title: Programming function into mechanical forms by directed assembly of silk bulk materials.
abstract: We report simple, water-based fabrication methods based on protein self-assembly to generate 3D silk fibroin bulk materials that can be easily hybridized with water-soluble molecules to obtain multiple solid formats with predesigned functions. Controlling self-assembly leads to robust, machinable formats that exhibit thermoplastic behavior consenting material reshaping at the nanoscale, microscale, and macroscale. We illustrate the versatility of the approach by realizing demonstrator devices where large silk monoliths can be generated, polished, and reshaped into functional mechanical components that can be nanopatterned, embed optical function, heated on demand in response to infrared light, or can visualize mechanical failure through colorimetric chemistries embedded in the assembled (bulk) protein matrix. Finally, we show an enzyme-loaded solid mechanical part, illustrating the ability to incorporate biological function within the bulk material with possible utility for sustained release in robust, programmably shapeable mechanical formats.
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Benedetto
authors.identifier: 0000-0001-5311-6961
authors.initials: B
authors.lastname: Marelli
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Nereus
authors.initials: N
authors.lastname: Patel
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Thomas
authors.initials: T
authors.lastname: Duggan
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Perotto
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Elijah
authors.initials: E
authors.lastname: Shirman
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Li
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.|Department of Chemical Engineering, Tufts University, Medford, MA 02155.
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
authors.affiliation: Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155; fiorenzo.omenetto@tufts.edu.|Department of Electrical Engineering, Tufts University, Medford, MA 02155.|Department of Physics, Tufts University, Medford, MA 02155.
authors.forename: Fiorenzo G
authors.initials: FG
authors.lastname: Omenetto
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D012831:Bombyx; D020285:Cryoelectron Microscopy; D005349:Fibroins / Q000737:chemistry; D020100:Hydrogels; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology; D044367:Phase Transition; D047011:Silk / Q000737:chemistry*; D014867:Water
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D047011:Silk; D014867:Water; D005349:Fibroins
keywords: assembly; bioinspired; biomaterials; silk; sol–gel