Construction of CdTe@γ-CD@RBD nanoprobe for Fe3+-sensing based on FRET mechanism in human serum.

A Fe3+ optical sensor (CdTe@γ-CD@RBD) has been developed by using gamma-cyclodextrin (γ-CD) as a bridge to link CdTe quantum dots (QDs) and a Rhodamine B derivative (RBD). The RBD molecule can enter the cavity of the γ-CD anchored onto the surfaces of the QDs. In the presence of Fe3+, the fluorescence resonance energy transfer (FRET) process from QDs to RBD will be initiated, rendering the nanoprobe to display a response to Fe3+. The degree of fluorescence quenching presented a satisfactory linearity between 10 and 60 μΜ with the incremental concentrations of Fe3+, and the calculated limit of detection was 2.51 μΜ. Through sample pretreatment procedures, the probe has been used in the determination of Fe3+ in human serum. The average recoveries in the spiking levels are ranged from 98.60 % to 107.20 % with a relative standard deviation of around 1.43 %-2.96 %. This finding leads to a method for fluorescent detection of Fe3+ with high sensitivity and exceptional selectivity. We believe that this study can give a new insight into the rational design and application of FRET-based nanoprobes.