CN113881992A

CN113881992A - A new type of coated medical porous zinc material and preparation method thereof

Info

Publication number: CN113881992A
Application number: CN202111153818.3A
Authority: CN
Inventors: 顾雪楠; 王一凡; 汤红艳; 陈凯; 樊瑜波
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2022-01-04
Anticipated expiration: 2041-09-29
Also published as: CN113881992B

Abstract

The invention discloses a novel coated medical porous zinc material and a preparation method thereof. The preparation steps mainly include: degreasing, roughening and film removal and conducting treatment of a porous template in sequence, and then using it as a cathode, pure zinc The plate is used as the anode, the DC power supply is connected, and the constant current electrodeposition is carried out in the zinc sulfate electroplating solution. After a certain thickness of zinc layer is uniformly deposited on the surface of the template, it is placed in a vacuum resistance furnace for sintering treatment to remove the template, and the sintering treatment is used to obtain The porous zinc is hydrothermally reacted in the hydrothermal kettle of the coating reaction solution, and a uniform coating is supported on its surface. The porous zinc prepared by the invention has a uniform and interconnected pore size, has a porosity of more than 95%, and has good biocompatibility, is suitable for the field of tissue engineering scaffolds such as bone defect filling and repair, and has broad application prospects.

Description

Novel coated medical porous zinc material and preparation method thereof

Technical Field

The invention relates to a novel coated medical porous zinc material and a preparation method thereof. The material has a structure similar to that of cancellous bone, the holes are communicated with each other, the porosity is high, capillary vessels can be formed in the material, various nutrients can be provided for bone regeneration, the material has good biocompatibility, the bone regeneration can be induced, and the material belongs to the technical field of biomedical metal material design and preparation.

Background

The porous metal material is also called foam metal, is a multifunctional material with excellent performance, is widely applied to the fields of automobiles, environmental protection, aerospace and the like, and also shows great application prospect in the field of biomedical implant materials. The traditional processed metal implant can generate stress shielding effect due to mismatching of elastic modulus and bone in vivo, so that the implant fails prematurely, and the biomedical porous metal can reduce the strength and elastic modulus of the material by controlling the aperture and porosity, and improve the biomechanical compatibility so that the biomedical porous metal is matched with bone tissues better. In addition, the pores of the open porous metal are communicated with each other to form a channel, which is beneficial to the transmission of body fluid and nutrient substances in the material and further promotes the regeneration and repair of bone tissues.

At present, people mainly focus on inert metals such as stainless steel, titanium alloy, tantalum, cobalt-chromium alloy and the like for research on medical porous metals. However, these non-biodegradable materials all cause chronic local inflammation and physiological irritation, and removal by secondary surgery is unavoidable. In recent years, there has been an increasing interest in the use of biodegradable metals in biomedicine. The inherent strength and ductility of the degradable metal can ensure that the degradable metal is applied to the repair of hard tissues such as bones, and the like, and the biodegradability can also ensure that patients can be prevented from suffering from secondary taking-out operations. The most widely studied degradable metals include magnesium, iron, zinc and their alloys, among which zinc exhibits a more favorable degradation rate than magnesium and iron, and its degradation products are completely bioabsorbable without releasing excessive hydrogen. And as a trace element necessary for a human body, zinc not only can promote osteogenesis and inhibit bone tissue loss and inflammation-related diseases, but also plays an important role in cartilage matrix metabolism (SOX9) and cartilage II gene expression, and the medical porous metal prepared by adopting pure zinc is expected to become a new-generation bone implant material.

The method for preparing the porous metal mainly comprises a sintering method, a powder metallurgy method, a seepage casting method and the like. The methods generally have the problems of poor pore connectivity, low porosity and the like, and are difficult to be used for preparing medical porous zinc with higher requirement on pore structure.

