Vascular tissue engineering scaffolds from elastomeric biodegradable poly(L-lactide-co-&-caprolactone)(PLCL) via melt spinning and electrospinning

by 1982- Chung, Sang Won

CHUNG, SANG WON. Vascular Tissue Engineering Scaffolds from Elastomeric Biodegradable Poly(L-lactide-co-?-caprolactone) (PLCL) via Melt Spinning and Electrospinning. (Under the direction of Dr. Martin W. King.) Three dimensional scaffolds play an important role in tissue engineering as a matrix that provides the cells with a tissue specific environment and architecture. For cardiovascular applications in particular, the development of elastic scaffolds that can maintain their mechanical integrity while being exposed to cyclic mechanical strains is a necessary criterion. The main objective of this study was to demonstrate the feasibility of fabricating vascular tissue engineering scaffolds via two different approaches, namely; melt spinning and electrospinning. Small diameter tubes were fabricated from two different molecular weights of elastomeric biodegradable poly(L-lactide-co-?-caprolactone) (PLCL) copolymers. Firstly, 6mm length tubular constructs with the inner diameter of 3/16 inch were produced via melt spinning, and secondly, nanofibrous scaffolds with the inner diameters of 1/8 inch and 3/16 inch were produced via electrospinning. The melt spun tubes produced from the higher molecular weight copolymer contained fibers measuring 253±36?m in diameter, had a porosity of 76.2%, transverse tensile strength of 26.1±1.3MPa, transverse tensile peak strain of 578±17%, and initial transverse tensile elastic modulus of 23.5±0.9MPa. In comparison the electrospun tubes contained nanofibers measuring 540±190nm in diameter, had a porosity of 83.6%, average pore size of 2.08±1.61?m2. The initial modulus of these 3/16 inch diameter nanofibrous scaffolds (24.6±1.9MPa) was similar to that of the melt spun tubes. However, the peak transverse tensile strength was lower at 17.8±2.0MPa and the peak strain was only 142%. Overall, the mechanical properties of the produced tubes exceeded the transverse tensile values of natural arteries of similar caliber. This is the first report that PLCL copolymers can be melt spun into elastomeric fibers. In addition to spinning the polymer separately into melt spun and electrospun constructs, the novel approach in this study has been to successfully demonstrate that these two techniques can be combined to produce two layered tubular scaffolds containing both melt spun fibers (10-200µm in diameter) and electrospun nanofibers (400nm-2µm in diameter).