阅读说明：本技术 聚乳酸透析膜及其制备方法、透析器 (Polylactic acid dialysis membrane, preparation method thereof and dialyzer ) 是由 董凡 马兰坤 祁腾腾 黄臣勇 于 2020-06-28 设计创作，主要内容包括：本发明提供一种聚乳酸透析膜及其制备方法、透析器,聚乳酸透析膜包括聚乳酸膜、含儿茶酚的胺类化合物和羧基化氧化石墨烯,聚乳酸膜上粘附有胺类化合物,羧基化氧化石墨烯通过氢键与胺类化合物连接；在制备聚乳酸透析膜时,施加机械力作用于聚乳酸膜表面,羧基化氧化石墨烯在机械力的作用下与含儿茶酚的胺类化合物连接。含儿茶酚的胺类化合物对聚乳酸膜进改性,改性后聚乳酸膜表面带有氨基和羟基,不会破坏聚乳酸分子链骨架,保持透析膜的强度；改性后的聚乳酸膜表面的氨基或羟基与羧基化氧化石墨烯的羧基形成氢键作用,保留羧基化氧化石墨烯上更多的羧基,提升聚乳酸膜表面的亲水性,羧基化氧化石墨烯在聚乳酸膜上分布更均匀,血液相容性更好。(The invention provides a polylactic acid dialysis membrane and a preparation method thereof, and a dialyzer, wherein the polylactic acid dialysis membrane comprises a polylactic acid membrane, an amine compound containing catechol and carboxylated graphene oxide, the amine compound is adhered to the polylactic acid membrane, and the carboxylated graphene oxide is connected with the amine compound through a hydrogen bond; when the polylactic acid dialysis membrane is prepared, mechanical force is applied to act on the surface of the polylactic acid membrane, and the carboxylated graphene oxide is connected with the catechol-containing amine compound under the action of the mechanical force. The amine compound containing catechol modifies the polylactic acid film, and the surface of the modified polylactic acid film is provided with amino and hydroxyl, so that the molecular chain skeleton of the polylactic acid is not damaged, and the strength of the dialysis film is maintained; the modified amino or hydroxyl on the surface of the polylactic acid film and the carboxyl of the carboxylated graphene oxide form a hydrogen bond effect, more carboxyl on the carboxylated graphene oxide is reserved, the hydrophilicity on the surface of the polylactic acid film is improved, the carboxylated graphene oxide is more uniformly distributed on the polylactic acid film, and the blood compatibility is better.)

1. Polylactic acid dialysis membrane, characterized by comprising: the film comprises a polylactic acid film, a catechol-containing amine compound and carboxylated graphene oxide, wherein the catechol-containing amine compound is adhered to the polylactic acid film, and the carboxylated graphene oxide is connected with the catechol-containing amine compound through a hydrogen bond.

2. The polylactic acid dialysis membrane according to claim 1, wherein:

the catechol-containing amine compound is 3, 4-dihydroxyphenylalanine.

3. The polylactic acid dialysis membrane according to claim 1 or 2, wherein:

per mm²The surface of the polylactic acid film is added with 8.1-40.8 mug of the carboxylated graphene oxide;

the hemolysis rate of the polylactic acid dialysis membrane is less than 5%.

4. The polylactic acid dialysis membrane according to claim 3, wherein:

per mm²The surface of the polylactic acid film is added with 8.1-10.2 mug of the carboxylated graphene oxide;

the hemolysis rate of the polylactic acid dialysis membrane is less than 2%.

5. The preparation method of the polylactic acid dialysis membrane is characterized by comprising the following steps: the preparation method prepares the polylactic acid dialysis membrane as claimed in any one of claims 1 to 4;

the preparation method comprises attaching the carboxylated graphene oxide to the polylactic acid film surface-functionalized with the catechol-containing amine compound by applying a mechanical force.

