CN112618801A

CN112618801A - Method for preparing functional postoperative anti-adhesion material through 3D printing

Info

Publication number: CN112618801A
Application number: CN202011541972.3A
Authority: CN
Inventors: 程凤; 栗洪彬; 贺金梅; 黄玉东
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-04-09
Anticipated expiration: 2040-12-23
Also published as: CN112618801B

Abstract

A method for preparing a functional postoperative anti-adhesion material through 3D printing relates to a method for preparing an anti-adhesion material. Aims to solve the problems that the prior postoperative anti-adhesion material is easy to generate bonding failure and is limited in application to complex wound surfaces. The method comprises the following steps: preparing N, O-carboxymethyl chitosan, preparing aldehyde oxidized cellulose nano-fiber, preparing dopamine modified oxidized cellulose nano-fiber, respectively dissolving the N, O-carboxymethyl chitosan, epsilon-polylysine and the dopamine modified oxidized cellulose nano-fiber in deionized water, mixing to obtain printing ink, and performing 3D printing. The hydrogel disclosed by the invention has the characteristics of strong wet adhesion, self-repairability, high strength, high toughness, softness, easiness in skin fitting and the like, has the functions of resisting bacteria, stopping bleeding, controlling degradation, absorbing tissue exudate, keeping the wound surface moist and effectively promoting healing, and can accurately control the usage amount to meet the personalized requirements of patients through 3D printing. The invention is suitable for preparing the postoperative anti-adhesion material.

Description

Method for preparing functional postoperative anti-adhesion material through 3D printing

Technical Field

The invention relates to a method for preparing an anti-adhesion material.

Background

Postoperative adhesions are the most common adverse reactions after surgery, and millions of people all over the world are affected by postoperative abdominal adhesions, with medical costs reaching to billions of dollars. The formation of postoperative adhesions can lead to a plurality of serious consequences, such as chronic pain, female infertility, intestinal obstruction and the like, which not only increase the pain and economic burden of patients, but also seriously affect the daily life of the patients. Particularly in the field of obstetrics and gynecology, all women who undergo relatively simple operations such as ovarian cyst removal, hysteromyoma removal, salpingoplasty and the like are likely to suffer from postoperative adhesions. Therefore, prevention of post-operative adhesions is an important issue that all physicians need to solve urgently.

Current adhesion prevention materials include solid polymer or hydrogel films made of polysaccharides or synthetic polymers (absorbable and non-absorbable varieties) in order to act as a physical barrier between scar tissue and surrounding organs. The two most common commercial products are applied only to the abdomen, which are absorbable solid membranes composed of hyaluronic acid and carboxymethylcellulose, in the form of membranes (Seprafilm, Sanofi/Genzyme) or fabrics (interceded, Ethicon). These barriers often do not prevent or limit the occurrence of adhesions, can be dislodged by natural tissue movement, or can have an effect on the anti-adhesion of materials because films and fabrics do not cover the entire surface of irregular, folded and heavily organized structures (such as the large vessels and small intestine of the heart), and the materials tend to stick to instruments and gloves.

In recent years, injectable self-healing hydrogels formed by in situ crosslinking have received much attention as anti-adhesion barriers. The pre-gel solution of these hydrogels can be directly injected into injured tissues by injection, spray or laparoscopy, and the hydrogels can be formed in situ by spontaneous reaction under physiological conditions without any chemical reaction or stimulation by stimuli such as ultraviolet irradiation, temperature, etc. In addition, the hydrogel formed in situ is a soft and moist material, is adaptive to the extracellular matrix of natural tissues, and can fill up the defects of irregular shapes and accelerate wound healing. However, the hydrogel absorbs a large amount of body fluid and water to form a hydration layer, which seriously hinders the adhesion of the polymer to the wound surface and leads to obvious bonding failure. And the application amount of the hydrogel can not be accurately controlled according to the size, the shape and the position of the wound surface, so that the application of the hydrogel in the complicated wound surface is limited. At present, the most common antibacterial agents loaded in wound repair materials are organic antibacterial agents (antibiotics) and inorganic antibacterial agents (nano silver and the like), the use of antibiotics can cause the generation of drug resistance of the wound, and the use of chronic and complex wounds which are difficult to heal can cause the reduction of the wound repair effect; the negative effect of nano silver on human body, especially the long-time use or the increase of the use amount, is not clear in the clinical chronic toxic reaction mechanism.

