Sustainable Processing and Synthesis of Nontoxic and Antibacterial Magnetic Nanocomposite from Spider Silk in Neoteric Solvents

Different neoteric solvents (both ionic liquids and deep eutectic solvents) were used for the dispersion and preparation of bionanocomposite of spider silk fibers (Crossopriza lyoni). Among these solvents, hydrated tetrabutylammonium hydroxide was found to disperse 7.5 mg mL^–1 of spider silk with nanoscale structural distribution at room temperature. Analyses of the regenerated spider silk from the solution indicated preservation of the chemical structures of the protein blocks in the fibers during the dispersion process. The quaternary ammonium based IL was further used as dispersion media for the fabrication of Fe₃O₄ functionalized bionanocomposite. Attachment of Fe₃O₄ nanoparticles on the spider silk surfaces and preservation of the chemical structures of the protein blocks of the spider silk in the composite was also established. The materials generated do not appear to inhibit the growth of mammalian cells in vitro and showed antibacterial properties and thus demonstrate their potential for therapeutic applications.