6. The method for preparing a polylactic acid dialysis membrane according to claim 5, wherein:

the mechanical force is formed by a pressure difference between the upper surface and the lower surface of the polylactic acid film, and the pressure difference is 0.02MPa to 0.14 MPa.

7. The method for preparing a polylactic acid dialysis membrane according to claim 5, wherein:

the carboxylated graphene oxide is added in the form of a carboxylated graphene oxide aqueous solution, and the concentration of the carboxylated graphene oxide aqueous solution is 20-50 [ mu ] g/mL.

8. The method for preparing a polylactic acid dialysis membrane according to claim 5, wherein:

the modification steps are as follows: soaking the polylactic acid film in the catechol-containing amine compound solution, and then washing the soaked polylactic acid film with deionized water, wherein the concentration of the catechol-containing amine compound solution is 0.5 mg/mL-2.0 mg/mL.

9. The method for preparing a polylactic acid dialysis membrane according to any one of claims 5 to 8, wherein:

the preparation method specifically comprises the following steps:

s1, modification step: soaking the polylactic acid film in the amine compound solution containing catechol for 12-72 h and slowly stirring, and then washing the soaked polylactic acid film with deionized water;

s2, adding carboxylated graphene oxide on the upper surface of the modified polylactic acid film, applying the mechanical force to the upper surface of the modified polylactic acid film, and applying the mechanical force for 30-120 min.

10. A dialyzer, characterized in that: the dialyzer comprises a housing and the polylactic acid dialysis membrane of any one of claims 1 to 4 filled in the housing.

Technical Field

The invention relates to the field of medical equipment, in particular to a polylactic acid dialysis membrane, a preparation method thereof and a dialyzer.

Background

The most ideal treatment for end-stage renal disease (ESRD) patients is kidney transplantation, but the number of patients is large, the source of kidney is seriously insufficient, and the cost of kidney transplantation is high, so hemodialysis becomes the most important means for the life continuation of ESRD patients. With the increase of patients with end-stage nephropathy in the population aging society of China, the demand of China on hemodialyzers is about 5 hundred million by 2023 years, which means that hemodialysis membranes in the hemodialyzers are high-demand medical equipment. At present, the hemodialysis membrane material widely used clinically is polysulfone and polyether sulfone, the two materials are petroleum-based materials, the petroleum-based materials are applied to the hemodialysis membrane and are required to be modified in biocompatibility, otherwise, the hemodialysis membrane of the petroleum-based materials is likely to generate a coagulation phenomenon in the using process. In order to reduce the risk possibly generated by the use of the dialyzer, researchers propose that polylactic acid is used as a dialysis membrane material, is a bio-based material, has good biocompatibility and is similar to the surface property of a human blood vessel, but has poor blood compatibility, and the polylactic acid membrane needs to be modified so as to have good blood compatibility.

In order to solve the problem of poor blood compatibility of polylactic acid, grapevine, Artur m, pinto et al (Biocompatibility of poly (lactic acid)) use a blending modification method to dope graphene oxide into a polylactic acid membrane so as to improve the blood compatibility of the polylactic acid membrane, but the blending modification method enables the graphene oxide to be embedded in the polylactic acid membrane, so that the graphene oxide on the surface of the polylactic acid membrane is very little, active sites such as carboxyl, hydroxyl and the like on the graphene oxide cannot be completely exposed on the surface of the polylactic acid membrane, and the blood compatibility effect on the surface of the polylactic acid membrane is limited.

Malanhun et al (Malanhun. polylactic acid film surface functionalization and blood compatibility research [ D ]. doctor academic thesis of Tianjin university of industry) fix carboxylated graphene oxide on the surface of polydopamine modified polylactic acid film by a chemical method in a covalent bond manner, so that the blood compatibility of the polylactic acid film is improved, but the prepared modified polylactic acid film has the problem that the carboxylated graphene oxide is not uniformly distributed on the surface of the polylactic acid film. The distribution of the carboxylated graphene oxide is not uniform, so that the surface of the polylactic acid film cannot be completely covered by the carboxylated graphene oxide, and the blood compatibility is not ideal.