As a natural antibacterial material, the epsilon-polylysine has biodegradability, no toxicity, edible property, low cost, difficult induction of drug resistance of bacteria, and broad-spectrum antimicrobial activity on gram-negative bacteria (such as escherichia coli), gram-positive bacteria (such as staphylococcus aureus) and fungi (such as candida albicans). The antibacterial material is applied to antibacterial materials, shows inherent antibacterial performance, does not need to add exogenous antibiotics, and has good application prospect in the field of wound repair.

Disclosure of Invention

The invention provides a method for preparing a functional postoperative anti-adhesion material by 3D printing, aiming at solving the problems that the existing postoperative anti-adhesion material is easy to generate bonding failure and is limited in application in complex wound surfaces.

The method for preparing the functional postoperative anti-adhesion material by 3D printing comprises the following steps:

firstly, preparing N, O-carboxymethyl chitosan:

adding chitosan powder into isopropanol, magnetically stirring for 8-24h at 25-80 ℃, then adding NaOH solution once every 5min, adding NaOH solution 5-12 times in total, dropwise adding chloroacetic acid into the mixed solution 5 times within 20min, adjusting the temperature of the reaction solution to 40-80 ℃ for reaction for 2-8h, stopping the reaction by using excess 75-80 v/v% ethanol water solution, washing the precipitate for 2-4 times by using 75-80 v/v% ethanol water solution, continuously washing the precipitate for 3-5 times by using absolute ethanol, and finally drying the precipitate in a vacuum drying oven to obtain water-soluble N, O-carboxymethyl chitosan (N, O-CS);

secondly, preparing aldehyde oxidized cellulose nano-fibers:

(1) dissolving tetramethylpiperidine oxynitride (TEMPO) and NaBr in deionized water until completely dissolving, dropwise adding the obtained reaction liquid into a 1 wt% cellulose nano-fiber aqueous solution, magnetically stirring for 20-30min, dropwise adding a 12 wt% NaClO solution, adjusting the pH of the reaction liquid to 10-12 by using a 0.2mol/L NaOH standard solution, reacting at room temperature for 1-3h, adding excessive absolute ethyl alcohol into the reaction liquid after the reaction is finished to terminate the chemical reaction, standing to remove a supernatant, centrifuging to obtain a precipitate, and centrifugally washing the obtained precipitate for 4-5 times by using absolute ethyl alcohol to obtain sodium cellulose oxide nano-fiber slurry (CNF);

(2) dispersing oxidized cellulose nanofiber slurry in deionized water to obtain oxidized cellulose nanofiber solution with the concentration of 1 wt%, and then dropwise adding NaIO into the oxidized cellulose nanofiber solution₄Reacting the solution at 40-60 deg.C in dark for 4-24 hr, adding ethylene glycol to stop reaction, stirring for 0.5-2 hr, purifying the reaction solution in dialysis bag for 3-6 days, and dialyzing to remove unreacted NaIO₄Then centrifuging to obtain aldehyde oxidized cellulose nanofiber (TOCNF);

thirdly, preparing the dopamine modified oxidized cellulose nano-fiber:

dispersing the aldehyde oxidized cellulose nanofiber in deionized water to obtain an aldehyde oxidized cellulose nanofiber solution with the concentration of 0.5-1 wt%, dropwise adding a dopamine solution with the concentration of 3.75-7.5 wt% into the aldehyde oxidized cellulose nanofiber solution, reacting for 0.5-3h, transferring the reaction solution into a dialysis bag after the reaction is finished, dialyzing for 3-5 days in a dark place, and centrifuging to obtain dopamine modified oxidized cellulose nanofiber (TOCNF-DA);

fourthly, 3D printing of the material:

respectively dissolving N, O-carboxymethyl chitosan, epsilon-polylysine (epsilon-PL) and dopamine modified oxidized cellulose nanofibers in deionized water, then mixing in equal volume to obtain uniform and stable printing ink, transferring the prepared printing ink into an injector, putting the injector into a feeding cylinder of a 3D printer, and printing according to a designed structure to obtain the printing ink.

