the composite gel, with the hydrogel gradually transforming from a gel to a sol. At this point, the pH value of the system was measured to be 9.21. This process is mainly due to the presence of carboxyl and phenolic hydroxyl groups in the Fmoc-L-tyrosine molecule structure within the composite hydrogel, enabling protonation and deprotonation reactions under different pH conditions. Upon addition of NaOH, the solution becomes alkaline, the carboxyl groups are completely deprotonated, and the phenolic hydroxyl groups are partially deprotonated, leading to an increase in the overall negative charge of the molecule. The charge repulsion effect weakens the π-π stacking interaction between Fmoc groups and enhances the hydrophilicity of the molecules, disrupting the hydrophobic interaction balance required to maintain the gel network. Simultaneously, the electrostatic interaction between Fmoc-L-tyrosine and AuNRs also changes with increasing pH, further affecting the stability of the composite system. Therefore, the gel gradually dissociates into a sol. Subsequently, adding 0.2 mmol / L HCl to the sol effectively induced a transition from alkaline to weakly acidic conditions, resulting in a pH of 6.53. Under these conditions, the negative charge in the composite gel system decreased, and the electrostatic repulsion between molecules significantly weakened. Simultaneously, hydrophobic interactions and π-π stacking interactions became the dominant interaction forces, driving molecular assembly and the formation of a three-dimensional network structure, thus achieving a reversible transition from sol to gel. Based on the above analysis, this composite gel system exhibits a clear pH response capability and can achieve reversible sol-gel state regulation within a pH range of 6.53 to 9.21. Therefore, by precisely controlling the pH value of the external environment, the aggregation state, mechanical properties, and microstructure of the composite gel can be directionally adjusted. This clear and reversible pH response mechanism provides an important theoretical basis and control strategy for the design and development of programmable and adaptive smart responsive gel materials.

[0094] like Figure 22 As shown, the control group containing liquid culture medium without hydrogel showed good bacterial growth, while the bacterial group with gold nanorod composite Fmoc-L-tyrosine hydrogel showed a decrease in bacterial colonies. When AuNRs in the gel were ≥100 μg / mL, no bacterial colony growth was observed, indicating a strong antibacterial effect.

[0095] like Figure 23As shown, gels 1, 2, 3, and 4 all contained 50 mM PBS and had a pH of 7.40. Fmoc-LY exhibited a certain antibacterial effect, but the antibacterial rate after 24 hours was only 86.60%. In contrast, the gold nanorod composite Fmoc-L-tyrosine hydrogel with added AuNRs achieved an antibacterial effect of 93.20% at low concentrations, and reached 99.99% when the AuNRs content in the gold nanorod composite Fmoc-L-tyrosine hydrogel was ≥100 μg / mL. Therefore, this gold nanorod composite Fmoc-L-tyrosine hydrogel possesses excellent antibacterial properties.

[0096] like Figure 24 As shown, under 808 nm near-infrared light irradiation, the temperatures of AuNRs aqueous solution, Fmoc-L-tyrosine hydrogel, and gold nanorod composite Fmoc-L-tyrosine hydrogel increased to 47.9 ℃, 19.9 ℃, and 55.8 ℃, respectively, after 900 s. This indicates that the introduction of AuNRs endows the composite hydrogels with excellent photothermal properties, and that the photothermal properties of AuNRs in the gel are superior to those of gold nanorod aqueous solution at the same concentration. This superior photothermal property can be applied to tumor ablation, antibacterial applications, and controlled drug release.

[0097] like Figure 25 As shown, the composite hydrogel can be smoothly extruded from the needle and accurately outlines complex letter shapes on the culture dish. The letter edges are clear, forming a distinct boundary with the background culture dish, and no gel droplets are observed to spread outwards or collapse on the pattern surface. This indicates that the composite hydrogel has good injectability.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. A method for preparing a gold nanorod composite Fmoc-L-tyrosine hydrogel, characterized in that, Includes the following steps: S1. Dissolve Fmoc-L-tyrosine in PBS buffer or PB buffer at pH 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution. S2. Mix AuNRs aqueous solution and Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of AuNRs aqueous solution is 100~400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 15~25 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The molar concentration of the PBS buffer is 50-100 mM, and the molar concentration of the PB buffer is 50 mM.

