Nanostructural Organization of Naturally Occurring Composites—Part I: Silica-Collagen-Based Biocomposites

Figure 3

SEM and TEM nanoimagery of the fibrillar organic matrix within partially demineralized spicule. (a) Axial filament is an organization of microfibrils with a diameter of approximately 25–30 nm covered with a silica-containing layer and distributed along the axis of spicule. (b) Nanolocalization of amorphous silica particles (arrows) on the surface of partially demineralized protein fibrils using HRTEM. (c), (d) Collagen fibrils’ orientation within spicule possesses a twisted plywood architecture (arrows).