The objective of this study was to assess cell viability, attachment, morphology, proliferation, and collagen and sulphated glycosaminoglycan
(s-GAG) production by human annulus fibrosus (HAF) cells cultured in vitro in poly(D,L-lactide) (PDLLA)/Bioglass composite
foams. PDLLA foams with different percentages (0, 5 and 30 wt.%) of Bioglass particles were prepared by thermally induced phase
separation (TIPS) and characterized by scanning electron microscopy (SEM). HAF cell viability in the PDLLA/Bioglass foam was analysed
using Live/Dead staining. HAF cell attachment was observed using SEM. An assessment of cell proliferation was conducted using
the WST-1 assay. The level of s-GAG and collagen produced by HAF cells was quantified using the 1,9-dimethylmethylene blue
(DMMB) assay and SircolTM assay after 4 weeks of culture. The presence of collagen types I and II within the PDLLA/Bioglass composite
foams was analysed using immunohistochemistry. Live/dead staining showed that many viable HAF cells were present on the top
surface of the foams as well as penetrating into the internal pore structure, suggesting that the PDLLA/Bioglass composite materials are
non-toxic and that the presence of Bioglass particles within PDLLA scaffolds does not inhibit HAF cell growth. The SEM observations
revealed that more clusters of HAF cells were attached to the pore walls of both the PDLLA/5BG foam and the PDLLA/30BG foam
when compared with the PDLLA/0BG foam. WST-1 assay performed over a period of 4 weeks showed an increased tendency of HAF
cells to proliferate within both the PDLLA/5BG foam and the PDLLA/30BG foam when compared with both the tissue culture plastic
control and the PDLLA/0BG foam, indicating the presence of Bioglass in the foam has a positive effect on HAF cell proliferation.
SircolTM and DMMB assays showed that HAF cells cultured within the PDLLA/30BG foam had a greater ability to deposit collagen
and proteoglycan when compared with the control and the PDLLA/0BG foam after 4 weeks in culture, suggesting that the increase
of Bioglass content may induce microenvironmental changes which promote the production of extracellular matrix containing abundant
collagen and s-GAG. The immunohistochemical analysis of collagen production demonstrated that collagen produced in all cultures
was predominantly of type I. These findings provide preliminary evidence for the use of PDLLA/Bioglass composite as cellcarrier
materials for future treatments of the intervertebral disc with damaged AF region.
2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.