2. A method for preparing a gold nanorod composite Fmoc-L-tyrosine hydrogel, characterized in that, Includes the following steps: S1. Dissolve Fmoc-L-tyrosine in a buffer solution with a pH of 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution; S2. Mix the AuNRs aqueous solution and the Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of the AuNRs aqueous solution does not exceed 400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 30 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The buffer solution is selected from PBS buffer with a molar concentration of 100 mM.

3. A method for preparing a gold nanorod composite Fmoc-L-tyrosine hydrogel, characterized in that, Includes the following steps: S1. Dissolve Fmoc-L-tyrosine in a buffer solution with a pH of 7.00~9.00, vortex, heat and sonicate to obtain Fmoc-L-tyrosine hydrogel precursor solution; S2. Mix AuNRs aqueous solution and Fmoc-L-tyrosine hydrogel precursor solution. In the initial mixing system, the mass concentration of AuNRs aqueous solution is 100~400 μg / mL and the molar concentration of Fmoc-L-tyrosine is 10 mmol / L. Vortex heating and ultrasonic treatment are performed to obtain gold nanorod composite Fmoc-L-tyrosine hydrogel. The buffer solution is selected from PBS buffer with a molar concentration of 10-50 mM or PB buffer with a molar concentration of 50 mM.

4. The method for preparing the gold nanorod composite Fmoc-L-tyrosine hydrogel according to any one of claims 1 to 3, characterized in that, In S1, the temperature of the heating ultrasound is 80~100 ℃, and the time is 5~15 min.

5. The method for preparing the gold nanorod composite Fmoc-L-tyrosine hydrogel according to any one of claims 1 to 3, characterized in that, In S2, the AuNRs plasma resonance absorption wavelength range is 400-1000 nm, the particle length is 40-80 nm, the particle width is 9-17 nm, and the aspect ratio is 3.8-5.

1. And / or, the temperature of the heating ultrasound is 80~100 ℃, and the time is 5~15 min.

6. The method for preparing the gold nanorod composite Fmoc-L-tyrosine hydrogel according to any one of claims 1 to 3, characterized in that, In S2, the preparation of the AuNRs includes the following steps: Silver nitrate solution, tetrachloroauric acid solution, concentrated hydrochloric acid and hydroquinone were added to an aqueous solution of 1-hexadecyl-N,N-dimethylcyclohexammonium bromide. The reaction was carried out, and sodium borohydride solution was added to continue the reaction. After post-treatment, AuNRs were obtained.

7. The method for preparing the gold nanorod composite Fmoc-L-tyrosine hydrogel as described in claim 6, characterized in that, The molar ratio of 1-hexadecyl-N,N-dimethylcyclohexammonium bromide to silver nitrate, tetrachloroauric acid, hydroquinone, and sodium borohydride is 400~600:1~2:4~6:300~500:2~4.

8. The method for preparing the gold nanorod composite Fmoc-L-tyrosine hydrogel as described in claim 6, characterized in that, The concentrated hydrochloric acid has a mass fraction of 36% to 38%. And / or, the reaction continues until the mixed solution becomes colorless and transparent; And / or, the continued reaction is carried out at a temperature of 30-40 °C for 20-30 hours.

9. A gold nanorod composite Fmoc-L-tyrosine hydrogel, characterized in that, It is prepared by the method described in any one of claims 1 to 8 for the preparation of gold nanorod composite Fmoc-L-tyrosine hydrogel.

10. The application of the gold nanorod composite Fmoc-L-tyrosine hydrogel as described in claim 9 in the preparation of smart wound dressings, targeted drug delivery systems, and implantable bioelectronic devices.

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