CN112107721A

CN112107721A - Synthetic dressing with biological effect and preparation method thereof

Info

Publication number: CN112107721A
Application number: CN202011139139.6A
Authority: CN
Inventors: 黃俞智
Original assignee: Isoman Zhongshan Medical Equipment Co ltd
Current assignee: Isoman Zhongshan Medical Equipment Co ltd
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2020-12-22

Abstract

The invention relates to a synthetic dressing with biological effect and a preparation method thereof. The dressing contains cellulose, a plasticizer, a film-forming agent and hyaluronic acid treated by gamma rays. Compared with animal-derived collagen dressings extracted from tendons, ligaments, pericardium and the like, the synthetic dressing has excellent effects of good biocompatibility, promotion of fibrous tissue regeneration, anti-inflammation, short hydration time, good mechanical properties and the like.

Description

Synthetic dressing with biological effect and preparation method thereof

Technical Field

The invention belongs to the technical field of polymer medical biomaterials, and particularly relates to a synthetic dressing with a biological effect and a preparation method thereof.

Background

Skin tissues can be wounded by operations, accidents and the like, and if the wound surface cannot be covered in time, the problems of loss of tissue fluid, infection, pain, difficult wound healing and the like can be caused, and scars and even disabilities can be formed in severe cases. With the ongoing research on wound healing, it is increasingly recognized that dressings covering a wound surface are not only for physical protection, but also must promote wound healing.

With the development of materials science, the number of biological materials that can be used as dressings is increasing, and they can be divided into natural materials and synthetic materials, wherein the natural materials are usually animal-derived tissues, purified and extracted collagen, however, the genetic and genetic characteristics of livestock animals are closer to those of human beings, and if the animal from which the collagen is extracted comes from an infectious disease epidemic area, the risk of infection associated with the user may increase. Therefore, in recent years, scholars have shifted their goals to the development of synthetic biological dressings.

Although synthetic dressings do not have the risks associated with an active source, they are used as dressings for passive physical barriers and do not possess the biological effects of actively promoting tissue repair. Many scholars propose that drugs, growth factors and dressings are combined by structural attachment and chemical crosslinking methods, so that the dressings have the functions of resisting inflammation and promoting wound healing. For example, patent document CN1083392A discloses the use of a dressing as a matrix for drug delivery and embedding the drug in the structure. In patent document CN105797193A, the drug is grafted on the skeleton of the dressing through a chemical reaction. However, whatever method is used to carry the drug into the dressing, the difficulty and time of the process is significantly increased.

Hyaluronic acid is an important core component of extracellular matrix, is an important regulator of a plurality of physiological metabolic processes, and has excellent biocompatibility and biodegradability. The molecular weight and concentration of hyaluronic acid directly influence its biological effect, and the polymer hyaluronic acid is responsible for hydration, moisture retention and lubrication of tissue surfaces. In contrast, small molecule hyaluronic acid plays a role in promoting wound mitosis, immune stimulation and promoting angiogenesis.

However, small-molecule hyaluronic acid is expensive and not easy to prepare, so even though small-molecule hyaluronic acid has a biological effect of promoting wound healing, researchers and manufacturers still use a drug-loaded manner to make dressings have an effect of actively promoting wound healing.

Disclosure of Invention

In view of the above, the present invention is directed to an artificial total synthetic dressing having a biological effect and a method for preparing the same, which has excellent biocompatibility, can promote fibrous tissue regeneration, is anti-inflammatory, and has a short hydration time and good mechanical properties.

In order to solve the above technical problems, the present invention adopts the following technical means.

(1) A synthetic dressing having a biological effect, wherein said dressing comprises cellulose, a plasticizer, a film-forming agent, and hyaluronic acid treated with gamma radiation.

(2) The synthetic dressing according to (1), wherein the hyaluronic acid is a hyaluronic acid treated with gamma rays having an accumulated energy of 20-40 kgy.

(3) The synthetic dressing according to (1) above, wherein the hyaluronic acid is hyaluronic acid treated with gamma rays having an accumulated energy of 20 kgy.

(4) The synthetic dressing according to (1), wherein the molecular weight of the hyaluronic acid after the treatment with gamma rays is 2,000 to 300,000 daltons.

(5) The synthetic dressing according to (1), wherein the molecular weight of the hyaluronic acid after the treatment with gamma rays is 150,000 to 250,000 daltons.

(6) The synthetic dressing according to any one of the above (1) to (5), wherein the dressing is used as a wound dressing for general surgery, a hemostatic cotton, a guided bone regeneration membrane for dentistry, an anti-tissue adhesion barrier membrane for obstetrics and gynecology, or an artificial meninges and an anti-tissue adhesion barrier membrane for neurosurgery.

