Polyoxazoline coated gold nanocage and preparation method thereof
Encapsulating AuNc with PEtOx addresses structural and biocompatibility issues, resulting in AuNc@PEtOx with improved size uniformity and enhanced light-thermal performance for clinical applications.
Patent Information
- Application Number
- CN202510533370.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-26
- Publication Date
- 2025-07-15
AI Technical Summary
The structure and performance of existing gold nanocages are difficult to accurately regulate, and their size is uneven and their porosity is uncontrollable, resulting in poor photothermal performance, and insufficient stability and biocompatibility of existing modifiers, which affects their effectiveness in biomedical applications.
The gold nanocage is coated with poly(2-ethyl-2-oxazoline) and the size, shape and surface chemical properties of the gold nanocage are accurately regulated by the steps of preparing silver nanocubes, gold nanocages and polyoxazoline coatings to form a polyoxazoline-coated gold nanocage.
The prepared AuNc@PEtOx has good photothermal performance and biocompatibility, and can effectively improve the photothermal treatment effect under 808nm laser irradiation, and is suitable for clinical treatment such as orthopedic infection.
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Figure CN120306657A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nanomaterials, and particularly relates to a polyoxazoline-coated gold nanocage and a preparation method thereof. Background Art
[0002] Gold nanoparticles (AuNPs) have become promising nanomaterials in biomedical applications due to their excellent biocompatibility, easy synthesis, and potential for surface ligand functionalization. As a new type of efficient photothermal conversion material among gold nanoparticles, gold nanocages (AuNc) have the structural characteristics of a hollow structure and a porous wall surface.
[0003] Related research shows that AuNc has tunable surface plasmon resonance (SPR) characteristics and can be combined with application methods such as photothermal therapy (PTT). For example, in antibacterial applications, the photothermal effect can be used to inactivate bacteria. When the photothermal agent is exposed to near-infrared light, the gold nanocage generates heat, causing the local temperature to rise, which can effectively damage the bacterial cell membrane, proteins, and other basic structures, resulting in bacterial inactivation or death. In addition, the mild thermal stimulation generated by photothermal therapy has been proven to have a positive impact on bone regeneration. This mild photothermal effect can promote cell proliferation, blood circulation, and stimulate the production of growth factors, thus helping to accelerate the bone healing and regeneration process.
[0004] However, in existing research, it is difficult to precisely control the structure and performance of gold nanocages. The uneven size and uncontrollable porosity of the nanocages easily lead to the shift or broadening of the local surface plasmon resonance (LSPR) peak, making it difficult to match a specific wavelength (such as 808 nm near-infrared light), which in turn results in poor photothermal performance and energy loss. In addition, the surface modifiers of gold nanocages in existing research (such as polyethylene glycol, thiol compounds) may have problems of poor stability and insufficient biocompatibility, which easily lead to in vivo aggregation or immune clearance of gold nanocages.
[0005] Poly(2-ethyl-2-oxazoline) (PEtOx) is a polymer obtained by ring-opening polymerization of 2-ethyl-2-oxazoline monomers. Due to its high hydrophilicity, low immunogenicity, and excellent biocompatibility, it has been widely used in the development of drug delivery carriers, anti-fouling coatings for medical devices, and intelligent biomaterials. Therefore, by encapsulating AuNc in PEtOx to modify its size, shape, surface chemistry, surface charge, and chemical composition, it is expected to further improve the biocompatibility of AuNc. Summary of the Invention
[0006] The object of the present invention is to provide a polyoxazoline-coated gold nanocage based on the shortcomings of the existing technology. The gold nanocage of the present invention has advantages such as good photothermal performance.
[0007] The second technical solution of the present invention is to provide a preparation method of the above-mentioned polyoxazoline-coated gold nanocages.
