Preparation method of sensing intelligent hydrogel with photo-thermal antibacterial effect

Abstract

The invention discloses a preparation method of sensing intelligent hydrogel with a photo-thermal antibacterial effect. The preparation method comprises the following steps: firstly, preparing reactive poly (N-isopropylacrylamide) microgel and polydopamine nanoparticles; the preparation method comprises the following steps: uniformly mixing poly (N-isopropylacrylamide) microgel, polydopamine nanoparticles and silver nanowires with N-isopropylacrylamide, acrylamide and N, N '-methylene bisacrylamide, adding an initiator and N, N, N', N '-tetramethylethylenediamine, uniformly stirring and mixing with the mixture, and standing for reaction to form the hydrogel. The steps are simple and easy to operate, the prepared hydrogel can be compressed, stretched, bent and twisted, has excellent adhesion performance, self-healing ability, temperature responsiveness, near-infrared responsiveness, oxidation resistance, antibacterial performance and good biocompatibility, can realize sensitive strain sensing, and has wide application prospects. The method has potential application in the fields of bionic skin, novel wound dressings and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogel materials, and in particular to a sensing intelligent hydrogel with photothermal antibacterial effect and a preparation method thereof. Background Art

[0002] Smart hydrogels can significantly change their shape and volume according to environmental stimuli such as temperature, pH, and light. The perfect three-dimensional network structure gives the hydrogel a high water content characteristic. This structure is very similar to soft tissue, which makes it have great application potential in the biomedical field. In recent years, people have had higher demands on the functionality of smart hydrogels, such as sensing performance, in the hope that they can replace traditional electronic devices with poor flexibility and poor biocompatibility. In particular, hydrogel materials with excellent mechanical properties, adhesion properties, self-healing, the ability to sense human movement, and the ability to monitor human physiological status have attracted widespread attention in the fields of electronic skin and tissue engineering.

[0003] Hydrogel sensors can be made by adding conductive nanomaterials such as graphene oxide and carbon nanotubes, or by in-situ forming conductive polymer networks such as polyaniline. However, these hydrogels usually have problems such as low elongation, weak mechanical properties, poor conductivity, low sensing sensitivity and poor stability due to the uneven distribution of doped conductive nanoparticles or poor dispersion of conductive polymers in the hydrogel matrix, which limits their application range.

[0004] For example, Chinese patent document CN 116183071 A discloses a flexible strain sensor based on conductive hydrogel, which is composed of methacrylamide-sodium alginate polymerized hydrogel and graphene oxide doped in the hydrogel. The sensor can monitor the resistance change caused by human body movement, and has the advantages of wide detection range, low detection limit, and good stability. However, the stretchability of the hydrogel is low, and the fracture strain before self-healing is only about 120%, which is not conducive to long-term repeated use, which will seriously limit its practical application.

[0005] For another example, Chinese patent document CN 116606454A discloses a polyacrylamide / sodium alginate / polyaniline composite conductive hydrogel. This patent improves the dispersibility of polyaniline in the hydrogel matrix by means of hydrogen bonding between polydopamine and polyaniline and electrostatic interaction between sodium alginate and polyaniline, thereby improving the sensing sensitivity and stability. However, the adhesion performance and self-healing ability of the hydrogel still need to be improved.

[0006] The sensing hydrogels reported so far generally have problems such as weak adhesion, low stretchability, and inability to self-heal after being broken, which hinder their practical application in wearable strain sensors. In addition, most traditional sensing hydrogels have a single function and cannot adapt to diversified application scenarios. Therefore, it is of great significance to develop a hydrogel material with good mechanical properties, adhesion properties, self-healing ability, sensitive strain sensing, and multifunctionality (such as temperature responsiveness, near-infrared light responsiveness, antioxidant ability, antibacterial effect, etc.). Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide a method for preparing a sensing intelligent hydrogel with photothermal antibacterial effect; the present invention overcomes the shortcomings of poor conductivity and low elongation of current sensing hydrogels by dispersing evenly silver nanowires, and overcomes the problems of weak adhesion and lack of self-healing ability of current sensing hydrogels by dispersing evenly reactive polydopamine nanoparticles, and endows the hydrogel with excellent photothermal antibacterial effect. The sensing intelligent hydrogel prepared by the preparation method of the present invention has good mechanical properties, adhesion properties, self-healing ability, temperature and near-infrared responsiveness, antioxidant capacity, photothermal antibacterial effect and biocompatibility, and can realize sensitive strain sensing.

