In vitro studies of annulus fibrosus disc cell attachment, differentiation and matrix production on PDLLA/45S5 Bioglass® composite films

The aim of this study was to investigate the potential of using PDLLA/45S5 (PDLLA—poly(d,l-lactide)) Bioglass® composite films for the culture of annulus fibrosus (AF) cells in vitro with a view to a tissue engineering application. PDLLA films incorporated with different percentages (0, 5 and 30 (wt%)) of Bioglass® particles were prepared by solvent casting and characterized by scanning electron microscopy (SEM), water contact angle and white-light interferometry. Bovine AF cell morphology and attachment were analysed using SEM. Cytoskeletal organization was determined by actin labelling with FITC-phalloidin using fluorescence microscopy. The amount of sulphated glycosaminoglycan (sGAG) and collagen produced by AF cells were quantified using the 1,9-dimethylmethylene blue (DMMB) and Sircol™ assays after 4 weeks in culture. Composite films of PDLLA filled with Bioglass® are an appropriate substrate for annulus cells and these films promote the production of an extracellular matrix (ECM) containing abundant sGAGs and collagen. These findings provide a basis for the understanding of the production of ECM molecules by cells cultured on 2D PDLLA/45S5 Bioglass® composite films. The results will provide new insights into the design and development of composites containing Bioglass® and resorbable polymers as scaffolds for intervertebral disc tissue repair.