Programmable biofilm-based materials from engineered curli nanofibres

Abstract

The significant role of biofilms in pathogenicity has spurred research into preventing their formation and promoting their disruption, resulting in overlooked opportunities to develop biofilms as a synthetic biological platform for self-assembling functional materials. Here we present Biofilm-Integrated Nanofiber Display (BIND) as a strategy for the molecular programming of the bacterial extracellular matrix material by genetically appending peptide domains to the amyloid protein CsgA, the dominant proteinaceous component in Escherichia coli biofilms. These engineered CsgA fusion proteins are successfully secreted and extracellularly self-assemble into amyloid nanofibre networks that retain the functions of the displayed peptide domains. We show the use of BIND to confer diverse artificial functions to the biofilm matrix, such as nanoparticle biotemplating, substrate adhesion, covalent immobilization of proteins or a combination thereof. BIND is a versatile nanobiotechnological platform for developing robust materials with programmable functions, demonstrating the potential of utilizing biofilms as large-scale designable biomaterials.

Amyloid Structures as Biofilm Matrix Scaffolds

“…The other work describes a biofilm-integrated nanofiber display (BIND) system that consists of genetically programming the E. coli biofilm extracellular matrix by fusing functional peptide domains to the CsgA protein. This technique is compatible with a wide range of peptide domains of various lengths and secondary structures, since they maintain their function after secretion and assembly, conferring artificial functions to the biofilm as a whole (98) (Fig. 3A).…”

Portable, On-Demand Biomolecular Manufacturing

“…Nanobody and DARPin sequences were cloned into pET15b. The His-YFPSpyCatcher and -Amylase-SpyCatcher plasmids have been previously cloned and described (Botyanszki et al, 2015;Nguyen et al, 2014) …”

Synthetic Morphogenesis

“…Layering synthetic control mechanisms on top of preexisting morphogenic modules in a "simple" chassis such as E. coli partially addresses issues of pleiotropy that plague current efforts, because engineers can change the behavior of the morphogenic modules (such as functionalizing the CsgA protein; Nguyen et al 2014), confident that they understand those changes' effects in the context of a broader system. However, it may be that the palette of morphogenic behaviors available in a bacterial system is not broad enough.…”

“…Recent work has shown functionalization of CsgA, the protein that forms E. coli biofilms, with peptide tags conferring activities such as substrate-specific adhesion and electrical conductivity (Fig. 3) (Chen et al 2014;Nguyen et al 2014).…”