Time-Resolved FRET-Based Immunosensor for the Ultrasensitive and Rapid Detection of Cd<sup>2+</sup>
Zi Han, Yi Pan, Shuiliang Chen, Xinlin Wei
Abstract
The detection of heavy metals in food is beneficial to public health. Herein, a new time-resolved fluorescent immunosensor based on the Förster resonance energy transfer (FRET) was proposed to rapidly detect a cadmium ion (Cd 2+ ). After coupling with an antigen and a monoclonal antibody (mAb), respectively, the synthesized europium (III)-chelate-doped polystyrene time-resolved fluorescence microsphere-antigen (Eu-antigen) and gold nanoflowers-mAb (GNFs-mAb) interacted by antigen–antibody combination to quench fluorescence through FRET. Under optimal conditions, the Eu-GNF immunosensing platform provided a quick response to Cd 2+ within 30 min. The limit of detection was 0.29 ng/mL with a linear range of 1–500 ng/mL. This immunosensor was further validated via graphite furnace atomic absorption spectrometry and exhibited satisfactory recovery for the detection of Cd 2+ in four kinds of tea samples (98.82–108.01%). Thus, this strategy provides a good paradigm for the rapid and high-throughput detection of heavy metals in field testing.