[0008] To solve the above-mentioned first technical problem, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a sensing intelligent hydrogel with photothermal antibacterial effect comprises the following steps:

[0010] 1) dissolving N-isopropylacrylamide and N,N'-methylenebisacrylamide in deionized water, stirring until completely dissolved, and pumping into a supergravity reactor; after nitrogen deoxygenation for ≥30 minutes, adding an initiator solution, and performing precipitation polymerization reaction under a supergravity environment, thereby preparing a reactive poly(N-isopropylacrylamide) dispersion; immediately placing the poly(N-isopropylacrylamide) dispersion in an ice water bath to terminate the polymerization, storing at -5°C to 5°C, and freeze-drying to obtain a poly(N-isopropylacrylamide) microgel powder for later use;

[0011] 2) dissolving dopamine hydrochloride in deionized water, adjusting the pH to alkaline with ammonia water, and subjecting the mixture to self-polymerization in the air to obtain reactive polydopamine nanoparticles for later use;

[0012] 3) Evenly mix poly(N-isopropylacrylamide) microgel, silver nanowires and polydopamine nanoparticles with N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide and deionized water; deoxygenate with nitrogen for ≥5 min at -5°C to 5°C; then add initiator and N,N,N',N'-tetramethylethylenediamine in sequence, mix quickly, and let stand at room temperature to obtain product sensing intelligent hydrogel.

[0013] Preferably, in step 1), the molar ratio of N,N'-methylenebisacrylamide to N-isopropylacrylamide is 0.5%-5%; the initiator is potassium persulfate or ammonium persulfate; and the molar ratio of the initiator to N-isopropylacrylamide is 1%-4%.

[0014] Preferably, in step 1), the high gravity reactor comprises a high gravity rotating packed bed, a high gravity rotating baffled bed, a high gravity rotating spiral channel, a high gravity rotating disc or a high gravity rotating device.

[0015] Preferably, in step 1), the reaction temperature of the precipitation polymerization reaction is 50 to 90° C., and the reaction time is 2 to 30 min.

[0016] Preferably, in step 2), the weight ratio of dopamine hydrochloride to deionized water is 0.1-0.5:70-150.

[0017] Preferably, in step 2), the alkalinity refers to a pH of 9 to 12.

[0018] Preferably, in step 2), the self-polymerization reaction time is 5 to 60 minutes.

[0019] Preferably, in step 3), the standing time at room temperature is 2 to 48 hours.

[0020] Preferably, in step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator, N,N,N'N'-tetramethylethylenediamine and deionized water is (0.05-1.5):(0.01-0.25):(0.01-1):(15-30):(10-20):(0.003-0.03):(0.5-3):(0.5-2):(70-150).

[0021] More preferably, in step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator, N,N,N'N'-tetramethylethylenediamine and deionized water is (0.45-0.6):(0.05-0.15):(0.02-0.08):(20-25):(13-18):(0.005-0.01):(1-2):(0.7-1):(90-120).

[0022] Preferably, in step 3), the initiator is potassium persulfate or ammonium persulfate.

[0023] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0024] Unless otherwise specified, all raw materials in the present invention can be purchased from the market, and the equipment used in the present invention can adopt conventional equipment in the relevant field or refer to the existing technology in the relevant field.

