Biological pollution-resistant coating, preparation method thereof and implantable medical device
阅读说明：本技术 一种抗生物污染的涂层及其制备方法、植入式医疗器械 (Biological pollution-resistant coating, preparation method thereof and implantable medical device ) 是由 许冠哲 叶乐 高猛 于 2019-10-15 设计创作，主要内容包括：本发明涉及一种抗生物污染的涂层及其制备方法、植入式医疗器械。一种抗生物污染的涂层,包括底层和表层,所述底层为聚多巴胺,所述表层为自组装的离子互补型多肽。其制备过程为：在预定的基材表面原位聚合形成聚多巴胺层；在所述聚多巴胺层的表面上涂覆或浸渍所述离子互补性多肽,之后经过诱导自组装,形成自组装的离子互补型多肽层。本发明能够解决现有涂层稳定性低、不可降解、附着力小等问题。(The invention relates to an anti-biological-pollution coating, a preparation method thereof and an implantable medical device. An anti-biofouling coating comprising a bottom layer and a top layer, the bottom layer being polydopamine and the top layer being a self-assembling ion-complementary polypeptide. The preparation process comprises the following steps: in-situ polymerizing on the surface of a preset base material to form a polydopamine layer; and coating or impregnating the ion-complementary polypeptide on the surface of the polydopamine layer, and then forming a self-assembled ion-complementary polypeptide layer through induced self-assembly. The invention can solve the problems of low stability, nondegradable property, small adhesive force and the like of the existing coating.)
1. An anti-biocontamination coating comprising a substrate and a surface layer, said substrate being polydopamine and said surface layer being a self-assembled ion-complementary polypeptide.
2. The anti-biocontamination coating of claim 1, wherein said amino acid sequence of said ion-complementary polypeptide is at least one of the following formulas:
[(X1X2X3)a(X1’X2’X3’)b]n，[(X1’X2’X3’)b(X1X2X3)a]n，
wherein, X1、X2And X3Selected from one of nonpolar uncharged amino acid, polar uncharged amino acid and basic amino acid, X1’、X2' and X3' one selected from the group consisting of a non-polar uncharged amino acid, a polar uncharged amino acid, and an acidic amino acid,
and X1、X2And X3Only one nonpolar uncharged amino acid, one polar uncharged amino acid and one basic amino acid,
and X1’、X2' and X3In' there is only one non-polar uncharged amino acid, one polar uncharged amino acid and one acidic amino acid;
a is a positive integer of 1-5, b is a positive integer of 1-5, and n is a positive integer of 1-5.
3. Method for the preparation of an anti-biocontamination coating according to claim 1 or 2, comprising the steps of:
in-situ polymerizing on the surface of a preset base material to form a polydopamine layer;
and coating or impregnating the ion-complementary polypeptide on the surface of the polydopamine layer, and then forming a self-assembled ion-complementary polypeptide layer through induced self-assembly.
4. The method of claim 3, wherein the in-situ polymerization is carried out by:
and soaking the base material in 1-8mg/mL dopamine solution for more than 24 hours, wherein the concentration of the dopamine solution is preferably 3-4 mg/mL.
5. The method of claim 3, wherein the method for inducing self-assembly is:
the ion-complementary polypeptide completes self-assembly triggered in a solution environment containing amino acids and ions.
6. The method according to claim 5, wherein the solution environment is a DMEM medium;
preferably, the reaction time in the solution environment containing amino acid and ion is more than 4 h.
7. The method according to claim 6, wherein the concentration of glucose in the DMEM medium is 3-5 g/L.
8. The method of claim 3, wherein the ion-complementing polypeptide is impregnated on the surface of the polydopamine layer by:
soaking in 1 mg/mL-8 mg/mL ion complementary polypeptide solution for over 24 h.
9. An implantable medical device, characterized in that the surface of the device is provided with an anti-biocontamination coating as claimed in claim 1 or 2.
Technical Field
The invention relates to the field of medical instruments, in particular to an anti-biological-pollution coating, a preparation method thereof and an implantable medical instrument.
Background
Biological contamination refers to the condition that biologically active substances such as proteins, cells and the like are adhered to the surface of a material, thereby affecting the performance of the material. Biological contamination often appears on the surface of an implanted medical device, and then causes the occurrence of thrombosis, inflammation and other conditions, which affect the treatment effect slightly and the life of a patient seriously. The surface of the implantable medical device is treated to reduce the biological pollution on the surface, and the treatment is a necessary flow in the manufacturing process of the related medical device.
