Precise Spectral Overlap-Based Donor–Acceptor Pair for a Sensitive Traffic Light-Typed Bimodal Multiplexed Lateral Flow Immunoassay

Abstract

Bimodal-type multiplexed immunoassays with complementary mode-based correlation analysis are gaining increasing attention for enhancing the practicability of the lateral flow immunoassay (LFIA). Nonetheless, the restriction in visually indistinguishable multitargets induced by a single fluorescent color and difficulty in single acceptor ineffectual fluorescence quenching due to the various spectra of multiple different donors impede the further execution of colorimetric−fluorescence bimodal-type multiplexed LFIAs. Herein, the precise spectral overlap-based donor−acceptor pair construction strategy is proposed by regulating the size of the nanocore, coating it with an appropriate nanoshell, and selecting a suitable fluorescence donor with distinct colors. By in situ coating Prussian blue nanoparticles (PBNPs) on AuNPs with a tunable size and absorption spectrum, the resultant APNPs demonstrate efficient fluorescence quenching ability, higher colloidal stability, remarkable colorimetric intensity, and an enhanced antibody coupling efficiency, all of which facilitate highly sensitive bimodal-type LFIA analysis. Following integration with competitive-type immunoreaction, this precise spectral overlap-supported spatial separation traffic light-typed colorimetric−fluorescence dual-response assay (coined as the STCFD assay) with the limits of detection of 0.013 and 0.152 ng mL −1 for ractopamine and clenbuterol, respectively, was proposed. This work illustrates the superiority of the rational design of a precise spectral overlap-based donor−acceptor pair, hinting at the enormous potential of the STCFD assay in the point-of-care field.

“Three-in-One”: Ultrasensitive Lateral Flow Immunoassay Driven by Magnetic Enrichment and Photothermal Signal Amplification

“…With the LFIA, signal tracers are coupled with antibodies to form immunoprobes, which act as signal converters to reflect the analysis results and then act as a signal generator for transforming the analysis results . Considering that ZFOs were employed as the colorimetric and photothermal reporters, the colorimetric-based optical performance was first assessed by dripping different concentrations of ZFOs and AuNPs (traditional colorimetric signal labels employed for comparison) onto the NC membrane.…”

Fortified Dual-Spectral Overlap with Enhanced Colorimetric/Fluorescence Dual-Response Immunochromatography for On-Site Bimodal-Type Gentamicin Monitoring

“…The Arg/ATT-AuNCs were synthesized in two steps: First, 80 mM ATT was dissolved in 0.2 M NaOH and mixed with isopyknic 1% HAuCl 4 ·3H 2 O solution. Second, after reacting in the dark with 1 h, the Arg/ATT-AuNCs were synthesized by 40 mM Arg solution added to the above solution and heated to 37 °C with 24 h. Considering that the metal-based Arg/ATT-AuNCs were difficult to directly attach on the NC membrane, thus Arg/ATT-AuNCs-BSA was synthesized by the EDC/NHS strategy to output fluorescence signal through the immobilization effect of BSA . Briefly, 10 mg mL –1 EDC and NHS solutions were added to the above concentration for 30 min, and 100 mg mL –1 BSA solution was added to obtain Arg/ATT-AuNCs-BSA after another 3 h.…”