Materials fabrication from Bombyx mori silk fibroin

Abstract

Silk fibroin, derived from Bombyx mori cocoons, is a widely used and studied protein polymer for biomaterial applications. Silk fibroin has remarkable mechanical properties when formed into different materials, demonstrates biocompatibility, has controllable degradation rates from hours to years and can be chemically modified to alter surface properties or to immobilize growth factors. A variety of aqueous or organic solvent-processing methods can be used to generate silk biomaterials for a range of applications. In this protocol, we include methods to extract silk from B. mori cocoons to fabricate hydrogels, tubes, sponges, composites, fibers, microspheres and thin films. These materials can be used directly as biomaterials for implants, as scaffolding in tissue engineering and in vitro disease models, as well as for drug delivery.

Fig 1

Schematic of material forms fabricated from silk fibroin using both organic solvent and aqueous-based processing approaches. Overall, the silk fibroin extraction process takes 4 days and the time within the arrows indicates the time required to process the aqueous silk fibroin solution into the material of choice.

Fig 2

Schematic of the silk fibroin extraction procedure. Starting from the raw material (cocoons) to the final aqueous-based solution will take 4 days.

Fig 3

Schematic for making dipped silk tubes.

Fig 4

Schematic for making gel spun tubes.

Fig 5

Methods of preparing silk hydrogels.

Fig 6

Schematic for making patterned and non-patterned silk films.

Fig 7

Schematic of silk microsphere preparation using DOPC.

Fig 8

Schematic of silk microsphere preparation using PVA.

Fig 9

Method to prepare electrospun silk fibers.

Fig 10

Schematic to make aqueous-based silk sponges.

Fig 11

Method to prepare HFIP-based silk sponges.