In the research at home and abroad, after the surface of a base material is treated by materials such as polyethylene glycol (PEG) and derivatives thereof, zwitterionic polymers and the like, the biological pollution condition can be effectively reduced. The principle of the biological anti-fouling of polyethylene glycol and its derivatives is its steric repulsion effect, when proteins or cells approach the surface of long-chain PEG, PEG is compressed. While this compressed conformation is unstable, the PEG chains will then stretch and thus repel proteins or cells. The anti-fouling principle of the zwitterionic polymer is that a large number of positive and negative charge groups contained in a molecular chain of the zwitterionic polymer endow the zwitterionic polymer with super-hydrophilicity, the molecular chain with super-hydrophilicity can gather a large number of water molecules around the molecular chain to form a hydration layer, and the hydration layer can prevent proteins or cells from being adsorbed on the surface of a material.
The polyethylene glycol anti-fouling coating has the advantages of simple coating method, low cost and excellent biocompatibility, and is an anti-fouling material which is most widely applied at present. However, PEG has a series of problems in practical application: 1. PEG is easily affected by the aerobic environment in blood and falls off from the substrate; 2. PEG has poor long-term stability at body temperature. The stability of the existing zwitterionic polymer (such as carboxyl betaine type polymer, phosphorylcholine type polymer and the like) is higher than that of PEG, but the synthesis cost is high, the fixing or attaching difficulty between the zwitterionic polymer and a substrate is high, and most of the zwitterionic polymer is not degradable. Therefore, there is a need to develop a coating that can combine various properties.
Disclosure of Invention
The invention aims to provide a biological pollution-resistant coating which can solve the problems of low stability, nondegradable property, small adhesive force and the like of the existing coating.
In order to achieve the above purpose, the invention provides the following technical scheme:
an anti-biofouling coating comprising a bottom layer and a top layer, the bottom layer being polydopamine and the top layer being a self-assembling ion-complementary polypeptide.
The coating takes polydopamine as a bottom layer, can stably bond self-assembled ion complementary polypeptide on the surface to the surface of a base material, and the self-assembled ion complementary polypeptide on the surface layer has super-strong hydrophilicity and can prevent the adsorption of bioactive substances such as cells, proteins and the like. In addition, the invention selects the specific combination of polydopamine and ion complementary polypeptide, and can achieve the following technical effects.
1. When the coating is applied to various types of substrates (especially implantable medical devices), the coating is not easy to fall off:
on one hand, the polydopamine has strong adsorption capacity and can be stably adsorbed on the surface of a base material, on the other hand, the ion complementary type polypeptide is characterized in that adjacent structural units respectively contain acidic amino acid and basic amino acid, and the series of polypeptide also contains a polar uncharged amino acid and nonpolar uncharged amino acid alternate combined structure, and the characteristics enable the polydopamine to form an β folded self-assembled structure through electrostatic interaction force and hydrophilic-hydrophobic interaction force, so that the polydopamine can be better adsorbed on the surface of a polydopamine layer.
2. The self-assembled ion complementary polypeptide is stable in a body fluid environment, is not easy to deteriorate and has long service life:
peptide bonds in the self-assembled ion-complementary polypeptide are broken only in the presence of strong acid, strong base and digestive enzyme, and the self-assembled ion-complementary polypeptide has β -folded secondary conformation, so that structural damage caused by body temperature cannot occur, namely high stability in vivo is achieved.
3. The ion complementary polypeptide is degradable biocompatible material, and its self-assembling method is simple and does not need complex polymerization process.
Compared with the existing biological pollution-resistant coating, the invention has the advantages of high stability, safety, environmental protection, simple synthesis and the like.
The ion complementary polypeptide has the same structure with the polypeptide characteristics found in the study of L-DNA binding protein by Zhang eosin, namely, the ion complementary polypeptide can form a fibrous structure in water, has hydrogen bond and electrostatic interaction among sequences, has extremely strong hydrophilicity on the surface after self-assembly, and can form a hydration layer in body fluid or in a solution environment.
The self-assembly according to the invention may be spontaneous or induced.
On the basis of the above, further improvements can be made to improve other properties, as follows.