[0008] For this reason, the first technical solution provided by the present invention is as follows:
[0009] A preparation process of polyoxazoline-coated gold nanocages successively includes the following steps:
[0010] (1) Prepare silver nanocubes (AgNc)
[0011] After heating ethylene glycol to 125 - 150 °C and maintaining it for 45 - 60 min, then add sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution and silver trifluoroacetate solution, and react for 30 - 60 min; after the reaction is completed, cool to room temperature, wash, centrifuge and separate, remove the supernatant, and ultrasonically resuspend the precipitate to obtain an AgNc solution;
[0012] The molar ratio of the sodium hydrosulfide, hydrochloric acid, polyvinylpyrrolidone, and silver trifluoroacetate is 1:(53.3 - 120):
[0013] (2.00 - 3.00):(500 - 700)
[0014] (2) Prepare gold nanocages (AuNc)
[0015] Heat the polyvinylpyrrolidone solution to 85 - 100 °C, add the AgNc solution prepared in the above step (1), and then slowly drop the chloroauric acid solution into the bottle; react for 30 - 60 min while dropping, then cool to room temperature to remove silver chloride, and centrifuge and separate; collect the precipitate, wash the precipitate with deionized water, centrifuge to remove the supernatant, and ultrasonically resuspend the precipitate to obtain an AuNc solution;
[0016] The molar ratio of Ag to polyvinylpyrrolidone in the AgNc solution is 1:(3.99 - 16.1)×10 -4 ;
[0017] (3) Prepare polyoxazoline-coated gold nanocages (AuNc@PEtOx)
[0018] Take the AuNc solution prepared in the above step (2) and add it to the reactor, then add sodium hydroxide solution to adjust the pH of the system to 11, mix evenly, add 3-mercaptopropionic acid, and react in an oil bath at 55 - 60 °C for 3 - 6 h; finally add poly(2-ethyl-2-oxazoline) solution and react overnight; after the reaction is completed, cool to room temperature in a water bath, centrifuge and separate, collect the precipitate, wash and centrifuge to remove the supernatant to obtain AuNc@PEtOx;
[0019] The molar ratio of Au, 3-mercaptopropionic acid, and poly(2-ethyl-2-oxazoline) in the described AuNc solution is 1:(1.3 - 2.4)×10 -2 :(2.2 - 2.7)×10 -4 ;
[0020] Furthermore, the preparation process of the above-mentioned polyoxazoline-coated gold nanocages successively includes the following steps:
[0021] (1) Preparation of AgNc: Add 100 - 150 mL of ethylene glycol to a round-bottom flask and heat to 125 - 150 °C; after 45 - 60 min, successively add sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution to the round-bottom flask, and react for 30 - 60 min; after the reaction is completed, cool to room temperature, add acetone solution to wash the precipitate, and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process twice; resuspend the product with ultrapure water by sonication to obtain an AgNc solution;
[0022] (2) Preparation of AuNc: Add 50 - 100 mL of polyvinylpyrrolidone solution to a round-bottom flask and heat to 85 - 100 °C; add the AgNc solution prepared in the above step (1) to the round-bottom flask, and then slowly add chloroauric acid solution dropwise to the flask; after reacting for 30 - 60 min, record the reaction process with a UV-visible spectrophotometer, and stop adding chloroauric acid solution when the local surface plasmon resonance peak (LSPR) of the reaction solution is about 808 - 815 nm; after the reaction is completed, cool to room temperature in a water bath, add an excess of sodium chloride to remove silver chloride, and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process 2 times; resuspend the precipitate with ultrapure water by sonication to obtain an AuNc solution;
[0023] (3) Preparation of AuNc@PEtOx: Take the AuNc solution prepared in the above step (2) and add it to a conical flask, then add sodium hydroxide solution to the conical flask, mix well, add 3-mercaptopropionic acid, and react in an oil bath at 55 - 60 °C for 3 - 6 h; finally, add poly(2-ethyl-2-oxazoline) solution and react overnight; after the reaction is completed, cool to room temperature in a water bath and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process 2 times to obtain AuNc@PEtOx.
