5Hermann Ehrlich et al.
Figure 5: Proposed model of nanostructural organization of the naturally occurring silica-chitin composite unit (a) isolated from spicules of R. fibulata. Silica nanoparticles tightly surround chitinous nanofibrils (b). Schematic view (c) shows a possible nanodistribution of silica on the surface of chitinous nanofibril. Image (d) represents the hypothetic scheme of interaction between silica and poly-N-acetyl glucosaminefragment of the chitin nanofibril and formation of the corresponding hydrogen bonds.
