Bovine serum albumin / silk fibroin composite hydrogel, preparation method and application thereof

Abstract

The application discloses a bovine serum albumin / silk fibroin composite hydrogel, a preparation method and application thereof. The composite hydrogel comprises a first gel network and a second gel network interwoven with the first gel network; the first gel network is formed by a thiol-ene reaction crosslinking between bovine serum albumin and polyethylene glycol dimethacrylate, and the second gel network is formed by an enzyme crosslinking reaction between silk fibroin and peroxidase. The double-network structure composite hydrogel formed by interweaving the first gel network with a network skeleton of bovine serum albumin and the second gel network with a skeleton of silk fibroin not only has good tensile properties and conductivity, but also has good responsiveness and repeatability to continuous changes in temperature / humidity, and has a good application prospect in biological sensing and the like.

Description

Technical Field

[0001] This invention relates to the field of biomaterials technology, and in particular to a bovine serum albumin / silk fibroin composite hydrogel, its preparation method, and its application. Background Technology

[0002] In recent years, flexible electronics technology has developed rapidly and is widely used in wearable electronic devices, electronic skin, soft robots, and self-powered systems. Flexible humidity sensors, as an indispensable part of wearable electronic devices, have received widespread attention due to their potential value in personal healthcare and contactless sensing. Traditional humidity sensors are mostly based on rigid ceramic or Si / SiO2 substrates, and suffer from drawbacks such as low sensitivity, high power consumption, and poor stability. These rigid substrates greatly limit the application of humidity sensors.

[0003] Hydrogels are considered ideal organic humidity-sensitive materials due to their excellent biocompatibility, modulus matching the human body, and low hysteresis. Hydrogels are a class of organic polymer materials with a three-dimensional network structure formed by the cross-linking of hydrophilic polymer chains in a water-rich environment, possessing a wide range of tunable physical and chemical properties. The network structure typically contains strongly hydrophilic groups such as -COOH, -NH2, and -CO-NH. They swell upon contact with water and can absorb hundreds or thousands of times their own weight in water, while retaining a large amount of water without dissolving in water, maintaining good stability and making them excellent water-absorbing materials. For example, patent publication CN116223373A discloses the preparation and application of a hydrogel humidity sensor based on an optical detection method, using hydroxyethyl methacrylate hydrogel as a substrate and developing a simple and controllable hydrogel grating preparation technology. However, existing temperature / humidity sensors suffer from poor biocompatibility and stability. Natural protein materials, such as bovine serum albumin and silk fibroin, avoid the drawbacks of rigid materials, such as poor biocompatibility and poor mechanical properties. They are also non-toxic, harmless, and biodegradable, and have broad application prospects in biomedical materials.

[0004] Therefore, developing a hydrogel-based temperature / humidity sensor with excellent tensile properties, sensitive response to continuous temperature / humidity changes, good stability, and reusability is of great significance in the field of biomedical materials. Summary of the Invention

[0005] To address the aforementioned shortcomings, the present invention aims to provide a bovine serum albumin / silk fibroin composite hydrogel, its preparation method, and its application, thereby solving the problems of low sensitivity, poor mechanical properties, and poor stability of existing temperature / humidity sensors.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a bovine serum albumin / silk fibroin composite hydrogel, comprising a first gel network and a second gel network interwoven with the first gel network; the first gel network is formed by cross-linking of bovine serum albumin and polyethylene glycol dimethacrylate through a thiol-olefin reaction, and the second gel network is formed by enzymatic cross-linking of silk fibroin and peroxidase.

[0008] This invention also provides a method for preparing bovine serum albumin / silk fibroin composite hydrogel, comprising the following steps:

[0009] Bovine serum albumin, polyethylene glycol dimethacrylate, and an alkaline catalyst are dissolved in a first buffer solution to obtain a first precursor solution.

[0010] Silk fibroin and peroxidase were dissolved in a second buffer solution to obtain a second precursor solution;

[0011] After the first precursor solution and the second precursor solution are mixed evenly and allowed to stand, a cross-linking reaction is carried out to obtain bovine serum albumin / silk fibroin composite hydrogel.

