Silk Fibroin-Based Multiple-Shape-Memory Organohydrogels

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Organohydrogels (OHGs) possess unique hydrophilic and hydrophobic domains, enabling remarkable properties and versatility.
• Silk fibroin (SF) is a biocompatible protein with potential for advanced material fabrication.

Purpose of the Study:

• To develop a simple, cost-effective method for fabricating silk fibroin-based organohydrogels (SF-OHGs).
• To engineer SF-OHGs with multistage switching mechanics, tunable viscoelasticity, and multiple-shape-memory behaviors.

Main Methods:

• Fabrication of SF-OHGs via emulsion photopolymerization of n-octadecyl acrylate (C18A) and long-chain hydrocarbons (HCs) in an aqueous SF solution.
• Tuning transition temperatures by altering HC chain length and mass proportion.
• Characterization of shape-memory properties, including triple- and quintuple-shape memory effects.

Main Results:

• Successfully synthesized nonswelling SF-OHGs with multiple-shape-memory behavior.
• Achieved tunable transition temperatures ranging from 7 to 70 °C by modifying HC components.
• Demonstrated triple- and quintuple-shape memory effects in OHGs with combined poly(C18A) and HC microinclusions.

Conclusions:

• The developed method provides a facile route to engineer SF-OHGs with controllable shape-memory properties.
• Tunable transition temperatures and multistage shape-memory capabilities make these SF-OHGs promising for advanced applications.
• The combination of SF, C18A, and various HCs offers a versatile platform for designing functional organohydrogels.