A water-resistant biocompatible hydrogel and its preparation method and application

Abstract

The application discloses a kind of water-resistant biocompatible hydrogel, including the following weight parts of raw materials: hydroxypropyl cellulose 5-25 parts, polyacrylamide 2.5-15 parts and trihydroxyethyl methyl ketone acid ammonium 25-75 parts;Preparation method specifically includes the following steps: (1) weighing each raw material;(2) preparation hydroxypropyl cellulose / polyacrylamide solution;(3) static defoaming, freeze;(4) preparation trihydroxyethyl methyl ketone acid ammonium solution;(5) add hydroxypropyl cellulose / polyacrylamide frozen product, static reaction, flush, obtain immediately.The hydrogel of the application not only has excellent mechanical properties, but also has biocompatibility, non-toxicity, green environmental protection, can be used directly, high flexibility, high conductivity, fatigue resistance, anti-swelling, water resistance and other advantages, and the preparation process is simple, the investment cost is low, the practicality is strong, and it is easy to realize industrialization promotion.

Description

Technical Field

[0001] This invention relates to the field of conductive hydrogel technology, and more specifically to a water-resistant, biocompatible hydrogel, its preparation method, and its application. Background Technology

[0002] Conductive hydrogel sensors, which can convert various deformations and / or movements into electrical signals, have attracted much attention in fields such as wearable devices, biomedical applications, electronic skin, flexible supercapacitors, and soft robots.

[0003] The conductivity of conductive hydrogels is achieved by introducing conductive components into the hydrogel. Typical conductive components are mainly classified into four categories: nanoscale metal components (gold nanowires, silver nanowires, liquid gallium, and indium), nanoscale carbon conductors (single / multi-walled carbon nanotubes, graphene, MXene, and carbon), conductive polymers (polyaniline, polythiophene, and 23PEDOT:PSS), and inorganic salts. However, these conductive components have the following problems.

[0004] First, the inherent rigidity of nanoscale metal and carbon components generates interfacial stress that frictionally interacts with the soft hydrogel, thus reducing its mechanical properties. Therefore, their amount in the hydrogel must be reduced; however, this reduction leads to a decrease in the hydrogel's conductivity. Another problem is that the metal and carbon components require pre-modification with hydrophilic samples because they have poor miscibility with water and are difficult to disperse well in solvents.

[0005] Secondly, hydrogels containing conductive polyaniline and polythiophene polymers typically involve complex preparation processes (monomer polymerization to obtain conductive polymers, washing away unreacted compounds and byproducts, energy consumption, etc.), the addition of toxic crosslinking agents, and uneven distribution of conductive polymers. Although the conductive polymer PEDOT:PSS can impart conductivity to hydrogels, improve mechanical properties and biocompatibility, its high cost makes mass production of hydrogels difficult to achieve.

[0006] The third problem is that when using inorganic salts as conductors, hydrogels typically achieve conductivity by immersing freeze-dried hydrogels in an inorganic salt solution. However, the low concentration of inorganic salt ions in the hydrogel results in low electrical conductivity. Furthermore, this method makes it difficult to obtain hydrogels with both high mechanical properties and high conductivity; if the conductivity is high, the mechanical properties of the hydrogel will significantly decrease. In addition, these hydrogels have poor elasticity and flexibility, making them unsuitable for use as strain sensors.

[0007] The fourth problem is that the use of organic components to pre-modify and / or pre-disperse conductive components often leads to the non-biocompatibility of hydrogels.

[0008] The fifth problem is that most hydrogels are prone to unavoidable swelling or degradation in liquid environments, which will jeopardize the stability and practical applications of hydrogels.

[0009] Therefore, how to develop a hydrogel that can simultaneously meet the requirements of high conductivity, high mechanical properties, anti-swelling ability, water resistance, and other high performance while simplifying the preparation process is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0010] In view of this, the purpose of the present invention is to provide a water-resistant, biocompatible hydrogel, its preparation method and application, so as to overcome the shortcomings of the prior art.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A water-resistant, biocompatible hydrogel comprises the following raw materials in parts by weight: 5-25 parts hydroxypropyl cellulose, 2.5-15 parts polyacrylamide, and 25-75 parts trihydroxyethylmethylpyruvate ammonium.

[0013] The preferred composition is: 25 parts hydroxypropyl cellulose, 5 parts polyacrylamide, and 50 parts trihydroxyethyl methyl pyruvate.

[0014] Alternatively, 25 parts hydroxypropyl cellulose, 15 parts polyacrylamide, and 50 parts trihydroxyethyl methyl pyruvate ammonium.

[0015] Alternatively, 25 parts hydroxypropyl cellulose, 15 parts polyacrylamide, and 75 parts trihydroxyethyl methyl pyruvate ammonium.

