Quantum dots–bienzyme hybrid system for the sensitive determination of glucose

In this paper, we attempt to develop a sensitive detection method for glucose with the combination of the unique optical property of quantum dots and the specificity of enzymatic reactions. With glucose and hydroquinone as substrates, benzoquinone that intensively quenches the photoluminescence of quantum dots can be produced via the catalysis of bienzyme (glucose oxidase and horseradish peroxidase) system. A relatively low detection limit of 1.0 × 10−8 mol/L can be achieved. Two linear ranges from 1.0 × 10−6 to 1.5 × 10−4 M and from 1.5 × 10−4 to 1.0 × 10−3 M were obtained. For the detection of 1.0 × 10−4 M glucose, six replicative measurements showed the reproducibility (R.S.D.) of 4.43%. The quantum dots–enzymes system possesses advantages of simple procedure without modification of quantum dots or immobilization of enzymes, low cost, high sensitivity and short detection times within several minutes.