Furthermore, the biocompatibility of pure zinc depends on the concentration of zinc ions in vivo, i.e., low concentrations of zinc ions are beneficial to cells, while high concentrations of zinc ions are harmful to cells. The directly prepared pure zinc porous material can bring the risk of rapid release of zinc ions while the specific surface area is increased, and the loading of a coating with excellent biocompatibility on the surface is an effective method for solving the problem. An organic metal framework (MOFs) is a crystal material formed by self-assembling an organic ligand and metal ions through coordination bonds, has the advantages of high specific surface area, high porosity, easy functionalization and the like, and has wide application prospects in the field of biomedicine. Bioactive metal elements can be loaded on the surface of the porous zinc through the MOFs coating, so that the biocompatibility and the biological functionality of the material are improved. Magnesium is a necessary nutrient element for human bodies, has excellent biocompatibility and can promote the regeneration of bone tissues, and magnesium-based MOFs materials are also MOFs materials with mature preparation processes.

The porous zinc material which has the structure similar to that of bone tissue, the mutual communication of pores, high porosity and good biocompatibility and biological functionality is prepared at present, and has important significance for repairing and treating bone defects.

Disclosure of Invention

The invention aims to prepare a biomedical porous zinc material, the porous zinc in the invention has highly communicated three-dimensional through holes, high porosity and uniform structure, and meanwhile, the Cu-Mg-based coating is loaded on the surface of the porous zinc, so that the biocompatibility of the material is improved, the material has certain biological functionality, and the bone regeneration can be promoted.

The invention relates to a preparation method of a novel coated medical porous zinc material, which comprises the following steps:

step one, template pretreatment;

step 11, sample preparation;

cutting the polyurethane sponge into the size of required size (length multiplied by width, 50mm multiplied by 50mm) to form a first sample;

the pore diameter of the polyurethane sponge sample is 40PPI, 50PPI and 60 PPI.

Step 12, preparing chemical degreasing fluid;

20-40 g of NaOH and Na are needed in 1L of chemical degreasing solution₂20-30 g of CO and Na₃PO₄5-10 g of OP emulsifier, 0.5-1.0 ml of OP emulsifier and the balance of deionized water.

The pH value of the degreasing fluid is kept between 10 and 12.

Step 13, degreasing the organic solvent;

immersing the first sample into absolute ethyl alcohol, repeatedly extruding and stirring for 10-60 s for organic solvent degreasing, taking out, and washing with distilled water for 5-10 minutes to obtain a second sample;

step 14, chemical degreasing treatment;

immersing the second sample into the chemical degreasing solution prepared in the step 12, repeatedly extruding and stirring for 5-10 minutes for chemical degreasing, taking out the second sample, and washing the second sample with distilled water for 5-10 minutes to obtain a third sample;

step two, coarsening and membrane removing treatment;

step 21, preparing a roughening solution;

KMnO required for preparing 1L of coarsening solution₄0.5 to 1.0g, H₂SO₄0.03-0.06 ml and the balance of deionized water.

The pH value of the coarsening solution is kept between 2 and 3.

Step 22, preparing a membrane removing solution;

preparation of 1L of the desired C for the membrane removal solution₂H₂O₄The oxalic acid is 5-10 g and the balance of deionized water.

Step 23, coarsening;

heating the coarsening solution to 45 ℃, then immersing the third sample into the heated coarsening solution, repeatedly extruding and stirring for 5-10 minutes for coarsening, taking out, and washing with distilled water for 5-10 minutes to obtain a fourth sample;

step 24, membrane removal treatment;

heating the film removing solution to 55 ℃, then immersing the fourth sample into the heated film removing solution, repeatedly extruding and stirring for 5-10 minutes to carry out hot film removal, taking out, washing with distilled water for 5-10 minutes, and airing to obtain a fifth sample;

conducting treatment;

fully and uniformly coating the graphite conductive adhesive on the fifth sample to obtain a sixth sample;

curing the sixth sample in a vacuum drying oven or naturally curing the sixth sample at room temperature to obtain a seventh sample;

the curing temperature in a vacuum drying oven is 60-90 ℃, and the curing time is 1-2 h;

the natural curing time at room temperature of 25 ℃ is 24 h.

Step four, preparing a zinc layer by electrodeposition;

step 41, preparing sulfate electrogalvanizing liquid;

preparing 1L of ZnSO required by sulfate electroplating solution₄200 to 250g of Al₂(SO₄)₃15 to 20g of KAl (SO)₄)₂35 to 45g of Na₂SO₄20-30 g and the balance of deionized water.

