Preparation And Experimental Study On The Biological Activity Of PLGA/CPC Scaffold

As the interdisciplinary subject in the research field,tissue engineering hasinvolved in both the material engineering and the molecular biology;meanwhile,it alsocould be used to restore,maintain or improve the function of tissue and whole organ asa biological substitutes.The four primary tools to regenerate tissues include cells,scaffolds, growth factors and environment. One of the major strategies in tissueengineering is to employ a suitable scaffold. Currently, the material constitutes thescaffold synthetic polymers such as poly (caprolactone), poly (lactic acid-co-glycolic acid), poly (ethylene glycol), poly (vinyl alcohol), and natural polymers suchas alginic acid,collagen, gelatin, and chitosan. As a widely used material,poly(lactide-co-glycolide,PLGA) is a polymeric ester of the lactic and glycolic acids.Thegood mechanical property and biocompatibility of the PLGA scaffold suggest apromising advantage for tissue engineering. Calcium phosphate cements(CPC) can bemolded randomly according to the shape of the bone defective.Its final degradationmaterial is hydroxyapatite (HA) that is similar to the inorganic principle of human bonetissue.Consequently, CPC exhibits a high level of biocompatibility and osteoconductivity,and it has been also widely used as bone substitutes in bone tissue engineering.In thisstudy,PLGA and CPC were adopted as the matrix materials in order to obtain thescaffold materials with good biocompatibility and biodegradability which can beapplied in the area of biomedical engineering and bone tissue engineering.In this experiment,we divided the experiment into three groups by adjusting thequality ratio of the PLGA and CPC.The quality ratio was8:2、7:3and6:4,and themethod of preparing the composite is called solvent casting-particulate leaching/phase separation technique. Firstly,we prepared PLGA/CPC scaffolds with a mixtureof sugar particulate (d=200-300μm), using it as a porogen additive. Secondly，the three groups of PLGA/CPC scaffolds were examined on their pore size，porosity anddegradation rate, and on the attachment and proliferation of BMSCs. Then wesystematically evaluated its bioactivity and chose the best matching proportion ofPLGA/CPC scaffolds.The results demonstrated that the three groups of scaffolds possessed uniformpore distribution,good interconnection and controllable pore size.The porosity of7:3PLGA/CPC scaffold was91.18%, slightly higher than the other two groups. In theinitial stage of degradation, the mass loss of scaffold was slow,and there was nosignificant difference among the three scaffolds.After14days,the degradation ratewas increasing,and the mass loss ratio was growing too.The difference among thethree groups was statistically significant(P<0.05).Cell compatibility studies showedthat, compared with the control group,BMSCs in three kinds of material all grewwell.In the day of1,3,5,7,only the ODs of7:3scaffold were always higher thancontrol group and the7:3material had no cytotoxicity.The above conclusions showedthat the group of7:3scaffold displayed larger pores and higher porosity,and couldimprove the level of cells proliferation slightly.The innovation of this study was the first preparation of the newPLGA/CPC scaffold material with appropriate proportion.The biodegradability andbiocompatibility of PLGA/CPC scaffold material were evaluated by ESEM, porosity,mass loss ratio and CCK-8assay, which provided the oretical basis and experimentalbasis for further clinical application.