Composite poly(l-lactic-acid)/silk fibroin scaffold prepared by electrospinning promotes chondrogenesis for cartilage tissue engineering

Abstract

Nanofibrous materials produced by electrospinning have attracted considerable attention from researchers in regenerative medicine. A combination of nanofibrous scaffold and chondrocytes is considered promising for repair of cartilage defect or damage. In the present study, we fabricated a poly(l-lactic-acid) (PLLA)/silk fibroin (SF) nanofibrous scaffold by electrospinning and evaluated its chondrogenic potential. The PLLA/SF nanofibers were characterized for diameter, surface wettability, swelling ratio, and tensile strength. Throughin vitroexperiments, PLLA/SF scaffold-chondrocyte interactions were investigated relative to the unmodified PLLA scaffold with regard to cellular adhesion, spreading, and proliferation by scanning electron microscopy and confocal laser scanning microscopy, and through analyses of DNA, sulfated glycosaminoglycan, and collagen. In addition, hematoxylin-eosin and Alcian blue-nuclear fast red staining were used to observe growth of chondrocytes, and secretion and distribution of cartilage-specific extracellular matrices in the scaffolds. Expressions of cartilage-related genes (collagen II, aggrecan, sox9, collagen I, and collagen X) were detected by real-time quantitative PCR. The PLLA/SF scaffold had better hydrophilicity, and could support chondrocytes adhesion and spreading more effectively than the unmodified PLLA scaffold. Chondrocytes secreted more cartilage-specific extracellular matrices and maintained their phenotype on the PLLA/SF scaffold. So it is concluded that the PLLA/SF scaffold is more conducive toin vitroformation of cartilage-like new tissues than the unmodified PLLA scaffold, and may be a promising material in cartilage tissue engineering.

Keywords: Electrospinning; cartilage tissue engineering; chondrocytes; nanofiber; poly-(l-lactic-acid); scaffold; silk fibroin.