The Composition Of PPC/PBS And PRF With Freeze-drying Fundamental And Application Research

Objective and background：Most of the patients have different degrees of bone defective inclinical. In recent years, how to promote osteogenesis has been a hotproblem in implant area. Because of the great number of growth factorsincluding in the platelet-rich fibrin, the membrane has a good applicationprospect. There are a lot of clinical reports point that the platelet-richfibrin membrane has been applied to various types of bone defective. Butthe problems still exist, for example, the growth factors are easy to lost,and hard to save, the effective time is short, and the speed of sustainedrelease is too fast. These problems are needed to be resolved.Researches show that, transforming growth factor-β (TGF-β)、vascular endothelial growth factor（VEGF）、insulin-like growth factor-Ⅰ（IGF-Ⅰ）、 platelet-derived growth factor (PDGF） can promoteosteogenesis. The Choukroun’s PRF is rich in the growth factors, and thefactors have been mentioned including it.Researches show that, there is a porous structure in the freeze-dryingdrugs, and it can be stored stably for a long time. It is also easy to berestored activity in the water environment. Therefore, freeze-dryingtechnology is widely spread in the preparation of solid protein, instant oral drugs, and drug embedding liposome, etc. From the database of thestate drug administration we can know that, the drug injection withrecombinant human granulocyte macrophage colony stimulating factor,human recombinant interferon α1b for injection, external use freeze-driedrecombinant human epidermal growth factor, lyophilized mouseepidermal growth factor, recombinant interleukin-2for injection,injection with recombinant human growth hormone, injection withrecombinant streptokinase, injected with human recombinant interferonα2b, freeze-dried blood clotting factor VIII, group A streptococcus,phloroglucinol injection oral lyophilized pieces, lyophilized humanfibrinogen, these freeze-drying drugs are obtained the permission in themarket. February in2000,76kinds of biotech drugs have been approvedby the FDA in USA.In this experiment, we are aimed to research the activity effectiveafter freeze-drying for the PRF, in order to provide experiment basis forthe save, controlled-release, and multiple utilization of the PRF.Methods:Take the New Zealand big-eared white rabbit which are3.0kg above,take blood from the ears marginal vein, make the Choukroun’s PRF,freeze-dried, measurement the net weight, put them in saline solution andsimulated body fluid respectively. Measurement the net weight afteralcohol gradient dehydration in1d、3d、7d、14d、21d and30d. Calculate weightlessness rate. Control group: Choukroun’s PRF, experimentalgroup: the Choukroun’s PRF after lyophilization, composite membraneafter freeze-drying. Each group has three samples.Prepare the Choukroun ’s PRF for human blood, freeze-drying, examthe the Choukroun’s PRF after lyophilization and composite membraneafter freeze-drying by scanning electron microscope. Control group:Choukroun’s PRF, experimental group: the Choukroun’s PRF afterlyophilization, composite membrane after freeze-drying. Each group hasthree samples. Exam the MTT value and the ELISA value oftheexperimental group and control group in different times.Results:1. The degradation performance test:1) Freeze-dried PRF and fresh PRF have a fast released within24h,freeze-dried PRF is a little faster than fresh PRF;2) Freeze-dried PRF and fresh PRF in rapid degradation of50%within24h, the degradation became slow steady state after24h, thedegradation of composite freeze-drying membrane is minimum;3) No matter the fresh PRF, the pure freeze-dried PRF, or thecomposite membrane after lyophilization, the degradation speed in theSBF is slower than in the NaCl;2. Scanning electron microscopy (sem) results:1) SEM shows that the Choukroun’s PRF can enter into the pore of PPC/PBS and closely combined, there is a loose pore structure in thefreeze-dried PRF;3. MTT method to detect the effective for MG-63`S multiplicationcapacity1) The MTT results showed that the promoted cell proliferation ofcomposite film is stronger than the freeze-dried PRF, slightly smaller thanfresh Choukroun’s PRF;2) The composite membrane of the cell proliferation rate showed atrend of uniform in the seven days.4. ELISA method to detect freeze-dried affect growth factor release rate1) The growth factors of freeze-dried groups release faster than freshChoukroun’s PRF;2) The lyophilization has some slow-release effective.Conclusion:1. The growth factors of freeze-dried PRF and compositemembrane after freeze-drying are activity, and can promote theproliferation of MG-63;2. The degradation speed and release rate of freeze-dried PRF isthe fastest, but the composite membrane after freeze-drying has theslow-release effect at some degree.