TEM and X-ray photoelectron spectroscopic studies of wool fibers after cuticle removal

A method is described for cleanly separating the cortex and cuticle of wool fibers using water or an aqueous buffered solution as the immersion medium. Nearly complete removal of cuticle cells can be achieved in 2–3 hours when snippets of wool are vortex-mixed with a suspension containing both glass fiber snippets and glass beads. Examination of treated fibers (transverse sections) by transmission electron microscopy indicates removal of cuticle cell layers (endo- and exocuticle), together with associated membrane intracellular bands (i-layers). The surface elemental composition of the fiber (determined using x-ray photoelectron spectroscopy) changes appreciably with cuticle removal. The sulfur content of the intracellular cortical proteins at the exposed surface is estimated to be 2%, compared to 9% for the epicuticle proteins at the surface of untreated wool.