The more uniform and firmer the distribution of the carboxylated graphene oxide on the surface of the polylactic acid film, the more hydrophilic groups (carboxyl groups) carried by the carboxylated graphene oxide are on the surface of the polylactic acid film, so that the hydrophilicity of the surface of the polylactic acid film is better, and the easier the surface of the polylactic acid film forms a hydration layer, so that the longer the calcium restoring time of the modified polylactic acid film is, the lower the hemolysis rate is, and the better the blood compatibility is. Therefore, how to improve the distribution uniformity of the carboxylated graphene oxide on the surface of the polylactic acid film and firmly fix the carboxylated graphene oxide on the surface of the polylactic acid film is an urgent problem to be solved.

Disclosure of Invention

The first purpose of the invention is to provide a polylactic acid dialysis membrane with better blood compatibility.

The second purpose of the invention is to provide a preparation method of the polylactic acid dialysis membrane.

A third object of the invention is to provide a dialyzer.

In order to achieve the first object, the present invention provides a polylactic acid dialysis membrane comprising a polylactic acid membrane, an amine compound containing catechol, and carboxylated graphene oxide, wherein the amine compound is adhered to the polylactic acid membrane, and the carboxylated graphene oxide is connected to the amine compound through a hydrogen bond.

According to the scheme, the amine compound containing catechol is used for carrying out surface functional modification on the polylactic acid membrane, the amine compound containing catechol has amino and hydroxyl groups, so that the surface of the modified polylactic acid membrane has abundant amino and hydroxyl groups, and the modification mode can not damage the molecular chain skeleton of the polylactic acid, so that the mechanical property of the polylactic acid membrane can be maintained, the membrane strength of the dialysis membrane is improved, and the risk of rupture of the polylactic acid dialysis membrane in the using process is reduced; amino or hydroxyl group on modified polylactic acid membrane surface and carboxyl on the carboxylation oxidation graphite alkene form the hydrogen bond effect, can not form the covalent bond with carboxyl on the carboxylation oxidation graphite alkene, can keep more carboxyl on the carboxylation oxidation graphite alkene, thereby it is more obvious to promote the hydrophilicity on modified polylactic acid membrane surface, the increase of hydrophilicity is still less to the absorption of protein and platelet, when difficult arouse the hemolysis, do not have the introduction of heparin, reduce the risk of bleeding, and because the hydrogen bond effect makes the carboxylation oxidation graphite alkene distribute more evenly on polylactic acid membrane, firm, thereby make the recalcification time of modified membrane longer, the hemolysis rate is lower, blood compatibility is better.

In a further scheme, the amine compound containing catechol is 3, 4-dihydroxyphenylalanine.

Therefore, the functional layer formed by the 3, 4-dihydroxyphenylalanine adheres to the surface of the polylactic acid film, the 3, 4-dihydroxyphenylalanine functional layer provides abundant amino and hydroxyl groups, the molecular chain skeleton of the polylactic acid is not damaged, and the mechanical property of the polylactic acid film is maintained.

Further, it is preferable that the thickness per mm is set to be small²The surface of the polylactic acid film is added with 8.1 to 40.8 mug of carboxylated graphene oxide, preferably 8.1 to 10.2 mug.

Therefore, the addition amount of the carboxylated graphene oxide in the range is that the water contact angle, the recalcification time and the hemolysis rate of the finally obtained polylactic acid dialysis membrane are optimal, the water contact angle, the recalcification time and the hemolysis rate of the finally obtained polylactic acid dialysis membrane are not continuously optimized, and the optimal performance of the dialysis membrane can be effectively realized and the production cost can be effectively controlled by controlling the addition amount range of the carboxylated graphene oxide.