(7) A method of making a synthetic dressing having a biological effect, comprising the steps of:

performing gamma ray treatment on hyaluronic acid;

mixing hyaluronic acid treated by gamma rays with cellulose, a plasticizer and a film-forming agent; and

the mixture was freeze-dried to produce a synthetic dressing.

(8) The production method according to (7), wherein, in the gamma ray treatment, a gamma ray having an accumulated energy of 20 to 40 kgy is irradiated.

The synthetic dressing disclosed by the invention is prepared by using hyaluronic acid treated by gamma rays, so that the essential biological effect and biocompatibility of small-molecule hyaluronic acid are utilized, and the dressing actively promotes tissue repair of wounds under the condition of not using medicines, thereby further improving the welfare of patients. Compared with collagen dressing extracted from animal source, the synthetic dressing of the invention has good biocompatibility, can avoid potential pathogenic risk of animal-derived materials, and can realize the effects of promoting fibrous tissue regeneration and resisting inflammation without the assistance of drugs.

Drawings

FIG. 1 is a graph showing the fibroblast activity of L929 in the adjuvants of preparation examples 1 to 3.

FIG. 2 is a graph showing the anti-inflammatory activity of the adjuvants of preparation examples 1 to 3.

Detailed Description

Although there are many methods for depolymerizing hyaluronic acid, such as ultrasonic treatment, microwave treatment, oxidative degradation treatment, high-temperature high-pressure treatment, and acid hydrolysis treatment, these treatment methods all have the disadvantages of resource consumption cost, time consumption, and chemical residue.

The hyaluronic acid treated with gamma rays in the present invention can be obtained as follows: the hyaluronic acid with high molecular weight is properly packaged and put into gamma ray treatment equipment for irradiation, and the conditions of the gamma ray treatment are as follows: the irradiation accumulated energy is 20-40 kilogray, and preferably 20 kilogray.

After the specific gamma ray treatment, the molecular weight of the hyaluronic acid is 2,000-300,000 daltons, preferably 150,000-250,000 daltons.

Besides hyaluronic acid, the synthetic artificial dressing also contains cellulose, wherein the cellulose is used for providing a skeleton structure of the film agent and maintaining a fixed form of the film agent, and the cellulose contained in the dressing can be one or a mixture of more of carboxymethyl cellulose, carboxypropyl cellulose, ethyl cellulose and the like.

In addition, the synthetic artificial dressing also contains a plasticizer, the plasticizer is used for improving the ductility of the film agent, and the plasticizer used in the synthetic artificial dressing is a mixture of more than one of tributyl citrate, polyethylene glycol, glycerol, 1, 4-butanediol and the like.

The fully synthetic artificial dressing also contains a film-forming agent, the film-forming agent has the function of improving the structural strength of a finished product, and the film-forming agent used by the fully synthetic artificial dressing is one or a mixture of polyvinyl alcohol, polyvinylpyrrolidone, polyurethane, acrylic resin and the like.

The synthetic dressing with biological effect can be used for wound dressings in general surgery, hemostatic cotton, guiding bone regeneration membranes in dentistry, anti-tissue adhesion isolating membranes in obstetrics and gynecology department, artificial meninges in neurosurgery and anti-tissue adhesion isolating membranes.

In order to exhibit the effects of the present invention, the following is a detailed description of specific examples, and brief summary of formulation examples is shown in the following table.

TABLE 1

Preparation example 1

Mixing 10mL of 1.5% carboxymethyl cellulose solution, 10mL of 0.75% hyaluronic acid solution which is not treated by gamma rays and 10mL of 1.5% sodium alginate solution, then respectively adding 0.375% polyethylene glycol and polyvinyl alcohol solution, fully mixing, and moving the mixed solution into a 56 ℃ dry bath for standing for 2 hours for defoaming. After defoaming, 20mL of the mixed solution is poured into a bottom area of 30cm²The square mold is moved to a 56 ℃ oven for dehydration for 2 hours, then the mold is put into a-80 ℃ refrigerator for pre-freezing for 1 hour, after pre-freezing, the mold is moved to a freeze drier for freeze-drying under the pressure of less than 200 millitorr and at the temperature of-45 ℃. And taking out the sample after freeze-drying, adding a 2% calcium chloride cross-linked ethanol solution into the sample to react for 12Hr, placing the sample in 95% EtOH for cleaning after the reaction, and then carrying out secondary freeze-drying on the sample to finish the preparation.