The principle and the beneficial effects of the invention are as follows:

dopamine contains catechol and amine (lysine) groups, similar to 3, 4-dihydroxybenzene-l-alanine (DOPA) found in mussel adhesive protein; the catechol of dopamine can form strong covalent and non-covalent interaction with various inorganic and organic substrates, particularly when amino groups or thiol groups exist on the surface, the catechol can be oxidized into O-quinone, amino groups in N, O-carboxymethyl chitosan and epsilon-polylysine are crosslinked with the O-quinone through Michael addition or Schiff base, so that the hydrogel shows strong wet adhesion and flexibility; amino groups in N, O-CS and epsilon-PL and aldehyde groups in TOCNF-DA can be crosslinked to form dynamic Schiff base, so that the gel has good self-repairability; the TOCNF belongs to a cellulose derivative and has good mechanical properties unique to cellulose itself. The polyphenol substances can react with active residues of proteins and polysaccharides in blood to cause rapid coagulation of the blood, and a large amount of negative charges in the polyphenol structure can activate blood coagulation factors XII in an organism to further initiate the blood coagulation cascade reaction to improve the hemostatic capability of the organism, so that the polyphenol hemostatic agent is a novel hemostatic agent; the carboxyl on the TOCNF-DA can react with Fe in damaged red blood cells³⁺Has stronger complexing ability, leads to nonspecific aggregation of blood cells or blood platelets, promotes the generation of blood clots, and achieves the effect of hemostasis; n, O-CS is taken as a derivative of chitosan, and has the special performances of hemostasis, healing promotion and degradability of the chitosan; the epsilon-PL has biodegradability per se; the hydrogel can absorb a large amount of exudate or blood due to its natural porous structure and high water content,and the wound surface protective agent plays a role in shielding microorganisms, so that the wound surface part is kept in a quite humid environment, and the wound surface healing is promoted. The oxidized carboxymethyl TOCNF at the C6 position has good biodegradability and enzyme degradability.

In conclusion, the materials prepared by the invention integrate the advantages of various materials, the functional chitosan, epsilon-polylysine and dopamine modified oxidized cellulose nanofiber composite hydrogel prepared by the invention has the characteristics of strong wet adhesion, self-repairability, high strength, high toughness, softness, easy attachment with skin and the like, makes up the defects of the traditional hydrogel, improves the antibacterial property of the composite hydrogel better under the synergistic effect of the epsilon-polylysine and the chitosan, obtains the antibacterial hydrogel, the 3D printing postoperative anti-adhesion material integrating the functions of stopping bleeding, controlling degradation, absorbing tissue exudates, keeping the wound surface moist, effectively promoting healing and the like provides an ideal choice for the postoperative anti-adhesion material in the field, and can well meet the requirements of the ideal postoperative anti-adhesion material and the nursing and treatment requirements of medical workers.

The preparation method is easy to operate, the parameters are controllable, no cross-linking agent is required to be introduced, the materials are easy to obtain, the solvent is non-toxic or low-toxic, and the treatment and the use are safe; the 3D printing technology is adopted as a processing means, the usage amount can be accurately controlled according to the size, the shape and the position of a wound surface, the customized application is carried out, and the individual requirements of patients are effectively met.