In a further embodiment, the hemolytic rate of the polylactic acid dialysis membrane is less than 5%, preferably less than 2%

It can be seen that the lower the hemolysis rate, the better the blood compatibility.

In order to achieve the second object, the polylactic acid dialysis membrane preparation method provided by the invention prepares the polylactic acid dialysis membrane; the preparation method comprises the step of attaching the carboxylated graphene oxide to the polylactic acid film subjected to surface functionalization modification by the amine compound of catechol by applying mechanical force.

According to the scheme, under the action of external force, the carboxylated graphene oxide can overcome the steric hindrance effect, more hydrogen bonds are formed between the carboxylated graphene oxide and hydroxyl on the surface of the surface functionalized polylactic acid film, and the carboxylated graphene oxide is connected with the amine compound containing catechol through the hydrogen bonds, so that the hydrogen bonds are embedded into the surface of the polylactic acid film, and the fixed carboxylated graphene oxide is more uniform and firmer.

The further proposal is that the mechanical force is formed by the pressure difference between the upper surface and the lower surface of the modified polylactic acid film, the pressure of the upper surface of the film is larger than that of the lower surface, and the pressure difference is 0.02 MPa-0.14 MPa; preferably, the pressure difference is 0.1MPa to 0.14 MPa; further preferably, the pressure difference is 0.1 MPa.

Therefore, when the pressure difference is smaller, the speed of the carboxylated graphene oxide fixed on the surface of the polylactic acid membrane is lower, and the carboxylated graphene oxide fixed on the surface of the polylactic acid membrane is relatively less in the same time, so that the blood compatibility of the dialysis membrane is poorer; when the pressure difference is larger, the speed of the carboxylated graphene oxide fixed on the surface of the polylactic acid film is fast enough, the carboxylated graphene oxide fixed on the surface of the polylactic acid film is enough to completely cover the surface of the polylactic acid film in the same time, and after the pressure difference is continuously increased, the speed of the carboxylated graphene oxide fixed on the surface of the polylactic acid film is only increased, so that the combination of the carboxylated graphene oxide on the surface of the polylactic acid film is firmer by the pressure difference in the range, the proper pressure difference is maintained, and the production difficulty and the production cost are reduced.

In a further scheme, the carboxylated graphene oxide is added in the form of a carboxylated graphene oxide aqueous solution, and the concentration of the carboxylated graphene oxide aqueous solution is 20-50 [ mu ] g/mL.

The further scheme is that the modification steps are as follows: soaking the polylactic acid film in an amine compound solution containing catechol, and then washing the soaked polylactic acid film by deionized water, wherein the concentration of the amine compound solution is 0.5 mg/mL-2.0 mg/mL.

More specifically, the preparation method specifically comprises the following steps:

s1, modification step: soaking the polylactic acid film in an amine compound solution containing catechol for 12-72 h, slowly stirring, and then washing the soaked polylactic acid film with deionized water;

s2, adding carboxylated graphene oxide on the upper surface of the modified polylactic acid film, and applying mechanical force to the upper surface of the modified polylactic acid film for 30-120 min.

In order to achieve the third object, the present invention provides a dialyzer comprising a housing and a polylactic acid dialysis membrane as described above filled in the housing.

According to the scheme, after the polylactic acid dialysis membrane is subjected to surface functionalization modification on the polylactic acid membrane through the amine compound, the carboxylated graphene oxide is connected with the amine compound through the hydrogen bond by the external mechanical force, so that the carboxylated graphene oxide is uniformly distributed on the surface of the polylactic acid membrane, the blood compatibility of the polylactic acid dialysis membrane is better, and the polylactic acid dialysis membrane is applied to a dialyzer to better purify blood.