[0012] Preferably, the alkaline catalyst is sodium methoxide; the first buffer solution is acetic acid solution; and the second buffer solution is hydrogen peroxide solution.

[0013] Preferably, the method for preparing the first precursor solution is as follows:

[0014] Bovine serum albumin was dissolved in a first buffer solution to obtain a first mixed solution;

[0015] The alkaline catalyst is dissolved in the first buffer solution to obtain the second mixed solution;

[0016] Polyethylene glycol dimethacrylate is dissolved in the second mixed solution to obtain the third mixed solution;

[0017] The first mixed solution is mixed with the third mixed solution to obtain the first precursor solution.

[0018] Preferably, the mass percentage of bovine serum albumin in the first mixed solution is 5% to 40%; the concentration of the alkaline catalyst in the second mixed solution is 0.1M to 5M; the concentration of polyethylene glycol dimethacrylate in the third mixed solution is 0.1M to 5M; the volume ratio of the first mixed solution to the third mixed solution is (1 to 10):(1 to 10); and the pH of the first buffer solution is 5 to 10, and the concentration is 0.1M to 5M.

[0019] Preferably, the method for preparing the second precursor solution is as follows:

[0020] Preparation of silk fibroin solution;

[0021] Preparation of peroxidase solution;

[0022] The silk fibroin solution and the peroxidase solution were mixed evenly to obtain the fourth mixed solution;

[0023] The second buffer solution and the fourth mixed solution are mixed evenly to obtain the second precursor solution.

[0024] Preferably, the concentration of the peroxidase solution is 200 u / mL to 1000 u / mL; the mass fraction of silk fibroin in the fourth mixed solution is 1% to 10%; and the concentration of the second buffer solution is 100 mM to 200 mM.

[0025] Preferably, the volume ratio of the first precursor solution to the second precursor solution is (1-10):(1-10); the temperature of the crosslinking reaction is 1-40°C, the humidity is 1%-100%, and the time is 1-50h.

[0026] The present invention also provides a temperature / humidity sensor comprising the bovine serum albumin / silk fibroin composite hydrogel described above. Preferably, wires are connected to both ends of the bovine serum albumin / silk fibroin composite hydrogel to obtain a temperature / humidity sensor based on the bovine serum albumin / silk fibroin composite hydrogel.

[0027] The present invention also provides an application of the temperature / humidity sensor described above in temperature / humidity sensing and detection, for example, applying a temperature / humidity sensor based on bovine serum albumin / silk fibroin composite hydrogel to gas such as air temperature / humidity detection or to medically monitor respiration to provide an alert for sleep apnea.

[0028] The beneficial effects of this invention are:

[0029] The bovine serum albumin / silk fibroin composite hydrogel provided by this invention exhibits good tensile properties, certain electrical conductivity, and rapid response to temperature and humidity. The preparation method of this invention is simple and easy to manufacture, showing potential for development in the fields of medical devices and biosensors. It can be applied to gas temperature / humidity detection, as well as for medical monitoring of respiration to provide alerts for sleep apnea. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0031] Figure 1 This is a tensile-recovery image of the bovine serum albumin / silk fibroin composite hydrogel provided in Example 1 of the present invention.

[0032] Figure 2 Tensile cyclic stress-strain diagram of bovine serum albumin / silk fibroin composite hydrogel provided in Example 1;

[0033] Figure 3 A schematic diagram of the temperature / humidity sensor structure prepared in Example 4;

[0034] Figure 4 The relative resistance change-humidity curve of the temperature / humidity sensor prepared in Example 4 under different humidity conditions;

[0035] Figure 5 The relative resistance change of the temperature / humidity sensor prepared in Example 4 under different humidity conditions—humidity cycle graph;

[0036] Figure 6 The relative resistance change of the temperature / humidity sensor prepared in Example 4 at different temperatures—temperature curves. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] The bovine serum albumin / silk fibroin composite hydrogel provided in this embodiment of the invention includes a first gel network and a second gel network interwoven with the first gel network; the first gel network is formed by cross-linking of bovine serum albumin and polyethylene glycol dimethacrylate through a thiol-olefin reaction, and the second gel network is formed by cross-linking of silk fibroin and peroxidase through an enzymatic cross-linking reaction.