[0016] In this invention, hydroxypropyl cellulose is not only water-soluble, but also biocompatible and biodegradable. Moreover, it contains a large number of hydroxyl groups, which can form hydrogen bonds with the amine groups in polyacrylamide, thereby enhancing the mechanical properties of the gel.

[0017] Polyacrylamide is water-soluble and biocompatible, and the amine groups on its molecular chain can form hydrogen bonds with the large number of hydroxyl groups present in hydroxypropyl cellulose, thereby enhancing the mechanical properties of the gel.

[0018] The hydroxyl and carbonyl oxygen atoms in ammonium trihydroxyethylmethylpyruvate can form hydrogen bonds with the amine groups on the polyacrylamide molecular chain and the numerous hydroxyl groups present in hydroxypropyl cellulose, thus enhancing the mechanical properties of the gel. Furthermore, ammonium trihydroxyethylmethylpyruvate can also increase the electrical conductivity of the gel.

[0019] A method for preparing a water-resistant, biocompatible hydrogel specifically includes the following steps:

[0020] (1) Weigh each raw material according to the above-mentioned water-resistant and biocompatible hydrogel weight parts;

[0021] (2) Add hydroxypropyl cellulose and polyacrylamide to deionized water and stir to obtain a hydroxypropyl cellulose / polyacrylamide solution;

[0022] (3) The hydroxypropyl cellulose / polyacrylamide solution was allowed to stand to remove bubbles and then frozen to obtain frozen hydroxypropyl cellulose / polyacrylamide product;

[0023] (4) Add trihydroxyethyl methyl pyruvate ammonium to deionized water and stir until homogeneous to obtain trihydroxyethyl methyl pyruvate ammonium solution;

[0024] (5) Add the hydroxypropyl cellulose / polyacrylamide frozen product to the trihydroxyethyl methyl pyruvate ammonium solution, let it stand to react, and rinse to obtain a water-resistant and biocompatible hydrogel.

[0025] Furthermore, in step (2) above, the stirring temperature is 15-40℃ and the stirring time is 0.5-1h; in the hydroxypropyl cellulose / polyacrylamide solution, the mass concentration of hydroxypropyl cellulose is 1%-5%, preferably 5%; in the hydroxypropyl cellulose / polyacrylamide solution, the mass concentration of polyacrylamide is 0.5%-3%, preferably 1%.

[0026] Furthermore, in step (3) above, the time for standing and degassing is 0.5-1h; the freezing temperature is -20℃ and the time is 2-6h.

[0027] The further beneficial effect of the above-mentioned method is that, through static degassing, air bubbles in the hydroxypropyl cellulose / polyacrylamide solution can be removed, preventing these air bubbles from remaining in the frozen hydroxypropyl cellulose / polyacrylamide product during freezing, thereby reducing the mechanical properties of the hydrogel. Simultaneously, freezing facilitates the formation of a gel in the frozen hydroxypropyl cellulose / polyacrylamide product in the trihydroxyethylmethylpyruvate ammonium solution.

[0028] Furthermore, in step (4) above, the mass concentration of the trihydroxyethyl methylpyruvate ammonium solution is 5%-15%.

[0029] Furthermore, in step (5) above, the reaction time is 0.5-1h.

[0030] This invention also claims the application of a water-resistant, biocompatible hydrogel prepared by the above-described method in the preparation of wearable flexible sensors, conductive materials, or smart screen touchscreen materials.

[0031] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. This invention provides a novel biocompatible hydroxypropyl cellulose / polyacrylamide / trihydroxyethyl methyl pyruvate ammonium hydrogel, which not only has excellent mechanical properties, but also has advantages such as biocompatibility, non-toxicity, green environmental protection, direct use, high flexibility, high electrical conductivity, fatigue resistance, swelling resistance, and water resistance.

[0033] 2. The hydrogel of this invention has excellent anti-swelling and water resistance. Its mechanical properties remain almost unchanged after being soaked in water for three months, and it can be used for a long time in complex and harsh environments.

[0034] 3. The hydrogel of this invention uses ammonium trihydroxyethyl methylpyruvate, which does not require a complex polymerization reaction like traditional conductive polymer hydrogels, nor does it require the use of toxic volatile organic reagents. Therefore, it is not only simple in process and low in investment cost, but also non-toxic and biocompatible, with a wide range of applications.

[0035] 4. The hydrogel of this invention is different from hydrogels prepared with inorganic salt conductive components (which reduce the conductivity or elasticity and flexibility of the hydrogel). This hydrogel is soft and easily responds to various deformations or movements, which is beneficial for converting various deformations or movements into electrical signals.

