The ability of many arthropods to spin silk and its many
uses bear
testament to its importance in Nature. Despite over a century of research,
however, the spinning process is still not fully understood. While
it is widely accepted that flow and chain alignment may be involved,
the link to protein gelation remains obscure. Using combinations of
rheology, polarized light imaging, and infrared spectroscopy to probe
different length scales, this work explored flow-induced gelation
of native silk feedstock fromBombyx morilarvae. Protein chain deformation, orientation, and microphase separation
were observed, culminating in the formation of antiparallel β-sheet
structures while the work rate during flow appeared as an important
criterion. Moreover, infrared spectroscopy provided direct observations
suggesting a loss of protein hydration during flow-induced gelation
of fibroin in native silk feedstock, which is consistent with recently
reported hypotheses.