Structure and Mechanical Properties of Electrospun Tussah Silk Fibroin Nanofibres: Variations in Processing Parameters

Tussah silk fibroin (TSF), a fibrous biopolymer from wild silkworm of the species Antheraea pernyi, was first electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvent at a concentration of 8% (by weight). The effect of processing parameters on the morphology, structure and mechanical properties of electrospun TSF nanofibres was investigated. The electrospun TSF nanofibres presented the band-like morphology using a rectangular aluminium foil as collecting plate and the average diameters ranged from 245 nm to 439 nm according to different spinning parameters. At a spinning distance of 10 cm, the increase of spinning voltage induced the conformation transition of TSF nanofibres from α-helix to β-sheet and random coil; however, at a spinning voltage of 15 kV, the increase of spinning distance induced the conformation transition of TSF nanofibres from random coil to α-helix. Nevertheless, the variation of processing parameters could not change the fact that α-helix and β-sheet conformations co-existed in the fibres and α-helix was the main structure. The mechanical properties of non-woven TSF nanofibrous mats depended more on the assembly of the fibres than on the fibre structure, and the nanofibrous mats with small diameters showed higher mechanical properties. The study showed that the thin and relative uniform rod-like nanofibres with an average diameter of 245 nm could be obtained through a rotary roller as a collecting device. The nanofibrous scaffold prepared in this paper makes a promising candidate scaffold for tissue engineering because of the especial tripeptide sequence of Arg-Gly-Asp (RGD) in TSF.