Preparation example 2

10mL of a 1.5% carboxymethylcellulose solution, 10mL of a 0.75% hyaluronic acid (weight-average molecular weight: 141864 daltons) solution treated with gamma rays (cumulative energy: 40 kgy), and 10mL of a 1.5% sodium alginate solution were mixed, then 0.375% polyethylene glycol and a polyvinyl alcohol solution were added, respectively, and after thorough mixing, the mixed solution was transferred to a 56 ℃ dry bath and allowed to stand for 2hr for deaeration. After defoaming, 20mL of the mixed solution is poured into a bottom area of 30cm²The square mold is moved to a 56 ℃ oven for dehydration for 2 hours, then the mold is put into a-80 ℃ refrigerator for pre-freezing for 1 hour, after pre-freezing, the mold is moved to a freeze drier for freeze-drying under the pressure of less than 200 millitorr and at the temperature of-45 ℃. And taking out the sample after freeze-drying, adding a 2% calcium chloride cross-linked ethanol solution into the sample to react for 12Hr, placing the sample in 95% EtOH for cleaning after the reaction, and then carrying out secondary freeze-drying on the sample to finish the preparation.

Preparation example 3

Mixing 10mL of 1.5% carboxymethyl cellulose solution, 10mL of 0.75% hyaluronic acid (weight average molecular weight: 232443 Dalton) solution treated by gamma ray (accumulated energy of 20 kilograys) and 10mL of 1.5% sodium alginate solution, adding 0.375% polyethylene glycol and polyvinyl alcohol solution respectively, mixing completely, transferring the mixed solution into a 56 ℃ dry bath, standing for 2hr, and defoaming. After defoaming, 20mL of the mixed solution is poured into a bottom area of 30cm²The square mold is moved to a 56 ℃ oven for dehydration for 2 hours, then the mold is put into a-80 ℃ refrigerator for pre-freezing for 1 hour, after pre-freezing, the mold is moved to a freeze drier for freeze-drying under the pressure of less than 200 millitorr and at the temperature of-45 ℃. And taking out the sample after freeze-drying, adding a 2% calcium chloride cross-linked ethanol solution into the sample to react for 12Hr, placing the sample in 95% EtOH for cleaning after the reaction, and then carrying out secondary freeze-drying on the sample to finish the preparation.

The following tests were carried out on the products finally obtained in the above preparation examples 1 to 3:

and (3) thickness testing: soaking the sample in phosphate buffer solution to reach imbibition balance, taking out the sample and measuring the thickness of the sample by using a vernier caliper.

Hydration time test: the test piece was cut into 10X 10 mm, and then immersed in a phosphate buffer solution, and the time required for complete darkening due to wetting was measured.

The results are shown in Table 2 below.

TABLE 2

As can be seen from table 2, the dressing of formulation 2 and formulation 3 had a smaller thickness, closer to the thickness of the native tissue of the human body, than the dressing of formulation 1 containing hyaluronic acid that was not treated with gamma rays. In addition, the hydration time of the prepared dressing is not influenced no matter the hyaluronic acid used is treated by gamma rays or not, and the operation time of the operation of a doctor is not influenced in clinical use.

Testing the maximum tensile stress: cutting the sample into 5 x 50 mm, soaking the sample in phosphate buffer solution, taking out, patting dry, fixing on a bench clamp jig of a testing machine, stretching at the speed of 30cm per minute and recording. The results are shown in Table 3 below.

TABLE 3

Compared with the dressing of the preparation example 1 containing hyaluronic acid which is not treated by gamma rays, the dressings of the preparation examples 2 and 3 are higher than the dressing of the preparation example 1 in terms of tensile stress, and in the preparation example 3 containing hyaluronic acid which is treated by gamma rays and has the accumulated energy of 20 kgy, the mechanical property of the dressing is higher and is about 2.45 times of that of the preparation example 1, so that the dressing not only enables doctors to better operate in clinical use, but also can bear higher pressure and does not break in application.

Next, in order to confirm that the dressing containing hyaluronic acid treated with gamma rays of the present invention has a biological effect of promoting proliferation of fibrocyte, the present inventors conducted a cell test of biocompatibility as shown below.

The cell line selected in this test was L929 fibroblasts, and the results are shown in FIG. 1, wherein the cells were cultured in a 24-well plate at a concentration of 10000 cells/well, and after 24 hours of cell attachment, the medium was replaced with the dressing medium prepared in preparation examples 1, 2, and 3, and MTT cell activity test was performed every 24 hours of fixed time after replacing the medium, and the test was continued for 48 hours.