The pH value of the sulfate electroplating solution is kept between 3 and 4;

step 42, performing electrodeposition by adopting a constant current method;

guiding the sulfate electrogalvanizing solution obtained in the step 41 into a deposition tank, placing the deposition tank on a constant-temperature water bath stirring device, and placing magnetons into an electrodeposition tank for stirring; setting the rotating speed of a magnetic stirrer to be 400-600 r/min, and the temperature of the plating solution to be 25-40 ℃;

taking the seventh sample as a cathode, and fixing two sides of the cathode by hollow copper sheets;

two 5mm pure zinc plates are used as double anodes and are placed on two sides of a cathode;

performing electrodeposition by adopting a constant current method, wherein the current density is 0.04-0.08A/mm²Depositing for 1-2 hours, adding additives in a deposition period according to the consumption rate of 0.3 mL/A.H, cleaning with distilled water after electrodeposition, and airing to prepare zinc with a porous structure, namely an eighth sample;

in the invention, the additive comprises a brightener and a softener, in particular to a CT-1 type brightener and a CT-1 type softener produced by limited chemical companies of Jiangsu Mengde electroplating chemicals.

In the invention, the current density is set to be 0.04-0.08A/mm²The apparent current density was obtained based on the apparent area of the seventh sample exposed to the plating solution.

Step five, sintering treatment;

the eighth sample is packaged in a vacuum mode by a quartz tube and is placed in a sintering furnace;

adjusting the sintering temperature to 300-350 ℃, the sintering temperature rise speed to 5-10 ℃/min, and the sintering time to 1-2 h; and cooling the sample to 25-40 ℃ along with the furnace after the sample is sintered, and taking out the sample to obtain a ninth sample.

Step six, coating loading;

step 61, preparing a reaction solution;

the concentration of the reaction solution is 1.5-3 mmol of solute added in each 70mL of solvent.

The solute is an organic ligand and a metal salt in a molar ratio of 3: 1. The organic ligand is preferably 2, 5-dihydroxyterephthalic acid (DHTA). The metal salt is magnesium nitrate or a combination of magnesium nitrate and copper nitrate.

The solvent is N, N-Dimethylformamide (DMF), water and ethanol in a volume ratio of 15:1: 1.

Step 62, carrying out hydrothermal reaction;

and vertically suspending the ninth sample in a polytetrafluoroethylene inner lining of a hydrothermal kettle, adding the reaction solution, putting the hydrothermal kettle into an oven for hydrothermal reaction, cooling to 25-40 ℃, and taking out to obtain a tenth sample.

The hydrothermal reaction temperature is 120-125 ℃, and the reaction time is 4-8 h.

Step 63, post-processing;

and (3) soaking the tenth sample in DMF for 10-30 min to remove unreacted solvent, and then washing with methanol to remove DMF to obtain an eleventh sample.

And (3) drying the eleventh sample in an oven at the temperature of 60-80 ℃ for 10-40 minutes, and taking out to obtain a twelfth sample.

Compared with the prior art, the coated biomedical porous zinc material has the following advantages:

firstly, most of the existing methods for preparing medical porous zinc are a seepage casting method and a powder metallurgy method, and CN 107354335A discloses a method and a device for preparing medical open-cell foam zinc materials, wherein the method comprises the steps of sintering a calcium chloride preform, placing metal zinc in a vacuum seepage device for temperature rise and pressure rise to carry out seepage casting, and removing preform particles by water dissolution, wherein the porosity of the porous zinc material obtained by the method is 59-70%; CN 110449584A discloses a method for preparing medical degradable open-cell foam zinc, which comprises the steps of mixing zinc powder and a pore-forming agent, carrying out pressure sintering in a mould, and removing the pore-forming agent through water dissolution, wherein the porosity of the open-cell foam zinc obtained by the method is 40-78%, and the pore diameter is 0.8-2 mm. The two disclosed preparation methods of the porous zinc have the advantages of low porosity, large pore diameter, difficulty in control, incapability of ensuring uniform distribution and connectivity of internal pores, and existence of partially closed pores. The invention adopts an electrodeposition method and takes polyurethane as a template, the prepared porous zinc has uniform pore size distribution and high porosity, and the problems of low porosity and non-uniform pore size in the prior art are solved. In addition, the pore diameter and porosity of the porous zinc can be adjusted by replacing different polyurethane sponge matrixes.

