A Simple and Sensitive Fluorimetric Aptasensor for the Ultrasensitive Detection of Arsenic(III) Based on Cysteamine Stabilized CdTe/ZnS Quantum Dots Aggregation, Ali A. Ensafi, N. Kazemifard, B. Rezaei, Biosensors & Bioelectronics, 2016, 7, 499-505.
A new approach for developing a ﬂuorimetric aptasensor has been described and applied for determi-
nation of a highly toxic cation, As(III). In this method an aptamer was used to aggregate cationic cy-
steamine-stabilized CdTe/ZnS core/shell quantum dots, as a result ﬂuorescence quenching was accrued.
In the presence of As(III), the aptamer and As(III) make a complex, which prevents aggregation of the
quantum dots. Thus, the ﬂuorescence intensity of the quantum dots was enhanced upon the de-ag-
gregation, which depends on the concentration of As(III). The ﬂuorimetric assay has a very low detection
limit of 1.3 pmol L1 As(III) with a dynamic range of 1.0 10 –11 to 1.0 10 –6 mol L 1 . The interference
effect of a wide variety of cations and anions was investigated, and the obtained results conﬁrm high
selectivity of the aptasensor for As(III) detection. The present assay was successfully applied for the
determination of As(III) in several water samples.