In order to increase the hydrophilicity of the coating surface layer, preferably, the amino acid sequence of the ion-complementary polypeptide is at least one of the following formulas:
[(X1X2X3)a(X1’X2’X3’)b]n，[(X1’X2’X3’)b(X1X2X3)a]n，
wherein, X1、X2And X3Selected from one of nonpolar uncharged amino acid, polar uncharged amino acid and basic amino acid, X1’、X2' and X3' one selected from the group consisting of a non-polar uncharged amino acid, a polar uncharged amino acid, and an acidic amino acid,
and X1、X2And X3At least two of the amino acids are not nonpolar uncharged amino acids, polar uncharged amino acids or basic amino acids at the same time,
and X1’、X2' and X3' at least two of which are not simultaneously nonpolar uncharged amino acids, polar uncharged amino acids or acidic amino acids;
a is a positive integer of 1-5, b is a positive integer of 1-5, and n is a positive integer of 1-5.
In the above, X1、X2And X3Wherein only one non-polar uncharged amino acid, one polar uncharged amino acid and one basic amino acid is defined as: x1、X2And X3Wherein two or three amino acids cannot be of the same type, which refers to those types of the invention defined above. X1’、X2' and X3The definition of' is similar thereto.
There are several types of polypeptide sequences that satisfy the above conditions:
[(XmX+Xp)a(Xm X-Xp)b]n(I)，
[(XmX-Xp)a(Xm X+Xp)b]n(II)，
[(XpX+Xm)a(XpX-Xm)b]n(III)，
[(XpX-Xm)a(XpX+Xm)b]n(IV)，
[(X+XmXp)a(X-XmXp)b]n(V)，
[(X+XpXm)a(X-XpXm)b]n(VI)，
[(X-XmXp)a(X+XmXp)b]n(VII)，
[(X-XpXm)a(X+XpXm)b]n(VIII)，
[(XmXpX+)a(XmXpX-)b]n(IX)，
[(XpXmX+)a(XpXmX-)b]n(X)，
[(XmXpX-)a(XmXpX+)b]n(XI)，
[(XpXmX-)a(XpXmX+)b]n(XII)。
wherein, XpRepresented by the nonpolar uncharged amino acid, XmRepresented by polar uncharged amino acids, X+Representative are basic amino acids, X-Represents an acidic amino acid, a represents a positive integer of 1 to 5, b represents a positive integer of 1 to 5, and n represents a positive integer of 1 to 5.
Preferably, the amino acid sequence of the ion-complementary polypeptide is:
GRVGEVGRVGEVGRVGEV、SKISDISKISDISKISDI、HGFEGFHGFEGFH-GFEGF，AYRSMDAYRSMDAYRSMD，HNPEQLHNPEQLHNPEQL，YKWTDI-YKWTDIYKWTDI。
in the above-listed polypeptide sequences, the abbreviation of amino acid is defined as the one commonly used in the art, for example, G is glycine, R is arginine, and V is valine.
The anti-biological-contamination coating can be prepared by the following method:
in-situ polymerizing on the surface of a preset base material to form a polydopamine layer;
and coating or impregnating the ion-complementary polypeptide on the surface of the polydopamine layer, and then forming a self-assembled ion-complementary polypeptide layer through induced self-assembly.
The predetermined substrate refers to the substrate to which the coating is applied, including but not limited to: medical implantable catheters, implantable sensors, implantable drainage devices, implantable drug delivery devices, implantable electrical stimulators, implantable functional fillers, and the like for long-term or short-term use.
In-situ polymerization is used in order to make dopamine adsorbed on the substrate more stable, since it is easily polymerized.
Wherein, the in-situ polymerization method is preferably as follows:
the base material is soaked in 1 mg/mL-8 mg/mL dopamine solution for more than 24h, the concentration of the dopamine solution can be any concentration between 1 mg/mL-8 mg/mL, for example, 1mg/mL, 2mg/mL, 3mg/mL, 4mg/mL, 5mg/mL, 6mg/mL, 7mg/mL, 8mg/mL and the like, and preferably 3-4 mg/mL.
The soaking method can be carried out at normal temperature and normal pressure, so that the production difficulty and the process cost are greatly reduced, and complex and expensive equipment is not required.
The method for inducing self-assembly is preferably as follows:
the ion-complementary polypeptide completes self-assembly triggered in a solution environment containing amino acids and ions.