[0036] 5. Compared with traditional preparation processes, the preparation process of the hydrogel of this invention is simple, the product does not require cleaning or purification, there is no pollutant emission, no special equipment is required, and no chemical reaction is involved, thus solving the problem of the complexity of traditional hydrogel preparation processes; moreover, the investment cost is low, the practicality is strong, and it is easy to achieve industrial promotion. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a hydrogel strain sensor.

[0038] Figure 2 This is the electrical output signal from the finger;

[0039] Figure 3 It provides electrical output signals for the wrist, elbow, and knee joints. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] A water-resistant, biocompatible hydrogel comprising the following raw materials by weight: 25g hydroxypropyl cellulose, 5g polyacrylamide, and 50g trihydroxyethylmethylpyruvate.

[0043] The preparation method of the above-mentioned water-resistant and biocompatible hydrogel specifically includes the following steps:

[0044] (1) Weigh each raw material according to the weight of the above water-resistant and biocompatible hydrogel;

[0045] (2) Add 25g of hydroxypropyl cellulose and 5g of polyacrylamide to 500g of deionized water and stir at 30℃ for 1h to obtain hydroxypropyl cellulose / polyacrylamide solutions with mass concentrations of 5% and 1% respectively.

[0046] (3) Let the hydroxypropyl cellulose / polyacrylamide solution stand for 0.5 h to degas, then pour it into a standard dumbbell-shaped template and a square template, put it in a refrigerator, and freeze it at -20℃ for 2 h to obtain frozen hydroxypropyl cellulose / polyacrylamide.

[0047] (4) Add 50g of trihydroxyethyl methyl pyruvate ammonium to 500g of deionized water and stir until homogeneous to obtain a 10% trihydroxyethyl methyl pyruvate ammonium solution.

[0048] (5) Add the hydroxypropyl cellulose / polyacrylamide frozen product to the trihydroxyethyl methyl pyruvate ammonium solution, let it stand for 0.5 h, and rinse the surface solution with deionized water to obtain a water-resistant and biocompatible hydrogel.

[0049] Example 2

[0050] A water-resistant, biocompatible hydrogel comprising the following raw materials by weight: 25g hydroxypropyl cellulose, 15g polyacrylamide, and 50g trihydroxyethylmethylpyruvate.

[0051] The preparation method of the above-mentioned water-resistant and biocompatible hydrogel specifically includes the following steps:

[0052] (1) Weigh each raw material according to the weight of the above water-resistant and biocompatible hydrogel;

[0053] (2) Add 25g of hydroxypropyl cellulose and 15g of polyacrylamide to 500g of deionized water and stir at 30℃ for 1h to obtain hydroxypropyl cellulose / polyacrylamide solutions with mass concentrations of 5% and 3% respectively.

[0054] (3) Let the hydroxypropyl cellulose / polyacrylamide solution stand for 0.5 h to degas, then pour it into a standard dumbbell-shaped template and a square template, put it in a refrigerator, and freeze it at -20℃ for 2 h to obtain frozen hydroxypropyl cellulose / polyacrylamide.

[0055] (4) Add 50g of trihydroxyethyl methyl pyruvate ammonium to 500g of deionized water and stir until homogeneous to obtain a 10% trihydroxyethyl methyl pyruvate ammonium solution.

[0056] (5) Add the hydroxypropyl cellulose / polyacrylamide frozen product to the trihydroxyethyl methyl pyruvate ammonium solution, let it stand for 0.5 h, and rinse the surface solution with deionized water to obtain a water-resistant and biocompatible hydrogel.

[0057] Example 3

[0058] A water-resistant, biocompatible hydrogel comprising the following raw materials by weight: 25g hydroxypropyl cellulose, 15g polyacrylamide, and 75g trihydroxyethylmethylpyruvate.

[0059] The preparation method of the above-mentioned water-resistant and biocompatible hydrogel specifically includes the following steps:

[0060] (1) Weigh each raw material according to the weight of the above water-resistant and biocompatible hydrogel;

[0061] (2) Add 25g of hydroxypropyl cellulose and 15g of polyacrylamide to 500g of deionized water and stir at 30℃ for 1h to obtain hydroxypropyl cellulose / polyacrylamide solutions with mass concentrations of 5% and 3% respectively.

[0062] (3) Let the hydroxypropyl cellulose / polyacrylamide solution stand for 0.5 h to degas, then pour it into a standard dumbbell-shaped template and a square template, put it in a refrigerator, and freeze it at -20℃ for 2 h to obtain frozen hydroxypropyl cellulose / polyacrylamide.

[0063] (4) Add 75g of ammonium trihydroxyethyl methyl pyruvate to 500g of deionized water and stir until homogeneous to obtain a 15% ammonium trihydroxyethyl methyl pyruvate solution.

