News Release

Creating super biosystems via space−time-coupled synthesis of nanocrystals in live cells

Peer-Reviewed Publication

Science China Press

Metabolic pathways in artificially regulated live-cell synthesis of fluorescent quantum dots in Saccharomyces cerevisiae and Escherichia coli.

image: In the case of live-cell synthesis of CdSe QDs, it is essential to produce both reactive Se- and Cd-containing precursors at the proper intracellular location and timepoint by modulating intracellular reductive metabolism of sodium selenite and the detoxification of cadmium ion. view more 

Credit: ©Science China Press

Cell has been exploited as a powerful tool to accomplish unexpected tasks through artificial regulation in the last decade. Given the numerous reactive intermediates generated in the sophisticated metabolic processes and the subtle redox balance supporting the cellular homeostasis, cell could function as a promising chemical factory. However, it’s still a challenge to direct these reactions and pathways to synthesize desired products since they are naturally existing in different spatiotemporal dimensions within the cell. Prof. Dai-Wen Pang group proposed a concept of “space-time coupled live-cell synthesis of nanocrystals”, namely synthesizing nanocrystals by purposefully and precisely coupling a series of intracellular redox reactions and metabolic pathways, in an appropriate spatial and temporal sequence in live cells.

Taking yeast cells as an example, fluorescent semiconductor CdSe quantum dots (QDs) with tunable emission wavelengths could be synthesized by coupling the intracellular reductive metabolism of sodium selenite (Na2SeO3) with the triggered detoxification of cadmium ion (Cd2+). By properly manipulating glutathione metabolic pathways, the yield of QDs could be raised greatly, indicating the critical role of glutathione during the generation of CdSe nanocrystals. This attractive strategy for the live-cell synthesis of nanocrystals has been subsequently expanded to bacterial cells and mammalian cells. Remarkably, cell-derived microvesicles can also be efficiently labeled in situ with intracellular-synthesized QDs. Due to the superior fluorescent properties, intrinsic high extinction coefficient, and biocompatibility, the intracellular-synthesized QDs and the QD-containing cells have been successfully transformed into nanobioprobes for biodetection, with an electron and energy relay in an artificial photosynthesis system being also created.

Inspired by the abovementioned mechanisms, cell-free quasi-biosynthesis systems that mimic the intracellular reactions have been developed to fabricate a variety of nanocrystals under mild conditions, such as noble-metal nanoparticles, alloy nanoparticles, fluorescent and functionalized QDs, and other inorganic nanocrystals. This universal quasi-biosynthesis is more flexible and diversified, which has further strengthened the methodology for biosynthesis.

Live cell, as a reservoir of biochemical reactions, can serve as an amazing integrated chemical plant where precursor formation, nanocrystal nucleation and growth, and functional assembly can be carried out accurately by artificial programming. However, the present artificial-regulated synthesis merely employs the tip of an iceberg of metabolic pathways. “We hope to intrigue more researchers to explore new strategies and mechanisms to produce diverse multifunctional crystals and even intricate heteronanostructures. The concept we proposed will enable researchers to better exploit the unanticipated potentialities of live cells, open a new window for the field of synthetic biology, and shed light on the interdisciplinary studies of biology, chemistry and medicine.” Prof. Pang says.

See the article:

Artificially regulated synthesis of nanocrystals in live cells

https://doi.org/10.1093/nsr/nwab162


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