The preparation method of magnesium and porous beta-calcium phosphate composite material and vacuum suction casting instrument
Technical field
What the present invention relates to is a kind of matrix material, the matrix material of particularly a kind of degradable Mg or Mg alloy and porous bio-ceramic.
Background technology
Bone tissue engineer is the focus in the Tissue Engineering Study, and the research of bone tissue engineering stent material is also being deepened continuously.The more material of research mainly contains degradable polymer and calcium orthophosphate base biological active ceramic material at present.Degradable polymer mainly contains poly(lactic acid) (PLA) and polyglycolic acid (PGA) etc., its stable in properties, and plasticity-and repeatability are good, but strength and stiffness are low, and histocompatibility is poor, and degraded product can cause serious inflammatory reaction.Can absorb calcium phosphate biological ceramic to nontoxic, the no immune response of human body, have excellent biological compatibility, biological activity, bone conduction even bone inductive effect, be beneficial to the growth of osseous tissue behind the implanting to human body, so calcium phosphate biological ceramic is widely used in bone tissue engineer research.Wherein (β-TCP) has favorable biological degradability to beta-calcium phosphate, its calcium phosphorus mass ratio is 1.5, approaching with normal bone tissues, and porous beta-TCP can also provide big specific surface area, help propagation, differentiation and the metabolism of cell, in its implantable bioartificial body, the Ca that degrades, P enters the live body recycle system, to forming area of new bone certain promoter action is arranged.Therefore, generally believe that β-TCP is the inorganic timbering material of a kind of comparatively ideal bone tissue engineer, has tempting application prospect.But because the intensity of porous beta-TCP is lower, toughness is too low, makes it be subjected to certain restriction in the application aspect the bone defect repair.Numerous scholars are in order to improve the mechanical property of porous beta-TCP, and portion's doping metals, ceramic phase, macromolecular material perhaps in porous beta-TCP surface preparation coating, so form various matrix materials within it, but the amplitude of improving is all smaller.Fine and close β-TCP can improve physical strength, but the biological activity performance slowly, is unfavorable for the formation of area of new bone.
Mg has lower Young's modulus, suitable intensity, and good characteristics such as excellent biocompatibility and degradability are a kind of new metallic materials with potential applicability in clinical practice.Mg is the important activator of various enzyme systems in the cell metabolism, can activate many important enzymes.Mg can promote the growth of new bone tissue, can not produce detrimentally affect to human body when Mg degrades with given pace.Therefore Mg is for the growth of regulating cell with keep membrane structure and play an important role.Simultaneously, Mg easily generates the Mg ion and excretes by when injected organism tissue absorption on every side or by body fluid in containing the solution of chlorion (as human body fluid), so Mg can be degraded fully by human body fluid.The Mg alloy is one of the lightest structured material, and its density is at 1.74g/cm
3About, with people's bone density (1.75g/cm
3) quite, and have high specific tenacity and specific rigidity.Yet because Mg Degradation in vivo can change pericellular microenvironment, may cause the toxic action of pair cell, simultaneously, the problem of Mg alloy degradation in vivo excessive velocities also waits to solve.
Summary of the invention
The object of the present invention is to provide and a kind ofly can save preparation time greatly, technology is simple, does not need complex apparatus; The matrix material that makes has good mechanical stability and physical strength, helps the magnesium of reparation of bone and the preparation method of porous beta-calcium phosphate composite material behind the implanting to human body.The present invention also aims to provide a kind of vacuum suction casting instrument that is used to prepare magnesium and porous beta-calcium phosphate composite material.
The object of the present invention is achieved like this:
(1) preparation of beta-calcium phosphate slurry: 60 ℃ of water-baths, set Ca/P=1.48, under the pH=8 agitation condition with the Secondary ammonium phosphate ((NH of 0.3mol/L
4)
2HPO
4) solution splashes into the nitrocalcite (Ca (NO of 0.4mol/L with the speed of 2~3ml/min
3)
24H
2O) in the solution, treat that titration finishes the back at 60 ℃ of insulation 1h, continue to be stirred to naturally cooling behind reheat to 95 ℃~98 ℃ of insulation 2h, leave standstill, natural subsidence is outwelled supernatant liquid and is obtained beta-calcium phosphate solution, adding 2% polyoxyethylene glycol again stirs until there not being bubble to produce, continue to stir and be warmed up to the polyvinyl alcohol of adding 8% after 95 ℃, naturally cool to room temperature after waiting to stir, form the beta-calcium phosphate slurry;
(2) pre-treatment of polyurethane foam: polyurethane foam is cleaned up and ultrasonication 20min after drying with dehydrated alcohol, then polyurethane foam is put into the hydrochloric acid soln soaking and stirring 48h of 2mol/L earlier, washing, drying; Put into 5% sodium hydroxide solution soaking and stirring 48h again, washing, drying;
(3) preparation of porous beta-calcium phosphate precast body: will put into the beta-calcium phosphate slurry through pretreated polyurethane foam, obtain uniform coat through after the repeatedly processing of dipping-extruding, behind 60 ℃ of loft drier inner drying 24h in heat treatment furnace sintering, sintering condition is: the temperature rise rate with 0.8 ℃/min is warmed up to 600 ℃ of insulation 60min with precast body, speed with 5 ℃/min is warmed up to 1150 ℃ then, and the cooling rate with 5 ℃/min is chilled to room temperature behind the insulation 5h;
(4) preparation of Mg or Mg alloy and porous beta-calcium phosphate composite material is carried out on the vacuum suction casting instrument, and detailed process is:
1. the melting of Mg or Mg alloy: with Mg or Mg alloy melting, the insulating covering agent protection, 680 ℃~720 ℃ insulations down, stand-by;
2. vacuum system is bled in advance: open vacuum pump, open the vacuum system extraction valve, vacuum system is evacuated in advance-close vacuum pump and vacuum system extraction valve behind 0.08~0.07MPa;
3. precast body preheating: be installed in the vacuum suction casting instrument after the porous beta-calcium phosphate precast body is preheating to 150 ℃;
4. suction pouring: open vacuum pump, open the vacuum system extraction valve, open precast body air chamber extraction control valve, Mg or Mg alloy liquid are under the effect of vacuum, and the porous beta-calcium phosphate precast body is advanced in filling, and the time relay picks up counting simultaneously;
5. after being incubated 2min, vacuum pump and vacuum system extraction valve and extraction control valve are closed automatically, open the vacuum system pressure release valve simultaneously, after the vacuum breaking, take out, and obtain Mg or Mg alloy and porous beta-calcium phosphate composite material.
The composition that is used to prepare the vacuum suction casting instrument of magnesium and porous beta-calcium phosphate composite material of the present invention comprises that two ends pass through the mould cavity of cover closure up and down, the porous beta-calcium phosphate precast body is installed in the mould cavity, have riser pipe on the lower cover, riser pipe is deep in the container of Mg that fusing is housed or Mg alloy, the outside of container is provided with holding furnace, upper cover plate connects extraction pipe, extraction pipe links to each other with vacuum pump through surge tank, the extraction pipe at surge tank two ends is provided with control valve, also is provided with pressure release valve on the extraction pipe.
Compare with present technology, utilize the method for the invention to prepare matrix material, have that technology is simple, simple operation, do not need complex apparatus, timesaving advantage.The matrix material that makes both can have been alleviated the weakness of porous beta-TCP as the embedded material bad mechanical property, also can solve the problem of magnesium alloy degradation speed and cell compatibility, and can reach the purpose of controlling composite degradation speed and performance by porosity and the pore size of regulating porous beta-TCP.
Existing report adopts the melt infiltration method that magnesium or magnesium alloy are penetrated in the porous tricalcium phosphate base substrate, makes magnesium or magnesium alloy and tricalcium phosphate composite material.Use the melt infiltration method in the preparation composite material, need be incubated infiltrations 1~8 hour, fully penetrate in the hole of porous tricalcium phosphate to guarantee magnesium or magnesium alloy at 700 ℃~800 ℃, more time-consuming like this.The vacuum suction casting technique that the present invention adopts is compared with the melt infiltration method, and porous beta-TCP contacts back 5 minutes with Mg or Mg alloy liquid just can finish preparation process with interior, saved preparation time greatly, and technology is simple, does not need complex apparatus.The gained material structure both can have been alleviated the weakness of porous beta-TCP as the embedded material bad mechanical property, also can solve the problem of Mg or Mg alloy degradation speed and cell compatibility, and can reach the purpose of controlling composite degradation speed and performance by porosity and the pore size of regulating porous beta-TCP.The matrix material of preparation be at first atresia and have good mechanical stability and physical strength, help the bone reparation like this, behind the certain hour, the degraded of Mg or Mg alloy just can form the inner porous beta-TCP structure of perforation mutually, can support bone to grow into like this.Thereby the biodegradable of matrix material and osteoinductive are better coordinated.
Description of drawings
Fig. 1 is the structural representation of vacuum suction casting instrument.
Fig. 2 is the porous beta-TCP precursor structure.
Fig. 3 sucks the microstructure of composite that Mg-1%Ca alloy liquid forms in porous beta-TCP.
Fig. 4 sucks the microstructure of composite that Mg-1%Zn alloy liquid forms in porous beta-TCP.
