Composites from Self-Assembled Protein Nanofibrils and Liquid Metal Gallium

Gallium (Ga), a low-melting-point liquid metal with soft, metallic, and biocompatible properties, offers many possibilities. However, the potential of composites that integrate Ga with biomacromolecules, combining their biocompatibility, elasticity, and conductivity, has not been thoroughly explored, which is a gap for advancing these composites in various applications. In parallel and independently, protein self-assembled l.,;3bhnanofibrils have attracted great interest as building blocks for functional biomaterials. Here, composites of Ga droplets and nanofibrils are presented, self-assembled from plant proteins of soy protein isolate (SPI). It is evidenced that in these composites self-assembled SPI nanofibrils can effectively reduce the oxidation of Ga droplets. It is observed that the composites of beta-sheet nanofibrils and Ga droplets offer mechanical properties similar to only fibrils-based films. Films of 32 wt% Ga in SPI showed enhanced electrical conductivity and well-structured nanofibrils with multifunctional potential in gas-sensing and electronically controlled antibacterial applications. It is illustrated that the 32 wt% Ga in SPI composite offered the best sensing performance for a diatomic molecule, CO, and electro-stimulation of this composite effectively reduced bacterial growth. The Ga in SPI composite, combining the advantages of protein nanofibrils and Ga droplets, offers great potential in future biomedical applications. Composites of gallium (Ga) droplets and nanofibrils from plant-based soy protein isolate (SPI) are presented. Nanofibrils reduce the oxidation of the surface of Ga droplets, sintering them. The SPI-Ga composite films are electrically conductive organic-inorganic hybrids. These composites offer multifunctional capabilities for gas-sensing and electronically controlled antibacterial applications. image