Secondly, the invention adopts nontoxic and environment-friendly zinc sulfate salt as the main component of the electroplating solution, and can obtain an open porous zinc structure with uniform plating layer, smooth and complete surface by controlling the current density and the deposition time and adjusting the proportion of the electroplating solution.

The porous zinc prepared by the invention has highly communicated open pores, has a structure similar to that of cancellous bone, is favorable for forming a capillary network in the porous zinc, promotes the transportation of body fluid and nutrient substances, and reduces the risk of necrosis of the central part of the bone defect due to ischemia.

The Mg-based MOFs coating loaded on the surface of the porous zinc prepared by the invention can improve the biocompatibility of the material and promote the bone regeneration of the defect part, and bioactive metal elements such as copper ions with antibacterial and vascularization promoting effects are added on the basis, so that the material has multiple biological functions.

Therefore, compared with the prior art, the invention can prepare the medical open-pore porous zinc material with high porosity and high connectivity, has good biocompatibility and has wide application prospect in the field of tissue engineering scaffolds for bone defect filling repair and the like.

Drawings

Fig. 1 is a scanning electron microscope image of the porous zinc material prepared to the end of step five in example 1 of the present invention, in which it can be observed that the material is in a three-dimensional network structure, the internal pores are uniform and connected, the average diameter of the pores is 0.51mm, and the porosity is 97%.

FIG. 2 is a scanning electron microscope image of the coated porous zinc material prepared in example 1 of the present invention, wherein the porous zinc surface is covered with a dense Cu-Mg-based coating.

FIG. 3 is an interface scanning electron microscope image of the coating of the coated porous zinc prepared in example 1 of the present invention, wherein the coating structure is a closely packed spherical structure, and the average thickness of the coating is 30 μm.

Fig. 3A is a scanning electron microscope image of a test point of the coating interface of the coated porous zinc prepared in example 1 of the present invention.

FIG. 4 is an XRD diffraction pattern of the coated porous zinc surface coating prepared in example 1 of the present invention, the material surface coating is consistent with the characteristic peak-to-peak value of standard Mg-MOF-74, indicating that the sample surface coating composition is mainly Mg-MOF-74.

FIG. 5 shows the cytotoxicity test results of the coated porous zinc in example 1 of the present invention on MC3T3-E1, and the cytotoxicity of the test sample is significantly reduced and the biocompatibility is improved compared with that of the pure zinc material.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Example 1

Step one, template pretreatment;

step 11, sample preparation;

cutting 50PPI polyurethane sponge into a length of 50mm and a width of 50mm to obtain a first sample;

step 12, preparing chemical degreasing fluid;

35g of NaOH and Na are needed in 1L of chemical degreasing solution₂CO is 25g and Na₃PO₄10g of OP emulsifier, 0.5ml of OP emulsifier and the balance of deionized water.

The pH value of the degreasing fluid is kept between 10 and 12.

Step 13, degreasing the organic solvent;

immersing the first sample into absolute ethyl alcohol, repeatedly extruding and stirring for 60s for organic solvent degreasing, taking out, and washing with distilled water for 5 minutes to obtain a second sample;

step 14, chemical degreasing treatment;

immersing the second sample into the chemical degreasing solution prepared in the step 12, repeatedly extruding and stirring for 5 minutes for chemical degreasing, taking out the second sample, and washing the second sample with distilled water for 5 minutes to obtain a third sample;

step two, coarsening and membrane removing treatment;

step 21, preparing a roughening solution;

KMnO required for preparing 1L of coarsening solution₄Is 1g, H₂SO₄0.05ml and the balance deionized water.

The pH value of the coarsening solution is kept between 2 and 3.

Step 22, preparing a membrane removing solution;

preparation of 1L of the desired C for the membrane removal solution₂H₂O₄Oxalic acid 10g and the balance deionized water.

