阅读说明：本技术 一种纳米银/氧化石墨烯/可降解聚合物的复合骨支架材料、抗菌骨支架及其制备 (Nano-silver/graphene oxide/degradable polymer composite bone scaffold material, antibacterial bone scaffold and preparation of antibacterial bone scaffold ) 是由 冯佩 帅词俊 于 2018-07-10 设计创作，主要内容包括：本发明公开了一种骨支架材料领域,具体公开了一种纳米银/氧化石墨烯/可降解聚合物的复合骨支架材料,包括可降解聚合物,以及分散在其中的表面负载有纳米银颗粒的氧化石墨烯。本发明还提供了一种抗菌骨支架,由所述的复合骨支架材料经激光3D打印得到。本发明利用氧化石墨烯和纳米银的协同抗菌和协同增强作用赋予可降解聚合物骨支架优异的抗菌功能和机械性能,可防止骨再生修复过程中的细菌感染并提供足够的机械支撑,提高骨再生修复成功率。(The invention discloses the field of bone scaffold materials, and particularly discloses a nano-silver/graphene oxide/degradable polymer composite bone scaffold material which comprises a degradable polymer and graphene oxide dispersed in the degradable polymer and loaded with nano-silver particles on the surface. The invention also provides an antibacterial bone scaffold which is obtained by laser 3D printing of the composite bone scaffold material. According to the invention, the excellent antibacterial function and mechanical property of the degradable polymer bone scaffold are endowed by utilizing the synergistic antibacterial and synergistic enhancement effects of the graphene oxide and the nano-silver, so that bacterial infection in the bone regeneration and repair process can be prevented, sufficient mechanical support is provided, and the bone regeneration and repair success rate is improved.)

1. The composite bone scaffold material of nano silver/graphene oxide/degradable polymer is characterized by comprising the degradable polymer and graphene oxide dispersed in the degradable polymer, wherein the surface of the graphene oxide is loaded with nano silver particles.

2. The nano-silver/graphene oxide/degradable polymer composite bone scaffold material according to claim 1, wherein the content of nano-silver particles in the composite bone scaffold material is 0.5-1.5 wt.%; the content of graphene oxide is 0.5-1.5 wt.%.

3. The nano-silver/graphene oxide/degradable polymer composite bone scaffold material of claim 1, wherein the nano-silver particles have a particle size of 10-50 nm:

the sheet diameter of the graphene oxide is 8-15 microns.

4. The nano-silver/graphene oxide/degradable polymer composite bone scaffold material of claim 1, wherein the degradable polymer is at least one of poly (L-lactic acid), poly (glycolic acid), poly (lactic-co-glycolic acid), polycaprolactone, poly (hydroxybutyrate-co-valerate), poly (butylene succinate);

preferably, the degradable polymer is a blend of levorotatory polylactic acid and polyglycolic acid, and further preferably the blend with the mass ratio of 1: 1;

the particle size of the degradable polymer is 10 to 100. mu.m, and more preferably 50 μm.

5. An antibacterial bone scaffold, which is obtained by laser 3D printing of the composite bone scaffold material according to any one of claims 1 to 4.

6. The antibacterial bone scaffold according to claim 5, wherein the laser power is 1-3W and the scanning speed is 100-300 mm/s, preferably 2W and 200mm/s during the laser 3D printing process.

7. The antimicrobial bone scaffold of claim 6, wherein during laser 3D printing, the scan spacing is 0.08-0.4 mm; the powder spreading thickness is 0.06-0.3 mm.

8. The method for preparing an antibacterial bone scaffold according to claim 6 or 7, comprising the steps of:

dispersing graphene oxide, nano silver and a degradable polymer in a solvent to respectively obtain a graphene oxide suspension, a nano silver suspension and a degradable polymer solution;

mixing the nano silver suspension and the graphene oxide suspension, and loading nano silver on graphene oxide to obtain a suspension of a graphene oxide-nano silver composite material;

mixing the suspension of the graphene oxide-nano silver composite material with a degradable polymer solution, and then carrying out solid-liquid separation, drying and ball milling to obtain the composite bone scaffold material powder;

and (4) placing the obtained composite bone scaffold material powder in a laser 3D printing system, and performing laser 3D printing according to the designed bone scaffold 3D model to obtain the antibacterial bone scaffold.