[0025] Compared with the prior art, the present invention has the following beneficial effects: :

[0026] 1. The steps of the present invention are simple and easy to operate, and the silver nanowires are evenly dispersed in the hydrogel matrix, so that the hydrogel has good sensing sensitivity and stability, and overcomes the disadvantage of low stretchability;

[0027] 2. Uniformly doped reactive polydopamine nanoparticles endow the hydrogel with excellent adhesion, self-healing ability, near-infrared responsiveness, antioxidant capacity and good biocompatibility;

[0028] 3. Using poly (N-isopropylacrylamide) as the main material of the hydrogel gives the hydrogel obvious temperature responsiveness; using reactive poly (N-isopropylacrylamide) microgel as the cross-linking site greatly improves the mechanical strength of the hydrogel;

[0029] 4. The synergistic effect of silver nanowires and polydopamine nanoparticles can achieve excellent photothermal antibacterial effects. This hydrogel material is expected to be used in bionic skin, new wound dressings, flexible soft robots and other material fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Figure 1 is the compression performance of the hydrogel obtained in Example 1;

[0032] Figure 2 is the tensile property of the hydrogel obtained in Example 1;

[0033] Figure 3 The adhesion properties of the hydrogel obtained in Example 1;

[0034] Figure 4 The temperature responsiveness of the hydrogel obtained in Example 1;

[0035] Figure 5 The near infrared responsiveness of the hydrogel obtained in Example 1;

[0036] Figure 6 is the antioxidant capacity of the hydrogel obtained in Example 1;

[0037] Figure 7 The biocompatibility of the hydrogel obtained in Example 1;

[0038] Figure 8 The antibacterial properties of the hydrogels obtained in Example 2, Example 3 and Blank Example 1;

[0039] Fig. 9 The resistive sensing realized by the hydrogel obtained in Example 1;

[0040] Fig.10 The microscopic morphology of the hydrogel obtained in Example 1;

[0041] Fig.11 The microscopic morphology of the hydrogel obtained in Comparative Example 1;

[0042] Fig.12 The microscopic morphology of the hydrogel obtained in Comparative Example 2;

[0043] Fig.13 The bendability of the hydrogel obtained in Comparative Example 1;

[0044] Fig.14 The stretchable properties of the hydrogel obtained in Comparative Example 1. DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0046] Various cross-sectional views of the embodiments disclosed in the present invention are shown in the accompanying drawings. These drawings are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the drawings and the relative sizes and positional relationships between them are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0047] As one aspect of the present invention, a method for preparing a sensing smart hydrogel with photothermal antibacterial effect comprises the following steps:

[0048] 1) dissolving N-isopropylacrylamide and N,N'-methylenebisacrylamide in deionized water, stirring until completely dissolved, and pumping into a supergravity reactor; after nitrogen deoxygenation for ≥30 minutes, adding an initiator solution, and performing precipitation polymerization reaction under a supergravity environment, thereby preparing a reactive poly(N-isopropylacrylamide) dispersion; immediately placing the poly(N-isopropylacrylamide) dispersion in an ice water bath to terminate the polymerization, storing at -5°C to 5°C, and freeze-drying to obtain a poly(N-isopropylacrylamide) microgel powder for later use;

[0049] 2) dissolving dopamine hydrochloride in deionized water, adjusting the pH to alkaline with ammonia water, and subjecting the mixture to self-polymerization in the air to obtain reactive polydopamine nanoparticles for later use;

[0050] 3) Evenly mix poly(N-isopropylacrylamide) microgel, silver nanowires and polydopamine nanoparticles with N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide and deionized water; deoxygenate with nitrogen for ≥5 min at -5°C to 5°C; then add initiator and N,N,N',N'-tetramethylethylenediamine in sequence, mix quickly, and let stand at room temperature to obtain product sensing intelligent hydrogel.

