Nano-biohybrid Organisms: In-vivo Targeting of Enzymes with Quantum Dots for Light-Driven Renewable Biochemical Synthesis

Living cells do not interface naturally with nanoscale materials, although such artificial organisms can have unprecedented multifunctional properties, like wireless activation of enzyme function using electromagnetic stimuli. Realizing such interfacing in a nanobiohybrid organism (or nanorg) requires (1) chemical coupling via affinity binding and self-assembly, (2) the energetic coupling between optoelectronic states of artificial materials with the cellular process, and (3) the design of appropriate interfaces ensuring biocompatibility. We have shown that many different core−shell quantum dots (QDs) couple with targeted enzyme sites in bacteria. When illuminated by light, these QDs drive the renewable production of different biofuels and chemicals using carbon dioxide, water, and nitrogen (from air) as substrates. Together, these nanorgs catalyze light-induced air−water−CO2 reduction to synthesize biofuels like isopropanol, 2,3-butanediol, C11−C15 methyl ketone, hydrogen gas; and valued chemicals such as formic acid, ammonia, ethylene, and degradable bioplastics polyhydroxybutyrate. Therefore, these resting cells function as nano-microbial factories that synthesize valuable chemicals from abundant small molecuels powered by the sun.