9. The method for preparing the antibacterial bone scaffold according to claim 8, wherein the mixing manners of the step (2) and the step (3) are magnetic stirring and ultrasonic oscillation, wherein the rotation speed of the magnetic stirring is 200 and 600 rpm;

the ultrasonic oscillation frequency is 10000-.

10. The method for preparing the antibacterial bone scaffold as claimed in claim 8, wherein the ball milling rotation speed is 100-300 rpm, and the ball-to-material ratio is 5: 1-20: 1.

Technical Field

The invention relates to an antibacterial bone scaffold containing graphene oxide and nano-silver and a preparation method thereof, belonging to the technical field of biomedical material design and preparation.

Background

Tissue engineering scaffolds play an important role in cell growth, tissue vascularization and new tissue formation as a temporary extracellular matrix, and thus it is essential to have good biological properties and suitable mechanical properties. Biodegradable polymers, such as L-polylactic acid, polyglycolic acid and poly (lactic-co-glycolic acid), have been widely used for research and development of scaffolds for bone tissue engineering due to their excellent biological properties. Although the polymer bone scaffold has good biocompatibility, biodegradability and processability, its mechanical strength is insufficient and should be increased to a degree comparable to natural bone in order to provide sufficient support during bone regeneration, and another more important aspect is that the polymer bone scaffold has no antibacterial function and is susceptible to bacterial infection after being implanted in vivo. The introduction of specific functional materials is an effective strategy to solve the problems with the polymer scaffolds described above.

Graphene oxide is a derivative of graphene that is chemically modified with carboxyl and carbonyl groups on the edges of the sheet and epoxy and hydroxyl groups on the basal planes of the sheet. Graphene oxide is attracting increasing attention due to its unique physical, chemical, and biological properties. It has extremely high strength (130 GPa) and modulus (more than 0.5-1TPa), and simultaneously, rich oxygen-containing functional groups can form hydrogen bonds with oxygen-containing functional groups of aliphatic polymers, so that good interface bonding performance is formed, and graphene oxide becomes an attractive polymer reinforcing phase. However, graphene oxide has a large specific surface area and high surface energy, and is easily agglomerated in a matrix, so that the reinforcing effect of graphene oxide is reduced. Recently, nano silver has attracted more and more attention in antibacterial applications due to its excellent antibacterial properties. The release of silver ions plays an important role in the antibacterial action, the silver ions have the highest antibacterial activity among metal ions and can attack a plurality of targets on a bacterial membrane, such as cell membranes, respiratory enzymes, proteins, DNA and the like, so that the bacteria are difficult to resist the silver ions, and meanwhile, the nano silver can promote the generation of Reactive Oxygen Species (ROS) in the bacteria to generate oxidation damage to bacterial cell components.

Disclosure of Invention

The invention provides a composite bone scaffold material of nano silver/graphene oxide/degradable polymer, aiming at solving the problems of no antibacterial function and low mechanical property of the conventional bone scaffold, and aims to provide a degradable polymer bone scaffold with synergistic effect.

The second objective of the present invention is to provide an antibacterial bone scaffold prepared from the nano-silver/graphene oxide/degradable polymer composite bone scaffold material (the present invention also provides a nano-silver/graphene oxide/degradable polymer bone scaffold).

The third purpose of the invention is to provide a preparation method of the antibacterial bone scaffold.

The graphene oxide and the nano-silver are easy to agglomerate in the degradable polymer, and the performance of the graphene oxide and the nano-silver is seriously influenced. Through a large number of researches, the inventor innovatively discovers that the nano-silver is loaded on graphene oxide in advance to obtain the nano-silver loaded graphene oxide (nano-silver/graphene oxide composite material), the nano-silver loaded graphene oxide and the nano-silver/graphene oxide composite material can synergistically avoid agglomeration of the nano-silver loaded graphene oxide and the graphene oxide through interaction of the nano-silver and the graphene oxide, and the obtained composite material can synergistically improve the mechanical property and the antibacterial property after the nano-silver loaded graphene oxide and the graphene oxide composite material are filled into a degradable polymer for compounding; therefore, the following technical scheme is provided:

a composite bone scaffold material of nano-silver/graphene oxide/degradable polymer comprises the degradable polymer and graphene oxide dispersed in the degradable polymer, wherein the surface of the graphene oxide is loaded with nano-silver particles (the material is also called nano-silver).

The composite bone scaffold material comprises a degradable polymer and graphene oxide, wherein nano silver is loaded on the graphene oxide.

