nn9b01581_si_001.pdf (1.22 MB)
Substrate Metabolism-Driven Assembly of High-Quality CdSxSe1–x Quantum Dots in Escherichia coli: Molecular Mechanisms and Bioimaging Application
journal contribution
posted on 2019-04-10, 00:00 authored by Li-Jiao Tian, Yuan Min, Wen-Wei Li, Jie-Jie Chen, Nan-Qing Zhou, Ting-Ting Zhu, Dao-Bo Li, Jing-Yuan Ma, Peng-Fei An, Li-Rong Zheng, Hai Huang, Yang-Zhong Liu, Han-Qing YuBiosynthesis
offers opportunities for cost-effective and sustainable
production of semiconductor quantum dots (QDs), but is currently restricted
by poor controllability on the synthesis process, resulting from limited
knowledge on the assembly mechanisms and the lack of effective control
strategies. In this work, we provide molecular-level insights into
the formation mechanism of biogenic QDs (Bio-QDs) and its connection
with the cellular substrate metabolism in Escherichia coli. Strengthening the substrate metabolism for producing more reducing
power was found to stimulate the production of several reduced thiol-containing
proteins (including glutaredoxin and thioredoxin) that play key roles
in Bio-QDs assembly. This effectively diverted the transformation
route of the selenium (Se) and cadmium (Cd) metabolic from Cd3(PO4)2 formation to CdSxSe1–x QDs assembly,
yielding fine-sized (2.0 ± 0.4 nm), high-quality Bio-QDs with
quantum yield (5.2%) and fluorescence lifetime (99.19 ns) far exceeding
the existing counterparts. The underlying mechanisms of Bio-QDs crystallization
and development were elucidated by density functional theory calculations
and molecular dynamics simulation. The resulting Bio-QDs were successfully
used for bioimaging of cancer cells and tumor tissue of mice without
extra modification. Our work provides fundamental knowledge on the
Bio-QDs assembly mechanisms and proposes an effective, facile regulation
strategy, which may inspire advances in controlled synthesis and practical
applications of Bio-QDs as well as other bionanomaterials.