[0051] In the present invention, silver nanowires are one-dimensional nanomaterials with good electrical and thermal properties, excellent flexibility and ductility, and good dispersibility in water. Introducing them into the smart hydrogel matrix can overcome the problem of poor conductivity caused by uneven distribution of nanoparticles, while improving the stretchability and ductility of the hydrogel material. It can also give the hydrogel sensitive strain sensing, which can convert tensile and compressive strains and external photothermal stimulation into electrical signals, and can quickly recover after deformation, with a wide detection range and high detection stability. The introduction of silver nanowires can also give the hydrogel a strong antibacterial ability, and it also has important application value in the field of wound dressings. It is also expected to achieve excellent photothermal sterilization effect by synergizing with polydopamine nanoparticles doped in the hydrogel matrix. Polydopamine has a structure similar to that of marine mussel adhesion protein, which can improve the adhesion, biocompatibility and self-healing ability of the sensing hydrogel to various substrate surfaces. The silver nanowires of the present invention are public technology, and the preparation method of silver nanowires can be obtained by referring to Ind. Eng. Chem. Res. 2019, 58, 20630-20638.

[0052] According to some embodiments of the present invention, in step 1), the molar ratio of N,N'-methylenebisacrylamide to N-isopropylacrylamide is 0.5%-5%; the initiator is potassium persulfate or ammonium persulfate; and the molar ratio of the initiator to N-isopropylacrylamide is 1%-4%.

[0053] According to certain embodiments of the present invention, in step 1), the high gravity reactor comprises a high gravity rotating packed bed, a high gravity rotating baffled bed, a high gravity rotating spiral channel, a high gravity rotating disc or a high gravity rotating device.

[0054] According to some embodiments of the present invention, in step 1), the reaction temperature of the precipitation polymerization reaction is 50-90° C., and the reaction time is 2-30 min.

[0055] According to certain embodiments of the present invention, in step 2), the weight ratio of dopamine hydrochloride to deionized water is 0.1-0.5:70-150.

[0056] According to certain embodiments of the present invention, in step 2), the alkalinity refers to a pH of 9-12.

[0057] According to certain embodiments of the present invention, in step 2), the self-polymerization reaction time is 5 to 60 min; including but not limited to 10 to 60 min, 15 to 60 min, 20 to 60 min, 25 to 60 min, 30 to 60 min, 35 to 60 min, 40 to 60 min, 45 to 60 min, 50 to 60 min, 55 to 60 min, 10 to 55 min, 15 to 55 min, 20 to 55 min, 25 to 55 min, 30 ~55min, 35~55min, 40~55min, 45~55min, 50~55min, 10~50min, 15~50min, 20~50min, 25~50min, 30~50min, 35~50min, 40~50min, 45~50min, 10~40min, 15~40min, 20~40min, 25~40min, 30~40min, or 35~40min.

[0058] According to certain embodiments of the present invention, in step 3), the standing time at room temperature is 2 to 48 hours, including but not limited to 5 to 48 hours, 10 to 48 hours, 15 to 48 hours, 20 to 48 hours, 25 to 48 hours, 30 to 48 hours, 35 to 48 hours, 40 to 48 hours, 5 to 40 hours, 10 to 40 hours, 15 to 40 hours, 20 to 40 hours, 25 to 40 hours, 30 to 40 hours, 35 to 40 hours, 5 to 35 hours, 10 to 35 hours, 15 to 35 hours, 20 to 35 hours, 25 to 35 hours, or 30 to 35 hours.

[0059] According to some embodiments of the present invention, in step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator, N,N,N'N'-tetramethylethylenediamine and deionized water is (0.05-1.5):(0.01-0.25):(0.01-1):(15-30):(10-20):(0.003-0.03):(0.5-3):(0.5-2):(70-150).

[0060] According to certain preferred embodiments of the present invention, in step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator and N,N,N'N'-tetramethylethylenediamine is (0.45-0.6):(0.05-0.15):(0.02-0.08):(20-25):(13-18):(0.005-0.01):(1-2):(0.7-1):(90-120).

