Solar-energy-facilitated CdSxSe1-x quantum dot bio-assembly in Escherichia coli and Tetrahymena pyriformis

Bio-assembled QDs (Bio-QDs) with unique biocompatibility and fluorescence features have diverse applications, including bio-imaging, biomedical detection, biological hydrogen production and solar-to-chemical conversion. However, their relatively low production rate and poor fluorescence properties are two major barriers. In this work, we demonstrate a novel and sustainable regulation method to improve the synthesis of Bio-QDs in prokaryotes and eukaryotes. We develop solar-energy-facilitated CdSxSe1-x Bio-QDs fabrication in Escherichia coli. The resulting Bio-QDs were assembled within 1 hour and have a long fluorescence lifetime (24.8 ns). Spectroscopic analyses revealed that the solar-energy-facilitated Bio-QD synthesis was due to the photocatalytic roles of the self-assembled Bio-QDs. Similar photo-assisted Bio-QD synthesis was also observed in eukaryotic model Tetrahymena pyriformis. This work provides a promising approach to use solar energy to produce Bio-QDs with a longer emission lifetime, which would favour fluorescence lifetime imaging microscopy applications