UC Berkeley

The interplay of chemistry and biology holds many opportunities to address the woes of the modern world. As synthetic chemistry and cell biology have married together to make great strides in health and medicine, an amalgamation of inorganic materials chemistry and microbiology holds similar promise to revolutionize our approach to transducing solar energy into chemical bonds. By combining the superior light harvesting of inorganic semiconductors with enzymatic biocatalysts, high efficiency solar-to-chemical production of complex molecules and materials may outcompete natural photosynthesis. In this work, I describe a series of investigations into the physical and chemical interactions of inorganic-biological hybrid organisms. In the Sporomusa ovata-silicon nanowire system, changes in salt concentrations predictably controlled cell-nanowire alignment, producing a predictive model of inorganic-biological colloidal interaction. The hybrid organism Moorella thermoacetica-cadmium sulfide self-photosensitized the synthesis of acetic acid from CO2 via bioprecipitated CdS nanoparticles. A titanium dioxide-manganese(II) phthalocyanine photocatalyst system extended oxygenic photosynthesis in M. thermoacetica-CdS through a photoregenerative cysteine-cystine redox couple. Finally, transient absorption spectroscopy, time-resolved infrared spectroscopy and biochemical assays suggested a two-pathway mechanism of charge and energy transport between M. thermoacetica and CdS. These initial works at the nexus of materials chemistry and biology lay the foundation for deeper understanding of this complex interface as well as for the development of advanced solar-to-chemical production systems.