CN108159508A discloses a preparation method of an anti-adhesion medical hydrogel material, and the difference between the application and CN108159508A is that:

(1) the raw materials are different:

the CN108159508A adopts carboxymethyl cellulose which is a completely carboxymethylated cellulose derivative, and is an alkalization reaction of cellulose and alkali to generate alkali cellulose and an etherification reaction of the alkali cellulose and monochloroacetic acid;

alkalization: [ C ]₆H₇O₂(OH)₃]_n+nNaOH→[C₆H₇O₂(OH)₂ONa]_n+nH₂O；

Etherification: [ C ]₆H₇O₂(OH)₂ONa]_n+nClCH₂COONa→[C₆H₇O₂(OH)₂OCH₂COONa]_n+nNaCl；

The cellulose nanofiber adopted by the invention is nano-sized and has high specific surface area, and sodium carboxylate groups are selectively introduced into a glucose unit C6 through TEMPO oxidation, so that the preparation method is different, and the obtained materials are different. When the carboxymethyl cellulose is used as an anti-adhesion dressing, the biological retention time at the wound surface part is short, and the postoperative anti-adhesion effect is poor. The cellulose nanofiber adopted by the preparation method has high flexibility and high strength, and has good cohesive force in hydrogel, so that the retention time of the hydrogel in a body can be prolonged, and the structure of the hydrogel can be kept.

(2) Carboxymethyl chitosan and N, O-carboxymethyl chitosan belong to the same derivatives of chitosan, but the preparation methods of the carboxymethyl chitosan and the N, O-carboxymethyl chitosan are different, the carboxymethyl chitosan and the N, O-carboxymethyl chitosan are both obtained by modifying chitosan under alkaline conditions, because the substitution activity of carboxymethyl on hydroxyl is higher than that of amino, when the substitution degree is less than 1, the substitution of carboxymethyl is mainly on hydroxyl rather than on amino, only when the substitution degree is close to 1 and higher than 1, the carboxymethyl substitution can be simultaneously carried out on amino to form N, O-carboxymethyl chitosan, and the chitosan derivative obtained by substitution on hydroxyl is carboxymethyl chitosan. The N, O-carboxymethyl chitosan can well inhibit the adhesion of fibroblasts, is used for preventing postoperative adhesion, and is more widely applied to the field of postoperative adhesion prevention than carboxymethyl chitosan.

(3) The invention introduces epsilon-polylysine as a natural antibacterial agent, and the epsilon-polylysine and N, O-carboxymethyl chitosan can play a role in synergistic antibacterial effect when being introduced into hydrogel, so that the hydrogel has more lasting antibacterial activity.

(4) The invention can realize the precision, controllability and designability of the intelligent flexible hydrogel material by adopting a 3D printing technology. The 3D printing technology can be customized according to the size and the position of a wound surface, and meets the personalized requirements of patients, which is a characteristic that CN108159508A does not have.

(5) The application is different; although the adopted hydrogel is anti-adhesion medical hydrogel, the invention is directed at postoperative adhesion of abdominal cavity, and has wider application range, and CN108159508A is only used for coating the surface of a patch material to prevent the patch from being adhered to visceral organs.

Drawings

FIG. 1 is a reaction scheme of the method for preparing TOCNF-DA according to the present invention.

Detailed Description

The technical scheme of the invention is not limited to the specific embodiments listed below, and any reasonable combination of the specific embodiments is included.

The first embodiment is as follows: the method for preparing the functional postoperative anti-adhesion material through 3D printing in the embodiment comprises the following steps:

firstly, preparing N, O-carboxymethyl chitosan:

secondly, preparing aldehyde oxidized cellulose nano-fibers:

thirdly, preparing the dopamine modified oxidized cellulose nano-fiber:

fourthly, 3D printing of the material:

Dopamine contains catechol and amine (lysine) groups, similar to 3, 4-dihydroxybenzene-l-alanine (DOPA) found in mussel adhesive protein; the catechol of dopamine can form strong covalent and non-covalent interaction with various inorganic and organic substrates, especially when amino or thiol groups exist on the surface, the catechol can be oxidized into O-quinone, amino in N, O-carboxymethyl chitosan and epsilon-polylysine is crosslinked with O-quinone through Michael addition or Schiff base, so that the hydrogel shows strong moistureAdhesion and flexibility; amino groups in N, O-CS and epsilon-PL and aldehyde groups in TOCNF-DA can be crosslinked to form dynamic Schiff base, so that the gel has good self-repairability; the TOCNF belongs to a cellulose derivative and has good mechanical properties unique to cellulose itself. The polyphenol substances can react with active residues of proteins and polysaccharides in blood to cause rapid coagulation of the blood, and a large amount of negative charges in the polyphenol structure can activate blood coagulation factors XII in an organism to further initiate the blood coagulation cascade reaction to improve the hemostatic capability of the organism, so that the polyphenol hemostatic agent is a novel hemostatic agent; the carboxyl on the TOCNF-DA can react with Fe in damaged red blood cells³⁺Has stronger complexing ability, leads to nonspecific aggregation of blood cells or blood platelets, promotes the generation of blood clots, and achieves the effect of hemostasis; n, O-CS is taken as a derivative of chitosan, and has the special performances of hemostasis, healing promotion and degradability of the chitosan; the epsilon-PL has biodegradability per se; the hydrogel can absorb a large amount of exudate or blood due to the natural porous structure and high water content, and has a barrier effect on microorganisms, so that the wound surface part is kept in a quite humid environment, and the healing of the wound surface is promoted. The oxidized carboxymethyl TOCNF at the C6 position has good biodegradability and enzyme degradability.

In conclusion, the materials prepared by the embodiment integrate the advantages of various materials, the functional chitosan, epsilon-polylysine and dopamine modified oxidized cellulose nanofiber composite hydrogel prepared by the embodiment has the characteristics of strong wet adhesion, self-repairability, high strength, high toughness, softness, easiness in jointing with skin and the like, the defects of the traditional hydrogel are overcome, the antibacterial performance of the composite hydrogel is better improved due to the synergistic effect of the epsilon-polylysine and the chitosan, and the antibacterial hydrogel is obtained, the 3D printing postoperative anti-adhesion material integrating the functions of stopping bleeding, controlling degradation, absorbing tissue exudates, keeping the wound surface moist, effectively promoting healing and the like provides an ideal choice for the postoperative anti-adhesion material in the field, and can well meet the requirements of the ideal postoperative anti-adhesion material and the nursing and treatment requirements of medical workers.

The preparation method of the embodiment is easy to operate, the parameters are controllable, no cross-linking agent is required to be introduced, the materials are easy to obtain, the solvent is non-toxic or low-toxic, and the treatment and the use are safe; the 3D printing technology is adopted as a processing means, the usage amount can be accurately controlled according to the size, the shape and the position of a wound surface, the customized application is carried out, and the individual requirements of patients are effectively met.

The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: step one, the drying time is 18-24h, and the drying temperature is 40-60 ℃.

The third concrete implementation mode: the present embodiment differs from the first or second embodiment in that: step one, the ratio of the mass of the chitosan to the volume of the isopropanol is 1 g: (5-12) mL; the ratio of the mass of the chitosan to the volume of the total added NaOH solution was 1 g: 2.5 mL; the concentration of the NaOH solution is 10 mol/L; the mass ratio of the chitosan to the chloroacetic acid is 1: (2-6). The chitosan is milk white powder, the deacetylation degree is 80%, and the grade is medical grade.

The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: and step two (1), the mass ratio of the cellulose nanofibers in the cellulose nanofiber aqueous solution to the NaClO solution is 1: 6; the mass of the cellulose nano-fiber, the tetramethylpiperidine oxynitride and NaBr in the cellulose nano-fiber aqueous solution is (60-150): 1: 10.

the fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: step two (2) the NaIO₄NaIO in solution₄The mass ratio of the oxidized cellulose nano-fiber to the oxidized cellulose nano-fiber in the oxidized cellulose nano-fiber slurry is 1 (1-4); the volume ratio of the mass of the oxidized cellulose nanofibers to the ethylene glycol in the oxidized cellulose nanofiber slurry is 1 g: 5 mL.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: and step two (2) the molecular weight cut-off of the dialysis bag is 3500.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: and step three, the molecular weight cut-off of the dialysis bag is 3500.

The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: thirdly, the mass ratio of the dopamine in the dopamine solution to the aldehyde oxidized cellulose nano-fibers is 4: 3.

the specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: fourthly, the mass ratio of the N, O-carboxymethyl chitosan to the epsilon-polylysine (epsilon-PL) to the dopamine modified oxidized cellulose nano-fiber is 1: 1: (1-6).