Step 23, coarsening;

heating the coarsening solution to 45 ℃, then immersing the third sample into the heated coarsening solution, repeatedly extruding and stirring for 5 minutes for coarsening, taking out, and washing with distilled water for 5 minutes to obtain a fourth sample;

step 24, membrane removal treatment;

heating the membrane removing solution to 55 ℃, then immersing the fourth sample into the heated membrane removing solution, repeatedly extruding and stirring for 5 minutes to carry out hot membrane removal, taking out, washing with distilled water for 5 minutes, and then airing to obtain a fifth sample;

conducting treatment;

curing the sixth sample in a vacuum drying oven to obtain a seventh sample;

the curing temperature in the vacuum drying oven is 60 ℃, and the curing time is 1 h;

step four, preparing a zinc layer by electrodeposition;

step 41, preparing sulfate electrogalvanizing liquid;

preparing 1L of ZnSO required by sulfate electroplating solution₄250g of Al₂(SO₄)₃Is 20g, KAl (SO)₄)₂45g of Na₂SO₄30g and balance deionized water.

The pH value of the sulfate electroplating solution is kept between 3 and 4;

step 42, performing electrodeposition by adopting a constant current method;

guiding the sulfate electrogalvanizing solution obtained in the step 41 into a deposition tank, placing the deposition tank on a constant-temperature water bath stirring device, and placing magnetons into an electrodeposition tank for stirring; setting the rotation speed of a magnetic stirrer at 600r/min, the temperature of the plating solution at 35 ℃ and the current density at 0.040A/cm²The deposition time is 1.5 h;

taking the seventh sample as a cathode, fixing two sides of the seventh sample by hollow copper sheets, wherein the exposed area of each side of each copper sheet is 16cm²；

Two pure zinc plates with the diameter of 5mm are used as double anodes and are placed on two sides of a cathode, and the cross section of each zinc plate is a square thin plate with the diameter of 50mm multiplied by 50 mm;

in the present invention, electrodeposition was carried out by a constant current method with a set current density of 0.040A/mm²The zinc plating additive (1mL/L brightener and 15mL/L softener) is added in portions according to the consumption rate of 0.3 mL/A.H during the deposition, and after the electrodeposition, the zinc plating additive is washed by distilled water and dried to prepare porous zinc, namely an eighth sample.

CT-1 type brightener and CT-1 type softening agent produced by Jiangsu Mengde electroplating chemical company Limited are selected.

In the present invention, the current density was set to 0.04A/cm²The apparent current density was obtained based on the apparent area of the seventh sample exposed to the plating solution.

Step five, sintering treatment;

and adjusting the sintering temperature to 300 ℃, the sintering temperature rise speed to 5 ℃/min, the sintering time to 1.5h, cooling to 30 ℃ in the furnace along with the furnace after sintering, and taking out to obtain a ninth sample.

Referring to fig. 1, an environmental scanning electron microscope is used to perform morphology analysis on the ninth sample, and it can be observed that the ninth sample has three-dimensionally connected pore channels, and the interior of the skeleton is a hollow structure.

Step six, coating loading;

step 61, preparing a reaction solution;

the concentration of the reaction solution was 3mmol of solute per 70mL of the solvent.

The solutes were 639mg of magnesium nitrate hexahydrate, 1mg of copper nitrate hexahydrate and 160mg of DHTA (2, 5-dihydroxyterephthalic acid).

The solvent was 60mL of DMF to which were added 4mL of deionized water and 4mL of absolute ethanol, respectively.

Step 62, carrying out hydrothermal reaction;

and vertically suspending the ninth sample in a polytetrafluoroethylene inner lining of a hydrothermal kettle, adding the reaction solution, putting the hydrothermal kettle into an oven for hydrothermal reaction, cooling to 30 ℃, and taking out to obtain a tenth sample.

The hydrothermal reaction temperature is 120 ℃, and the reaction time is 4 h.

Step 63, post-processing;

the tenth sample was immersed in DMF for 10min to remove unreacted solvent, and then washed with methanol to remove DMF, to obtain an eleventh sample.

The eleventh sample was dried in an oven at 60 ℃ for 20 minutes and then taken out to obtain a twelfth sample.

