Engineering a living biomaterial via bacterial surface capture of environmental molecules

Abstract

Synthetic biology holds significant potential in biomaterials science as synthetically engineered cells can produce new biomaterials, or alternately, can function as living components of new biomaterials. Here, we describe the creation of a new biomaterial that incorporates living bacterial constituents that interact with their environment using engineered surface display. We first developed a gene construct that enabled simultaneous expression of cytosolic mCherry and a surface-displayed, catalytically active enzyme capable of covalently bonding with benzylguanine (BG) groups. We then created a functional living material within a microfluidic channel using these genetically engineered cells. The material forms when engineered cells covalently bond to ambient BG-modified molecules upon induction. Given the wide range of materials amenable to functionalization with BG-groups, our system provides a proof-of-concept for the sequestration and assembly of BG-functionalized molecules on a fluid-swept, living biomaterial surface.

Engineered Living Materials For Sustainability

“…9a). 140 It has been reported that each E. coli cell expresses up to 100000 copies of OmpA, making it theoretically possible to display chimeric fusion proteins at a high density on the microbial surface. 141 The surface display of SNAP-tagged proteins enables microorganisms to covalently bind benzylguanine (BG)modified molecules in the environment, providing proof of concept for sequestering and assembling BG-functionalized molecules on the surface of the material (Figure 9b).…”

“…coli, such as OmpA, intimin, and HlyAc (C-terminal fragment of hemolysin-protein A). Scott et al fused OmpA with a SNAP-tag, an O 6 -alkyl guanine DNA alkyltransferase from humans, to design living materials to capture environmental molecules (Figure a) . It has been reported that each E.…”

“…The functional SNAP-tag was fused to the Lpp-OmpA anchor protein for surface display. Reproduced with permission from ref . Copyright 2018 Oxford University Press.…”

“…(b) Decorating cell surfaces with the SNAP-tag enabled the formation of covalent bonds with environmental BG-modified molecules. Reproduced with permission from ref . Copyright 2018 Oxford University Press.…”

“…141 The surface display of SNAP-tagged proteins enables microorganisms to covalently bind benzylguanine (BG)modified molecules in the environment, providing proof of concept for sequestering and assembling BG-functionalized molecules on the surface of the material (Figure 9b). 140 In another example, displaying specific antibody−antigen pairs on microbial surfaces can generate programmed multicellular morphologies 138,142 and self-healing materials. 143 Chen et al developed a living conductive material consisting of two strains of E. coli with outer membrane-anchored bacterial adhesion proteins, one expressing a nanobody and the other an antigen.…”