The solution environment of the invention containing amino acids and ions is generally compatible with ion-complementary polypeptides, with different polypeptides being compatible with optimal induction conditions.
Preferably, the solution environment is DMEM medium, and preferably phenol red free.
Preferably, the concentration of glucose in the DMEM medium is 3-5 g/L, and the more preferable concentration is 4.5 g/L.
Preferably, the reaction time in the solution environment containing amino acid and ion is more than 4 h.
Preferably, the method for impregnating the ion-complementing polypeptide on the surface of the polydopamine layer is as follows:
soaking in 1 mg/mL-8 mg/mL ion complementary polypeptide solution for over 24 h.
The solvent used in the solution of the ion-complementary polypeptide of the present invention is any conventional solvent, such as water.
The solvent used by the dopamine solution is water or lower alcohol and the like.
After in situ polymerization to form the polydopamine layer, the substrate is preferably rinsed to remove residual solution or dopamine monomer molecules.
After the self-assembly is completed, the substrate is preferably heat dried.
As mentioned above, the coating of the invention has good biological pollution resistance, can be used in the fields of biological medicine, marine antifouling and the like, and has more outstanding performance particularly when being used for an implanted medical apparatus, namely the surface of the implanted medical apparatus is provided with the biological pollution resistance coating. Such implantable medical devices include, but are not limited to: medical implantable catheters, implantable sensors, implantable drainage devices, implantable drug delivery devices, implantable electrical stimulators, implantable functional fillers, and the like for long-term or short-term use.
In summary, compared with the prior art, the invention achieves the following technical effects:
(1) the stability is high;
(2) the hydrophilicity is strong, and the biological pollution resistance is better;
(3) the biocompatibility is good, the degradable is realized, and the implant is safer;
(4) the preparation process is simple, does not involve severe reaction conditions, does not need complex and expensive equipment, has low cost and is easier for industrial popularization.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings.
FIG. 1 is a scanning electron micrograph of the surface of GRVGEVGRVGEVGRVGEV polypeptide coating in example 1 of the present invention, from which it can be seen that GRVGEVGRVGEVGRVGEV after self-assembly exhibits an ordered sheet-like structure at a microscopic scale.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Screening assays for different polypeptide sequences
Using GRVGEVGRVGEVGRVGEV, SKISDISKISDISKISDI and HGFEGFHGFEGFHGFEGF, AYRSMDAYRSMDAYRSMD, HNPEQLHNPEQLHNPEQL, YKWTDIYKWTDIYKWTDI as examples respectively, preparing 20mL of 6mg/mL polypeptide aqueous solution, adding 10mL of DMEM medium containing 4.5g/L glucose, shaking and mixing uniformly, standing for 10min, then performing circular dichroism chromatography on the test polypeptide solution, freeze-drying the solution, performing scanning electron microscope observation, screening β folding conformation in the circular dichroism chromatography, and displaying a polypeptide sequence in a self-assembly form in an electron microscope picture.
Screening test for Process conditions
Using GRVGEVGRVGEVGRVGEV as an example, the following is a screening test for a coating process. 1. And screening the concentration of dopamine and the soaking time. Tests show that when the dopamine solution is lower than 1mg/mL, the coating is too thin and the adhesion is insufficient; when the dopamine solution is higher than 8mg/mL, dopamine is easy to polymerize in the solution rather than on the surface of the base material, so that raw materials are wasted, and the dopamine concentration between 1 and 8mg/mL is selected as a test condition. Through experimental exploration, the soaking time of the dopamine solution is at least 24 hours. 2. And (4) screening the concentration of the polypeptide solution and the soaking time. It was found that when the concentration of the polypeptide is less than 1mg/mL, the concentration of the polypeptide accumulated on the surface of the substrate is too low. To control costs, the maximum concentration of polypeptide solution was screened to be 8 mg/mL. Through experimental exploration, the soaking time of the polypeptide solution is at least 24 hours. 3. And (4) screening the soaking time of the DMEM medium. The DMEM soaking time is too short, so that the DMEM soaking time is not enough to induce self-assembly of all polypeptide molecules on the surface of the coating, and the anti-fouling capability of the coating is reduced. Through experimental exploration, the immersion time of the DMEM medium is at least 8 hours.
The above polypeptide sequences and preferred preparation conditions were selected to modify the surface of the substrate, as described in the following examples.
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