The detailed implementation mode is ten: the difference between this embodiment mode and one of the first to third embodiment modes is: step four, the 3D printing process comprises the following steps: the printing temperature is room temperature, the printing pressure is 25-50PSI, the printing speed is 5-10mm/s, and the needle specification is 18-23G. The epsilon-polylysine is white powder and is of pharmaceutical grade.

Example 1:

the 3D printing functional postoperative anti-adhesion material and the preparation method thereof are as follows:

(1) preparation of N, O-carboxymethyl chitosan: dispersing 5g of chitosan powder in 60mL of isopropanol, magnetically stirring for 12h at the temperature of 30 ℃, then adding NaOH solution into the mixed solution once every 5min, adding NaOH solution for 5 times totally, then dropwise adding 15g of chloroacetic acid into the mixed solution, adding 15g of chloroacetic acid into the mixed solution for 5 times within 20min, then adjusting the temperature of the reaction solution to 60 ℃ and reacting for 6 h; adding 80 v/v% ethanol aqueous solution into the reaction solution to terminate the reaction, then continuously washing the precipitate for 3 times by using the 80 v/v% ethanol aqueous solution, continuously washing the precipitate for 3 times by using absolute ethanol, and finally placing the purified precipitate in a vacuum drying oven for drying for 24 hours at the temperature of 40 ℃ to obtain water-soluble N, O-carboxymethyl chitosan (N, O-CS);

secondly, preparing aldehyde oxidized cellulose nano-fibers:

(1) dissolving 0.016g of tetramethylpiperidine nitroxide (TEMPO) and 0.16g of NaBr in 2mL of deionized water, dropwise adding the solution into 100mL of 1 wt% cellulose nanofiber aqueous solution after complete dissolution, magnetically stirring for 30min, then dropwise adding 5mL of NaClO solution (12 wt%) into the mixed solution, adjusting the pH of the reaction solution to 10 by using NaOH (0.2mol/L) standard solution, and reacting for 3h at room temperature; after the reaction is finished, adding excessive absolute ethyl alcohol into the reaction solution to stop the chemical reaction, standing to remove supernatant, then centrifuging to obtain a precipitate, and repeatedly centrifuging and washing the precipitate for 4 times to obtain cellulose sodium oxide rice fiber slurry (CNF);

(2) dispersing the prepared CNF in 100mL of deionized water to obtain 1 wt% oxidized cellulose nanofiber solution, and then dropwise adding 1g NaIO into the oxidized cellulose nanofiber solution₄Reacting for 6h under the condition of keeping out of the sun at 40 ℃, finally adding 5mL of ethylene glycol to terminate the reaction, continuing stirring for 2h, transferring into a dialysis bag (molecular weight is 3500) for purification treatment for 3 days, and dialyzing to remove unreacted NaIO₄Then centrifuging to obtain aldehyde oxidized cellulose nanofiber (TOCNF);

thirdly, preparing the dopamine modified oxidized cellulose nano-fiber: dispersing TOCNF in 50mL of deionized water to obtain 1 wt% dispersion, dropwise adding 6.5mL of 5 wt% dopamine solution into the TOCNF solution, reacting for 1h in a dark place, pouring the reaction solution into a dialysis bag (with a molecular weight of 3500) for dialysis in the dark place for 3 days after the reaction is finished, and then centrifuging to obtain TOCNF-DA;

fourthly, 3D printing of the material:

respectively dissolving N, O-CS, epsilon-polylysine (epsilon-PL) and TOCNF-DA in deionized water until the concentration is 4 wt%, and then mixing in equal volume to obtain uniform and stable printing ink; adding the uniformly mixed printing ink into an injector, placing the injector into a feeding cylinder of a 3D printer, designing a printing structure according to experimental needs to achieve custom-made and personalized printing, and performing 3D printing at room temperature, wherein the printing pressure is 40PSI, the printing speed is 5mm/s, and the needle head is 18G, so that the functional postoperative anti-adhesion material is obtained, and the bacteriostatic rate of the hydrogel prepared in the embodiment on staphylococcus aureus and escherichia coli reaches over 90%;

