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Chemical Redox Modulation of the Surface Chemistry of CdTe Quantum Dots for Probing Ascorbic Acid in Biological Fluids
Author(s) -
Chen YingJun,
Yan XiuPing
Publication year - 2009
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200900291
Subject(s) - ascorbic acid , förster resonance energy transfer , fluorescence , quantum dot , chemistry , cadmium telluride photovoltaics , photochemistry , redox , analyte , nanoparticle , biosensor , detection limit , nanotechnology , materials science , inorganic chemistry , biochemistry , physics , food science , chromatography , quantum mechanics
Most of the fluorescence resonance energy transfer (FRET)‐based sensors employing quantum dots (QDs) usually use organic fluorophores and gold nanoparticles as the quenchers. However, complex processes for the modification/immobilization of the QDs are always necessary, as the generation of FRET requires strict distance between the donor and acceptor. Herein, a simple chemical redox strategy for modulating the surface chemistry of the QDs to develop a QD‐based turn‐on fluorescent probe is reported. The principle of the strategy is demonstrated by employing CdTe QDs with KMnO 4 as the quencher and ascorbic acid as the target analyte. The fluorescence of CdTe QDs is quenched with a blue‐shift upon addition of KMnO 4 due to the oxidation of the Te atoms on the surface of the QDs. The quenched fluorescence of the QDs is then recovered upon addition of ascorbic acid due to the reduction of CdTeO 3 /TeO 2 on the surface of the QDs to CdTe. The recovered fluorescence of the QDs increases linearly with the concentration of ascorbic acid from 0.3 to 10 µ M . Thus, a novel QD‐based turn‐on fluorescent probe with a detection limit as low as 74 n M is developed for the sensitive and selective detection of ascorbic acid in biological fluids. The present approach avoids the complex modification/immobilization of the QDs involved in FRET‐based sensors, and opens a simple pathway to developing cost‐effective, sensitive, and selective QD‐based fluorescence turn‐on sensors/probes for biologically significant antioxidants.