[0024] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the concentration of the sodium hydrosulfide solution in step (1) is 3 - 5 mM, the concentration of the hydrochloric acid solution is 20 - 40 mM, the concentration of the polyvinylpyrrolidone solution is 0.3 - 0.5 mM, and the concentration of the silver trifluoroacetate solution is 250 - 300 mM;
[0025] The solvents of the sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution described in step (1) are all ethylene glycol.
[0026] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the volume ratio of the sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution in step (1) is 1:(8 - 9):(15 - 20):(6 - 7).
[0027] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the hydrochloric acid solution with a concentration of 20 - 40 mM in step (1) is prepared by adding 17 - 33 μL of 38% concentrated hydrochloric acid to 10 mL of ethylene glycol.
[0028] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the concentration of the polyvinylpyrrolidone solution in step (2) is 1 - 2 mg / mL, and the concentration of the chloroauric acid solution is 0.1 - 0.2 mM.
[0029] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the solvents of the polyvinylpyrrolidone solution and chloroauric acid solution in step (2) are both ultrapure water.
[0030] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the dropping rate of the chloroauric acid solution in step (2) is about 0.5 - 1.0 mL / min.
[0031] Furthermore, in the preparation process of the above-mentioned polyoxazoline-coated gold nanocages, the concentration of the sodium hydroxide solution in step (3) is 1.0 - 1.5 mg / mL, the concentration of the poly(2-ethyl-2-oxazoline) solution is 20 mg / mL, the volume ratio of the AuNc solution, sodium hydroxide solution, 3-mercaptopropionic acid, and poly(2-ethyl-2-oxazoline) solution is 1:(5 - 6):(0.005 - 0.006):(5 - 6), and the solvents of the AuNc solution, sodium hydroxide solution, and poly(2-ethyl-2-oxazoline) solution are all ultrapure water.
[0032] Another technical solution of the present invention is to provide a polyoxazoline-coated gold nanocage prepared by the preparation method described in the first technical solution.
[0033] Compared with the prior art, the present invention has the following beneficial effects:
[0034] 1) The present invention provides a simple and efficient method for preparing AuNc@PEtOx. The AuNc@PEtOx prepared by this method has a concentrated size distribution and regular morphology. In addition, the coating of polyoxazoline in the preparation method further modifies the size, structure and surface chemical properties of the gold nanocages, providing a new idea for the development of nanomaterials with specific functions.
[0035] 2) The AuNc@PEtOx prepared by the present invention has good photothermal performance under 808 nm laser irradiation. Clinically, the nanomaterials can be combined with photothermal therapy to further improve the treatment effect, thus overcoming the defects of clinical treatment strategies related to orthopedic infections. Brief Description of the Drawings
[0036] Figure 1 It is the transmission electron microscope (TEM) image of AuNc@PEtOx in Example 1;
[0037] Figure 2 It is the particle size distribution diagram of AuNc@PEtOx in Example 1;
[0038] Figure 3 It is the Zeta potential diagram of AuNc@PEtOx in Example 1;
[0039] Figure 4 It is the photothermal curve of AuNc@PEtOx under near-infrared irradiation (1 W / cm 2 ) in Example 1. Detailed Description of the Invention
[0040] To understand the present invention more deeply, the following will further elaborate on the present invention in combination with the drawings and specific embodiments. These elaborations are intended to further illustrate the features of the present invention rather than to limit the protection scope of the present invention.
[0041] Experimental instruments and models:
[0042] Hitachi HT7700 transmission electron microscope in Japan;
[0043] Brookhaven BI-200SM Zeta potential and particle size analyzer in the United States;
[0044] BOT808 808 nm fiber laser of Xi'an Leize Electronic Technology Co., Ltd. in China
[0045] 326PRO infrared thermal imager of Shanghai Thermovision Electromechanical Technology Co., Ltd. in China
[0046] In the following embodiments:
[0047] The solvents of the sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution described in step (1) are all ethylene glycol.