Referring to fig. 2, an environmental scanning electron microscope is used to perform morphology analysis on the twelfth sample, and it can be observed that the twelfth sample has three-dimensionally connected pore channels, the interior of the porous skeleton is of a hollow structure, the porosity is more than 95%, the average pore diameter is 0.51mm, and the distribution is uniform.

Referring to fig. 3 and 3A, the twelfth sample was analyzed for morphology using an environmental scanning electron microscope, and it was observed that the surface of the porous skeleton was coated with a layer of coating having an average thickness of 30 μm.

Referring to fig. 4 (diffraction angle on abscissa and relative intensity on ordinate), the twelfth sample was subjected to composition analysis, the surface coating of the sample was scraped off, and the phase analysis of the coating powder was performed using an X-ray diffractometer under the following test conditions: cu Ka radiation; x-ray generator power: 2.2kW, a scanning range of 5-50 degrees and a scanning speed of 5 degrees/min. The XRD pattern shows that the characteristic peak of the twelfth sample is consistent with the peak value of the characteristic peak in the standard XRD pattern of Mg-MOF-74, which indicates that the surface coating component of the twelfth sample is mainly Mg-MOF-74.

Soaking surface area 2cm with 5mL of serum free Hepes free alpha-MEM medium²The sample is prepared into leaching liquor, and after leaching is carried out for 72 hours in an incubator at 37 ℃, the leaching liquor is taken out and stored in a 15mL centrifuge tube in a super clean bench. Cytotoxicity assay was carried out using Cell Counting Kit-8 Kit, wherein MC3T3-E1 cells with good growth status were seeded in 96-well plate at a density of 100. mu.L per 3000 cells per well, and CO was incubated at 37 ℃ in a 96-well plate₂Culturing in incubator for 1 day to allow cell to adhere to wall, sucking out old culture medium, adding 100 μ L of α -MEM complete culture medium with volume ratio of 50%, 25%, 10% to positive control group, adding 100 μ L of α -MEM to negative control group, culturing for 2 days, taking out old culture medium, adding 100 μ L of α -MEM culture medium containing 10% CCK8 per well, culturing at 37 deg.C in CO at 37 deg.C₂And (5) incubating in an incubator for 1h, measuring the absorbance value of each hole under 450nm by using a microplate reader, and calculating the cell activity. Referring to fig. 5 (the abscissa is different coating materials, and the ordinate is cell viability), cytotoxicity analysis is performed on the twelfth sample, and it can be seen that compared with the pure zinc material, the twelfth sample has improved cell viability under the condition of culturing with different concentrations of leaching liquor, and has improved cell viability to more than 80% under the condition of culturing with 25% of leaching liquor, so that cytotoxicity is obviously reduced, and biocompatibility is improved.

The main instruments required for the analysis of the sample properties are shown in table 1:

TABLE 1 Main instruments used in the experiment

The main reagents required for the performance analysis of the samples are shown in table 2:

TABLE 2 Main reagents used in the experiment

Experimental reagent	Production company
		MEM Alpha Medium	American Saimer Feishale Gibco
0.25% Trypsin	American Saimer Feishale Gibco
		Fetal bovine serum	American Saimer Feishale Gibco
Cell counting kit-8 kit	Dojindo chemical research of Japan
		Phosphate Buffer Solution (PBS)	BEIJING SOLARBIO TECHNOLOGY Co.,Ltd.

Example 2

Example 2 differs from example 1 in that:

step one, template pretreatment;

the pore diameter of the polyurethane sponge selected in the step 11 is 40 PPI;

step four, preparing a zinc layer by electrodeposition;

the temperature of the plating solution in the step 42 is 30 ℃, and the deposition time is 1 h;

step five, sintering treatment;

and 5, setting the sintering time in the fifth step to be 1 h.

Step six, coating loading;

step 61, preparing a reaction solution;

The solutes were 640mg of magnesium nitrate hexahydrate and 160mg of DHTA.

Step 62, carrying out hydrothermal reaction;

and vertically suspending the ninth sample in a polytetrafluoroethylene inner lining of a hydrothermal kettle, adding the reaction solution, putting the hydrothermal kettle into an oven for hydrothermal reaction, cooling to 40 ℃, and taking out to obtain a tenth sample.