Based on the results, the cell activities at the initial 0 hours were comparable in each group, but the cell activities of the dressings of formulation 2 and 3 were superior to those of formulation 1 (using hyaluronic acid without gamma ray treatment) after 24 hours and 48 hours. It was thus confirmed that the dressing containing hyaluronic acid treated with gamma rays had the effect of increasing the activity of fibroblasts. In addition, the cell activity of formulation 3 was more excellent than that of formulation 2, indicating that the hyaluronic acid treated with gamma rays (accumulated energy of 20 kgy) had a more excellent biological effect than that of hyaluronic acid accumulated energy of 40 kgy, and that the effect of promoting proliferation of fibroblasts was better, indicating that the ability of promoting healing of wound tissue was stronger when applied.

In addition, in order to confirm that the dressing containing hyaluronic acid treated with gamma rays of the present invention has a biological effect of regulating an inflammatory response, the present inventors conducted an anti-inflammatory cell test as shown below.

The mouse macrophage strain RAW264.7 was seeded into 96-well plates at a concentration of 40000 particles/well in this experiment. After 24 hours of cell attachment, the cell culture medium was replaced with a medium containing endotoxin at a concentration of 1. mu.g/mL to stimulate the cells to undergo an inflammatory reaction, which served as a negative control group. In addition to investigating the anti-inflammatory activity of formulation 1, 2 and 3, an anti-inflammatory response inhibitor was also used as a positive control. The results are shown in FIG. 2.

As can be seen from the results, the endotoxin-treated cell inflammation reaction was significant, and the dressing of the invention in formulation examples 2 and 3, which contained hyaluronic acid treated with gamma ray, had an anti-inflammatory effect observed, wherein the anti-inflammatory effect of formulation example 3 was particularly significant. While formulation 1, which contained hyaluronic acid without gamma ray treatment, had no biological effect against inflammation at all.

Therefore, the above results demonstrate that the dressing containing hyaluronic acid treated by gamma ray of the present invention has anti-inflammatory biological effect, and the anti-inflammatory biological effect of the dressing containing hyaluronic acid with accumulated energy of 20 kgy of gamma ray treatment is more significant.

In addition, in the course of the study, in addition to the above formulation examples, the inventors of the present invention performed gamma ray treatment of hyaluronic acid with an accumulated energy of 60 kgy, and as a result, found that the weight average molecular weight of hyaluronic acid after the treatment was 59565 daltons, which was significantly lower than that of hyaluronic acid treated with gamma ray with an accumulated energy of 40 kgy. On the other hand, it was found from the above test results that the dressing of formulation example 2 (which was treated with gamma rays having an accumulated energy of 40 kgy and had a weight average molecular weight of hyaluronic acid of 141864 dalton) was inferior in biological effect to the dressing of formulation example 3 (which was treated with gamma rays having an accumulated energy of 20 kgy and had a weight average molecular weight of hyaluronic acid of 232443 dalton), and therefore, the present inventors determined that the dressing prepared with hyaluronic acid treated with gamma rays having an accumulated energy of 60 kgy could not obtain a good biological effect.

From the above results, it is understood that the synthetic dressing of the present invention has excellent effects of excellent biocompatibility, promotion of fibrous tissue regeneration, anti-inflammatory, short hydration time, good mechanical properties, and the like.

Claims

1. A synthetic dressing having a biological effect, characterized in that,

the dressing contains cellulose, a plasticizer, a film-forming agent and hyaluronic acid treated by gamma rays.

2. The synthetic dressing of claim 1,

the hyaluronic acid is treated by gamma rays with the accumulated energy of 20-40 kilogray.

3. The synthetic dressing of claim 1,

the hyaluronic acid is treated by gamma rays with the accumulated energy of 20 kilogray.

4. The synthetic dressing of claim 1,

the molecular weight of the hyaluronic acid treated by the gamma ray is 2,000-300,000 daltons.

5. The synthetic dressing of claim 1,

the molecular weight of the hyaluronic acid treated by the gamma ray is 150,000-250,000 daltons.

6. The synthetic dressing of any of claims 1-5, wherein said dressing is used as a general surgical wound dressing, a hemostatic cotton, a dental guided bone regeneration membrane, a gynecological anti-tissue adhesion barrier membrane, or a neurosurgical artificial meninges and anti-tissue adhesion barrier membrane.

7. A method of making a synthetic dressing having a biological effect, comprising the steps of:

performing gamma ray treatment on hyaluronic acid;

the mixture was freeze-dried to produce a synthetic dressing.

8. The production method according to claim 7,

in the gamma ray treatment, gamma rays with the accumulated energy of 20-40 kilogray are irradiated.