[0048] The solvents of the polyvinylpyrrolidone solution and chloroauric acid solution described in step (2) are both ultrapure water.
[0049] The solvents of the AuNc solution, sodium hydroxide solution, and poly(2-ethyl-2-oxazoline) solution described in step (3) are all ultrapure water.
[0050] The raw materials involved in the following examples are all commercially available common products or can be prepared by general techniques in the art.
[0051] Example 1
[0052] A polyoxazoline-coated gold nanocage provided in this example is prepared by the following method:
[0053] (1) Preparation of AgNc: Add 100 mL of ethylene glycol to a round-bottom flask and heat it to 150 °C. After 45 min, sequentially add 1.2 mL of sodium hydrosulfide solution (3 mM), 10 mL of hydrochloric acid solution (30 mM), 24 mL of polyvinylpyrrolidone solution (0.36 mM), and 8 mL of silver trifluoroacetate solution (282 mM), and react for 30 min. After completion, cool it to room temperature in a water bath, add acetone solution, and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process twice; resuspend the product ultrasonically with 15 mL of ultrapure water to obtain an AgNc solution (0.15 mol / L).
[0054] (2) Preparation of AuNc: Add 50 mL of polyvinylpyrrolidone solution (1 mg / mL) to a round-bottom flask and heat it to 85 °C. Add 15 mL of the AgNc solution prepared in the above step (1) to the round-bottom flask, and then add chloroauric acid solution (0.1 mM) dropwise at a rate of 0.75 mL / min with a constant flow pump. After reacting for 30 min, record the reaction process with an ultraviolet spectrophotometer, and stop adding the solution when the LSPR peak of the reaction solution is about 808 nm. After the reaction is completed, cool it to room temperature in a water bath, add an excess of sodium chloride, and centrifuge; wash the centrifuged precipitate with deionized water, and then centrifuge to remove the supernatant, and repeat this process 2 times; resuspend the precipitate ultrasonically with 10 mL of ultrapure water to obtain an AuNc solution.
[0055] (3) Preparation of AuNc@PEtOx: Take 4 mL of the AuNc solution prepared in the above step (2) and add it to a conical flask. Add sodium hydroxide solution (1.06 mg / mL) to the conical flask and stir for 10 min to raise the pH value of the solution to 11. Then add 20 μL of 3-mercaptopropionic acid, and place it in an oil bath at 55 °C and stir for 4 h. Finally, add 20 mL of poly(2-ethyl-2-oxazoline) solution (20 mg / mL) and react overnight. After the reaction, cool it to room temperature in a water bath, centrifuge to remove the supernatant and repeat 2 times to obtain AuNc@PEtOx.
[0056] Example 2
[0057] A polyoxazoline-coated gold nanocage provided in this example is prepared by the following method:
[0058] (1) Preparation of AgNc: Add 150 mL of ethylene glycol to a round-bottom flask and heat it to 130 °C. After 50 min, add 1.2 mL of sodium hydrosulfide solution (4 mM), 9.6 mL of hydrochloric acid solution (40 mM), 18 mL of polyvinylpyrrolidone solution (0.4 mM), and 7.2 mL of silver trifluoroacetate solution (250 mM) respectively, and react for 45 min. After the reaction, cool it to room temperature in a water bath, add acetone solution, and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process twice; resuspend the product by ultrasonic treatment with 15 mL of ultrapure water to obtain an AgNc solution (0.12 mol / L).
[0059] (2) Preparation of AuNc: Add 75 mL of polyvinylpyrrolidone solution (1.5 mg / mL) to a round-bottom flask and heat it to 90 °C. Add the AgNc solution prepared in the above step (1) to the round-bottom flask, and then add 22.5 mL of chloroauric acid solution (0.2 mM) dropwise at a rate of 0.5 mL / min with a constant flow pump. After reacting for 45 min, record the reaction process with an ultraviolet spectrophotometer, and stop adding the solution when the LSPR peak of the reaction solution is about 808 nm. After the reaction, cool it to room temperature in a water bath, add an excessive amount of sodium chloride, and centrifuge; wash the centrifuged precipitate with deionized water, and then centrifuge to remove the supernatant, and repeat this process 2 times; resuspend the precipitate by ultrasonic treatment with 10 mL of ultrapure water to obtain an AuNc solution.
