One-step synthesis of DNA functionalized cadmium-free quantum dots and its application in FRET-based protein sensing

- The stable and cadmium-free DNA functionalized ZnS:Mn2+ QDs were successfully synthesized through a facile one-step route.
- We constructed a novel FRET system based on one-step synthesized DNA-ZnS:Mn2+ QDs (donor) and WS2 nanosheets (acceptor).
- The FRET-based strategy was applied for the detection of streptavidin and folate receptor by combining TPSMLD and Exo III.

DNA functionalized quantum dots (QDs) are promising nanoprobes for the fluorescence resonance energy transfer (FRET)-based biosensing. Herein, cadmium-free DNA functionalized Mn-doped ZnS (DNA-ZnS:Mn2+) QDs were successfully synthesized by one-step route. As-synthesized QDs show excellent photo-stability with the help of PAA and DNA. Then, we constructed a novel FRET model based on the QDs and WS2 nanosheets as the energy donor-acceptor pairs, which was successfully applied for the protein detection through the terminal protection of small molecule-linked DNA assay. This work not only explores the potential bioapplication of the DNA-ZnS:Mn2+ QDs, but also provides a platform for the investigation of small molecule-protein interaction.

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