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

Abstract

The detection of heavy metals in food is beneficial to public health. Herein, a new time-resolved fluorescent immunosensor based on the Forster 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.

High-Density Au Anchored to Ti3C2-Based Colorimetric-Fluorescence Dual-Mode Lateral Flow Immunoassay for All-Domain-Enhanced Performance and Signal Intercalibration

“…The quenching ability of the fluorescence quencher is one of the chief parameters determining the sensitivity of fluorescence quenching LFIA . An equal volume of Ti 3 C 2 @Au or AuNP was mixed with 0.04 mg/mL TRFM for quenching and the fluorescence quenching efficiency was determined by the formula: E = F − F 0 F where E is the fluorescence quenching efficiency and F and F 0 are the fluorescence intensities of donors in the absence and presence of acceptors, respectively. Figure L demonstrate that the quenching efficiency of Ti 3 C 2 @Au (86.1% ± 0.1%) is higher than that of AuNP (77.9% ± 0.2%).…”

“…The quenching ability of the fluorescence quencher is one of the chief parameters determining the sensitivity of fluorescence quenching LFIA. 25 An equal volume of Ti 3 C 2 @Au or AuNP was mixed with 0.04 mg/mL TRFM for quenching and the fluorescence quenching efficiency was determined by the formula 26 :…”