According to the invention, the nano silver particles are directly loaded on the surface of the graphene oxide to prepare the nano silver/graphene oxide compound, the graphene oxide and the silver can respectively hinder the agglomeration of the opposite side and respectively promote the dispersion of the opposite side, and when the nano silver/graphene oxide compound is filled into the degradable polymer, the graphene oxide and the silver can respectively promote the dispersion of the opposite side in the degradable polymer matrix, so that the mechanical enhancement effect on the degradable polymer matrix is improved, and the mechanical property of the obtained degradable polymer composite bone scaffold is synergistically improved. In addition, the silver is loaded on the surface of the graphene oxide in advance, so that the antibacterial effects of the silver and the graphene oxide can be synergistically improved: the graphene oxide and the silver can respectively hinder agglomeration of each other and respectively promote dispersion of each other, so that respective particle size is reduced, respective specific surface area is improved, and the smaller the particle size is, the higher the specific surface area is, and the stronger the antibacterial capacity of the graphene oxide and the silver is. Moreover, the graphene oxide with negative electric energy can adsorb bacteria, and the flaky structure can wrap the bacteria, so that the contact of silver loaded on the graphene oxide with the bacteria is promoted, and the antibacterial effect of the silver on the bacteria is increased. In addition, the sharp edge of the graphene oxide can stab the cell membrane structure of bacteria, and silver ions are promoted to enter bacterial cells to generate an antibacterial effect.

Preferably, the nano silver particles have a particle size of 10 to 50 nm. Under the nanometer size, the silver particles have larger specific surface area and surface activity, thereby having stronger antibacterial activity.

Preferably, the content of the nano silver particles in the composite bone scaffold material is 0.5-1.5 wt.%. The preferable content is controlled, on one hand, good antibacterial performance can be ensured, and on the other hand, the toxic and side effects of silver can be reduced.

Preferably, the graphene oxide has a sheet diameter of 8 to 15 μm. The optimal sheet diameter is controlled, so that bacterial cells can be adsorbed more conveniently, and the wrapping performance and the antibacterial performance are improved.

Preferably, the content of the graphene oxide in the composite bone scaffold material is 0.5-1.5 wt.%. Under the control of the optimal content, the mechanical enhancement effect of the graphene oxide can be fully utilized, and the mechanical enhancement effect cannot be fully exerted due to the low content of the graphene oxide, so that the agglomeration is easily generated due to the high content of the graphene oxide, and the enhancement efficiency is reduced.

Preferably, the degradable polymer is at least one of levorotatory polylactic acid, polyglycolic acid, polylactic-co-glycolic acid, polycaprolactone, polyhydroxybutyrate valerate, polybutylene succinate and the like.

Preferably, the degradable polymer is a blend of levorotatory polylactic acid (PLLA) and polyglycolic acid (PGA), and further preferably the blend has a mass ratio of 1: 1. The blending of PLLA and PGA allows the rate of degradation of the prepared bone scaffold to match the rate of bone regeneration.

The particle size of the degradable polymer is 10 to 100. mu.m, and more preferably 50 μm.

The invention also provides an antibacterial bone scaffold which is obtained by laser 3D printing of the composite bone scaffold material.

According to the invention, the nano-silver/graphene oxide compound is prepared by fully and uniformly mixing graphene oxide and nano-silver through a certain mixing process, then the nano-silver/graphene oxide/degradable polymer bone scaffold is prepared by adding the nano-silver/graphene oxide compound into a degradable polymer and utilizing laser 3D printing, and the discovery that the graphene oxide and the nano-silver have synergistic effects in the aspects of antibiosis and mechanical enhancement can endow the degradable polymer bone scaffold with excellent antibacterial function and mechanical property, so that the bacterial infection in the bone regeneration and repair process can be prevented, sufficient mechanical support can be provided, and the bone regeneration and repair success rate can be improved.

The invention innovatively discovers that the graphene oxide and the nano-silver have synergistic effects in the aspects of dispersion, mechanical enhancement and antibiosis, and innovatively introduces the nano-silver/graphene oxide compound into the degradable polymer bone scaffold. By adopting the designed innovative nano silver/graphene oxide/degradable polymer material and performing laser 3D printing, the degradable bone scaffold with excellent antibacterial function and mechanical property can be prepared.

Preferably, in the laser 3D printing process, the laser power is 1-3W; the scanning speed is 100-300 mm/s. At this preferred optical density, the resulting antimicrobial bone scaffold performs better.

