Silk Fibroin Inks

Due to the fluid nature of these silk inks, they must be coagulated in a reservoir to retain their filamentary shape during printing. We have shown that silk fibroin inks ( 29-30 wt%) flow readily through a 5 (tm nozzle and retain their fiber-like morphology upon deposition into a methanol-rich reservoir. Methanol is a poor solvent for silk fibroin and thus likely induces aggregation (dehydration) that drives a structural transition from random coil to P-sheet [28, 29]. However, despite their rapid solidification, they also adhere well to underlying filaments [7]. 

G") moduli as a function of shear rate for 29 wt% silk fibroin ink. (Reproduced with permission from [7]. Copyright 2008 Wiley-VCH Verlag GmbH. Co. KGaA.)... 

Silkworms, such as the Bombyx mori, produce silk fibroin that can be readily transformed into a filamentary form [27]. Regenerated silk fibroin, obtained from Bombyx mori cocoons, is soluble in aqueous solutions. However, this ink possesses a limited shelf life and a narrow compositional range over which its rheological properties are suitable for filamentary printing. To achieve the desired rheology... 

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