Abstract 3

Evaluation of natural marine sponges as potential bioscaffolds for the attachment, proliferation and differentiation of osteoblastic cells

Kellie L. Solomon^1,2, Craig Willers¹, Michael A. Borowitzka², Jiake Xu, Ming H. Zheng1 and Nathan J Pavlos1.

¹Unit of Orthopaedics, School of Surgery and Pathology, University of Western Australia, Nedlands, Perth. Western Australia.

²Biological Science Division, School of Biological Sciences and Biotechnology, Murdoch University, Perth, Western Australia.

The use of bioscaffolds and cell constructs to support cell growth and tissue regeneration is becoming an ever increasing practice in orthopaedic surgery. However, donor availability and the number of scaffolds suitable for the treatment of osseous injury remains limited. In search of potential bioscaffolds for cell-based bone tissue regeneration we have evaluated the use of natural marine sponges to support the growth and differentiation of osteoblastic cells in vitro. For this purpose, 5 unidentified sponge species of genus Hippospongia (n=1), Callyspongia (n=3), and family Chalinidae (n=1) were selected as candidate scaffolds based on i) hydration potential, ii) fiber matrix architecture, and iii) collagenous composition of spongin fibers. Primary osteoblastic cells seeded onto devitalised sponge matrices were assessed for their ability to attach to, invade, and proliferate in each sponge type using a combination of light, confocal and scanning electron microscopy. In short term cultures (7-days), cellular attachment was observed on all 5 species with cells often aligning along the longitudinal axis of sponge fibers. At 14-days, increased cellular invasion and proliferation was apparent, with osteoblastic cells displaying signs of early-phase matrix deposition. By 21-days culture, osteoblastic cells were found to completely bridge interconnecting spongin-fiber pores, with total encapsulation of sponge skeletons observed in some species. Importantly, the osteoblastic phenotype of these cells was confirmed by staining for alkaline phosphatase. Together with preliminary biocompatibility studies our data indicate that natural marine sponge skeletons may offer a potential new source of bioscaffold for the repair of bone injury.

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