Preferably, the scanning distance is 0.08-0.4mm (preferably 0.1mm) in the laser 3D printing process; the powder spreading thickness is 0.06-0.3mm (preferably 0.1 mm).

Researches find that the nano silver/graphene oxide/degradable polymer material is used to be matched with the optimal laser 3D printing process condition in a synergistic manner, so that the bone scaffold can be formed more conveniently.

The invention also discloses a preparation method of the antibacterial bone scaffold, which comprises the following steps:

dispersing graphene oxide, nano silver particles and a degradable polymer in a solvent to respectively obtain a graphene oxide suspension, a nano silver particle suspension and a degradable polymer solution;

mixing the nano silver particle suspension and the graphene oxide suspension, and loading nano silver particles on graphene oxide to obtain a suspension of a graphene oxide-nano silver composite material;

mixing the suspension of the graphene oxide-nano silver composite material with a degradable polymer solution, and then carrying out solid-liquid separation, drying and ball milling to obtain the composite bone scaffold material powder;

and (4) placing the obtained composite bone scaffold material powder in a laser 3D printing system, and performing laser 3D printing according to the designed bone scaffold 3D model to obtain the antibacterial bone scaffold.

Through the combined action of the technical schemes of solution blending, solid-liquid separation, drying, ball milling and the like, the graphene oxide powder, the silver powder and the polymer powder are uniformly mixed, and the performance of the obtained compound can be further improved.

In the step (1), the solvent is absolute ethyl alcohol.

Preferably, in the preparation method, the mixing manners of the step (2) and the step (3) are magnetic stirring and ultrasonic oscillation, wherein the magnetic stirring rotation speed is preferably 200-600 rpm, and the time is preferably 1-3 hours. The ultrasonic oscillation frequency is 10000-100000Hz (preferably 40000Hz), the ultrasonic power is 120-800W (preferably 480W, and the ultrasonic time is preferably 1-3 hours.

Preferably, the drying is carried out under vacuum, wherein the drying temperature is 50 to 70 ℃, preferably 60 ℃.

The ball milling speed is 100-300 r/min, the ball milling time is 3-6 h, and the ball-material ratio is 5: 1-20: 1 (preferably 10: 1).

The invention discloses a preparation method of a preferable antibacterial bone scaffold, which comprises the following steps:

step one

Respectively weighing nano-silver powder, graphene oxide powder and degradable polymer powder according to component design, respectively adding the nano-silver powder, the graphene oxide powder and the degradable polymer powder into absolute ethyl alcohol, respectively magnetically stirring for 1-3 hours at 200-600 r/min, and then ultrasonically oscillating for 1-3 hours at 10000-100000HzHz and 120-800W to respectively obtain nano-silver suspension, graphene oxide suspension and degradable polymer suspension; adding the nano-silver suspension into the graphene oxide suspension, magnetically stirring for 1-3 hours at 600 revolutions per minute under 200-; adding the nano silver/graphene oxide mixed suspension into the degradable polymer suspension, magnetically stirring for 1-3 hours at 200-; filtering the nano silver/graphene oxide/degradable polymer mixed suspension and leaving a precipitate; drying the precipitate at 50-70 ℃ for 48h in vacuum until the weight is constant to obtain nano silver/graphene oxide/degradable polymer mixed powder; ball-milling the nano-silver/graphene oxide/degradable polymer mixed powder at the rotation speed of 100-300 r/min for 3-6 hours and at the ball-to-material ratio of 5: 1-20: 1 to obtain the nano-silver/graphene oxide/degradable polymer mixed powder for laser 3D printing;

step two

Preparing a degradable polymer bone scaffold (abbreviated as nano silver/graphene oxide/degradable polymer bone scaffold) containing nano silver and graphene oxide by using the nano silver/graphene oxide/degradable polymer mixed powder obtained in the step one as a raw material and adopting a laser 3D printing technology under a protective atmosphere; in the preparation process, the laser power is controlled to be 1-3W; the scanning speed is 100-300 mm/s; the scanning interval is 0.08-0.4 mm; the powder spreading thickness is 0.06-0.3 mm.

The average particle diameter of the degradable polymer powder is 10-100 μm, preferably 40-60 μm; the average sheet diameter of the graphene oxide powder is 8-15 μm; the average grain diameter of the nano silver powder is 10-50 nm.

The protective atmosphere is high-purity argon atmosphere, and the purity of the argon is more than or equal to 99.999 percent.

