MASTER THESIS Biomimetic potential of sponge ... - IAP/TU Wien

Summary
Investigation of siliceous sponges and their endoskeleton allows inferring multiple useful
concepts for biomimetic innovations. A wealth of research has been published regarding the
unique synthesis mechanism as well as structural, mechanical and optical properties of this
astounding biomaterial.
Hierarchical architecture and nanostructuring are the two main factors yielding a strong,
tough and yet flexible SiO 2 -based composite. This has been stressed by contrasting
engineered structures and the highly hierarchical skeleton of the glass sponge Venus’ Flower
Basket.
The low temperature synthesis of spicules can be subdivided into three basic steps, all of
which occur within or in close association with specialized cells. Depending on the class of
sponges and the type of spicule within a sponge, spicules can become solid in the last step
(most demosponges) or retain a distinct, layered structure (most hexactinellids). To
appreciate the peculiarities of spiculogenesis, the pathway of synthesis has been contrasted
to other mineralization processes.
It became apparent that the enzymatic control of this process is a useful role-model for
sustainable low-temperature fabrication methods in nanotechnology, bone replacement
materials and for other metal-oxide materials. In a short digression, the synthesis of artificial
nacre is highlighted. This calcareous biomaterial has been copied in even more convincing
ways than spicules and provides hints for successful biomimetic fabrication of hard
materials. Especially the optical properties of this transparent material raised the interest of
researchers in communication engineering and laser physics. For the latter field nonlinearoptical
properties of sponge spicules including Bragg reflection and a variable fluorescence
decay time are interesting. For communication technologies resemblance between spicules
and waveguides has triggered research revealing that sponge spicules can conduct light in
single- and multimode regimes. The effective guidance of light through spicules, that has
been shown to serve a biological purpose in some sponges, suggested an application in
daylighting systems.
Buildings have adopted geometries that became only possible thanks to the availability
of artificial light in the last century. However, currently we are re-discovering the importance
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