Silica is an extremely important inorganic material1 and is
extensively used for a wide range of commercial applications
such as resins, molecular sieves, catalyst supports, fillers in
polymers, as well as in biomedical applications.2 In general,
porous inorganic microstructures are of interest as low density
and thermally stable particles, and also as mechanically resistant
encapsulation structures. The chemical syntheses of silica-based
materials are not only relatively expensive and eco-hazardous,
but also often require extremes of temperature, pressure, and
pH. In contrast, biosilicification by living organisms such as
cyanobacteria, diatoms, sponges, and plants proceeds under mild
physiological conditions and results in a diversity of complex
and hierarchical biogenic silica nanostructural frameworks