Diatoms are unicellular algae that belonging to the class Bacillariophyceae. They inhabit nearly all aquatic
environments from marine to freshwater and moist habitats. These organisms create highly ornamented external
siliceous shells of multi-layer structure with multi-scale porosity. The main objective of this study is to explore the
utilization of diatom-derived porous structures in nanotechnology. The present study is based on five dominant species
identified and described from 59 samples collected from different habitats in Egypt. The studied taxa included
Actinocyclus cf. octonarius Ehrenberg, Aulacoseira granulata (Ehrenberg) Simonsen, Cyclotella meneghiniana
Kützing and Pleurosira laevis (Ehrenberg) Compére. Nanoporous structures of the considered taxa have been well
investigated through SEM analysis. The sizes of nanoporous silica were found in the range of 5 to 500 nm. The
obtained results showed the potential of diatoms as a source of natural silica micro-particles with micro- to nano-porous
structures with prospective applications as supports for catalysis, selective adsorption, sensors, membranes, and other
novel nanotechnological applications.