The hydrothermal reaction temperature is 125 ℃, and the reaction time is 6 h.

Performance analysis

The porous zinc material prepared by the method of the embodiment 2 has three-dimensionally communicated pore channels, the interior of the porous framework is of a hollow structure, the porosity is more than 95%, the average pore diameter is 0.64mm, the porous framework is uniformly distributed, and the surface of the porous framework is wrapped by a coating layer with the average thickness of 30 microns.

Example 3

Example 3 differs from example 1 in that:

step one, template pretreatment;

the pore diameter of the polyurethane sponge selected in the step 11 is 60 PPI;

step four, preparing a zinc layer by electrodeposition;

the temperature of the plating solution in the step 42 is controlled to be 40 ℃, and the deposition time is 1 h;

step five, sintering treatment;

and (5) keeping the sintering heat preservation time in the fifth step for 2 hours.

Step six, coating loading;

step 61, preparing a reaction solution;

The solute was 638mg magnesium nitrate hexahydrate, 2mg copper nitrate hexahydrate and 160mg DHTA.

Performance analysis

The porous zinc material prepared by the method in the embodiment 3 has three-dimensionally communicated pore channels, the interior of the porous framework is of a hollow structure, the porosity is more than 95%, the average pore diameter is 0.42mm, the porous framework is uniformly distributed, and the surface of the porous framework is wrapped by a coating with the average thickness of 20 microns.

Example 4

Example 4 differs from example 1 in that:

step one, template pretreatment;

the pore diameter of the polyurethane sponge selected in the step 11 is 60 PPI;

step four, preparing a zinc layer by electrodeposition;

the temperature of the plating solution in the step 42 is 25 ℃, and the constant current density during deposition is 0.06A/cm²，；

Step five, sintering treatment;

Step six, coating loading;

step 61, preparing a reaction solution;

The solutes were 637mg of magnesium nitrate hexahydrate, 3mg of copper nitrate hexahydrate and 160mg of DHTA.

Performance analysis

The surface of the porous zinc material framework prepared in the embodiment 4 is wrapped by a layer of coating with the average thickness of 20 micrometers, the whole framework still has three-dimensional communicated pore channels, the interior of the porous framework is of a hollow structure, the porosity is more than 95%, the average pore diameter is 0.42mm, and the porous framework is uniformly distributed.

Claims

1. a preparation method of novel coating medical porous zinc material is characterized in that comprising the following steps:

Step 1, template preprocessing;

Step 11, sample preparation;

Cut the polyurethane sponge to the required size to become the first sample;

The pore size of the polyurethane sponge sample is 40PPI, 50PPI, or 60PPI;

Step 12, prepare chemical degreasing solution;

In preparing 1L of chemical degreasing solution, the required NaOH is 20-40g, Na ₂ CO is 20-30g, Na ₃ PO ₄ is 5-10g, OP emulsifier is 0.5-1.0ml and the balance is deionized water;

The pH value of the degreasing solution is kept between 10 and 12;

Step 13, degreasing treatment of organic solvent;

Immerse the first sample in anhydrous ethanol and repeatedly squeeze and stir for 10-60 s to degrease the organic solvent. After taking out, rinse with distilled water for 5-10 minutes to obtain the second sample;

Step 14, chemical degreasing treatment;

Immerse the second sample in the chemical degreasing solution obtained in step 12, repeatedly squeeze and stir for 5-10 minutes to carry out chemical degreasing, take out and rinse with distilled water for 5-10 minutes to obtain a third sample;

Step 2, roughening-film removal treatment;

Step 21, preparing a coarsening solution;

The KMnO ₄ required to prepare 1L of the coarsening solution is 0.5-1.0 g, the H ₂ SO ₄ is 0.03-0.06 ml and the balance of deionized water;

The pH value of the coarsening solution is kept between 2 and 3;

Step 22, preparing a film removal solution;

The oxalic acid required to prepare 1L of film removal solution is 5-10g and the balance of deionized water;

Step 23, coarsening;

The roughening solution is heated to 45°C, and then the third sample is immersed in the heated roughening solution, and the fourth sample is obtained by repeatedly pressing and stirring for 5-10 minutes for roughening, and then washing with distilled water for 5-10 minutes after taking it out. Sample;

