Engineered from Waste: Ionic Liquid Processing of Keratin for 3D Printing Biomedical Scaffolds

Keratin holds significant potential for biomedical applications due to its superior cytocompatibility and ability to promote cellular migration and differentiation. However, despite these advantages, keratin processing is difficult due to its limited solubility in water and most common organic solvents. Herein, a sustainable and cost-effective approach was used for chicken feather dissolution (a keratin-rich waste) using acetate-based ionic liquids. This method simplifies the development of three-dimensional (3D) structures via directly embedded 3D printing keratin dissolved in ionic liquids (ILs). Using a carbonate-bicarbonate agarose microparticle support bath, we successfully promoted disulfide exchange and direct cross-linking of printed structures with diverse patterns and geometries, exhibiting excellent structural integrity. A comprehensive analysis of the rheological, mechanical, and biological properties was conducted, highlighting their potential biomedical applications. Interestingly, the scaffolds exhibited a dynamic shape-change over time, mediated by cellular traction forces, demonstrating their potential for 4D printing toward innovative bioapplications.