2020 Volume 28 Pages 127-133
The fibrillar structure of Bombyx mori silkworm silk is well known. However, its hierarchical details, such as the average dimensions of nanofibrils and bundles (i.e. fibrils) as well as nanofibril aggregation manner and orientation level, remain incompletely understood. This study investigated the fibrillar structure in B. mori silkworm silk by using small-angle X-ray scattering (SAXS) analysis. SAXS analysis revealed bundles comprising hexagonally packed nanofibrils. To our knowledge, this has never been reported in morphological observations of B. mori silkworm silk or any other native silks. The average diameters of nanofibrils and bundles were approximately 4.7 and 54 nm, respectively. Our results demonstrate the potential of SAXS analysis for investigating the hierarchical fibrillar structures of native silks.