Electrospun Small Diameter Tubes to Mimic Mechanical Properties of Native Blood Vessels Using Poly (L-lactide-co-ε-caprolactone )and Silk Fibroin: a Preliminary Study

Mismatch in mechanical properties can induce intimal hyperplasia,which is one of the main reasons for the failure of small diameter artificial blood vessels. Electrospun small diameter tubes with tailored mechanical properties were fabricated through blending poly( L-lactide-co-ε-caprolactone)( PLCL) and silk fibroin( SF)with the mass ratios of 30 /70,50 /50,and 70 /30 in this study.Scanning electron microscopy( SEM) and mechanical testing were used to characterize morphological and mechanical properties of the tubes. Results showed that tensile strength of the tubes was higher than most of the native blood vessels,and elongations at break of them were improved greatly by blending PLCL. Compliances of the tubes were all higher than 1% /13. 33 kPa( 1% /100 mmHg).Particularly,tubes with blending mass ratio of 50 /50 showed similar compliance with human native femoral arteries,which provided a promising biomaterial that could be applied on small diameter vascular applications.

Biomimetic three-layered membranes comprising(poly)-e-caprolactone,collagen and mineralized collagen for guided bone regeneration

The distinct structural properties and osteogenic capacity are important aspects to be taken into account when developing guided bone regeneration membranes.Herein,inspired by the structure and function of natural periosteum,we designed and fabricated using electrospinning a fibrous membrane comprising(poly)-e-caprolactone(PCL),collagen-I(Col)and mineralized Col(MC).The three-layer membranes,having PCL as the outer layer,PCL/Col as the middle layer and PCL/Col/MC in different ratios(5/2.5/2.5(PCM-1);3.3/3.3/3.3(PCM-2);4/4/4(PCM-3)(%,w/w/w))as the inner layer,were produced.The physiochemical properties of the different layers were investigated and a good integration between the layers was observed.The three-layeredmembranes showed tensile properties in the range of those of natural periosteum.Moreover,the membranes exhibited excellent water absorption capability without changes of the thickness.In vitro experiments showed that the inner layer of the membranes supported attachment,proliferation,ingrowth and osteogenic differentiation of human bone marrowderived stromal cells.In particular cells cultured on PCM-2 exhibited a significantly higher expression of osteogenesis-related proteins.The three-layered membranes successfully supported new bone formation inside a critical-size cranial defect in rats,with PCM-3 being the most efficient.The membranes developed here are promising candidates for guided bone regeneration applications.