Stimuli-responsive azobenzene-quantum dots for multi-sensing of dithionite, hypochlorite, and azoreductase


A new fluorescence turn-on sensing platform has been developed applicable for sensitive profiling of multiple chemical and biological analytes, using azobenzene-quantum dot as a new stimuli-responsive optical nanoprobe. An azobenzene-carrying compound bis [4, 4′-(dithiophenyl azo)-1, 3-benzenediamine] (DTPABDA) is for the first time reported to be used for conjugation with CdSe/ZnS core/shell quantum dots (QDs) via the ligand exchange reaction. Due to the photo-induced electron-transfer (PET) effect, the electron-withdrawing azobenzene groups of DTPABDA can significantly cause the photoluminescence (PL) of QDs quenched. The QDs’ PL can be subsequently reignited by the removal of azo moiety cleavable through three types of specific reactions: the dithionite reduction, hypochlorite oxidation, and azoreductase enzymatic catalysis, respectively. By monitoring of reaction-induced recovery of FL signals at 560 nm with an excitation of 450 nm, such azobenzene-QDs conjugates served as a new nanoprobe enabling the fluorescence turn-on sensing of dithionite, hypochlorite, and azoreductase with high sensitivity, broad linear range, and good selectivity. The successful detection of target analytes in real samples reveals the potential of our method in practical applications, such as biosensing, environmental and industrial monitoring.

A new stimuli-responsive fluorescence probe is reported for the sensitive detection of sodium dithionite, hypochlorite, and azoreductase. The probe consists of QDs with an azobenzene-carrying compound as a ligand. The fluorescence of QDs could be quenched by the azo group and subsequently recovered via the removal of azo group by these three compounds, resulting in the “turn-on” sensing of these compounds with high sensitivity, broad linear range, and good selectivity. The successful detection of azoreductase in serum samples reveals the practical use of this method.

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This work was supported by the Guangdong Basic and Applied Basic Research Foundation (2020A1515010957), the Fundamental Research Funds for the Central Universities (No. 21618414), the Open Funds of the State Key Laboratory of Electroanalytical Chemistry (No. SKLEAC201903), and the Guangdong Innovative and Entrepreneurial Research Team Program (No. 2014ZT05S136).

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Correspondence to Nan Li.

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Zha, Y., Xin, R., Zhang, M. et al. Stimuli-responsive azobenzene-quantum dots for multi-sensing of dithionite, hypochlorite, and azoreductase. Microchim Acta 187, 481 (2020).

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  • Quantum dots
  • Azobenzene
  • Fluorescent nanoprobe
  • Biosensing
  • Chemical sensors