[0061] According to certain embodiments of the present invention, in step 3), the initiator is potassium persulfate or ammonium persulfate.

[0062] Example 1

[0063] A method for preparing a sensing intelligent hydrogel with photothermal antibacterial effect comprises the following steps:

[0064] 1) Dissolve 8g N-isopropylacrylamide and 400mg N,N'-methylenebisacrylamide in 490mL deionized water, stir until completely dissolved, and pump into a supergravity reactor. After nitrogen deoxygenation for 30 minutes, add 35mg / mL ammonium persulfate solution and carry out precipitation polymerization under supergravity environment for 5 minutes. Immediately put the obtained reactive poly (N-isopropylacrylamide) microgel dispersion into an ice water bath to terminate the polymerization, and store it at 0°C for subsequent use;

[0065] (2) dissolving 0.3 g of dopamine hydrochloride in 100 mL of deionized water, adjusting the pH to 10 with aqueous ammonia, and self-polymerizing in air for 20 min to obtain reactive polydopamine nanoparticles;

[0066] (3) Take 22 parts of N-isopropylacrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide by weight and dissolve them in 100 parts of deionized water. Then add 0.5 parts of poly(N-isopropylacrylamide) microgel, 0.12 parts of silver nanowires and 0.06 parts of polydopamine nanoparticles and stir to mix evenly. After nitrogen deoxygenation at 0°C for 5 minutes, quickly add 1 part of initiator and 1 part of N,N,N'N'-tetramethylethylenediamine in sequence, mix quickly, and let it stand at room temperature for 24 hours to obtain a hydrogel named Ag. 0.54 P 0.26 M 2.5 P hydrogel.

[0067] Figure 1 is the compression performance of the hydrogel obtained in Example 1;

[0068] Figure 2 is the tensile property of the hydrogel obtained in Example 1;

[0069] Figure 3 The adhesion properties of the hydrogel obtained in Example 1;

[0070] Figure 4 The temperature responsiveness of the hydrogel obtained in Example 1;

[0071] Figure 5 The near infrared responsiveness of the hydrogel obtained in Example 1;

[0072] Figure 6 is the antioxidant capacity of the hydrogel obtained in Example 1;

[0073] Figure 7 The biocompatibility of the hydrogel obtained in Example 1;

[0074] Fig. 9 The resistive sensing realized by the hydrogel obtained in Example 1;

[0075] Fig.10 This is the microscopic morphology of the hydrogel obtained in Example 1.

[0076] Example 2

[0077] A method for preparing a sensing intelligent hydrogel with photothermal antibacterial effect comprises the following steps:

[0078] Compared with Example 1, the difference lies in the amount of polydopamine nanoparticles added. The specific steps are:

[0079] By weight, 22 parts of N-isopropylacrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide were dissolved in 100 parts of deionized water. Then 0.5 parts of poly(N-isopropylacrylamide) microgel, 0.12 parts of silver nanowires and 0.03 parts of polydopamine nanoparticles were added and stirred to mix evenly. After nitrogen deoxygenation at 0°C for 5 minutes, 1 part of initiator and 1 part of N,N,N'N'-tetramethylethylenediamine were quickly added in sequence, and after rapid mixing, the reaction was allowed to stand at room temperature for 24 hours to obtain a hydrogel named Ag. 0.54 P 0.13 M 2.5 P hydrogel.

[0080] The antibacterial properties of the hydrogel obtained in this example are shown in Figure 8 shown.

