Co-electrospun nanofiber fabrics of poly(L-lactide-co-epsilon-caprolactone) with type I collagen or heparin

Functionally designed elastomeric nanofiber fabrics made of the equimolar copolyester, poly(L-lactide-co-epsilon-caprolactone) (PLCL), with type I collagen or the tri-n-butylamine salt of heparin (heparin-TBA) were co-electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent. The co-electrospun fabrics (mixing ratio: 0, 5, 10, 30, 50, 70, and 100 wt % of collagen to PLCL) consisted of nanoscale fibers with a mean diameter ranging from approximately 120 to 520 nm. An increase in collagen content in the solution resulted in a decrease in the mean diameter of fibers. Transmission electron microscopy (TEM) showed that collagen in a co-electrospun fiber was phase-separated to form a dispersed phase, which was localized in the interior and peripheral region in the continuous matrix phase of fibers. The tensile strength was decreased with increasing collagen content. Human umbilical vein endothelial cells (HUVECs) were highly elongated and well spread on the fibrous surfaces of fabrics made of PLCL with 5 wt % or 10 wt % collagen. Heparin-TBA (mixing ratio: 1, 5, and 10 wt % to PLCL), soluble in HFIP, was co-electrospun with PLCL to form a fabric. TEM observation showed that heparin-TBA formed as a dispersed phase in a PLCL nanofiber. The releasing rate, released amount, and surface content of heparin-TBA were increased with increasing heparin-TBA content in co-electrospun fabrics. The potential biomedical application of co-electrospun PLCL with type I collagen or heparin-TBA was discussed.