Immobilization of functional nano-objects in living engineered bacterial biofilms for catalytic applications

Abstract

Nanoscale objects feature very large surface-area-to-volume ratios and are now understood as powerful tools for catalysis, but their nature as nanomaterials brings challenges including toxicity and nanomaterial pollution. Immobilization is considered a feasible strategy for addressing these limitations. Here, as a proof-of-concept for the immobilization of nanoscale catalysts in the extracellular matrix of bacterial biofilms, we genetically engineered amyloid monomers of the Escherichia coli curli nanofiber system that are secreted and can self-assemble and anchor nano-objects in a spatially precise manner. We demonstrated three scalable, tunable and reusable catalysis systems: biofilm-anchored gold nanoparticles to reduce nitro aromatic compounds such as the pollutant p-nitrophenol, biofilm-anchored hybrid Cd0.9Zn0.1S quantum dots and gold nanoparticles to degrade organic dyes and biofilm-anchored CdSeS@ZnS quantum dots in a semi-artificial photosynthesis system for hydrogen production. Our work demonstrates how the ability of biofilms to grow in scalable and complex spatial arrangements can be exploited for catalytic applications and clearly illustrates the design utility of segregating high-energy nano-objects from injury-prone cellular components by engineering anchoring points in an extracellular matrix.

Diatom-inspired multiscale mineralization of patterned protein–polysaccharide complex structures

“…With their rapid swelling feature and reversible swelling behavior, we hypothesize that the fabricated porous cubes would first serve as sponge-like materials to homogeneously absorb a mineralization precursor solution for TiO 2 mineralization, and then harbor a mixed reaction solution containing bacterial cells for artificial photosynthesis. Ideally, in the final constructed artificial photosynthesis system, mineralized TiO 2 nanoparticles would act as the light-antennae component converting photons into electrons, and an engineered E. coli strain harboring a hydrogenase gene cluster, upon receiving electrons transported by methyl viologen (MV), could catalyze continuous hydrogen evolution when the system was illuminated [ 50 ].…”

Encapsulation of bacterial cells in cytoprotective ZIF-90 crystals as living composites

“…[ 57 , 58 ]. Through synthetic biology, living systems (bacteria, fungi, mammalian cells, and so on) can also be engineered with a variety of user-defined capabilities [ 59 ]. The integration of MOF and living systems can effectively combine the advantages of both, and the resulting materials may show enhanced application potentials [ 24 ].…”

Strategic Advances in Spatiotemporal Control of Bioinspired Phenolic Chemistries in Materials Science

“…Last but not least, outstanding opportunities can lie ahead as a surprise in the integration of phenolic chemistries and living systems and biotechnology. [283][284][285] For example, phenolic polymerization/assembly can be adapted to engineer the interface or intracellular structures of living cells or protocells, [176,279,286,287] which can find emergent applications in cytoprotection, bioimaging, single cell manipulation, and origin-of-life modeling. Furthermore, we are keen to see the incorporation of phenolic chemistries into DNA origami and CRISPR-Cas technologies, which would give birth to programmable phenolic materials.…”