Detailed Description

The polylactic acid dialysis membrane comprises a polylactic acid membrane, an amine compound containing catechol and carboxylated graphene oxide, wherein the amine compound containing the catechol is adhered to the polylactic acid membrane, and the carboxylated graphene oxide is connected with the amine compound containing the catechol through a hydrogen bond. The amine compound containing catechol is used for carrying out surface functional modification on the polylactic acid film, and an amine compound functional layer containing catechol is formed on the surface of the polylactic acid film, so that the surface of the polylactic acid film is provided with abundant amino and hydroxyl groups, the modification can not damage the molecular chain skeleton of the polylactic acid, the mechanical property of the polylactic acid film is maintained, the strength of the polylactic acid film is maintained, and the risk of rupture of the polylactic acid dialysis film in the using process is reduced. The amino group or hydroxyl group on the surface of the modified polylactic acid film forms a hydrogen bond effect with the carboxyl on the carboxylated graphene oxide, does not form a covalent bond with the carboxyl, and can retain more carboxyl on the carboxylated graphene oxide, so that the hydrophilicity of the surface of the modified polylactic acid film is improved more obviously, and the hydrogen bond effect enables the carboxyl on the carboxylated graphene oxide to form a hydrogen bond effectThe distribution of the carboxylated graphene oxide on the polylactic acid membrane is more uniform and firmer, so that the modified membrane has longer calcium covering time, lower hemolysis rate and better blood compatibility. Preferably, the catechol-containing amine compound is 3, 4-dihydroxyphenylalanine. Per mm²The polylactic acid film surface of (2) is added with 8.1 to 40.8 mug of carboxylated graphene oxide, preferably, each mm²10.2 mu g of carboxylated graphene oxide is added to the surface of the polylactic acid membrane, and the blood compatibility of the finally obtained polylactic acid dialysis membrane is optimal under the condition of the addition amount of the carboxylated graphene oxide. The hemolysis rate of the polylactic acid dialysis membrane is less than 5%, preferably the hemolysis rate of the polylactic acid dialysis membrane is less than 3%, further preferably the hemolysis rate of the polylactic acid dialysis membrane is less than 2%, and the lower the hemolysis rate, the better the blood compatibility.

The preparation method of the polylactic acid dialysis membrane comprises the following steps:

before modification of a polylactic acid film, preparing an amine compound solution of catechol and a carboxylated graphene oxide solution, wherein the preparation steps of the amine compound solution of the catechol are as follows: 0.1M bis (2-hydroxyethylamino) tris (hydroxymethyl) methane was mixed with 0.6M sodium chloride to prepare a buffer solution having a pH of 7, and the amine compound of catechol was dissolved in the buffer solution to prepare a solution of the amine compound of catechol at a concentration of 0.5mg/mL to 2.0 mg/mL.

The preparation method of the carboxylated graphene oxide comprises the following steps: adding concentrated nitric acid and concentrated sulfuric acid into graphene oxide powder, and stirring at 60 ℃ for 12h to obtain carboxylated graphene oxide; the mass-to-volume ratio of the graphene oxide to the concentrated nitric acid to the concentrated sulfuric acid is 1:20:60 (m: v: v).

The modification steps are as follows: soaking the polylactic acid film in the amine compound solution of catechol, and then washing the soaked polylactic acid film with deionized water for 2-8 h.

After modification, adding carboxylated graphene oxide on the upper surface of the modified polylactic acid film, and applying mechanical force to the upper surface of the modified polylactic acid film, wherein the mechanical force is formed by the pressure difference between the upper surface and the lower surface of the modified polylactic acid film, and the pressure difference is 0.02 MPa-1.4 MPa, preferably 0.1 MPa-0.14 MPa; further preferably, the pressure difference is 0.1MPa, the time for applying mechanical force is 30min to 120min, and then the carboxylated graphene oxide which is not firmly fixed is washed away by using deionized water for 0.5h to 2 h.