[0060] (3) Preparation of AuNc@PEtOx: Take 4 mL of the AuNc solution prepared in the above step (2) and add it to a conical flask. Add sodium hydroxide solution (1.25 mg / mL) to the conical flask and stir for 10 min to raise the pH value of the solution to 11. Then add 21 μL of 3-mercaptopropionic acid, and place it in an oil bath at 60 °C and stir for 3 h. Finally, add 22 mL of poly(2-ethyl-2-oxazoline) solution (20 mg / mL) and react overnight. After the reaction, cool it to room temperature in a water bath, centrifuge to remove the supernatant and repeat 2 times to obtain AuNc@PEtOx.
[0061] Example 3
[0062] A polyoxazoline-coated gold nanocage provided in this example is prepared by the following method:
[0063] (1) Preparation of AgNc: Add 125 mL of ethylene glycol to a round-bottom flask and heat it to 125 °C. After 60 min, add 1.2 mL of sodium hydrosulfide solution (5 mM), 10.8 mL of hydrochloric acid solution (20 mM), 21 mL of polyvinylpyrrolidone solution (0.5 mM), and 8.4 mL of silver trifluoroacetate solution (300 mM) respectively, and react for 60 min. After completion, cool it to room temperature in a water bath, add acetone solution, and centrifuge; wash the centrifuged precipitate with deionized water, centrifuge to remove the supernatant, and repeat this process twice; resuspend the product by ultrasonic treatment with 15 mL of ultrapure water to obtain an AgNc solution (0.17 mol / L).
[0064] (2) Preparation of AuNc: Add 100 mL of polyvinylpyrrolidone solution (2 mg / mL) to a round-bottom flask and heat it to 100 °C. Add the AgNc solution prepared in the above step (1) to the round-bottom flask, and then add 60 mL of chloroauric acid solution (0.1 mM) dropwise at a rate of 1.0 mL / min using a constant flow pump. After reacting for 60 min, record the reaction process with a UV-visible spectrophotometer, and stop adding the solution when the LSPR peak of the reaction solution is about 808 nm. After the reaction is completed, cool it to room temperature in a water bath, add an excess of sodium chloride, and centrifuge; wash the centrifuged precipitate with deionized water, and then centrifuge to remove the supernatant, and repeat this process 2 times; resuspend the precipitate by ultrasonic treatment with 10 mL of ultrapure water to obtain an AuNc solution.
[0065] (3) Preparation of AuNc@PEtOx: Take 4 mL of the AuNc solution prepared in the above step (2) and add it to a conical flask. Add sodium hydroxide solution (1.5 mg / mL) to the conical flask and stir for 10 min to raise the pH value of the solution to 11. Then add 22 μL of 3-mercaptopropionic acid, and place it in an oil bath at 59 °C and stir for 5 h. Finally, add 24 mL of poly(2-ethyl-2-oxazoline) solution (20 mg / mL) and react overnight. After the reaction is completed, cool it to room temperature in a water bath, centrifuge to remove the supernatant and repeat 2 times to obtain AuNc@PEtOx.
[0066] Detection results
[0067] To verify the performance of the AuNc@PEtOx provided in this application, the following gives the detection spectra of the AuNc@PEtOx provided in Example 1. The AuNc@PEtOx in Example 1 is referred to for transmission electron microscopy (TEM) Figure 1 , the particle size distribution diagram is referred to Figure 1 , and the Zeta potential characterization results are referred to Figure 3 ; fromFigure 1 It can be observed that the surface of AuNc@PEtOx is covered with a thin layer of PEtOx, and the AuNc coated with PEtOx presents a regular square structure; from Figure 2 it can be seen that the average particle size of AuNc@PEtOx is about 220±3 nm; from Figure 3 it can be seen that the Zeta potential of AuNc@PEtOx is -13±2 mV, slightly lower than that of the uncoated AuNc, indicating that the surface of AuNc@PEtOx has more charges, suggesting that polyoxazoline is successfully coated on the surface of AuNc.
