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 speciesAntheraea 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 processingparameters on the morphology, structure and mechanical properties of electrospunTSF nanofibres was investigated. The electrospun TSF nanofibres presented theband-like morphology using a rectangular aluminium foil as collecting plate and theaverage diameters ranged from 245 nm to 439 nm according to different spinningparameters. At a spinning distance of 10 cm, the increase of spinning voltage inducedthe 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 theconformation transition of TSF nanofibres from random coil to α-helix. Nevertheless,the variation of processing parameters could not change the fact that α-helix andβ-sheet conformations co-existed in the fibres and α-helix was the main structure. Themechanical properties of non-woven TSF nanofibrous mats depended more on theassembly of the fibres than on the fibre structure, and the nanofibrous mats with smalldiameters showed higher mechanical properties. The study showed that the thin andrelative uniform rod-like nanofibres with an average diameter of 245 nm could beobtained through a rotary roller as a collecting device. The nanofibrous scaffoldprepared in this paper makes a promising candidate scaffold for tissue engineeringbecause of the especial tripeptide sequence of Arg-Gly-Asp (RGD) in TSF.