Building quantum dot-bacteria nano-biohybrids for light-driven renewable biochemical synthesis

Live cells do not interface naturally with nanostructures, although such artificial organisms can have unprecedented multifunctional properties, like wireless activation of enzyme function using electromagnetic stimuli. Realizing such interfacing requires (1) chemical coupling via affinity binding and self-assembly, (2) energetic coupling between material optoelectronic states and the cellular process, and (3) design of appropriate interfaces ensuring biocompatibility. Here we show different core-shell quantum dots (QDs), with excitations ranging from UV to NIR, couple with targeted enzyme sites in bacteria. When illuminated by light, these QDs drive the renewable production of different biofuels and chemicals using CO₂, water, and N₂ as substrates. These QDs use their zinc-rich shell facets for affinity binding to the enzymes. Cysteine zwitterion ligands enable uptake through the cell, facilitating cell survival. Together, these nanorgs catalyze light-induced air-water-CO₂ reduction with a high turnover number of ~10⁶-10⁸ (mols/mol of cells) to biofuels like C₂H₄, 2-propanol, 2,3-butanediol, methyl ketones, and H₂; and chemicals such as formate, NH₃, and bioplastics. Therefore, these resting cells function as nano-microbial factories powered by light.

Ref: JACS, 2019, 141, 10272