Step 24, film removal treatment;

Heat the film removal solution to 55°C, then immerse the fourth sample in the heated film removal solution, repeatedly squeeze and stir for 5 to 10 minutes for thermal film removal, take out and rinse with distilled water for 5 to 10 minutes, and then air dry , the fifth sample is obtained;

Step 3, conductive treatment;

Fully spread the graphite conductive adhesive on the fifth sample to obtain the sixth sample;

The sixth sample is cured in a vacuum drying oven or naturally cured at room temperature to obtain the seventh sample;

The curing temperature in the vacuum drying oven is 60℃～90℃, and the curing time is 1～2h;

The natural curing time is 24h at room temperature of 25℃;

Step 4, electrodepositing the zinc layer;

Step 41, preparing sulfate electro-galvanizing solution;

The required ZnSO ₄ for preparing 1 L of sulfate electroplating solution is 200-250 g, Al ₂ (SO ₄ ) ₃ is 15-20 g, KAl(SO ₄ ) ₂ is 35-45 g, Na ₂ SO ₄ is 20-30 g and the balance of deionized water;

The pH value of the sulfate electroplating solution is kept between 3 and 4;

Step 42, using a constant current method for electrodeposition;

The sulfate electro-galvanizing solution obtained in step 41 is introduced into the deposition tank, the deposition tank is placed on the constant temperature water bath stirring device, and the magnetron is placed in the electrodeposition tank for stirring; The liquid temperature is 25℃～40℃;

The seventh sample is used as the cathode, and the two sides are fixed with hollow copper sheets;

Two 5mm pure zinc plates are used as double anodes and placed on both sides of the cathode;

Electrodeposition was carried out by constant current method, the current density was 0.04-0.08A/mm ² , and the deposition time was 1-2 hours. During the deposition, the additive was added in stages with reference to the consumption rate of 0.3mL/A·H, and washed with distilled water after electrodeposition. And air-dry to obtain zinc with porous structure, namely the eighth sample;

Step 5, sintering treatment;

The eighth sample is vacuum-sealed with a quartz tube and placed in a sintering furnace;

Adjust the sintering temperature to be 300°C to 350°C, the sintering heating rate to be 5 to 10°C/min, and the sintering time to be 1 to 2 hours; after the sample is sintered, it is cooled to 25°C to 40°C in the furnace and then taken out to obtain the ninth sample;

Step 6, coating load;

Step 61, preparing a reaction solution;

The concentration of the reaction solution is to add 1.5-3 mmol of solute per 70 mL of solvent;

The solute is an organic ligand and a metal salt with a molar ratio of 3:1; the organic ligand is preferably 2,5-dihydroxyterephthalic acid; the metal salt is magnesium nitrate or magnesium nitrate and copper nitrate;

The solvent is N,N-dimethylformamide, water, ethanol with a volume ratio of 15:1:1;

Step 62, hydrothermal reaction;

Hang the ninth sample vertically on the polytetrafluoroethylene lining of the hydrothermal kettle, add the reaction solution, put the hydrothermal kettle into an oven for hydrothermal reaction, cool it to 25°C to 40°C and take it out to obtain the tenth sample. Sample;

The hydrothermal reaction temperature is 120℃～125℃, and the reaction time is 4～8h;

Step 63, post-processing;

Soak the tenth sample in DMF for 10-30min to remove unreacted solvent, and then wash with methanol to remove DMF to obtain the eleventh sample;

The eleventh sample was put into an oven with a temperature of 60°C to 80°C and dried for 10 to 40 minutes, and then taken out to obtain a twelfth sample.

2 . The method for preparing a novel coated medical porous zinc material according to claim 1 , wherein the composition of the prepared medical porous zinc coating is Mg-MOF-74. 3 .

3 . The method for preparing a novel coated medical porous zinc material according to claim 1 , wherein the thickness of the prepared medical porous zinc coating is 20-30 microns. 4 .

4 . The method for preparing a novel coated medical porous zinc material according to claim 1 , wherein the prepared medical porous zinc coating has a cell survival rate of 80% under 25% leaching solution culture. 5 .