In the invention, the nano-silver-loaded graphene oxide (nano-silver/graphene oxide composite material) is provided, wherein nano-silver particles are loaded on the graphene oxide nanosheets, and the nano-silver particles are inserted into the graphene oxide lamella, so that the aggregation of the graphene oxide nanosheets is prevented, the dispersion of the graphene oxide nanosheets is further promoted, the efficiency of mechanical enhancement can be effectively improved, and the synergistic enhancement effect is achieved. And the graphene oxide is a flaky carbon nano material with the characteristics of rich oxygen-containing functional groups, large pi conjugated structure, high specific surface area, surface negative charge and the like, can interact with cell membrane components of bacteria to be adsorbed on the bacteria, and the nano silver particles are loaded on the graphene oxide nano sheet to increase the contact with the bacteria, so that more killing effects on the bacteria are generated, and a synergistic antibacterial effect is obtained. The nano-silver/graphene oxide compound is innovatively introduced into the degradable polymer, and the nano-silver/graphene oxide degradable polymer composite bone scaffold is prepared by adopting a laser 3D printing technology, has excellent antibacterial function and mechanical property, is expected to prevent bacterial infection in the bone regeneration and repair process, provides sufficient mechanical support and improves the bone regeneration and repair success rate.

In the nano-silver/graphene oxide/degradable polymer bone scaffold designed and prepared by the invention, a proper amount of nano-silver and graphene oxide have a synergistic dispersion effect in a degradable polymer matrix, and the synergistic dispersion effect is that nano-silver particles are loaded by using graphene oxide nanosheets and are inserted into graphene oxide lamella layers, so that respective aggregation is mutually hindered, and uniform dispersion is realized.

In the nano-silver/graphene oxide/degradable polymer bone scaffold designed and prepared by the invention, a proper amount of nano-silver and graphene oxide have a synergistic enhancement effect so as to have the effect of improving the mechanical property of the bone scaffold, and the synergistic enhancement effect is realized by promoting the transfer efficiency of stress in a degradable polymer matrix and avoiding stress concentration by utilizing the synergistic dispersion effect of the nano-silver and the graphene oxide in the degradable polymer matrix.

In the nano-silver/graphene oxide/degradable polymer bone scaffold designed and prepared by the invention, a proper amount of nano-silver and graphene oxide have a synergistic antibacterial effect so as to endow the bone scaffold with an excellent antibacterial function, and the synergistic antibacterial effect is realized by utilizing the graphene oxide nanosheets to adsorb and wrap bacteria, promoting the contact of the nano-silver loaded on the graphene oxide nanosheets, silver ions generated by the nano-silver and Reactive Oxygen Species (ROS) with the bacteria and further generating a more killing effect on the bacteria.

The nano-silver/graphene oxide/degradable polymer bone scaffold designed and prepared by the invention has excellent antibacterial function and mechanical property, can prevent bacterial infection in the bone regeneration and repair process and provide sufficient mechanical support, improves the bone regeneration and repair success rate, and has obvious advantages when being used as a bone implant.

Principles and advantages

According to the invention, through a series of processes such as solution blending, magnetic stirring, ultrasonic oscillation, vacuum drying, mechanical ball milling and the like and optimization of process parameters, the uniform mixing of nano-silver powder, graphene oxide powder and degradable polymer powder is realized; this provides the necessary condition for the even dispersion of nano-silver and graphene oxide in the degradable polymer matrix. And then preparing the nano silver/graphene oxide/degradable polymer bone scaffold with excellent antibacterial function and mechanical property by using the nano silver/graphene oxide/degradable polymer mixed powder and utilizing a laser 3D printing technology and optimizing process parameters.

Compared with the prior art, the invention has the following advantages:

(1) by adopting the powder mixing series process provided by the invention, the prepared nano silver/graphene oxide/degradable polymer mixed powder has high uniformity.

(2) By adopting the laser 3D printing process parameters provided by the invention, the prepared nano silver/graphene oxide/degradable polymer bone scaffold has a customizable appearance and an interconnected and through internal porous structure.

(3) By adopting the material component design provided by the invention, the problem of agglomeration of GO and Ag is solved, the synergistic effect of GO and Ag is utilized, and the prepared nano silver/graphene oxide/degradable polymer bone scaffold has excellent antibacterial function and mechanical property and good biocompatibility.

Detailed Description

The following examples illustrate specific embodiments of the present invention: