The Study Of Biodegradable Composite Film Of RhBMP-2

Objective:To enhance BMP effectively induce osteogenesis,the rhBMP-2 chitosan microspheres were formed by emulsion cross-linking with chitosan. The rhBMP-2 chitosan microspheres were compounded biodegradable gelatin sponge and constructed biodegradable controlled release membranes of bone morphogenetic protein.Methods:1.NaOH/rhBMP-2/chitosan microspheres were prepared by crosslinking emulsion,choosing H2SO4 as emulsifiers,Observing the morphological characteristics,cell compatibility and sustained release of the chitosan microspheres.2.The composite films were composed of rhBMP-2,chitosan microspheres and gelatin sponge.The control studies among the composite film,rhBMP-2/chitosan microspheres and gelatin sponge were finished by observing and analyzing the release situation of the composite membranes in vitro release experiment.3.According the animal experiments bone defect model,observing the biodegradable bone morphogenetic protein complex film to induce sustained release capabilities and osteogenesis.The degradable protein complex films were implanted into bone defect area using bone defect model of New Zealand white rabbits.Observing the rhBMP-2/chitosan microspheres/gelatin sponge induce bone forming situation by radiological examination,histology and immunohistochemistry detection,detecting the bone mass of samples bone defect area,calcium and alkaline phosphatase at certain time points.All the data were processed by SPSS 19.0 statistical software package,The data between groups were described by mean±standard deviation (x±s),and compared by analysis of variance.Set the a=0.05 as detection level and p<0.05 considered statistically difference.Result:NaOH-chitosan microspheres were successfully prepared by emulsifying crosslinked load rhBMP-2,used chitosan as raw material. NaOH-chitosan microspheres have regular shape,uniform dispersion and being good at into the ball.Comparand with simple absorbable gelatin sponge scaffold,the chitosan microsphere composite film have less burst releasing of early stage,slow releasing in medium and late stages.The cytotoxicity of chitosan microspheres were detected as grade one,and good histology compatibility by method MTT.With rabbit radial bone defect model at the construction,by general observation,imaging eaaming,testing of bone mass,bone density,calcium content and alkaline phosphatase activity analysis,the experimental results show that:the bone metabolic activity of bone defects,bone defect healing effect of the experimental group is significantly better than the control group.Conclusion:1.The chitosan microspheres were prepared by emulsion cross-linking method choosing H2SO4 as emulsifiers,which presented good biocompatibility and high protein adsorption.This method process is simple.The chitosan microspheres presented stability.2.Using chitosan as raw material,rhBMP-2 complex films were prepared with gelatin sponge.According to vitro release experiment,observation and analysis the implanted rabbit bone defect model,rhBMP-2 NaOH-contained chitosan microspheres and gelatin sponge positively charged by stabilizing electrostatic interactions can effectively improve the function of controlled release composite film.It is suggested that the composite material as a scaffold has better induction osteogenesis than a simple gelatin sponge.