[0068] The photothermal performance of AuNc@PEtOx was detected by near-infrared irradiation and an infrared thermal imager, and the results are shown in Figure 4 . As can be seen from Figure 4 , when the concentrations of AuNc@PEtOx are 0 μg / mL, 25 μg / mL, 100 μg / mL, 200 μg / mL, and 400 μg / mL respectively, after 10 min of irradiation with an 808 nm laser (1 W / cm 2 ), the increase in the temperature of AuNc@PEtOx shows a concentration dependence. With the adjustment of the nanoparticle concentration, the highest temperature reaches 71 °C, while the temperature change of the control group (deionized water) is not obvious under the same conditions. It can be seen that AuNc@PEtOx has good photothermal performance.
[0069] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. Preparation process of polyoxazoline-coated gold nanocages, characterized in that, The steps are as follows: (1) Preparation of silver nanocubes After heating ethylene glycol to 125-150° C. and maintaining for 45-60 minutes, sodium hydrosulfide solution, hydrochloric acid solution, polyvinyl pyrrolidone solution and silver trifluoroacetate solution are added and reacted for 30-60 minutes; after the reaction is completed, the mixture is cooled to room temperature, washed, centrifuged, the supernatant is removed, and the precipitate is resuspended by ultrasonication to obtain an AgNc solution; The molar ratio of sodium hydrosulfide, hydrochloric acid, polyvinyl pyrrolidone and silver trifluoroacetate is 1:(53.3-120):(2.00-3.00):(500-700); (2) Preparation of gold nanocages Heat the polyvinyl pyrrolidone solution to 85-100° C., add the AgNc solution prepared in step (1) above, and then slowly drop the chloroauric acid solution into the bottle; After reacting for 30-60 minutes while adding dropwise, cool to room temperature to remove silver chloride and centrifuge; The precipitate was collected, washed with deionized water, centrifuged to remove the supernatant, and ultrasonically resuspended the precipitate to obtain the AuNc solution; The molar ratio of Ag to polyvinylpyrrolidone in the described AgNc solution is 1:(3.99 - 16.1)×10 -4 ; (3) Preparation of polyoxazoline-coated gold nanocages The AuNc solution prepared in step (2) above is added to the reactor, and then sodium hydroxide solution is added to adjust the pH of the system to 11. After mixing evenly, 3-mercaptopropionic acid is added, and the reaction is carried out in an oil bath at 55-60° C. for 3-6 hours. Finally, poly(2-ethyl-2-oxazoline) solution is added and the reaction is carried out overnight. After the reaction is completed, the reaction is cooled to room temperature in a water bath, centrifuged, the precipitate is collected, and the supernatant is removed by washing and centrifugation to obtain AuNc@PEtOx. The molar ratio of Au, 3-mercaptopropionic acid, and poly(2-ethyl-2-oxazoline) in the described AuNc solution is 1:(1.3 - 2.4)×10 -2 :(2.2 - 2.7)×10 -4 .