Under the effect of mechanical force, the steric hindrance effect can be overcome to carboxylation oxidation graphite alkene, and carboxylation oxidation graphite alkene forms more hydrogen bonds with the surperficial hydroxyl of surface functionalization polylactic acid membrane to the hydrogen bond is connected with the amine compound of catechol, thereby imbeds polylactic acid membrane surface, makes fixed carboxylation oxidation graphite alkene more even more firm, improves polylactic acid dialysis membrane's blood compatibility. The mechanical force is formed by the pressure difference between the upper surface and the lower surface of the modified polylactic acid film, and the mechanical force can be formed by performing air treatment on the upper surface of the polylactic acid film through external equipment to enable the pressure of the upper surface of the polylactic acid film to be larger than that of the lower surface of the polylactic acid film.

The dialyzer of the present invention comprises a polylactic acid dialysis membrane as described above. After the polylactic acid dialysis membrane is subjected to surface functionalization modification by the amine compound containing catechol, the carboxylated graphene oxide is connected with the amine compound containing catechol by a hydrogen bond through an external mechanical force, so that the carboxylated graphene oxide is uniformly distributed on the surface of the polylactic acid membrane, the blood compatibility of the polylactic acid dialysis membrane is better, and the polylactic acid dialysis membrane is applied to a dialyzer to better purify blood.

The invention will be better understood by reference to the following further description of specific comparative examples.

The effect of blood compatibility of the polylactic acid dialysis membrane is reflected by a water contact angle, a recalcification time (PRT) and a Hemolysis Rate (HR), wherein the smaller the water contact angle is, the better the surface hydrophilicity of the polylactic acid dialysis membrane is; the longer the recalcification time, the lower the hemolysis rate, indicating better hemocompatibility.

The invention detects the water contact angle, the recalcification time (PRT) and the Hemolysis Rate (HR) of the polylactic acid dialysis membrane, and the detection method comprises the following steps:

1. water contact Angle test

And (3) flattening the film sample, flatly paving the film sample on a loading platform, enabling the surface to be detected to be upward, leveling a base line, then dripping 5 mu L of deionized water on the surface of the film, adjusting a rotary tester, and reading a contact angle. Three replicates were measured for each film, 7 test points were taken for each sample, and the test results were averaged.

2. Recalcification Time (PRT) test

(1) 5mL of sheep whole blood is taken, centrifuged (2000g, about 4411r/min, 10min), and supernatant is taken to obtain Platelet Poor Plasma (PPP);

(2) cutting the hemodialysis membrane into 0.5 x 0.5cm²Placing the membrane into a 24-hole cell culture plate, labeling, dripping 0.1mL of the PPP onto the surface of each membrane in a constant-temperature water bath at 37 ℃, and keeping for one minute;

(3) 0.1mL of 0.025mol/L CaCl preheated to 37 deg.C₂And dripping the solution on the surface of the membrane, starting timing, continuously picking the solution by using a fine iron wire, stopping timing until the first fibrin thread appears, and recording the calcium-restoring time.

3. Hemolytic Rate (HR) test

(1) Cutting the hemodialysis membrane into small square pieces of 0.5cm by 0.5cm, washing the membrane for 10min by using deionized water, and then washing the membrane for 10min by using a NaCl solution with the mass fraction of 0.9%;

(2) soaking the membrane in 0.9% NaCl solution at 37 deg.C for 30 min;

(3) adding 200 mu L of sheep whole blood into a membrane-containing NaCl solution, a membrane-free NaCl solution and pure water respectively, and keeping the temperature constant at 37 ℃ for 1 h;

(4) the above samples were centrifuged (800g, about 2790r/min, 10min) and the supernatant taken and the absorbance measured at 545nm using an ultraviolet spectrophotometer. 0.9 wt% NaCl solution as negative control and deionized water as positive control, and the hemolysis rate is calculated by the following formula:

HR ═ AS (AS-AN)/(AP-AN) × 100% formula (1)

In the formula: AS-absorbance of the sample;

AN — absorbance of negative control;

AP-absorbance of positive control.

Comparative experiment group 1