Microstructures of Bombyx mori Silk and Spider Silk Revealed by Atomic Force Microscopy

The microstructures of Bombyx mori fibroin and dragline, egg-case silk fibers of Araneus Ventricosus spider were studied by atomic force microscopy (AFM). The results indicated that there were clear stripes formed by the flow elongation of liquid fibroin during spinning process in the surfaces of fibroin and spider egg-case silk. The natural dragline silk secreted by a spider at low rate had finer structure in its skin surface than fibroin, and the dragline silk secreted by a dropping spider at high rate had similar microstructures with that of fibroin. There were a great number of circular nanofibrils within these samples. The diameters of three kinds of spider silk were similar and smaller than that of Bombyx mori fibroin.