Silk has fascinated humans since ancient times; silk fibres have been used in textiles for more than 5,000 years and for many centuries as a suturing material (Lubec, Holbaubek et al. 1993, Omenetto and Kaplan 2010). The remarkable strength and toughness of silk stems from its evolution as a structural engineering material in nature (Vollrath and Porter 2009, Buehler 2013). Silk is a sustainable and ecologically benign biopolymer that can be manufactured using green processes (Vollrath and Porter 2009). Over the past 25 years, we have seen a tremendous development of both bottom-up and top-down approaches for the generation of silk biopolymers