Time-Resolved FRET-Based Immunosensor for the Ultrasensitive and Rapid Detection of Cd2+

The detection of heavy metals in food is beneficial topublic health.Herein, a new time-resolved fluorescent immunosensor based on theFo''rster resonance energy transfer (FRET) was proposed to rapidlydetect a cadmium ion (Cd2+). After coupling with an antigenand 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-antibodycombination to quench fluorescence through FRET. Under optimal conditions,the Eu-GNF immunosensing platform provided a quick response to Cd2+ within 30 min. The limit of detection was 0.29 ng/mL witha linear range of 1-500 ng/mL. This immunosensor was furthervalidated via graphite furnace atomic absorption spectrometry andexhibited satisfactory recovery for the detection of Cd2+ in four kinds of tea samples (98.82-108.01%). Thus, thisstrategy provides a good paradigm for the rapid and high-throughputdetection of heavy metals in field testing.

Automated summary

A new time-resolved fluorescent immunosensor based on FRET was developed for the rapid detection of cadmium ion. The immunosensor showed a quick response time of 30 minutes, a detection limit of 0.29 ng/mL, and a linear range of 1-500 ng/mL. The accuracy of the immunosensor for cadmium ion detection was further validated through testing tea samples, exhibiting satisfactory recovery rates. This method provides a good model for the rapid and high-throughput detection of heavy metals.