Three-dimensional culture of annulus fibrosus cells within PDLLA/Bioglass® composite foam scaffolds: Assessment of cell attachment, proliferation and extracellular matrix production

The objective of the present study was to assess cell attachment, proliferation and extracellular matrix (ECM) production by bovine annulus fibrosus (BAF) cells cultured in vitro in PDLLA/Bioglass® composite foams. PDLLA foams incorporated with different percentages (0, 5 and 30 wt%) of Bioglass® particles were prepared by thermally induced phase separation (TIPS) process and characterized by scanning electron microscopy (SEM). BAF cell morphology and attachment within the PDLLA/Bioglass® foams were analysed using SEM. An assessment of cell proliferation was conducted using the WST-1 assay. The amount of sulphated glycosaminoglycans (sGAG) were quantified using the 1,9-dimethylmethylene blue (DMMB) assay after 4 weeks in culture. Furthermore, the amount of collagen synthesis was determined using a hydroxyproline assay, and the presence of collagen types I and II was investigated using Western blotting. Our results reveal that PDLLA/Bioglass® foam scaffolds can provide an appropriate microenvironment for BAF cell culture which enhances cell proliferation and promotes the production of sGAG, collagen type I and collagen type II. These findings provide preliminary evidence for the use of PDLLA/Bioglass® composite scaffolds as cell-carrier materials for future treatments of intervertebral discs with damaged AF regions.