a FAST-1 compression meter (CSIRO, Australia), under a load of
2 gfcm
−2
.
The porosity and the specific surface area of the keratin nanofi-brous membranes were calculated on a square sample of 4 cm
2
as
suggested by Ki et al. [14] and described in previous works [16,17].
Practically, the specific surface area (S) of the membranes is
expressed by the ratio between the total surface area A (m
2
) and
the mass of nanofibrous membranes m (g), as shown in Eq