Influence of Hydration on the Micromechanical Properties of Silica Spicules from the Venus Flower Basket (Euplectella Aspergillum)

The spicules of the deep-sea sponge Euplectella aspergillum show exceptional mechanical properties due to their unique layered structure. In the present study, a systematic study utilizing in situ nanoindentation was conducted to understand the influence of water on the micromechanical properties of these spicules. The properties of the spicules were investigated in three conditions-dry state, after 24 h of exposure, and after 1 week of exposure with water. To isolate the effect of the architecture of the spicule, properties of the central core and layered regions of the spicule were probed separately. The results of nanoindentation revealed that the layered regions were significantly softer and more compliant than the central core of the spicule. The properties of the central core remained unchanged when exposed to water. On the other hand, layered regions showed a decrease in their stiffness and hardness. These effects were attributed to the hydrated nature of silica and plasticization of the organic interlayers, respectively. The present results provide insight into the role of the architecture of the spicule and its organic-inorganic constituents in determining its mechanical behavior in water environment.

Automated summary

The properties of the deep-sea sponge Euplectella aspergillum's spicules were investigated using in situ nanoindentation in different water conditions. The layered regions of the spicules were found to be softer and more compliant than the central core. Exposure to water resulted in a decrease in stiffness and hardness of the layered regions, indicating the influence of hydration and plasticization on the mechanical behavior. These findings provide insight into the role of spicule architecture and its constituents in determining mechanical properties in a water environment.