[0039] The composite hydrogel of this invention is a uniform double-network structure formed by the interweaving of a first gel network with bovine serum albumin (BSA) as the backbone and a second gel network with silk fibroin as the backbone. It not only possesses excellent tensile properties and electrical conductivity but also exhibits good responsiveness and repeatability to continuously changing temperature and humidity. The hydrogel raw materials are bovine serum albumin and silk fibroin, both natural proteins. Compared to inorganic and organic materials, protein materials possess superior mechanical properties, biodegradability, and biocompatibility.

[0040] The method for preparing bovine serum albumin / silk fibroin composite hydrogel provided in this invention includes the following steps:

[0041] S1. Dissolve bovine serum albumin in an acetate buffer solution to obtain a first mixed solution with a bovine serum albumin content of 5% to 40%; wherein the pH of the acetate buffer solution is 5 to 10 and the concentration is 0.1 M to 5 M;

[0042] S2. Dissolve the alkaline catalyst sodium methoxide in an acetic acid buffer solution to obtain a second mixed solution with a sodium methoxide concentration of 0.1M to 5M;

[0043] S3. Dissolve polyethylene glycol dimethacrylate in the second mixed solution to obtain a third mixed solution; wherein the concentration of polyethylene glycol dimethacrylate is 0.1M to 5M;

[0044] S4. Mix the first mixed solution and the third mixed solution at a volume ratio of (1-10):(1-10) to obtain the first precursor solution;

[0045] S5. Prepare silk fibroin solution;

[0046] S6. Prepare peroxidase solutions with a concentration of 200u / mL to 1000u / mL;

[0047] S7. Mix the silk fibroin solution and the peroxidase solution evenly to obtain a fourth mixed solution; wherein the mass fraction of silk fibroin in the fourth mixed solution is 1% to 10%;

[0048] S8. Mix the 100mM to 200mM hydrogen peroxide solution with the fourth mixed solution until homogeneous to obtain the second precursor solution;

[0049] S9. The first precursor solution and the second precursor solution are mixed evenly at a volume ratio of (1-10):(1-10), and then allowed to stand for 1-50 h at a temperature of 1-40℃ and a humidity of 1%-100% to undergo a cross-linking reaction, thereby obtaining bovine serum albumin / silk fibroin composite hydrogel.

[0050] In some preferred embodiments, the silk fibroin solution in step S5 is obtained from silkworm cocoons after degumming, dissolving, and dialysis, specifically as follows:

[0051] Degumming: Take 5g-10g of silkworm cocoons and boil them in a 0.06M NaHCO3 aqueous solution for 30 minutes, repeating three times; then put them in 1-2L of distilled water and boil them for 30 minutes, repeating twice to obtain degummed silk, and place them in a 60℃ oven to dry.

[0052] Dissolving: Take 3-5g of degummed silk and dissolve it in a 9.3mol / L lithium bromide solution at a solid-liquid ratio of 1:6, then place it in a 60℃ oven for 4 hours.

[0053] Dialysis: The dissolved silk solution was dialyzed with deionized water for 48 hours using a dialysis bag with a capacity of 3000-4000 Da (the water was changed every 2 hours) to obtain a silk fibroin solution.

[0054] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] A bovine serum albumin / silk fibroin composite hydrogel is prepared by the following method:

[0057] (1) Dissolve 0.45g of bovine serum albumin powder in 0.5M acetic acid buffer solution with pH=7 to obtain a first mixed solution with a bovine serum albumin mass fraction of 20%.

[0058] (2) Dissolve 1.08g of sodium methoxide in a 0.5M acetic acid buffer solution with pH=7 to obtain a second mixed solution with a sodium methoxide mass fraction of 20%.

