Characterization of the pore labyrinth geometry of sea sponges imaged by micro-CT

The internal pore labyrinths of sea sponges were characterized via the analysis of 3D micro-CT images. Methods were developed to isolate and segment the pores and to extract the pore 'skeleton', which facilitated the measurement of local pore dimensions and connectivity. These methods were also used to characterize the bulk pore properties such as porosity and structural surface-to-volume ratios, as well as individual pathway analysis in terms of lengths, diameters, and tortuosity. Also, the role that ciliated cells (lining the pores) might play in the transport of fluids throughout the pore labyrinth was explored. It was deduced that cilia may play a larger role in the transport of fluids through smaller diameter pathways and the highly interconnected pathways of the sponge results in a robust network that can maintain nutrient delivery/waste removal in the case of obstruction of some of the pore pathways. Finally, it is discussed how the information gained from this study might be applied to design synthetic porous tissue scaffolds.