Scalable Production of Genetically Engineered Nanofibrous Macroscopic Materials via Filtration

Abstract

As interest in using proteins to assemble functional, biocompatible and environmentally- friendly materials is growing, developing scalable protocols for producing recombinant proteins coupled to straightforward fabrication processes is becoming crucial. Here, we use E. coli bacteria to produce amyloid protein nanofibers that are key constituents of the biofilm extracellular matrix, and show that protein nanofiber aggregates can be purified using a fast and easily accessible vacuum filtration procedure. With their high resistance to heat, detergents, solvents and denaturing agents, engineered curli nanofibers remain functional throughout the rigorous processing, and can be used to assemble macroscopic materials. As a demonstration, we show that engineered curli nanofibers can be fabricated into self-standing films while maintaining the functionality of various fused domains that confer new specific binding activity to the material. We also demonstrate that purified curli fibers can be disassembled, reassembled into thin films, and recycled for further materials processing. We envision this scheme as an easily adoptable method for those interested in the scalable production of engineered protein- based materials.