This invention presents the development of a solvent-free, viscoelastic liquid of regenerated silk fibroin (RSF) protein for writing and printing applications. By employing a bioconjugation methodology using polyethyleneimine (PEI) and an ethylene glycol-based polymer surfactant (PS), a dual coronal shell is formed around RSF, which inhibits intermolecular interactions and maintains the native silk I (random coil) conformation. The resulting RSF liquid exhibits a solid-to-liquid transition at approximately 45 °C, making it suitable for injection molding, compression molding, and casting into various shapes. Rheological studies reveal temperature-dependent viscoelastic and shear-thinning behavior, confirming the retention of the silk I structure. This RSF liquid remains stable in its silk I conformation for over eight months and can be utilized as an ink for writing, demonstrating tunable mechanical properties when crosslinked with glutaraldehyde vapor. This invention offers a novel approach to creating flexible, elastic, and mechanically tough materials with potential applications in biomaterials and printing technologies.
- Polymeric Interaction: The invention introduces a composite that retains the silk-I conformation in RSF fibroin by incorporating oppositely charged polyethyleneimine (PEI) and poly(ethylene glycol)-based surfactant (PS). This dual coronal shell prevents intermolecular interactions, maintaining the native random coil and helix-rich silk I structure.
- Long-term Stability: The specific composition of the viscoelastic RSF silk liquid, comprising 6 wt % RSF silk fibroin, 15 wt % PEI, and 77 wt % PS, is unique. This precise formulation ensures the formation of a stable, viscoelastic liquid that retains the silk I conformation and exhibits desirable phase transition properties.
- Solid-Liquid Transition: The RSF liquid transitions between solid and liquid states at 45-50 °C. It acts as a liquid above 45 °C for easy processing and molding and as a soft solid at room temperature, ideal for writing and shaping into various forms.
- Crosslinking and Structural Transition: Glutaraldehyde vapor at 50 °C induces a transition from silk I to silk II, allowing tunable mechanical properties for varying stiffness and strength based on application needs.
- Polymeric Interaction: The invention introduces a composite that retains the silk-I conformation in RSF fibroin by incorporating oppositely charged polyethyleneimine (PEI) and poly(ethylene glycol)-based surfactant (PS). This dual coronal shell prevents intermolecular interactions, maintaining the native random coil and helix-rich silk I structure.
- Long-term Stability: The specific composition of the viscoelastic RSF silk liquid, comprising 6 wt % RSF silk fibroin, 15 wt % PEI, and 77 wt % PS, is unique. This precise formulation ensures the formation of a stable, viscoelastic liquid that retains the silk I conformation and exhibits desirable phase transition properties.
- Solid-Liquid Transition: The RSF liquid transitions between solid and liquid states at 45-50 °C. It acts as a liquid above 45 °C for easy processing and molding and as a soft solid at room temperature, ideal for writing and shaping into various forms.
- Crosslinking and Structural Transition: Glutaraldehyde vapor at 50 °C induces a transition from silk I to silk II, allowing tunable mechanical properties for varying stiffness and strength based on application needs.
This research work has been published in a peer-reviewed journal (ACS Appl. Polym. Mater., 2022, 4, 4699-4708) as well as published as a US patent (Application No: US18/200,632)
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- Advancements in healthcare through improved biocompatible materials and drug delivery systems.
- Environmental sustainability through solvent-free processes and biodegradable materials.
- Empowerment of biomedical research in regenerative medicine and drug delivery.
- Reduction of environmental burden through biodegradability, especially in single-use applications
Biomedical, Healthcare, Textile and Apparel, 3D Printing and Additive Manufacturing, Aerospace and Automotive
The invention finds applications in biomedical engineering for tissue scaffolding and drug delivery, in textiles for high-performance fabrics and smart textiles, in 3D printing for bioprinting and customized biomedical devices, in packaging for biodegradable materials, in cosmetics for biocompatible skincare ingredients, in aerospace and automotive industries for lightweight materials, in electronics for flexible electronics and wearable devices, and in environmental applications for eco-friendly and biodegradable materials.
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