[0081] Example 3

[0082] A method for preparing a sensing intelligent hydrogel with photothermal antibacterial effect comprises the following steps:

[0083] Compared with Example 1, the difference lies in the amount of silver nanowires and polydopamine nanoparticles added. The specific steps are:

[0084] By weight, 22 parts of N-isopropylacrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide were dissolved in 100 parts of deionized water. Then 0.5 parts of poly(N-isopropylacrylamide) microgel, 0.06 parts of silver nanowires and 0.03 parts of polydopamine nanoparticles were added and stirred to mix evenly. After nitrogen deoxygenation at 0°C for 5 minutes, 1 part of initiator and 1 part of N,N,N',N'-tetramethylethylenediamine were quickly added in sequence, mixed quickly, and allowed to react at room temperature for 24 hours to obtain a hydrogel named Ag. 0.27 P 0.13 M 2.5 P hydrogel.

[0085] The antibacterial properties of the hydrogel obtained in this example are shown in Figure 8 shown.

[0086] Blank example 1

[0087] Compared with Example 1, the difference is that no poly(N-isopropylacrylamide) microgel, silver nanowires and polydopamine nanoparticles are added, and only poly(N-isopropylacrylamide-co-acrylamide) hydrogel is prepared. The specific steps are:

[0088] By weight, 22 parts of N-isopropyl acrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide were dissolved in 100 parts of deionized water and stirred to mix evenly. After nitrogen deoxygenation for 5 minutes, 1 part of initiator and 1 part of N,N,N',N'-tetramethylethylenediamine were quickly added in sequence, mixed quickly, and allowed to react at room temperature for 24 hours to obtain a hydrogel named PNAM hydrogel.

[0089] The antibacterial properties of the hydrogel obtained in this blank example are shown in Figure 8 shown.

[0090] Comparative Example 1

[0091] Compared with Example 1, the difference is that silver nanowires and polydopamine nanoparticles are not added, and the specific steps are:

[0092] By weight, 22 parts of N-isopropylacrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide were dissolved in 100 parts of deionized water. Then 0.5 parts of poly(N-isopropylacrylamide) microgel were added and stirred to mix evenly. After nitrogen deoxygenation at 0°C for 5 minutes, 1 part of initiator and 1 part of N,N,N',N'-tetramethylethylenediamine were quickly added in sequence, mixed quickly, and allowed to react at room temperature for 24 hours to obtain a hydrogel named MGs. 5min -PNAM hydrogel.

[0093] Fig.11 The microscopic morphology of the hydrogel obtained in Comparative Example 1;

[0094] Fig.13 The bendability of the hydrogel obtained in Comparative Example 1;

[0095] Fig.14 The stretchable properties of the hydrogel obtained in Comparative Example 1.

[0096] It can be seen that when PNAM hydrogel is compounded with reactive PNIPAM microgel, the microgel can be used as a nano-crosslinking site to construct a nanostructure, which improves the elasticity of the hydrogel and enables the hydrogel to withstand high deformation. However, the hydrogel does not have the properties of near-infrared light response, antibacterial, adhesion, self-healing and strain sensing.

[0097] Comparative Example 2

[0098] Compared with Comparative Example 2, the difference is that the reactivity of poly(N-isopropylacrylamide) microgel is different. The specific steps are:

[0099] (1) Dissolve 8 g of N-isopropylacrylamide and 400 mg of N,N'-methylenebisacrylamide in 490 mL of deionized water, stir until completely dissolved, and pump into a high-gravity reactor. After nitrogen deoxygenation for 30 min, add 35 mg / mL of ammonium persulfate solution and carry out precipitation polymerization under high-gravity environment for 6 h. Immediately put the obtained reactive poly (N-isopropylacrylamide) microgel dispersion into an ice water bath to terminate the polymerization, and store it at 0 °C for subsequent use;

[0100] (2) Take 22 parts of N-isopropylacrylamide, 15 parts of acrylamide and 0.008 parts of N,N'-methylenebisacrylamide by weight and dissolve them in 100 parts of deionized water. Then add 0.5 parts of poly(N-isopropylacrylamide) microgel and stir to mix evenly. After nitrogen deoxygenation at 0°C for 5 minutes, quickly add 1 part of initiator and 1 part of N,N,N',N'-tetramethylethylenediamine in sequence, mix quickly, and let it react at room temperature for 24 hours to obtain a hydrogel, which is named MGs-PNAM hydrogel.

