Poriferan Chitin as the Scaffold for Nanosilica Deposition under Hydrothermal Synthesis Conditions

Chitin is a structural aminopolysaccharide found in cell walls of fungi and diatoms as well as various skeletal formations of numerous invertebrates including marine sponges (Porifera). The occurrence of silica within chitin-based skeletons of sponges has inspired development of silica-chitin hybrids and composites in vitro with unique physico-chemical properties. We show that the two dimensional alpha-chitin scaffolds isolated from skeletons of the marine demosponge Ianthella basta can be effectively silicified by the combined sol-gel/hydrothermal method with the use of Stober silica. The nanostructured silica-chitin composites obtained under these Extreme Biomimetic conditions (120 degrees C) were characterized by the presence of spherical SiO2 nanoparticles homogeneously distributed over the chitin fibers, which probably follows from the compatibility of Si-OH groups to the hydroxyl groups of chitin. The biocomposites obtained were characterized by various analytical techniques such as Energodispersive X-ray Diffraction (EDS), Scanning Electron Microscopy (SEM), Thermal Analysis (TG/DTA) as well as FT-IR spectroscopy.