Embodiment
For example the present invention is done in more detail below and describes:
Embodiment 1:
60 ℃ of water-baths, set Ca/P=1.48, under the pH=8 agitation condition with the Secondary ammonium phosphate ((NH of 0.3mol/L
4)
2HPO
4) solution splashes into the nitrocalcite (Ca (NO of 0.4mol/L with the speed of (2~3) ml/min
3)
24H
2O) in the solution, treat that titration finishes the back at 60 ℃ of insulation 1h, continue to be stirred to naturally cooling behind reheat to 95 ℃~98 ℃ of insulation 2h, leave standstill, natural subsidence is outwelled supernatant liquid and is obtained β-TCP solution, adding 2% polyoxyethylene glycol again stirs until there not being bubble to produce, continue to stir and be warmed up to the polyvinyl alcohol of adding 8% after 95 ℃, naturally cool to room temperature after waiting to stir, form β-TCP slurry.Polyurethane foam is cleaned up and ultrasonication 20min after drying with dehydrated alcohol, then polyurethane foam is put into the hydrochloric acid soln soaking and stirring 48h of 2mol/L earlier, washing, drying; Put into 5% sodium hydroxide solution soaking and stirring 48h again, washing, drying is so that foam has wetting ability preferably.To put into β-TCP slurry through pretreated polyurethane foam, through obtaining uniform coat after the repeatedly processing of dipping-extruding, behind 60 ℃ of loft drier inner drying 24h in heat treatment furnace sintering.Sintering condition is: the temperature rise rate with 0.8 ℃/min is warmed up to 600 ℃ of insulation 60min with precast body, and the speed with 5 ℃/min is warmed up to 1150 ℃ then, and the cooling rate with 5 ℃/min is chilled to room temperature behind the insulation 5h.Fig. 2 is the structure of the porous beta-TCP precast body of preparation.
In conjunction with Fig. 1, the composition that is used to prepare the vacuum suction casting instrument of magnesium and porous beta-calcium phosphate composite material comprises that two ends pass through the mould cavity 6 of cover plate 5 sealings up and down, porous beta-calcium phosphate precast body 7 is installed in the mould cavity, have riser pipe 4 on the lower cover, riser pipe is deep in the container 3 of Mg that fusing is housed or Mg alloy, the outside of container is provided with holding furnace 1, upper cover plate connects extraction pipe, extraction pipe links to each other with vacuum pump through surge tank, the extraction pipe at surge tank two ends is provided with control valve, also be provided with pressure release valve 8 on the extraction pipe, control valve comprises precast body extraction valve 9 and vacuum system extraction valve 10.
Embodiment 2:
Method according to embodiment 1 prepares mesh structural porous structure β-TCP precast body.The Mg-1%Ca alloy is melted in electrical crucible by the atom proportioning, the insulating covering agent protection, 680 ℃~720 ℃ insulations down, stand-by; Vacuum system is bled in advance: open vacuum pump, open the vacuum system extraction valve, vacuum system is evacuated in advance-close vacuum pump and vacuum system extraction valve behind 0.08~0.07MPa; Preheating precast body: the porous beta-TCP precast body is preheating to 150 ℃; Carry out suction pouring: open vacuum pump, open the vacuum system extraction valve, open precast body air chamber extraction control valve, liquid magnesium alloy is under the effect of vacuum, and the porous beta-TCP precast body is advanced in filling, and the time relay picks up counting simultaneously.Behind the insulation 2min, vacuum pump and vacuum system extraction valve and extraction control valve are closed automatically, open the vacuum system pressure release valve simultaneously, after the vacuum breaking, take out sample, obtain Mg or Mg alloy and porous beta-TCP matrix material.Fig. 3 injects the microstructure of composite that Mg-1%Ca alloy liquid forms in porous beta-TCP.As can be seen from the figure, β-TCP combines well with the Mg-1%Ca alloy, and the microstructure of composite densification has also kept β-TCP and Mg connectedness separately simultaneously.
Embodiment 3:
Method according to embodiment 1 prepares mesh structural porous structure β-TCP precast body.The Mg-1%Zn alloy is melted in electrical crucible by the atom proportioning, the insulating covering agent protection, 680 ℃~720 ℃ insulations down, stand-by; Vacuum system is bled in advance: open vacuum pump, open the vacuum system extraction valve, vacuum system is evacuated in advance-close vacuum pump and vacuum system extraction valve behind 0.08~0.07MPa; Preheating precast body: the porous beta-TCP precast body is preheating to 150 ℃; Carry out suction pouring: open vacuum pump, open the vacuum system extraction valve, open precast body air chamber extraction control valve, liquid magnesium alloy is under the effect of vacuum, and the porous beta-TCP precast body is advanced in filling, and the time relay picks up counting simultaneously.Behind the insulation 2min, vacuum pump and vacuum system extraction valve and extraction control valve are closed automatically, open the vacuum system pressure release valve simultaneously, after the vacuum breaking, take out sample, obtain Mg or Mg alloy and porous beta-TCP matrix material.Fig. 4 injects the microstructure of composite that Mg-1%Zn alloy liquid forms in porous beta-TCP.As can be seen from the figure, β-TCP combines well with the Mg-1%Zn alloy, and the microstructure of composite densification has also kept β-TCP and Mg-1%Zn alloy connectedness separately simultaneously.
Can draw advantage of the present invention from above-mentioned experiment is: utilize the method for the invention to prepare composite, having technology simply, does not need complicated equipment, simple operation, timesaving advantage. The composite of preparation be at first atresia and have good mechanical stability and mechanical strength, be conducive to like this bone reparation, implant certain hour after, the magnesium alloy degraded just can form the inner mutually porous beta-TCP structure of perforation, can support like this bone to grow into. The composite of preparation both can have been alleviated porous beta-TCP as the weakness of embedded material bad mechanical property, also can solve the problem of the too fast and cell compatibility of magnesium alloy degradation speed, and porosity that can be by regulating porous beta-TCP and the pore size purpose that reach control composite degradation speed and performance.