[0059] (3) Dissolve 0.225g of polyethylene glycol dimethacrylate in the second mixed solution to obtain a third mixed solution with a polyethylene glycol dimethacrylate mass fraction of 10%.

[0060] (4) The first mixed solution and the third mixed solution are mixed at a volume ratio of 1:1 to obtain the first precursor solution.

[0061] (5) Preparation of silk fibroin solution:

[0062] Degumming: Take 10g of silkworm cocoons and boil them in a 0.06M NaHCO3 aqueous solution for 30 minutes, repeating three times; then put them in 1.5L of distilled water and boil them for 30 minutes, repeating twice to obtain degummed silk, and place them in a 60℃ oven to dry.

[0063] Dissolving: Take 5g of degummed silk and dissolve it in a 9.3mol / L lithium bromide solution at a solid-liquid ratio of 1:6, and then place it in a 60℃ oven for 4 hours.

[0064] Dialysis: The dissolved silk solution was dialyzed with deionized water for 48 hours using a dialysis bag with a capacity of 3000-4000 Da (the water was changed every 2 hours) to obtain a silk fibroin solution.

[0065] (6) Prepare a peroxidase solution with a concentration of 800 u / mL.

[0066] (7) Mix the silk fibroin solution and the peroxidase solution at a volume ratio of 100:1 to obtain the fourth mixed solution.

[0067] (8) The hydrogen peroxide solution with a concentration of 165 mM and the fourth mixed solution are mixed evenly at a volume ratio of 100:1 to obtain the second precursor solution.

[0068] (9) Mix the first precursor solution and the second precursor solution at a volume ratio of 1:1. Then pour the mixture into a mold and place it in a constant temperature and humidity environment (temperature 22℃; humidity 65%) for 12 hours. After taking it out, the bovine serum albumin / silk fibroin composite hydrogel is obtained.

[0069] Example 2

[0070] The difference between this embodiment and embodiment 1 is that in step (9), the first precursor solution and the second precursor solution are mixed evenly at a volume ratio of 1:3.

[0071] The composite hydrogel prepared in this embodiment has similar properties to that in Example 1.

[0072] Example 3

[0073] The difference between this embodiment and Embodiment 1 is that in step (6), a peroxidase solution with a concentration of 1000 u / mL is prepared; and in step (9), the first precursor solution and the second precursor solution are mixed evenly at a volume ratio of 1:3.

[0074] The composite hydrogel prepared in this embodiment has similar properties to that in Example 1.

[0075] Example 4

[0076] A temperature / humidity sensor, such as Figure 3 As shown, the bovine serum albumin / silk fibroin composite hydrogel prepared in Example 1 was prepared by connecting copper wires to both ends.

[0077] Performance testing

[0078] Figure 1 This is a stretch-recovery image of the bovine serum albumin / silk fibroin composite hydrogel provided in Example 1 of the present invention; from Figure 1 It can be seen that the hydrogel can reversibly recover to its original shape after being stretched to a certain extent, indicating that the prepared hydrogel material has good tensile recovery properties.

[0079] Figure 2 The stress-strain diagram of the bovine serum albumin / silk fibroin composite hydrogel after ten tensile cycles provided in Example 1 of this invention; the hydrogel was stretched using a universal testing machine, from... Figure 2 It can be seen that the hydrogel material can still undergo 10 tensile cycles when the tensile strain reaches 600%, indicating that the prepared hydrogel material has good tensile cycle characteristics.

[0080] The composite hydrogel sensor prepared in Example 4 was connected to an LCR meter and then placed in a humidity bottle for testing (room temperature: 25°C). Figure 4The graph shows the relative resistance change of the composite hydrogel sensor under different humidity levels (43%-85%-6%-43%) versus humidity. Figure 4 It can be seen that the resistance change rate of the composite hydrogel sensor is continuous and stable when the humidity changes continuously from 43% to 85% to 6% to 43%, indicating that the prepared composite hydrogel sensor can realize continuous detection under various humidity conditions and has good stability.