example 2

The 3D printing functional postoperative adhesion preventing material and the preparation method thereof are different from those in example 1 only in that: 3D printing of materials:

mixing 1 wt% of N, O-CS aqueous solution, 1 wt% of epsilon-PL aqueous solution and 4 wt% of TOCNF-DA aqueous solution in equal volume to obtain uniform and stable printing ink; adding the uniformly mixed printing ink into an injector, putting the injector into a feeding cylinder of a 3D printer, designing a printing structure according to experimental needs, customizing the printing structure to achieve custom-made and personalized printing, performing 3D printing at room temperature, wherein the printing pressure is 25PSI, the printing speed is 10mm/s, the needle head is 23G, and finally obtaining the functional postoperative anti-adhesion material. The rest is the same as in example 1.

Example 3

The difference between the 3D printing functional postoperative adhesion preventing material and the preparation method thereof in the embodiment and the embodiment 1 is that: 3D printing of materials:

mixing 2 wt% of N, O-CS aqueous solution, 2 wt% of epsilon-PL aqueous solution and 4 wt% of TOCNF-DA aqueous solution in equal volume to obtain uniform and stable printing ink; adding the uniformly mixed printing ink into an injector, putting the injector into a feeding cylinder of a 3D printer, designing a printing structure according to experimental needs, customizing to achieve the purpose of custom-made and personalized, performing 3D printing at room temperature, wherein the printing pressure is 25PSI, the printing speed is 10mm/s, the needle head is 21G, and finally obtaining the functional postoperative anti-adhesion material. The rest is the same as in example 1.

Example 4

mixing 3 wt% of N, O-CS aqueous solution, 3 wt% of epsilon-PL aqueous solution and 4 wt% of TOCNF-DA aqueous solution in equal volume to obtain uniform and stable printing ink; adding the uniformly mixed printing ink into an injector, putting the injector into a feeding cylinder of a 3D printer, designing a printing structure according to experimental needs, customizing to achieve the purpose of custom-made and personalized, performing 3D printing at room temperature, wherein the printing pressure is 30PSI, the printing speed is 10mm/s, the needle head is 18G, and finally obtaining the functional postoperative anti-adhesion material. The rest is the same as in example 1.

Table 1 shows the adhesion values of the hydrogels prepared in examples 1 to 4;

TABLE 1

	N,O-CS	ε-PL	TOCNF-DA	Adhesion (KPa)
					Example 1	4wt％	4wt％	4wt％	58.79
Example 2	1wt％	1wt％	4wt％	10.23
					Example 3	2wt％	2wt％	4wt％	53.59
Example 4	3wt％	3wt％	4wt％	75.89

Claims

The 3D printing method for preparing the functional postoperative anti-adhesion material is characterized by comprising the following steps: the method comprises the following steps:

firstly, preparing N, O-carboxymethyl chitosan:

adding chitosan powder into isopropanol, magnetically stirring for 8-24h at the temperature of 25-80 ℃, then adding NaOH solution once every 5min into the mixed solution, adding NaOH solution 5-12 times in total, then dropwise adding chloroacetic acid into the mixed solution 5 times within 20min, adjusting the temperature of the reaction solution to 40-80 ℃ to perform reaction for 2-8h, stopping the reaction by using excess 75-80 v/v% ethanol water solution, then washing the precipitate for 2-4 times by using 75-80 v/v% ethanol water solution, then continuously washing the precipitate for 3-5 times by using absolute ethanol, and finally drying the precipitate in a vacuum drying oven to obtain water-soluble N, O-carboxymethyl chitosan;

secondly, preparing aldehyde oxidized cellulose nano-fibers:

