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Fabrication of elastomeric silk fibers
Author(s) -
Bradner Sarah A.,
Partlow Benjamin P.,
Cebe Peggy,
Omenetto Fiorenzo G.,
Kaplan David L.
Publication year - 2017
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.23030
Subject(s) - silk , crystallinity , microfiber , fibroin , self healing hydrogels , elastomer , biomaterial , polymer , nanofiber , composite material , materials science , electrospinning , fiber , synthetic fiber , fabrication , chemical engineering , chemistry , nanotechnology , polymer chemistry , medicine , alternative medicine , engineering , pathology
Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross‐links, and generating double network hydrogels consisting of chemical and physical cross‐links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1–5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross‐links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross‐linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom‐up assembly of biological tissues and for broader biomaterial applications.