In Vitro Experimental Study Of Three Types Of Scaffolds Used In Periodontal Tissue Engineering

ObjectivesTo study the microstructure, mechanical properties, in vitro degradation and cellcompatibility of three types of scaffold materials: pure chitosan, chitosan-silkfibroin complex and chitosan-silk fibroin-tricalcium phosphate complex as well as toexplore the optimization methods of biological materials as periodontal tissueengineering scaffolds.Then provided the further experimental evidence toperiodontal tissue engineering’s scaffold materials and further animal testing.MethodsSecondary freeze-drying method to prepare three kinds of stents made frompure chitosan, chitosan-silk fibroin complex and chitosan-silk fibroin-tricalciumphosphate complex, study of the microstructure, mechanical properties, in vitrodegradability of the three stents; meanwhile, isolate, culture and induce the bonemarrow stromal cells co-culture them with three scaffolds. Evaluate the cellcompatibility of three kinds of scaffolds on the basis of the cytotoxicity of the stent,direct contact with experiment, the rate of cell adhesion and cell proliferation activity.Results1.test results of the microstructure, mechanical properties, in vitro degradation ofthree kinds of stents.Compared to pure chitosan and chitosan-silk fibroin complex scaffolds,chitosan-silk fibroin-tricalcium phosphate complex scaffolds had a generally stableshape with the maximum aperture value and porosity rate of frozen sectionsmeasured under the light microscope, which were0.30±0.10μm、81.68±8.71% respectively; such kind of scaffolds also had the maximum compression strength,which was1.44±0.96Mpa.As for vitro degradation rate, the three kinds of scaffolds were close to each otherin the fist two weeks. However, in the fourth week chitosan scaffolds and chitosan-faster fibroin protein complex scaffolds degraded faster, at the rate of67.05±1.70%and71.65±2.48%respectively whereas chitosan-silk fibroin-tricalcium phosphatecomplex scaffolds degraded at a relatively slow rate of58.06±1.99%, which bettermatched the rate of tissue regeneration.2. test results of the cytotoxicity of the scaffoldsMTT assay chitosan-silk fibroin-tricalcium phosphate complex bracket at eachtime point concentration extracts more than75%, the relative growth rates of theL-929(mouse skin fibroblasts). Toxicity was graded as grade0or grade1, no celltoxicity, good biocompatibility, can be used as implant materials.3. test results of cell compatibilityUnder scanning electron microscope, cells grew well, full in shape, andprojecting a plurality of protrusions adhered to the surface of the material, scatteredor concentrated within the porosity of the scaffolds Compared to pure chitosanscaffolds and chitosan-silk fibroin complex scaffolds, chitosan-silk fibroin-tricalcium phosphate complex scaffolds had a higher rate of cell adhesion and ahigher cell proliferation activity and thus promote the adhesion and proliferation ofbone marrow stromal cells.ConclusionThe use of different materials to build composite scaffolds is an optimization method ofusing biological materials as periodontal tissue engineering scaffolds. The chitosan-silk fibroin-tricalcium phosphate composite scaffold shows obvious advantages in microstructure,mechanical properties, in vitro degradability and cell compatibility by in vitro experiment, whichmakes it potentially valuable to be used as periodontal tissue engineering scaffolds.