(1) dissolving tetramethylpiperidine oxynitride and NaBr in deionized water until the solutions are completely dissolved, dropwise adding the obtained reaction solution into a 1 wt% cellulose nanofiber aqueous solution, magnetically stirring for 20-30min, dropwise adding a 12 wt% NaClO solution, adjusting the pH of the reaction solution to 10-12 by using a 0.2mol/L NaOH standard solution, reacting at room temperature for 1-3h, adding excessive absolute ethyl alcohol into the reaction solution after the reaction is finished to terminate the chemical reaction, standing to remove a supernatant, centrifuging to obtain a precipitate, and centrifugally washing the obtained precipitate for 4-5 times by using the absolute ethyl alcohol to obtain a sodium cellulose oxide rice fiber slurry;

(2) dispersing oxidized cellulose nanofiber slurry in deionized water to obtain oxidized cellulose nanofiber solution with the concentration of 1 wt%, and thenDropwise adding NaIO into oxidized cellulose nanofiber solution₄Reacting the solution at 40-60 deg.C in dark for 4-24 hr, adding ethylene glycol to stop reaction, stirring for 0.5-2 hr, purifying the reaction solution in dialysis bag for 3-6 days, and dialyzing to remove unreacted NaIO₄Then centrifuging to obtain aldehyde oxidized cellulose nanofibers;

thirdly, preparing the dopamine modified oxidized cellulose nano-fiber:

dispersing the aldehyde oxidized cellulose nanofiber in deionized water to obtain an aldehyde oxidized cellulose nanofiber solution with the concentration of 0.5-1 wt%, dropwise adding a dopamine solution with the concentration of 3.75-7.5 wt% into the aldehyde oxidized cellulose nanofiber solution, reacting for 0.5-3h, transferring the reaction solution into a dialysis bag after the reaction is finished, dialyzing for 3-5 days in a dark place, and centrifuging to obtain the dopamine modified oxidized cellulose nanofiber;

fourthly, 3D printing of the material:

respectively dissolving N, O-carboxymethyl chitosan, epsilon-polylysine and dopamine modified oxidized cellulose nanofibers in deionized water, then mixing in equal volume to obtain uniform and stable printing ink, transferring the prepared printing ink into an injector, putting the injector into a feeding cylinder of a 3D printer, and printing according to a designed structure to obtain the printing ink.
2. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: step one, the drying time is 18-24h, and the drying temperature is 40-60 ℃.
3. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: step one, the ratio of the mass of the chitosan to the volume of the isopropanol is 1 g: (5-12) mL; the ratio of the mass of the chitosan to the volume of the total added NaOH solution was 1 g: 2.5 mL; the concentration of the NaOH solution is 10 mol/L; the mass ratio of the chitosan to the chloroacetic acid is 1: (2-6).
4. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: and step two (1), the mass ratio of the cellulose nanofibers in the cellulose nanofiber aqueous solution to the NaClO solution is 1: 6; the mass of the cellulose nano-fiber, the tetramethylpiperidine oxynitride and NaBr in the cellulose nano-fiber aqueous solution is (60-150): 1: 10.
5. the method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: step two (2) the NaIO₄NaIO in solution₄The mass ratio of the oxidized cellulose nano-fiber to the oxidized cellulose nano-fiber in the oxidized cellulose nano-fiber slurry is 1 (1-4); the volume ratio of the mass of the oxidized cellulose nanofibers to the ethylene glycol in the oxidized cellulose nanofiber slurry is 1 g: 5 mL.
6. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: and step two (2) the molecular weight cut-off of the dialysis bag is 3500.
7. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: and step three, the molecular weight cut-off of the dialysis bag is 3500.
8. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: thirdly, the mass ratio of the dopamine in the dopamine solution to the aldehyde oxidized cellulose nano-fibers is 4: 3.
9. the method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: fourthly, the mass ratio of the N, O-carboxymethyl chitosan, the epsilon-polylysine and the dopamine modified oxidized cellulose nano-fiber is 1: 1: (1-6).
10. The method for preparing the functional postoperative adhesion-preventing material by 3D printing according to claim 1, wherein the method comprises the following steps: step four, the 3D printing process comprises the following steps: the printing temperature is room temperature, the printing pressure is 25-50PSI, the printing speed is 5-10mm/s, and the needle specification is 18-23G.