Micro- and nano-structural characterization of six marine sponges of the class Demospongiae.

The sponges produce their skeletal elements and silicateins are the key enzymes in this process. The mechanism underlying the formation of their silica skeleton and its structural properties are of exceptional interest for applications in technology. Micro- and nano-scale structural analysis of the six marine sponges belonging to Demospongiae [Callyspongia (Cladochalia) plicifera (Lamarck, 1814), Cervicornia cuspidifera (Lamarck, 1815), Cinachyrela sp., Niphates erecta (Duchassaing and Michelotti, 1864), Xestospongia muta (Schmidt, 1870) and Amphimedon compressa (Duchassaing and Michelotti, 1864)] were carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Small-Angle X-ray Scattering (SAXS) techniques. The nano-structural characterizations give some informative evidence about the manner in which silica/silicatein in spicule skeletons is produced by the sponges. The sponge species were successfully discriminated using cluster analysis (HCA) based on FTIR spectra. This study demonstrates and detection of structural differences among sponges and their spicules using combined techniques.