[0101] Fig.12 The microscopic morphology of the hydrogel obtained in Comparative Example 2;

[0102] It can be seen from this that PNIPAM microgels without reactive activity cannot be used as nano-crosslinkers to construct the nanostructure of hydrogels. The microgels are only doped in the pores of the three-dimensional network of hydrogels and cannot achieve the goal of improving the mechanical properties of PNAM hydrogels.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing a sensing smart hydrogel with photothermal antibacterial effect, characterized in that: The steps include: 1) dissolving N-isopropylacrylamide and N,N'-methylenebisacrylamide in deionized water, stirring until completely dissolved, and pumping into a supergravity reactor; after nitrogen deoxygenation for ≥30 minutes, adding an initiator solution, and performing precipitation polymerization reaction under a supergravity environment, thereby preparing a reactive poly(N-isopropylacrylamide) dispersion; immediately placing the poly(N-isopropylacrylamide) dispersion in an ice water bath to terminate the polymerization, storing at -5°C to 5°C, and freeze-drying to obtain a poly(N-isopropylacrylamide) microgel powder for later use; 2) dissolving dopamine hydrochloride in deionized water, adjusting the pH to alkaline with ammonia water, and subjecting the mixture to self-polymerization in the air to obtain reactive polydopamine nanoparticles for later use; 3) Evenly mix poly(N-isopropylacrylamide) microgel, silver nanowires and polydopamine nanoparticles with N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide and deionized water; deoxygenate with nitrogen for ≥5 min at -5°C to 5°C; then add initiator and N,N,N',N'-tetramethylethylenediamine in sequence, mix quickly, and let stand at room temperature to obtain product sensing intelligent hydrogel.

2. The preparation method according to claim 1, characterized in that: In step 1), the molar ratio of N,N'-methylenebisacrylamide to N-isopropylacrylamide is 0.5%-5%; the initiator is potassium persulfate or ammonium persulfate; the molar ratio of the initiator to N-isopropylacrylamide is 1%-4%.

3. The preparation method according to claim 1, characterized in that: In step 1), the high gravity reactor comprises a high gravity rotating packed bed, a high gravity rotating baffled bed, a high gravity rotating spiral channel, a high gravity rotating disc or a high gravity rotating device.

4. The preparation method according to claim 1, characterized in that: In step 1), the reaction temperature of the precipitation polymerization reaction is 50-90° C., and the reaction time is 2-30 min.

5. The preparation method according to claim 1, characterized in that: In step 2), the weight ratio of dopamine hydrochloride to deionized water is 0.1-0.5:70-150.

6. The preparation method according to claim 1, characterized in that: In step 2), the alkalinity refers to a pH of 9 to 12; preferably, in step 2), the self-polymerization reaction time is 5 to 60 minutes.

7. The preparation method according to claim 1, characterized in that: In step 3), the standing time at room temperature is 2 to 48 hours.

8. The preparation method according to claim 1, characterized in that: In step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator, N,N,N'N'-tetramethylethylenediamine and deionized water is (0.05-1.5):(0.01-0.25):(0.01-1):(15-30):(10-20):(0.003-0.03):(0.5-3):(0.5-2):(70-150).

9. The preparation method according to claim 8, characterized in that: In step 3), the weight ratio of the poly(N-isopropylacrylamide) microgel, silver nanowires, polydopamine nanoparticles, N-isopropylacrylamide, acrylamide, N,N'-methylenebisacrylamide, initiator, N,N,N'N'-tetramethylethylenediamine and deionized water is (0.45-0.6):(0.05-0.15):(0.02-0.08):(20-25):(13-18):(0.005-0.01):(1-2):(0.7-1):(90-120).

10. The preparation method according to claim 1, characterized in that: In step 3), the initiator is potassium persulfate or ammonium persulfate.

Images