[0064] (5) Add the hydroxypropyl cellulose / polyacrylamide frozen product to the trihydroxyethyl methyl pyruvate ammonium solution, let it stand for 0.5 h, and rinse the surface solution with deionized water to obtain a water-resistant and biocompatible hydrogel.

[0065] Performance testing

[0066] 1. Strain sensor test

[0067] The water-resistant, biocompatible hydrogel prepared in Example 2 was cut into a long strip (72mm × 12mm × 1.3mm), and both ends were covered with copper foil strips. The copper foil strips were then connected to conductive copper wires to assemble a hydrogel strain sensor, as shown in the schematic diagram. Figure 1 As shown.

[0068] Hydrogel strain sensors were fixed to the fingers, wrists, elbows, and knees, respectively, to detect the electrical output signals of these joints. The results are as follows: Figure 2-3 As shown.

[0069] Depend on Figure 2-3 It is understood that the water-resistant and biocompatible hydrogel of the present invention can be used to prepare wearable sensors.

[0070] 2. Conductivity test

[0071] The water-resistant biocompatible hydrogel prepared in Example 2 was found to have a conductivity of 5.7 S / cm, which is 27 times that of the biocompatible hydrogel with the highest conductivity to date.

[0072] This experiment demonstrates that the water-resistant, biocompatible hydrogel of this invention has high electrical conductivity.

[0073] 3. Mechanical property test

[0074] The water-resistant and biocompatible hydrogel prepared in Example 3 was tested and found to have a tensile strength of 20 MPa, an elongation at break of 500%, and the ability to bear a weight of 70 kg.

[0075] This experiment demonstrates that the water-resistant, biocompatible hydrogel of this invention possesses strong mechanical properties.

[0076] 4. Anti-swelling and water resistance tests

[0077] The water-resistant biocompatible hydrogel prepared in Example 3 was soaked in water for three months and then removed. It was observed that its volume hardly changed and its mechanical properties did not decrease.

[0078] This experiment demonstrates that the water-resistant and biocompatible hydrogel of this invention can be used for a long time in complex and harsh environments, greatly expanding its application range.

[0079] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a water-resistant, biocompatible hydrogel, characterized in that, Specifically, the following steps are included: (1) Weigh each raw material according to the following weight proportions: 5-25 parts of hydroxypropyl cellulose, 2.5-15 parts of polyacrylamide and 25-75 parts of trihydroxyethyl methyl pyruvate; (2) Add hydroxypropyl cellulose and polyacrylamide to deionized water and stir to obtain a hydroxypropyl cellulose / polyacrylamide solution; The stirring temperature is 15-40℃, and the stirring time is 0.5-1h; in the hydroxypropyl cellulose / polyacrylamide solution, the mass concentration of hydroxypropyl cellulose is 1%-5%, and the mass concentration of polyacrylamide is 0.5%-3%. (3) The hydroxypropyl cellulose / polyacrylamide solution was allowed to stand to remove bubbles and then frozen to obtain frozen hydroxypropyl cellulose / polyacrylamide product; The settling and degassing time is 0.5-1 hour; the freezing temperature is -20°C, and the time is 2-6 hours. (4) Add trihydroxyethyl methyl pyruvate ammonium to deionized water and stir until homogeneous to obtain trihydroxyethyl methyl pyruvate ammonium solution; The mass concentration of the trihydroxyethyl methyl pyruvate ammonium solution is 5%-15%; (5) Add the hydroxypropyl cellulose / polyacrylamide frozen product to the trihydroxyethyl methyl pyruvate ammonium solution, let it stand to react, and rinse to obtain the water-resistant and biocompatible hydrogel. The settling time is 0.5-1 hour.

2. The method for preparing a water-resistant, biocompatible hydrogel according to claim 1, characterized in that, Weigh the raw materials according to the following proportions: 25 parts hydroxypropyl cellulose, 5 parts polyacrylamide, and 50 parts trihydroxyethyl methyl pyruvate.

3. The method for preparing a water-resistant, biocompatible hydrogel according to claim 1, characterized in that, Weigh the raw materials according to the following proportions: 25 parts hydroxypropyl cellulose, 15 parts polyacrylamide, and 50 parts trihydroxyethyl methyl pyruvate ammonium.

4. The method for preparing a water-resistant, biocompatible hydrogel according to claim 1, characterized in that, Weigh the raw materials according to the following proportions: 25 parts hydroxypropyl cellulose, 15 parts polyacrylamide, and 75 parts trihydroxyethyl methyl pyruvate.

5. The application of a water-resistant, biocompatible hydrogel prepared by any one of claims 1-4 in the preparation of wearable flexible sensors, conductive materials, or smart screen touchscreen materials.

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