Mechanical and cellular characterization of electrospun poly(l-lactic acid)/gelatin yarns with potential as angiogenesis scaffolds

Abstract

Electrospun PLLA/gelatin yarns with different compositions were fabricated as tissue engineering scaffolds. The yarns were characterized by scanning electron microscopy (SEM) and tensile mechanical testing. Cell interaction with yarns was investigated by measurements of cell viability, proliferation, morphology, phenotype, and angiogenic activity (measurement of nitric oxide) using human umbilical vein endothelial cells (HUVECs). The SEM images of yarns showed a uniform structure with axial alignment of the fibers in the yarn surface. The mechanical properties of the yarns changed with the amount of PLLA, indicating the yarn of 40% PLLA and 60% gelatin had the highest stress-at-break (2.47 MPa). Also, there was an increase in the toughness with increasing in the amount of PLLA content in the PLLA/gelatin composition. After 7 days, HUVECs exhibited the best viability and proliferation responses on a yarn of 70% PLLA and 30% gelatin, having 223.56% increase in viability and 306.17% increase in proliferation compared with those of HUVECs alone without any yarns (the control group). Measurement of nitric oxide after 5 days suggested potential applications of yarns in angiogenesis, such as cardiovascular disease and wound healing, with a yarn of 70% PLLA and 30% gelatin having the highest ratio of released nitric oxide (156.20% of the control group). Having a uniaxial structure, the PLLA/gelatin yarns introduced in this study can provide more effective implantation in tissue engineering applications facing geometric and accessibility constraints, such as fibrous tissue regeneration.