2. The preparation process of the polyoxazoline-coated gold nanocages according to claim 1, characterized in that, The steps are as follows: (1) Preparation of AgNc: 100-150 mL of ethylene glycol was added to a round-bottom flask and heated to 125-150° C.; after 45-60 minutes, sodium hydrosulfide solution, hydrochloric acid solution, polyvinyl pyrrolidone solution and silver trifluoroacetate solution were added to the round-bottom flask in sequence and reacted for 30-60 minutes; after the reaction was completed, the mixture was cooled to room temperature, acetone solution was added to wash the precipitate, and centrifuged; the precipitate obtained by centrifugation was washed with deionized water, the supernatant was removed by centrifugation, and the process was repeated twice; the product was resuspended by ultrasonication with ultrapure water to obtain an AgNc solution; (2) Preparation of AuNc: Add 50-100 mL of polyvinyl pyrrolidone solution to a round-bottom flask and heat to 85-100° C.; Add the AgNc solution prepared in step (1) to the round-bottom flask, and then slowly drop a chloroauric acid solution into the flask; After reacting for 30-60 minutes, record the reaction progress with an ultraviolet spectrophotometer, and stop adding the chloroauric acid solution when the localized surface plasmon resonance peak of the reaction solution is 808-815 nm; After the reaction is completed, cool to room temperature in a water bath, add excess sodium chloride to remove silver chloride, and centrifuge; Wash the precipitate obtained by centrifugation with deionized water, remove the supernatant by centrifugation, and repeat this process twice; Resuspend the precipitate with ultrapure water by ultrasonication to obtain an AuNc solution; (3) Preparation of AuNc@PEtOx: Take the AuNc solution prepared in the above step (2) and add it to a conical flask. Subsequently, add the sodium hydroxide solution to the conical flask. After mixing evenly, add 3-mercaptopropionic acid, and react in an oil bath at 55 - 60 °C for 3 - 6 h; finally, add the poly(2-ethyl-2-oxazoline) solution and react overnight; after the reaction is completed, cool to room temperature in a water bath and centrifuge; wash the precipitate obtained by centrifugation with deionized water, centrifuge to remove the supernatant, and repeat this process 2 times to obtain AuNc@PEtOx.
3. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1, characterized in that, In step (1), the concentration of the sodium hydrosulfide solution is 3 - 5 mM, the concentration of the hydrochloric acid solution is 20 - 40 mM, the concentration of the polyvinylpyrrolidone solution is 0.3 - 0.5 mM, and the concentration of the silver trifluoroacetate solution is 250 - 300 mM; The solvents of the sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution in step (1) are all ethylene glycol.
4. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1 or 2, characterized in that, In step (1), the volume ratio of the sodium hydrosulfide solution, hydrochloric acid solution, polyvinylpyrrolidone solution, and silver trifluoroacetate solution is 1:(8 - 9):(15 - 20):(6 - 7).
5. The preparation process of a polyoxazoline-coated gold nanocage according to claim 4, characterized in that, The hydrochloric acid solution with a concentration of 20 - 40 mM in step (1) is prepared by adding 17 - 33 μL of 38% concentrated hydrochloric acid to 10 mL of ethylene glycol.
6. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1, characterized in that, In step (2), the concentration of the polyvinylpyrrolidone solution is 1 - 2 mg / mL, and the concentration of the chloroauric acid solution is 0.1 - 0.2 mM.
7. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1, characterized in that, The solvents of the polyvinylpyrrolidone solution and chloroauric acid solution in step (2) are both ultrapure water.
8. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1, characterized in that, In step (2), the dropping rate of the chloroauric acid solution is about 0.5 - 1.0 mL / min.
9. The preparation process of a polyoxazoline-coated gold nanocage according to claim 1, characterized in that, In step (3), the concentration of the sodium hydroxide solution is 1.0 - 1.5 mg / mL, the concentration of the poly(2-ethyl-2-oxazoline) solution is 20 mg / mL, the volume ratio of the AuNc solution, sodium hydroxide solution, 3-mercaptopropionic acid, and poly(2-ethyl-2-oxazoline) solution is 1:(5 - 6):(0.005 - 0.006):(5 - 6), and the solvents of the AuNc solution, sodium hydroxide solution, and poly(2-ethyl-2-oxazoline) solution are all ultrapure water.
10. A polyoxazoline-coated gold nanocage, characterized in that, Prepared by the preparation method according to any one of claims 1 - 10.