[0081] The composite hydrogel sensor prepared in Example 4 was connected to an LCR meter and then placed in a humidity bottle for testing (room temperature: 25°C). Figure 5 The relative resistance change of the composite hydrogel sensor at 43% and 85% humidity – humidity cycle plot; from Figure 5 It can be seen that the resistance change rate of the composite hydrogel sensor remains stable when the humidity is continuously changed between 43% and 85%, indicating that the sensor has a certain degree of cyclic stability.

[0082] The composite hydrogel sensor prepared in Example 4 was connected to an LCR meter and tested using a temperature-controlled stage. Figure 6 The relative resistance change of the composite hydrogel sensor at different temperatures—temperature curves; from Figure 6 It can be seen that the composite hydrogel sensor exhibits certain temperature response performance at different temperatures.

[0083] In summary, the bovine serum albumin / silk fibroin composite hydrogel of the present invention exhibits good tensile properties, certain electrical conductivity, and varying degrees of response to temperature and humidity. Furthermore, its preparation method is simple and easy to manufacture, showing broad promise for applications such as gas humidity detection and medical monitoring of respiration to provide alerts for sleep apnea.

[0084] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0085] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A bovine serum albumin / silk fibroin composite hydrogel, characterized in that, It includes a first gel network and a second gel network interwoven with the first gel network; the first gel network is formed by cross-linking bovine serum albumin and polyethylene glycol dimethacrylate through a thiol-olefin reaction, and the second gel network is formed by enzymatic cross-linking silk fibroin and peroxidase. The preparation method of the bovine serum albumin / silk fibroin composite hydrogel includes the following steps: After the first precursor solution and the second precursor solution are mixed evenly and allowed to stand, a cross-linking reaction is carried out to obtain the bovine serum albumin / silk fibroin composite hydrogel. The preparation method of the first precursor solution is as follows: Bovine serum albumin was dissolved in a first buffer solution to obtain a first mixed solution; The alkaline catalyst is dissolved in the first buffer solution to obtain the second mixed solution; Polyethylene glycol dimethacrylate is dissolved in the second mixed solution to obtain the third mixed solution; The first mixed solution is mixed with the third mixed solution to obtain the first precursor solution; The mass percentage of bovine serum albumin in the first mixed solution is 5%~40%; the concentration of alkaline catalyst in the second mixed solution is 0.1M~5M; the concentration of polyethylene glycol dimethacrylate in the third mixed solution is 0.1M~5M; the volume ratio of the first mixed solution to the third mixed solution is (1~10):(1~10); The preparation method of the second precursor solution is as follows: Preparation of silk fibroin solution; Preparation of peroxidase solution; The silk fibroin solution and the peroxidase solution were mixed evenly to obtain the fourth mixed solution; The hydrogen peroxide solution and the fourth mixed solution were mixed evenly to obtain the second precursor solution; The concentration of the peroxidase solution is 200 u / mL to 1000 u / mL; the mass fraction of silk fibroin in the fourth mixed solution is 1% to 10%; and the concentration of the hydrogen peroxide solution is 100 mM to 200 mM. The volume ratio of the first precursor solution to the second precursor solution is (1~10):(1~10).

2. The bovine serum albumin / silk fibroin composite hydrogel according to claim 1, characterized in that, The alkaline catalyst is sodium methoxide; the first buffer solution is acetic acid solution.

3. The bovine serum albumin / silk fibroin composite hydrogel according to claim 1, characterized in that, The first buffer solution has a pH of 5 to 10 and a concentration of 0.1 M to 5 M.

4. The bovine serum albumin / silk fibroin composite hydrogel according to claim 1, characterized in that, The cross-linking reaction is carried out at a temperature of 1~40℃, a humidity of 1%~100%, and a time of 1~50h.

5. A temperature / humidity sensor, characterized in that, Including the bovine serum albumin / silk fibroin composite hydrogel as described in any one of claims 1-4.

6. The application of the temperature / humidity sensor according to claim 5 in temperature / humidity sensing and detection.

Images