Fig. 1.

In vivo and in vitro biosynthesis of various single-element NMs. (A) Thirty-four single elements (shown in the black closed circle) tested to biosynthesize various NMs are shown in the latest version of the Periodic Table (November 28, 2016) from the International Union of Pure and Applied Chemistry (https://iupac.org/what-we-do/periodic-table-of-elements/). Elements such as diatomic nonmetals (blue border circle), noble gasses (red border circle), precious and expensive elements (gray border circle), major components of biomolecules and essential cations of the cell (light-green border circle) (37) and elements having insoluble precursors (orange border circle) and radioactive elements (yellow border circle) were excluded from the precursor candidates in this work. (B) The map of plasmid pYJ-MT-PCS used to construct recombinant E. coli DH5α strain employed in 34 single-element screenings for the biosynthesis of NMs. In vivo reactions were performed for 12 h unless indicated specifically. MT and PCS are coexpressed from each plasmid under the separate tac promoter. (C) TEM images of nine crystalline NMs synthesized in vivo with their corresponding elements labeled in green circle. (D) TEM images of 12 amorphous NMs synthesized in vivo with their corresponding elements labeled in yellow circle. (E) TEM images of crystalline Mn₃O₄ and In(OH)₃ NMs and amorphous Zr NM synthesized in vivo by a 6-h reaction with their corresponding elements labeled in black circle. (F) TEM images of crystalline Ag NM and amorphous Se NM synthesized in vivo using a control E. coli DH5α strain harboring an empty vector pTac15K with their corresponding elements labeled in dark-gray circle. (G) TEM images of seven crystalline NMs synthesized in vitro with their corresponding elements labeled in purple circle. (H) TEM images of four amorphous NMs synthesized in vitro with their corresponding elements labeled in pink circle. (I) TEM images of crystalline Mn₃O₄, Ag, and SnO₂ NMs synthesized in vitro using the cell extract of the control E. coli strain harboring an empty vector with their corresponding elements labeled in light-gray circle.