Fluorescent nanosensors for selective and sensitive determination of isoquercitrin based on boronate affinity-based imprinted quantum dots

A novel class of imprinted quantum dots as fluorescent nanosensors were prepared based on boronate affinity-based template-immobilization surface imprinting for detection of isoquercitrin (Isq). The obtained molecularly imprinted silica coating was used as the recognition element. The quantum dots were used as signal-transduction materials. Under optimum conditions, according to the fluorescence quenching of imprinted APBA-functionalized CdTe QDs by Isq, the imprinting factor (IF) for Isq was evaluated to be 1.69. This result suggests that boronic acid-functionalized quantum dots coated with molecularly imprinted silica were successfully prepared. The prepared isoquercitrin-imprinted APBA-functionalized CdTe QDs exhibited high sensitivity and selectivity toward isoquercitrin. The isoquercitrin-imprinted CdTe QDs exhibited linear fluorescence quenching toward isoquercitrin within the range of 0.20-30 mu M. And the detection limit was found to be 0.09 mu M. In addition, this study also provides an efficient fluorescence detection method of other cis-diol-containing flavonoids in samples. This method may find widespread use for monitoring of trace flavonoid drugs owing to its advantages of simple preparation, low cost, high sensitivity, good stability and reproducibility.